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diff --git a/75947-0.txt b/75947-0.txt new file mode 100644 index 0000000..c30a6cc --- /dev/null +++ b/75947-0.txt @@ -0,0 +1,34576 @@ + +*** START OF THE PROJECT GUTENBERG EBOOK 75947 *** + + + + + +AN INTRODUCTION TO THE STUDY OF MAMMALS + + + + + AN INTRODUCTION + TO THE STUDY OF + MAMMALS + LIVING AND EXTINCT + + BY + + WILLIAM HENRY FLOWER + C.B., F.R.S., D.C.L., LL.D., P.Z.S., F.L.S., F.G.S., &c. + DIRECTOR OF THE NATURAL HISTORY DEPARTMENTS, BRITISH MUSEUM + + AND + + RICHARD LYDEKKER + B.A., F.G.S., F.Z.S., &c. + + [Illustration: THE WOOLLY OPOSSUM] + + LONDON: ADAM AND CHARLES BLACK + MDCCCXCI + + + + +PREFACE + + +One of the greatest difficulties experienced by all who undertake a +work of this nature, not professing to be an exhaustive treatise on +the subject with which it deals, is to determine the amount of detail +desirable to be introduced to meet the requirements of the ordinary +student, without rendering it too bulky or costly for general use. The +experience of those who endeavour to profit by the book can alone decide +how far the authors have succeeded in this respect. It will be observed +that in many instances certain better-known or more interesting members +of the class have been described at considerable length, while it has +been necessary to treat others with much greater brevity. + +With regard to the references to the literature of the various groups +treated of, it has been the endeavour of the authors to make a selection +of such memoirs and works as are likely to prove most valuable to the +student for the amount of original information which they contain, and +more especially of those giving full bibliographical data up to the +time of their publication, the repetition of which has been considered +unnecessary. + +In a few instances new generic terms have been introduced to replace +some which were already occupied; these have been proposed by Mr. +Lydekker, and should be quoted as his. + +The work is based largely upon the article “Mammalia,” together with +forty shorter articles, written by the senior of the two authors for +the ninth edition of the Encyclopædia Britannica. The account of the +orders Rodentia, Insectivora, and Chiroptera contributed to the article +“Mammalia” by Dr. G. E. Dobson, F.R.S., as well as the articles “Mole,” +“Shrew,” and “Vampyre,” by the same writer, the articles “Marmot,” +“Mouse,” “Opossum,” “Phalanger,” “Rat,” “Squirrel,” “Stoat,” “Vole,” and +others, by Mr. Oldfield Thomas, and likewise the article “Ape,” by Dr. +St. G. Mivart, F.R.S., have also been made use of to a greater or less +extent. The best thanks of the authors are due to these three gentlemen +for freely permitting the incorporation of their own work in the present +volume. + +Mr. Lydekker undertook the task of arranging the various articles in +their proper sequence, selecting from these such portions as seemed +suitable, filling up the gaps, and adding new matter where necessary; a +large amount of this new matter treating of the extinct forms, and also +of the group Artiodactyla. + +The subsequent revision, both before being sent to the printers, and also +when passing through the press, has been made by both authors, who are +thus jointly responsible for the whole work. + +The illustrations are to a great extent those prepared for the various +articles in the Encyclopædia, but many have been added—some drawn +expressly for the work, and some borrowed from other publications. For +most of the latter the authors take this opportunity of expressing their +thanks to the Publication Committee of the Zoological Society of London, +as well as to the individual writers in whose works they first appeared. + +The authors have further much pleasure in acknowledging the ready and +obliging way in which Mr. Oldfield Thomas has, throughout the progress of +the work, placed his extensive knowledge of the group of animals of which +it treats at their disposal. + +LONDON, _March_ 1891. + + + + +CORRIGENDA. + + +Page 280, _for_ Chæropsis _read_ Chœropsis. + +Page 292, _for_ Chæropotamidæ and Chæropotamus _read_ Chœropotamidæ and +Chœropotamus. + +Page 590, _for_ Pæcilogale _read_ Pœcilogale. + +=Transcriber’s Note:= The corrections have been applied. + + + + +CONTENTS + + + PAGE + + CHAPTER I + + INTRODUCTORY REMARKS 1 + + Use of term mammals, 1; Characters of mammals, 2; + Development of young, 3; Size of mammals, 4; Uses and + products of mammals, 4. + + CHAPTER II + + GENERAL ANATOMICAL CHARACTERS 7 + + I. Tegumentary Structures 7 + + Hair, 7; Colour, 8; Scales, etc., 11; Nails, claws, and + hoofs, 12; Odour-secreting glands, 12. + + II. Dental System 13 + + Teeth, 13; Structure of teeth, 13; Development of teeth, 15; + Forms of teeth, 17; Succession of teeth, 19; Arrangement, + homologies, and notation of teeth, 21; Dental formulæ, + 25; Modifications of teeth in relation to function, 28; + Taxonomy, 30; Trituberculism, 30. + + III. The Skeleton 33 + + Definition, 33; Axial skeleton, 34; Skull, 34; Vertebral + column, 39; Cervical vertebræ, 41; Dorsal vertebræ, 42; + Lumbar vertebræ, 42; Sacral vertebræ, 43; Caudal vertebræ, + 43; Sternum, 44; Ribs, 44; Appendicular skeleton, 46; + Anterior limb, 46; Shoulder-girdle, 46; Brachium and + Antebrachium, 47; Manus, 48; Carpus, 48; Metacarpus and + Phalanges, 49; Posterior limb, 50; Pelvic girdle, 50; Thigh + and Leg, 51; Pes, 52. + + IV. The Digestive System 53 + + General considerations, 53; Mouth, 54; Salivary glands, 55; + Stomach, 57; Intestinal canal, 59; Liver, 60. + + V. Circulatory, Absorbent, Respiratory, and Urinary Systems 63 + + Blood, 63; Heart, 63; Lymphatic vessels, 65; Ductless + glands, 65; Nostrils, 66; Trachea, 67; Larynx, 67; + Diaphragm, 67; Lungs, 68; Air-sacs, 68; Urinary Organs, 69; + Bladder, 69. + + VI. Nervous System and Organs of Sense 69 + + Brain, 69; Nerves, 71; Sense of touch, 72; Taste and smell, + 72; Sight, 72; Hearing, 73. + + VII. Reproductive Organs 74 + + Testes, 74; Penis, 74; Ovaries and oviduct, 75; Mammary + glands, 75; Secondary sexual characters, 76; Placenta, 76. + + CHAPTER III + + ORIGIN AND CLASSIFICATION OF THE MAMMALIA 82 + + Origin, 82; Classification, 84; Table of orders and + families, 88. + + CHAPTER IV + + GEOGRAPHICAL AND GEOLOGICAL DISTRIBUTION 93 + + I. Geographical Distribution 93 + + Zoological regions, 96; Palæarctic region, 97; Ethiopian + region, 98; Oriental region, 100; Celebes, 102; Nearctic + region, 102; Neotropical region, 103; Aquatic mammals, 104. + + II. Geological Distribution 107 + + Sequence of strata, 107; Mesozoic mammals, 109; + Multituberculata, 109; Polyprotodont types, 113; Tertiary + mammals, 115. + + CHAPTER V + + THE SUBCLASS PROTOTHERIA OR ORNITHODELPHIA 117 + + General characters, 117. _Family_ ORNITHORHYNCHIDÆ, 119; + _Ornithorhynchus_, 119. _Family_ ECHIDNIDÆ, 124; _Echidna_, + 125; _Proechidna_, 126; Fossil species, 127. + + CHAPTER VI + + THE SUBCLASS METATHERIA OR DIDELPHIA 128 + + General characters, 128; Distribution, 131; Classification, + 131. + + _Suborder_ POLYPROTODONTIA 133 + + _Family_ DIDELPHYIDÆ, 133; _Chironectes_, 134; _Didelphys_, + 135. _Family_ DASYURIDÆ, 136; _Subfamily_ Dasyurinæ, 136; + _Thylacinus_, 136; _Sarcophilus_, 137; _Dasyurus_, 138; + _Phascologale_, 139; _Sminthopsis_, 139; _Antechinomys_, + 139; _Subfamily_ Myrmecobiinæ, 140; _Myrmecobius_, 140. + _Family_ PERAMELIDÆ, 141; _Perameles_, 142; _Peragale_, 143; + _Chœropus_, 143. + + _Suborder_ DIPROTODONTIA 144 + + _Family_ PHASCOLOMYIDÆ, 144; _Phascolomys_, 145; + _Phascolonus_, 146. _Family_ PHALANGERIDÆ, 147; _Subfamily_ + Tarsipedinæ, 148; _Tarsipes_, 148; _Subfamily_ Phalangerinæ, + 149; _Phalanger_, 149; _Trichosurus_, 150; _Pseudochirus_, + 151; _Petauroides_, 152; _Dactylopsila_, 152; _Petaurus_, + 153; _Gymnobelideus_, 154; _Dromicia_, 154; _Distœchurus_, + 155; _Acrobates_, 155; _Subfamily_ Phascolarctinæ, + 155; _Phascolarctus_, 156. EXTINCT PHALANGEROIDS, 157; + _Thylacoleo_, 157. _Family_ MACROPODIDÆ, 158; _Subfamily_ + Hypsiprymnodontinæ, 162; _Hypsiprymnodon_, 162; + _Triclis_, 162; _Subfamily_ Potoroinæ, 162; _Potorous_, + 163; _Bettongia_, 163; _Caloprymnus_, 164; _Æpyprymnus_, + 164; _Subfamily_ Macropodinæ, 164; _Lagostrophus_, 165; + _Dendrolagus_, 165; _Dorcopsis_, 166; _Lagorchestes_, 166; + _Onychogale_, 166; _Petrogale_, 167; _Macropus_, 167; + Extinct genera, 170. EXTINCT FAMILIES, 171; _Diprotodon_, + 171; _Nototherium_, 171. + + CHAPTER VII + + THE SUBCLASS EUTHERIA AND THE ORDER EDENTATA 173 + + General characters and classification of Eutheria, 173. + + ORDER EDENTATA 176 + + _Family_ BRADYPODIDÆ, 179; _Bradypus_, 181; _Cholœpus_, 182; + _Nothropus_, 183. _Family_ MEGATHERIIDÆ, 183; _Megatherium_, + 185; _Scelidotherium_ and _Mylodon_, 188; _Promegatherium_, + 189. _Family_ MYRMECOPHAGIDÆ, 190; _Myrmecophaga_, 190; + _Tamandua_, 192; _Cycloturus_, 193. _Family_ DASYPODIDÆ, + 194; _Subfamily_ Chlamydophorinæ, 196; _Chlamydophorus_, + 196; _Subfamily_ Dasypodinæ, 197; _Dasypus_, 197; _Xenurus_, + 198; _Priodon_, 198; _Tolypeutes_, 199; _Subfamily_ + Tatusiinæ, 200; _Tatusia_, 200; Extinct genera, 201. + _Family_ GLYPTODONTIDÆ, 202. _Family_ MANIDÆ, 204; _Manis_, + 204; _Palæomanis_, 208. _Family_ ORYCTEROPODIDÆ, 208; + _Orycteropus_, 208. Bibliography, 211. + + CHAPTER VIII + + THE ORDERS SIRENIA AND CETACEA 212 + + ORDER SIRENIA 212 + + _Family_ MANATIDÆ, 215; _Manatus_, 215. _Family_ HALICORIDÆ, + 220; _Halicore_, 220. _Family_ RHYTINIDÆ, 221; _Rhytina_, + 221. EXTINCT SIRENIANS, 222; _Halitherium_, 222; Other + forms, 223. Bibliography, 224. + + ORDER CETACEA 225 + + _Suborder_ MYSTACOCETI 234 + + _Family_ BALÆNIDÆ, 234; _Balæna_, 236; _Neobalæna_, 241; + _Rhachianectes_, 241; _Megaptera_, 241; _Balænoptera_, 242; + Extinct genera, 245. + + _Suborder_ ARCHÆOCETI 246 + + _Family_ ZEUGLODONTIDÆ, 246; _Zeuglodon_, 246. + + _Suborder_ ODONTOCETI 247 + + _Family_ PHYSETERIDÆ, 247; _Subfamily_ Physeterinæ, 248; + _Physeter_, 248; _Cogia_, 250; Extinct physeteroids, 251; + _Subfamily_ Ziphiinæ, 251; _Hyperoödon_, 252; _Ziphius_, + 254; _Mesoplodon_, 254; _Berardius_, 256; _Choneziphius_, + 257. _Family_ SQUALODONTIDÆ, 257; _Squalodon_, 257. + _Family_ PLATANISTIDÆ, 257; _Platanista_, 258; _Inia_, 259; + _Pontoporia_, 259; Fossil forms, 259. _Family_ DELPHINIDÆ, + 260; _Monodon_, 260; _Delphinapterus_, 262; _Phocæna_, + 263; _Cephalorhynchus_, 266; _Orcella_, 267; Orca, 267; + _Pseudorca_, 268; _Globicephalus_, 268; _Grampus_, 270; + _Feresia_, 270; _Lagenorhynchus_, 270; _Delphinus_, 271; + _Tursiops_, 271; _Prodelphinus_, 271; _Steno_, 271; + _Sotalia_, 272. Bibliography, 272. + + CHAPTER IX + + THE ORDER UNGULATA 273 + + UNGULATA VERA 275 + + _Suborder_ ARTIODACTYLA 275 + + SUINA, 278. _Family_ HIPPOPOTAMIDÆ, 278; _Hippopotamus_, + 278. _Family_ SUIDÆ, 281; _Sus_, 281; _Babirusa_, 287; + _Phacochœrus_, 288. _Family_ DICOTYLIDÆ, 289; _Dicotyles_, + 289; _Hyotherium_, etc., 291. EXTINCT TRANSITIONAL + ARTIODACTYLES, 292; Chœropotamidæ, 292; Anthracotheriidæ, + 292; _Merycopotamus_, 293; Cotylopidæ, 293; Anoplotheriidæ, + 293; Cænotheriidæ, 294; Dichodontidæ, 294. TYLOPODA, 295. + _Family_ CAMELIDÆ, 295; _Camelus_, 296; _Auchenia_, 298; + Extinct Cameloids, 303. TRAGULINA, 305. _Family_ TRAGULIDÆ, + 305; _Tragulus_, 305; _Dorcatherium_, 306; Extinct + Traguloids, 306. PECORA, 307; Antlers, 308; Horns, 310; + Teeth, 310; Stomach, 312. _Family_ CERVIDÆ, 313; _Subfamily_ + Moschinæ, 314; _Moschus_, 314; _Subfamily_ Cervinæ, 316; + Plesiometacarpalia, 316; _Cervulus_, 316; _Elaphodus_, + 318; _Cervus_, 319; Telemetacarpalia, 323; _Rangifer_, + 324; _Alces_, 326; _Cervalces_, 327; _Capreolus_, 327; + _Hydropotes_, 328; _Cariacus_, 329; _Pudua_, 330; Extinct + genera, 330. _Family_ GIRAFFIDÆ, 330; _Giraffa_, 331; + Allied extinct types, 332. _Family_ ANTILOCAPRIDÆ, 333; + _Antilocapra_, 333. _Family_ BOVIDÆ, 334; _Alcelaphus_, 334; + _Connochætes_, 336; _Cephalophus_, 338; _Tetraceros_, 338; + _Neotragus_, 338; _Nanotragus_, 339; _Pelea_, 339; _Cobus_, + 339; _Cervicapra_, 340; _Antilope_, 340; _Æpyceros_, + 341; _Saiga_, 341; _Pantholops_, 341; _Gazella_, 341; + _Hippotragus_, 343; _Oryx_, 343; _Addax_, 345; _Boselaphus_, + 345; _Tragelaphus_, 346; _Strepsiceros_, 347; _Oreas_, 348; + Extinct types, 348; _Rupicapra_, 349; _Nemorhædus_, 350; + _Haploceros_, 351; _Budorcas_, 351; _Capra_, 352; _Ovis_, + 354; _Ovibos_, 357; _Bos_, 360. + + _Suborder_ PERISSODACTYLA 368 + + _Family_ TAPIRIDÆ, 370; _Tapirus_, 370; _Palæotapirus_, 373. + _Family_ LOPHIODONTIDÆ, 373. _Family_ PALÆOTHERIIDÆ, 375. + _Family_ EQUIDÆ, 376; _Protohippus_, 380; _Hipparion_, 380; + _Equus_, 381. _Family_ RHINOCEROTIDÆ, 402; _Rhinoceros_, + 402; Extinct types, 411. _Families_ LAMBDOTHERIIDÆ, + CHALICOTHERIIDÆ, and TITANOTHERIIDÆ, 412. _Family_ + MACRAUCHENIIDÆ, 414. _Family_ PROTEROTHERIIDÆ, 414. + + SUBUNGULATA 414 + + _Suborder_ HYRACOIDEA 415 + + _Family_ HYRACIDÆ, 415; _Hyrax_, 417; _Dendrohyrax_, 418. + + _Suborder_ PROBOSCIDEA 418 + + _Family_ ELEPHANTIDÆ, 423; _Elephas_, 424; _Mastodon_, 431. + _Family_ DINOTHERIIDÆ, 435; _Dinotherium_, 435. + + _Suborder_ AMBLYPODA 436 + + _Uintatherium_, 436; _Coryphodon_, 437. + + _Suborder_ CONDYLARTHRA 438 + + _Suborder_ TOXODONTIA 439 + + _Nesodon_, 439; _Toxodon_, 439; _Typotherium_, 440. + + _Group_ TILLODONTIA 441 + + Bibliography of Ungulates 442 + + CHAPTER X + + THE ORDER RODENTIA 443 + + _Suborder_ SIMPLICIDENTATA 448 + + _Section_ SCIUROMORPHA, 448. _Family_ ANOMALURIDÆ, 449; + _Anomalurus_, 449. _Family_ SCIURIDÆ, 450; _Sciurus_, + 450; _Rhithrosciurus_, 452; _Xerus_, 452; _Tamias_, + 452; _Pteromys_ and _Sciuropterus_, 453; _Eupetaurus_, + 454; Extinct genera, 454; _Arctomys_, 454; _Cynomys_, + 455; _Spermophilus_, 456; Extinct genera, 457. _Family_ + HAPLODONTIDÆ, 457; _Haplodon_, 457. _Family_ CASTORIDÆ, + 457; _Castor_, 457. _Section_ MYOMORPHA, 459. _Family_ + MYOXIDÆ, 459; _Myoxus_, 459; _Eliomys_, 459; _Graphiurus_, + 459; _Claviglis_, 460; _Muscardinus_, 460. _Family_ + LOPHIOMYIDÆ, 460; _Lophiomys_, 460. _Family_ MURIDÆ, 461; + _Hydromys_, 461; _Xeromys_, 461; _Platacanthomys_, 462; + _Gerbillus_, 462; _Pachyuromys_, 462; _Mystromys_, 462; + _Otomys_ and _Dasymys_, 462; _Malacomys_, 462; _Phlœomys_, + 462; _Dendromys_, 463; _Cricetus_, 463; _Holochilus_, + 464; _Sigmodon_, 464; _Rhithrodon_ and _Ochetodon_, + 464; _Neotoma_, 464; _Hypogeomys_, 465; _Nesomys_, 465; + _Brachytarsomys_, 465; _Hallomys_, 465; _Eliurus_, 465; + _Phenacomys_, 466; _Arvicola_, 466; _Synaptomys_, 467; + _Myodes_, 467; _Cuniculus_, 470; _Fiber_, 470; _Neofiber_, + 472; _Ellobius_, 472; _Siphneus_, 472; _Deomys_, 473; + _Mus_, 473; _Nesocia_, 475; _Golunda_, 476; _Uromys_, + 476; _Chiruromys_, 476; _Hapalotis_, 476; _Mastacomys_, + 476; _Acanthomys_, 476; _Echinothrix_, 477; _Typhlomys_, + 477; _Cricetomys_ and _Saccostomus_, 477; _Pithechirus_, + 477. _Family_ SPALACIDÆ, 477; _Spalax_, 477; _Rhizomys_, + 477; _Bathyergus_, 478; _Georychus_ and _Myoscalops_, + 478; _Heterocephalus_, 478. _Family_ GEOMYIDÆ, 478; + _Geomys_, 478; _Thomomys_, 478; _Dipodomys_, 479; + _Perognathus_ and _Heteromys_, 479. _Family_ DIPODIDÆ, + 479; _Sminthus_, 479; _Zapus_, 480; _Dipus_, 480; + _Alactaga_, 480; _Platycercomys_, 480; _Pedetes_, 480. + _Section_ HYSTRICOMORPHA, 480. _Family_ OCTODONTIDÆ, + 480. _Ctenodactylus_, 481; _Pectinator_, 481; _Octodon_, + 481; _Habrocoma_, 482; _Schizodon_, 482; _Ctenomys_, + 482; _Spalacopus_, 482; _Petromys_, 482; _Myopotamus_, + 482; _Capromys_, 482; _Aulacodus_, 483; _Plagiodon_, + 483; _Loncheres_ and _Echinomys_, 483; _Mesomys_, 483; + _Dactylomys_, 483; _Cercomys_, 483; _Carterodon_, 484; + Fossil forms, 484. _Family_ THERIDOMYIDÆ, 484. _Family_ + HYSTRICIDÆ, 484; _Erethizon_, 484; _Synetheres_, 485; + _Chætomys_, 486; _Hystrix_, 486; _Atherura_, 487; _Trichys_, + 487. _Family_ CHINCHILLIDÆ, 487; _Chinchilla_, 487; + _Lagidium_ and _Lagostomus_, 488; Extinct genera, 488. + _Family_ CASTOROIDIDÆ, 488; _Castoroides_, 488. _Family_ + DASYPROCTIDÆ, 488; _Dasyprocta_, 488; _Cælogenys_, 489. + _Family_ DINOMYIDÆ, 489; _Dinomys_, 489. _Family_ CAVIIDÆ, + 489; _Cavia_, 489; _Dolichotis_, 490; _Hydrochœrus_, 490; + Extinct genera, 491. + + _Suborder_ DUPLICIDENTATA 491 + + _Family_ LAGOMYIDÆ, 491; _Lagomys_, 491. _Family_ LEPORIDÆ, + 492; _Lepus_, 492. + + CHAPTER XI + + THE ORDER CARNIVORA 496 + + _Suborder_ CARNIVORA VERA 497 + + _Section_ ÆLUROIDEA, 501. _Family_ FELIDÆ, 502; _Felis_, + 502; _Cynælurus_, 523; Extinct genera, 523. _Family_ + VIVERRIDÆ, 525; _Cryptoprocta_, 525; _Viverra_, 526; + _Fossa_, 527; _Genetta_, 528; _Prionodon_, 530; _Poiana_, + 531; _Paradoxurus_, 532; _Arctogale_, 533; _Hemigale_, + 533; _Arctictis_, 534; _Nandinia_, 534; _Cynogale_, 534; + _Herpestes_, 535; _Helogale_, 537; _Bdeogale_, 537; + _Cynictis_, 537; _Rhinogale_, 537; _Crossarchus_, 537; + _Suricata_, 538; _Galidictis_, _Galidea_, and _Hemigalidea_, + 538; _Eupleres_, 538; Extinct genera, 539. _Family_ + PROTELEIDÆ, 539; _Proteles_, 539. _Family_ HYÆNIDÆ, 540; + _Hyæna_, 540. _Section_ CYNOIDEA, 544. _Family_ CANIDÆ, 544; + _Canis_, 546; _Lycaon_, 553; _Icticyon_, 553; _Otocyon_, + 554; Extinct genera, 555. _Section_ ARCTOIDEA, 556. _Family_ + URSIDÆ, 557; _Ursus_, 557; _Melursus_, 560; _Æluropus_, 560; + Extinct genera, 561. _Family_ PROCYONIDÆ, 562; _Ælurus_, + 562; _Procyon_, 564; _Bassaris_, 566; _Bassaricyon_, 566; + _Nasua_, 566; _Cercoleptes_, 567. _Family_ MUSTELIDÆ, 567; + _Lutra_, 567; Extinct Otters, 570; _Latax_, 570; _Mephitis_, + 572; _Conepatus_, 574; _Arctonyx_, 574; _Mydaus_, 575; + _Meles_, 575; _Taxidea_, 576; _Mellivora_, 576; _Helictis_, + 578; _Ictonyx_, 579; _Galictis_, 579; _Mustela_, 579; + Extinct Mustelines, 590; _Pœcilogale_, 590; _Lyncodon_, 590; + _Gulo_, 591. + + _Suborder_ PINNIPEDIA 592 + + _Family_ OTARIIDÆ, 593; _Otaria_, 593. _Family_ TRICHECHIDÆ, + 596; _Trichechus_, 597. _Family_ PHOCIDÆ, 600; _Halichœrus_, + 601; _Phoca_, 601; _Monachus_, 604; _Ogmorhinus_, 605; + _Lobodon_, 605; _Pœcilophoca_, 605; _Ommatophoca_, 605; + _Cystophora_, 605; _Macrorhinus_, 606; Extinct seals, 606. + + _Suborder_ CREODONTA 606 + + _Hyænodontidæ_, 608; _Proviverridæ_, 608; _Arctocyonidæ_ and + _Mesonychidæ_, 609. + + CHAPTER XII + + THE ORDER INSECTIVORA 610 + + _Suborder_ DERMOPTERA 614 + + _Family_ GALEOPITHECIDÆ, 614; _Galeopithecus_, 614. + + _Suborder_ INSECTIVORA VERA 616 + + _Family_ TUPAIIDÆ, 617; _Tupaia_, 617; _Ptilocercus_, + 618; Extinct genera, 618. _Family_ MACROSCELIDIDÆ, 618; + _Macroscelides_, 618; _Rhynchocyon_, 618. _Family_ + ERINACEIDÆ, 619; _Gymnura_, 619; _Erinaceus_, 620; + Extinct genera, 621; _Family_ SORICIDÆ, 621; _Sorex_, + 622; _Soriculus_, 624; _Notiosorex_, 624; _Blarina_, 624; + _Crossopus_, 625; _Myosorex_, 625; _Crocidura_, 626; + _Diplomesodon_, 626; _Anurosorex_, 626; _Chimarrogale_, 626; + _Nectogale_, 627; Fossil Soricidæ, 627. _Family_ TALPIDÆ, + 628; _Myogale_, 628; _Urotrichus_, 629; _Uropsilus_, + 629; _Scalops_, 630; _Scapanus_, 630; _Condylura_, 630; + _Scaptonyx_, 630; _Talpa_, 630; Extinct genera, 634. + _Family_ ADAPISORICIDÆ, 634. _Family_ POTAMOGALIDÆ, 634; + _Potamogale_, 635; _Geogale_, 635. _Family_ SOLENODONTIDÆ, + 635; _Solenodon_, 636; _Centetes_, 637; _Hemicentetes_, + 637; _Ericulus_, 638; _Microgale_, 638; _Oryzorictes_, 638; + _Chrysochloris_, 639. EXTINCT TYPES, 640. Bibliography, 640. + + CHAPTER XIII + + THE ORDER CHIROPTERA 641 + + _Suborder_ MEGACHIROPTERA 650 + + _Family_ PTEROPODIDÆ, 650; _Epomophorus_, 650; _Pteropus_, + 651; _Xantharpyia_, 652; _Boncia_, 653; _Cynopterus_, 653; + _Harpyia_, 653; _Cephalotes_, 653; _Pteralopex_, 654; + _Notopteris_, 654; _Eonycteris_, 654; _Carponycteris_ and + _Melonycteris_, 654; _Nesonycteris_, 655; _Callinycteris_, + 655; _Trygenycteris_, 655. + + _Suborder_ MICROCHIROPTERA 655 + + _Section_ VESPERTILIONINA, 655. _Family_ RHINOLOPHIDÆ, + 656; _Rhinolophus_, 656; _Hipposiderus_, 657; _Anthops_, + 657; _Rhinonycteris_ and _Triænops_, 658; _Cœlops_, 658; + _Megaderma_, 658. _Family_ VESPERTILIONIDÆ, 660; _Plecotus_, + 660; _Synotus_, 661; _Otonycteris_, 661; _Nyctophilus_, 661; + _Antrozous_, 661; _Vesperugo_, 661; _Chalinolobus_, 662; + _Scotophilus_, 662; _Nycticejus_, 663; _Atalapha_, 663; + _Harpyiocephalus_, 663; _Vespertilio_, 663; _Cerivoula_, + 664; _Natalus_, 664; _Miniopterus_, 664; _Thyroptera_, + 665; _Myxopoda_, 665; Fossil Vespertilionidæ, 665. + _Section_ EMBALLONURINA, 666. _Family_ EMBALLONURIDÆ, 666; + _Furipterus_ and _Antorphochilus_, 666; _Emballonura_, 667; + _Coleüra_, 667; _Rhynchonycteris_, 667; _Saccopteryx_, + 667; _Taphozous_, 667; _Diclidurus_, 668; _Noctilio_, + 668; _Rhinopoma_, 669; _Chiromeles_, 669; _Molossus_, + 670; _Nyctinomus_, 670; _Mystacops_, 671. _Family_ + PHYLLOSTOMATIDÆ, 672; _Chilonycteris_, 672; _Mormops_, + 672; _Lonchorhina_, _Otopterus_ and _Dolichophyllum_, 673; + _Vampyrus_, etc., 673; _Desmodus_, 677; _Diphylla_, 678. + + CHAPTER XIV + + THE ORDER PRIMATES 680 + + _Suborder_ LEMUROIDEA 682 + + _Family_ LEMURIDÆ, 683; _Indris_, 684; _Propithecus_, + 684; _Avahis_, 686; _Lemur_, 687; _Hapalemur_, 689; + _Lepidolemur_, 689; _Chirogaleus_, 689; _Galago_, 690; + _Nycticebus_, 691; _Loris_, 692; _Perodicticus_, 693. + _Family_ TARSIIDÆ, 694; _Tarsius_, 694. _Family_ CHIROMYIDÆ, + 694; _Chiromys_, 695. EXTINCT LEMUROIDS, 696. + + _Suborder_ ANTHROPOIDEA 699 + + _Family_ HAPALIDÆ, 709; _Hapale_, 710; _Midas_, 710. + _Family_ CEBIDÆ, 711; _Mycetes_, 711; _Pithecia_, 712; + _Uacaria_, 712; _Callithrix_, 713; _Chrysothrix_, 714; + _Nyctipithecus_, 714; _Ateles_, 715; _Eriodes_, 715; + _Lagothrix_, 716; _Cebus_, 717. _Family_ CERCOPITHECIDÆ, + 718; _Cynocephalus_, 719; _Theropithecus_, 722; + _Cynopithecus_, 722; _Macacus_, 722; _Cercocebus_, 723; + _Cercopithecus_, 724; _Nasalis_, 725; _Semnopithecus_, 726; + _Colobus_, 727; Extinct genera, 727. _Family_ SIMIIDÆ, + 728; _Hylobates_, 728; _Simia_, 731; _Gorilla_, 734; + _Anthropopithecus_, 736. _Family_ HOMINIDÆ, 739; _Homo_, + 740. Classification of the varieties of Man, 743. + + + + +AN INTRODUCTION TO THE STUDY OF MAMMALS LIVING AND EXTINCT + + + + +CHAPTER I + +_INTRODUCTORY REMARKS_ + + +Mammalia (French, _Mammifères_; German, _Säugethiere_) is the name +invented by Linnæus (from the Latin _mamma_), and now commonly used by +zoologists, for one of the five great classes of vertebrated animals, +which, though the best known and undoubtedly the most important group +of the animal kingdom, has never received any generally accepted +vernacular designation in our language. The unity of structure of the +animals composing this class, and their definite demarcation from other +vertebrates, were not recognised until comparatively modern times, +and hence no word was thought of to designate what zoologists now +term a mammal. The nearest equivalents in common use are “beast” and +“quadruped,” both of which, however, cover a different ground, since they +are often used to include the larger four-footed reptiles, and to exclude +certain undoubted mammals, as Man, Bats, and Whales. + +The limits of the class as now understood by zoologists are perfectly +well defined, and, although certain forms still existing on the earth +(but not those mentioned above as excluded by the popular idea) are +of exceedingly aberrant structure, and exhibit several well-marked +characters connecting them with the lower vertebrated groups, common +consent retains them in the class with which the great proportion of +their characters ally them, and hitherto no traces of any species showing +still more divergent or transitional characters have been discovered. +There is thus an interval, not bridged over by any known forms, between +mammals and other vertebrates; although recent discoveries have shown +evidence of a more or less marked affinity between the most generalised +mammals and a peculiar group of extinct reptiles known as the Anomodontia +(or Theromora), which are themselves nearly related to the equally +extinct Labyrinthodont amphibians of the Palæozoic and Mesozoic epochs. + +In the gradual order of evolution of living beings, mammals, taken +altogether, are certainly the highest in organisation, as, with the +possible exception of birds, they were the last to appear on the +earth’s surface. But, as in speaking of all other large and greatly +differentiated groups, this expression must not be understood in too +limited a sense. The tendency to gradual perfection for their particular +station in life, which all groups manifest, leads to various lines of +specialisation, or divergence from the common or general type, which +may or may not take the direction of elevation. A too complex and +sensitive condition of organisation may in some circumstances of life be +disadvantageous, and modification may then take place in a retrograde +direction. Thus in mammals, as in other classes, there are low as well as +high forms, but by any tests that can be applied—especially those based +on the state of development of the central nervous system—it will be seen +that the average exceeds that of any other class; that the class contains +many species far excelling those of any other in perfection of structure, +and especially one form which is unquestionably the culminating point yet +arrived at amongst organised beings. + +With regard to the time of the first appearance of mammals upon +the earth, the geological record is provokingly imperfect. At the +commencement of the Tertiary period they were abundant, and already +modified into most of the leading types at present existing. It was at +one time thought that they first came into being at this date, but the +discovery of more or less fragmentary remains of numerous and generally +small species has revealed the existence of some forms of the class at +various periods throughout almost the whole of the age of the deposition +of the Secondary or Mesozoic rocks. This subject will be reverted to +later on. + +It hardly need be said that mammals are vertebrated animals, and possess +all the characteristics common to the members of that division of the +animal kingdom. They are separated from the _Ichthyopsida_ (fishes and +amphibians), and agree with the _Sauropsida_ (reptiles and birds), in +the possession during their development of an amnion and allantois, and +in never having external branchiæ or gills. They differ from reptiles +and resemble birds in being warm-blooded, and having a heart with four +cavities and a complete double circulation. They differ from both birds +and reptiles in the red corpuscles of the blood being non-nucleated +and, with very few exceptions, circular in outline; in the lungs being +freely suspended in a thoracic cavity, separated from the abdomen by a +complete muscular partition—the diaphragm—which is the principal agent +in inflating the lungs in respiration; in having but one aortic arch, +which curves over the left bronchus; in the skin being more or less +clothed with hair; in the greater perfection of the commissural system of +the cerebral hemispheres, which has either a complete corpus callosum, +or an incomplete one associated with a very large anterior commissure; +in having no syrinx or inferior vocal organ, but a complete larynx at +the upper end of the trachea; in having a mandible of which each ramus +(except in very early developmental conditions) consists of a single bone +on each side, articulating to the squamosal without the intervention of +a quadrate bone; in having a pair of laterally placed occipital condyles +instead of one median one; and in the very obvious character of the +female being provided with mammary glands, by the secretion of which the +young (usually produced alive, although in the lowest forms by means of +externally hatched eggs) are nourished for some time after birth. + +In common with all vertebrated animals, mammals never have more than +two pairs of limbs; as the larger number live ordinarily on the surface +of the earth, in the great majority of the class both pairs are +well-developed and functional, and adapted for terrestrial progression. +Mammals are, however, by no means limited to this situation. Thus some +species spend the greater part of their lives beneath the surface, their +fore limbs being specially modified for burrowing; others, again, are +habitually arboreal, their limbs being fitted for climbing or hanging +to boughs of trees; some are as aerial as birds, the fore limbs being +developed into wings of a special character; while in others which are as +aquatic as fishes, the limbs assume the form of fins or paddles. In many +of the latter the hinder extremities are either completely suppressed, +or present only in a rudimentary state. In no known mammal are the fore +limbs absent. + +The hinder extremity of the axis of the body is usually prolonged into +a tail, which may be a mere pendent appendage, or may be modified to +perform various functions, as grasping boughs in climbing, or even +gathering food, in the case of the prehensile-tailed Monkeys and +Opossums, swimming in the Cetacea, and acting as a flap to drive away +troublesome insects from the skin in the Ungulata. + +The state of development of the young at the time of birth varies greatly +in the different groups. Thus among the Marsupials where there is no +connection during intra-uterine life between the circulatory systems +of the parent and the fœtus, the young are born in an exceedingly +imperfectly developed condition. For their protection the mother, in +a large number of cases, has a special pouch enclosing the mammæ, into +which the young are transferred at birth, and in which they remain till +they are well developed. Among the higher, or Placental types, however, +where a connection exists between the maternal and fœtal circulations +previous to birth, the young are always born in a much more highly +developed state than among the Marsupials, although we meet with great +variations in this respect. In those forms which habitually live in +holes, like many Rodents, the young are always very helpless at birth; +and the same is also true of many of the Carnivora, which are well able +to defend their young from attack. In the great order of Ungulate, +or Hoofed Mammals, where in the majority of cases defence from foes +depends upon fleetness of foot, or upon huge corporeal bulk, the young +are born in a very highly developed condition, and are able almost at +once to run by the side of the parent. This state of relative maturity +at birth reaches its highest development in the Cetacea, where it is +evidently associated with the peculiar conditions under which these +animals pass their existence. In the Primates, however, we again find +the young produced in a more or less helpless condition, and requiring +a long period before they attain their full development, this being +more especially the case with those higher forms which approximate in +structure to man. + +In point of size mammals vary to a greater extent than the existing +members of any one class of animals, and include the largest living +inhabitants of the earth. The extremes of size are marked on the one +hand by the whale known as Sibbald’s Rorqual, which attains a length of +eighty feet and a weight of nearly as many tons, and on the other by the +Pigmy-Shrew and the minute Harvest-mouse, which can climb a stem of wheat. + +Of all the living creatures inhabiting our globe, mammals are by far +the most important in their economic uses, since, in addition to being +the only animals capable of labour for human benefit, they furnish the +greater portion of the animal food of many races of man, and likewise a +large amount of their clothing. In these respects the Ungulates hold the +first place. + +As regards employment for labour, with the exception of the Dogs used +for sleighing by the Esquimaux, and those which among some European +nations draw light carts, all the mammals in general use are Ungulates. +Of the first importance are the Horses and Asses, which are employed +as beasts of draught or burden over nearly the whole globe. Among many +nations, however, cattle, as represented by the true Oxen, the Buffalos, +and the Yaks of Tibet, occupy a still more important position, while in +the highlands of Tibet, Sheep are largely used for carrying burdens. In +other regions, again, the place of the Horse and the Ass is taken by the +Camels, which are peculiarly fitted for traversing parched and arid +deserts, while in the Andes we find the Llamas serving the same office. +In Lapland and other parts of the northern regions the Reindeer is the +main agent employed in draught. Lastly, we must not omit to mention the +Indian Elephant, which, from its vast strength, is so useful in transport +through the wilder parts of its native country. + +As regards food, we again find the Ungulates, and more especially the +Artiodactyle division, taking the foremost place; and in this connection +we have only to mention, among animals kept in a domestic condition, +Swine, Cattle, Sheep, and Goats—the three latter affording not only their +flesh, but also milk and its resulting cheese and butter. To many races, +however, Mares and Camels are the chief milk producers, while the Laps +make use of the milk of the Reindeer. The Rodents, as represented by +Hares and Rabbits, occupy a minor position as furnishers of food. + +In relation to clothing, the Ungulates are likewise of paramount +importance, as exemplified by the wool of the Sheep, which is so valuable +on account of its peculiar property of felting. Furs, however, are +mostly yielded by mammals of other orders, among which the Fur-seals are +perhaps the most important at the present day. Many other Carnivores +yield valuable furs, among which may be mentioned Bears, Foxes, Raccoons, +Skunks, Minks, Otters, and Ermines. Of less importance are certain +Rodents, such as the Squirrels, Rabbits, Hares, etc., while the hair of +the Beaver was formerly much sought after for the manufacture of hats. +Returning to the Ungulates, we may notice the importance of horse-hair, +the employment of camel’s hair for brushes, and the many uses of the +bristles of the pig. Some of the Monkeys yield fur which has been +extensively used. Leather, again, is almost exclusively supplied by +mammals, and mainly by the Ungulates. + +Three other important products, namely horn, buck’s-horn, and ivory, are +likewise obtained solely from the same great order. Horn, as we shall +notice in the sequel, is the sheath covering the bony horn-cores of the +Oxen, while buck’s-horn is the commercial term applied to the antlers of +the Deer, which are largely used for knife-handles and other purposes. +True ivory is the product of the two species of Elephant; but other kinds +of ivory are obtained from the teeth of the Sperm Whale and the tusks +of the Walrus and Hippopotamus, the latter kind having been extensively +employed some years ago for artificial teeth. For many purposes the place +of ivory is taken by bone, this being mostly obtained from Ungulates. +The bones of Camels are of an especially firm texture and good colour, +and are largely employed in India for inlaying. Other important uses of +bones are in the form of bone-dust as manure, and also as a source of +phosphoric acid. The horns of the African Rhinoceros and the hide of the +Hippopotamus are occasionally manufactured into small canes or whips. +Horns and hoofs are also largely employed in the manufacture of glue. + +Formerly the so-called whalebone, or more properly baleen, was much +used, especially to form the ribs of umbrellas and in stiffening ladies’ +apparel, but the gradual destruction of the Right Whales, its only source +of supply, has largely restricted its use of late years. + +The Cetacea are also of great economical importance from the abundance +of oil yielded by the thick layer of blubber underlying the skin. +Large quantities of valuable oil are also furnished by the Walrus and +the Seals. Spermaceti, which was at one time extensively used in the +manufacture of candles, is obtained from a large cavity in the head +of the Sperm Whale or Cachalot, and also from the _Hyperoödon_ or +Bottle-nosed Whale. + +The nature of ambergris, a peculiar substance found floating on the +surface of the sea and employed in perfumery, was long a matter of +controversy; but it appears to be an intestinal concretion of the Sperm +Whale. Other substances of more importance to the perfumer are musk, the +product of the Musk-Deer of the Himalaya, and civet, which is obtained +from the so-called Civet Cat and other allied Carnivores. A secretion of +the Beaver has also been used in perfumery and in medicine. + + + + +CHAPTER II + +GENERAL ANATOMICAL CHARACTERS + + +I. TEGUMENTARY STRUCTURES + +_Hair._—The external surface of the greater number of members of the +class is thickly clothed with a peculiarly modified form of epidermis, +commonly called hair. This consists of hard, elongated, slender, +cylindrical or tapering, filiform, unbranched masses of epidermic +material, growing from a short papilla sunk at the bottom of a follicle +in the derm or true skin. Such hairs upon different parts of the same +animal, or upon different animals, assume various forms, and are of +various sizes and degrees of rigidity,—as seen in the delicate soft +velvety fur of the Mole, the stiff bristles of the Pig, and the spines +of the Hedgehog and Porcupine, all modifications of the same structures. +Each hair is composed usually of a cellular pithy internal portion, +containing much air, and a denser or more horny cortical part. In some +animals, as Deer, the substance of the hair is almost entirely composed +of the medullary or cellular substance, and it is consequently very +easily broken; in others the horny part prevails almost exclusively, as +in the bristles of the Wild Boar. In the Three-toed Sloth (_Bradypus_) +the hairs have a central horny axis and a pithy exterior. Though +generally nearly smooth, or but slightly scaly, the surface of some hairs +is strongly imbricated, notably so in some Bats; while in the Two-toed +Sloth (_Cholœpus_) the hairs are longitudinally grooved or fluted. +Though usually more or less cylindrical or circular in section, hairs +are often elliptical or flattened, as in the curly-haired races of men, +the terminal portion of the hair of Moles and Shrews, and conspicuously +in the spines of the Rodents _Xerus_ and _Platacanthomys_. Hair having +a property of mutual cohesion or “felting,” which depends upon a +roughened scaly surface and a tendency to curl, as in domestic Sheep (in +which animal this property has been especially cultivated by selective +breeding), is called “wool.” + +In a large number of mammals hairs of one kind only are scattered pretty +evenly over the surface; but in many there are two kinds, one longer, +stiffer, and alone appearing on the surface, and the other shorter, +finer, and softer, constituting the under fur, analogous to the down +of birds. This under fur, or _pashm_ as it is called by the natives +of Kashmir, is especially abundant in the mammals inhabiting the cold +plateau of Tibet and the adjacent regions. In many cases hairs of a +different character from those of the general surface grow in special +regions, forming ridges or tufts on the median dorsal or ventral surface +or elsewhere. The tail is very often completed in this way by variously +disposed elongated hairs. The margins of the eyelids are almost always +furnished with a special row of stiffish hairs, called _cilia_ or +eyelashes; and in most mammals specially modified hairs, constituting +the _vibrissæ_ or whiskers, and endowed, through the abundant nerve +supply of their basal papillæ, with special tactile powers, grow from +the lips and cheeks. In some mammals the hairy covering is partial and +limited to particular regions; in others, as the Hippopotamus and the +Sirenia, though scattered over the whole surface, it is extremely short +and scanty; but in none is it reduced to so great an extent as in the +Cetacea, in which it is limited to a few small bristles confined to the +neighbourhood of the lips and nostrils, and often only present in the +young or even fœtal condition. + +Some kinds of hairs, as those of the mane and tail of the Horse, appear +to persist throughout the lifetime of the animal; but more generally, +as in the case of the body hair of the same animal, they are shed and +renewed periodically, generally annually. Many mammals have a longer +hairy coat in winter, which is shed as summer comes on; and some few, +which inhabit countries covered in winter with snow, as the Arctic Fox, +Variable Hare, and Ermine, undergo a complete change of colour in the +two seasons, being white in winter, and gray or brown in summer. The +several species of Cape Mole (_Chrysochloris_), the Desmans or Water +Moles (_Myogale_), and _Potamogale velox_, are remarkable as being the +only mammals whose hair reflects those iridescent tints so common in the +feathers of tropical birds. + +The principal and most obvious purpose of the hairy covering is to +protect the skin against external influences, especially cold and damp. +Its function in the hairless Cetacea is supplied by the specially +modified and thickened layer of adipose tissue beneath the skin, called +“blubber.” + +_Colour._—From the consideration of hair we are easily led to that of +colour. As a general rule, bright and primary colours are absent in +the class; but among the Baboons we find brilliant patches of scarlet +or blue on some of the bare portions of the body, and one of the South +American Monkeys (_Brachyurus_) has its whole face of a bright crimson. +The most general colours are various shades of gray, brown, and tawny, +with a frequent tendency to whiteness of the ventral surface of the +body; but among the Squirrels, and more especially those provided with +a parachute for flying, we find brilliant russets, passing into orange +and red. Dark brown or black is also not very uncommon, as in the Bears +and the Sable Antelope of South Africa. Entirely white mammals are rare, +and mostly characteristic of the polar regions, or of countries having +a long and snowy winter. An entirely white Bat (_Diclidurus albus_) +occurs, however, in South America. In the large majority of mammals that +exhibit a varied coloration, the upper and most exposed parts of the +surface present the richest and darkest colours, the under parts being +pale or often quite white. The Ratels, Gluttons, _Ælurus_, Hamsters, +and some others are exceptions to this rule. A large number of mammals +having a ground colour of gray, tawny, or dun are marked by stripes or +spots, which are generally of a darker hue than the ground colour, as in +many Carnivora, but more rarely are lighter, as in the Fallow and Axis +Deer and several species of Antelope. These stripes very generally run +transversely to the axis of the body, as in the Tasmanian Thylacine, the +Tiger, and the Zebra; but they may be longitudinal, as in several of +the Civet family. There has been considerable discussion as to whether +the striped or the spotted is the more primitive type of coloration; +but no very conclusive arguments have been brought forward in favour of +either view. It is, however, manifest that in several groups of mammals +there is a tendency to lose the spots, and more rarely the stripes, and +to assume a uniform colour. Thus the young of nearly all the species of +Deer are spotted, whereas the adults of only the Fallow and Axis Deer +are so marked. The same is true of most of the Pigs; and the young of +the Malayan and American Tapirs are marked by light-coloured stripes and +spots on a dark ground. In like manner the young of the Lion and the +Puma exhibit distinct spots which disappear with advancing age. In most +of our domestic horses of various shades of bay and brown we may detect +“dappling” on the under hair when the outer coat has been removed, which +is not apparent on the surface of the latter. Many varieties of the Ass +and the Horse also exhibit a tendency to the presence of stripes on the +legs, which would seem to indicate a descent from a striped Zebra-like +type. + +A peculiar feature, which is, however, common to many other groups of +animals, is the tendency to what is known as melanism, or the production +of black or dark individuals or races of particular species, due to an +excess of pigment in the skin and hair. Thus we may have black Leopards +and Jaguars, black Wolves, and black Rabbits. + +The opposite to melanism, and of more frequent occurrence, is albinism—a +condition in which the pigment or colouring matter usually present in +the tissues constituting the external coverings of the body, and which +gives them their characteristic hue, is absent. When it occurs the hair +is of an opaque white, the claws, hoofs, etc., of a pale horn-colour, +and the skin and eyes pink, in consequence of the colour of the blood +which circulates through them being no longer concealed by the stronger +hues of the pigments. An animal in this condition is called an _albino_. +In complete albinism there is a total absence of pigment throughout the +system. This condition occurs occasionally as an individual peculiarity +among wild animals of many kinds; but it has never been perpetuated among +them in distinct races or species. The disadvantage of absence of pigment +in the eye, causing a certain amount of intolerance of light, is probably +sufficient to account for this. Several races of true albinos, as White +Ferrets, Rabbits, Rats, and Mice, have, however, been established under +the protection of man, and in them this abnormal condition is propagated +from generation to generation. + +Partial albinism—a condition in which the absence of pigment is limited +to portions of the surface, or, at all events, does not extend to the +eyes—is much more common as an individual variation both in domestic and +in wild animals. It is possible that the artificial conditions incident +to domestication increase the tendency to its occurrence; but, whether +this be so or not, it certainly becomes perpetuated more frequently among +domesticated than among wild animals. This may be accounted for partly +by its proving of no disadvantage to them, and partly by the frequent +selection by man of animals of such colour in preference to others. The +result is that there is no completely domestic animal of which white +races do not exist. On the other hand, to most wild animals even partial +albinism seems to be a disadvantage in the struggle for existence, since, +except in the case of species inhabiting lands continually covered with +snow, it renders them more conspicuous objects both to their enemies and +their prey, and hence it is rarely perpetuated. In northern regions, +however, a large proportion of species are regularly and normally of a +white colour, either, as the Polar Bear, all the year through, or, as the +Ermine or Stoat, Arctic Fox, and Alpine Hare, during the winter season. +The coloration in these cases is obviously protective, as it is also to a +great extent in many other instances throughout the class. + +Among conspicuously coloured mammals, it has been observed that the +vertical black and tawny stripes of the Tiger harmonise so well with the +brown and green grasses of its native jungle as to render the animal +almost invisible when lying among them; while the dappled hide of the +Giraffe is said to agree equally well with the chequered splashes of +light and shade in the clumps of tall mimosas among which it feeds. The +uniformly tawny hue of the Lion accords well with the prevailing tint +of its native desert; and any one who has seen an Elephant or Buffalo in +the deep shades of an Indian forest will realise how perfectly adapted is +their dull, slaty colour to concealment in such a spot. The dun colour +of the Wild Ass of India is equally well suited to the sandy deserts +of Kutch; it is also stated that the brilliant stripes of the Zebras +of Africa are arranged in such proportion as exactly to match the pale +tint which arid ground possesses when seen by moonlight.[1] The most +remarkable instance of protective coloration is, however, to be found in +the Sloths of South America, in which the coarse gray hairs so closely +resemble a mass of lichenous growth that it is almost impossible to +distinguish these animals when at rest from the gnarled and lichen-clad +boughs from which they suspend themselves. This resemblance is increased +by the fact that the hairs actually develop a growth of lichens upon +themselves. That the sombre coloration of these animals has been produced +to harmonise with their present surroundings seems to be evident by the +circumstance that when the long hair is plucked off the under fur is seen +to present a bold alternation of black and yellow stripes, which may +probably be regarded as the original primitive coloration of this group. + +_Scales, etc._—True scales, or flat imbricated plates of horny material, +covering the greater part of the body, so frequently occurring in +reptiles, are found only in one family of mammals, the _Manidæ_ or +Pangolins; but these are also associated with hairs growing from the +intervals between the scales, or on the parts of the skin not covered +by them. Similarly, imbricated epidermic productions form the covering +of the under surface of the tail of the flying Rodents of the genus +_Anomalurus_; and flat scutes, with the edges in apposition, and not +overlaid, clothe both surfaces of the tail of the Beaver, Rats, and +others of the same order, and also of some Insectivores and Marsupials. +The Armadillos alone have an ossified exoskeleton, composed of plates +of true bony tissue, developed in the derm or corium, and covered with +scutes of horny epidermis. Other epidermic appendages are the horns of +Ruminants and Rhinoceroses,—the former being elongated, tapering, hollow +caps of hardened epidermis of fibrillated structure, fitting on and +growing from conical projections of the frontal bone, and always arranged +in pairs, while the latter are of similar structure, but solid and +without any internal bony support, and (in all existing species) situated +in the median line. Callosities, or bare patches covered with hardened +and thickened epidermis, are found covering the pads under the soles of +the feet and undersurfaces of the toes of nearly all mammals, upon the +ischial tuberosities of many Apes, the sternum of Camels, on the inner +side of the limbs of the _Equidæ_, the grasping under surface of the +tail of the prehensile-tailed Monkeys, etc. The greater part of the skin +of both species of one-horned Asiatic Rhinoceros is immensely thickened +and stiffened by increase of the tissue both of the derm and epiderm, +constituting the well-known jointed “armour-plated” hide of those animals. + +_Nails, Claws, and Hoofs._—With very few exceptions, the terminal +extremities of the digits of both limbs are more or less protected or +armed by epidermic plates or sheaths, constituting the various forms +of nails, claws, or hoofs. These are wanting in the Cetacea alone. A +perforated spur, with a special secreting gland in connection with it, +is found attached to the hind leg of the males of the three genera of +Monotremata, _Ornithorhynchus_, _Proechidna_, and _Echidna_. + +_Odour-secreting Glands._—Besides the universally distributed sebaceous +glands connected with the pilose system, most mammals have special glands +situated in modified portions of the integument, often involuted to form +a shallow recess or a deep sac with a narrow opening, situated in various +parts of the surface of the body, and secreting odorous substances, +by the aid of which individuals appear to recognise one another, and +probably affording the principal means by which wild animals are able +to become aware of the presence of other members of the species, even +at great distances. Although the commencement of the modifications of +portions of the external covering for the formation of special secretions +may be at present difficult to understand, the principle of natural +selection will readily explain how such organs become fixed and gradually +increase in development in any species, especially as there would +probably be a corresponding modification and increased sensibility of the +olfactory organs. Such individuals as by the intensity and peculiarity +of their scent had greater power of attracting the opposite sex would +certainly be those most likely to leave descendants to inherit and in +their turn propagate the modification. + +To this group of structures belong the suborbital gland or “crumen” of +Antelopes and Deer, the frontal gland of the Muntjac and of Bats of +the genus _Hipposiderus_, the submental gland of the Chevrotains and +of _Taphozous_ and some other Bats, the post-auditory follicle of the +Chamois, the temporal gland of the Elephant, the lateral glands of the +Musk-Shrew, the dorsal gland of the Peccary, the inguinal glands of +Antelopes, the preputial glands of the Musk-Deer and Beaver (already +alluded to in connection with the use made of their powerfully odorous +secretion in medicine and perfumery) and also of the Swine and Hare, +the anal glands of Carnivora, the perineal gland of the Civet (also of +commercial value), the caudal glands of the Fox and Goat, the gland on +the humeral membrane of Bats of the genus _Saccopteryx_, the post-digital +gland of the Rhinoceros, the interdigital glands of the Sheep and many +Ruminants, and numerous others. In some of these cases the glands are +peculiar to, or more largely developed in, the male; in others they are +found equally developed in both sexes. + + +II. DENTAL SYSTEM + +The dental system of mammals may be considered rather more in detail +than space permits for some other portions of their structure, not only +on account of the important part it plays in the economy of the animals +of this class, but also for its interest to zoologists as an aid in the +classification and identification of species. Owing to the imperishable +nature of their tissues, teeth are preserved for an indefinite time, and +in the case of extinct species frequently offer the only indications +available from which to derive an idea of the characters, affinities, +and habits of the animals to which they once belonged. Hence even +their smallest modifications have received great attention from +comparative anatomists, and they have formed the subject of many special +monographs.[2] + +Teeth are present in nearly all mammals, and are applied to various +purposes. They are, however, mainly subservient to the function of +alimentation, being used either in procuring food, by seizing and +killing living prey or gathering and biting off portions of vegetable +material, and more indirectly in tearing or cutting through the hard +protective coverings of food substances, as the husks and shells of nuts, +or in pounding, crushing, or otherwise mechanically dividing the solid +materials before swallowing, so as to prepare them for digestion in the +stomach. Certain teeth are also in many animals most efficient weapons of +offence and defence, and for this purpose alone, quite irrespective of +subserviency to the digestive process, are they developed in the male sex +of many herbivorous animals, in the females of which they are absent or +rudimentary. + +Teeth belong essentially to the tegumentary or dermal system of organs, +and, as is well seen in the lower vertebrates, pass by almost insensible +gradations into the hardened spines and scutes formed upon the integument +covering the outer surface of the body; but in mammals they are more +specialised in structure and limited in locality. In this class they +are developed only in the gums or fibro-mucous membrane covering the +alveolar borders of the upper and lower jaws, or, in other words, the +premaxillary and maxillary bones and the mandible. In the process of +development, for the purpose of giving them that support which is needful +for the performance of their functions, they almost always become +implanted in the bone,—the osseous tissue growing up and moulding itself +around the lengthening root of the tooth, so that ultimately they become +apparently parts of the skeleton. In no mammal, however, does ankylosis +or bony union between the tooth and jaw normally take place, as in +many fishes and reptiles,—a vascular layer of connective tissue, the +alveolo-dental membrane, always intervening.[3] The presence of two or +more roots, frequently met with in the cheek-teeth of mammals, implanted +in corresponding distinct sockets of the jaw, is now peculiar to animals +of this class.[4] + +_Structure._—The greater number of mammalian teeth when fully formed are +not simple and homogeneous in structure, but are composed of several +distinct tissues, which are enumerated below. + +The _pulp_, a soft substance, consisting of a very delicate gelatinous +connective tissue, in which numerous cells are imbedded, and abundantly +supplied with blood-vessels and nerves, constitutes the central axis +of all the basal part of the tooth, and affords the means by which the +vitality of the whole is preserved. The nerves which pass into the pulp +and endow the tooth with sensibility are branches of the fifth pair of +cranial nerves. The pulp occupies a larger relative space, and performs +a more important purpose, in the young growing tooth than afterwards, as +by the calcification and conversion of its outer layers the principal +hard constituent of the tooth, the dentine, is formed. In teeth which +have ceased to grow the pulp occupies a comparatively small space, which +in the dried tooth is called the pulp-cavity. This communicates with the +external surface of the tooth by a small aperture at the apex of the +root, through which the branches of the blood-vessels and nerves, by +which the tooth receives its nutrition and sensitiveness, pass in to be +distributed in the pulp. In growing teeth the pulp-cavity is widely open, +while in advanced age it often becomes obliterated, and the pulp itself +entirely converted into bone-like material. + +The _dentine_ or _ivory_ forms the principal constituent of the greater +number of teeth. When developed in its most characteristic form, it is +a very hard but elastic substance, white, with a yellowish tinge, and +slightly translucent. It consists of an organic matrix, something like, +but not identical with, that of bone, richly impregnated with calcareous +salts (chiefly calcium phosphate), these constituting in a fresh human +tooth 72 per cent of its weight. When subjected to microscopical +examination it is seen to be everywhere permeated by nearly parallel +branching tubes which run, in a slightly curving or wavy manner, in a +general direction from the centre towards the free surface of the tooth. +These tubes communicate by open mouths with the pulp-cavity, and usually +terminate near the periphery of the dentine by closed ends or loops, +though in Marsupials and certain other mammals they penetrate into the +enamel. They are occupied in the living tooth by soft gelatinous fibrils +connected with the cells of the pulp. A variety of dentine, permeated +by canals containing blood-vessels, met with commonly in fishes and +in some few mammals, as the _Megatherium_, is called vaso-dentine. +Other modifications of this tissue occasionally met with are called +osteodentine and secondary dentine,—the latter being a dentine of +irregular structure which often fills up the pulp-cavity of old animals. + +The _enamel_ constitutes a thin investing layer, complete or partial, of +the outer or exposed and working surface of the dentine of the crown of +the teeth of most mammals. This is the hardest tissue met with in the +animal body, containing from 95 to 97 per cent of mineral substances +(chiefly calcium phosphate and some carbonate, with traces of fluoride). +Its ultimate structure consists of prismatic fibres, placed generally +with their long axes at right angles to the free surface of the tooth. +Enamel is easily distinguished from dentine with the naked eye by its +clear, bluish-white, translucent appearance. + +The _cement_ or _crusta petrosa_ is always the most externally placed +of the hard tissues of which teeth are composed, as will be understood +when the mode of development of these organs is considered. It is often +only found as a thin layer upon the surface of the root; but sometimes, +as in the complex-crowned molar teeth of the Horse and Elephant, it is a +structure which plays a very important part, covering and filling in the +interstices between the folds of the enamel. In appearance, histological +structure, and chemical composition it is closely allied to osseous +tissue, containing lacunæ and canaliculi, though only when it is of +considerable thickness are Haversian canals present in it. + +_Development._—The two principal constituents of the teeth, the dentine +and the enamel, are developed from the two layers of the mucous membrane +of the jaw—the dentine from the deeper or vascular, the enamel from the +superficial or epithelial layer. The latter dips down into the substance +of the gum, and forms the enamel-organ or germ, the first rudiment of the +future tooth, which is constantly present even in those animals in which +the enamel is not found as a constituent of the perfectly-formed tooth. +Below the mass of epithelial cells thus embedded in the substance of the +gum, and remaining connected by a narrow neck of similar structure with +the epithelium of the surface, a portion of the vascular areolar tissue +becomes gradually separated and defined from that which surrounds it, +and assumes a distinct form, which is that of the crown of the future +tooth,—a single cone in the case of simple teeth, or with two or more +eminences in the complex forms. This is called the dental papilla or +dentine germ, and by the gradual conversion of its tissue into dentine +the bulk of the future tooth is formed, the uncalcified central portion +remaining as the pulp. The conversion of the papilla into hard tissue +commences at the outer surface of the apex, and gradually proceeds +downwards and inwards, so that the form of the papilla exactly determines +the form of the future dentine, and no alteration either in shape or +size of this portion of the tooth, when once calcified, can take place +by addition to its outer surface. In the meanwhile, calcification of a +portion of the cells of the enamel-organ, which adapts itself like a cap +round the top of the dentinal papilla, and has assumed a somewhat complex +structure, results in the formation of the enamel-coating of the crown of +the tooth. While these changes are taking place the tissues immediately +surrounding the tooth-germ become condensed and differentiated into a +capsule, which appears to grow up from the base of the dental papilla, +and encloses both this and the enamel-germ, constituting the follicle +or tooth-sac. By the ossification of the inner layer of this follicle +the cement is formed. This substance, therefore, unlike the dentine, +increases from within outwards, and its growth may accordingly be the +cause of considerable modification of form and enlargement, especially +of the roots, of certain teeth, as those of Seals and some Cetacea. The +delicate homogeneous layer coating the enamel surface of newly-formed +teeth, in which cement is not found in the adult state, and known as +Nasmyth’s membrane, is considered by Tomes as probably a film of this +substance, too thin to exhibit its characteristic structure, though +by others it is believed to be derived from the external layer of the +enamel-organ. The homology of the teeth with the dermal appendages, +hairs, scales, and claws, has already been alluded to, and it will now +be seen that in both cases two of the primary embryonic layers are +concerned in their development—the mesoblast and epiblast—although in +very different proportions respectively. Thus in the hair or nail the +part derived from the epiblast forms the principal bulk of the organ, the +mesoblast only constituting the papilla or matrix. But in the tooth the +epiblastic portion is limited to the enamel, and is always of relatively +small bulk and often absent, while the dentine (the principal constituent +of the tooth) and the cement are formed from the mesoblast. + +When more than one set of teeth occur in mammals, those of the second +set are developed in a precisely similar manner to the first, but the +enamel-germ, instead of being derived directly from an independent +part of the oral epithelium, is formed from a budding out of the neck +of the germ of the tooth succeeded. In the case of the true molars, +which have no predecessors, the germ of the first has an independent +origin, but that of the others is derived from the neck of the germ of +the tooth preceding it in the series. The foundations of the permanent +teeth are thus laid as it were almost simultaneously with those of their +predecessors, although they remain in many cases for years before they +are developed into functional activity. + +Although the commencement of their formation takes place at an early +period of embryonic life, teeth are in nearly all mammals still concealed +beneath the gum at the time of birth. The period of eruption, or +“cutting” of the teeth as it is called, that is, their piercing through +and rising above the surface of the mucous membrane, varies much in +different species. In some, as Seals, the whole series of teeth appears +almost simultaneously; but more often there are considerable intervals +between the appearance of the individual teeth, the front ones usually +coming into place first, and those at the back of the mouth at a later +period. + +_Forms of Teeth._—The simplest form of tooth may be exemplified on a +large scale by the tusk of the Elephant (Fig. 1, I.) It is a hard mass +almost entirely composed of dentine, of a conical shape at first, but +during growth becoming more and more cylindrical or uniform in width. +The enamel-covering, present on the apex in its earliest condition, soon +disappears, but a thin layer of cement covers the circumference of the +tooth throughout life. In section it will be seen that the basal portion +is hollow, and contains a large conical pulp, as broad at the base as the +tooth itself, and deeply imbedded in the bottom of a recess, or socket, +in the maxillary bone. This pulp continues to grow during the lifetime +of the animal, and at the same time is converted at its surface into +dentine. The tooth therefore continually elongates, but the use to which +the animal subjects it in its natural state causes the apex to wear away, +at a rate generally proportionate to the growth at the base, otherwise it +would become of inconvenient length and weight. Such teeth of indefinite +growth are said to be “rootless,” or to have “persistent pulps.” + +[Illustration: FIG. 1.—Diagrammatic Sections of various forms of Teeth. +I. Incisor or tusk of Elephant, with pulp-cavity persistently open +at base. II. Human incisor during development, with root imperfectly +formed, and pulp-cavity widely open at base. III. Completely formed human +incisor, with pulp-cavity contracted to a small aperture at the end of +the root. IV. Human molar, with broad crown and two roots. V. Molar +of the Ox, with the enamel covering the crown deeply folded, and the +depressions filled up with cement. The surface is worn by use; otherwise +the enamel coating would be continuous at the top of the ridges. In all +the figures the enamel is black, the pulp white, the dentine represented +by horizontal lines, and the cement by dots.] + +One of the corresponding front teeth of man (Fig. 2, II. and III.) may +be taken as an example of a very different condition. After its crown is +fully formed by calcification of the germ, the pulp, though continuing to +elongate, begins to contract in diameter; a neck or slight constriction +is formed; and the remainder of the pulp is converted into the root +(often, but incorrectly, called “fang”), a tapering conical process +imbedded in the alveolar cavity of the bone, and having at its extremity +a minute perforation, through which the vessels and nerves required to +maintain the vitality of the tooth enter the pulp-cavity, which is very +different from the widely open cavity at the base of the growing tooth. +When the crown of the tooth is broad and complex in character, instead of +having a single root, it may be supported by two or more roots, each of +which is implanted in a distinct alveolar recess or socket, and to the +apex of which a branch of the common pulp-cavity is continued (Fig. 1, +IV.) Such teeth are called “rooted teeth.” When they have once attained +their position in the jaw, with the neck a little way above the level +of the free margin of the alveolus, and embraced by the gum or tough +fibrovascular membrane covering the alveolar border, and having the root +fully formed, they can never increase in length or alter their position; +if they appear to do so in old age, it being only in consequence of +absorption and retrocession of the surrounding alveolar margins. If, +as often happens, their surface wears away in mastication, it is never +renewed. The open cavity at the base of the imperfectly developed tooth +(Fig. 1, II.) causes it to resemble the persistent condition of the +rootless tooth. The latter is therefore a more primitive condition, +the formation of the root being a completion of the process of tooth +development. Functionally it is, however, difficult to say that the one +is a higher form than the other, since they both serve important and +different purposes in the animal economy. + +As is almost always the case in nature, intermediate conditions between +these two forms of teeth are met with. Thus some teeth, as the molars of +the Horse, and of many Rodents, are for a time rootless, and have growing +pulps producing very long crowns with parallel sides, the summits of +which may be in use and beginning to wear away while the bases are still +growing; but ultimately the pulp contracts, forms a neck and distinct +roots, and ceases to grow. The canine tusks of the Musk Deer and of the +Walrus have persistent pulps, and are open at their base until the animal +is of advanced age, when they close, and the pulp ceases to be renewed. +The same sometimes happens in the tusks of very old Boars. + +The simplest form of the crown of a tooth is that of a cone; but this may +be variously modified. Thus it may be flattened, with its edges sharp +and cutting, and pointed at the apex, as in the laterally compressed +premolars of most Carnivora; or it may be chisel- or awl-shaped, with a +straight truncated edge, as in the human incisors; or it may be broad, +with a flat or rounded upper surface. Very often there is a more or less +prominent ridge encircling the whole or part of the base of the crown +just above the neck, called the cingulum, which serves as a protection to +the edge of the gum in masticating, and is most developed in flesh-eating +and insectivorous animals, in which the gums are liable to be injured by +splinters of bone or other hard fragments of their food. The form of the +crown is frequently rendered complex by the development upon its surface +of elevations or tubercules called cusps or cones, or by ridges usually +transverse, but sometimes variously curved or folded. When the crown +is broad and the ridges are greatly developed, as in the molars of the +Elephant, Horse, and Ox (Fig. 1, V.), the interspaces between them are +filled with cement, which supports them and makes a solid compact mass of +the whole tooth. When such a tooth wears away at the surface by friction +against the opposed tooth of the other jaw, the different density of +the layers of the substances of which it is composed—enamel, dentine, +and cement—arranged in characteristic patterns, causes them to wear +unequally, the hard enamel ridges projecting beyond the others, and thus +giving rise to a grinding surface of great mechanical advantage. + +_Succession._—The dentition of all mammals consists of a definite set +of teeth, almost always of constant and determinate number, form, +and situation, and, with few exceptions, persisting in a functional +condition throughout the natural term of the animal’s life. In many +species these are the only teeth which the animal ever possesses,—the +set which is first formed being permanent, or, if accidentally lost, +or decaying in extreme old age, not being replaced by others. These +animals are called Monophyodont. But in the larger number of mammals, +certain of the teeth are preceded by others, which may be only of a +very transient, rudimentary, and functionless character (being in the +Seals, for example, shed either before or within a few days after +birth), or may be considerably developed, and functionally occupy the +place of the permanent teeth for a somewhat lengthened period, during +the growth and development of the latter and of the jaws. In all cases +these teeth disappear (by the absorption of their roots and shedding +of the crowns) before the frame of the animal has acquired complete +maturity, as evidenced by the coalescence of the epiphyses of the +osseous system. As these teeth are, as a general rule, present during +the period in which the animal is nourished by the milk of the mother, +the name of “milk-teeth” (French _dents de lait_, German _milchzähne_) +has been commonly accorded to them, although it must be understood that +the epoch of their presence is by no means necessarily synchronous with +that of lactation. Animals possessing such teeth are called Diphyodont. +No mammal is known to have more than two sets of teeth; and the definite +and orderly replacement of certain members of the series is a process +of quite a different nature from the indefinite succession which takes +place in all the teeth continuously throughout the lifetime of the lower +vertebrates. + +When the milk-teeth are well developed, and continue in place during the +greater part of the animal’s growth, as is especially the case with the +Ungulata, and, though to a less degree, with the Primates and Carnivora, +their use is obvious, since taken all together they form structurally +a complete epitome on a small scale of the more numerous and larger +permanent set (see Fig. 3), and, consequently, are able to perform the +same functions, while time is allowed for the gradual maturation of +the latter, and especially while the jaws of the growing animal are +acquiring the size and strength sufficient to support the permanent +teeth. Those animals, therefore, that have a well-developed and tolerably +persistent set of milk-teeth may be considered to be in a higher state +of development, as regards their dentition, than those that have the +milk-teeth absent or rudimentary. + +It is a very general rule that individual teeth of the milk and permanent +set have a close relationship to one another, being originally formed, as +mentioned above, in exceedingly near proximity, and with, at all events +so far as the enamel-germ is concerned, a direct connection. Moreover, +since the latter ultimately come to occupy the position in the alveolar +border temporarily held by the former, they are spoken of respectively as +the predecessors or successors of each other. But it must be understood +that milk-teeth may be present which have no successors in the permanent +series, and, what is far more general, permanent teeth may have no +predecessors in the milk series. + +The complete series of permanent teeth of most mammals forms a complex +machine, with its several parts adapted for different functions,—the +most obvious structural modification for this purpose being an increased +complexity of the individual components of the series from the anterior +towards the posterior extremity of such series. Since, as has just been +said, the complete series of the milk teeth often presents structurally +and functionally a similar machine, but composed of fewer individual +members, and the anterior of which are as simple, and the posterior as +complex as those occupying corresponding positions in the permanent +series,—and since the milk-teeth are only developed in relation to +the anterior or lateral, never to the most posterior of the permanent +series,—it follows that the hinder milk-teeth are usually more complex +than the teeth of which they are the predecessors in the permanent +series, and represent functionally, not their immediate successors, but +those more posterior permanent teeth which have no direct predecessors. +This character is clearly seen in those animals in which the various +members of the molar series are well differentiated from each other in +form, as the Carnivora, and also in Man. + +In animals which have two sets of teeth the number of those of the +permanent series which are preceded by milk-teeth varies greatly, being +sometimes, as in Marsupials and some Rodents, as few as one on each side +of each jaw, and sometimes including the larger portion of the series. + +Although there are difficulties in some cases in arriving at a +satisfactory solution of the question, it is, on the whole, safest to +assume that when only one set of teeth is present, this corresponds to +the permanent teeth of the Diphyodonts. When this one set is completely +developed, and remains in use throughout the animal’s life, there can +be no question on this subject. When, on the other hand, the teeth are +rudimentary and transient, as in the Whalebone Whales, it is possible +to consider them as representing the milk series; but there are weighty +reasons in favour of the opposite conclusion.[5] + +_Arrangement, Homologies, and Notation of Teeth._—The teeth of the two +sides of the jaws are always alike in number and character, except in +cases of accidental or abnormal variation, and in the one remarkable +instance of constant deviation from bilateral symmetry among mammals, +the tusks of the Narwhal (_Monodon_), in which the left is of immense +size, and the right rudimentary. In certain mammals, such as the Dolphins +and some Armadillos, which have a very large series of similar teeth, +not always constant in number in different individuals, there may be +differences in the two sides; but, apart from these, in describing the +dentition of any mammal, it is quite sufficient to give the number and +characters of the teeth of one side only. Since the teeth of the upper +and the lower jaws work against each other in masticating, there is a +general correspondence or harmony between them, the projections of one +series, when the mouth is closed, fitting into corresponding depressions +of the other. There is also a general resemblance in the number, +characters, and mode of succession of both series, so that, although +individual teeth of the upper and lower jaws may not be in any strict +sense of the term homologous parts, there is a great convenience in +applying the same descriptive terms to the one as are used for the other. + +[Illustration: FIG. 2.—Upper and Lower Teeth of one side of the Mouth +of a Dolphin (_Lagenorhynchus_) as an example of the homodont type of +dentition. The bone covering the outer side of the roots of the teeth has +been removed to show their simple character.] + +The simplest dentition as a whole is that of many species of Dolphin +(Fig. 2), in which the crowns are single-pointed, slightly curved cones, +and the roots also single and tapering, and all alike in form from the +anterior to the posterior end of the series, though it may be with +some slight difference in size, those at the two extremities of the +series being rather smaller than the others. Such a dentition is called +Homodont, and in the case cited, as the teeth are never changed, it is +also Monophyodont. Such teeth are adapted only for catching slippery +living prey, as fish. + +In a very large number of mammals the teeth of different parts of the +series are more or less differentiated in character, and have different +functions to perform. The front teeth are simple and one-rooted, and +are adapted for cutting and seizing. They are called “incisors.” The +back- or cheek-teeth have broader and more complex crowns, tuberculated +or ridged, and are supported on two or more roots. They crush or grind +the food, and are hence called “molars.” Many animals have, between +these two sets, a tooth at each corner of the mouth, longer and more +pointed than the others, adapted for tearing or stabbing, or for fixing +struggling prey. From the conspicuous development of such teeth in the +Carnivora, especially the Dogs, they have received the name of “canines.” +A dentition with its component parts so differently formed that these +distinctive terms are applicable to them is called Heterodont. In most +cases, though by no means invariably, animals with Heterodont dentition +are also Diphyodont. + +This general arrangement is extremely obvious in a considerable number of +mammals; and closer examination shows that, under very great modification +in detail, there is a remarkable uniformity of essential characters in +the dentition of a large number of members of the class belonging to +different orders and not otherwise closely allied; so much so indeed that +it has been possible (chiefly through the researches of Sir Richard Owen) +to formulate a common plan of dentition from which the others have been +derived by the alteration of some and suppression of other members of the +series, and occasionally, but very rarely, by addition. The records of +palæontology fully confirm this view, as by tracing back many groups now +widely separated in dental characters we find a gradual approximation to +a common type. In this generalised form of mammalian dentition (which is +best exemplified in the genera _Anoplotherium_ and _Homalodontotherium_) +the entire number of teeth present is 44, or 11 above and 11 below on +each side. Those of each jaw are placed in continuous series without +intervals between them; and, although the anterior teeth are simple and +single-rooted, and the posterior teeth complex and with several roots, +the transition between the two kinds is gradual. + +In dividing and grouping such teeth for the purpose of description and +comparison, more definite characters are required than those derived +merely from form or function. The first step towards a classification +has been made by the observation that the upper jaw is composed of two +bones, the premaxilla and the maxilla, and that the suture between these +bones separates the three anterior teeth from the others. These three +teeth, then, which are implanted by their roots in the premaxilla, +form a distinct group, to which the name of “incisor” is applied. This +distinction is, however, not so important as it appears at first sight, +for, as mentioned when speaking of the development of the teeth, their +connection with the bone is only of a secondary nature, and, although it +happens conveniently for our purpose that in the great majority of cases +the segmentation of the bone coincides with the interspace between the +third and fourth tooth of the series, still, when it does not happen to +do so, as in the case of the Mole, we must not give too much weight to +this fact, if it contravenes other reasons for determining the homologies +of the teeth. The eight remaining teeth of the upper jaw offer a natural +division, inasmuch as the posterior three never have milk-predecessors; +and, although some of the anterior teeth may be in the same case, the +particular one preceding these three always has such a predecessor. These +three then are grouped apart as the “molars,” or, since some of the teeth +in front of them often have a molariform character, “true molars.” Of the +five teeth between the incisors and molars the most anterior, or that +which is usually situated close behind the premaxillary suture, almost +always, as soon as any departure takes place from the simplest and most +homogeneous type, assumes a lengthened and pointed form, and is the tooth +so developed as to constitute the “canine” or “laniary” tooth of the +Carnivora, the tusk of the Boar, etc. It is customary therefore to call +this tooth, whatever its size or form, the “canine.” The remaining four +are the “premolars” or “false molars.” This system of nomenclature has +been objected to as being artificial, and in many cases not descriptive, +the distinction between premolars and canine especially being sometimes +not obvious; but the terms are now in such general use, and are so +practically convenient—especially if, as it is best to do in all such +cases, we forget their original signification and treat them as arbitrary +signs—that it is not likely they will be superseded by any that have been +proposed as substitutes for them. + +With regard to the lower teeth the difficulties are greater, owing to the +absence of any suture corresponding to that which defines the incisors +above; but since the number of the teeth is the same, the corresponding +teeth are preceded by milk-teeth, and in the large majority of cases it +is the fourth tooth of the series which is modified in the same way as +the canine (or fourth tooth) of the upper jaw, it is quite reasonable +to adopt the same divisions as with the upper series, and to call the +first three, which are implanted in the part of the mandible opposite +to the premaxilla, the incisors, the next the canine, the next four the +premolars, and the last three the molars. It may be observed that when +the mouth is closed, especially when the opposed surfaces of the teeth +present an irregular outline, the corresponding upper and lower teeth +are not exactly opposite, otherwise the two series could not fit into +one another; but as a rule the points of the lower teeth shut into the +interspaces in front of the corresponding teeth of the upper jaw. This +is seen very distinctly in the canine teeth of the Carnivora, and is a +useful guide in determining the homologies of the teeth of the two jaws. +Objections have certainly been made to this view, because, in certain +rare cases, the tooth which, according to it, would be called the lower +canine has the form and function of an incisor (as in Ruminants and +Lemurs), and on the other hand (as in _Cotylops_, an extinct Ungulate +from North America) the tooth that would thus be determined as the +first premolar has the form of a canine; but it should not be forgotten +that, as in all such cases, definitions derived from form and function +alone are quite as open to objection as those derived from position and +relation to surrounding parts, or still more so. + +_Dental formulæ._—For the sake of brevity the complete dentition, +arranged according to these principles, is often described by the +following formula, the numbers above the line representing the teeth of +the upper, those below the line those of the lower jaw:—incisors ³⁻³⁄₃₋₃, +canines ¹⁻¹⁄₁₋₁, premolars ⁴⁻⁴⁄₄₋₄, molars ³⁻³⁄₃₋₃ = ¹¹⁻¹¹⁄₁₁₋₁₁; total +44. Since, however, initial letters may be substituted for the names of +each group, and it is quite unnecessary to give more than the numbers +of the teeth on one side of the mouth, the formula may be conveniently +abbreviated into— + + _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃ = ¹¹⁄₁₁; total 44. + +The individual teeth of each group are always enumerated from before +backwards, and by such a formula as the following— + + _i_ 1, _i_ 2, _i_ 3, _c_, _p_ 1, _p_ 2, _p_ 3, _p_ 4, _m_ 1, _m_ 2, _m_ 3 + ------------------------------------------------------------------------- + _i_ 1, _i_ 2, _i_ 3, _c_, _p_ 1, _p_ 2, _p_ 3, _p_ 4, _m_ 1, _m_ 2, _m_ 3 + +or more briefly— + + 1,2,3 1 1,2,3,4 1,2,3 + _i_ ------ _c_ -- _p_ -------- _m_ -----. + 1,2,3, 1, 1,2,3,4, 1,2,3 + +A special numerical designation is thus given by which each one can be +indicated. In mentioning any single tooth, such a sign as _m¹_⁄ will mean +the first upper molar, ⁄_m₁_ the first lower molar, and so on. The use of +such signs saves much time and space in description.[6] + +It was part of the view of the founder of this system of dental notation +that, at least throughout the group of mammals whose dentition is +derived from this general type, each tooth has its strict homologue in +all species, and that in those cases in which fewer than the typical +number are present (as in all existing mammals except the genera _Sus_, +_Gymnura_, _Talpa_, and _Myogale_), the teeth that are missing can be +accurately defined. According to this view, when the number of incisors +falls short of three it is assumed that the absent ones are missing +from the outer and posterior end of the series. Thus, when there is +but one incisor present, it is _i_ 1; when two, they are _i_ 1 and +_i_ 2. Furthermore, when the premolars and the molars are below their +typical number, the absent teeth are missing from the fore part of the +premolar series, and from the back part of the molar series. If this were +invariably so, the labours of those who describe teeth would be greatly +simplified; but there are so many exceptions that a close scrutiny into +the situation, relations, and development of a tooth is required before +its nature can be determined, and in some cases the evidence at our +disposal is scarcely sufficient for the purpose. In other instances, +however, as among the Polyprotodont Marsupials, we have decisive evidence +to show that the missing premolar teeth are not those at the extremity of +the series. + +[Illustration: FIG. 3.—Milk and Permanent Dentition of Upper (I.) and +Lower (II.) Jaw of the Dog (_Canis familiaris_), with the symbols by +which the different teeth are commonly designated. The third upper molar +(_m._3) is the only tooth wanting in this animal to complete the typical +heterodont mammalian dentition.] + +The milk-dentition is expressed by a similar formula, _d_ for deciduous +or _m_ for milk being commonly prefixed to the letter expressive of +the nature of the tooth. Since the three molars, and almost invariably +the first premolar of the permanent series, have no predecessors, the +typical milk-dentition would be expressed as follows—_di_ ³⁄₃, _dc_ +¹⁄₁, _dm_ ³⁄₃, = ⁷⁄₇, total 28. In a few Ungulates, however, such as +the Hyrax and Tapir, and in some instances the Rhinoceros and the +extinct _Palæotherium_, the whole of the four premolars are preceded +by milk-teeth; when we have the fullest development of cheek-teeth in +the whole of the Eutheria. The teeth which precede the premolars of the +permanent series are all called molars in the milk-dentition, although +as a general rule, in form and function they represent in a condensed +form the whole premolar and molar series of the adult. When there is +a marked difference between the premolars and molars of the permanent +dentition, the first milk-molar resembles a premolar, while the last has +the characters of the posterior true molar. + +The dentition of all the members of the orders Primates, Carnivora, +Insectivora, Chiroptera, and Ungulata can clearly be derived from the +above-described generalised type. The same may be said of the Rodents, +and even the Proboscidea, though at least in the existing members of the +order with greater modification. It is also apparent in certain extinct +Cetacea, as _Zeuglodon_ and _Squalodon_, but it is difficult to find +any traces of it in existing Cetacea, Sirenia, or any of the so-called +Edentata. All the Marsupials, different as they are in their general +structure and mode of life, and variously modified as is their dentition, +present in this system of organs some deep-lying common characters +which show their unity of origin. The generalised type to which their +dentition can be reduced presents considerable resemblance to that of the +placental mammals, yet differing in details. It is markedly heterodont, +and susceptible of division into incisors, canines, premolars, and molars +upon the same principles. The whole number is, however, not limited to +forty-four. The incisors may be as numerous as five on each side above, +and they are almost always different in number in the upper and the lower +jaw. The premolars and molars are commonly seven, as in the placental +mammals, but their arrangement is reversed, as there are four true molars +and three premolars. + +The larger number of incisive and molar teeth among the Marsupials +suggests that their additional teeth have disappeared in the Eutheria,[7] +and Mr. O. Thomas has endeavoured to construct a generalised dental +formula from which both the Marsupial and Eutherian modifications +may have been derived by the suppression of particular teeth. Thus +the hypothetical formula _i_ ¹,²,³,⁴,⁵⁄₁,₂,₃,₄,₅, _c_ ¹⁄₁, _p_ +¹,²,³,⁴⁄₁,₂,₃,₄, _m_ ¹,²,³,⁴,⁵⁄₁,₂,₃,₄,₅, by the loss of the fifth +lower incisor, and of the second premolars (which we know to be those +which disappear in the Marsupials) and the fifth molars, will give _i_ +¹,²,³,⁴,⁵⁄₁,₂,₃,₄,₀, _c_ ¹⁄₁, _p_ ¹,⁰,³,⁴⁄₁,₀,₃,₄, _m_ ¹,²,³,⁴⁄₁,₂,₃,₄; +or the formula of the Opossum (_Didelphys_), usually written _i_ ⁵⁄₄, _c_ +¹⁄₁, _p_ ³⁄₃, _m_ ⁴⁄₄. Again, in the same formula the loss of the fourth +and fifth incisors in both jaws, and also of the fourth molars, gives us +_i_ ¹,²,³,⁰,⁰⁄₁,₂,₃,₀,₀, _c_ ¹⁄₁, _p_ ¹,²,³,⁴⁄₁,₂,₃,₄, _m_ ¹,²,³⁄₁,₂,₃, +or the formula of a typical Eutherian, like the Pig, which we generally +write as _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃. Such a generalised formula +will admit of modification into that of all existing, and a large number +of fossil Marsupials, but it is possible that some of the Mesozoic types +may have had more than four premolars, although there is no absolutely +decisive evidence that such was the case. The presence of seven or eight +true molars in some Mesozoic forms merely entails the addition of two or +three additional figures to the ideal generalised formula. + +The milk-dentition of all known Marsupials, existing or extinct, is (if +not entirely absent) limited to a single tooth on either side of each +jaw, this being the predecessor of the last permanent premolar. And if +the view that the milk-dentition is an additional series grafted upon the +original permanent series be correct, it is evident that we have in this +single replacement the first stage of this additional development. + +In very few mammals are teeth entirely absent. Even in the Whalebone +Whales their germs are formed in the same manner and at the same period +of life as in other mammals, and even become partially calcified, but +they never rise above the gums, and completely disappear before the birth +of the animal. In some species of the order Edentata, the true Anteaters +and the Pangolins, no traces of teeth have been found at any age. The +adult Monotremata are likewise devoid of teeth of the same structure +as those of ordinary mammals; but well-developed molars occur in the +young _Ornithorhynchus_, although no traces of teeth have hitherto been +detected in _Echidna_. + +_Modifications of the Teeth in Relation to their Functions._—The +principal functional modifications noticed in the dentition of mammalia +may be roughly grouped as piscivorous, carnivorous, insectivorous, +omnivorous, and herbivorous, each having, of course, numerous variations +and transitional conditions. + +The essential characters of a piscivorous dentition are best exemplified +in the Dolphins, and also (as modifications of the carnivorous type) in +the Seals. This type consists of an elongated, rather narrow mouth, wide +gape, with numerous subequal, conical, sharp-pointed, recurved teeth, +adapted simply to rapidly seize, but not to divide or masticate, active, +slippery, but not powerful prey. All animals which feed on fish as a +rule swallow and digest them entire, a process which the structure of +prey of this nature, especially the intimate interblending of delicate, +sharp-pointed bones with the muscles, renders very advantageous, and for +which the above-described type of dentition is best adapted. + +The carnivorous type of dentition is shown in its most specialised +development among existing mammals in the _Felidæ_. The function being +here to seize and kill struggling animals, often of large size and great +muscular power, the canines are immensely developed, trenchant, and +piercing, and are situated wide apart, so as to give the firmest hold +when fixed in the victim’s body. The jaws are as short as is consistent +with the free action of the canines, so that no power may be lost. The +incisors are very small, so as not to interfere with the penetrating +action of the canines, and the crowns of the molar series are reduced +to scissor-like blades, with which to pare off the soft tissues from +the large bones, or to divide into small pieces the less dense portions +of the bones for the sake of nutriment afforded by the blood and marrow +they contain. The gradual modification between this and the two following +types will be noticed in their appropriate places. + +In the most typical insectivorous animals, as the Hedgehogs and Shrews, +the central incisors are elongated, pointed, and project forwards, those +of the upper and lower jaw meeting like the blades of a pair of forceps, +so as readily to secure small active prey, quick to elude capture, but +powerless to resist when once seized. The crowns of the molars are +covered with numerous sharp edges and points, which, working against each +other, rapidly cut up the hard-cased insects into little pieces fit for +swallowing and digestion. + +The omnivorous type, especially that adapted for the consumption of soft +vegetable substances, such as fruits of various kinds, may be exemplified +in the dentition of Man, of most Monkeys, and of the less modified Pigs. +The incisors are moderate, subequal, and cutting. If the canines are +enlarged, it is usually for other purposes than those connected with +food, and only in the male sex. The molars have their crowns broad, +flattened, and elevated into rounded tubercles. The name _Bunodont_, or +hillock-toothed, has been proposed for molars of this type, and will +frequently be found convenient. + +In the most typically herbivorous forms of dentition, as seen in the +Horse and Kangaroo, the incisors are well developed, trenchant, and +adapted for cutting off the herbage on which the animals feed; the +canines are rudimentary or suppressed; the molars are large, with broad +crowns, which in the simplest forms have strong transverse ridges, but +may become variously complicated in the higher degrees of modification +which this type of tooth assumes. + +Various forms of teeth of this type will be noticed among the Ungulates +and Rodents. + +The natural groups of mammals, or those which in our present state of +knowledge we have reason to believe are truly related to each other, may +each contain examples of more than one of these modifications. Thus the +Primates have both omnivorous and insectivorous forms. The Carnivora show +piscivorous, carnivorous, insectivorous, and omnivorous modifications of +their common type of dentition. The Ungulata and the Rodentia have among +them the omnivorous and various modifications, both simple and complex, +of the herbivorous type. The Marsupialia exhibit examples of all forms, +except the purely piscivorous. Other orders, more restricted in number or +in habits, as the Proboscidea and Cetacea, naturally do not show so great +a variety in the dental structure of their members. + +_Taxonomy._—In considering the taxonomic value to be assigned to the +modifications of teeth of mammals, two principles, often opposed to each +other, which have been at work in producing these modifications, must +be held in view:—(1) the type, or ancestral form, as we generally now +call it, characteristic of each group, which in most mammals is itself +derived from the still more generalised type described above; and (2) +variations which have taken place from this type, generally in accordance +with special functions which the teeth are called upon to fulfil in +particular cases. These variations are sometimes so great as completely +to mask the primitive type, and in this way the dentition of many animals +of widely different origin has come to present a remarkable superficial +resemblance, as in the case of the Wombat (a Marsupial), the Aye-Aye (a +Lemur), and the Rodents, or as in the case of the Thylacine and the Dog. +In all these examples indications may generally be found of the true +nature of the case by examining the earlier conditions of dentition; +for the characters of the milk-teeth or the presence of rudimentary +or deciduous members of the permanent set will generally indicate the +route by which the specialised dentition of the adult has been derived. +It is perhaps owing to the importance of the dental armature to the +well-being of the animal in procuring its sustenance, and preserving +its life from the attacks of enemies, that great changes appear to have +taken place so readily, and with such comparative rapidity, in the forms +of these organs—changes often accompanied with but little modification +in the general structure of the animal. Of this proposition the Aye-Aye +(_Chiromys_) among Lemurs, the Walrus among Seals, and the Narwhal +among Dolphins form striking examples; since in all these forms the +superficial characters of their dentition would entirely separate them +from the animals with which all other evidence (even including the mode +of development of their teeth) proves their close affinity. + +[Illustration: FIG. 4.—Molar teeth of Mesozoic Mammals (enlarged). +Triconodont type—1, _Dromatherium_; 2, _Microconodon_; 3, +_Amphilestes_; 4, _Phascolotherium_; 5, _Triconodon_. Tritubercular +type—6, 7, _Spalacotherium_; 10, _Asthenodon_. Tubercular sectorial +type—8, _Amphitherium_; 9, _Peramus_; 11-13, _Amblotherium_; 14 (?) +_Amblotherium_. _pr_, Protocone; _hy_, hypocone; _pa_, paracone; _me_, +metacone, in the upper teeth; and protoconid, hypoconid, paraconid, and +metaconid in the lower. 6 and 15 are upper molars, and the rest lower +molars. (After Osborn.)] + +_Trituberculism._—Recent researches, and more especially those of +Professors Cope and Osborn, tend to show that almost all of the extremely +different forms of tooth-structure found among Mammals may be traced to +one common type, in which the crown of each tooth carried three cusps, +and hence termed the _tritubercular_ type; these three cusps being +arranged in a triangle, with the apex directed inwardly in the upper +teeth (Fig. 4, ₆), and outwardly in the lower ones (Fig. 4, ₇). It is +further probable that this tritubercular type was itself derived from +a type of dentition in which the teeth were in the form of almost a +quite simple cone; such a presumably primitive type of dentition—being +apparently retained among some existing Edentates, like the Armadillos, +while it is possible that we should regard the dentition of the existing +Cetacea (Fig. 2) as a reversion to the same primitive type. None of +the Mesozoic mammals at present known exhibit this simple conical type +of teeth, although we have an approximation to it in the extremely +generalised genus _Dromatherium_. Starting then from this presumed simple +cone it appears that the teeth of _Dromatherium_ (Fig. 4, ₁) present the +first stage towards trituberculism, the crown of each tooth having one +main cone, with minute lateral cusps, and the root being grooved. In +the next or true Triconodont stage (Fig. 4, ₃₋₅) the crown has become +elongated antero-posteriorly, and consists of one central and two lateral +cones or cusps, while the root is divided. From this the transition is +easy to the tritubercular type, in which the three cusps, instead of +being placed in a line, are arranged in a triangle; the upper teeth +(Fig. 4, ₆) having one inner and two outer cusps, while the reverse +condition obtains in those of the lower jaw (Fig. 4, ₇). These three +cusps of the simple tritubercular tooth are collectively designated as +the primitive triangle; in the upper tooth the inner cusp is termed the +protocone, the antero-external one the paracone, and the postero-external +the metacone; the corresponding cusps of the lower tooth being named +protoconid, paraconid, and metaconid—the protoconid being here on the +outer side of the crown. + +It is thus apparent that in the first, or haplodont type, as well as in +the triconodont type, the upper and lower molars are alike; while in +the simple tritubercular type they have a similar pattern, but with the +arrangement of the cusps reversed. This simple tritubercular type occurs +in the Mesozoic genus _Spalacotherium_ (Fig. 4, ₆ and ₇), and apparently +in the existing _Chrysochloris_; but in the majority of tritubercular +forms, while this primitive triangle forms the main portion of the +crown, other secondary cusps are added, the homologies of which in the +upper and lower teeth are somewhat doubtful. At the same time that we +have the addition of these secondary cusps we also find trituberculism +differentiating into a secodont and a bunodont series, according as to +whether the dentition becomes of a cutting or a crushing type. + +Thus in the lower molars (Fig. 4, ₈ and ₉) we very frequently find the +three cusps of the primitive triangle elevated and connected by cross +crests, while there is an additional low posterior heel or talon, which +may be termed the hypoconid. This tubercular-sectorial sub-type, as it +is termed, is found in the lower molars of many Polyprotodont Marsupials +and Insectivores, and it also occurs in the lower carnassial teeth of the +true Carnivora. The presence of two cusps (inner and outer) to the talon +converts this modification into a quinquetubercular form; while, by the +suppression of one of the three primitive cusps, it develops into the +quadritubercular type of the bunodont series. + +[Illustration: FIG. 5.—Diagram of two upper and two lower left +quadritubercular molars in mutual apposition. The cusps and ridges +of the upper molars in double lines, and those of the lower in black +lines. The lower molars are looked at from below, as if transparent. +_pr_, Protocone; _hy_, hypocone; _pa_, paracone; _me_, metacone; _ml_, +protoconule; _pl_, metaconule; _prd_, protoconid; _hyd_, hypoconid; +_pad_, paraconid; _med_, metaconid; _end_, entoconid. (After Osborn.)] + +In the upper molars the primitive triangle in the secodont series may +remain purely tricuspid; but the addition of intermediate cusps, both in +the secodont and bunodont series, may give rise to a quinquetubercular +type; these intermediate cusps being respectively designated as the +protoconule and metaconule (Fig. 5, _ml_, _pl_). Finally, in the +bunodont series, the addition of a postero-internal cusp (Fig. 5, _hy_), +termed the hypocone, forms the sextubercular molar. + +The following table exhibits, in a collective form, the names and +relations of all the above-mentioned cusps, and the letters by which they +are indicated in the figures:— + + UPPER MOLARS. + + Antero-internal cusp = protocone = _pr_. + Postero ” or 6th cusp = hypocone = _hy_. + Antero-external cusp = paracone = _pa_. + Postero ” ” = metacone = _me_. + Anterior intermediate cusp = protoconule = _ml_. + Posterior ” ” = metaconule = _pl_. + + LOWER MOLARS. + + Antero-external cusp = protoconid = _prd_. + Postero ” ” = hypoconid = _hyd_. + Antero-internal or 5th cusp = paraconid = _pad_. + Intermediate (or in quadritubercular + molars antero-internal) cusp = metaconid = _med_. + Postero-internal cusp = entaconid = _end_. + +The common occurrence of trituberculism in the mammals of the earlier +geological epochs is, as remarked by Osborn, very significant of the +uniformity of molar origin. Thus, among the Mesozoic mammals (with the +exception of the group known as Multituberculata, in which the molars +are constructed on a different type), trituberculism occurs in the +great majority of the genera; while out of 82 species, belonging to +five different suborders from the Lowest or Puerco Eocene of the United +States, all but four exhibit this feature; and the same holds good for +the mammals of the corresponding European horizon. At the present day +trituberculism persists in the Lemuroidea, Insectivora, Carnivora, and +Marsupialia. In the Carnivora there is a tendency to lose the metaconid, +while in the bunodont molars of the Ungulata it is the paraconid that +disappears. + + +III. THE SKELETON. + +_Definition._—The skeleton is a system of hard parts, forming a +framework which supports and protects the softer organs and tissues +of the body. It consists of dense fibrous and cartilaginous tissues, +portions of which remain through life in this state, but the greater +part is transformed during the growth of the animal into bone or osseous +tissue. This is characterised by a peculiar histological structure and +chemical composition, being formed mainly of a gelatinous basis, strongly +impregnated with salts of calcium, chiefly phosphate, and disposed in a +definite manner, containing numerous minute nucleated spaces or cavities +called lacunæ, connected together by delicate channels or canaliculi, +which radiate in all directions from the sides of the lacunæ. Parts +composed of bone are, next to the teeth, the most imperishable of all +the organs of the body, often retaining their exact form and internal +structure for ages after every trace of all other portions of the +organisation has completely disappeared, and thus, in the case of extinct +animals, affording the only means of attaining a knowledge of their +characters and affinities.[8] + +In the Armadillos and their extinct allies alone is there an ossified +exoskeleton, or bony covering developed in the skin. In all other mammals +the skeleton is completely internal. It may be described as consisting +of an axial portion belonging to the head and trunk, and an appendicular +portion belonging to the limbs. There are also certain bones called +splanchnic, being developed within the substance of some of the viscera. +Such are the _os cordis_ and _os penis_ found in some mammals. + +It is characteristic of all the larger bones of the mammalia that their +ossification takes its origin from several distinct centres. One near +the middle of the bone, and spreading throughout its greater portion, +constitutes the _diaphysis_, or “shaft,” in the case of the long +bones. Others near the extremities, or in projecting parts, form the +_epiphyses_, which remain distinct during growth, but ultimately coalesce +with the rest of the bone. + +_Axial skeleton._—The axial skeleton consists of the skull, the vertebral +column (prolonged at the posterior extremity into the tail), the sternum, +and the ribs. + +_Skull._—In the _skull_ of adult mammals, all the bones, except the +lower jaw, the auditory ossicles, and the bones of the hyoid arch, are +immovably articulated together, their edges being in close contact, +and often interlocking by means of fine denticulations projecting from +one bone and fitting into corresponding depressions of the other; +they are also held together by the investing periosteum, or fibrous +membrane, which passes directly from one to the other, and permits +no motion, beyond perhaps a slight yielding to external pressure. +In old animals there is a great tendency for the different bones to +become actually united by the extension of ossification from one to +the other, with consequent obliteration of the sutures. The cranium, +thus formed of numerous originally independent ossifications, which may +retain throughout life more or less of their individuality, or be all +fused together, according to the species, the age, or even individual +peculiarity, consists of a brain-case, or bony capsule for enclosing and +protecting the brain, and a face for the support of the organs of sight, +smell, and taste, and of those concerned in seizing and masticating the +food. The brain-case articulates directly with the anterior cervical +vertebra, by means of a pair of oval eminences, called condyles, placed +on each side of the large median foramen which transmits the spinal cord. +It consists of a basal axis, continuous serially with the axes or centra +of the vertebræ, and of an arch above, roofing over and enclosing the +cavity which contains the cephalic portion of the central nervous system +(see Fig. 6). The base with its arch is composed of three segments placed +one before the other, each of which is comparable to a vertebra with a +greatly expanded neural arch. The hinder or occipital segment consists +of the basioccipital, exoccipital, and supraoccipital bones; the middle +segment of the basisphenoid, alisphenoid, and parietal bones; and the +anterior segment of the presphenoid, orbitosphenoid, and frontal bones. +The axis is continued forwards into the mesethmoid, or septum of the +nose, around which the bones of the face are arranged in a manner so +extremely modified for their special purposes that anatomists who have +attempted to trace their serial homologies with the more simple portions +of the axial skeleton have arrived at very diverse interpretations. +The characteristic form and structure of the face of mammals is mainly +dependent upon the size and shape of (1) the orbits, a pair of cup-shaped +cavities for containing the eyeball and its muscles, which may be +directed forwards or laterally, placed near together or wide apart, and +may be completely or only partially encircled by bone; (2) the nasal +fossæ, or cavities on each side of the median nasal septum, forming the +passage for the air to pass between the external and the internal nares, +and containing in their upper part the organ of smell; (3) the zygomatic +arch, a bridge of bone for the purpose of muscular attachment, which +extends from the side of the face to the skull, overarching the temporal +fossa; (4) the roof of the mouth, with its alveolar margin for the +implantation of the upper teeth. The face is completed by the mandible, +or lower jaw, consisting of two lateral rami, articulated by a hinge +joint with the squamosal (a cranial bone interposed between the posterior +and penultimate segment of the brain-case, where also the bony capsule of +the organ of hearing is placed), each being composed of a single solid +piece of bone, and the two united together in the middle line in front, +at the symphysis,—which union may be permanently ligamentous or become +completely ossified. Into the upper border of the mandibular rami the +lower teeth are implanted. + +[Illustration: FIG. 6.—Longitudinal and vertical section of the skull of +a Dog (_Canis familiaris_), with mandible and hyoid arch. _an_, Anterior +narial aperture; _MT_, maxillo-turbinal bone; _ET_, ethmo-turbinal; +_Na_, nasal; _ME_, ossified portion of the mesethmoid; _CE_, cribriform +plate of the ethmo-turbinal; _Fr_, frontal; _Pa_, parietal; _IP_, +interparietal; _SO_, supraoccipital; _ExO_, exoccipital; _BO_, +basioccipital; _Per_, periotic; _BS_, basisphenoid; _Pt_, pterygoid; +_AS_, alisphenoid; _OS_, orbitosphenoid; _PS_, presphenoid; _PI_, +palatine; _VO_, vomer; _Mx_, maxilla; _PMx_, premaxilla; _sh_, stylohyal; +_eh_, epihyal; _ch_, ceratohyal; _bh_, basihyal; _th_, thyrohyal; _s_, +symphysis of mandible; _cp_, coronoid process; _cd_, condyle; _a_, angle; +_id_, inferior dental canal. The mandible is displaced downwards, to show +its entire form; the * indicates the part of the cranium to which the +condyle is articulated.[9]] + +In addition to the bones already mentioned as entering into the formation +of the cranium, there are many others, the most important of which may +be briefly noticed. The anterior extremity of the skull is formed by the +premaxillæ (Figs. 6, 7, _PMx_), which carry the incisors; behind them +are the maxillæ, in which all the remaining upper teeth are implanted. +Both the premaxillæ and maxillæ meet in a median suture on the palate, +where they form a floor to the nasal passage; this floor being continued +backwards by the plate-like palatines, at the hinder extremity of which +the posterior nares are usually situated. In a few instances, however, +as in certain Edentates and Cetaceans, the small pair of bones forming +the posterior continuation of the lateral borders of the palatines, and +known as the pterygoids (Fig. 6, _Pt_), likewise meet in the middle line +below the nasal passage, and thus cause the aperture of the posterior +nares to be situated near the occiput. On the upper, or frontal aspect of +the cranium the paired nasals roof over the nasal passage and fill the +interval left between the premaxilla and maxilla of either side. Behind +the nasals and maxillæ, the anterior part of the brain-case is formed +by the large paired frontals (Figs. 6, 7, _Fr_), behind which are the +parietals, which may be of still larger size, and form the greater part +of the brain-case. A median interparietal ossification (Fig. 6, _IP_) +may divide the parietals posteriorly, and is itself articulated with the +supraoccipital, to the lateral borders of which the parietals are also +joined. The squamosal (Fig. 7, _Sq_) forms the lateral wall of the hinder +part of the brain-case, and articulates superiorly with the parietal, +and posteriorly with the exoccipital. The glenoid cavity (Fig. 8), for +the reception of the articular condyle of the mandible, is formed by the +inferior portion of the squamosal, at the point where it gives off the +zygomatic process to form the hinder portion of the zygomatic arch. The +middle portion of that arch is formed by the jugal, or malar bone (Fig. +7, _Ma_), which articulates posteriorly with the zygomatic process of +the squamosal, and anteriorly with the maxilla. The jugal (as in Fig. 7) +may also articulate with a small bone situated on the anterior border +of the orbit known as the lachrymal. It is important to observe that +the zygomatic or temporal arch is a squamoso-maxillary one, and that an +arcade thus composed is found elsewhere only among the extinct Anomodont +reptiles, which have already been mentioned as showing signs of mammalian +affinity. The relative position occupied by the orbito- and alisphenoid +is sufficiently indicated in Fig. 7. + +[Illustration: FIG. 7.—Side view of skull of Cape Jumping Hare (_Pedetes +caffer_). × ⅗ _PMx_, Premaxilla; _Mx_, maxilla, _Ma_, jugal or malar; +_Fr_, frontal; _L_, lachrymal; _Pa_, parietal; _Na_, nasal; _Sq_, +squamosal; _Ty_, tympanic; _ExO_, exoccipital; _AS_, alisphenoid; _OS_, +orbitosphenoid; _Per_, mastoid bulla.] + +Wedged in between the squamosal and the bones of the occipital and +basisphenoidal region are the bones connected with the organ of hearing, +known as the periotic and tympanic. The position of the periotic, which +encloses the labyrinth or essential organ of hearing, is shown in Fig. 6. +The periotic is divided into a very dense antero-internal moiety known as +the petrosal, and a postero-external or mastoid portion (Fig. 8), which +appears on the outer wall of the brain-case. The tympanic is produced +horizontally outwards to form the external auditory meatus or tube of +the ear, while the inner and under surface is frequently dilated into a +shell-like auditory bulla (Fig. 8). The small bones of the internal ear +known as the malleus, incus, and stapes are contained in the membranous +_tympanic cavity_, which is situated in a space left among this group of +bones. Further mention of these bones is made below under the head of the +sense organs. + +In the Carnivora and some other groups the foramina on the base of the +skull for the passage of blood-vessels and nerves are of considerable +taxonomic importance. The position of the more important of these +foramina is indicated in Fig. 8; but for details the reader may refer to +the work on the _Osteology of the Mammalia_ already mentioned. Attention +may, however, be particularly directed to the so-called alisphenoid +canal, the position of which is shown in Fig. 8, since this is a feature +of some importance in the classification of the Carnivora. This canal +is a short channel running horizontally forward from near the foramen +ovale through the alisphenoid, and opening anteriorly with the foramen +rotundum; it is traversed by the external carotid artery. + +[Illustration: FIG. 8.—The right half of the hinder part of the base +of the cranium of the Wolf (_Canis lupus_). _c_, Condyloid foramen; +_l_, foramen lacerum posticum; _car_, carotid canal; _e_, eustachian +canal; _o_, foramen ovale; _a_, posterior, and _a′_, anterior aperture +of alisphenoid canal; _P_, paroccipital process of exoccipital; _m_, +mastoid process of periotic; _am_, external auditory meatus; _g_, glenoid +foramen, below which is the glenoid cavity for the condyle of the +mandible. (Flower, _Proc. Zool. Soc._, 1869, p. 25.)] + +Only in those species, as Man and the smaller kinds of the Primates and +some other orders, in which the brain holds a large relative proportion +to the rest of the body, does the external form of the skull receive +much impress from the real shape of the cavity containing the brain. +The size and form of the mouth, and the modifications of the jaws for +the support of teeth of various shape and number, the ridges and crests +on the cranium for the attachment of the muscles necessary to put this +apparatus in motion, and outgrowths of bone for the enlargement of the +external surface required for the support of sense organs or of weapons, +such as horns or antlers (which outgrowths, to prevent undue increase +of weight, are filled with cells containing air), cause the principal +variations in the general configuration of the skull. These variations +are, however, only characteristically developed in perfectly adult +animals, and are in many cases more strongly marked in the male than the +female sex. Throughout all the later stages of growth up to maturity +the size and form of the brain-case remain comparatively stationary, +while the accessory parts of the skull rapidly increase and assume their +distinctive development characteristic of the species. + +The hyoidean apparatus in mammals (Fig. 6) supports the tongue and +larynx, and consists of an inferior median portion termed the basihyal, +from which two pairs of half arches, or cornua, extend upwards and +outwards. The anterior is the more important, being connected with the +periotic bone of the cranium. It may be almost entirely ligamentous, but +more often has several ossifications, the largest of which is usually the +stylohyal. The posterior cornu (thyrohyal) is united at its extremity +with the thyroid cartilage of the larynx, which it suspends in position. +The median portion, or basihyal, is sometimes, as in the Howling Monkeys, +enormously enlarged and hollowed, admitting into its cavity an air-sac +connected with the organ of voice. + +[Illustration: FIG. 9.—Anterior surface of Human thoracic vertebra +(fourth). _c_, Body or centrum; _nc_, neural canal; _p_, pedicle, +and _l_, lamina of the arch; _t_, transverse process; _az_, anterior +zygapophysis.] + +_Vertebral Column._—The _vertebral column_ consists of a series of +distinct bones called vertebræ, arranged in close connection with each +other along the dorsal side of the neck and trunk, and in the median +line.[10] It is generally prolonged posteriorly beyond the trunk, to +form the axial support of the appendage called the tail. Anteriorly it +is articulated with the occipital region of the skull. The number of +distinct bones composing the vertebral column varies greatly among the +Mammalia, the main variation being due to the degree of elongation of +the tail. Apart from this, in most mammals the number is not far from +thirty, though it may fall as low as twenty-six (as in some Bats), or +rise as high as forty (_Hyrax_ and _Cholœpus_). The different vertebræ, +with some exceptions, remain through life quite distinct from each other, +though closely connected by means of fibrous structures which allow of +a certain, but limited, amount of motion between them. The exceptions +are the following:—(1) near the posterior part of the trunk, in nearly +all mammals which possess completely developed hinder limbs, two or more +vertebræ become ankylosed together to form the “sacrum,” or portion of +the vertebral column to which the pelvic girdle is attached; (2) in some +species of Whales and Armadillos there are constant ossific unions of +certain vertebræ of the cervical region. + +[Illustration: FIG. 10.—Side view of the first lumbar vertebra of a Dog +(_Canis familiaris_). _s_, Spinous process; _az_, anterior zygapophysis; +_pz_, posterior zygapophysis; _m_, metapophysis; _a_, anapophysis; _t_, +transverse process.] + +Although the vertebræ of different regions of the column of the same +animal or of different animals present great diversities of form, yet +there is a certain general resemblance among them, or a common plan on +which they are constructed, which is more or less modified by alteration +of form or proportions, or by the addition or suppression of parts to +fit them to fulfil their special purpose in the economy. An ordinary or +typical vertebra consists, in the first place, of a solid piece of bone, +termed the body or centrum (Fig. 9, _c_), of the form of a disk or short +cylinder. The bodies of contiguous vertebræ are connected together by +a very dense, tough, and elastic material called the “intervertebral +substance,” of peculiar and complex arrangement. This substance forms +the main, and in some cases the only, union between the vertebræ. Its +elasticity provides for the vertebræ always returning to their normal +relation to each other and to the column generally, when they have been +disturbed therefrom by muscular action. A process (_p_) arises on each +side from the dorsal surface of the body. These processes, meeting +in the middle line above, form an arch, surmounting a space or short +canal (_nc_). Since it contains the posterior prolongation of the great +cerebro-spinal nervous axis, or spinal cord, this space is called the +neural canal, and the arch the neural arch, in contradistinction to +another arch on the ventral surface of the body of the vertebræ, called +the hæmal arch. The latter is, however, never formed in mammals by +any part of the vertebra itself, but by certain distinct bones placed +more or less in apposition to it, namely the ribs in the thoracic, and +the “chevron bones” in the caudal region. In most cases the arch of +one vertebra is articulated with that of the next by distinct surfaces +with synovial joints, placed one on each side, called “zygapophyses” +(_az_, _pz_), but these are often entirely wanting when flexibility is +more needed than strength, as in the greater part of the caudal region +of long-tailed animals. In addition to the body and the arch, there +are certain projecting parts called processes, chiefly serving for the +attachment of the numerous muscles which move the vertebral column. Of +these two are single and median, viz. the spinous process, neural spine, +or neurapophysis (_s_), arising from the middle of the upper part of +the arch, and the hypapophysis from the under surface of the body. The +latter, however, is as frequently absent as the former is constant. The +other processes are paired and lateral. They are the transverse processes +(_t_), of which there may be two, an upper and a lower, in which case the +former is called, in the language of Owen (to whom we are indebted for +the terminology of the parts of vertebræ in common use), “diapophysis,” +and the latter “parapophysis.” Other processes less constantly present +are called respectively “metapophyses” (_m_) and “anapophyses” (_a_). + +The vertebral column is divided for convenience of description into five +regions—the cervical, thoracic or dorsal, lumbar, sacral, and caudal. +This division is useful, especially as it is not entirely arbitrary, +and in most cases is capable of ready definition; but at the contiguous +extremities of the regions the characters of the vertebræ of one are +apt to blend into those of the next region, either normally or as +peculiarities of individual skeletons. + +[Illustration: FIG. 11.—Anterior surface of sixth cervical vertebra +of Dog. _s_, Spinous process; _az_, anterior zygapophysis; _v_, +vertebrarterial canal; _t_, transverse process; _t′_, its inferior +lamella.] + +_Cervical Vertebræ._—The _cervical_ region constitutes the most anterior +portion of the column, or that which joins the cranium. The vertebræ +which belong to it are either entirely destitute of movable ribs, or +if they have any these are small, and do not join the sternum. As a +general rule they have a considerable perforation through the base +of the transverse process (the vertebrarterial canal, Fig. 11, _v_); +or, as it is sometimes described, they have two transverse processes, +superior and inferior, which meet at their extremities to enclose a +canal. This, however, rarely applies to the last vertebra of the region, +in which only the upper transverse process is usually developed. The +transverse process, moreover, very often sends down near its extremity +a more or less compressed plate (inferior lamella), which, being +considered serially homologous with the ribs of the thoracic vertebræ +(though not developed autogenously), is often called the “costal” or +“pleurapophysial” plate. This is usually largest on the sixth, and +altogether wanting on the seventh vertebra. The first and second cervical +vertebræ, called respectively “atlas” and “axis,” are specially modified +for the function of supporting and permitting the free movements of the +head. They are not united together by the intervertebral substance, but +connected only by ordinary ligaments and synovial joints. + +The cervical region in mammals presents the remarkable peculiarity that, +whatever the length or flexibility of the neck, the number of vertebræ +is the same, viz. seven, with the exception of the Manatee and Hoffman’s +Two-toed Sloth (_Cholœpus hoffmanni_), which both have but six, and +the Three-toed Sloth (_Bradypus tridactylus_), which has nine, though +in this case the last two usually support movable ribs, which are not +sufficiently developed to reach the sternum. + +According to Parker there may occasionally be eight cervicals in the +Pangolins (_Manis_). + +_Dorsal Vertebræ._—The _dorsal_ (or, as it would be more correctly +termed, _thoracic_) region consists of the vertebræ succeeding those of +the neck, which have ribs movably articulated to them. These ribs arch +round the thorax—the anterior one, and usually the greater number of +those that follow, being attached below to the sternum. + +_Lumbar Vertebræ._—The _lumbar_ region consists of those vertebræ of +the trunk in front of the sacrum which bear no movable ribs. It may +happen that, as the ribs decrease in size posteriorly (the last being +sometimes more or less rudimentary), the step from the thoracic to +the lumbar region may be gradual and rather undetermined in a given +species; but most commonly this is not the case, and the distinction is +as well defined here as in any other region. As a general rule there +is a certain relation between the number of the thoracic and lumbar +vertebræ, the whole number being tolerably constant in a given group +of animals, and any increase of the one being at the expense of the +other. Thus in all known Artiodactyle Ungulata there are 19 dorso-lumbar +vertebræ; but these may consist of 12 dorsal and 7 lumbar vertebræ, or +13 dorsal and 6 lumbar, or 14 dorsal and 5 lumbar. The smallest number +of dorso-lumbar vertebræ in mammals occurs in some Armadillos, which +have but 14. The number found in Man, the higher Apes, and most Bats, +viz. 17, is exceptionally low; 19 prevails in the Artiodactyla, nearly +all Marsupials, and very many Rodents; 20 or 21 in Carnivora and most +Insectivora; and 23 in Perissodactyla. The highest and quite exceptional +numbers are in the Two-toed Sloth (_Cholœpus_) 27, and the Hyrax 30. The +prevailing number of rib-bearing vertebræ is 12 or 13, any variation +being generally in excess of these numbers. + +_Sacral Vertebræ._—The _sacral_ region offers more difficulties of +definition. Taking the human “os sacrum” as a guide for comparison, +it is generally defined as consisting of those vertebræ between the +lumbar and caudal regions which are ankylosed together to form a single +bone. It happens, however, that the number of such vertebræ varies in +different individuals of the same or nearly allied species, especially +as age advances, when a certain number of the tail vertebræ generally +become incorporated with the true sacrum. Other suggested tests—as those +vertebræ which have a distinct additional (pleurapophysial) centre of +ossification between the body and the ilium, those to which the ilium +is directly articulated, or those in front of the insertion of the +ischiosacral ligaments—being equally unsatisfactory or unpractical, the +old one of ankylosis, as it is found to prevail in the average condition +of adults in each species, is used in the enumeration of the vertebræ in +the following pages. The Cetacea, having no iliac bones, have no part of +the vertebral column modified into a sacrum. + +[Illustration: FIG. 12.—Anterior surface of fourth caudal vertebræ of +Porpoise (_Phocæna communis_). _s_, Spinous process; _m_, metapophysis; +_t_, transverse process; _h_, chevron bone.] + +_Caudal Vertebræ._—The _caudal_ vertebræ are those placed behind the +sacrum, and terminating the vertebral column. They vary in number +greatly—being reduced to 5, 4, or even 3, in a most rudimentary +condition, in Man and in some Apes and Bats, and being numerous and +powerfully developed, with strong and complex processes, in many mammals, +especially among the Edentata, Cetacea, and Marsupialia. The highest +known number, 46, is possessed by the African Long-tailed Pangolin. +Connected with the under surface of the caudal vertebræ of many mammals +which have the tail well developed are certain bones formed more or less +like an inverted arch, called chevron bones, or by the French _os en V_. +These are always situated nearly opposite to an intervertebral space, and +are generally articulated both to the vertebra in front and the vertebra +behind, but sometimes chiefly or entirely either to one or the other. + +In some of the Anomodont Reptiles and Labyrinthodont Amphibians these +chevrons are attached to the intercentra—or imperfect disks alternating +with the true centra—which suggests that they are primarily intercentral +elements which have been transferred to the edges of the centra by the +disappearance of the intercentra. + +_Sternum._—The _sternum_ of mammals is a bone, or generally a series +of bones, placed longitudinally in the mesial line, on the inferior +or ventral aspect of the thorax, and connected on each side with the +vertebral column by a series of more or less ossified bars called “ribs.” +It is present in all mammals, but varies much in character in the +different groups. It usually consists of a series of distinct segments +placed one before the other, the anterior being called the presternum or +“manubrium sterni” of human anatomy, and the posterior the xiphisternum, +or xiphoid or ensiform process, while the intermediate segments, whatever +their number, constitute the mesosternum or “body.” In the Whalebone +Whales the presternum alone is developed, and but a single pair of ribs +is attached to it. + +[Illustration: FIG. 13.—Human sternum and sternal ribs. _ps_, Presternum; +_ms_, mesosternum; _xs_, xiphisternum; _c_, point of attachment of +clavicle; 1 to 10, the cartilaginous sternal ribs.] + +_Ribs._—The _ribs_ form a series of long, narrow, and more or less +flattened bones, extending laterally from the sides of the vertebral +column, curving downwards towards the median line of the body below, and +mostly joining the sides of the sternum. The posterior ribs, however, +do not directly articulate with that bone, but are either attached by +their extremities to the edges of each rib in front of them, and thus +only indirectly join the sternum, or else they are quite free below, +meeting no part of the skeleton. These differences have given rise to the +division into “true” and “false” ribs (by no means good expressions), +signifying those that join the sternum directly and those that do not; +and of the latter, those that are free below, are called “floating” ribs. +The portion of each rib nearest the vertebral column and that nearest +the sternum differ in their characters, the latter being usually but +imperfectly ossified, or remaining permanently cartilaginous. These are +called “costal cartilages,” or when ossified “sternal ribs.” + +[Illustration: FIG. 14.—Sternum and strongly ossified sternal ribs of +Great Armadillo (_Priodon gigas_). _ps_, Presternum; _xs_, xiphisternum.] + +In the anterior part of the thorax the vertebral extremity of each rib is +divided into two parts, “head” or “capitulum,” and “tubercle”; the former +is attached to the side of the body of the vertebra, the latter to its +transverse process; the former attachment corresponds to the interspace +between the vertebræ, the head of the rib commonly articulating partly +with the hinder edge of the body of the vertebra antecedent to that which +bears its tubercle. Hence the body of the last cervical vertebra usually +supports part of the head of the first rib. In the posterior part of the +series the capitular and tubercular attachments commonly coalesce, and +the rib is attached solely to its corresponding vertebra. The number of +pairs of ribs is of course the same as that of the thoracic vertebræ. + +The circumstance that in some of the Anomodont reptiles and +Labyrinthodonts the capitula of the ribs articulate with the intercentral +elements of the vertebral column has suggested, as in the instance of +the chevron bones, that the intercentral capitular articulation of the +ribs of mammals is a feature directly inherited from those extinct types +by the gradual disappearance of the intercentra. + +_Appendicular Skeleton._—The appendicular portion of the framework +consists, when completely developed, of two pairs of limbs, anterior and +posterior (Fig. 15). + +[Illustration: FIG. 15.—Skeleton of Lion (_Felis leo_). _cd_, Caudal +vertebræ; _cp_, carpus; _cr_, coracoid process of scapula, _cv_, cervical +vertebræ; _d_, dorsal vertebræ; _fb_, fibula; _fm_, femur; _h_, humerus; +_il_, ilium; _isch_, ischium; _l_, lumbar vertebræ; _m_, metatarsus; +_mc_, metacarpus; _p_, patella; _pb_, pubis; _ph_, phalanges; _pv_, +pelvis; _r_, radius; _s_, sacral vertebræ; _sc_, scapula; _sk_, skull; +_tb_, tibia; _ts_, tarsus; _u_, ulna; _zy_, zygomatic arch.] + +_Anterior Limb._—The anterior limb is present and fully developed in all +mammals, being composed of a shoulder girdle and three segments belonging +to the limb proper; viz. the upper arm or brachium, the forearm or +antebrachium, and the hand or manus. + +_Shoulder-girdle._—The _shoulder_ or _pectoral girdle_ in the large +majority of mammals is in a rudimentary or rather modified condition, +compared with that in which it exists in other vertebrates. In the +Monotremata (_Ornithorhynchus_ and _Echidna_) alone is the ventral +portion, or coracoid, complete and articulated with the sternum below, +as in the Sauropsida; and in this group alone do we find an anterior +ventral element, apparently corresponding with the pre-coracoid of the +Anomodont reptiles, although generally known as the epi-coracoid. In +all other mammals the coracoid, though ossified from a distinct centre, +forms only a process, sometimes a scarcely distinct tubercle, projecting +from the anterior border of the glenoid cavity of the scapula. The +last-named cavity, which in the Monotremes is formed jointly by the +scapula and coracoid, receives the head of the humerus, or arm-bone. The +scapula is always well developed, and generally broad and flat (whence +its vernacular name “blade bone”), with a ridge called the “spine” on +its outer surface, which usually ends in a free curved process, the +“acromion.” As the scapula affords attachment to many of the muscles +which act upon the anterior limb, its form and the development of its +processes are greatly modified according to the uses to which the +member is put. Thus it is most reduced and simple in character in those +animals whose limbs are mere organs of support, as the Ungulates; and +most complex when the limbs are also used for grasping, climbing, or +digging. The development or absence of the clavicle or “collar-bone,” +an accessory bar which connects the sternum with the scapula and +steadies the shoulder-joint, has a somewhat similar relation, though +its complete absence in the Bears shows that this is not an invariable +rule. A complete clavicle is found in Man and all the Primates, in +Chiroptera, all Insectivora (except _Potamogale_), in many Rodents, in +most Edentates, and in all Marsupials, except _Perameles_. More or less +rudimentary clavicles (generally suspended freely in the muscles) are +found in the Cat, Dog, and most Carnivora, _Myrmecophaga_, and some +Rodents. Clavicles are altogether absent in most of the _Ursidæ_, all the +Pinnipedia, _Manis_ among Edentates, the Cetacea, Sirenia, Ungulates, and +some Rodents. + +The Monotremes are peculiar in possessing a T-shaped interclavicle +like that of many reptiles, lying upon the sternum, and articulating +superiorly with the clavicles. + +_Brachium and Antebrachium._—The proximal segment of the anterior or +pectoral limb proper contains a single bone, the humerus, and the second +segment two bones, the radius and the ulna, placed side by side, and +articulating with the humerus at their proximal, and with the carpus +at their distal extremity (Fig. 15). In their primitive and unmodified +condition these bones may be considered as placed one on each border of +the limb, the radius being preaxial or anterior, and the ulna postaxial +or posterior, when the distal or free end of the limb is directed +outwards, or away from the trunk. This is their position in the earliest +embryonic condition, and is best illustrated among adult mammals in the +Cetacea, where the two bones are fixed side by side and parallel to each +other. In the greater number of mammals the bones assume a very modified +and adaptive position, usually crossing each other in the forearm, the +radius in front of the ulna, so that the preaxial bone (radius), though +external (in the ordinary position of the limb) at the upper end, is +internal at the lower end; and the hand, being mainly fixed to the +radius, also has its preaxial border internal. In the large majority of +mammals the bones are fixed in this position, but in some few, as in Man, +a free movement of crossing and uncrossing—or pronation and supination, +as it is termed—is allowed between them, so that they can be placed in +their primitive parallel condition, when the hand (which moves with the +radius) is said to be supine, or they may be crossed, when the hand is +said to be prone. + +The humerus frequently has a foramen piercing the inner border of the +distal extremity, known as the entepicondylar foramen, which corresponds +with a similar one found in the Anomodont reptiles. The hollow in the +head of the ulna for the reception of the head of the humerus is known as +the greater sigmoid cavity, and that for the head of the radius as the +lesser sigmoid cavity (Fig. 16). The term olecranon is applied to that +process of the ulna which forms the prominence of the elbow. + +[Illustration: FIG. 16.—Outer aspect of the proximal extremity of the +right ulna of a Bear (_Ursus_). _a_, Anterior tubercle; _ol_, olecranon; +_b_, greater sigmoid cavity; _c_, lesser do.] + +In most mammals walking on four limbs, in which the hand is permanently +prone, the ulna is much reduced in size, and the radius increased, +especially at the upper end; so that the articular surface of the latter, +instead of being confined to the external side of the trochlea of the +humerus, extends all across its anterior surface, and the two bones, +instead of being external and internal, are anterior and posterior. In +many hoofed or Ungulate mammals, and in Bats, the ulna is reduced to +little more than its upper articular extremity, and firmly ankylosed to +the radius—stability of these parts being more essential than mobility. + +_Manus._—The terminal segment of the anterior limb is the hand or +manus. Its skeleton consists of three divisions: (1) the “carpus,” a +group of small, more or less rounded or angular bones with flattened +surfaces applied to one another, and, though articulating by synovial +joints, having scarcely any motion between them; (2) the “metacarpus,” +a series of elongated bones placed side by side, with their proximal +ends articulating by almost immovable joints with the carpus; (3) the +“phalanges” or bones of the digits, usually three in number to each, +articulating to one another by freely movable hinge-joints, the first +being connected in like manner to the distal end of the metacarpal bone +to which it corresponds. + +[Illustration: FIG. 17.—Dorsal surface of the right manus of a Water +Tortoise (_Chelydra serpentina_). After Gegenbaur. U, Ulna; R, radius; +_u_, ulnare; _i_, intermedium; _r_, radiale; _c_, centrale; 1-5, the five +bones of the distal row of the carpus; _m¹_-_m⁵_, the five metacarpals.] + +_Carpus._—To understand thoroughly the arrangement of the bones of the +carpus in mammals, it is necessary to study their condition in some of +the lower vertebrates. Fig. 17 represents the manus in one of its fullest +and at the same time most generalised forms, as seen in one of the Water +Tortoises (_Chelydra serpentina_). The carpus consists of two principal +rows of bones. The upper or proximal row contains three bones, to which +Gegenbaur has applied the terms _radiale_ (_r_), _intermedium_ (_i_), and +_ulnare_ (_u_), the first being on the radial or preaxial side of the +limb.[11] The lower or distal row contains five bones, called _carpale_ +1, 2, 3, 4, and 5 respectively, commencing on the radial side. Between +these two rows, in the middle of the carpus, is a single bone, the +_centrale_ (_c_). In this very symmetrical carpus it will be observed +that the _radiale_ supports on its distal side two bones, _carpale_ 1 +and 2; the _intermedium_ is in a line with the _centrale_ and _carpale_ +3, which together form a median axis of the hand, while the _ulnare_ has +also two bones articulating with its distal end, viz. _carpale_ 4 and 5. +Each of the carpals of the distal row supports a metacarpal. + +In the carpus of the Mammalia there are usually two additional bones +developed in the tendons of the flexor muscles, one on each side of the +carpus, which may be called the radial and ulnar sesamoid bones; the +latter, which is the more constant and generally larger, is commonly +known as the pisiform bone. The fourth and fifth carpals of the distal +row are always united into a single bone, and the centrale is very often +absent. As a general rule all the other bones are present and distinct, +though it not unfrequently happens that two may have coalesced to form a +single bone, or one or more may be altogether suppressed. + +The following table shows the principal names in use for the various +carpal bones,—those in the second column being the terms generally +employed by English anatomists:— + + _Radiale_ = Scaphoid = _Naviculare_. + _Intermedium_ = Lunar = _Semilunare_, _Lunatum_. + _Ulnare_ = Cuneiform = _Triquetrum_, _Pyramidale_. + _Centrale_ = Central = _Intermedium_ (Cuvier). + _Carpale_ 1 = Trapezium = _Multangulum majus_. + _Carpale_ 2 = Trapezoid = _Multangulum minus_. + _Carpale_ 3 = Magnum = _Capitatum_. + _Carpale_ 4 } = Uneiform = _Hamatum_, _Uncinatum_. + _Carpale_ 5 } + +The radial and ulnar sesamoids are regarded by Bardeleben[12] as the +rudiments of a prepollex and a postminimus digit; the primitive number +of digits being thus supposed to have been seven. These bones have +been observed in all orders of mammals having five complete digits. +Occasionally, as in _Pedetes caffer_, the so-called prepollex consists +of two bones, of which the distal one bears a distinct nail-like horny +covering. In _Bathyergus maritimus_ the pisiform, or postminimus, is +likewise double; the two elements being regarded by their describer as +representing the carpal and metacarpal of the presumed seventh digit. + +Similarly in the posterior limb the tibial sesamoid, and a fibular +ossification corresponding to the pisiform, are regarded as representing +a prehallux and a postminimus. + +_Metacarpus and Phalanges._—The metacarpal bones, with the digits which +they support, are never more than five in number, and are described +numerically—first, second, etc., counting from the radial towards the +ulnar side. The digits are also sometimes named (1) the pollex, (2) +index, (3) medius, (4) annularis, (5) minimus. One or more may be in +a rudimentary condition, or altogether suppressed. If one is absent, +it is most commonly the first. Excepting the Cetacea, no mammals have +more than three phalanges to each digit, but they may occasionally have +fewer by suppression or ankylosis. The first or radial digit is an +exception to the usual rule, one of its parts being constantly absent, +since, while each of the other digits has commonly a metacarpal and +three phalanges, it has only three bones altogether; whether the missing +one is a metacarpal or one of the phalanges is a subject which has +occasioned much discussion, and has not yet been satisfactorily decided. +The terminal phalanges of the digits are usually specially modified to +support the nail, claw, or hoof, and are called “ungual phalanges.” In +walking, some mammals (as the Bears) apply the whole of the lower surface +of the carpus, metacarpus, and phalanges to the ground; to these the +term “plantigrade” is applied. Many others (as nearly all the existing +Ungulata) only rest on the last one or two phalanges of the toes, the +first phalanx and the metacarpals being vertical and in a line with the +forearm. These are called “digitigrade.” Intermediate conditions exist +between these two forms, to which the terms “phalangigrade” (as the +Camel) and “subplantigrade” (as in most Carnivora), are applied. When the +weight is borne entirely on the distal surface of the ungual phalanx, +and the horny structures growing around it, as in the Horse, the mode of +progression is called “unguligrade.” + +In the Chiroptera the digits are enormously elongated, and support a +cutaneous expansion constituting the organ of flight. In the Cetacea the +manus is formed into a paddle, being covered by continuous integument, +which conceals all trace of division into separate digits, and shows no +sign of nails or claws. In the Sloths the manus is long and very narrow, +habitually curved, and terminating in two or three pointed curved claws +in close apposition with each other, and incapable, in fact, of being +divaricated; so that it is reduced to the condition of a hook, by which +the animal suspends itself to the boughs of the trees among which it +lives. These are only examples of the endless modifications to which the +distal extremity of the limb is subjected in adaptation to the various +purposes to which it is applied. + +_Posterior Limb._—The posterior limb is constructed upon a plan very +similar to that of the anterior extremity. It consists of a pelvic girdle +and three segments belonging to the limb proper, viz. the thigh, the leg, +and the foot or pes (Fig. 15). + +_Pelvic Girdle._—The pelvic girdle is present in some form in all +mammals, though in the Cetacea and the Sirenia it is in an exceedingly +rudimentary condition. In all mammals except those belonging to the +two orders just named, each lateral half of the pelvic girdle consists +essentially, like the corresponding part of the anterior limb, of a +flattened rod of bone crossing the long axis of the trunk, having an +upper or dorsal and a lower or ventral end. The upper end diverges from +that of the opposite side, but the lower end approaches, and, in most +cases, meets it, forming a symphysis, without the intervention of any +bone corresponding to the sternum. The pelvic girdle differs from the +shoulder girdle in being firmly articulated to the vertebral column, thus +giving greater power to the hinder limb in its function of supporting +and propelling the body. Like the shoulder girdle, it bears on its outer +side, near the middle, a cup-shaped articular cavity (“acetabulum”), +into which the proximal end of the first bone of the limb proper is +received. Each lateral half of the girdle is called the “os innominatum,” +or innominate bone, and consists originally of three bones which unite +at the acetabulum. The “ilium” or upper bone is that which articulates +with the sacral vertebræ. Of the two lower bones the anterior or “pubis” +unites with its fellow of the other side at the symphysis; the posterior +is the “ischium.” These lower elements form two bars of bone, united +above and below, but leaving a space between them in the middle, filled +only by membrane, and called the “thyroid” or “obturator” foramen. The +whole circle of bone formed by the two innominate bones and the sacrum +is called the pelvis. In the Monotremata and Marsupialia, a pair of +thin, flat, elongated ossifications called epipubic or marsupial bones +are attached to the fore part of the pubis, and project forward into the +muscular wall of the abdomen. + +_Thigh and Leg._—The first segment of the limb proper has one bone, the +femur, corresponding with the humerus of the anterior limb. The second +segment has two bones, the tibia and fibula, corresponding with the +radius and ulna. These bones always lie in their primitive unmodified +position, parallel to each other, the tibia on the preaxial and the +fibula on the postaxial side, and are never either permanently crossed or +capable of any considerable amount of rotation, as in the corresponding +bones of the fore limb. In the ordinary walking position the tibia is +internal, and the fibula external. In many mammals the fibula is in a +more or less rudimentary condition, and it often ankyloses with the tibia +at one or both extremities. The patella or “knee-cap,” which is found +in an ossified condition in all mammals, with the exception of some of +the Marsupialia, is a large sesamoid bone developed in the tendon of the +extensor muscles of the thigh, where the tendon passes over the front of +the knee-joint, to which it serves as a protection. There are frequently +smaller ossicles, one or two in number, situated behind the femoral +condyles, called “fabellæ.” The processes for the attachment of muscles +near the upper end of the femur are termed trochanters; and the third +trochanter, found on the hinder aspect of the shaft of this bone in many +forms is of considerable taxonomic importance. + +_Pes._—The terminal segment of the hind limb is the foot or pes. Its +skeleton presents in many particulars a close resemblance to that of +the manus, being divisible into three parts: (1) a group of short, more +or less rounded or square bones, constituting the tarsus; (2) a series +of long bones placed side by side, forming the metatarsus; and (3) the +phalanges of the digits or toes. + +The bones of the tarsus of many of the lower Vertebrata closely resemble +both in number and arrangement those of the carpus, as shown in Fig. 17. +They have been described in their most generalised condition by Gegenbaur +under the names expressed in the first column of the following table. The +names in the second column are those by which they are generally known to +English anatomists, while in the third column some synonyms occasionally +employed are added. + + _Tibiale (?)_ } = Astragalus[13] = _Talus_. + _Intermedium_ } + _Fibulare_ = Calcaneum = _Os calcis_. + _Centrale_ = Navicular = _Scaphoideum_. + _Tarsale_ 1 = Internal cuneiform = _Entocuneiforme_. + _Tarsale_ 2 = Middle cuneiform = _Mesacuneiforme_. + _Tarsale_ 3 = External cuneiform = _Ectocuneiforme_. + _Tarsale_ 4 } = Cuboid. + _Tarsale_ 5 } + +The bones of the tarsus of mammals present fewer diversities of number +and arrangement than those of the carpus. The proximal row (see Fig. +18) always consists of two bones, namely the astragalus (_a_), which +probably represents the coalesced scaphoid and lunar of the hand, and the +calcaneum (_c_). The former is placed more to the dorsal side of the foot +than the latter, and almost exclusively furnishes the tarsal part of the +tibio-tarsal or ankle-joint. The calcaneum, placed more to the ventral +or “plantar” side of the foot, is elongated backwards to form a more or +less prominent tuberosity, the “tuber calcis,” to which the tendon of +the great extensor muscles of the foot is attached. The navicular bone +(_n_) is interposed between the proximal and distal row on the inner +or tibial side of the foot, but on the outer side the bones of the two +rows come into contact. The distal row, when complete, consists of four +bones, which, beginning on the inner side, are the three cuneiform bones, +internal (_c¹_), middle (_c²_), and external (_c³_), articulated to the +distal surface of the navicular, and the cuboid (_cb_), articulated with +the calcaneum. Of these the middle cuneiform is usually the smallest in +animals in which all five digits are developed; but when the hallux is +wanting the internal cuneiform may be rudimentary or altogether absent. +The three cuneiform bones support respectively the first, second, and +third metatarsals, and the cuboid supports the fourth and fifth; they +thus exactly correspond with the four bones of the distal row of the +carpus. + +[Illustration: FIG. 18.—Bones of the right Human foot. _T_, Tarsus; _M_, +metatarsus; _Ph_, phalanges, _c_, calcaneum; _a_, astragalus; _cb_, +cuboid; _n_, navicular; _c¹_, internal cuneiform; _c²_, middle cuneiform; +_c³_, external cuneiform. The digits are indicated by Roman numerals, +counting from the tibial to the fibular side.] + +In addition to these constant tarsal bones, there may be supplemental +or sesamoid bones: one situated near the middle of the tibial side of +the tarsus, largely developed in many Carnivora and Rodentia; another, +less frequent, on the fibular side; and a third, often developed in the +tendons of the plantar surface of the tarsus, is especially large in +Armadillos. There is also usually a pair of sesamoid bones on the plantar +aspect of each metatarso-phalangeal articulation. In the young of the +carnivorous genus _Crytoprocta_ there may be a second centrale, which +usually coalesces with the ectocuneiform. + +The metatarsal bones never exceed five in number, and the phalanges +follow the same numerical rule as in the manus, never exceeding three in +each digit. Moreover, the first digit, counting from the tibial side, or +hallux, resembles the pollex of the hand in always having one segment +less than the other digits. As the function of the hind foot is more +restricted than that of the hand the modifications of its structure are +less striking. In the Cetacea and the Sirenia it is entirely wanting, +though in some existing members of the first-named order rudiments of +the bones of both the first and second segments of the limb have been +detected, and a femur is present in the Miocene Sirenian _Halitherium_. + + +IV. THE DIGESTIVE SYSTEM. + +_General Considerations._—The search after the purpose which every +modification of structure subserves in the economy is always full of +interest, and, if conducted with due caution and sufficient knowledge of +all the attendant circumstances, may lead to important generalisations. +It must always be borne in mind, however, that adaptation to its special +function is not the only cause of the particular form or structure of an +organ, but that this form, having in all probability been arrived at by +the successive and gradual modification of some other different form from +which it is now to a greater or less degree removed, has other factors +besides use to be taken into account. In no case is this principle so +well seen as in that of the organs of digestion. These may be considered +as machines which have to operate upon alimentary substances in very +different conditions of mechanical and chemical combination, and to +reduce them in every case to the same or precisely similar materials; +and we might well imagine that the apparatus required to produce flesh +and blood out of coarse fibrous vegetable substances would be different +from that which had to produce exactly the same results out of ready-made +flesh or blood; and in a very broad sense we find that this is so. Thus, +if we take a large number of carnivorous animals, belonging to different +fundamental types, and a large number of herbivorous animals, and strike +a kind of average of each, we shall find that there is, pervading the +first group, a general style, if we may use the expression, of the +alimentary organs, different from that of the others. That is to say, +there is a specially carnivorous and a specially herbivorous modification +of these parts. But, if function were the only element which has guided +such modification, it might be inferred that, as one form must be +supposed to be best adapted in its relation to a particular kind of diet, +that form would be found in all the animals consuming such diet. But this +is far from being the case. Thus the Horse and the Ox, for instance—two +animals whose food in the natural state is precisely similar—are most +different as regards the structure of their alimentary canal, and the +processes involved in the preparation of that food. Again, the Seal and +the Porpoise, both purely fish-eaters, which seize, swallow, and digest +precisely the same kind of prey, in precisely the same manner, have a +totally different arrangement of the alimentary canal. If the Seal’s +stomach is adapted in the best conceivable manner for the purpose it has +to fulfil, why is not the Porpoise’s stomach an exact facsimile of it, +and _vice versâ_? We can only answer that the Seal and Porpoise belong to +different natural groups of animals, formed either on different primitive +types, or descended from differently constructed ancestors. On this +principle only can we account for the fact that, whereas, owing to the +comparatively small variety of the different alimentary substances met +with in nature, few modifications would appear necessary in the organs of +digestion, there is really endless variety in the parts devoted to this +purpose. + +_Mouth._—The digestive apparatus of mammals, as in other vertebrates, +consists mainly of a tube with an aperture placed at or near either +extremity of the body,—the oral and the anal orifice,—and furnished with +muscular walls, the fibres of which are so arranged as by their regular +alternate contraction and relaxation to drive onwards the contents of +the tube from the first to the second of these apertures. The anterior +or commencing portion of this tube and the parts around it are greatly +and variously modified in relation to the functions assigned to them of +selecting and seizing the food, and preparing it by various mechanical +and chemical processes for the true digestion which it has afterwards +to undergo before it can be assimilated into the system. For this end +the tube is dilated into a chamber or cavity called the mouth, bordered +externally by the lips, which are usually muscular and prehensile, and +supported by a movable framework carrying the teeth; the structure and +modifications of which have been already described. The roof of the mouth +is formed by the palate, terminating behind by a muscular, contractile +arch, having in Man and some few other species a median projection +called the uvula, beneath which the mouth communicates with the pharynx. +The anterior part of the palate is composed of mucous membrane tightly +stretched over the flat or slightly concave bony lamina separating the +mouth from the nasal passages, and is generally raised into a series +of transverse ridges, which sometimes, as in Ruminants, attain a +considerable development. In the floor of the mouth, between the rami of +the mandible, and supported behind by the hyoidean apparatus, lies the +tongue; an organ the free surface of which, especially in its posterior +part, is devoted to the sense of taste, but which also, by its great +mobility (being composed almost entirely of muscular fibres), performs +important mechanical functions connected with masticating and procuring +food. Its modifications of form in different mammals are very numerous. +Between the long, extensile, vermiform tongue of the Anteaters, which +is essential to the peculiar mode of feeding of those animals, and the +short, sessile, and almost functionless tongue of the Porpoise, every +intermediate condition is found. Whatever the form, the upper surface +is always covered with numerous fine papillæ, in which the terminal +filaments of the gustatory nerve are distributed. + +_Salivary Glands._—The fluid known as the saliva is secreted by an +extensive and complex system of glands discharging into the cavity of the +mouth (buccal cavity), the position and relation of some of which are +exhibited in the woodcut on the next page (Fig. 19). + +[Illustration: FIG. 19.—Salivary Glands of the Genet. _A_, Right side +of the head dissected; _p_, parotid gland; _d_, Steno’s duct; _sm_, +submaxillary gland, traversed by the jugular veins (_jv_); _o_, aperture +of Steno’s duct. _B_, Part of the head with the lip drawn up to show +(_st.d_) aperture of Steno’s duct; _z.gl_, zygomatic gland; _o_, aperture +of do.; _z_, zygomatic arch (Mivart, _Proc. Zool. Soc._ 1882, p. 504.)] + +This apparatus consists of small glands embedded in the mucous membrane +or submucous tissue lining the cavity of the mouth, which are of two +kinds (the follicular and the racemose), and of others in which the +secreting structure is aggregated in distinct masses removed some +distance from the cavity; other tissues besides the lining membrane being +usually interposed, and pouring their secretion into the cavity by a +distinct tube or duct, which traverses the mucous membrane. To the latter +alone the name of “salivary glands” is ordinarily appropriated, although +the distinction between them and the smaller racemose glands is only one +of convenience for descriptive purposes, their structure being more or +less nearly identical; and, since the fluids secreted by all become mixed +in the month, their functions are, at all events in great part, common. +Under the name of salivary glands are commonly included—(1) the “parotid” +(_p_), situated very superficially on the side of the head, below or +around the cartilaginous external auditory meatus, and the secretion of +which enters the mouth by a duct (often called Steno’s or Stenson’s) +which crosses the masseter muscle and opens into the upper and back part +of the cheek (Fig. 19); and (2) the “submaxillary” (_sm_), situated in +the neck, near or below the angle of the mandible, and sending a long +duct (Wharton’s) forwards to open on the forepart of the floor of the +cavity of the mouth, below the apex of the tongue. These are the most +largely developed and constant of the salivary glands, being met with +in various degrees of development in almost all animals of the class. +Next in constancy are (3) “the sublingual,” closely associated with the +last-named, at all events in the locality in which the secretion is +poured out; and (4) the “zygomatic” (_z.gl_), found only in some animals +in the cheek, just under cover of the anterior part of the zygomatic +arch, its duct entering the buccal cavity near that of the parotid. + +The most obvious function common to the secretion of these various +glands, and to that of the smaller ones placed in the mucous membrane +of the lips, the cheeks, the tongue, the palate, and fauces, is the +mechanical one of moistening and softening the food, to enable it the +more readily to be tasted, masticated, and swallowed, though each kind of +gland may contribute in different manner and different degree to perform +this function. The saliva is, moreover, of the greatest importance in the +first stage or introduction to the digestive process, as it dissolves +or makes a watery extract of all soluble substances in the food, and +so prepares them to be further acted on by the more potent digestive +fluids met with subsequently in their progress through the alimentary +canal. In addition to these functions it seems now well established by +experiment that saliva serves in Man and many animals to aid directly +in the digestive process, particularly by its power of inducing the +saccharine transformation of amylaceous substances. As a general rule, +in mammals the parotid saliva is more watery in its composition, while +that of the submaxillaries, and still more the sublingual, contains +more solid elements and is more viscid;—so much so that some anatomists +consider the latter, together with the small racemose glands of the +cheeks, lips, and tongue, as mucous glands, retaining the name of +salivary only for the parotid. These peculiar properties are sometimes +illustrated in a remarkable degree, as, for example, the great secretion +of excessively viscid saliva which lubricates the tongue of the Anteaters +and Armadillos, associated with enormously developed submaxillary glands; +while, on the other hand, the parotids are of great size in those animals +which habitually masticate dry and fibrous food. + +_Stomach._—After the preparation which the aliment has undergone in the +mouth,—the extent of which varies immensely in different forms, being +reduced almost to nothing in such animals as the Seals and Cetaceans, +which, to use the familiar expression, “bolt” their food entire, and +most fully carried out in the Ruminants, which “chew the cud,”—it is +swallowed, and carried along the œsophagus by the action of its muscular +coats into the stomach. In the greater number of mammals this organ is a +simple saccular dilatation of the alimentary canal, as in Figs. 20, 21, +but in others it undergoes remarkable modifications and complexities. +The lining of the stomach is thickly beset with tubular glands, which +are generally considered to belong to two different forms, recognisable +by their structure, and different in their function—the most numerous +and important secreting the gastric juice (the active agent in stomachic +digestion), and hence called “peptic” glands, while the others are +concerned only in the elaboration of mucus. The relative distribution +of these glands in different regions of the walls of the stomach varies +greatly in different animals, and in many species there are large tracts +of the mucous membrane which do not secrete a fluid having the properties +of gastric juice, but often constitute more or less distinct cavities +devoted to storing and perhaps softening or otherwise preparing the +food for digestion. Sometimes there is a great aggregation of glands +forming distinct thickened patches of the stomach wall, as in the Beaver +and Koala, or even collected in pyriform pouches with a common narrow +opening into the cavity, as in the Manatee and the curious African Rodent +_Lophiomys_. The action of the gastric fluid is mainly exerted upon the +nitrogenous elements of the food, which it dissolves and modifies so as +to render them capable of undergoing absorption, effected partly by the +blood-vessels of the stomach, although the greater part, passes through +the pylorus, an aperture surrounded by a circular muscular valve, into +the intestinal canal. Here it comes in contact with the secretion of a +vast number of small glands called the crypts of Lieberkuhn, somewhat +similar to those of the stomach; and also of several special glands of a +different character, namely, the small racemose, duodenal, or Brunner’s +glands, the pancreas, and the liver; the position of the ducts of the two +latter organs being indicated in Fig. 20. + +[Illustration: FIG. 20.—Stomach and pancreas of the Genet. Posterior or +dorsal surface, _œ_, Œsophagus; _s_, pancreas; _pd_, pancreatic duct; +_bd_, biliary duct from the liver. (From Mivart, _Proc. Zool. Soc._ 1882, +p. 305.)] + +_Intestinal Canal._—The intestinal canal varies greatly in relative +length and capacity in different animals, and it also offers manifold +peculiarities of form, being sometimes a simple cylindrical tube of +nearly uniform calibre throughout, but more often subject to alterations +of form and capacity in different portions of its course,—the most +characteristic and constant being the division into an upper and +narrower, and lower and wider portion, called respectively the small +and the large intestine, the former being divided quite arbitrarily and +artificially into duodenum, jejunum, and ileum, and the latter into +colon and rectum. One of the most striking peculiarities of this part +of the alimentary canal is the frequent presence of a diverticulum or +blind pouch, the _caput cæcum coli_, as it was first called, a name +generally abbreviated into “cæcum,” situated at the junction of the large +and the small intestine, a structure presenting an immense variety of +development, from the smallest bulging of a portion of the side wall of +the tube to a huge and complex sac, greatly exceeding in capacity the +whole of the remainder of the alimentary canal. It is only in herbivorous +animals that the cæcum is developed to this great extent, and among +these there is a curious complementary relationship between the size +and complexity of this organ and that of the stomach. Where the latter +is simple the cæcum is generally the largest, and _vice versâ_. Both +the cæcum and colon are often sacculated, a disposition caused by the +arrangement of the longitudinal bands of muscular tissue in their walls; +but the small intestine is always smooth and simple-walled externally, +though its lining membrane often exhibits various contrivances for +increasing the absorbing surface without adding to the general bulk of +the organ, such as the numerous small villi by which it is everywhere +beset, and the more obvious transverse, longitudinal, or reticulating +folds projecting into the interior, met with in many animals, of which +the “valvulæ conniventes” of Man form well-known examples. + +[Illustration: FIG. 21.—Diagrammatic plan of the general arrangement of +the alimentary canal in a typical Mammal. _o_, Œsophagus; _st_, stomach; +_p_, pylorus; _s_, _s_, small intestine; (abbreviated); _c_, cæcum; _l_, +_l_, large intestine or colon, ending in _r_, the rectum.] + +Besides the crypts of Lieberkuhn found throughout the intestinal canal, +and the glands of Brunner confined to the duodenum, there are other +structures in the mucous membrane, about the nature of which there is +still much uncertainty, called “solitary” and “agminated” glands; the +latter being more commonly known by the name of “Peyer’s patches.” These +were formerly supposed to be secretory organs, which discharged some +kind of fluid into the intestine, but are now more generally considered +to belong to that group of structures of somewhat mysterious function +of which the lymphatic and lacteal glands are members. The solitary +glands are found scattered irregularly throughout the whole intestinal +tract; the agminated, on the other hand, are always confined to the small +intestine, and are most abundant in its lower part. They are subject to +great variation in number and in size, and even in different individuals +of the same species, and also differ in character at different periods of +life, becoming atrophied in old age. + +_Liver._—The distinct glands situated outside the walls of the intestinal +canal, but which pour their secretion into it, are the pancreas and the +liver. The latter is the more important on account of its size, if not on +account of the direct action of its secretion in the digestive process. +This large gland, so complex in structure and function, is well developed +in all mammals, and its secreting tube, the bile-duct, always opens into +the duodenum, or that portion of the canal which immediately succeeds +the stomach. It is situated on the right side of the abdomen in contact +with the diaphragm and the stomach, but varies greatly in relative size, +and also in form, in different groups of mammals. In most mammals a +gall-bladder, consisting of a pyriform diverticulum from the bile-duct, +is present, but in many this appendage is wanting, and it is difficult to +find the rationale of its presence or absence in relation to use or any +other circumstance in the animal economy. + +The descriptions of the livers of various animals to be met with in +treatises or memoirs on comparative anatomy are very difficult to +understand for want of a uniform system of nomenclature. The difficulty +usually met with arises from the circumstance that this organ is divided +sometimes, as in Man, Ruminants, and the Cetacea, into two main lobes, +which have been always called respectively right and left, and in other +cases, as in the lower Monkeys, Carnivora, Insectivora, and several other +orders, into a larger number of lobes. Among the latter the primary +division usually appears at first sight tripartite, the whole organ +consisting of a middle, called “cystic” or “suspensory” lobe, and two +lateral lobes, called respectively right and left lobes. This introduces +confusion in describing livers by the same terms throughout the whole +series of mammals, since the right and left lobes of the Monkey or Dog, +for instance, do not correspond with parts designated by the same names +in Man and the Sheep. There are, moreover, conditions where neither the +bipartite nor the tripartite system of nomenclature will answer, so that +we should have considerable difficulty in describing them without some +more general system. In order to arrive at such a system it appears +desirable to consider the liver in all cases as primarily divided by the +umbilical vein (see Fig. 22, _u_) into two segments, right and left. This +corresponds with its development and with the condition characteristic +of the organ in the inferior classes of vertebrates. The situation of +this division can almost always be recognised in adult animals by the +persistence of some traces of the umbilical vein in the form of the round +ligament, and by the position of the suspensory ligament. + +[Illustration: FIG. 22.—Diagrammatic plan of the inferior surface of +a multilobed liver of a Mammal. The posterior or attached border is +uppermost. _u_, Umbilical vein of the fœtus, represented by the round +ligament in the adult, lying in the umbilical fissure; _dv_, the ductus +venosus; _vc_, the inferior vena cava; _p_, the vena portæ entering the +transverse fissure; _llf_, the left lateral fissure; _rlf_, the right +lateral fissure; _cf_, the cystic fissure; _ll_, the left lateral lobe; +_lc_, the left central lobe; _rc_, the right central lobe; _rl_, the +right lateral lobe; _s_, the Spigelian lobe; _c_, the caudate lobe; _g_, +the gall-bladder.] + +When the two main parts into which the liver is thus divided are entire, +as in Man, the Ruminants, and Cetacea, they may be spoken of as the +right and left lobes; when fissured, as the right and left segments +of the liver, reserving the term lobe for the subdivisions. This will +involve no ambiguity, for the terms right and left lobe will no longer +be used for divisions of the more complex form of liver. In the large +majority of mammals each segment is further divided by a fissure, more +or less deep, extending from the free towards the attached border, which +are called right and left lateral fissures (Fig. 22, _rlf_ and _llf_). +When these are more deeply cut than the umbilical fissure (_u_), the +organ has that tripartite or trefoil-like form just spoken of, but it +is easily seen that it is really divided into four regions or lobes, +those included between the lateral fissures being the right and left +central (_rc_ and _lc_) separated by the umbilical fissure, and those +beyond the lateral fissures on each side being the right and left lateral +lobes (_rl_ and _ll_). The essentially bipartite character of the organ +and its uniformity of construction throughout the class are thus not +lost sight of, even in the most complex forms. The left segment of the +liver is rarely complicated to any further extent, except in some cases +by minor or secondary fissures marking off small lobules, generally +inconstant and irregular, and never worthy of any special designation. +On the other hand, the right segment is usually more complex. The +gall-bladder, when present, is always attached to the under surface of +the right central lobe, sometimes merely applied to it, in other cases +deeply embedded in its substance. In many instances the fossa in which +it is sunk is continued to the free margin of the liver as an indent, or +even a tolerably deep fissure (_cf_). The portal fissure (_p_), through +which the portal vein and hepatic artery enter and the bile-duct emerges +from the liver, crosses the right central lobe transversely, near the +attached border of the liver. The right lateral lobe always has the +great vena cava (_vc_) either grooving its surface or tunnelling through +its substance near the inner or left end of its attached border; and a +prolongation of this lobe to the left, between the vein and the portal +fissure, sometimes forming a mere flat track of hepatic substance, but +more often a prominent tongue-shaped process, is the so-called “Spigelian +lobe” (_s_). From the under surface, of the right lateral lobe a portion +is generally partially detached by a fissure, and called the “caudate +lobe” (_c_). In Man this lobe is almost obsolete, but in most mammals it +is of considerable magnitude, and has very constant and characteristic +relations. It is connected by an isthmus at the left (narrowest or +attached) end to the Spigelian lobe, behind which isthmus the vena cava +is always in relation to it, channelling through or grooving its surface. +It generally has a pointed apex, and is deeply hollowed to receive the +right kidney, to the upper and inner side of which it is applied. + +Considerations derived from the comparatively small and simple condition +of the liver of the Ungulata, compared with its large size and complex +form in the Carnivora, have led to the perhaps too hasty generalisation +that the first type is related to a herbivorous and the latter to a +carnivorous diet. The exceptions to such a proposition are very numerous. +The fact of the great difference between the liver of the Cetacea and +that of the Seals cannot be accounted for by difference of habits of +life, though it perhaps may be by difference of origin.[14] + + +V. CIRCULATORY, ABSORBENT, RESPIRATORY, AND URINARY SYSTEMS. + +_Blood._—The blood of mammals is always red, and during the life of the +animal hot, having a nearly uniform temperature, varying within a few +degrees on each side of 100° Fahr. The corpuscles are, as usual in the +vertebrates, of two kinds: (1) colourless, spheroidal, nucleated, and +exhibiting amœboid movements; while (2) the more numerous, on which +depends the characteristic hue of the fluid in which they are suspended, +are coloured, non-nucleated, flattened, slightly biconcave discs, with +circular outline in all known species except the Camels and Llamas, +where they have the elliptical form characteristic of the red corpuscles +of nearly all the other vertebrates, though adhering to the mammalian +type in the absence of nucleus and relatively small size. As a rule they +are smaller as well as more numerous than in other classes, but vary +considerably in size in different species, and not always in relation +to the magnitude of the animal; a Mouse, for instance, having as large +corpuscles as a Horse. Within the limits of any natural group there is, +however, very often some such relation, the largest corpuscles being +found among the large species and the smallest corpuscles among the small +species of the group, but even to this generalisation there are many +exceptions. The transverse diameter of the red corpuscles in Man averages +¹⁄₃₂₀₀ of an inch, which is exceptionally large, and only exceeded by +the Elephant (¹⁄₂₇₄₅), and by some Cetacea and Edentata. They are also +generally large in Apes, Rodents, and the Monotremata, and small in the +Artiodactyles, least of all in the Chevrotains (_Tragulus_), being in _T. +javanicus_ and _meminna_ not more than ¹⁄₁₂₃₂₅.[15] + +_Heart._—The heart of mammals consists of four distinct cavities, +two auricles and two ventricles. Usually the ventricular portion is +externally of conical form, with a simple apex, but in the Sirenia it is +broad and flattened, and a deep notch separates the apical portion of +each ventricle. A tendency to this form is seen in the Cetacea and the +Seals. It is characteristic of mammals alone among vertebrates that the +right auriculo-ventricular valve is tendinous like the left, consisting +of flaps held in their place by fibrous ends (_chordæ tendiniæ_) and +arising from projections of the muscular walls of the ventricular cavity +(_musculi papillares_). In the Monotremata a transition between this +condition and the simple muscular flap of the Sauropsida is observed. In +most of the larger Ungulates a distinct but rather irregular ossification +(_os cordis_) is developed in the central tendinous portion of the base +of the heart. + +_Blood-vessels._—The orifices of the aorta and pulmonary artery are each +guarded by three semilunar valves. The aorta is single, and arches over +the left bronchial tube. After supplying the tissues of the heart itself +with blood by means of the coronary arteries, it gives off large vessels +(“carotid”) to the head and (“brachial”) to the anterior extremities. The +mode in which these vessels arise from the aorta varies much in different +mammals, and the study of their disposition affords some guide to +classification. In nearly all cases the right brachial and carotid have a +common origin (called the “innominate artery” in anthropotomy). The other +two vessels may come off from this, as is the rule in Ungulates, the +common trunk constituting the “anterior aorta” of veterinary anatomy; or +they may be detached in various degrees, both arising separately from the +aorta, as in Man, or the left carotid from the innominate and the left +brachial from the aorta, a very common arrangement; or the last two from +a common second or left innominate, as in some Bats and Insectivores. +The aorta, after giving off the intercostal arteries, passes through the +diaphragm into the abdomen, and, after supplying the viscera of that +cavity by means of the gastric, hepatic, splenic, mesenteric, renal, +and spermatic vessels, gives off in the lumbar region a large branch +(iliac) to each of the hinder extremities, which also supplies the +pelvic viscera, and is continued onwards in the middle line, greatly +diminished in size, along the under surface of the tail as the caudal +artery. In certain mammals, arterial plexuses, called _retia mirabilia_, +formed by the breaking up of the vessel into an immense number of small +trunks, which may run in a straight course parallel to one another +(as in the limbs of Sloths and Slow Lemurs), or form a closely packed +network, as in the intracranial plexuses of Ruminants, or a sponge-like +mass of convoluted vessels, as in the intercostals of Cetaceans, are +peculiarities of the vascular system the meaning of which is not in all +cases clearly understood. In the Cetacea they are obviously receptacles +for containing a large quantity of oxygenated blood available during the +prolonged immersion, with consequent absence of respiration, to which +these animals are subject. + +The vessels returning the blood to the heart from the head and upper +extremities usually unite, as in Man, to form the single _vena cava +superior_ or precaval vein, but in some Insectivores, Chiroptera, and +Rodents, in the Elephant, and all Marsupials and Monotremes, the two +superior caval veins enter the right auricle without uniting, as in +birds. In Seals and some other diving mammals there is a large venous +sinus or dilatation of the inferior vena cava immediately below the +diaphragm. In the Cetacea the purpose of this is supplied by the immense +abdominal venous plexuses. As a rule the veins of mammals are furnished +with valves, but these are said to be altogether wanting in the Cetacea, +and in the superior and inferior cava, subclavian and iliac veins, the +veins of the liver (both portal and hepatic), heart, lungs, kidneys, +brain, and spinal cord of other mammals. Many of the veins within the +cranium are included in spaces formed by the separation of the laminæ of +the dura mater, and do not admit of being dilated beyond a certain size; +these are termed sinuses. The portal circulation in mammals is limited +to the liver, the portal vein being formed by the superior and inferior +mesenteric, the splenic, the gastro-epiploic, and the pancreatic veins. +The kidney is supplied solely by arterial blood, and its veins empty +their contents only into the inferior cava. + +_Lymphatic Vessels._—The _absorbent_ or _lymphatic_ system of vessels is +very fully developed in the Mammalia. Its ramifications extend through +all the soft tissues of the body, and convey a colourless fluid called +lymph, containing nucleated corpuscles, and also, during the process of +digestion, the chyle, a milky fluid taken up by the lymphatics (here +called lacteals) of the small intestine, and pour them into the general +vascular system, where they mix with the venous blood. The lymphatic +vessels of the hinder extremities, as well as those from the intestinal +canal, unite in the abdomen to form the “thoracic duct,” the hinder +end or commencement of which has a dilatation called the _receptaculum +chyli_. This duct, which is of irregular size and sometimes double, often +dividing and uniting again in its course, or even becoming plexiform, +passes forwards close to the bodies of the thoracic vertebræ, and +empties itself, by an orifice guarded by a valve, into the great left +brachio-cephalic vein, having previously received the lymphatics from +the thorax and the left side of the head and left anterior extremity. +The lymphatics from the right side of the head and right anterior limb +usually enter by a small distinct trunk into the corresponding part +of the right brachio-cephalic vein. The duct, and also the principal +lymphatic vessels, are provided with valves. + +Lymphatic glands, rarely met with in the Sauropsida, are usually +present in mammals, both in the general and in the lacteal system; the +latter being called “mesenteric glands.” They are round or oval masses, +situated upon the course of the vessels, which break up in them and +assume a plexiform arrangement, and then reunite as they emerge. No +structures corresponding to the pulsating “lymphatic hearts” of the lower +vertebrates have been met with in mammals. + +_Ductless Glands._—Associated with the vascular and lymphatic systems +are certain bodies (the functions of which are not properly understood), +usually, on account of their general appearance, grouped together under +the name of “ductless glands.” The largest of these is the “spleen,” +which is single, and always placed in mammals in relation to the +fundus or left end of the stomach, to which it is attached by a fold +of peritoneum. It is dark-coloured and spongy in substance, and has a +depression or “hilus” on one side, into which the splenic artery, a +branch of the cœliac axis of the abdominal aorta, enters, and from which +the vein joining the portal system emerges. The spleen varies much in +size and form in different mammals, being relatively very small in the +Cetacea. It is sometimes almost spherical, but more often flattened, +oval, triangular, or elongated, and occasionally, as in Monotremes and +most Marsupials, triradiate. The “suprarenal bodies” or “adrenals” are +two in number, each situated either in contact with, or at a short +distance in front of the anterior extremity of the kidney. They are +abundantly supplied with nerves, and are much larger relatively in +early than in adult life. The “thyroid bodies,” of which there are +generally two, though in Man and some other species they are connected +by an isthmus passing across the middle line, are constant in mammals, +though only met with in a rudimentary condition, if at all, in other +vertebrates. They are situated in the neck, in contact with the sides of +the anterior extremity of the trachea. The “thymus” lies in the anterior +part of the thorax, between the sternum and the great vessels at the +base of the heart, and differs from the thyroid in being median and +single, and having a central cavity. It attains its greatest development +during the period in which the animal is nourished by its mother’s milk, +and then it diminishes, and generally disappears before full growth is +attained. + +_Nostrils._—Mammals breathe occasionally through the mouth, but usually, +and in many cases exclusively, through the nostrils or _nares_. Those are +apertures, always paired (except in the toothed Cetacea, where they unite +to form a single external opening), and situated at the fore part of the +face, generally at or beneath the end of the muzzle, a median prominence +above the mouth. This is sometimes elongated to form a proboscis, to +the extremity of which the nostrils are carried, and which attains its +maximum of development in the Elephant. In the Cetacea the nostrils +are situated at a considerable distance behind the anterior end of the +face, upon the highest part of the head, and are called “blowholes,” +from the peculiar mode of respiration of those animals. The nostrils +are kept open by means of cartilages surrounding their aperture, which +many animals have the power of moving so as to cause partial dilatation +or contraction. In diving animals, as Seals and Cetacea, they can be +completely closed at will so as to prevent the entrance of water when +beneath the surface. The passage to which the nostrils lead is in most +mammals filled by a more or less complex sieve-like apparatus, formed +of the convoluted turbinal bones and cartilages, over which a moist, +vascular, ciliated mucous membrane is spread, which intercepts particles +of dust, and also aids in warming the inspired air before it reaches the +lungs. In the Proboscidea, in which these functions are performed by the +walls of the long tubular proboscis, this apparatus is entirely wanting. + +_Trachea._—The narial passages have the organ of smell situated in +their upper part, and communicate posteriorly with the pharynx, and +through the glottis with the “trachea” or windpipe, a tube by which +the air is conveyed to and from the lungs. The permanent patency of +the trachea during the varied movements of the neck is provided for by +its walls being stiffened by a series of cartilaginous rings or hoops, +which in most mammals are incomplete behind. Having entered the thorax, +the trachea bifurcates into the two bronchi, one of which enters, and, +dividing dichotomously, ramifies through each lung. In some of the +Cetacea and Artiodactyla a third bronchus is given off from the lower +part of the trachea, above its bifurcation and enters the right lung. + +_Larynx._—The upper end of the trachea is modified into the organ of +voice or “larynx,” the air passing through which to and from the lungs +is made use of to set the edges of the “vocal cords,” or fibrous bands +stretched one on each side of the tube, into vibration. The larynx is +composed of several cartilages, such as the “thyroid,” the “cricoid,” +and the “arytenoid” which are moved upon one another by muscles, and +suspended from the hyoidean arch. By alteration of the relative position +of these cartilages the cords can be tightened or relaxed, approximated +or divaricated, as required to modulate the tone and volume of the voice. +A median tongue-shaped fibro-cartilage at the top of the larynx, the +“epiglottis,” protects the “glottis,” or aperture by which the larynx +communicates with the pharynx, from the entry of particles of food during +deglutition. The form of the larynx and development of the vocal cords +present many variations in different members of the class, the greatest +modification from the ordinary type being met with in the Cetacea, +where the arytenoid cartilages and epiglottis are united in a tubular +manner, so as to project into the nasal passage, and, being grasped by +the muscular posterior margin of the palate, provide a direct channel +of communication from the lungs to the external surface. An approach to +this condition is met with in the Hippopotamus and some other Ungulates; +it is indeed so general as an abnormality, that Howes suggests that +an internarial epiglottis may have been a primitive feature common +throughout the class. Nearly all mammals have a voice, although sometimes +it is only exercised at seasons of sexual excitement. Some Marsupials +and Edentates appear to be quite mute. In no mammal is there an inferior +larynx, or “syrinx,” as in birds. + +_Diaphragm._—The thoracic cavity of mammals differs from that of the +Sauropsida in being completely separated from the abdomen by a muscular +partition, the “diaphragm,” attached to the vertebral column, the ribs, +and the sternum. This is much arched, with the convexity towards the +thorax, so that when its fibres contract and it is flattened the cavity +of the thorax is increased, and when they are relaxed the cavity is +diminished. + +_Lungs._—The lungs are suspended freely in the thorax, one on each side +of the heart, being attached only by the root, which consists of the +bronchus or air-tube and pulmonary arteries and veins by which the blood +is passed backwards and forwards between the heart and the lungs. The +remaining part of the surface of each lung is covered by serous membrane, +the “pleura”; and whatever the state of distension or contraction of the +chest-wall, is accurately in contact with it. Inspiration is effected +by the contraction of the diaphragm and by the intercostal and other +muscles elevating or bringing forward the ribs, and thus throwing the +sternum farther away from the vertebral column. As the surface of the +lung must follow the chest-wall, the organ itself is expanded, and air +rushes in through the trachea to fill all the minute cells in which the +ultimate ramifications of the bronchi terminate. In ordinary expiration +very little muscular power is expended, the elasticity of the lungs and +surrounding parts being sufficient to cause a state of contraction and +thus drive out at least a portion of the air contained in the cells, +when the muscular stimulus is withdrawn. The lungs are sometimes simple +externally, as in the Sirenia (where they are greatly elongated) and the +Cetacea, but are more often divided by deep fissures into one or more +lobes. The right lung is usually larger and more subdivided than the +left. It often has a small distinct lobe behind, wanting on the left +side, and hence called _lobulus azygos_. + +_Air-sacs._—Most mammals have in connection with the air passages certain +diverticuli or pouches containing air, the use of which is not always +easy to divine. The numerous air sinuses situated between the outer and +inner tables of the bones of the head, represented in Man by the antrum +of Highmore and the frontal and sphenoidal sinuses, and attaining their +maximum of development in the Indian Elephant, are obviously for the +mechanical purpose of allowing expansion of the osseous surface without +increase of weight. They are connected with the nasal passages. The +Eustachian tubes pass from the back of the pharynx to the cavity of +the tympanum, into which and the mastoid cells they allow air to pass. +In the _Equidæ_ there are large post-pharyngeal air-sacs in connection +with them. The Dolphins have an exceedingly complicated system of +air-sacs in connection with the nasal passages just within the nostrils, +and the Tapirs, Rhinoceroses, and Horses have blind sacs in the same +situation. In the males of some Seals (_Cystophora_ and _Macrorhinus_) +large pouches, which the animal can inflate with air, and which are not +developed in the young animal or the female, arise from the upper part +of the nasal passages, and lie immediately under the skin of the face. +These appear analogous, although not in the same situation, to the gular +pouch of the male Bustard. The larynx frequently has membranous pouches +in connection with it, into which air passes. These may be lateral and +opening just above the vocal cords, when they constitute the _sacculi +laryngis_, found in a rudimentary state in Man, and attaining an enormous +development, so as to reach to the shoulders and axillæ, in some of the +Anthropoid Apes; or they may be median, opening in front either above or +below the thyroid and cricoid cartilages, as in the Howling and other +Monkeys, and also in the Whalebone Whales and Great Anteater. + +_Urinary Organs._—The kidneys of mammals are more compact and definite +in form than in other vertebrates, being usually more or less oval, +with an indent on the side turned towards the middle line, from and +into which the vessels and ducts pass. They are distinctly divided into +a cortical secretory portion, composed mainly of convoluted tubes, and +containing the so-called Malpighian bodies; and a medullary excreting +portion, formed of straight tubes converging towards a papilla, embraced +by the commencement of the ureter or duct of the organ. The kidneys of +some mammals, as most Monkeys, Carnivores, Rodents, etc., are simple, +with a single papilla into which all the renal tubuli enter. In others, +as Man, there are many pyramids of the medullary portion, each with its +papilla, opening into a division (calyx) of the upper end of the ureter. +Such kidneys, either in the embryonic condition only, or throughout +life, are lobulated on the surface. In some cases, as in Bears, Seals, +and especially the Cetacea, the lobulation is carried further, the whole +organ being composed of a mass of renules, loosely united by connective +tissue, and with separate ducts, which soon join to form the common +ureter. + +_Bladder._—In all mammals except the Monotremes the ureters terminate +by slit-like valvular openings in the urinary bladder. This receptacle +when filled discharges its contents through the single median urethra, +which in the male is almost invariably included in the penis, and in +the females of some species of Rodents, Insectivores, and Lemurs has a +similar relation to the clitoris. In the Monotremes, though the bladder +is present, the ureters do not enter into it, but join the urino-genital +canal some distance below it, with the orifice of the genital duct +intervening. + + +VI. NERVOUS SYSTEM AND ORGANS OF SENSE. + +_Brain._—The brain of mammals shows a higher condition of organisation +than that of other vertebrates. The cerebral hemispheres have a greater +preponderance compared with other parts, especially to the so-called +optic lobes, or corpora quadrigemina, which are completely concealed by +them. The commissural system of the hemispheres is much more complex, +both fornix and corpus callosum being present in some form; and when the +latter is rudimentary, as in Marsupials and Monotremes, its deficiency +is made up for by the great size of the anterior commissure. The lateral +lobes of the cerebellum, wanting in lower vertebrates, are well developed +and connected by a transverse commissure, the pons Varolii. The whole +brain, owing especially to the size of the cerebral hemispheres, is +considerably larger relatively to the bulk of the animal than in other +classes, but it must be recollected that the size of its brain depends +upon many circumstances besides the degree of intelligence which an +animal possesses, although this is certainly one. Man’s brain is many +times larger than that of all other known mammals of equal bulk, and +even three times as large as that of the most nearly allied Ape. Equal +bulk of body is here mentioned, because, in drawing any conclusions +from the size of the brain compared with that of the entire animal, it +is always necessary to take into consideration the fact that in every +natural group of closely allied animals the larger species have much +smaller brains relatively to their general size than the smaller species, +so that, in making any effective comparison among animals belonging to +different groups, species of the same size must be selected. It may be +true that the brain of a Mouse is, as compared with the size of its +body, larger than that of a Man, but, if it were possible to reduce an +animal having the general organisation of a Man to the size of a Mouse, +its brain would doubtless be very many times larger; and conversely, as +shown by the rapid diminution of the relative size of the brain in all +the large members of the Rodent order, a Mouse magnified to the size of +a Man would, if the general rule were observed, have a brain exceedingly +inferior in volume. Although the brain of the large species of Whales is, +as commonly stated, the smallest in proportion to the bulk of the animal +of any mammal, this does not invalidate the general proposition that +the Cetacea have very large brains compared with terrestrial mammals, +like the Ungulata, or even the aquatic Sirenia, as may be proved by +placing the brain of a Dolphin by the side of that of a Sheep, a Pig, or +a Manatee of equal general weight. It is only because the universally +observed difference between the slower ratio of increase of the brain +compared with that of the body becomes so enormous in these immense +creatures that they are accredited with small brains. + +The presence or absence of “sulci” or fissures on the surface of +the hemisphere, dividing it into “convolutions” or “gyri,” and thus +increasing the superficies of the cortical gray matter, as well as +allowing the pia mater with its nutrient blood-vessels to penetrate +into the cerebral substance, follow somewhat similar rules. The sulci +are related partly to the high or low condition of organisation of +the species, but also in a great degree to the size of the cerebral +hemispheres. In very small species of all groups, even the Primates, they +are absent, and in the largest species of groups so low in the scale as +the Marsupials and Edentates they are found. They reach their maximum of +development in the Cetacea. + +The accompanying woodcut (Fig. 23) shows the principal parts of a +mammalian brain, as seen from the superior, lateral, and inner surfaces. +The sylvian fissure (_sf_) is one of the most constant of the sulci found +in the hemispheres. + +[Illustration: FIG. 23.—Brain of the Genet (_Genetta tigrina_). A, From +above; B, from the right side; C, inner surface of right hemisphere; +_cc_, corpus callosum; _c.m.s_, calloso-marginal sulcus; _c_, notch +representing central sulcus of other forms; _d_, depression on superior +lateral gyrus of hemisphere; _hg_, hippocampal gyrus; _i_, inferior +lateral gyrus of hemisphere; _m_, middle lateral gyrus of do.; _s_, +superior lateral gyrus of do.; _os_, supraorbital sulcus of do.; _sf_, +sylvian fissure of do.; _ol_, olfactory lobes. The deeply convoluted part +behind the cerebral hemisphere is the cerebellum, below which lies the +medulla oblongata, or commencement of the spinal cord. (Mivart, _Proc. +Zool. Soc._ 1882, p. 516.)] + +The researches of Palæontologists, founded upon studies of casts of the +interior of the cranial cavity of extinct forms, have shown that, in +many natural groups of mammals, if not in all, the brain has increased +in size, and also in complexity of surface foldings, with the advance +of time,—indicating in this, as in so many other respects, a gradual +progress from a lower to a higher type of development. + +_Nerves._—The twelve pairs of cranial nerves generally recognised in +vertebrates are usually all found in mammals, though the olfactory nerves +are excessively rudimentary, if not altogether absent, in the Toothed +Whales. The spinal cord, or continuation of the central nervous axis, +lies in the canal formed by the neural arches of the vertebræ, and gives +off the compound double-rooted nerves of the trunk and the extremities, +corresponding in number to the vertebræ, through the interspaces between +which they pass out to their destination. The cord is somewhat enlarged +at the two points where it gives off the great nerves to the anterior and +the posterior extremities, which, from their interlacements soon after +their origin, are called respectively the brachial and lumbar plexuses. +The ganglionic or sympathetic portion of the nervous system is well +developed, and presents few modifications. + +_Sense of Touch._—The sense of touch is situated in the skin generally, +but is most acute in certain regions more or less specialised for the +purpose by the presence of tactile papillæ, such as portions of the face, +especially the lips and end of the snout, and the extremities of the +limbs when these are used for other purposes than mere progression, and +the under surface of the end of the tail in some Monkeys. The “vibrissæ” +or long stiff bristles situated on the face of many mammals are rendered +extremely sensitive to touch by the abundant supply of branches from +the fifth nerve to their basal papillæ. In Bats the extended wing +membranes, and probably also the large ears and the folds and prominences +of skin about the face of some species, are so sensitive as to receive +impressions even from the different degrees of resistance of the air, and +so enable the animals to avoid coming in contact with obstacles to their +nocturnal flight. + +_Taste and Smell._—The organs of the other special senses are confined +to the head. Taste is situated in the papillæ scattered on the dorsal +surface of the tongue. The organ of smell is present in all mammals +except the Toothed Whales. It consists of a ramification of the olfactory +nerves over a plicated, moist, mucous membrane, supported by folded +plates of bone, placed on each side of the septum nasi in the roof, or +often in a partially distinct upper chamber, of the nasal passage, so +arranged that, of the air passing into the lungs in inspiration, some +comes in contact with it, causing the perception of any odorous particles +with which it may be charged. Many mammals possess intense powers of +smelling certain odours which others are quite unable to appreciate, and +the influence which this sense exercises over the well-being of many +species is very great, especially in indicating the proximity of others +of the same kind, and giving warning of the approach of enemies. The +development and modification of the sense of smell is probably associated +with that of the odorous secretion of the cutaneous glands. + +_Sight._—The organ of sight is quite rudimentary, and even concealed +beneath the integument, in some burrowing Rodents and Insectivores, +and is most imperfectly developed in the _Platanista_, or Freshwater +Dolphin of the rivers of India. In all other mammals the eyeball has +the structure characteristic of the organ in the higher Vertebrata, +consisting of parts through which the rays of light are admitted, +regulated, and concentrated upon the sensitive expansion of the +optic nerve lining the posterior part of the ball. A portion of the +fibrovascular and highly pigmented layer, the choroid, which is +interposed between the retina and the outer sclerotic coat, is in many +mammals modified into a brilliantly-coloured light-reflecting surface, +the _tapetum lucidum_. There is never a pecten or marsupium like that +of the Sauropsida, nor is the sclerotic ever supported by a ring of +flattened ossicles, as is so frequently the case in the lower vertebrated +classes. The eyeball is moved in various directions by a series of +muscles—the four straight, two oblique, and, except in the higher +Primates, a posterior retractor muscle called choanoid. The superior +oblique muscle passes through a tendinous pulley fastened to the roof +of the orbit, which is a feature not found beyond the limits of the +mammalian class. The eye is protected by the lids, generally distinctly +separated into an upper and a lower movable flap, which, when closed, +meet over the front of the eye in a more or less nearly horizontal line: +but sometimes, as in the Sirenia, the lids are not distinct, and the +aperture is circular, closing to a point. In almost all mammals below the +Primates, except the Cetacea, a “nictitating membrane” or third eyelid is +placed at the inner corner of the eyeball, and works horizontally across +the front of the ball within the true lids. Its action is instantaneous, +being apparently for the purpose of cleaning the front of the transparent +cornea;—a function unnecessary in animals whose eyes are habitually +bathed in water, and which in Man and his nearest allies is performed +by winking the true eyelids. Except in Cetacea the surface of the eye +is kept moist by the secretion of the lachrymal gland, placed under the +upper lid at its outer side, and the lids are lubricated by the Harderian +and Meibornian glands, the former being situated at the inner side of the +orbit, and especially related to the nictitating membrane, the latter in +the lining membrane of the lids. + +_Hearing._—The organ of hearing is inclosed in a bony capsule (periotic) +situated in the side of the head, intercalated between the posterior +(occipital) and the penultimate (parietal) segment of the skull. It +has, in common with other vertebrates, three semicircular canals and +a vestibule, but the cochlea is more fully developed than in the +Sauropsida, and, except in the Monotremes, spirally convoluted. The +tympanic cavity is often dilated below, forming a smooth rounded +prominence on the base of the skull, the auditory bulla (Fig. 8). The +three principal ossicles, the “malleus,” “incus,” and “stapes,” are +always present, but variable in characters. In the Sirenia, Cetacea, and +Seals they are massive in form, being in the first-named order of larger +size than in any other mammals. In the Cetacea the malleus is ankylosed +to the tympanic; but in other mammals it is connected only with the +membrana tympani. The stapes in the lower orders—Edentates, Marsupials, +and Monotremes—has a great tendency to assume the columnar form of the +corresponding bone in Sauropsida, its two rami entirely or partially +coalescing.[16] The tympanic membrane (drum of the ear) forms the outer +wall of the cavity. In the fœtal state it is level with the external +surface of the skull, and remains so permanently in a few mammals as the +American Monkeys; but commonly, by the growth of the squamosal bone, it +becomes deeply buried at the bottom of a bony tube (_meatus auditorus +externus_), which is continued to the surface of the skin in a fibrous +or fibro-cartilaginous form. In Whales, owing to the thickness of the +subcutaneous adipose tissue, this meatus is of great length, and is also +extremely narrow. In most aquatic and burrowing animals it opens upon +the surface by a simple aperture, but in the large majority of the class +there is a projecting fold of skin, strengthened by fibro-cartilages, +called the pinna, auricle, or “external ear,” of very variable size and +shape, generally movably articulated on the skull, and provided with +muscles to vary its position; this pinna helping to collect and direct +the vibrations of sound into the meatus. + + +VII. REPRODUCTIVE ORGANS. + +_Testes._—In the male the testes retain nearly their primitive or +internal position throughout life in the Monotremata, Sirenia, Cetacea, +most Edentata, Hyracoidea, Proboscidea, and Seals, but, in other groups +they either periodically (as in Rodentia, Insectivora, and Chiroptera) +or permanently pass out of the abdominal cavity through the inguinal +canal, forming a projection beneath the skin of the perineum, or becoming +suspended in a distinct pouch of integument called the scrotum. All the +Marsupials have a pedunculated scrotum, the position of which differs +from that of other mammals, being in front of, instead of behind, the +preputial orifice. As regards the presence, absence, or comparative size +and number of the accessory generative glands—prostate, vesicular, and +Cowper’s glands, as they are called—there is much variation in different +groups of mammals. + +_Penis._—The penis is almost always completely developed, consisting of +two corpora cavernosa attached to the ischial bones, and of a median +corpus spongiosum enclosing the urethra, and forming the glans at +the distal portion of the organ. In Marsupials, Monotremes, and the +Sloths and Anteaters, the corpora cavernosa are not attached directly +to the ischia, and in the last-named the penis is otherwise of a very +rudimentary character, the corpus spongiosum not being present. In many +Marsupials the glans penis is bifurcated. In most Primates, Carnivora, +Rodentia, Insectivora, and Chiroptera, but in no other orders, an _os +penis_ is present. + +_Ovaries and Oviduct._—In the female, the ovaries permanently retain +their original abdominal position, or only descend a short distance +into the pelvis. They are of comparatively smaller size than in other +vertebrates, have a definite flattened oval form, and are enclosed in a +more or less firm “tunica albiginea.” The oviduct has a trumpet-like, and +usually fimbriated abdominal aperture, and is more or less differentiated +into three portions:—(1) a contracted upper part, called in Man and +the higher mammals the “Fallopian tube”; (2) an expanded part with +muscular walls, in which the ovum undergoes the changes by which it is +developed into the fœtus, called the “uterus”; (3) a canal, the “vagina,” +separated from the last by a valvular aperture, and terminating in the +urino-genital canal, or common urinal and genital passage, which in +higher mammals is so short as scarcely to be distinct from the vagina. +The complete distinction of the oviducts of the two sides throughout +their whole length, found in all lower vertebrates, only occurs in this +class in Monotremes; a prevailing mammalian characteristic being their +more or less perfect coalescence in the middle line to form a single +median canal. In the Marsupials this union only includes the lower part +of the vagina; but in most Placentals it extends to the whole vagina +and a certain portion of the uterus, which cavity is then described as +“bicornuate.” In the higher mammals, as in Man, and also in some of +the Edentates, the whole of the uterus is single, the contracted upper +portion of the oviducts or Fallopian tubes, as they are then called, +entering its upper lateral angles by small apertures. In certain lower +forms the urino-genital canal opens with the termination of the rectum +into a common cloaca, as in other vertebrates; but it is characteristic +of the majority of the class that the two orifices are more or less +distinct externally. + +_Mammary Glands._—Mammary glands secreting the milk by which the young +are nourished during the first portion of their existence after birth, +are present in both sexes in all mammals, though usually only functional +in the female. In the Monotremes alone their orifices are mere scattered +pores in the skin, but in all other forms they are situated upon the +end of conical elevations, called mammillæ, or teats, which, taken into +the mouth of the young animal, facilitate the process of sucking. These +are always placed in pairs upon some part of the ventral surface of the +body, but vary greatly in number and position in different groups. In the +Cetacea, where the prolonged action of sucking would be incompatible with +their subaqueous life, the ducts of the glands are dilated into large +reservoirs from which the contents are injected into the mouth of the +young animal by the action of a compressor muscle. + +_Secondary Sexual Characters._—Secondary sexual characters, or +modifications of structure peculiar to one sex, but not directly related +to the reproductive function, are very general in mammals. They almost +always consist of the acquisition or perfection of some character by +the male as it attains maturity, which is not found in the female or +the young in either sex. In a large number of cases these clearly +relate to the combats in which the males of many species engage for +the possession of the females during the breeding season; others are +apparently ornamental, and of many it is still difficult to apprehend +the meaning. Many suggestions on this subject will, however, be found in +the chapters devoted to it in Darwin’s work on _The Descent of Man and +Selection in Relation to Sex_, where most of the best-known instances are +collected. Superiority of size and strength in the male of many species +is a well-marked secondary sexual character related to the purpose +indicated above, being probably perpetuated by the survivors or victors +in combats transmitting to their descendants those qualities which gave +them advantages over others of their kind. To the same category belong +the great development of the canine teeth of the males of many species +which do not use these organs in procuring their food, as the Apes, +Swine, Musk and some other Deer, the tusk of the male Narwhal, the +antlers of Deer, which are present in most cases only in the males, and +the usual superiority in size and strength of the horns of the _Bovidæ_. +Other secondary sexual characters, the use of which is not so obvious, or +which may only relate to ornament, are the presence of masses or tufts +of long hair on different parts of the body, as the mane of the male +Lion and Bison, the beards of some Ruminants and Bats (as _Taphozous +melanopogon_), Monkeys, and of Man, and all the variations of coloration +in the sexes, in which, as a general rule, the adult male is darker and +more vividly coloured than the female. Here may also be mentioned the +presence or the greater development of odoriferous glands in the male, +as in the Musk Deer, and the remarkable perforated spur with its glands +and duct, so like the poison-tooth of the venomous serpents, found in the +males of both _Ornithorhynchus_ and _Echidna_, the use of which is at +present unknown. + +_Placenta._—The development of the mammalian ovum, and the changes which +the various tissues and organs of the body undergo in the process of +growth, are too intricate subjects to be explained without entering into +details incompatible with the limits of this work, especially as they +scarcely differ, excepting in their later stages, from those of other +vertebrates, upon which, owing to the greater facilities these present +for examination and study, the subject has been more fully worked out. +There are, however, some points which require notice, as peculiar to the +mammalian class, and as affording at least some hints upon the difficult +subject of the affinities and classification of the members of the group. + +The nourishment of the fœtus during intra-uterine life takes place +through the medium of certain structures, partly belonging to the fœtus +itself and partly belonging to the inner parietes of the uterus of the +parent. These in their complete form constitute the complex organ called +the “placenta,” serving as the medium of communication between the mother +and fœtus, and in which the physiological processes that are concerned +in the nutrition of the latter take place; but as we shall see, though +a placenta, in the usual acceptation of the term, is peculiar to the +mammalian class, it is not in all of its members that one is developed. +The structures to which we shall have especially to refer are the outer +tunic of the ovum, to which, however formed, the term “chorion” is +commonly applied, and two sac-like organs connected with the body-cavity +of the embryo, both formed from the splanchnic mesoblast, lined by a +layer of the hypoblast. These are the “umbilical vesicle” or “yolk-sac” +and the “allantois.” + +The umbilical vesicle is a thin membrane enclosing the yolk, which by +the doubling in of the ventral walls of the embryo becomes gradually +formed into a distinct sac external to the body, with a pedicle (the +omphalo-enteric duct) by which for a time a communication is maintained +between its cavity and the intestinal canal. In the walls of this sac +blood-vessels (omphalo-meseraic or vitelline) are developed in connection +with the vascular system of the embryo, through which, either by their +contact with the outer surface of the walls of the ovum, or by the +absorption through them of the contents of the yolk-sac, the nutrition +of the embryo in the lower vertebrates chiefly takes place. In mammals +the umbilical vesicle plays a comparatively subordinate part in the +nourishment of the fœtus, its function being generally superseded by the +allantois. + +The last-named sac commences at a very early period as a diverticulum +from the hinder end of the alimentary tract of the embryo. Its proximal +portion afterwards becomes the urinary bladder, the contracted part +between this and the cavity of the allantois proper constituting the +urachus, which passes out of the body of the fœtus at the umbilicus +together with the vitelline duct. The mesoblastic tissue of the walls of +the allantois soon becomes vascular; its arteries are supplied with fœtal +blood by the two hypogastric branches of the iliacs, or main divisions of +the abdominal aorta, and the blood is returned by venous trunks uniting +to form the single umbilical vein which runs to the under surface of the +liver, where, part of it joining the portal vein and part entering the +vena cava directly, it is brought to the heart. These are the vessels +which, with their surrounding membranes, constitute the umbilical +cord—the medium of communication between the fœtus and the placenta, when +that organ is fully developed. + +The egg membranes of the Monotremes present many points of agreement +with those of the ovum of the Marsupials,[17] and differ from those of +the Placental types. Thus Monotremes and Marsupials agree in having +a vitelline membrane, which appears between the young ovum and the +follicular epithelium, persisting in the one case until the time of +hatching, and in the other till a late uterine stage. There are also +several other common features fully described in Mr. Caldwell’s memoir, +but which cannot be detailed in this work. + +In the Marsupialia the observations made many years ago by Sir R. Owen +upon the development of the Kangaroo have been confirmed by those of Dr. +H. C. Chapman,[18] while Dr. Selenka,[19] and Professor H. F. Osborn[20] +have contributed important evidence as to the structure and relations +of the fœtal membranes of the Opossums and others. It thus appears that +up to the period of the very premature birth of these animals the outer +covering of the ovum, or false chorion, is free from persistent villi, +and not adherent to the epithelium of the uterine walls; for, although +fitting into the folds of the latter, it is perfectly and readily +separable in its entire extent from them. The umbilical vesicle or +yolk-sac is large, vascular, and adherent to a considerable portion of +the false chorion or subzonal membrane, while the allantois is relatively +small, and although the usual blood-vessels can be traced into it, it +does not appear to contract any connection with the false chorion, and, +therefore, much less with the walls of the uterus, of such a nature as +to constitute a placenta. In some forms, however, such as the Opossums, +the umbilical vesicle or yolk-sac develops temporary villi, which unite +with the subzonal membrane, or false chorion, to form a disc-like area +closely attached to the cells covering the utricular glands of the +uterine epithelium, and thus forming a so-called _yolk-sac placenta_. +The function of this organ is considered to be the transmission of +the secretions of the utricular glands to the embryo by means of the +umbilical vesicle; the function of the allantois being either respiratory +or the absorption of the fluid secreted in the uterine cavity by the +utricular glands. + +While in the uterus the nourishment of the fœtus seems, therefore, to be +derived from the umbilical vesicle, as in reptiles and birds, rather +than from the uterine walls by means of the allantoic vessels, as in +the higher mammals. The latter vessels, in fact, play even a much less +important part in the development of these animals, not only than in +the placental mammals, but even than in the Sauropsida, for they can +scarcely have the respiratory function assigned to them in that group: +pulmonary respiration and the lacteal secretion of the mother very early +superseding all other methods of providing the due supply, both of oxygen +and of food required for the development and growth of the young animal. +In this sense the Marsupials may be looked upon as the most typically +“mammalian” of the whole class. In no other group do the milk-secreting +glands play such an important part in providing for the continuity of the +race. + +In the third primary division of the Mammalia, the so-called Placentalia, +the umbilical vesicle generally does not quite unite with the chorion, +and disappears as development proceeds, so that no trace of it can be +seen in the membranes of an advanced embryo; but it may persist until the +end of the intra-uterine life as a distinct sac in the umbilical cord, or +lying between the allantois and amnion. The disappearance or persistence +of the umbilical vesicle does not, according to our present knowledge, +appear to be correlated with a higher or lower general grade of +development, as might be presupposed. It is stated to have been found in +Man even up to the end of intra-uterine life, and also in the Carnivora, +while in the Ungulata and Cetacea it disappears at an earlier age. In +many, if not all, of the Rodentia, Insectivora, and Chiroptera, it plays +a more important part, becoming adherent to a considerable part of the +inner surface of the chorion, to which it conveys blood-vessels, although +villi do not appear to be developed from the surface of this part, as +they are on the portion of the chorion supplied by the allantoic vessels. +These orders thus present to a certain extent a transitional condition +from the Marsupials, although essentially different, in possessing the +structures next to be described. + +The special characteristic of the whole of the placental mammals +constituting the majority of the class, is that the allantois and its +vessels become intimately blended with a smaller or greater part of the +parietes of the ovum, forming a structure on the outer surface of which +villi are developed, and which, penetrating into corresponding cavities +of the “decidua,” or soft, vascular, hypertrophied lining membrane of +the uterus, constitutes the placenta. This organ may be regarded, as Sir +William Turner says, both in its function and in the relative arrangement +of its constituent textures, as a specially modified secreting gland, the +ducts of which are represented by the extremities of the blood-vessels +of the fœtal system. The passage of material from the maternal to the +fœtal-system of vessels is not a simple percolation or diffusion through +their walls, but is occasioned by the action of a layer of cells derived +from the maternal or uterine structures, and interposed between the +blood-vessels of the maternal part of the placenta and those of the villi +covering the chorion, in which the embryonic vessels ramify. + +The numerous modifications in the details of the structure of this +organ relate to augmenting the absorbing capacity of the vessels of the +chorion, and are brought about either by increasing the complexity of the +fœtal villi and maternal crypts over a limited area, or by increasing the +area of the part of the chorion covered by the placental villi, or by +various combinations of the two methods. + +The first class of variations has given rise to a distinction into +two principal kinds of placenta: (1) simple or non-deciduate, and +(2) deciduate. In the former the fœtal villi are received into +corresponding depressions of the maternal surface, from which at the +period of parturition they are simply withdrawn. In the second, or more +complex form, the relation is more intimate, a layer of greater or +less thickness of the lining membrane of the uterus, called “decidua,” +becoming so intimately blended with the chorion as to form part of the +placenta proper, or that structure which is cast off as a solid body +at parturition. In other words, in the one case the line of separation +between the placenta and uterus at birth takes place at the junction of +the fœtal and maternal structures, in the other through the latter, so +that a portion of them, often of considerable thickness, and containing +highly organised structures, is cast off with the former. It was once +thought that the distinction between these two forms of placentation is +so important as to constitute a sufficiently valid basis for a primary +division of the placental mammals into two groups. It has, however, been +shown that the distinction is one rather of degree than of kind, as +intermediate conditions may exist, and it is probable that in different +primary groups the simpler, non-deciduate form may have become developed +independently into one or other of the more complex kinds. + +Apart from its intimate structure, the placenta may be met with of very +varied general form. It may consist of villi scattered more or less +regularly over the greater part of the surface of the chorion, the two +extremities or poles being usually more or less bare. This form is called +the “diffused placenta.” It is probably a primitive condition, from which +most of the others are derived, although its existence must presuppose +the absence of the umbilical vesicle as a constituent of the chorionic +wall. It is found at present in the Manis among Edentates, the Cetacea, +the Perissodactyle Ungulates, and the Camels, Pigs, and Chevrotains +among the Artiodactyles. Such placentæ are always non-deciduate. Recent +observations by Sir W. Turner on the placentation of the Dugong show that +the Sirenia present the peculiarity of having a zonary placenta, which +is either entirely or in great part non-deciduate, and is, therefore, +transitional between the diffused and the true zonary type. + +In the true Ruminants or Pecora, among the Artiodactyle Ungulates, +the villi are aggregated in masses called cotyledons, with bare +spaces between. Such a placentation is called “polycotyledonary.” In +another modification the villi are collected in a more or less broad +band encircling the chorion, leaving a very large portion of the two +poles bare, constituting the “zonary placenta,” characteristic of the +Carnivora, and also occurring in the Elephant, Hyrax, and Orycteropus. +The fact of the form of the placenta of these three last-named animals +agreeing together, and with that of the Carnivora, does not, however, +necessitate the ascription of zoological affinities, as the same ultimate +form may have been attained by different processes of development. + +In another form one pole only of the chorion is non-vascular, the +placenta assuming a dome or bell shape, as in the Lemurs and the +Sloths. The transition from this, by the gradual restriction of the +vascular area, is easy to the oval or discoidal form of placenta of +the Anteaters, Armadillos, and higher Primates. The discoidal placenta +of the Rodents, Insectivores, and Chiroptera, though showing so much +superficial resemblance to that of the last-named order as to have led +to the inclusion of all these forms in one primary group, is now known +to be developed in another manner, not by the concentration of villi +from a diffused to a limited area, but by retaining the area to which +it was originally restricted in consequence of the large surface of the +chorion occupied, as before mentioned, by the umbilical vesicle. To +compensate for the smallness of area, the complex or deciduate structure +has been developed. Among some Rodents there is evidence to show that the +discoidal placenta has been derived from a zonary one, of which distinct +vestiges have been detected in the Mouse. We may conclude that, although +the characters and arrangement of the fœtal structures may not have that +extreme importance which has been attributed to them by some zoologists, +they will form, especially when more completely understood, valuable aids +in the study of the natural affinities and evolution of the Mammalia.[21] + + + + +CHAPTER III + +ORIGIN AND CLASSIFICATION OF THE MAMMALIA + + +_Origin._—Although, as stated in the first chapter, the mammalian +class, as at present known either by existing or extinct forms, is +completely isolated from all other groups of the animal kingdom, yet it +is impossible to refrain from speculating as to its origin and nearest +affinities. In arranging the classes of vertebrates in a linear series +it is customary to place them in the following order—Pisces, Amphibia, +Reptilia, Aves, Mammalia,—an order which probably indicates the relative +degree of elevation to which the most highly developed members of each +class has attained. Such an arrangement appears to express the true +relationship of the first four classes to one another, but it is quite +clear that the Mammalia have no sort of affinity with the Aves. Writing +in 1879, Professor Huxley[22] came to the conclusion that, in looking +among vertebrates for the progenitors of the Mammalia, we must pass +over all known forms of birds and reptiles, and go straight down to the +Amphibia. In addition to the characters derived from the conformation of +the pelvis upon which the argument was primarily based, the following +reasons were given for this conclusion: “The Amphibia are the only +air-breathing Vertebrata which, like mammals, have a dicondylian skull. +It is only in them that the articular element of the mandibular arch +remains cartilaginous, while the quadrate ossification is small, and the +squamosal extends down over it to the osseous elements of the mandible, +thus affording an easy transition to the mammalian condition of those +parts. The pectoral arch [girdle] of the Monotremes is as much amphibian +as it is sauropsidian; the carpus and the tarsus of all Sauropsida, +except the Chelonia, are modified away from the Urodele type, while those +of the mammal are directly reducible to it. Finally, the fact that in +all Sauropsida it is a right aortic arch which is the main conduit of +arterial blood leaving the heart, while in mammals it is a left aortic +arch which performs this office, is a great stumbling-block in the way +of the derivation of the Mammalia from any of the Sauropsida. But, if +we suppose the earliest forms of both the Mammalia and the Sauropsida +to have had a common Amphibian origin, there is no difficulty in the +supposition that, from the first, it was a left aortic arch in the one +series, and the corresponding right aortic arch in the other, which +became the predominant feeder of the arterial system.” Subsequently +Professor E. D. Cope[23] in a suggestive paper called attention to the +remarkable resemblances to the Monotremes presented by the skeleton of +that group of early secondary reptiles which he then designated the +Theromorpha, but which may be included in the Anomodontia of Sir R. Owen, +and came to the conclusion that in that group we have the true ancestors +of the Mammalia. This conclusion was, however, disputed by Dr. Baur,[24] +who considered that the Anomodontia were too specialised to have been +the actual progenitors of the Mammalia, and that they should rather be +regarded as a divergent branch of the stem which had given origin to the +Mammalia. Since that date observations made on the structure of the South +African Anomodonts have shown such an intimate connection between that +group and the Labyrinthodont Amphibians, that there can be no hesitation +in regarding the one as the direct descendant of the other; and we may +probably regard the Mammalia as having originated from the same ancestral +stock at the time the Amphibian type was passing into the Reptilian. From +this point of view, some of the mammalian features found in the more +specialised Anomodonts may probably be regarded as having been acquired +during a parallel line of development. + +Both the Anomodontia and the Mammalia differ from the Amphibians in the +loss of the splint-like parasphenoid which underlies the basisphenoid +axis of the skull, and by the ossification of that axis; but while the +former have become monocondylic by the participation of the basioccipital +in the support of the cranium, the latter retain the Amphibian dicondylic +plan. The skull of the Anomodonts presents mammalian resemblances not +found in any other Reptiles, this being especially noticeable in the +region of the squamosal; and it is only in this group and mammals that +the temporal or zygomatic arch is a squamoso-maxillary one (see p. +37). The resemblance between the pectoral and pelvic girdles of the +Anomodonts and those of the Monotreme Mammals is noticed under the head +of the latter, where reference is also made to the similarity in the +structure of the humerus in the two groups. The pes of the Amphibia and +Anomodontia agree in having a distinct intermedium, tibiale, fibulare, +and centrale, whereas in other Reptiles these bones are not generally +distinct; in Mammals the intermedium, fibulare, and centrale are +distinct, and according to Cope’s interpretation there may be a distinct +tibiale. + +_Classification._—In the present condition of the world, mammals +have become so broken up into distinct groups by the extinction of +intermediate forms, that a systematic classification is perfectly +practicable. Most of the associations of species, which we call “orders,” +and even the “suborders” and “families,” are natural groups. In +isolating, defining, and naming them, we are really dealing with facts +of nature of a totally different order from the artificial and fanciful +divisions formed in the infancy of zoological science. + +When, however, we pass to the extinct world, all is changed. In many +cases the boundaries of our groups become enlarged until they touch those +of others. New forms are discovered which cannot be placed within any of +the existing divisions. As the horizon of our vision is thus expanded, +the principles upon which a scheme of classification is constructed must +be altogether changed. Our present divisions and terminology are no +longer sufficient for the purpose; and some other method will have to be +invented to show the complex relationships existing between different +animal forms when viewed as a whole. The present time, pre-eminently +distinguished by the rapidly changing and advancing knowledge of extinct +forms, is scarcely one in which this can be done with any satisfactory +result; so that all attempts to form a classification embracing even the +already known extinct species must be only of a provisional and temporary +nature. + +In systematic descriptions in books, in lists, and catalogues, and in +arranging collections, the objects dealt with must be placed in a single +linear series. But by no means whatever can such a series be made to +coincide with natural affinities. The artificial character of such an +arrangement, the constant violation of all true relationships, are the +more painfully evident the greater the knowledge of the real structure +and affinities. But the necessity is obvious; and all that can be done is +to make such an arrangement as little as possible discordant with facts. + +The following table contains a list of the orders, suborders, and +families of existing mammals as recognised by the authors, and placed +in the order in which they will be treated of in this work. The more +important of the groups containing only extinct forms are added in a +different type, being interpolated, as near as may be, among those that +appear to be their existing relatives. + +A few explanatory remarks upon the mutual relations of some of the +principal groups mentioned in the table may be useful here, but the +subject will be more fully developed in treating separately of each +division. + +One of the most certain and fundamental points in the classification +of the Mammalia is, that all the animals now composing the class can +be grouped primarily into three natural divisions, which, presenting +very marked differential characters, and having no existing, or yet +certainly demonstrated extinct, intermediate, or transitional forms, +may be considered as subclasses of equal value, taxonomically speaking, +though very different in the numbers and importance of the animals at +present composing them. These three groups are often called by the names +originally proposed for them by Blainville—(1) _Ornithodelphia_, (2) +_Didelphia_, (3) _Monodelphia_—the first being equivalent to the order +_Monotremata_, the second to the _Marsupialia_, and the third including +all the remaining members of the class. Although actual palæontological +proof is wanting, there is much reason to believe that each of these, as +now existing, are survivors of distinct branches to which the earliest +forms of mammals have successively given rise, and for which hypothetical +branches Professor Huxley has proposed the names of _Prototheria_, +_Metatheria_, and _Eutheria_, names which, being far less open to +objection than those of Blainville, are here used as equivalents of the +latter. + +The only known existing PROTOTHERIA, although agreeing in many important +characters, evidently represent two very divergent stocks, perhaps as +far removed as are the members of some of the accepted orders of the +Eutheria. It would, however, be merely encumbering zoological science +with new names to give them any other than the ordinarily known family +designations of _Ornithorhynchidæ_ and _Echidnidæ_. + +Similarly with regard to the METATHERIA, although the great diversity +in external form, in anatomical characters, and in mode of life of the +various animals of this section might lead to their division into groups +equivalent to the orders of the Eutheria, we do not think it advisable to +depart from the usual custom of treating them all as forming one order, +called Marsupialia, the limits of which are equivalent to those of the +subclass. The characters of the six families which compose the group are +extremely well marked and easily defined; and since they form a regular +gradation between two extreme types, they can be satisfactorily arranged +in a serial order. A marked distinction in the dentition enables us to +divide them into primary groups or suborders. + +The remaining mammals are included in the EUTHERIA, PLACENTALIA, or +MONODELPHIA. Their affinities with one another are so complex that +it is impossible to arrange them serially with any regard to natural +affinities. Indeed each order is now so isolated that it is almost +impossible to say what its affinities are; and none of the hitherto +proposed associations of the orders into larger groups stand the test +of critical investigation. All serial arrangements of the orders are +therefore perfectly arbitrary; and although it would be of very great +convenience for reference in books and museums if some general sequence, +such as that here proposed, were generally adopted, such a result can +scarcely be expected, since equally good reasons might be given for +almost any other combination of the various elements of which the series +is composed. In fact, we have already seen reason to depart in some +respects from that used in the “Encyclopædia.” + +The Edentata, Sirenia, and Cetacea stand apart from all the rest in the +fact that their dentition does not conform to the general heterodont, +diphyodont type to which that of all other Eutheria can be reduced, and +which is such a close bond of union between them. In all three orders, +however, some indications may be traced of relationship, however distant, +with the general type. + +With regard to the Edentata, reasons will be given for believing +that both the Sloths and Anteaters are nearly related, and that the +Armadillos, though much modified, belong to the same stock, but that the +Pangolins and the Aard-varks represent very isolated forms. + +There is no difficulty about the limits of the order Sirenia, comprising +aquatic, vegetable-eating animals, with complete absence of hind limbs, +and low cerebral organisation, represented in our present state of +knowledge only by two existing genera, _Halicore_ and _Manatus_, and a +few extinct forms, which, though approaching a more generalised mammalian +type, show no special characters allying them to any of the other orders. +The few facts as yet collected relating to the former history of the +Sirenia leave us as much in the dark as to the origin and affinities of +this peculiar group of animals as we were when we only knew the living +members. They lend no countenance to their association with the Cetacea; +and, on the other hand, their supposed affinity with the Ungulata +receives no very material support from them. + +Another equally well-marked and equally isolated, though far more +numerously represented and diversified order, is that of the Cetacea, +placed simply for convenience next to the Sirenia; with which, except in +their fish-like adaptation to aquatic life, they have little in common. +The old association of these orders in one group can only be maintained +either in ignorance of their structure or in an avowedly artificial +system. Among the existing members of the order, there are two very +distinct types, the toothed Whales or Odontoceti, and the Baleen Whales +or Mystacoceti, which present as many marked distinguishing structural +characters as are found between many other divisions of the Mammalia +usually reckoned as orders. Since the extinct Zeuglodonts, so far as +their characters are known, do not fall into either of these groups, but +are in some respects annectant forms, we have placed them provisionally, +at least, in a third group by themselves, named Archæoceti. There is +nothing known at present to connect the Cetacea with any other order of +Mammals; but it is quite as likely that they are offsets of a primitive +Ungulate as of a Carnivorous type, or perhaps of a still more generalised +mammalian stock. + +The remaining Eutherian mammals are clearly united by the characters +of their teeth, being all heterodont and diphyodont, with their dental +system reducible to a common formula. + +Although older views of the relationship of Ungulate mammals expressed +by the terms _Pachydermata_, _Ruminantia_, and so forth, still +linger in some corners of zoological literature, no single point in +zoological classification can be considered so firmly established as +the distinction between the Perissodactyle and Artiodactyle Ungulates; +both being in the existing fauna of the world perfectly natural and +distinctly circumscribed groups. The breaking-up of the latter into +four equivalent sections, the Pecora, Tylopoda, Tragulina, and Suina, +is equally in accordance with all known facts. Less certain, however, +is the association of the Proboscidea and the Hyracoidea with the true +Ungulates. By many zoologists they are each, although containing so very +few existing species, made into distinct orders; and much is to be said +in favour of this view. The discovery, however, of a vast number of +extinct species of Ungulates which cannot be brought under the definition +of either Perissodactyla or Artiodactyla, and yet are evidently allied +to both, and to a certain extent bridge over the interval between them +and the isolated groups just mentioned, make it necessary either to +introduce a number of new and ill-defined ordinal divisions, or so to +widen the scope of the original order as to embrace them all, considering +the Elephants and the Hyraces as representing suborders equivalent to +the great Perissodactyle and Artiodactyle groups. It is the latter +alternative that we have adopted. + +The Rodentia, although generally presenting a low grade of development, +are a very specialised and distinct group. The position here assigned to +them would accord with apparent relationships with the Ungulates, through +the Elephant on the one hand and the extinct _Typotherium_ on the other. + +In the present state of the fauna of the earth, the Carnivora form a +very distinct order, though naturally subdivided into two groups, the +members of the one being more typical, while those of the other (the +_Pinnipedia_) are aberrant, having the whole of their organisation +specially modified for living habitually in the water. + +The Insectivora comprise various lowly organised and generalised forms, +exhibiting considerable divergence of character, and apparently connected +through transitional extinct species with the Carnivora. As no other +order can claim the family _Galeopithecidæ_, it is placed here, but +rather for convenience than for any other consideration, since it has but +little if any relationship with any of the other members. Its isolated +position is indicated by assigning it a distinct subordinal rank. + +The Chiroptera have always been placed near the Insectivora; but they +are really a highly specialised group, as much isolated from all other +mammals by the modification of their anterior limbs in adaptation to +aerial locomotion, as the Cetacea and the Sirenia, by the absence of hind +limbs, are specially adapted for an aquatic life. + +Lastly, the Primates, which in any natural system must be placed at the +head of the series, are divisible into two very distinct groups—one +containing the various forms of Lemurs (Lemuroidea), and the other the +Monkeys and Man (Anthropoidea). Whether the Lemuroidea should form part +of the Primates (according to the traditional view), or a distinct order +altogether removed from it, is as yet an undetermined question, for both +sides of which there is much to be said. There can, however, be no doubt +that the Anthropoidea form a perfectly natural group, presenting a series +of tolerably regular gradations from the Marmosets (_Hapale_) to Man. +Certain breaks in the series, however, enable us to divide it into five +distinct families:—_Hapalidæ_ or Marmosets: _Cebidæ_ or American Monkeys, +with three premolar teeth on each side of each jaw; _Cercopithecidæ_, +containing the majority of Old-world Monkeys; _Simiidæ_, consisting of +the genera _Hylobates_, _Simia_, _Gorilla_, and _Anthropopithecus_, the +true Man-like Apes; and, lastly, _Hominidæ_, containing the genus _Homo_ +alone. + + Subclass I. PROTOTHERIA. + + Order i. MONOTREMATA—Monotremes. + + Fam. 1. _Ornithorhynchidæ_—Duck-bill. + 2. _Echidnidæ_—Spiny Anteater. + + Group. =MULTITUBERCULATA.=[25] + + Fam. 1. =Plagiaulacidæ=—Plagiaulax. + 2. =Polymastodontidæ=—Polymastodon. + 3. =Tritylodontidæ=—Tritylodon. + + Subclass II. METATHERIA. + + Order ii. MARSUPIALIA—Marsupials. + + Suborder 1. POLYPROTODONTIA—Polyprotodonts. + + Fam. 1. =Dromatheriidæ=—Dromatherium. + 2. =Amphitheriidæ=—Amphitherium, etc. + 3. =Spalacotheriidæ=—Spalacotherium. + 4. =Tritylodontidæ=—Tritylodon. + 5. _Didelphyidæ_—Opossums. + 6. _Dasyuridæ_—Thylacine and Dasyures. + 7. _Peramelidæ_—Bandicoots. + + Suborder 2. DIPROTODONTIA—Diprotodonts. + + Fam. 8. _Phascolomyidæ_—Wombats. + 9. _Phalangeridæ_—Phalangers. + 10. =Diprotodontidæ=—Diprotodon. + 11. =Nototheriidæ=—Notothere. + 12. _Macropodidæ_—Kangaroos. + + Subclass III. EUTHERIA. + + Order iii. EDENTATA—Edentates. + + Fam. 1. _Bradypodidæ_—Sloths. + 2. =Megatheriidæ=—Ground Sloths. + 3. _Myrmecophagidæ_—Anteaters. + 4. _Dasypodidæ_—Armadillos. + 5. =Glyptodontidæ=—Glyptodonts. + 6. _Manidæ_—Pangolins. + 7. _Orycteropodidæ_—Aard-varks. + + Order iv. SIRENIA—Sirenians. + + Fam. 1. _Manatidæ_—Manatees. + 2. =Rhytinidæ=—Rhytina. + 3. _Halicoridæ_—Dugongs. + 4. =Halitheriidæ=—Halithere. + + Order v. CETACEA—Cetaceans. + + Suborder 1. MYSTACOCETI—Baleen Whales. + + Fam. 1. _Balænidæ_—Greenland Whale, etc. + + Suborder 2. =ARCHÆOCETI.= + + Fam. 2. =Zeuglodontidæ=—Zeuglodonts. + + Suborder 3. ODONTOCETI—Toothed Whales. + + Fam. 3. _Physeteridæ_—Sperm Whale. + 4. _Platanistidæ_—Freshwater Dolphins. + 5. _Delphinidæ_—Dolphins, Porpoises, etc. + + Order vi. UNGULATA—Hoofed Mammals. + + Suborder 1. ARTIODACTYLA—Artiodactyles. + + Section A. SUINA—Pig-like Artiodactyles. + + Fam 1. _Hippopotamidæ_—Hippopotamus. + 2. _Suidæ_—Pigs and Peccaries. + + Annectant types. + + { 3. =Chœropotamidæ=—Chœropotamus. + { 4. =Anthracotheriidæ=—Anthracothere. + { 5. =Merycopotamidæ=—Merycopotamus. + { 6. =Cotylopidæ=—Oreodonts. + { 7. =Anoplotheriidæ=—Anoplothere. + { 8. =Dichodontidæ=—Dichodon. + + Section B. TRAGULINA—Chevrotains. + + 9. _Tragulidæ_—Chevrotains. + + Section C. TYLOPODA—Camels. + + 10. _Camelidæ_—Camels and Llamas. + 11. =Poebrotheriidæ=—Poëbrotherium. + + Section D. PECORA—True Ruminants. + + 12. _Cervidæ_—Deer. + 13. _Giraffidæ_—Giraffe. + 14. _Antilocapridæ_—Prong-buck. + 15. _Bovidæ_—Sheep, Cattle, etc. + + Suborder 2. PERISSODACTYLA—Perissodactyles. + + Fam. 16. _Tapiridæ_—Tapirs. + 17. =Lophiodontidæ=—Lophiodonts. + 18. =Palæotheriidæ=—Palæotheres. + 19. _Equidæ_—Horses. + 20. _Rhinocerotidæ_—Rhinoceroses. + 21. =Lambdotheriidæ=—Palæosyops. + 22. =Chalicotheriidæ=—Chalicothere. + 23. =Titanotheriidæ=—Titanothere. + 24. =Macraucheniidæ=—Macrauchenia. + + Suborder 3. =TOXODONTIA=—Toxodonts. + + Fam. 25. =Toxodontidæ=—Toxodon. + 26. =Typotheriidæ=—Typothere. + + Suborder 4. =CONDYLARTHRA.= + + Fam. 27. =Periptychidæ=—Periptychus. + 28. =Phenacodontidæ=—Phenacodus. + 29. =Meniscotheriidæ=—Meniscothere. + + Suborder 5. HYRACOIDEA—Hyraces. + + Fam. 30. _Hyracidæ_—Hyrax. + + Suborder 6. =AMBLYPODA.= + + Fam. 31. =Pantolambdidæ=—Pantolambda. + 32. =Coryphodontidæ=—Coryphodon. + 33. =Uintatheriidæ=—Uintathere. + + Suborder 7. PROBOSCIDEA—Proboscideans. + + Fam. 34. =Dinotheriidæ=—Dinothere. + 35. _Elephantidæ_—Elephants. + + Group. =TILLODONTIA=—Tillodonts. + + Fam. =Anchippodontidæ=—Anchippodus. + =Calamodontidæ=—Calamodon. + + Order vii. RODENTIA—Rodents. + + Suborder 1. SIMPLICIDENTATA. + + Fam. 1. _Anomaluridæ_—Anomalurus. + 2. _Sciuridæ_—Squirrels and Marmots. + 3. _Haplodontidæ_—Haplodon. + 4. =Ischyromyidæ=—Ischyromys. + 5. _Castoridæ_—Beavers. + 6. _Myoxidæ_—Dormice. + 7. _Lophiomyidæ_—Lophiomys. + 8. _Muridæ_—Rats, Mice, and Voles. + 9. _Spalacidæ_—Mole-rats. + 10. _Geomyidæ_—Pouched Rats. + 11. _Dipodidæ_—Jerboas. + 12. =Theridomyidæ=—Theridomys. + 13. _Octodontidæ_—Spiny Mice. + 14. =Castoroididæ=—Castoroides. + 15. _Hystricidæ_—Porcupines. + 16. _Chinchillidæ_—Chinchillas. + 17. _Dinomyidæ_—Dinomys. + 18. _Caviidæ_—Cavies. + 19. _Dasyproctidæ_—Agouties. + + Suborder 2. DUPLICIDENTATA. + + Fam. 20. _Lagomyidæ_—Picas. + 21. _Leporidæ_—Hares and Rabbits. + + Order viii. CARNIVORA—Carnivores. + + Suborder 1. CARNIVORA VERA—Fissipedes. + + Fam. 1. _Felidæ_—Cats. + 2. _Hyænidæ_—Hyænas. + 3. _Proteleidæ_—Earth-wolf. + 4. _Viverridæ_—Civets and Ichneumons. + 5. _Canidæ_—Wolves and Foxes. + 6. _Ursidæ_—Bears. + 7. _Mustelidæ_—Weasels and Otters. + 8. _Procyonidæ_—Raccoons and Cat-bear. + + Suborder 2. PINNIPEDIA—Pinnipedes. + + Fam. 9. _Otariidæ_—Eared Seals. + 10. _Trichechidæ_—Walrus. + 11. _Phocidæ_—Seals. + + Suborder 3. =CREODONTA=—Creodonts. + + Fam. 12. =Hyænodontidæ=—Hyænodon. + 13. =Proviverridæ=—Proviverra. + 14. =Arctocyonidæ=—Arctocyon. + 15. =Mesonychidæ=—Mesonyx. + + Order ix. INSECTIVORA—Insectivores. + + Suborder 1. INSECTIVORA VERA. + + Fam. 1. _Tupaiidæ_—Tupaias. + 2. _Macroscelididæ_—Elephant-Shrews. + 3. _Erinaceidæ_—Hedgehogs. + 4. _Soricidæ_—Shrews. + 5. _Talpidæ_—Moles. + 6. _Potamogalidæ_—Potamogale. + 7. _Solenodontidæ_—Solenodon. + 8. _Centetidæ_—Centetes. + 9. _Chrysochloridæ_—Golden Moles. + + Suborder 2. DERMOPTERA. + + Fam. 10. _Galeopithecidæ_—Galeopithecus. + + Order x. CHIROPTERA—Bats. + + Suborder 1. MEGACHIROPTERA—Frugivorous Bats. + + Fam. 1. _Pteropodidæ_—Flying Foxes. + + Suborder 2. MICROCHIROPTERA—Insectivorous Bats. + + Fam. 2. _Vespertilionidæ_—Common Bats. + 3. _Nycteridæ_—Nycteris. + 4. _Rhinolophidæ_—Leaf-nosed Bats. + 5. _Emballonuridæ_—Emballonura. + 6. _Phyllostomatidæ_—Vampyres. + + Order xi. PRIMATES. + + Suborder 1. LEMUROIDEA—Lemuroids. + + Fam. 1. =Hyopsodontidæ=—Hyopsodus. + 2. _Chiromyidæ_—Aye-Aye. + 3. _Tarsiidæ_—Tarsier. + 4. _Lemuridæ_—Lemurs. + + Suborder 2. ANTHROPOIDEA—Anthropoids. + + Fam. 5. _Hapalidæ_—Marmosets. + 6. _Cebidæ_—American Monkeys. + 7. _Cercopithecidæ_—Old World Monkeys. + 8. _Simiidæ_—Gibbons and Man-like Apes. + 9. _Hominidæ_—Man. + +The distinctive character of these subclasses and orders, with an account +of their subdivisions and the principal forms contained in each, will be +given in subsequent chapters. + + + + +CHAPTER IV + +GEOGRAPHICAL AND GEOLOGICAL DISTRIBUTION + + +I. GEOGRAPHICAL DISTRIBUTION.[26] + +In considering the present distribution of mammals over the globe, we +may, in the first place, direct our attention to terrestrial or land +types, reserving the consideration of aerial types, like the Bats, and +aquatic forms, as exemplified by the Cetaceans, Sirenians, and Seals, to +separate sections. + +Among terrestrial forms each species has a certain definite area of +distribution in space, which may be of very wide extent, or may be +confined to a restricted region. This distributional area is, however, +always connected, or continuous; that is to say, that although we may +have a single species inhabiting two continents, like the Lion in Asia +and Africa, or dwelling both on a continent and adjacent continental +islands, like the Javan Rhinoceros of India, Java, and Borneo, yet we +shall always find that such areas, if not still connected, show evident +signs of having been so connected in comparatively late geological +epochs; and we never find instances of the same species inhabiting +totally disconnected areas, such as India and South America. As examples +of mammals with a wide distribution we may mention the Lion and the +Leopard, which are now found throughout Africa, and also occur in India, +as well as in the intervening areas of Arabia and Persia. In the case of +the former species, palæontology further teaches us that its distribution +in the last geological epoch was even more extensive, since we have good +evidence to show that it formerly ranged over the greater part of Europe, +including the British Isles. The Jackal affords another well-known +instance of a species common to India and Africa. The American Puma, +again, may be cited as an example of a mammal having a very wide range +in latitude, since it is found from Patagonia in the south to Canada in +the north. As instances of wide range in the opposite direction we have +only to mention the Reindeer and the Elk or Moose, found in the northern +regions of both the Old and New Worlds, which are only separated from one +another by the narrow channel of Behring Strait. + +Of mammals with extremely restricted distributional areas, we may mention +many of the Insectivora, such as the Desman of the Pyrenees, and some of +the Madagascar types of this order, the Lemurs from the same island, some +of the species of Marmots, the remarkable bear-like _Æluropus_ of Eastern +Tibet, one species of Zebra, and other Ungulates from Africa. + +The distribution of a genus (except of course when the genus is +represented only by a single form) is very generally more extensive +than that of a species; and this may be markedly the case when there +are only some two or three species in a genus. In genera, moreover, we +meet with what is known as discontinuous distribution, that is, where +the distributional area of one or more species is totally separated from +that of others. The best instance of this occurs in the case of the +Tapirs, where we find one species inhabiting the Malayan Peninsula, and +no others anywhere in the world, with the exception of South America. +The explanation of such an apparently anomalous feature in distribution +is to be found in the past history of the globe, which shows us that +Tapirs once existed in China, Europe, and North America, and, therefore, +indicates that the existing isolated species are the sole survivors of a +group once spread over a large portion of the earth’s surface. In regard +to generic distribution it must, however, be mentioned that this depends +to a great extent on the limits which we are disposed to assign to genera +themselves. + +As the distributional area of a genus generally exceeds that of a +species, so that of a family, or group of genera, is larger than that of +a single genus; and similarly the distribution of an order, or assemblage +of families, usually occupies a larger area than that of a single family. +Thus, for instance, the genus _Thylacinus_, represented only by the +so-called Tasmanian Wolf or Thylacine, is now entirely restricted to +Tasmania; but the family _Dasyuridæ_, to which that genus belongs, ranges +all over Australia, while the order Marsupialia, which includes the +_Dasyuridæ_, is found both in Australia and America, and in past epochs +was probably spread over the entire globe. + +A remarkable feature in connection with the distribution of the +terrestrial Mammalia is the circumstance that, with the exception of +certain species introduced by human agency, and small forms which can +easily have been transported on floating timber or other similar means, +they are totally absent from what are known as oceanic islands—that is +islands arising from great depths in the ocean, mainly composed of coral +or volcanic rocks, and showing no signs of having ever been connected +with the existing continents, or the larger and so-called continental +islands. The obvious explanation of this feature is, that from their +total isolation these islands have never been able to receive a mammalian +fauna from the great continental areas on which mammalian life was +probably first developed. + +As an intermediate step between these islands which are practically void +of mammalian life and the continents which teem with such a variety of +forms, are certain larger islands and portions of continents containing +a mammalian fauna more or less markedly distinct from that of the +whole of the other regions of the globe. The best instance of this is +Australia, which, with the exception of one dog—the Dingo—and certain +_Muridæ_ and Bats, has no mammals except Monotremes and Marsupials. The +latter are, moreover, perfectly distinct from those of America, which, +if we exclude the islands in the neighbourhood of Australia, is the +only other region which now possesses any Marsupials at all. Here also +we have a ready and full explanation which accords with all the facts; +since it is evident that Australia has been isolated from the Asiatic +continent from some very remote geological epoch, at which period it is +probable that Monotremes and Marsupials were the dominant if not the sole +representatives of the Mammalia then existing. Consequently Australia has +never been able to receive an influx of the Eutherian orders, which have +probably swept away all the Marsupials except the small American Opossums +from the rest of the globe. Again, the large island of Madagascar, which +has a fauna of an African type, but still very markedly different from +that of the mainland, may be considered to have been connected with the +latter at a time when the Eutheria had become the dominant forms, but has +been separated for a sufficiently long period to have enabled a large +number of its species and genera to have become distinct from those of +the adjacent continent. Similarly, there is evidence to show that South +America was probably cut off for a considerable period from the northern +half of the American continent, in consequence of which its lowly +organised fauna of Edentates were enabled to attain such a remarkable +development in the later geological periods. + +In contrast to the mammalian fauna of islands of the preceding type is, +or rather was, that of the British Islands, which in the early historic +and prehistoric periods was identical with that of the Continent. This +leads to the inference that at a comparatively late epoch there was a +direct land communication between Britain and the Continent, which is +shown by geological evidence to have actually been the case. + +The above instances are sufficient to show what an important influence +the date of separation of islands from the adjacent continents has +had upon their existing mammalian fauna, and how largely the present +distribution of mammalian life is bound up with the past history of our +globe. We must, however, not omit to mention another very important +agency of past times which has likewise had great influence on the +present distribution of the various faunas of the northern hemisphere. +This is the so-called glacial epoch, which took place immediately before +the establishment of the present condition of things, and appears to have +been the cause of the extinction of many of the larger mammalian types +which formerly inhabited Europe, and whose retreat to the warmer regions +of the south was apparently cut off by the Mediterranean. + +_Zoological Regions._—Zoologists are now generally agreed in dividing +the land surfaces of the globe into a number of zoological regions or +provinces, characterised by a more or less distinctly marked general +_facies_ of their fauna as a whole. Some of these regions are much more +distinctly defined than the others; and in the majority of cases there is +a kind of neutral ground or No-man’s-land at the junction between any two +of these regions. It must also be remembered that in the Old World proper +as we go back in time we find a gradual assimilation in the mammalian +faunas of the different regions, indicating that originally there was one +large fauna of a generally similar type occupying the greater portion of +this area. Thus we find that Hippopotami, Giraffes, Kudus, Elands, and +other types of Antelopes now restricted to Africa, formerly extended to +Europe and India, while there is also evidence to show that the group +of large anthropoid Apes, now found only in Africa and the Bornean +region, were likewise spread over a large part of the south-western half +of the Old World. Moreover, while at the present day there is a marked +connection between the mammals of the northern regions of both the Old +and New Worlds, in the Tertiary period it appears that the fauna of the +whole of North America was much more nearly allied to that of the central +regions of the Old World than is now the case. Thus in the Tertiary rocks +of America we meet with remains of what we are accustomed to regard as +such essentially Old World genera as Horses and Rhinoceroses. On the +other hand there are no traces in America of the existence at any period +of Apes, Giraffes, Hippopotami, or Hyænas, while that continent has +yielded evidence of groups of Ungulates totally unrepresented in the +eastern hemisphere. + +The chief zoological regions of the globe, proposed by Mr. Sclater in +1857, and now recognised by the majority of authorities, are six in +number, and are named as follows. Firstly, the Palæarctic region, +embracing the whole of Europe, Persia, Northern Arabia, and all of Asia +northward of the line of the Himalaya proper, Japan, that part of Africa +lying northward of the Sahara Desert, and the oceanic islands of the +North Atlantic. Secondly, the Ethiopian region, which comprises all +Africa lying to the south of the Sahara, the southern part of Arabia, +Madagascar, and the Mascarene Islands. Thirdly, the Oriental or Indian +region, which is taken to include India south of the Himalaya, and to the +north-west as far as Beluchistan, the Malay peninsula, southern China, +Sumatra, Java, Borneo, and the Philippines. Fourthly, the Australasian +region, which is usually defined as being bounded to the north-west by +the deep sea channel lying between Borneo and Celebes known as Wallace’s +line, and is taken to include Celebes, Lumbok, New Guinea, Australia, +Tasmania, New Zealand, and the host of oceanic islands in the South +Pacific. Several writers, however, prefer to regard Celebes and some +of the adjacent islands as representing a transitional Austro-Malayan +region. Fifthly, the Nearctic region, comprising Greenland and North +America as far south as the north of Mexico. And sixthly, the Neotropical +region, which embraces the remaining portion of the American continent +and the West Indies. + +Various minor modifications of this scheme have been proposed. Thus some +writers are disposed to raise India to the rank of a distinct primary +region, while others propose the same for New Zealand. The Palæarctic and +Nearctic regions have a large number of common types, more especially +among the mammals, and Dr. A. Heilprin[27] has expressed his opinion that +they should be regarded as a single primary region under the name of the +Holarctic. The same writer would also separate the South Pacific Islands +as constituting a Polynesian region. + +Minor divisions or sub-regions have also been marked out, but it will +be unnecessary to indicate their limits in the present work. We may, +however, mention the Mediterranean sub-region of the Palæarctic, which +includes the peninsular portion of southern Europe, North Africa, Asia +Minor, Persia, Afghanistan, Beluchistan, and Northern Arabia, as a good +instance of the transition from one region to another, since its fauna +has a mingling of Palæarctic, Ethiopian, and Oriental types, the former +being, however, the predominant ones. + +Of the chief mammalian types characteristic of these various regions only +a brief sketch can be given in this work. + +_Palæarctic Region._—The Palæarctic region is of enormous extent, +and includes countries varying greatly in their flora, climate, and +elevation. Thus it embraces the Arctic plains of Siberia, the warm +regions of Italy, Southern France, and Northern Africa, the forest-clad +slopes of the outer Himalaya, and the lofty arid plains of Turkestan +and Tibet, scorched by a burning sun in summer and chilled by a still +more terrible cold in winter. Its extreme limits in the west are marked +by the Canaries and Azores, and in the east by distant Japan; and yet +throughout this vast expanse we find a great uniformity of life, as +exemplified by the large number of British genera which occur also in +Japan. The mammals which are on the whole the most characteristic of this +region are the Sheep and Goats, forming a section of the great family +of _Bovidæ_; nearly all the species of which are Palæarctic, although +we meet with one Goat (_Capra_) in the Nilgherries of Southern India, +and a Sheep (_Ovis_) in the Nearctic region. The Musk Ox (_Ovibos_) +is characteristic of the Palæarctic and Nearctic regions. At least +one species of Camel is characteristic of this region, and it is not +improbable that the second may also have originated in it. There are +a few characteristic types of Antelopes, such as the Alpine Chamois +(_Rupicapra_), the Saiga of Tartary, and the Chiru (_Pantholops_) of +Tibet, each of which is represented by only a single species: and we +miss the host of Antelopes so characteristic of the Ethiopian region. +Deer (_Cervus_) are abundant, although by no means confined to this +region; and the Musk Deer (_Moschus_), the sole representative of the +subfamily _Moschinæ_, is exclusively Palæarctic. Monkeys, as a rule, +are absent, although we meet with one species of _Macacus_ in Northern +Africa and at Gibraltar, and some other types on the southern border of +Tibet. The Moles (_Talpa_) are mainly Palæarctic, although one species +enters Northern India, while the Desmans (_Myogale_) of the Pyrenees +and Southern Russia are unknown beyond the limits of this region. The +Water-shrew (_Nectogale_) is likewise a peculiar eastern Palæarctic +type. Among the Rodents, the Picas or Tailless Hares (_Lagomys_) and +the Dormice (_Myoxus_) are essentially Palæarctic forms, only one +species of each being found beyond the limits of the region, and the one +extra-Palæarctic species of _Lagomys_ occurring in the cognate Nearctic +region. The Mice and Rats are represented by the typical genus _Mus_ and +other types, and Hares (_Lepus_) and one species of Squirrel (_Sciurus_) +are common. The Carnivora include two species of Bears (_Ursus_), Wolves +and Foxes (_Canis_), a Lynx and a few species of Cats (_Felis_), as well +as numerous weasels (_Mustela_), and some other types. + +_Ethiopian Region._—The Ethiopian region is of great interest to the +student of mammals, since it is inhabited by a number of forms remarkable +for their large size. A considerable portion of the area consists of +desert, especially in the north; but there is also a wide extent of +grassy plains (veltd), as well as vast tracts of equatorial forests of +great density. Perhaps the most striking feature in the Ethiopian fauna +is the number of Ungulates, both of the Artiodactyle and Perissodactyle +sections. In the former section we have the Giraffes (_Giraffa_) +represented by one species, which is the type of a family, and is +unknown elsewhere. Equally characteristic are the Hippopotami, which +likewise form the type of a family, while the Pigs are represented by +the Wart-hogs (_Phacochœrus_) and the River-hogs, forming an aberrant +group of the genus _Sus_. The Oxen (_Bos_) are represented by Buffaloes, +but there are no species of true Oxen or Bison. The Antelopes attain +an extraordinary development, the number of species being estimated at +from eighty to ninety, which are referred to a large number of genera, +although several of these are more or less ill-defined. Most of these +genera are peculiar to this region, but the Gazelles (_Gazella_) are also +found in the desert regions of other parts of the Old World, and _Oryx_ +ranges into Arabia and Persia. In contrast to this abundance of Antelopes +is the total absence of the Deer family, or _Cervidæ_, which are so +characteristic of the Palæarctic and Oriental regions. The Chevrotains +or _Tragulidæ_ are, however, represented by _Dorcatherium_.[28] In the +Perissodactyle section we may notice the presence of two species of +_Rhinoceros_, both furnished with two horns, and distinguished from +those of the Oriental region by the absence of incisor and canine teeth. +The Horse family (_Equidæ_) is also represented by several species, and +includes the peculiar group of Zebras, characterised by their beautifully +striped skins. Of other Ungulates the Elephants, which, like the +Rhinoceroses, are now peculiar to the Ethiopian and Oriental regions, +have one species, which is widely different from its Indian congener. +The Hyraces are mainly characteristic of this region, although one +species occurs in Syria and Palestine. The Carnivora include some forms +like the Lion, Leopard, and Jackal, common to the Oriental region, but +likewise include certain peculiar types like the Earth-wolf (_Proteles_), +which may be regarded as the type of a distinct family, and two species +Hyænas, which are referred by some authorities to a distinct genus +(_Crocuta_). There is also the Hunting dog (_Lycaon_), and the peculiar +group of Foxes known as the Fennecs, together with _Otocyon_. Bears, +Wolves, and true Foxes are absent; but Civets, etc., are abundant, +although not characteristic of the region. The Primates yield several +very characteristic types, such as the Gorilla and the Chimpanzee +(_Anthropopithecus_) among the _Simiidæ_, which, with the exception of +the Orangs of Borneo, are the only existing large man-like Apes, and the +group of Dog-faced Baboons (_Cynocephalus_) in the _Cercopithecidæ_. +The genus _Colobus_ is also a group of the latter family, absolutely +characteristic of the region. Lemurs, again, occur on the continent of +Africa, but the great development of this group is in the adjacent island +of Madagascar, where several peculiar genera occur, and where the larger +Carnivora and Ungulata are absent. These peculiarities of the fauna of +Madagascar apparently point, as previously mentioned, to its separation +from the mainland before the latter was overrun by the larger types, and +at a time when its chief mammals were Lemurs and Insectivores. There +are two genera of Edentates, the Pangolins (_Manis_), and the Aard-vark +(_Orycteropus_), the latter being peculiar. + +Although the foregoing groups of mammals are now so characteristic of +the Ethiopian region, it cannot be too strongly insisted that their +restriction to this region is, so to speak, merely a feature of the +present day, and that at a late geological epoch nearly all the peculiar +genera were represented in India, and many of them also in Europe. + +_Oriental Region._—The third or Oriental region is likewise of very +considerable extent, and is the only one, in addition to the Ethiopian, +which is the home of huge Ungulates, like Elephants and Rhinoceroses, +and the large man-like Apes. A large proportion of this extensive area +is occupied by tropical and subtropical forests and swamps; these being +especially abundant in Burma, Southern China, Siam, and the southern +ridges of the Himalaya, collectively constituting the Indo-Chinese +sub-region, and also in the Indo-Malayan sub-region of the Malay +peninsula and adjacent islands. In the third or Indian sub-region, +comprising peninsular India, with the exception of the Carnatic, there +are large tracts of open country, including some of the hottest regions +in the world, parts of which form plains more or less covered with +vegetation during the cooler and rainy seasons, while others are barren +rocky table-lands, as in the Deccan, or arid deserts like those of parts +of the Punjab and Sind. Finally, in the fourth or Cingalese sub-region, +represented by the Carnatic and the island of Ceylon, we find vast areas +of luxuriant forest and jungle. In the north-western desert area of +the Indian sub-region the fauna includes a mixture of Palæarctic and +Ethiopian forms, with those characteristic of the Oriental region. + +Among the chief features of the mammalian fauna of this region we may +notice the absence of Hippopotami and Giraffes, the greatly diminished +number of Antelopes, as compared with those of Africa, and the abundance +of Deer and true Pigs. The Antelopes comprise the two peculiar genera +_Boselaphus_ (Nilghai) and the typical _Antilope_ (Black-buck), each +of which is represented by only a single species, while the Deer +belong to the so-called Rusine group, which is markedly different +from that to which the Palæarctic Red Deer belongs. True Chevrotains +(_Tragulus_) are peculiar to this region. The Oxen include the true +Buffalo, differing in many respects from the African species of the +same group, and also certain species of true Oxen, such as the Gaour +and Banting, belonging to the Bibovine group, which is confined to this +region. In the Perissodactyla Horses (_Equus_) are represented only +by a single species in the desert area of the Indian sub-region, while +the two species of _Rhinoceros_ differ from those of Africa in being +furnished with canines and incisors. The Malayan Tapir is the only Old +World species of its genus. The Indian Elephant differs, moreover, so +markedly from its African ally that some writers regard the two as types +of distinct genera. The Carnivora include the Lion, Leopard, Jackal, +and Hunting-Leopard, which are common to Africa; but the Tiger is very +characteristic of this region, although extending northwards into the +Palæarctic. Civets are abundant, comprising some peculiar genera, of +which it will suffice to mention the well known _Paradoxurus_. Wolves +closely allied to the Palæarctic species occur in Northern India, and +there are also Foxes related to the typical species. The Dog-like animals +which hunt in packs, and are separated by some writers from _Canis_ under +the name of _Cyon_, occur in the present and the Palæarctic region. +The striped Hyæna is the Indian representative of its genus. Ratels +are common to this and the Ethiopian region, and constitute the genus +_Mellivora_. The most striking feature in the Carnivorous fauna of this +region, as distinguished from the Ethiopian, is, however, the presence +of Bears, some of which belong to the typical genus _Ursus_, while one +species is usually generically separated under the name of _Melursus_. +Among the Rodents we may especially notice the abundance of the _Muridæ_ +and _Sciuridæ_. In the former family we have numbers of true Mice +(_Mus_), and also the peculiar genus _Nesocia_ (Bandicoot-Rat), while in +the latter both the true Squirrels (_Sciurus_) and the Flying-Squirrels +(_Pteromys_) attain great development. The genus (_Pteromys_) is, indeed, +mainly characteristic of this region, although in Kashmir and Japan it +enters the Palæarctic. The Bats are very numerous, being represented +by all the families, with the exception of the _Phyllostomatidæ_, or +Vampyres, of South America. Among the Insectivora the genera _Tupaia_ and +_Galeopithecus_ (Flying Lemur) are peculiar to this region, although not +found in India. Finally, in the Primates we have the genera _Macacus_ +and _Semnopithecus_ very abundantly represented, although both also +enter the Palæarctic region; but the Anthropoid types are confined to +the south-eastern half of the region, and include the Orangs (_Simia_) +of Borneo, and the smaller long-armed Gibbons (_Hylobates_), which are +abundant in the Malay peninsula, both genera not being found beyond this +region. The Lemurs are much less abundant than in the Ethiopian region, +but they include the peculiar Tarsier of Sumatra, Borneo, and Celebes +(Austro-Malayan region), which differs so markedly in dentition and +structure of the feet from all other forms that it has been made the type +of a separate family. The Edentates, so poorly represented in the Old +World, include only Pangolins (_Manis_), which, as we have already seen, +also occur in the Ethiopian region. + +_Australasian Region._—With the fourth or Australasian region we come +to a mammalian fauna so peculiar that we have no difficulty whatever +in defining it from all the other regions of the globe, although it +should be observed that in the Austro-Malayan islands we have a partial +mingling of the Australasian and Malayan faunas. If we exclude Celebes +from this region we find that, with the exception of a Pig in New Guinea, +of the Dingo in Australia, of numerous Mice and Rats (_Muridæ_), and +Bats, there are no Eutherian mammals throughout the area. The mammals +of this region are restricted to the Australian mainland, the island of +Tasmania, New Guinea, and the Aru islands, the whole area of New Zealand +having been totally devoid of mammalian life until introduced by man. +The whole of the Monotremata, constituting the subclass Prototheria, and +all the Marsupials, exclusive of the few outlying forms ranging into the +transitional Austro-Malayan area, and with the exception of the American +family of the Opossums (_Didelphyidæ_), are absolutely confined to this +region. + +_Celebes._—The mammals of Celebes—the typical representative of the +Austro-Malayan transitional region or sub-region—include the peculiar Ape +known as _Cynopithecus_, _Tarsius_ (also Oriental), the Anoa, and the +single species of _Babirusa_. Several other types of placental mammals +are found in this transitional area, while the Marsupials are represented +by _Phalanger_ and _Petaurus_. + +_Nearctic Region._—The two remaining regions we have to consider are +comprised in the New World. The first of these is the Nearctic, which, +as already mentioned, has a fauna showing such a strongly marked +relationship to that of the Palæarctic region, that it has been proposed +to unite the two regions. Among types common to these two regions we may +mention closely allied species of true Deer (_Cervus_) as exemplified +by the Red Deer and the Wapiti; the allied Bisons of the two regions; +the Reindeer and Elk common to both; as well as nearly related, and in +some cases identical, species of Cats, Lynxes, Bears, Wolves, Foxes, +Beavers, Squirrels, Marmots, and Hares. The Glutton or Wolverene, and +the Musk Ox is also common to the Arctic portions of the two regions. +The Ungulates are very poorly represented, but we have, in addition to +the forms already mentioned, one species of the Palæarctic genus _Ovis_, +namely the Bighorn, and the Prong-buck (_Antilocapra_), which is quite +peculiar. There are, however, no Perissodactyla. The Raccoons and Coatis +(_Procyonidæ_) constitute a family represented out of the New World +only by the aberrant Cat-Bear (_Ælurus_) of Nipal. The characteristic +American feline known as the Puma extends over this region; but there +are no Edentates, and the Marsupials are represented only by a single +species of Opossum. Rodents are extremely numerous, and comprise several +characteristic types, which alone would tell us what part of the globe we +were visiting. The most distinctive are the Pouched Rats (_Geomyidæ_), +and the Beaver-like rodents known as the _Haplodontidæ_. True Rats +and Mice (_Mus_), which are represented throughout the Old World, are +totally wanting in the New, where they are replaced by the Vesper-mice, +which may be included in the European genus _Cricetus_, although often +separated as _Hesperomys_. This feature alone would seem to justify the +distinction of the Nearctic from the Palæarctic region. The Musquash +(_Fiber_) is a genus of Nearctic rodents unknown in the Old World. Among +other characteristic genera we may mention, in the Carnivora, the Skunk +(_Mephitis_) and the American Badger (_Taxidea_). Primates are absent +from the entire region. + +_Neotropical Region._—The last of the six main regions is the +Neotropical, including Mexico, South America, and the West Indies. +A very large extent of this area is occupied by forests, which are +described as being denser and more luxuriant than those of any other +part of the globe. Alternating with these forest areas are the vast +grassy plains known in different regions as llanos, savannas, and +pampas. The back-bone of the region is formed by the great chain of +the Andes. Next to the Australasian, this region is perhaps better +characterised by its mammalian fauna than any of the others. Commencing +with the Ungulates, we find a total absence of Antelopes, Sheep, and +Oxen, and also of all Perissodactyles except Tapirs. Deer are, however, +represented, although by peculiar forms (_Cariacus_) unknown beyond +the New World. The Peccaries (_Dicotyles_), which are often made the +type of a distinct family, take the place of the Old World Pigs, +while the Llamas and Alpacas (_Auchenia_) are the substitutes for the +Palæarctic Camels. The Carnivora include several Cats (_Felis_), among +which the Puma and the Jaguar are the most noticeable; and there are +also Raccoons, Coatis, Foxes, and one species of Bear. Insectivora are +totally wanting; but the Bats are characterised by the presence of +the Vampyres (_Phyllostomatidæ_), which are almost restricted to this +region. The Rodents likewise include three families unknown elsewhere, +namely the Chinchillas and Viscacha (_Chinchillidæ_), the Agouties +(_Dasyproctidæ_), and the Cavies (_Caviidæ_); while a large number of the +_Octodontidæ_ are Neotropical, all the other forms being Ethiopian. In +the Primates, again, we have all the forms quite peculiar to this region, +and constituting two families, viz. the _Cebidæ_ or Prehensile-tailed +Monkeys, and the _Hapalidæ_, or Marmosets, both of which differ decidedly +in their dentition, as well as in other features, from the Old World +Monkeys. Lemuroids are unknown. Perhaps, however, the mammals which may +be considered as most characteristic of the Nearctic region are the +numerous Edentates, which form three families, mostly confined to it. +These comprise the _Bradypodidæ_ or Sloths, which solely inhabit the +forest region; the _Myrmecophagidæ_ or Anteaters; and the _Dasypodidæ_ +or Armadillos, of which one species has crept northward as far as Texas. +Almost equally characteristic are the numerous Opossums, the majority of +which belong to the genus _Didelphys_. Finally, it should be observed +that the West Indies are distinguished from the rest of the region by the +absence of Primates, Carnivora, and Edentates. + +_Aquatic Mammals._—Many mammals grouped for the present purpose as +terrestrial pass a great portion of their lives in brooks, lakes, or +rivers, and, being dependent upon such waters for obtaining their +subsistence, are necessarily confined to their vicinity; but the truly +aquatic mammals, or those living constantly in the water, and unable to +move their quarters from place to place by land, are the orders Cetacea +and Sirenia, with which may also be grouped the Seals, forming the +Pinniped division of the order Carnivora. + +For the marine Cetacea, animals mostly of large size and endowed with +powers of rapid locomotion, there are obviously no barriers to universal +distribution over the surface of the earth covered by sea, except such as +are interposed by uncongenial temperature or absence of suitable food. +Nevertheless it was thought some years ago that the fact of a Whale or +a Dolphin occurring in a sea distant from that in which it had usually +been found was sufficient justification for considering it as a distinct +species and imposing a new name upon it. There are now, however, so many +cases known in which Cetaceans from the northern and southern seas, from +the Atlantic and Pacific Oceans, present absolutely no distinguishing +external or anatomical characters upon which specific determination +can be based that the opposite view is gaining ground; and, since some +species are undoubtedly very widely distributed, being in fact almost +cosmopolitan, there seems little reason why many others should not be +included in the same category. The evidence is satisfactory enough in +those instances in which the intermediate regions are inhabited by the +same forms;—the cases of “continuous areas” of distribution. In those in +which the areas of distribution are apparently discontinuous, there may +be more room for doubt; but it must not be forgotten that the negative +evidence is here of much less value than in the case of land animals, +since the existence of Cetaceans in any particular part of the ocean may +be easily overlooked. The great Sperm Whale (_Physeter macrocephalus_) +is known to be almost cosmopolitan, inhabiting or passing through all +the tropical and temperate seas, although not found near either pole. +At least three of the well-known species of Rorqual (_Balænoptera_) of +the British coasts are represented in the North Pacific, on the South +American shores, and near New Zealand, by species so closely allied that +it is difficult to point out any valid distinctive characters, though +it may perhaps be desirable to wait for a more exhaustive examination +of a large series of individuals before absolutely pronouncing them to +be specifically identical. There is nothing yet known by which we can +separate the “Humpback Whales” (_Megaptera_) of Greenland, the Cape of +Good Hope, and Japan. The same may be said of the common Dolphin of +the European seas (_Delphinus delphis_) and the so-called _D. bairdi_ +of the North Pacific and _D. forsteri_ of the Australian seas. The +Pilot Whale (_Globicephalus melas_) and the _Pseudorca_ of the North +Atlantic and of New Zealand are also, so far as present knowledge +enables us to judge, respectively alike. Many other similar cases might +be given. Captain Maury collected much valuable evidence about the +distribution of the larger Cetacea, and, finding Right Whales (_Balæna_) +common in both northern and southern temperate seas, and absent in the +intermediate region, laid down the axiom that “the torrid zone is to +the Right Whale as a sea of fire, through which he cannot pass.” Hence +all cetologists have assumed that the Right Whale of the North Atlantic +(_B. biscayensis_), that of the South Seas (_B. australis_), and that +of the North Pacific (_B. japonica_), are necessarily distinct species. +The anatomical structure and external appearance of all are, however, so +far as yet known, marvellously alike, and, unless some distinguishing +characters can be pointed out, it seems scarcely justifiable to separate +them from geographical position alone; as, though the tropical seas +may be usually avoided by them, it does not seem impossible, or even +improbable, that some individuals of animals of such size and rapid +powers of swimming may have at some time traversed so small a space of +ocean as that which divides the present habitual localities of these +supposed distinct species. If identity or diversity of structural +characters is not to be allowed as a test of species in these cases, as +it is usually admitted to be in others, the study of their geographical +distribution becomes an impossibility. + +Although many species are thus apparently of such wide distribution, +others are certainly restricted; thus the Arctic Right Whale (_Balæna +mysticetus_) has been conclusively shown to be limited in its range to +the region of the northern circumpolar ice, and no corresponding species +has been met with in the southern hemisphere. In this case, not only +temperature, but also the peculiarity of its mode of feeding, may be +the cause. The Narwhal and the Beluga have a very similar distribution, +though the latter occasionally ranges farther south. The common +Hyperoödon is restricted to the North Atlantic, never entering, so far as +is yet known, the tropical seas. Other species are exclusively tropical +or austral in their range. One of the true Whalebone Whales (_Neobalæna +marginata_) has only been met with hitherto in the seas round Australia +and New Zealand; and a large Ziphioid (_Berardius arnouxi_) only near the +last-named islands. + +The Cetacea are not limited to the ocean, or even to salt water, some +entering large rivers for considerable distances, and others being +exclusively fluviatile. One species of _Platanista_ is extensively +distributed throughout nearly the whole of the river systems of the +Ganges, Brahmaputra, and Indus, ascending as high as there is water +enough to swim in, but apparently never passing out to sea. The +individuals inhabiting the Indus and the Ganges must therefore have been +for long ages isolated without developing any definite distinguishing +anatomical characters; for those by which the supposed _P. indi_ was +formerly separated from _P. gangetica_ have been shown by Anderson to be +of no constant value. _Orcella fluminalis_ appears to be limited to the +Irawaddy river, and at least two distinct species of Dolphin belonging +to different genera are found in the waters of the upper Amazon. A +_Neomeris_ has been found in the great Chinese river, the Yang-tsi-Kiang, +nearly a thousand miles from the sea. It is remarkable, however, that +none of the great lakes or inland seas of the world are, according to our +present knowledge, inhabited by Cetaceans. A regular seasonal migration +has been observed in many of the oceanic Cetacea, especially those +inhabiting the North Atlantic, but further observations upon this subject +are still much needed. + +The great difference in the manner of life of the Sirenia, as compared +with that of the Cetacea, causes a corresponding difference in their +geographical distribution. Slow in their movements, and feeding +exclusively upon vegetable substances, water-grasses, or fuci, the +Sirenia are confined to rivers, estuaries, or coasts where these grow, +and are not denizens of the open sea, although of course there is a +possibility of accidental transport by the assistance of oceanic currents +across considerable distances. Of the three genera existing within +historic times, one (_Manatus_) is exclusively confined to the shores +of the tropical Atlantic and the rivers entering into it, individuals +scarcely specifically distinguishable being found both on the American +and the African side of the ocean. The Dugong (_Halicore_) is distributed +in different colonies, at present isolated, throughout the Indian Ocean +from Arabia to North Australia. The _Rhytina_ or Northern Sea-Cow was, +for some time before its extinction, limited to a single island in the +extreme north of the Pacific Ocean. + +The Pinnipeds, although capable of traversing long reaches of ocean, are +less truly aquatic than the last two groups, always resorting to the land +or to extensive ice-floes for the purpose of breeding. The geographical +range of the various species is generally more or less restricted, +usually according to climate, as they are mostly inhabitants either of +the Arctic or Antarctic seas and adjacent temperate regions, very few +being found within the tropics. For this reason the northern and the +southern species are for the most part quite distinct. In fact, the only +known exception is the case of a colony of the Sea-Elephant (_Macrorhinus +leoninus_), the general range of which is in the southern hemisphere, +inhabiting the coast of California. Even in this case a different +specific name has been given to the northern form; but the characters +by which it is distinguished are not of great importance, and probably, +except for the abnormal geographical distribution, would never have been +noticed. The most remarkable circumstance connected with the distribution +of the Pinnipeds is the presence of members of the suborder in the three +isolated great lakes or inland seas of Central Asia—the Caspian, Aral, +and Baikal; these forms, notwithstanding their long isolation, having +varied but slightly from species now inhabiting the Polar Seas. + + +II. GEOLOGICAL DISTRIBUTION. + +_Geological Sequence._—In order to understand the geological +distribution, or in other words the distribution in time of mammals, it +is necessary to be acquainted with the chief divisions, or time-periods, +of the strata constituting the crust of the globe. These are shown in the +following table, which commences with the uppermost or most recent beds +and ends with the lowest and oldest. + + I. CAINOZOIC OR TERTIARY— + 1. Pleistocene—River alluvia, etc. + 2. Pliocene—Suffolk Crag. + 3. Miocene—Hempstead Beds of Hampshire. + 4. Eocene—Paris Gypsum and London Clay. + + II. MESOZOIC OR SECONDARY— + 1. Cretaceous—Chalk, Greensands, etc. + 2. Jurassic—Oolites and Lias. + 3. Triassic—Red Marls, Dolomites, etc. + + III. PALÆOZOIC OR PRIMARY— + 1. Permian—Beds overlying the Coal. + 2. Carboniferous—Coal-measures, etc. + 3. Devonian—Old Red Sandstone. + 4. Silurian—Wenlock Limestone, etc. + 5. Cambrian—Llanberis Slate, etc. + 6. Archæan—Gneiss and other schists. + +The names in the first column indicate the primary divisions or +life-periods, while those in the second column are the great systems, +each of which is again divided into minor groups, the popular names of +a few of these minor groups being given in the third column. There are +at present no means of arriving at any satisfactory conclusion as to the +absolute length of time indicated by either the primary or secondary +divisions; but there is little doubt that the whole of the Tertiary +period is only equal to a fraction of the Mesozoic as regards its +duration, while it is probable that the duration of the Mesozoic epoch +was largely exceeded by that of the Palæozoic. + +_Mesozoic Mammals._—The earliest date at which mammals are at present +known is in the upper part of the Triassic period, which forms the base +of the great Mesozoic epoch; and from this date they are represented more +or less abundantly in various horizons of the Jurassic and Cretaceous. + +The very rapid advances in our knowledge of these forms which have been +made in the last few years, especially in consequence of the explorations +of rich fossiliferous beds in North America, have not only completely +changed the present aspect of the science, but give such promise for +the future, that any sketch which we may now attempt of this branch of +the subject can only be regarded as representing a transient phase of +knowledge. It will be well, however, to gather together in this place the +leading facts now ascertained with regard to the most ancient forms, as, +owing to the uncertainty of their relationship with any of the existing +orders, they will be most conveniently treated of separately, while the +ascertained facts relating to the geological history of the forms more +nearly allied to those now living will be more appropriately described +under the account of the different groups into which the class may now be +divided. + +The remains of mammals which existed anterior to the Tertiary period +hitherto discovered nearly all belong to creatures of very small size, +many of the largest scarcely exceeding the common Polecat or Squirrel. +Some are known only by a few isolated teeth, others by nearly complete +sets of these organs, and the majority by more or less nearly perfect +specimens of the rami of the lower jaw. It is a very curious circumstance +that this part of the skeleton alone has been preserved in such a large +number of instances. Only very rarely has a nearly complete cranium been +found; and there is no satisfactory evidence of the structure of the +vertebral column of any single individual, and only one known case of a +complete limb.[29] The species already described from European strata +are numerous, although the number of genera and species has lately +been reduced. Of these by far the greater number have been found at a +single spot near Swanage in Dorsetshire, in a bed of calcareous mud only +forty feet long, ten feet wide, and averaging five inches in depth. The +marvellous results obtained by the exploration by Mr. S. H. Beckles of +this small fragment of the earth’s surface show by what accidents, as +it were, our knowledge of the past history of life has been gained, +and what may still remain in store where little thought of at present. +A bed, apparently equally rich, has been discovered in the Jurassic of +Wyoming, North America, the contents of which have been made known by +Professor Marsh, while another fertile source of these remains occurs in +the Laramie beds of the Upper Cretaceous of the United States.[30] + +The whole of the Mesozoic mammals at present known may be divided into +two great groups, the one characterised by a type of dentition more or +less clearly resembling that found among the existing Polyprotodont +Marsupials, while the other presents an altogether peculiar modification, +recalling in some respects that of the Diprotodont Marsupials, although +differing so decidedly as to show that the owners of this form of +dentition cannot be included in that group. + +[Illustration: FIG. 24.—Frontal and oral aspects of the cranium of +_Tritylodon longævus_; from the Karoo system of Basuto-land, South +Africa. ⅔ natural size. (After Owen.)] + +_Multituberculata._—The name Multituberculata has been proposed for +the group exhibiting the type of dentition last mentioned, and is +generally adopted, although the term Allotheria has been also suggested. +The essential characteristic of the dentition of this group is the +presence of a single scalpriform incisor on each side of the lower +jaw (Fig. 25) and of one larger incisor, and in some instances of one +or two smaller ones in each premaxilla (Fig. 24). These incisors are +separated by an interval or diastema from the first of the premolars. +The true molars, and in some instances the premolars (Fig. 24), are +characterised by having longitudinal rows of tubercles separated by +one or more grooves; there being either two or three of these rows in +the upper molars of those forms in which these teeth are known, while +there are, at least usually, only two in those of the lower jaw. In +other cases the premolars are of a secant type, with a highly convex +cutting-edge, and usually either serrated or obliquely grooved (Figs. +25, 26). From a certain resemblance between these secant premolars and +those of some of the smaller _Macropodidæ_ it was at one time considered +that we had in these mammals representatives of Diprotodont Marsupials. +The great difference in the structure of the molar teeth of these forms, +coupled with the circumstance that when the number of upper incisors is +reduced below three it is the second in place of the first which becomes +enlarged and opposed to the incisor of the lower jaw, seems to prevent +the acceptation of this view. Moreover, in their peculiar structure +the molars seem, on the whole, to make a nearer approximation to the +teeth of _Ornithorhynchus_ than to any other known mammal; and it has +accordingly been suggested that the Multituberculata may really represent +an order of Prototheria. Some support is afforded to this suggestion by +certain fragmentary bones from the Cretaceous of the United States, which +are regarded by Marsh as parts of a coracoid and interclavicle. The +peculiar character of the whole dentition of these forms indicates that +if they are really Prototherians they cannot be regarded as primitive and +ancestral types. + +[Illustration: FIG. 25.—The right ramus of the mandible of _Plagiaulax +beklesi_; from the Purbeck of Swanage. Twice natural size. _i_, Incisor; +_m_, molar; _b_, coronoid process; _c_, condyle. (After Owen.)] + +It would be beyond the scope of the present work to describe in detail, +or even to mention the names of all the members of this group, and it +will therefore suffice to refer to a few of the principal types. Of the +forms with tubercular premolars the best known is the genus _Tritylodon_ +(Fig. 24), which occurs typically in beds of Lower Mesozoic in South +Africa, but is also known from the Trias of Stuttgart. In the Stonesfield +Slate, near Oxford, which belongs to the lower part of the Jurassic +system, and is separated from the Trias by the intervening Lias, a +fragmentary jaw with three teeth (Fig. 27) appears to indicate an allied +type, the teeth having three longitudinal ridges separated by grooves. +In the Purbeck beds of Dorsetshire, forming the top of the Jurassic +system, we find another member of this group, which has been described as +_Bolodon_, closely allied to which is _Allodon_ of the Upper Jurassic of +the United States. + +[Illustration: FIG. 26.—The imperfect right ramus of the mandible +of _Plagiaulax minor_; from Swanage. Four times natural size. _p_, +Premolars; _m_, molars. (After Lyall.)] + +The first discovery of the remains of Mesozoic mammals was made in the +Keuper or Upper Trias of the Rhætian Alps in Bavaria. In 1847 Professor +Pleininger of Stuttgart, while sifting some sand from the Keuper of +Diegerloch and Steinenbronn, found, among an immense mass of teeth, +scales, and unrecognisable fragments of skeletons of fish and saurians, +two minute teeth, each with well-defined, enamelled, tuberculated crowns +and distinct roots, plainly showing their mammalian character. These were +considered by their discoverer to indicate a predaceous and carnivorous +animal of very small size, to which he gave the name of _Microlestes +antiquus_. Subsequently Mr. C. Moore discovered in a bone bed of Rhætic +(topmost Trias) age, filling a fissure in the Mountain Limestone at +Holwell, near Frome in Somersetshire, various isolated teeth with their +crowns much worn, but apparently including both upper and lower molars +and a canine, which are assigned by Sir R. Owen to Pleininger’s genus +_Microlestes_, and described specifically as _M. moorei_. Under the name +of _Hypsiprymnopsis rhæticus_, Professor Boyd Dawkins described a single +tooth with two roots discovered in the Rhætic Marlstone at Watchet in +Somersetshire. Sir R. Owen referred the latter tooth to _Microlestes_, +and if its describer is right in regarding it as a much worn premolar of +the type of those of _Plagiaulax_ (Fig. 25) there would be evidence that +_Microlestes_ was closely allied to the latter, from the molars of which +those of _Microlestes_ are scarcely distinguishable. + +[Illustration: FIG. 27.—_Stereognathus oölithicus_. Fragment of jaw with +three teeth (_a_, _b_, _c_), in matrix; from the Stonesfield Slate. +Natural size. (After Owen.)] + +_Plagiaulax_, of the Dorsetshire Purbeck (Figs. 24, 25), is at once +distinguished from _Tritylodon_ by its secant premolars, which, as +already mentioned, recall those of some of the _Macropodidæ_, although +readily distinguished by the convexity of the cutting edge and their +oblique grooving. This remarkable and highly specialised type has +been the occasion of one of the most interesting discussions on the +inferences which may be drawn as to the affinities and habits of an +otherwise unknown animal from the structure of a small portion of +its organisation which occurs in the annals of natural history—a +discussion carried on with great ability, ingenuity, and wealth of +illustration on both sides. Dr. Falconer maintained that it was more +nearly allied to the Rat-Kangaroo (_Potorous_ or _Hypsiprymnus_) than +to any other existing form, and that, as it is known that these animals +feed upon grass and roots, “it may be inferred of _Plagiaulax_ that +the species were herbivorous or frugivorous. I can see nothing in the +character of their teeth,” he adds, “to indicate that they were either +insectivorous or omnivorous.” Sir R. Owen, on the other hand, from the +same materials came to the conclusion that “the physiological deductions +from the above-described characteristics of the lower jaw and teeth of +_Plagiaulax_ are that it was a carnivorous Marsupial. It probably found +its prey in the contemporary small insectivorous mammals and Lizards, +supposing no herbivorous form like _Stereognathus_ to have co-existed +during the Upper Oolitic period.” + +It is impossible here to give at any length the arguments by which these +opposing views are respectively supported, but it may be indicated that +the first-mentioned is strongly countenanced by the consideration of the +following facts: (1) all existing Marsupials may be divided, so far as +their dentition is concerned, into two groups—(_a_) those which have a +pair of large more or less procumbent incisors close to the symphysis of +the lower jaw, and rudimentary or no canines (diprotodont dentition), and +(_b_) those which have numerous small incisors and large pointed canines +(polyprotodont dentition); (2) the vast majority of the former group are +purely vegetable feeders, and almost all of the latter are carnivorous or +insectivorous; and (3) _Plagiaulax_, so far as its structure is known, +shows an analogy with the former group; and, as we have no sure basis for +inferences as to the habits of an unknown animal, but the knowledge of +the habits of such as are known, we have no grounds for supposing that +its habits differed from those forms having an analogous type of dental +structure.[31] + +Allied types, such as _Ctenacodon_, are also met with in the Upper +Jurassic of North America; and the _Plagiaulacidæ_ also persisted +into the lower part of the Eocene division of the Tertiary period; +_Neoplagiaulax_ being a Tertiary form common to Europe and the United +States, while _Liotomus_ and _Ptilodus_ are at present known only from +the latter country. + +The present group is also represented in the upper Cretaceous of the +United States by _Selenacodon_ (_Meniscoëssus_ in part), _Cimoliomys_, +etc. _Polymastodon_, of the Lowest or Puerco Eocene of New Mexico is the +largest known form, and is characterised by the presence of only one +premolar and the elongated molars. The angle of the mandible is inflected +after the Marsupial fashion. + +_Polyprotodont Types._—The second type of mammalian dentition found in +the Mesozoic period resembles that occurring among recent Polyprotodont +Marsupials—that is to say there are at least three lower incisors, the +canines are well developed, and the premolars and molars are cuspidate, +the number of the latter reaching in some cases to seven or eight. There +has been much discussion as to the taxonomic position of these forms, and +while the majority of writers admit the Marsupial affinities of at least +a moiety, it has been contended that others indicate distinct ordinal +groups more or less closely allied to the Insectivora. At present, +however, there is no decisive evidence to support such a view. Important +proof of the Marsupial affinity of one of these forms is afforded by +the replacement of the teeth, which appears to be of the same nature as +in the existing Marsupials, that is to say, the last premolar alone is +preceded by a milk-tooth. + +The most generalised forms appear to be _Dromatherium_ and +_Microconodon_, from Lower Mesozoic beds in the United States, of which +enlarged views of the teeth are given in Fig. 4 (1, 2), p. 31. Professor +Osborn points out the extremely simple character of these teeth, and it +is quite possible that these forms may prove to be _Prototheria_. There +are three premolars and seven molars in the lower jaw of _Dromatherium_. + +[Illustration: FIG. 28.—Reversed view of the left ramus of the mandible +of _Triconodon mordax_; from the Purbeck of Swanage. Natural size. (After +Owen.)] + +A common form in the Purbeck of Dorsetshire is _Triconodon_ +(_Triacanthodon_), in which the formula of the lower teeth is _i_ 3, +_c_ 1, _p_ 4, _m_ 3-4. A lower jaw is shown in Fig. 28, and an enlarged +view of a molar tooth in Fig. 4 (5). The molar teeth consist of three +flattened cones placed in the same antero-posterior line, those of +the upper and lower jaw being alike. _Priacodon_, of the Jurassic of +the United States, is probably inseparable from _Triconodon_. In the +genus _Phascolotherium_ (Fig. 29) of the Lower Jurassic Stonesfield +Slate, the lower teeth may be classified as _i_ 4, _c_ 1, _p_ 3, _m_ +4, the premolars and molars being much alike. The molars approximate +to the type of those of _Triconodon_, but the anterior and posterior +cones are relatively smaller. Like that of the last-named genus, the +mandible of _Phascolotherium_ is remarkable for the extremely low +position of its articular condyle. In _Amphilestes_ (Fig. 30) of the +Stonesfield Slate the molars appear to be of the same general type as +those of _Phascolotherium_, but are more numerous, although their exact +number cannot be determined. A somewhat different type of lower molar +is displayed by the genus _Amblotherium_, of the Dorsetshire Purbeck, +to which _Amphitherium_ of the Stonesfield Slate was probably allied. +This type of tooth is shown in Fig. 4 (8, 9, 12) p. 31, and, as there +stated, represents that modification of the tritubercular type known +as the tubercular sectorial. The three primitive tritubercular cusps +form what is known as the blade of the tooth, behind which there is +the talon or hypocone. A similar form of molar occurs in the existing +Opossums and Bandicoots. The number of lower teeth in _Amblotherium_ is +_i_ 4, _c_ 1, _p_ 4, _m_ 7-8. Numerous allied types, such as _Achyrodon_ +and _Dryolestes_ occur in the Upper Jurassic of Europe or the United +States, while from only one side of the jaw being exposed in each case +so-called genera like _Stylodon_ and _Stylacodon_ have been formed upon +specimens showing the opposite side to that which is exposed in the +types of _Amblotherium_ and _Amphitherium_. The only parallel among +existing forms to the excessive number of molar teeth found in these +Mesozoic genera occurs in the Marsupial genus _Myrmecobius_, of which a +description is given in a succeeding chapter. Jaws more or less closely +resembling those described under the names mentioned above are also found +in the uppermost Cretaceous of the United States. A feature common to +these Mesozoic mammals and _Myrmecobius_ and some other existing forms +is the presence of a narrow channel on the inner side of the mandibular +ramus known as the mylohyoid groove (Fig. 29). + +[Illustration: FIG. 29.—Inner view of the right ramus of the mandible +of _Phascolotherium bucklandi_; from the Stonesfield Slate. The outline +shows the natural size. _i_, Incisors (one missing); _c_, canine; _p_, +premolars; _m_, molars. The mylohyoid groove is seen near the lower +border. (After Owen.)] + +[Illustration: FIG. 30.—Reversed inner view of the left ramus of the +mandible of _Amphilestes broderipi_; from the Stonesfield Slate. Twice +natural size. The restoration of the anterior teeth is conjectural, and +the condyle is placed too high. (After Owen.)] + +The last type of molar dentition occurring among the Mesozoic +Mammalia is that found in the lower jaws (Fig. 31), upon which the +genus _Spalacotherium_ was established, the upper jaws, described as +_Peralestes_, being apparently referable to the same animal. Upper +and lower teeth of this form are represented in Fig. 4 (6, 7), p. 31, +where they are described as typical examples of the tritubercular type +of molars, the upper teeth having one inner and two outer cusps, and +the reverse condition obtaining in the lower ones. This type of molar +presents a marked resemblance to that found in the existing Insectivorous +genus _Chrysochloris_; the number of lower teeth in _Spalacotherium_ is, +however, _i_ 3, _c_ 1, _p_ + _m_ 10, by which it is widely distinguished +from all the Insectivora. _Menacodon_, of the Upper Jurassic of the +United States, appears to be allied to _Spalacotherium_. + +[Illustration: FIG. 31.—Part of the left ramus of the mandible, viewed +from the outer side, of _Spalacotherium tricuspidens_; from the Purbeck +of Swanage. Twice natural size. (After Owen.)] + +_Tertiary Mammals._—The more important types of Tertiary mammals will, +as already mentioned, be noticed under the heads of the groups to which +they are severally allied; but a few general remarks on this subject may +be advantageously recorded in this chapter. In the first place, it may +be observed that the comparatively scanty evidence of mammalian life +hitherto yielded by the Cretaceous, coupled with the number and variety +of forms approximating to the existing groups found even in the lowest +Tertiary, indicates a great imperfection of the geological record. At +present, indeed, we have no decisive evidence of the existence of any +members of the Eutherian subclass previously to the Tertiary; but it can +hardly be doubted that in some part of the world they had made their +appearance before that epoch. The Eutherian mammals of the lowest Eocene, +both in Europe and the United States, are of an extremely generalised +type; and although many of them approximate to existing groups, they show +such a combination of characters, now restricted to individual groups, as +to indicate that several of the various orders into which the subclass +is now divided were at that period very intimately connected. A marked +feature of these early Eutherians is the prevalency of trituberculism +in the dentition, not less noteworthy being the frequent occurrence of +pentadactylism in the feet, while many of the individual bones were +devoid of the grooves and ridges found in those of later types. By the +time that we reach the upper division of the Eocene period, such as the +horizon of the well-known gypsum of the Paris basin, nearly all the chief +groups of mammals had become clearly differentiated from one another, +although their representatives were usually more generalised than their +existing allies. From this date to the later geological periods there is +a gradual approximation to the types of mammalian life existing at the +present day. + +In addition to the features of trituberculism and pentadactylism so +characteristic of the oldest known Eutherians, we may notice some other +points in connection with the earlier types. Thus the older Tertiary +mammals, as we have already stated, had relatively smaller and simpler +brains than the later types, so that a gradual evolution in this respect +may be traced from the Eocene to the Pleistocene. Again, there is a +great tendency among the Eocene forms to a retention of the typical +Eutherian dental formula noticed on page 25, and also to the absence of +an interval, or diastema, in the dental series. Concomitantly with this +feature we may notice the short crowns and simpler structure of the molar +teeth of the earlier Ungulates as compared with those of to-day, of which +details will be given in a later chapter. Another instance of the more +generalised characters of the earlier mammals is afforded by the absence +or slight development of horns, antlers, and tusks among the Ungulata. +Thus the earlier Rhinoceroses were hornless, and the Deer either without +antlers or with antlers of a very simple kind, while the male Swine were +not furnished with the formidable tusks of the existing Wild Boars. +Finally, all, or nearly all of the mammals, from the lowest Eocene of +Rheims present the peculiarity of having a vertical perforation in the +astragalus. + +The intimate connection existing during the Middle Tertiary between many +families of mammals now widely distinguished from one another may be more +conveniently noted when we come to the consideration of the families in +question. + + + + +CHAPTER V + +THE SUBCLASS PROTOTHERIA OR ORNITHODELPHIA + + +_General Characters._—The characters of the Prototheria can at present +only be deduced from the two existing families, since hitherto no extinct +animals which can be referred with certainty to other divisions of this +remarkable and well-characterised group have been discovered. These two +isolated forms, in many respects widely dissimilar, yet having numerous +common characters which unite them together and distinguish them from the +rest of the Mammalia, are the _Ornithorhynchidæ_ and the _Echidnidæ_, +both restricted in their geographical range to the Australian region +of the globe. Taken altogether they represent the lowest type of +evolution of the mammalian class, and most of the characters in which +they differ from the other two subclasses tend to connect them with the +inferior vertebrates, the Sauropsida and Amphibia; for, though the name +Ornithodelphia owes its origin to the resemblance of the structure of the +female reproductive organs to those of birds, there is nothing especially +bird-like about them. + +Their principal distinctive characters are these. The brain has a very +large anterior commissure, and a very small corpus callosum, agreeing +exactly in this respect with the Marsupials. The cerebral hemispheres, +in _Echidna_ at least, are well developed and convoluted on the surface. +The auditory ossicles present a low grade of development, the malleus +being very large, the incus small, and the stapes columelliform. The +coracoid bone is complete, and articulates with the sternum, and there +is a pre-coracoid (epi-coracoid) in advance of the coracoid, while there +is also a large “interclavicle” or episternum in front of the sternum, +and connecting it with the clavicles. There are also “epipubic” bones. +The oviducts (not differentiated into uterine and Fallopian portions) are +completely distinct, and open, as in oviparous vertebrates, separately +into a cloacal chamber, and there is no distinct vagina. The testes +of the male are abdominal in position throughout life, and the vasa +deferentia open into the cloaca, not into a distinct urethral passage. +The penis, attached to the ventral wall of the cloaca, is perforated by +a canal in the greater part of its length, and not merely grooved, as in +reptiles and those birds which have such an organ. The canal is open at +the base and brought only temporarily in contact with the termination of +the vasa deferentia, so as to form a seminal urethra when required; but +it never transmits the urinary secretion. This condition is a distinct +advance on that of the Sauropsida in the direction of the more complex +development of these parts in most of the other Mammalia. The ureters +do not open into the bladder, but behind it into the dorsal wall of the +genito-urinary passage. The mammary glands have no distinct nipple, +but pour out their secretion through numerous apertures situated in a +cup-shaped depression of the abdominal skin, forming a mammary marsupium, +especially developed in the females during lactation. It should be +mentioned that, according to the observations of Professor Gegenbaur, the +mammary glands of the Monotremes are the simplest found in the entire +class. The region of the glands is, indeed, distinguished from the rest +of the abdomen merely by its thicker layers of muscles. The glands +themselves are closely connected with the hair-follicles, and belong to +the sudoriparous type, whereas the glands of all other mammals are of +sebaceous origin. + +The young are produced from eggs laid by the female parent, which are +meroblastic, like those of birds; that is to say only a portion of +the yolk segments and forms the embryo, the remainder serving for the +nourishment of the latter. + +The above are the principal distinguishing characters of the group, and +apply not only to the subclass, but of course equally to the one order +Monotremata, in which the two existing genera are included. In addition +to these more important characters, the following minor features may also +be mentioned. + +The scapula differs from that of all other mammals in that the ridge +corresponding to the spine of other forms is situated on the anterior +border instead of in the middle of the outer or dorsal surface. The +humerus is much expanded at its two extremities, and has a very prominent +deltoid crest, and a well-marked entepicondylar foramen. + +The dorso-thoracic vertebræ are nineteen in number, and have no terminal +epiphyses to their bodies. The transverse processes of the cervical +vertebræ are of autogenous formation, and remain suturally connected with +the remainder of the vertebra until the animal is full-grown. Though in +this respect they present an approximation to the Sauropsida (Reptiles +and Birds), they differ from these classes, inasmuch as there is not a +gradual transition from these autogenous transverse processes of the neck +(or cervical ribs, as they may be considered) into the thoracic ribs, for +in the seventh vertebra the costal element is much smaller than in the +others, indicative of a very marked separation of neck from thorax, not +seen in the existing Sauropsida. The upper ends of the ribs are attached +to the sides of the bodies of the dorsal vertebræ only, and not to the +transverse processes. The sternal ribs are well ossified, and there are +distinct partly ossified intermediate ribs. The cerebral cavity, unlike +that of the lower Marsupials or the Reptiles, is large and hemispherical, +flattened below and arched above, and about as broad as long. The +cribriform plate of the ethmoid is nearly horizontal. The cranial walls +are very thin, and smoothly rounded externally, and the sutures become +completely obliterated in adult skulls, as in Birds. The broad occipital +region slopes upwards and forwards, and the face is produced into a long +and depressed rostrum. The bony palate is prolonged backwards, so that +the posterior nares are nearly on a level with the glenoid fossæ. The +mandible is without distinct ascending ramus; the coronoid process and +angle are rudimentary, and the two halves are loosely connected at the +symphysis. The fibula has a broad, flattened process, projecting upwards +from its upper extremity above the articulation, like an olecranon. In +the male there is an additional, flat, curved ossicle on the hinder and +tibial side of the plantar aspect of the tarsus, articulating chiefly +to the tibia, which supports in the adult a sharp-pointed perforated +horny spur, with which is connected the duct of a gland situated +beneath the skin of the back of the thigh, the function of which is +not yet clearly understood. (A rudimentary spur is found in the young +female _Ornithorhynchus_, but this disappears when the animal becomes +adult.) The stomach is subglobular and simple; the alimentary canal +has no ileo-cæcal valve, or marked distinction between large and small +intestine, but has a small, slender vermiform cæcum with glandular walls. +The liver is divided into the usual number of lobes characteristic of the +Mammalia, and is provided with a gall-bladder. + +In the presence of three distinct bones developed from cartilage in the +shoulder-girdle (viz. scapula, coracoid, and pre- or epi-coracoid) the +Monotremes agree with the Anomodont reptiles (see p. 83), and with no +other representatives of that class. The pre-coracoid of the Anomodonts +is, however, distinguished by extending upwards to articulate with the +acromial process of the scapula. The Monotreme humerus is, moreover, +strikingly like the corresponding bone of many of the Anomodonts and of +some of the allied Labyrinthodont Amphibians. + + +_Family_ ORNITHORHYNCHIDÆ. + +_Ornithorhynchus._[32]—Cerebral hemispheres smooth. Premaxillæ and +mandible expanded anteriorly and supporting a horny beak something +like that of a duck, bordered by a naked and very sensitive membranous +expansion. The place of teeth in the adult is supplied functionally by +horny structures, elongated, narrow, and sharp-edged, along the anterior +part of the sides of the mouth, and broad, flat-topped or molariform +behind. Functional molar teeth present in the young and adolescent +condition. Legs short, fitted for swimming; feet webbed, each with five +well-developed toes armed with large claws, beyond which in the fore feet +the interdigital membrane is extended. Vertebræ: C 7, D 17, L 2, S 2, +Ca 21. Acetabulum not perforated. Tongue not extensile. Mucous membrane +of small intestine covered with delicate, close-set transverse folds or +ridges. Tail rather short, broad, and depressed. Eyes very small. Fur +close and soft. + +The Duck-billed Platypus (_Platypus anatinus_) was the name assigned to +one of the most remarkable of known animals by Shaw, who had the good +fortune to introduce it to the notice of the scientific world in the +_Naturalist’s Miscellany_ (vol. x., 1799). In the following year it was +independently described by Blumenbach (_Voigts Magazin_, ii. p. 205) +under the name of _Ornithorhynchus paradoxus_. Shaw’s generic name, +although having priority to that of Blumenbach, could not be retained, as +it had been used at a still earlier time (1793) by Herbst for a genus of +Coleoptera. _Ornithorhynchus_ is therefore now universally adopted as the +scientific designation, although Duck-billed Platypus or Duck-bill may be +conveniently retained as a vernacular appellation. By the colonists it is +called “Water-Mole,” but it need scarcely be said, its affinities with +the true moles are of the slightest and most superficial description. +Until the last few years the early stages of the development of the young +were not fully known. It had, indeed, been repeatedly affirmed, in some +cases by persons who have had actual opportunities of observation, that +the Platypus lays eggs; but these statements were generally received +with scepticism and even denial. This much-vexed question was, however, +settled by the researches of Mr. W. H. Caldwell in 1884, who found that +these animals, although undoubtedly mammals throughout the greater part +of their structure, are oviparous, laying eggs, which in the manner of +their development bear a close resemblance to the development of those +of the Reptilia. Two eggs are produced at a time, each measuring about +three-fourths of an inch in its long, and half an inch in its short, +axis, and enclosed in a strong, flexible, white shell. + +The Platypus is pretty generally distributed in situations suitable to +its aquatic habits throughout the island of Tasmania and the southern and +eastern portions of Australia. Slight variations in the colouring and +size of different individuals have given rise to the idea that more than +one species may exist; but all naturalists who have had the opportunity +of investigating this question by the aid of a good series of specimens +have come to the conclusion that there is but one, and no traces of any +extinct allied forms have yet been discovered. + +[Illustration: FIG. 32.—Platypus or Duck-bill (_Ornithorhynchus +anatinus_). From Gould’s _Mammals of Australia_.] + +The length of the animal when full grown is from eighteen to twenty +inches from the extremity of the beak to the end of the tail, the male +being slightly larger than the female. The fur is short, dense, and +rather soft to the touch, and composed of an extremely fine and close +under-fur, and of longer hairs projecting beyond this, each of which is +very slender at the base, and expanded, flattened, and glossy towards +the free end. The general colour is deep brown, but paler on the under +parts. The tail is short, broad, and depressed, and covered with coarse +hairs, which in old animals generally become worn off from the under +surface. The eyes are small and brown. There is no projecting pinna or +ear-conch. The mouth, as is well known, bears a striking resemblance +to the bill of a Duck. It is covered with a naked skin, a strong fold +of which projects outwards around its base. The nostrils are situated +near the extremity of the upper surface. There are no true teeth in the +adult, but their purposes are served by horny prominences, or cornules, +two on either side of each jaw—those in the front, narrow, longitudinal, +sharp-edged ridges, and those behind broad, flattened, and molariform. +The upper surface of the lateral edges of the mandible has also a +number of parallel fine transverse ridges, like those on the bill of a +Duck. Until 1888 it was thought that true teeth were totally wanting +throughout the life of this animal; but in the spring of that year Mr. E. +B. Poulton[33] announced the discovery in an embryo of teeth which were +regarded as quite functionless. In the following year, however, Mr. O. +Thomas[34] was fortunate enough to find some young skulls with functional +teeth _in situ_, and was thus enabled to give a detailed account of their +structure and of their relations to the cornules. From those specimens +it appears that the teeth are functional for a considerable part of the +life of the animal, cutting the gum in the usual manner, and, after being +worn down by friction with food and sand, are shed from the mouth in the +same manner as are the milk-teeth of other mammals. The cornules are +developed from the epithelium of the mouth under and around the teeth, +and the hollows found in the middle of them are the vestiges of the +alveoli from which the teeth have been shed. One of the skulls showed on +either side, both above and below, two completely calcified teeth; but in +another example there were three teeth on either side of the lower jaw. +According to Mr. Thomas’s account, “the teeth themselves are broad, flat, +and low-crowned. The upper ones have each two high, conical, internal +cusps, from which minute ridges run downwards and outwards to the outer +borders of the crowns, where the edge is peculiarly crenulate rather than +cuspidate, in the ordinary sense of the word. On the whole, the anterior +and posterior upper teeth are essentially similar to one another, except +that the former are narrower, and their outer edges are less markedly +crenulated. In the lower jaw there is a greater difference between the +two. The anterior is triangular in outline, its longest side is placed +antero-externally, and its anterior and postero-external angles have each +a high pointed cusp, ridged on its internal aspect, while the posterior +and internal borders are indistinctly crenulated. The posterior tooth is +broadly quadrangular in outline, with a projecting antero-internal angle. +As in the corresponding tooth above, there are two cusps on one side, and +a series of crenulations on the other, but they are of course reversed, +the cusps being external and the crenulations internal. The cusps are +high, and connected with transverse ridges running across towards the +internal border.” + +In trying to find any teeth like those of the Duck-bill among other known +mammals Mr. Thomas considers, as was first suggested by Professor Cope, +that those of the Mesozoic Multituberculata (p. 109) make the nearest +approximation. He adds, however, that “it must be insisted that the +resemblance between the Multituberculate and the Ornithorhynchus teeth +is of the most general character, and that the two are certainly widely +separated generically, even if we do admit that they appear to possess +a relationship nearer to each other than to any other known groups of +mammals.” + +Reverting to the description of the Duck-bill, we find that in the +cheeks are tolerably capacious pouches, which appear to be used as +receptacles for food. The limbs are strong and very short, each with +five well-developed toes provided with strong claws. In the fore feet +the web not only fills the interspaces between the toes, but extends +considerably beyond the ends of the long, broad, and somewhat flattened +nails, giving great expanse to the foot when used for swimming, though +capable of being folded back on the palm when the animal is burrowing +or walking on the land. On the hind foot the nails are long, curved, +and pointed, and the web extends only to their base. On the heel of the +male is a strong, curved, sharply pointed, movable horny spur, directed +upwards and backwards, attached by its expanded base to the accessory +bone of the tarsus. This spur, which attains the length of nearly an +inch, is traversed by a minute canal, terminating in a fine longitudinal +slit near the point, and connected at its base with the duct of a large +gland situated at the back part of the thigh. The whole apparatus is so +exactly similar in structure to the poison-gland and tooth of a venomous +snake as to suggest a similar function, but evidence that the Platypus +ever employs its spur as an offensive weapon has, at all events until +lately, been wanting. A case is, however, related by Mr. Spicer in the +_Proceedings of the Royal Society of Tasmania for 1876_ (p. 162), of a +captured Platypus inflicting a severe wound by a powerful lateral and +inward movement of the hind legs, which wound was followed by symptoms of +active local poisoning. It is not improbable that both the inclination +to use the weapon and the activity of the secretion of the gland may +be limited to the breeding season, and that their purpose may be, like +that of the antlers of deer and many similar organs, for combat among +the males. In the young female the spur is present in a rudimentary +condition, but it disappears in the adult of that sex. + +The Platypus is aquatic in its habits, passing most of its time in the +water or close to the margin of lakes and streams, swimming and diving +with the greatest ease, and forming for the purpose of sleeping and +breeding deep burrows in the banks, which generally have two orifices—one +just above the water level, concealed among long grasses and leaves, +and the other below the surface. The passage at first runs obliquely +upwards in the bank, sometimes to a distance of as much as fifty feet, +and expands at its termination into a cavity, the floor of which is lined +with dried grass and leaves, and in which the eggs are laid and the young +brought up. The food consists of aquatic insects, small crustaceans, and +worms, which are caught under water, the sand and small stones at the +bottom being turned over with the bill. The creatures appear at first to +deposit what they have thus collected in their cheek pouches, and when +these are filled they rise to the surface and quietly triturate their +meal with the horny plates before swallowing it. Swimming is effected +chiefly by the action of the broad forepaws, the hind feet and tail +taking little share in locomotion in the water. When asleep they roll +themselves into a ball, as shown in the figure. In their native haunts +they are extremely timid and wary, and very difficult to approach, being +rarely seen out of their burrows in the daytime. Mr. A. B. Crowther, who +has supplemented the often quoted observations of Dr. Bennett upon the +habits of these animals in confinement, says, “They soon become very +tame in captivity; in a few days the young ones appeared to recognise a +call, swimming rapidly to the hand paddling the water; and it is curious +to see their attempts to procure a worm enclosed in the hand, which they +greedily take when offered to them. I have noticed that they appear to be +able to smell whether or not a worm is contained in the closed hand to +which they swim; for they desisted from their efforts if an empty fist +was offered.” When irritated they utter a soft low growl, resembling that +of a puppy. + + +_Family_ ECHIDNIDÆ. + +Cerebral hemispheres larger and well convoluted. Facial portion of skull +produced into a long, tapering, tubular rostrum, at the end of which +the anterior nares are situated. Rami of mandible slender, styliform. +Opening of mouth small, and placed below the extremity of the rostrum. +No teeth or laterally placed horny plates, though the palate and tongue +are furnished with spines. Tongue very long, vermiform, slender, and +protractile. Lining membrane of small intestine villous, but without +transverse folds. Feet not webbed, but with long strong claws fitted +for scratching and burrowing. The hinder feet with the ends of the toes +turned outwards and backwards in the ordinary position of the animal when +on the ground. Tail very short. Acetabulum with a large perforation, +as in Birds. Calcaneal spur and gland of the male much smaller than in +_Ornithorhynchus_. Fur intermixed with strong, sharp-pointed spines. +Terrestrial and fossorial in habits, feeding exclusively on ants, and +recalling in the structure of the mouth and various other parts, relating +to their peculiar mode of life the true Anteaters of the order Edentata. + +The Echidnas or Spiny Anteaters constitute a family which appears in some +respects to be less specialised than the _Ornithorhynchidæ_. According +to Mr. O. Thomas, all the living forms may be included in two species, +which, with some hesitation, are referred to two genera—_Echidna_ and +_Proechidna_ (_Acanthoglossus_). + +_Echidna._[35]—In _Echidna_ there are five toes, all of which are +provided with claws, those of the fore foot being broad, slightly curved, +and directed forwards, while the posterior ones are slender, more curved, +and inclined outwardly. The beak is about as long as the rest of the +head, and either nearly straight, or slightly curved upwards, while the +palate is comparatively wide, and but slightly vaulted. The number of the +vertebræ is C 7, D 16, L 3, S 3, Ca 12. The one existing representative +of the genus (_E. aculeata_) occurs in New Guinea, Tasmania, and +Australia. + +So much variation is displayed by this animal, that it has been divided +into several species, but the latest researches tend to show that these +variations cannot be regarded as indicating more than races, of which +there are three well-marked types. + +The first race, or variety, has been termed the Port Moresby Echidna, +and is only known from that Papuan locality. It is distinguished from +the typical form by its smaller size, by the shorter spines on the back, +which admit of the fur being seen, and by the more spinous covering +of the head, belly, and limbs, as well as by the lighter skull and +relatively larger beak. + +The typical variety is confined to the Australian mainland, and is of +medium size. The spines of the back are very long and stout, often +reaching a length of two inches, and almost completely concealing the +hair. The colour of these spines varies from yellow at the roots to black +at the tips, but some may be altogether yellow. The hair of the back is +black or dark brown in colour, but it may be occasionally absent, or +in the region of the loins may exceed the spines in length. The limbs +and under surface of the body are covered with dark brown hair, thinly +interspersed with short spines; and the hair of the face is of the same +general hue as that of the body. The skull has a slender rostrum and a +flat and narrow brain-case. + +In the third or Tasmanian race, which is confined to Tasmania, the +average size is somewhat larger than in the typical form. The most +characteristic feature is, however, the shortness of the spines of the +back, which in the greater part of that region are almost or quite +concealed by the hairs. The hairs of the back are dark brown, those of +the under surface and sides of the head being generally rather paler. +There is often a white spot on the chest. Very frequently there is a +difference in the proportionate lengths of the hinder claws from those of +the typical race. In the skull the beak is comparatively short and stout, +and the brain-case large and wide. + +Echidnas are usually found in rocky districts, and more especially +in the mountains. In a wild state they live mainly on ants. Specimens +have been brought to this country and kept in the Zoological Society’s +Gardens; and in captivity they will readily eat eggs, and bread-and-milk. +They are able, however, to endure long fasts, an individual having been +known to go without food for upwards of a month. + +These animals seem to be mainly of nocturnal habits, and if brought out +during the daytime appear to be sluggish and stupid, crouching to the +ground with the head between the legs, and thus presenting a mass of +spines to an enemy. They burrow rapidly in soft ground, sinking directly +downwards, and not going head forwards. A specimen placed on a large +chest of earth containing plants reached the bottom in less than two +minutes; and it is said that the muzzle assists in the work of burrowing. + +[Illustration: FIG. 33.—The Three-toed Echidna (_Proechidna bruijnii_). +From Gervais.] + +_Proechidna._[36]—The one known representative of the genus _Proechidna_ +(Fig. 33) attains dimensions about equal to those of the largest race +of _Echidna aculeata_. The skull is less depressed than in the latter, +with the anterior portion of the palate very concave, and the deflected +beak nearly twice the length of the remainder of the skull. As a rule, +there are only three claws to each foot; but the first and fifth digits +are represented by several phalanges, and one instance is known where +there are five complete claws on the anterior and four on the posterior +feet. There are two more vertebræ in the dorsal and lumbar region than in +_Echidna_. + +The head and body are covered with a thick coat of hair, among which +there are a number of short spines in the region of the back, which are +much less numerous than in the typical race of the last species. The +colour of the fur is generally dark brown or black, but the head may be +almost white; and the spines are usually entirely white, although in +certain cases they may be brown at the root. + +This species is known only from New Guinea, the recorded specimens being +from the north-western regions of that country. It inhabits rocky ground, +and dwells chiefly in the mountains, the specimens which were first +described having been obtained at an elevation of about 3500 feet above +the sea level. The Papuans capture it by digging trenches in the ground +to a depth of about a yard, by which means they generally come upon its +runs. + +_Fossil Species._—Remains of a species of Echidna of very much larger +size than the existing forms have been obtained from the cave-deposits of +New South Wales, which appear to be of Pleistocene age. This species was +named _Echidna oweni_ by the late Mr. Krefft, but was subsequently called +_E. ramsayi_ by Sir R. Owen. In referring this species to the genus +_Echidna_, that term must be regarded as including _Proechidna_. + + + + +CHAPTER VI + +THE SUBCLASS METATHERIA OR DIDELPHIA + + +_General Characters._—The Metatheria or Didelphia are represented at +present by numerous species, presenting great diversities of general +appearance, structure, and habits, although all united by many essential +anatomical and physiological characters, which, taken altogether, give +them an intermediate position between the Prototheria and the Eutheria. + +Although the striking differences in external form, in many anatomical +characters, and in mode of life of various animals of this section +might lead to their division into groups equivalent to the orders of +the Eutheria, it is more convenient on the whole to adhere to the usual +custom of treating them all as forming one order called MARSUPIALIA,[37] +the limits of which are therefore equivalent to that of the subclass. The +more essentially distinctive characters are as follows. + +In the structure of the brain and the presence of epipubic bones they +agree with the Prototheria, while in the structure of the ear-bones and +the shoulder-girdle and the presence of teats on the mammary glands they +resemble the Eutheria, the reproductive organs belonging to neither +one nor the other type, but having a special character representing an +intermediate grade of development. The ureters open into the base of +the bladder. The oviducts are differentiated into uterine and Fallopian +portions, and open into a long and distinct vagina, quite separate from +the cystic urethra. The penis is large, but its crura are not directly +attached to the ischia. The spongy body has a large bifurcated bulb. +The young are born in an exceedingly rudimentary condition, and are +never nourished by means of an allantoic placenta, but are transferred +to the nipple of the mother, to which they remain firmly attached for +a considerable time, nourished by the milk injected into the mouth by +compression of the muscle covering the mammary gland. They are therefore +the most typically mammalian of the whole class. The nipples are nearly +always concealed in a fold of the abdominal integument or “pouch” +(marsupium) which serves to support and protect the young in their early +helpless condition. + +Entering more fully into the characters of the subclass, which are +also those of the order Marsupialia, it may be observed that the brain +is generally small in proportion to the size of the animal, and the +surface-folding of the cerebral hemispheres, though well marked in the +larger species, is never very complex in character, and is absent in the +medium-sized and smaller species. The arrangement of the folding of the +inner wall of the cerebrum differs essentially from that of all known +Eutheria, the hippocampal fissure being continued forward above the +corpus callosum, which is of very small size. The anterior commissure is, +on the other hand, greatly developed. + +[Illustration: FIG. 34.—Teeth of upper jaw of Opossum (_Didelphys +marsupialis_), all of which are unchanged, except the last premolar, the +place of which is occupied in the young animal by a molariform tooth, +represented in the figure below the line of the other teeth.] + +The teeth are always divisible, according to their position and form, +into incisors, canines, premolars, and molars; but they vary much in +number and character in the different families. Except in the genus +_Phascolomys_, the number of incisors in the upper and lower jaws is +never equal. The true molars are very generally four in number on either +side of each jaw. The chief peculiarity in the dentition lies, however, +in the mode of succession. Thus there is no vertical displacement and +succession of the teeth, except in the case of a single tooth on either +side of each jaw, which is always the hindermost of the premolar series, +and is preceded by a tooth having more or less of the characters of +a true molar (see Fig. 34); this deciduous tooth being the only one +comparable to the “milk-teeth” of the diphyodont Eutheria. In some cases +(as in _Potorous_) this tooth retains its place and function until the +animal has nearly, if not quite, attained its full stature, and is not +shed and replaced by its successor until after all the other teeth of +the permanent series, including the posterior molars, are fully in place +and use. In others, as the Thylacine, it is very rudimentary in form +and size, being shed or absorbed before any of the other teeth have +cut the gum, and therefore quite functionless. It must further be noted +that there are some Marsupials, as the Wombat, _Myrmecobius_, and the +Dasyures, in which no such milk-tooth, even in a rudimentary state, has +yet been discovered, possibly in some cases from want of materials for +observation at the right stage of development. + +Epipubic or marsupial bones are present in both sexes of nearly all +species. In one genus alone, _Thylacinus_, they are not ossified. The +number of dorso-lumbar vertebræ is always nineteen, although there are +some apparent exceptions caused by the last lumbar being modified into a +sacral vertebra. The number of pairs of ribs is nearly always thirteen. +The tympanic bone remains permanently distinct. The carotid canal +perforates the basisphenoid. The lachrymal foramen is situated upon or +external to the anterior margin of the orbit, and there are generally +large vacuities in the bony palate. The angle of the mandible is (except +in _Tarsipes_) more or less inflected. The hyoid bones have always +a peculiar form, consisting of a small, more or less lozenge-shaped +basihyal, broad ceratohyals, with the remainder of the anterior arch +usually unossified, and stout, somewhat compressed thyrohyals. There +are two anterior venæ cavæ,[38] into each of which a “vena azygos” +enters. In the male the testes are always contained in a scrotum, which +is suspended by a narrow pedicle to the abdomen in front of the penis. +The vasa deferentia open into a complete and continuous urethra, which +is also the passage by which the urine escapes from the bladder, and is +perfectly distinct from the passage for the fæces, although the anus +and the termination of the urethro-sexual canal are embraced by the +same sphincter muscle. The glans is often bifurcated anteriorly. In the +female the oviducts never unite to form a common cavity or uterus, but +open separately into the vagina, which at least for part of its course +is double. The mammæ vary much in number, but are always abdominal in +position, having long teats, and in most of the species are more or +less enclosed in a fold of the integument forming a pouch or marsupium, +though in some this is entirely wanting, and the newly-born, blind, +naked, and helpless young, attached by their mouths to the teat, are +merely concealed and protected by the hairy covering of the mother’s +abdomen. In this stage of their existence they are fed by milk injected +into their stomach by the contraction of the muscles covering the +mammary gland, the respiratory organs being modified temporarily, much +as they are permanently in the Cetacea—the elongated upper part of the +larynx projecting into the posterior nares, and so maintaining a free +communication between the lungs and the external surface independently +of the mouth and gullet, thus averting the danger of suffocation while +the milk is passing down the latter passage. + +[Illustration: FIG. 35.—Front view of skull of _Sarcophilus ursinus_, +showing polyprotodont and carnivorous dentition (_Quart. Journ. Geol. +Soc._ vol xxiv. p. 313).] + +_Distribution._—The existing species of Marsupials are, with the +exception of one family (the _Didelphyidæ_), limited in geographical +distribution to the Australasian region,[39] forming the chief mammalian +fauna of Australia, New Guinea, and some of the adjacent islands. The +_Didelphyidæ_ are almost purely Neotropical, one or two species ranging +northwards into the Nearctic region. Fossil remains of members of this +family have also been found in Europe and America in strata of the Eocene +and early Miocene periods; and it is probable that at least many of the +polyprotodont Mesozoic mammals noticed in Chapter IV. are referable to +the Marsupialia. + +[Illustration: FIG. 36.—Front view of skull of Koala (_Phascolarctus +cinereus_), showing diprotodont and herbivorous dentition (_Quart. Journ. +Geol. Soc._ vol. xxiv. p. 313).] + +_Classification._—In dividing the Marsupials into minor groups, it may +be observed that one of the most obvious distinctive characters among +them is derived from the form and arrangement of the teeth. In certain +species, as the Opossums, Dasyures, and Thylacine, the incisors are +numerous, small, and subequal in size, and the canines large, as in the +typical placental Carnivores (Fig. 35). To these the term “polyprotodont” +is applied, and they are all more or less carnivorous in their habits. +In others the central incisors are very prominent, and the lateral +incisors and canines absent or subordinate in function (Fig. 36). These +are called “diprotodont,” and they are all wholly or in great part +vegetable feeders. In one group of these, the Wombats, there are but two +incisors above and the same number below; but all the others, including +the Kangaroos, Koalas, and Phalangers, have two functional incisors below +and as many as six above, three on each side, but of these the first or +central pair is the most fully developed. + +Some hesitation has frequently been expressed as to whether the +Polyprotodont and Diprotodont types are entitled to constitute distinct +primary groups, owing to the presence of syndactylism among the +_Peramelidæ_ in the former, as well as in the latter; but if Mr. O. +Thomas is right in regarding this feature as acquired independently +in the two groups we may safely adopt such a division. Taking various +combinations into consideration, the existing Marsupials readily group +themselves into six very natural families, the leading characters of +which may be summarised as follows:— + +_Order_ MARSUPIALIA. + +_A._ POLYPROTODONTIA.—Incisors numerous, small, subequal. Canines larger +than the incisors. Molars with sharp cusps. + + α. Incisors ⁵⁄₄. Hind feet with the four outer toes subequal, + distinct, and a well-developed opposable hallux. _Didelphyidæ._ + + β. Incisors ⁴⁄₃. Hind feet with four outer toes distinct. + Hallux small or rudimentary, rarely opposable. _Dasyuridæ._ + + γ. Incisors ⁴⁻⁵⁄₃. Hind feet long and narrow. Fourth toe + larger than the others. Hallux rudimentary or absent. Second + and third toes very slender, and united in a common integument + (syndactylous). _Peramelidæ._ + +_B._ DIPROTODONTIA.—Incisors not exceeding ³⁄₃, usually ³⁄₁ but +occasionally ¹⁄₁. Central (first) upper and lower incisors large and +cutting. Upper canines generally, and lower invariably, absent or small. +Molars with bluntly tuberculated or transversely ridged crowns. + + α. Teeth with persistent pulps. Incisors ¹⁄₁, large, + scalpriform, with enamel on the outer surface only. No + canines. Hind feet with four subequal outer toes, partially + syndactylous, and with rudimentary hallux. _Phascolomyidæ._ + + β. Teeth rooted. Three upper incisors and a canine. Hind + limbs not disproportionately large. Feet syndactylous, broad, + with four subequal outer toes, and a large opposable hallux. + _Phalangeridæ._ + + γ. Teeth rooted. Three upper incisors, and frequently a canine. + Hind limbs disproportionately large, with syndactylous feet as + in _Peramelidæ_. _Macropodidæ._ + + +_Suborder_ POLYPROTODONTIA. + +The leading characters of this group are given in the foregoing schedule. +This group is the only one represented at the present day, and so far +as we know also in past epochs, beyond the confines of the Australasian +region and adjacent islands. + + +_Family_ DIDELPHYIDÆ. + +Dentition: _i_ ⁵⁄₄, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ⁴⁄₄; total 50. Incisors very +small and pointed. Canines large. Premolars with compressed pointed +crowns. Molars with numerous sharp cusps. The last premolar preceded by +a deciduous multicuspidate milk-molar, which remains in place until the +animal is nearly adult (Fig. 34). Limbs of moderate development, each +with five complete and distinct toes, all of which are provided with +short, compressed, curved, sharp claws of nearly equal size, except the +first toe of the hind foot or hallux (Fig. 37), which is large, widely +separable from the others, to which it is opposed in climbing, and +terminates in a dilated rounded extremity, without a nail. Tail generally +long, partially naked and prehensile. Stomach simple. Cæcum of small +or moderate size. Pouch generally absent, sometimes represented by two +lateral folds of the abdominal integument, partially covering the teats, +rarely complete. Vertebræ: C 7, D 13, L 6, S 2, C 19-35. + +[Illustration: FIG. 37.—Skeleton of the right hind foot of the Virginian +Opossum (_Didelphys marsupialis_).] + +The _Didelphyidæ_, or true Opossums, differ from all other existing +Marsupials in their habitat, being peculiar to the American continent. +They are mostly carnivorous or insectivorous in their diet, and arboreal +in habits. + +Opossums occur throughout the greater part of the American continent, +ranging from the United States to Patagonia, the greater number of +species being found in the warmer regions. In South America the opossums +take the place of the Eutherian Insectivora, and the sharp cusps on their +teeth are admirably adapted for crushing the insects on which they mainly +subsist. + +_Chironectes._[40]—The family comprises two genera only, namely +_Didelphys_, containing all the species, with the exception of +the curious Yapock, which forms by itself the genus _Chironectes_ +and is distinguished from all other Opossums by its webbed feet, +non-tuberculated soles, and peculiar coloration. Its ground colour is +light gray, with four or five sharply-contrasted brown bands passing +across its head and back, and thus giving it a very peculiar mottled +appearance. It is almost wholly aquatic in its habits, living on small +fish, crustaceans, and water insects. Its range extends from Guatemala to +southern Brazil. + +_Didelphys._[41]—The type genus _Didelphys_ is a very large one, +containing, according to Mr. O. Thomas, twenty-three existing species. +It may be divided into five groups, or subgenera, all of which have +received distinct names. The typical group is represented only by the +common or Virginian Opossum (_D. marsupialis_), of which the numerous +varieties have received separate specific names. This species is of large +size, with a long, scaly, prehensile tail, and long bristle-like hairs +mingled with the fur. The pouch is complete. It ranges over all temperate +North America, and is also found in central and tropical South America, +where it is commonly known as the Crab-eating Opossum. This animal is +extremely common, being even found living in the towns, where it acts as +a scavenger by night, retiring for shelter by day upon the roofs of the +houses or into the sewers. The female produces in the spring from six +to sixteen young ones, which are placed in her pouch immediately after +birth, and remain there until able to take care of themselves. + +The second or _Metachirine_ group includes three species found all over +the tropical parts of the New World. They are of medium size, with +short close fur, very long, scaly, and naked tails, and less developed +ridges on their skulls than in the type species. As a rule there is no +pouch adapted to carry the young, which commonly ride on their mother’s +back, holding on by winding their prehensile tails round hers. The +_Philanderine_ group is closely allied to the preceding, but is readily +distinguished by the woolly hair, and the brown streak down the middle +of the face. The Woolly Opossum (_D. lanigera_), which is represented +in the accompanying woodcut (Fig. 38) carrying its young in the fashion +mentioned above, is one of the two species of this group. In the fourth +or _Micoureine_ group the numerous species are all smaller than in the +preceding groups, and have short and close hair, and no dark streak down +the face. The best known species is the Murine Opossum (_D. murina_), +little larger than a House-Mouse, and of a bright red colour, which is +found as far north as central Mexico, and extends thence right down +to the south of Brazil. The last or _Peramyne_ group contains several +extremely shrew-like species, of very small size, with short, hairy, +and usually non-prehensile tails, not half the length of the trunk, and +with wholly unridged skulls. The most striking member of the group is +the Three-striped Opossum (_D. americana_), from Brazil, which is of a +reddish-gray colour, with three clearly-defined deep-black bands down its +back, very much as in some of the striped mice of Africa. + +[Illustration: FIG. 38.—The Woolly Opossum (_Didelphys lanigera_).] + +The numerous fossil species of Opossum found in the Upper Eocene and +Lower Miocene of Europe are of especial interest from a distributional +point of view, since they indicate how the Opossums of America may +have been connected with the Australian Marsupials. These forms were +originally referred to _Didelphys_, but have been subsequently described +as _Peratherium_ and _Amphiperatherium_. The characters of the molar +teeth on which these genera are based do not appear to be sufficiently +important to justify their separation from _Didelphys_. Allied forms +occur in the Tertiaries of North America, which were originally described +under the name of _Herpetotherium_, but have been subsequently referred +to _Peratherium_. Remains of many of the existing species of Opossum are +found in a fossil condition in the Pleistocene cave-deposits of Brazil. + + +_Family_ DASYURIDÆ + +Dentition: _i_ ⁴⁄₃, _c_ ¹⁄₁, _p_ and _m_ numerous, variable. Incisors +small; canines well developed; molars with pointed cusps. Limbs equal. +Fore feet with five subequal toes terminating in claws. Hind feet with +the four outer toes well developed, and distinct from each other and +bearing claws; the first (or hallux) clawless, generally rudimentary, +sometimes entirely wanting. Stomach simple. No cæcum. Predatory +carnivorous or insectivorous animals, inhabitants of Australia, Tasmania, +and the southern parts of New Guinea and some of the adjacent islands. +The aberrant genus _Myrmecobius_, though clearly a member of this family, +is so sharply distinguished from all the others as to render a division +into two subfamilies necessary. + +[Illustration: FIG. 39.—The Thylacine (_Thylacinus cynocephalus_).] + +Subfamily =Dasyurinæ=.—This comprises the more typical _Dasyuridæ_, in +which the premolars and molars never exceed the normal number of seven +on either side of each jaw, and in which the tongue is not specially +extensile. + +_Thylacinus._[42]—Dentition: _i_ ⁴⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ⁴⁄₄ = 46. +Incisors small, vertical, the outer one in the upper jaw larger than +the others. Summits of the lower incisors, before they are worn, with a +deep transverse groove dividing them into an anterior and a posterior +cusp. Canines long, strong, and conical. Premolars separated from one +another by intervals, with compressed crowns, increasing in size from +before backwards. True molars in general characters resembling those of +_Dasyurus_, but of more simple form, the cusps being not so distinct nor +sharply pointed. Milk-molar very small, and shed before the animal leaves +the mother’s pouch. Humerus with an entepicondylar foramen. General form +very Dog-like. Head elongated. Muzzle pointed. Ears moderate, erect, +triangular. Fur short and closely applied to the skin. Tail of moderate +length, thick at the base and tapering towards the apex, clothed with +short hair. Hallux (including the metacarpal bone) wanting. Vertebræ: +C 7, D 13, L 6, S 2, C 23. Marsupial bones represented only by small +unossified fibro-cartilages. + +The only known existing species of this genus, _T. cynocephalus_ (Fig. +39), though smaller than a common Wolf, is the largest predaceous +Marsupial at present living. It is now entirely confined to the island +of Tasmania, although fragments of bones and teeth found in caves afford +evidence that a closely allied species once inhabited the Australian +mainland. The general colour of the Thylacine is grayish brown, but +it has a series of transverse black bands on the hinder part of the +back and loins, whence the name of “Tiger” frequently applied to it +by the colonists. It is also called “Wolf,” and sometimes, though +less appropriately, “Hyæna.” Owing to the havoc it commits among the +sheepfolds, it has been nearly exterminated in all the more settled parts +of Tasmania, but still finds shelter in the almost impenetrable rocky +glens of the more mountainous regions of the island. The female produces +four young at a time. The pouch opens backwardly, and there are four +mammæ. The figure of the skull exhibits the peculiar Dog-like form so +characteristic of the genus. + +[Illustration: FIG. 40.—Right lateral aspect of the skull of the +Thylacine.] + +_Sarcophilus._[43]—Dentition: _i_ ⁴⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ⁴⁄₄. +Upper incisors nearly equal, and placed vertically, the first not +differentiated from the rest. Premolars rounded and closely crowded +between the canine and molars, with broad crowns; molars broad and heavy, +the last one without a distinct hind talon. Form thick and powerful; +head disproportionately large for the body; muzzle short and broad; +ears broad and rounded; tail of moderate length, and evenly hairy. +Hallux wanting; soles of feet naked, without defined pads. Humerus with +entepicondylar foramen. + +This genus is now represented only by a single species (_S. ursinus_) +found in Tasmania, where, from its ferocious and destructive habits, it +is commonly known under the name of the “Devil.” A front view of the +skull is shown in Fig. 35. + +The prevailing colour of this animal is black, and the size about equal +to that of an English Badger; its habits are fossorial, and it is very +destructive to sheep. On account of the similarity in the number of its +teeth this genus has been generally included in the next one, but in the +structure of the teeth it is much nearer to _Thylacinus_. An extinct +species is found in the Pleistocene deposits of the mainland of Australia. + +It may be observed that the two premolars missing from the typical +series of four in this and the next genus are the second and the fourth; +the fourth milk-molar being likewise absent. In _Thylacinus_ and other +Polyprotodonts with three premolars it is the second that is missing. + +_Dasyurus._[44]—Dentition: _i_ ⁴⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ⁴⁄₄; total +42. Upper incisors nearly equal, and placed vertically; first slightly +longer, narrower, and separated from the rest. Lower incisors sloping +forwards and upwards. Canines large and sharply pointed. Premolars with +compressed and sharp-pointed crowns, and slightly developed anterior and +posterior accessory basal cusps. True molars with numerous sharp-pointed +cusps. In the upper jaw the first three with crowns having a triangular +oral surface, the fourth small, simple, narrow, and placed transversely. +In the lower jaw the molars more compressed, with longer cusps; the +fourth not notably smaller than the others. Form viverrine. Ears long and +narrow, prominent, and obtusely pointed. Hallux rudimentary, or absent; +its metatarsal bone always present. Tail long and well clothed with hair. +Humerus without an entepicondylar foramen. Vertebræ: C 7, D 13, L 6, S 2, +C 18-20. + +The Dasyures are small Civet-like animals with a gray or brown pellage +profusely spotted with white; they are mostly inhabitants of the +Australian continent and Tasmania, where in the economy of nature they +take the place of the smaller predaceous Carnivora, the Cats, Civets, and +Weasels of other parts of the world. They hide themselves in the daytime +in holes among rocks or in hollow trees, but prowl about at night in +search of the small living mammals and birds which constitute their prey. +The species are not numerous, and include _D. maculatus_, about the size +of a common Cat, inhabiting Tasmania and the southern part of Australia; +_D. viverrinus_, Tasmania and Victoria; _D. geoffroyi_, nearly all +Australia; _D. hallucatus_, North Australia; _D. albopunctatus_, New +Guinea. + +Remains referred to _D. viverrinus_ occur in the Australian Pleistocene +deposits. + +_Phascologale._[45]—This genus comprises a considerable number of small +Marsupials, none of them exceeding a common Rat in size, differing from +the Dasyures in possessing an additional premolar—the dentition being _i_ +⁴⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ⁴⁄₄; total 46,—and having the teeth generally +developed upon an insectivorous rather than a carnivorous pattern, the +upper middle incisors being larger and inclined forwards, the canines +relatively smaller, and the molars with broad crowns, armed with prickly +tubercles. The muzzle is pointed. Ears moderately rounded and nearly +naked. Feet broad and short. Fore feet with five subequal toes, having +compressed, slightly curved, pointed claws. Hind feet with the four outer +toes subequal, having claws similar to those in the fore feet; the hallux +always distinct and partially opposable, though small and nailless. +Tail long, very variable in its covering, being either bushy, crested, +or nearly naked. Pouch represented merely by a few folds of skin. Mammæ +varying from four to ten in number. The food of these animals is almost +entirely insects; some species pursuing their prey among the branches of +trees, while others are purely terrestrial. They are found throughout +Australia, and also in New Guinea and the Aru and some of the adjacent +islands. + +_P. cristicaudata_, a species with a thick compressed tail ornamented +upon its apical half with a crest of black hair, differs from the others +by the very reduced size of the fourth premolar in the upper, and its +complete absence in the lower jaw, thus forming an interesting transition +in dentition towards _Dasyurus_. It constitutes the genus _Chætocercus_ +of Krefft, but is included by Mr. O. Thomas in _Phascologale_, the +frequent absence of the fourth lower premolar in _P. thorbeckiana_ +indicating that the total absence of this tooth in the known specimens of +this species cannot be regarded as of generic importance. All the members +of this and the two following genera can be at once distinguished from +_Dasyurus_ by the absence of white spots on the fur. + +_Sminthopsis._[46]—The genus _Sminthopsis_ includes several small species +allied to _Phascologale_ but characterised by the narrowness of the hind +foot, and by the soles of the feet being either granulated or hairy, +instead of naked. + +_Antechinomys._[47]—The last genus of the _Dasyurinæ_ is _Antechinomys_, +represented only by _A. laniger_ of Queensland and New South Wales. This +elegant little mouse-like creature, which has large oval ears and a long +tail with the terminal part bushy, is distinguished from _Sminthopsis_ +by the absence of the hallux and the great elongation of the limbs. The +tympanic bullæ of the skull are also unusually large, with the mastoid +portion much swollen. A full account of the habits and anatomy of this +animal, which appears to be of very rare occurrence, is given in the +_Proc. Zool. Soc._ 1880, p. 454. + +Subfamily =Myrmecobiinæ=.—Molars and premolars exceeding the normal +number of seven on each side. Tongue, long cylindrical, and extensile. + +[Illustration: FIG. 41.—_Myrmecobius fasciatus._ From Gould.] + +_Myrmecobius._[48]—Dentition: _i_ ⁴⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ⁵⁄₅ or +⁶⁄₆; total 52 or 56, being the largest number of teeth in any existing +Marsupial. The distinction between the molars and premolars is founded +not on a knowledge of the succession of the teeth, but on their form. +The teeth are all small and (except the four posterior inferior molars) +separated from each other by an interval. Head elongated, but broad +behind. Muzzle long and pointed. Ears of moderate size, ovate, and rather +pointed. Fore feet with five toes, all having strong, pointed, compressed +claws, the second, third, and fourth nearly equal, the fifth somewhat, +and the first considerably, shorter. Hind feet with no trace of hallux +externally, but the metatarsal bone present. Tail long, clothed with +long hairs. Fur rather harsh and bristly. Female without any pouch, the +young when attached to the nipples being concealed only by the long hair +of the abdomen. Vertebræ: C 7, D 13, L 6, S 3, C 23. A gland on the under +surface of the body just in advance of the sternum. + +Of this singular genus but one species is known, _M. fasciatus_ (Fig. +41), found in western and southern Australia. It is about the size of +an English squirrel, to which animal its long bushy tail gives it some +resemblance; but it lives entirely on the ground, especially in sterile, +sandy districts, feeding on ants. Its prevailing colour is chestnut red, +but the hinder part of the back is elegantly marked with broad, white, +transverse bands on a dark ground. + +The special interest of this form lies in its apparent relationship to +those Mesozoic mammals which possess a large number of true molars (see +p. 114); and it is suggested by Thomas that it may eventually be found +advisable to include some of the latter in the present subfamily. + + +_Family_ PERAMELIDÆ. + +Dentition: _i_ ⁴⁻⁵⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ⁴⁄₄; total 46 or 48. Upper +incisors small, with short broad crowns. Lower incisors moderate, narrow, +proclivous. Canines well developed. Premolars compressed, pointed. Molars +with quadrate tuberculated crowns. Fourth premolar preceded by a small +molariform tooth, which remains in place until the animal is nearly full +grown. Fore feet with two or three of the middle toes of nearly equal +size, and provided with strong, sharp, slightly curved claws; the other +toes rudimentary. Hind feet long and narrow; the hallux rudimentary or +absent; the second and third toes very slender, and united in a common +integument; the fourth very large, with a stout elongated conical claw; +the fifth smaller than the fourth (see Fig. 43). The ungual phalanges of +the large toes of both feet cleft at their extremities (as in _Manis_ +among the Edentata, but in no other Marsupials). Head elongated. Muzzle +long, narrow, and pointed. Stomach simple. Cæcum of moderate size. +Pouch complete, opening backwards. Alone among Marsupials they have no +clavicles. + +The _Peramelidæ_ form a very distinct family, in some respects +intermediate between the sarcophagous _Dasyuridæ_ and the phytophagous +_Macropodidæ_. In dentition they resemble the former, but they agree +with the latter in the peculiar structure of the hind feet. In the +construction of the fore feet they differ from all other Marsupials. + +The Bandicoots, as these Marsupials are popularly termed, are of +fossorial habits, and subsist either on an insectivorous or omnivorous +diet. It has been generally considered that their syndactylous feet +indicate direct affinity with the Diprotodonts, but owing to the +essentially Polyprotodont character of the organisation—which extends +even to their carpal and tarsal bones—Thomas dissents from this view, and +concludes that their syndactylism is an independently acquired character, +and that they are really a direct offshoot from the _Dasyuridæ_. Some +individuals are remarkable for the presence of a longitudinal groove in +the root of the canines, by which feature they approximate to some of the +Mesozoic Polyprotodont forms. They may be divided into three genera. + +[Illustration: FIG. 42.—_Perameles gunni._ From Gould.] + +_Perameles._[49]—Anterior and posterior extremities not differing greatly +in development. Fore feet with the three middle toes well developed, +the third slightly larger than the second, the fourth somewhat shorter, +provided with long, strong, slightly curved, pointed claws. First and +fifth toes very short and without claws. Hind feet with hallux of one or +two phalanges, forming a distinct tubercle visible externally; the second +and third toes very slender, of equal length, joined as far as the ungual +phalanges, but with distinct claws; the fifth intermediate in length +between these and the largely developed fourth toe. Ears of moderate +or small size, ovate, pointed. Tail rather short, clothed with short +adpressed hairs. Fur short and harsh. Vertebræ; C 7, D 13, L 6, S 1, C +17. Skull long and narrow, with the bulla single, and its mastoid portion +not inflated. + +The animals of this genus are all small, and live entirely on the ground, +making nests composed of dried leaves, grass, and sticks in hollow +places. They are rather mixed feeders; but insects, worms, roots, and +bulbs constitute their ordinary diet. The various species are widely +distributed over Australia, Tasmania, New Guinea, and several of the +adjacent islands, as Aru, Kei, and New Ireland. The best known are—_P. +gunni_ (Fig. 42), _bougainvillei_, _nasuta_, _obesula_, and _macrura_ +from Australia, and _P. doreyana_, _raffrayana_, and _longicaudata_ from +New Guinea. + +Remains apparently referable to existing species are found in the +cave-deposits of New South Wales. + +_Peragale._[50]—Molar teeth curved, typically with longer crowns and +shorter roots than in the last. Hinder extremities proportionally longer, +and hallux without claw. Muzzle much elongated and narrow. Fur soft +and silky. Ears very large, long, and pointed. Tail long, its apical +half clothed on the dorsal surface with long hairs which form a crest. +Vertebræ: C 7, D 13, L 6, S 2, C 23. Skull distinguished from that of +_Perameles_ by the large size and double structure of the auditory +bulla, of which the mastoid portion is inflated. There is also an abrupt +contraction of the muzzle at the third premolar. + +The type species of Rabbit-Bandicoot (_P. lagotis_), as these animals +are called, is found in Western Australia, and also occurs fossil in the +cave-deposits of New South Wales. It is the largest member of the family, +being about the size of the common Rabbit, to which animal it bears +sufficient superficial resemblance to have acquired the name of “Native +Rabbit” from the colonists. It burrows in the ground, but in other +respects resembles the true Bandicoots in its habits. + +The smaller _P. leucura_ has short-crowned molars, with distinct cusps, +which are almost obsolete in the type species. + +[Illustration: FIG. 43.—Skeleton of right hind foot of _Chœropus +castanotis_. _c_, Calcaneum; _a_, astragalus; _cb_, cuboid; _n_, +navicular; _c³_, ectocuneiform; II and III, the conjoined second and +third digits; IV, the large and only functional digit; V, the rudimentary +fifth digit.] + +_Chœropus._[51]—Dentition generally resembling that of _Perameles_, but +the canines are less developed, and in the upper jaw two-rooted. Limbs +very slender; posterior nearly twice the length of the anterior. Fore +feet with the functional toes reduced to two, the second and third, of +equal length, with closely united metacarpals and short, sharp, slightly +curved, compressed claws. First toe represented by a minute rudiment of +a metacarpal bone; the fourth by a metacarpal and two small phalanges +without a claw, and not reaching the middle of the metacarpal of the +third; fifth entirely absent. Hind foot (Fig. 43) long and narrow, +mainly composed of the strongly developed fourth toe, terminating in a +conical pointed nail, with a strong pad behind it; the hallux absent or +represented by a rudimentary metatarsal; the remaining toes completely +developed, and with claws, but exceedingly slender; the united second and +third reaching a little way beyond the metatarso-phalangeal articulation +of the fourth; the fifth somewhat shorter. Tail not quite so long as the +body, and covered with short hairs forming a slight crest. Ears large and +pointed, and folded down when the animal is at rest. Fur soft and loose. +Vertebræ: C 7, D 13, L 6, S 1, C 20. Skull short and wide, with a small +and single bulla, and a contraction of the muzzle at the third premolar. + +The only known species of this genus (Fig. 44), chiefly remarkable for +the singular construction of its limbs, is an animal about the size of a +small Rat, found in the interior of the Australian continent. Its general +habits and food appear to resemble those of the other _Peramelidæ_. +It was first described as _C. ecaudatus_ by Ogilby from a mutilated +specimen, but the specific name was afterwards changed, as being +inappropriate, by Gray to _castanotis_. + + +_Suborder_ DIPROTODONTIA. + +For the leading characters of this group, see page 132. + + +_Family_ PHASCOLOMYIDÆ. + +Dentition: _c_ ¹⁄₁, _i_ ⁰⁄₀, _p_ ¹⁄₁, _m_ ⁴⁄₄ = 24. All the teeth with +persistent pulps. The incisors large, scalpriform, with enamel only +on the front surface, as in the Rodentia. The molars strongly curved, +forming from the base to the summit about a quarter of a circle, the +concavity being directed outwards in the upper and inwards in the +lower teeth. The first of the series, or premolar, appears to have no +milk-predecessor, and is single-lobed; the other four composed of two +lobes, each subtriangular in section. Limbs equal, stout, and short. +Fore feet with five distinct toes, each furnished with a long, strong, +and slightly curved nail, the first and fifth considerably shorter +than the other three. Hind feet with a very short nailless hallux, the +second, third, and fourth toes partially united by integument, of nearly +equal length, the fifth distinct and rather shorter; all four provided +with long and curved nails. In the skeleton of the foot, the second +and third toes are distinctly more slender than the fourth, showing a +slight tendency towards the peculiar character so marked in the next +two families. Tail rudimentary. Stomach simple, provided with a special +gland situated near the cardiac orifice. Cæcum very short, wide, and with +a peculiar vermiform appendage. Pouch present. The auditory bullæ of +the skull are imperfect, open behind, with their anterior wall formed +by a descending process of the squamosal, instead of the alisphenoid. +Masseteric fossa of mandible with a perforation and a deep pit. + +[Illustration: FIG. 44.—_Chœropus castanotis._ From Gould.] + +_Phascolomys._[52]—The existing Wombats (Fig. 45) comprise three +species, all of which are included in the one genus _Phascolomys_, and +all of which date from the Pleistocene. + +In the typical group we find the following characters. Fur rough and +coarse. Ears short and rounded. Muffle naked. Postorbital process of the +frontal bone obsolete. Ribs fifteen pairs. Vertebræ: C 7, D 15, L 4, S +4, C 10-12. The Wombat of Tasmania and the islands of Bass’s Straits +(_P. ursinus_) and the closely similar but larger animal of the southern +portion of the mainland of Australia (_P. mitchelli_) belong to this +group. + +[Illustration: FIG. 45.—Common Wombat (_Phascolomys ursinus_).] + +In the second group the characters are as follows. Fur smooth and silky. +Ears large and more pointed. Muffle hairy. Frontal region of skull +broader than in the other group, with well-marked postorbital processes. +Ribs thirteen. Vertebræ: C 7, D 13, L 6, S 4, C 15-16. One species, _P. +latifrons_, the Hairy-nosed Wombat of Southern Australia. + +In their general form and actions the Wombats resemble small bears, +having a somewhat similar shuffling manner of walking, but they are still +shorter in the legs, and have broader, flatter backs than bears. They +live entirely on the ground, or in burrows or holes among rocks, never +climbing trees, and feed entirely on grass, roots, and other vegetable +substances. They sleep during the day, and wander forth at night in +search of food, and are shy and gentle in their habits generally, though +they can bite strongly when provoked. The only noise the common wombat +makes is a low kind of hissing, but the Hairy-nosed Wombat is said to +emit a short quick grunt when annoyed. The prevailing colour of the +last-named species, as well as of _P. ursinus_ of Tasmania, is a brownish +gray. The large wombat of the mainland is very variable in colour, some +individuals being found of a pale yellowish brown, others dark gray, and +some quite black. The length of head and body is about three feet. + +It is noteworthy that _P. mitchelli_ was first described from the +evidence of fossil remains, the living form subsequently described as _P. +platyrhinus_ being found to be indistinguishable. Other extinct species +occur in the Pleistocene of Australia. + +_Phascolonus._[53]—Remains of a large extinct Wombat, which must have +nearly equalled the dimensions of a Tapir, occur in the Pleistocene of +Queensland, and have been described as _Phascolonus_. It is probable that +the expanded and flattened upper incisors from the same deposits upon +the evidence of which the presumed genus _Sceparnodon_ was founded, are +likewise referable to the same form. The characters of both the upper and +lower incisors distinguish _Phascolonus_ from _Phascolomys_. + + +_Family_ PHALANGERIDÆ. + +Dentition extremely variable, owing to the presence of minute rudimental +teeth not constant in the same species, or even in the two sides of +the jaws of the same individual; exclusive, however, of _Tarsipes_, +the formula _i_ ³⁄₁, _c_ ¹⁄₀, _p_ ²⁻³⁄₀₋₂, _m_ ³⁻⁴⁄₃₋₄ represents +fairly the general condition of the functional teeth. First incisors +long and stout; the lower pair very large and pointed, but without the +scissor-like action found in the existing _Macropodidæ_; second and +third lower incisors minute and probably functionless. Fourth premolar +generally secant; milk-molar generally minute and deciduous at an early +period. Molars either with sharp cutting-crests or bluntly tuberculate; +fourth sometimes absent. Mandible without pit, and at most a very minute +perforation in the masseteric fossa. Limbs subequal. Fore feet with five +distinct, subequal toes, furnished with claws. Hind feet short and broad, +with five well developed toes; the hallux large, nailless and opposable; +the second and third slender, and united by a common integument as far as +the claws. Tail generally long, and frequently more or less prehensile. +Stomach simple. Cæcum present (except in _Tarsipes_), and usually large. +Pouch complete. Animals of small or moderate size and arboreal habits, +usually feeding on a vegetable or mixed diet, inhabiting Australia and +the Papuan Islands. + +The homologies of the lower functionless teeth between the first +incisor and fourth premolar are very difficult to determine, but it is +probable that one represents a canine only when the largest known number +is present; this tooth, according to Mr. Thomas, being the first to +disappear. + +Phalangers are small woolly-coated animals, with long, powerful, and +often prehensile tails, large claws, and, as in the American opossums, +with opposable nailless great toes. Their expression seems in the +day to be dull and sleepy, but by night they appear to decidedly +greater advantage. They live mostly upon fruit, leaves, and blossoms, +although some few feed habitually upon insects, and all relish, when +in confinement, an occasional bird or other small animal. Several of +the Phalangers possess flying membranes stretched between their fore +and hind limbs (Fig. 48), by the help of which they can make long and +sustained leaps through the air, like the Flying Squirrels, but it is +interesting to notice that the possession of these flying membranes +does not seem to be any indication of special affinity, the characters +of the skull and teeth sharply dividing the flying forms, and uniting +them with other species of the non-flying groups. Their skulls (Fig. 47) +are as a rule broad and flattened, with the posterior part swollen out +laterally, owing to the numerous air-cells situated in the substance of +the squamosal. + +The Phalangers are interesting from an historical point of view, since +the Gray Cuscus (_Phalanger orientalis_) was the first of the Marsupials +of the eastern hemisphere brought to the notice of Europeans, having been +described in a work published at Leyden in 1611, from an account of a +specimen seen at Amboyna during the third expedition of Admiral Van der +Hagen. + +The present family corresponds to the _Dasyuridæ_ among the +Polyprotodonts as presenting, on the whole, the most generalised types of +the suborder. The existing forms may be divided into three subfamilies. + +Subfamily =Tarsipedinæ=.—Cheek-teeth almost rudimentary and variable in +number. Tongue long, slender, pointed, and very extensile. Tail long. +Cæcum absent. + +[Illustration: FIG. 46.—_Tarsipes rostratus._ From Gould.] + +_Tarsipes._[54]—So named from some supposed resemblance of its foot to +that of the Lemurine genus _Tarsius_; but it must be remarked that it +has none of the peculiar elongation of the calcaneum and navicular so +characteristic of that genus. Head with elongated and slender muzzle. +Mouth-opening small. The two lower incisors are long, very slender, +sharp-pointed, and horizontally placed. All the other teeth are simple, +conical, minute, and placed at considerable and irregular intervals +apart in the jaws, the number appearing to vary in different individuals +and even on different sides of the same individual. The formula, in a +specimen in the Museum of the Royal College of Surgeons, is _i_ ²⁄₁, +_c_ ¹⁄₀, _p_ and _m_ ³⁄₂ on one side, and ⁴⁄₃ on the other; total 20. +Rami of the mandible extremely slender, nearly straight, and without +coronoid process or inflected angle. Fore feet with five well-developed +toes, furnished with small, flat, scale-like nails, not reaching to the +extremity of the digits. Hind feet rather long and slender compared +with those of the _Phalangerinæ_, having a well-developed opposable +and nailless hallux; second and third digits syndactylous, with sharp +compressed curved claws; the fourth and fifth free, and with small flat +nails. Ears of moderate size and rounded. Tail longer than the body and +head, scantily clothed with short hairs, prehensile. Vertebræ: C 7, D 13, +L 5, S 3, C 24. + +Of this singular genus but one species, _T. rostratus_ (Fig. 46), is +known, about the size of a common Mouse. It inhabits Western Australia, +lives in trees and bushes, uses its tail in climbing, and feeds on honey, +which it procures by inserting its long tongue into the blossoms of +_Melaleucæ_, etc. One kept in confinement by Mr. Gould was also observed +to eat flies. + +Subfamily =Phalangerinæ=.—Teeth normal. One or more rudimentary teeth +between the upper canine and fourth premolar, and between the first +lower incisor and fourth premolar. Tongue of ordinary structure. No +cheek-pouches. Stomach and ascending colon simple. Cæcum long, simple. +Tail well-developed, generally prehensile. + +A numerous group of animals, varying from the size of a mouse to that +of a large cat, arboreal in their habits, and abundantly distributed +throughout the Australian region. The members of this group are the +typical representatives of the family, and are commonly known to the +colonists as Opossums. + +_Phalanger._[55]—The typical genus _Phalanger_ (_Cuscus_) presents the +following characters. No flying membrane; size large or medium, and +build stout and clumsy; fur thick and woolly. Ears short or medium, +hairy externally, and in some cases also internally. Toes of fore feet +subequal, their relative lengths in the order 4, 3, 5, 2, 1. Claws +long, stout, and curved. Soles of feet naked and striated, with large +ill-defined pads. Tail stout and markedly prehensile, with the proximal +half furred like the body, and the terminal portion entirely naked. Four +mammæ. Skull (Fig. 47) stout and strong, with large vacuities in the +hinder half of the palate, and the auditory bullæ thick and inflated. +Dentition usually _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ³⁄₃, _m_ ⁴⁄₄. First upper incisor +with nearly circular section, or only slightly flattened in front; canine +more or less closely approximated to third incisor (which is very small), +and situated partly in front of the suture between the premaxilla and +maxilla. Fourth premolar large, secant, and placed obliquely to line +of molars. Molars four-cusped, with the inner cusps of the upper ones +crescentoid, and imperfect transverse ridges connecting each pair of +cusps. + +[Illustration: FIG. 47.—Left lateral view of skull of Gray Cuscus +(_Phalanger orientalis_). After Peters.] + +The Cuscuses are curious sleepy-looking animals, inhabiting the various +islands of the East Indian Archipelago as far west as Celebes, and +being the only Marsupials found west of New Guinea. As already noted, +it was a member of this genus, the Gray Cuscus (_P. orientalis_), a +native of Amboyna, Timor, and the neighbouring islands, which was the +first Australasian Marsupial known to European naturalists. There are +altogether five species known, all of about the size of a large cat; +their habits resemble those of other Phalangers, except that they are +said to be somewhat more carnivorous. + +_Trichosurus._[56]—The members of the genus _Trichosurus_ are of +relatively large size, and are distinguished from _Phalanger_ by the +following characters. Ears more or less hairy behind. Relative lengths of +toes of fore feet in the order 4, 3, 2, 5, 1. Hair on the soles of the +hind feet beneath the heel, but not elsewhere. Tail thick, not tapering, +covered with bushy hair up to the extreme tip, which is naked, but with a +naked strip on the inferior surface in the distal third or half. A gland +on the chest. Dentition usually _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ²⁄₂, _m_ ⁴⁄₄. Upper +incisors of nearly uniform length, the first much flattened in front. +Canine situated some distance behind the third upper incisor, which it +scarcely exceeds in size. Last premolar and molars very similar to those +of _Phalanger_. + +The true Phalangers comprise two species, of which the best known is the +Vulpine Phalanger (_T. vulpecula_), so common in zoological gardens, +where, however, it is seldom seen, owing to its nocturnal habits. It is +of about the size and general build of a small fox, whence its name. In +the typical variety the colour is gray, with a yellowish white belly, +white ears, and a black tail. This variety is a native of the greater +part of the continent of Australia, but is replaced in Tasmania by the +closely allied Brown Phalanger (_var. fuliginosa_). Its habits are very +similar to those of the Yellow-bellied Flying-Phalanger (_Petaurus +australis_) described below, except that it is unable to take the flying +leaps of that animal. Like all the other phalangers, its flesh is freely +eaten both by the natives and the lower class of settlers. + +_Pseudochirus._[57]—The genus _Pseudochirus_ agrees with the preceding +in the absence of a flying membrane, and presents the following leading +characters. Size large or medium. Fur comparatively short and woolly. +Ears medium or short, hairy behind, although seldom closely furred +over all this aspect. Claws medium. Fore toes subequal, the first two +distinctly opposable to the other three. Soles of feet naked, with large, +striated, round pads, and hair beneath the heels. Tail tapering, markedly +prehensile, with its distal third and the whole of the under surface +short-haired; tip naked underneath for a short distance. Four mammæ. No +gland on chest. Skull with larger nasals than in the preceding genera; +the posterior part of the palate in most cases fully ossified, and the +auditory bullæ generally somewhat inflated. Dentition (at most) _i_ +²⁻³⁄₂, _c_ ⁰⁻¹⁄₀, _p_ ³⁄₃, _m_ ⁴⁄₄. Upper teeth nearly uniform in length, +but the first incisor distinctly longer than second. Upper premolars +variable. Molars with both inner and outer cusps distinctly crescentoid, +and recalling those of the Selenodont Artiodactyle Ungulates. + +_Range._—Tasmania, Australia, and New Guinea. + +There are about ten species of this genus known, of which the commonest +is Cook’s Ring-tailed Phalanger (_Pseudochirus peregrinus_), an animal +discovered by Captain Cook during his first voyage, at Endeavour river, +North Queensland. + +The complex and sub-selenodont character of the molars of this and +the following genus readily distinguish them from the more typical +Phalangers, and show an approximation to the type of dentition prevailing +in _Phascolarctus_; according, however, to Mr. O. Thomas, a tendency +towards the same structure is observable in unworn molars of young +Cuscuses. The genus may be divided into three groups, of which the first, +as typified by the common _P. peregrinus_, is restricted to Australia +and Tasmania, while the third, as represented by _P. canescens_, is only +found in New Guinea. _P. albertisi_ may be taken as the type of the +second group, which is represented by that species in New Guinea, and by +_P. archeri_ in Queensland. With the exception of _P. peregrinus_, the +species have a more or less restricted range. Remains of _Pseudochirus_, +probably referable to existing species, are found in the cave-deposits of +New South Wales. + +_Petauroides._[58]—With the genus _Petauroides_, containing only +the single species _P. volans_, we come to the first of the +Flying-Phalangers, characterised by the possession of a living membrane +along the flanks. The characters of this genus are as follows. Size +large. Fur very long and silky. Ears large and oval, thickly furred on +the back, but naked internally. Flying-membrane reaching from wrist to +ankle, but very narrow along the sides of the forearm and lower leg. +Fore toes subequal, their relative lengths in the order 4, 3, 5, 2, 1. +Claws long, curved, and sharp. Tail long, cylindrical, and bushy, except +near its tip, where it is naked and prehensile. Skull short and broad, +with the nasals short, and not extending nearly as far forwards as the +premaxillæ. Large vacuities in hinder part of palate. Auditory bullæ +inflated and smooth. Dentition usually _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ²⁄₂, _m_ +⁴⁄₄. General characters of teeth very similar to those of _Pseudochirus_, +but the first upper incisor scarcely longer than the second. + +The single species is found in Australia, from Queensland to Victoria, +and is commonly known as the Taguan Flying-Phalanger. The structure +of the skull and teeth indicates close affinity with _Pseudochirus_, +although the external form is widely different in the two genera. +This Phalanger seems, indeed, to be, so to speak, a very specialised +_Pseudochirus_, in which the teeth have become somewhat further +diminished and the flying membrane has been developed. + +_Dactylopsila._[59]—The genus _Dactylopsila_ is one of the forms without +any trace of a flying membrane, its characters being as follows. Size +medium. Body striped black and white. Ears oval, nearly naked at the +ends. Fore toes of very unequal length, the fourth being enormously +elongated; fourth and fifth toes of pes also markedly elongated. Claws +long, moderately curved. Tail long, cylindrical, and evenly bushy, with +the extremity more or less naked below. Skull narrow, but with the +zygomatic arches greatly expanded; palate fully ossified. Dentition: _i_ +³⁄₃, _c_ ¹⁄₀, _p_ ³⁄₂, _m_ ⁴⁄₄. Upper incisors very large, the third +being directed horizontally forwards; canine small and approximated to +the third incisor, which it resembles. The fourth premolar of moderate +size, with its longer axis placed obliquely. First lower incisor longer +than in any other genus. Molars oblong, with four cusps. + +The typical _D. trivirgata_, or Striped Phalanger, inhabits the Papuan +and North Australian sub-region; a second species (_D. palpator_), +characterised by the still greater elongation of the fourth finger, +occurring in South New Guinea. These animals are said to be of +insectivorous habits, the elongated fourth finger, as in the analogous +instance of the Lemuroid genus _Chiromys_, being apparently specially +adapted for extracting insects and larvæ from their hiding places. + +_Petaurus._[60]—Size medium or small. Fur very soft and silky. A broad +flying membrane extending from the outer side of the fifth digit of the +manus to the ankle. Fore toes usually increasing regularly in length from +the first to the fifth, but in some of the smaller species the fourth +is the longest. Claws strong, sharp, and much curved. Tail long, evenly +bushy to the extremity. Glands on the chest and between the ears. Skull +short and wide, with the nasals expanded posteriorly, and usually two +small palatal vacuities near the second molars. Auditory bullæ inflated, +and variable in size. Dentition: _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ³⁄₃, _m_ ⁴⁄₄. +First upper incisors very large, and taller than canine. Molars with +square crowns rounded at the angles, and four cusps, except in the last, +which is triangular. + +This genus, which ranges from New Ireland to South Australia, but is +not found in Tasmania, contains three species, the largest of which is +the Yellow-bellied Flying-Phalanger (_P. australis_), whose habits are +recorded by Mr. Gould as follows. “This animal is common in all the +brushes of New South Wales, particularly those which stretch along the +coast from Port Philip to Moreton Bay. In these vast forests trees of one +kind or another are perpetually flowering, and thus offer a never-failing +supply of the blossoms upon which it feeds; the flowers of the various +kinds of gums, some of which are of great magnitude, are the principal +favourites. Like the rest of the genus, it is nocturnal in its habits, +dwelling in holes and in the spouts of the larger branches during the +day, and displaying the greatest activity at night while running over +the small leafy branches, frequently even to their very extremities, +in search of insects and the honey of the newly-opened blossoms. Its +structure being ill adapted for terrestrial habits, it seldom descends +to the ground except for the purpose of passing to a tree too distant +to be reached by flight. When chased, or forced to flight it ascends to +the highest branch and performs the most enormous leaps, sweeping from +tree to tree with wonderful address; a slight elevation gives its body an +impetus which, with the expansion of its membrane, enables it to pass to +a considerable distance, always ascending a little at the extremity of +the leap; by this ascent the animal is prevented from receiving the shock +which it would otherwise sustain.” + +A second species, _P. sciureus_, in some ways one of the most beautiful +of all mammals, has been chosen for the accompanying woodcut. + +_Gymnobelideus._[61]—Like _Petaurus_ in every respect, but without +any trace of a flying membrane, and with the fifth digit of the manus +slightly shorter than the third. This genus is represented only by _G. +leadbeateri_ of Victoria, and according to Mr. Thomas, may be regarded +as the primitive form from which the specialised _Petaurus_ has been +developed. + +[Illustration: FIG. 48.—Squirrel Flying-Phalanger (_Petaurus sciureus_).] + +_Dromicia._[62]—Size small, and general appearance dormouse-like. Ears +large and thin, almost naked, and without internal or basal tufts. No +flying membrane. Digits of normal proportions, the relative lengths of +those of the manus in the order 3, 4, 2, 5, 1; fore claws rudimentary, +hind ones long and sharp. Tail mouse-like, cylindrical, furry at base, +the remainder scaly, with fine hairs, except at the tip, which is naked +and prehensile. Skull short and broad, with the hinder part of the +palate incomplete, and the auditory bullæ large, much inflated, and +transparent. Dentition: _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ³⁄₃, _m_ ³⁻⁴⁄₃₋₄. First +upper incisor spatulate, and much longer than either of the others. +Canine large, placed at some distance behind the third incisor. Molars +(except the last) with evenly rounded crowns, carrying four small smooth +cusps. + +This genus, which occurs in New Guinea, Western Australia, and Tasmania, +is represented by four species. It seems to be intermediate between +_Petaurus_ and _Acrobates_, and it has apparently had to yield place to +those more highly organised types in regions where they have come in +contact with one another. + +_Distœchurus._[63]—Size small. Ears rather short, thinly covered with +hair, but with small tufts at the base. No flying membrane. Digits of +normal proportions, without expanded terminal pads. Claws curved and +sharp. Tail, skull, and dentition as in _Acrobates_, with the exception +that the fourth premolar is small in the upper, and absent in the lower +jaw. + +The one species of Feather-tailed Phalanger (_D. pennatus_) is found in +New Guinea. + +_Acrobates._[64]—Size very small. Ears moderate, thinly covered +with hair, but with small tufts round the base and on the internal +prominences. A narrow flying membrane, fringed with long hairs, running +from the elbow to the flank, and from the latter to the knee. Four +mammæ. Digits furnished with expanded and striated terminal pads, the +relative length of those of the manus being in the order 4, 3, 5, 2, +1. Claws sharp, although somewhat concealed by the terminal pads. Tail +short-haired above and below, with a broad fringe on either side. Skull +short, wide, and depressed. Posterior portion of palate very imperfectly +ossified; anterior palatal vacuities almost confined to the maxillæ. +Auditory bullæ low, rounded, and but slightly prominent. Dentition: _i_ +³⁄₂, _c_ ¹⁄₀, _p_ ³⁄₃, _m_ ³⁄₃. Teeth sharp, and of an insectivorous +type. Upper canine long, and approximated to third incisor. The three +upper premolars large, functional, and taller than the molars. Molars +small and rounded, with smooth unridged cusps. + +There is only one species in this genus, the beautiful little Pigmy +Flying-Phalanger (_A. pygmæus_), not so big as a Mouse, which is found +in Queensland, New South Wales, and Victoria, and feeds on the honey +it abstracts from flowers, and on insects. Its agility and powers of +leaping are exceedingly great, and it is said by Mr. Gould to make a most +charming little pet. + +Subfamily =Phascolarctinæ=.—Teeth large, normal; no rudimentary premolars +before the last upper premolar, or any teeth between the first lower +incisor and fourth premolar. Tongue of ordinary structure. Distinct +cheek-pouches. Stomach with a special gland near the cardiac orifice. +Cæcum very long, and (with the upper portion of the colon) dilated and +provided with numerous longitudinal folds of mucous membrane. In many +anatomical characters, especially the possession of a special gastric +gland, this group resembles the _Phascolomyidæ_.[65] + +[Illustration: FIG. 49.—Skeleton of right hind foot of Koala +(_Phascolarctus cinereus_), showing the stout opposable hallux, followed +by two slender toes, which in the living animal are enclosed as far as +the nails in a common integument.] + +_Phascolarctus._[66]—Dentition: _i_ ³⁄₁, _c_ ¹⁄₀, _p_ ¹⁄₁, _m_ ⁴⁄₄; total +30. Upper incisors crowded together, cylindroidal, the first much larger +than the others, with a bevelled cutting edge (Fig. 36). Canine very +small; a considerable interval between it and the premolar, which is as +long from before backwards but not so broad as the true molars, and has +a cutting edge, with a smaller parallel inner ridge. The molars slightly +diminishing in size from the first to the fourth, with square crowns, +each bearing four pyramidal cusps, with curved ridges radiating from +them, and having a structure very similar to these of _Pseudochirus_. The +lower incisors are semiproclivous, compressed and tapering, bevelled at +the ends. Premolars and molars in continuous series, as in the upper jaw. +Milk-tooth very minute, and almost functionless. Fore feet with the two +inner toes slightly separated from and opposable to the remaining three, +all with strong, curved, and much compressed claws. Hind foot (Fig. 49) +with the hallux placed very far back, large and broad, the second and +third (united) toes considerably smaller than the other two; the fourth +the largest. No external tail. Fur dense and woolly. Ears of moderate +size, thickly clothed with long hairs. Vertebræ: C 7, D 11, L 8, S 2, C +8. Ribs eleven pairs, a rare exception to the usual number (13) in the +Marsupialia. + +There is but one species, the Koala or Native Bear of the Australian +colonists (_P. cinereus_), an animal of comparatively large size and +heavy build (Fig. 50), found in the south-eastern parts of the Australian +continent. It is about two feet in length, and of an ash-gray colour, an +excellent climber, and residing generally in lofty _Eucalyptus_ trees, +on the buds and tender shoots of which it feeds, though occasionally +descending to the ground in the night. + + +EXTINCT PHALANGEROIDS. + +Numerous imperfect remains recently described by De Vis are regarded as +indicating large extinct types of _Phalangeridæ_, but further evidence +is required before all these determinations can be definitely accepted. +Thus part of an upper jaw is provisionally referred to a large species +of _Pseudochirus_, while part of a scapula is made the type of a genus +_Archizonurus_ which appears to be allied to the former. Another +fragmentary scapula is considered to indicate a large _Phalanger_. +Finally, part of a fibula, described under the name of _Koalemus_ is +regarded as affording evidence of the former existence of a large +ancestral form allied to the Koala, and it is suggested that an upper jaw +with teeth may belong to the same or an allied type. + +[Illustration: FIG. 50.—The Koala (_Phascolarctus cinereus_). From +Sclater, _Proc. Zool. Soc._ 1880, p. 355.] + +_Thylacoleo._[67]—Dentition of adult: _i_ ³⁄₁, _c_ ¹⁄₀, _p_ ³⁄₃, _m_ ¹⁄₂; +total 28. First upper incisor much larger than the others; canine and +first two premolars rudimentary. In the lower jaw the two small anterior +premolars are functionless, and often deciduous; posterior premolars of +both jaws formed on the same type as those of _Potorous_, but relatively +much larger; true molars rudimentary, tubercular. One species, _T. +carnifex_. This animal presents a most anomalous condition of dentition, +the functional teeth being reduced to one pair of large cutting incisors +situated close to the median line, and one great, trenchant, compressed +premolar, on each side above and below. It was first described as a +carnivorous Marsupial, and named, in accordance with its presumed habits, +“as one of the fellest and most destructive of predatory beasts”; but, as +its affinities are certainly with the _Phalangeridæ_ and _Macropodidæ_, +and its dentition completely unlike that of any known predaceous animal, +this view has been called in question. + +[Illustration: FIG. 51.—Front view of skull of _Thylacoleo carnifex_, +restored. ¹⁄₃ natural size. From _Quart. Journ. Geol. Soc._ vol. xxiv. p. +312.] + +The dentition is nearer to that of the existing _Phalangeridæ_ than to +that of the _Macropodidæ_, and the genus may be provisionally regarded as +the type of a distinct subfamily of the former. + + +_Family_ MACROPODIDÆ. + +Dentition _i_ ³⁄₁, _c_ ⁰⁻¹⁄₀, _p_ ²⁄₂, _m_ ⁴⁄₄. Incisors sharp and +cutting, those of the lower jaw frequently having a scissor-like action +against one another; upper canine, if present, small. Penultimate +premolar shed with the fourth milk-molar, which is molariform and long +persistent. Molars wide, and either transversely ridged or bluntly +tuberculate. Premolars and molars moving forwards in the skull as the age +of the animal increases, this being most marked in the larger species. +Masseteric fossa of mandible hollowed out below into a deep cavity walled +in externally by a plate of bone, and communicating with the inferior +dental canal by a large foramen. Hind limbs usually larger than the +anterior ones, and progression generally saltatorial. Fore feet with five +digits; hind feet syndactylous, the fourth digit being very large and +strongly clawed; hallux usually absent. Tail generally long and hairy, +occasionally prehensile; stomach sacculated. Pouch large and opening +forwards. + +[Illustration: FIG. 52.—Skeleton of right hind foot of Kangaroo.] + +The _Macropodidæ_ or Kangaroos, taken as a whole, form a very well-marked +family, easily distinguished from the other members of the suborder by +their general conformation, and by peculiarities in the structure of +their limbs, teeth, and other organs. They vary in size from that of a +sheep down to a small rabbit. The head, especially in the larger species, +is small, compared with the rest of the body, and tapers forward to the +muzzle. The shoulders and fore limbs are feebly developed, and the hind +limbs usually of disproportionate strength and magnitude, which gives +them a peculiarly awkward appearance when moving about on all fours, +as they occasionally do when feeding. Rapid progression is, however, +performed only by the powerful hind limbs, the animal covering the ground +by a series of immense bounds, during which the fore part of the body is +inclined forwards, and balanced by the long, strong, and tapering tail, +which is carried horizontally backwards. When not moving they often +assume a perfectly upright position, the tail aiding the two hind legs +to form a sort of supporting tripod, and the front limbs dangling by +the side of the chest. This position gives full scope for the senses of +sight, hearing, and smell to warn of the approach of enemies, from which +these animals save themselves by their bounding flight. The fore paws +have live distinct digits, each armed with a strong curved claw. + +The hind foot (Fig. 52), as being a typical example of the syndactylous +modification, may be noticed in some detail. It is extremely long and +narrow, and (with only one exception) without any hallux or great toe. +It consists mainly of one very large and strong toe, corresponding to +the fourth of the human or other typically developed foot, ending in a +strong, curved, and pointed claw. Close to the outer side of this lies +a smaller fifth digit, and to the inner side two excessively slender +toes (the second and third), bound together almost to the extremity in +a common integument. The two little claws of these toes, projecting +together from the skin, may be of use in scratching and cleaning the fur +of the animal, but the toes themselves must have quite lost all connexion +with the functions of support or progression. + +The dentition of the Kangaroos, functionally considered, consists of +sharp-edged incisors, most fully developed near the median line of the +mouth, for the purpose of cropping the various kinds of herbage on which +they feed, and ridged and tuberculated molars for crushing it, there +being no tusks or canines for offensive or defensive purposes. + +The number of vertebræ is—in the cervical region 7, dorsal 13, lumbar +6, sacral 2, caudal varying according to the length of the tail, but +generally from 21 to 25. In the fore limb the clavicle and the radius and +ulna are well developed, allowing of considerable freedom of motion of +the hand. The pelvis has large epipubic or “marsupial” bones. The femur +is short, and the tibia and fibula are of great length, as is the foot, +the whole of which is applied to the ground when the animal is at rest in +the upright position. + +[Illustration: FIG. 53.—The Great Gray Kangaroo (_Macropus giganteus_).] + +The stomach is of large size, and very complex, its walls being puckered +up by longitudinal muscular bands into a great number of sacculi, like +those of the human colon. The alimentary canal is long, and the cæcum +well developed. All the species have a marsupium or pouch formed by a +fold of the skin of the abdomen, covering the mammary glands with their +four nipples. In this pouch the young are placed as soon as they are +born; there their growth and development proceeds; and to it they resort +temporarily for the purpose of shelter, concealment, or transport, for +some time after they are able to run and jump about the ground and feed +upon the same herbage which forms the nourishment of the parent. During +the early period of their sojourn in the pouch, the blind, naked, +helpless young creatures (which in the Great Kangaroo [Fig. 53] scarcely +exceed an inch in length) are attached by their mouths to the nipples +of the mother, and are fed by milk injected into their stomach by the +contraction of the muscle covering the mammary gland. + +The Kangaroos are all vegetable feeders, browsing on grass and various +kinds of herbage, the smaller species also eating roots. They are +naturally timid, inoffensive creatures; but the larger ones when hard +pressed will turn and defend themselves, sometimes killing a dog by +grasping it in their fore paws, and inflicting terrible wounds with the +sharp claws of their powerful hind legs, sustaining themselves meanwhile +upon the tail. A few aberrant forms are arboreal. The great majority are +inhabitants of Australia and Tasmania, forming one of the most prominent +and characteristic features of the fauna of these lands, and in the +scenery of the country, as well as the economy of nature, performing the +part of the deer and antelopes of other parts of the world, which are +entirely wanting in Australia. Kangaroos were very important sources of +food-supply to the natives, and are hunted by the colonists, both for +sport and with a view to their destruction, on account of the damage they +naturally do in consuming the grass, now required for feeding cattle and +sheep. Notwithstanding this, they have in some districts increased in +numbers, owing to the suppression of their former enemies, the aborigines +and the Dingo or native dog. A few species are found in New Guinea and +the adjacent islands, which belong, in the zoological sense, to the +Australian region. + +Before noticing the various generic types of the _Macropodidæ_, a few +words are necessary in respect of the tooth-change, and we may here quote +the observations of Mr. O. Thomas on this subject. “The full dentition +of the members of this family consists, in the upper jaw, first of three +incisors, then of a small canine (often, however, suppressed, as in Fig. +55), and then of six cheek-teeth, of which the second in the series is +the only one which has a milk or deciduous predecessor, and is therefore +the one to be regarded as the last premolar of the typical mammalian +dentition. The special characteristics that render the development and +succession of the teeth in the _Macropodidæ_, and especially in the genus +_Macropus_, so puzzling to systematic zoologists, are: firstly, a general +progression forwards in the jaw of the whole tooth-row, comparable to +that found elsewhere only in the Elephants and some Sirenians; and, +secondly, the fact that before the tooth-change the first tooth of the +series (_p_ 3) and the single milk-tooth (_dm_ 4) placed next to it, +both of which fall out at the change, are respectively so very similar +in shape and size to the first and second teeth of the permanent series, +viz. the permanent premolar (_p_ 4) and the first molar (_m_ 1), as +to be most naturally mistaken for, or compared with, them in specific +descriptions.... The necessary knowledge as to the stage of dentition in +which any skull may be, can often be gained only by cutting open the bone +either above and behind the first tooth of the series to see if the true +permanent _p_ 4 be still buried there (in which case, of course, that +first tooth is only _p_ 3), or behind the last visible molar to see if +there be yet another tooth behind it, showing it to be _m_ 3 and not _m_ +4. The first plan is, as a rule, the better, since _p_ 4 is generally by +far the most important tooth for diagnostic purposes, and its characters +have, therefore, in any case to be taken into account.” + +The _Macropodidæ_ are divided into three well-marked sections: (1) +the true Kangaroos (_Macropodinæ_); (2) a group consisting of smaller +animals, commonly called Rat Kangaroos, or (improperly) “Kangaroo Rats,” +or sometimes Potoroos; and (3) the _Hypsiprymnodontinæ_, now represented +only by a single species. + +Subfamily =Hypsiprymnodontinæ=.—Size very small. Claws small, feeble, +and subequal. Hind feet with an opposable hallux. Tail naked and scaly. +The fourth premolar twisted obliquely outwards, as in _Phalanger_. Other +teeth as in the _Potoroinæ_. + +This subfamily is now represented only by the genus _Hypsiprymnodon_,[68] +which is a form of great interest, as showing a structure of foot +connecting that of the Kangaroos with that of the Phalangers. The +single known species, _H. moschatus_, was described by Ramsay from +specimens discovered in north-east Australia. It was described almost +simultaneously by Owen under the name of _Pleopus nudicaudatus_. From +the resemblance in the structure of the foot and the obliquity of the +premolars to the Phalangers Mr. Thomas has some hesitation as to which +family should receive this genus, but the macropine characters of the +mandible preponderate in favour of the _Macropodidæ_. + +_Triclis._[69]—A lower jaw of a much larger form from the Pleistocene +deposits of Australia apparently indicates another member of this +subfamily, having the outwardly directed and grooved premolar +characteristic of _Hypsiprymnodon_. It differs, however, from that genus, +and also from all other known _Macropodidæ_, in having a small tooth +between the incisor and fourth premolar, which apparently represents a +canine, or perhaps an anterior premolar. This form indicates, therefore, +a closer connexion between the _Phalangeridæ_ and _Macropodidæ_ than any +other. + +Subfamily =Potoroinæ=.—The second section or subfamily, the _Potoroinæ_, +have the first upper incisor narrow, curved, and much exceeding the +others in length (Fig. 54). Upper canines always persistent, flattened, +blunt, and slightly curved. Premolars of both jaws always having large, +simple, compressed crowns, with a nearly straight or slightly concave +free cutting edge, both outer and inner surfaces usually marked by a +series of parallel, vertical grooves and ridges, these teeth being either +set in the same line with the molars, or slightly bent outwards. Molars +with quadrate crowns, having a blunt, conical cusp at each corner, +the fourth notably smaller than the third, sometimes rudimentary, and +appearing early. Fore feet narrow; three middle toes considerably +exceeding the first and fifth in length; their claws long, compressed, +and but slightly curved. Hind feet as in _Macropus_. Tail long and hairy, +sometimes partially prehensile, being used for carrying bundles of grass +with which these animals build their nests. + +[Illustration: FIG. 54.—Skull and teeth of Rat Kangaroo (_Bettongia +lesueuiri_). _c_, Upper canine. The other letters as in Fig. 51.] + +The Potoroos or Rat Kangaroos are all small animals, none of them +exceeding a common rabbit in size. They inhabit Australia and Tasmania, +are nocturnal, and feed on the leaves of various kinds of grasses and +other plants, as well as roots and bulbs, which they dig up with their +fore paws. Nine species are known, presenting a considerable range of +diversity in minor characters, and admitting of being grouped in four +principal sections, which may be allowed the rank of genera. These are: + +_Potorous._[70]—Head long and slender. Auditory bullæ somewhat inflated. +Ridges on premolars few and perpendicular. Large palatine foramina. +Tarsus short. Muffle naked. Three species, viz. _P. tridactylus_, _P. +gilberti_, and _P. platyops_; the last two being confined to West +Australia. + +_Bettongia._[71]—Head comparatively short and broad. Ears short and +rounded. Auditory bullæ generally much inflated. Large palatine foramina. +Tarsus long. Ridges on premolars numerous and oblique. Tail more or less +prehensile, thickly haired, and the hairs on the upper surface longer +than those on the lower, and forming a crest. Muffle naked. Four species, +viz. _B. penicillata_, _B. cuniculus_, _B. gaimardi_, _B. lesueuiri_. + +_Caloprymnus._[72]—Muffle naked, as in _Bettongia_, but the edge of +the hairy part less emarginate backwards in the middle line. Ears +short, rounded, and hairy. Auditory bullæ much inflated, and of large +size. Nasals larger and wider behind than in the other genera. Very +long anterior palatine foramina. Limbs as in _Bettongia_. Tail thin, +cylindrical, evenly coated with short hair, without trace of a crest. +Skull broad and flat, with a remarkably short and conical muzzle. The +sole representative of this genus is _C. campestris_ of South Australia, +originally referred to _Bettongia_. + +[Illustration: FIG. 55.—Skull and Teeth of the Red-necked Wallaby +(_Macropus ruficollis_). _i¹_, _i²_, _i³_, First, second, and third upper +incisors; _pm_, fourth or posterior premolar (the penultimate or third +having been already shed); _m¹_, _m²_, _m³_, _m⁴_, the four true molars. +The last, not fully developed, is nearly concealed by the ascending ramus +of the jaw.] + +_Æpyprymnus._[73]—Head short and broad. Auditory bullæ not inflated. +No palatine foramina. Tarsus long. Muffle partially hairy. Tail +evenly hairy, not crested above. Molars oblong, less distinctly +quadritubercular, and not decreasing so much in size posteriorly as in +the other genera. Represented only by _Æ. rufescens_. + +Remains of _Æ. rufescens_ occur in the Pleistocene cave-deposits of New +South Wales. + +Subfamily =Macropodinæ=.—This subfamily includes the largest forms. +The cutting edges of the upper incisors are nearly level, or the first +pair but slightly longer than the others (Fig. 55). The canines are +rudimentary and often wanting. The premolars are usually not longer +(from before backwards) than the true molars and less compressed than +in the last subfamily; they are placed in precisely the same line with +the molars. The crowns of the molars always have two prominent transverse +ridges; and these teeth increase in size from before backwards, the +fourth molar appearing very late. The fore limbs are small, with subequal +toes armed with strong, moderately long, curved claws. Hind limbs very +long and strongly made. Head small, with more or less elongated muzzle. +Ears generally rather long and ovate. + +Upwards of forty-four existing species of this group have been described, +and many attempts have been made to subdivide them into smaller groups or +genera for the convenience of arrangement and description, but these have +generally been based upon such trivial characters that it is preferable +to speak of many of them as sections of the genus _Macropus_, reserving +generic rank only to forms somewhat aberrant in structure. According to +this arrangement the genera will be as follows: + +_Lagostrophus._[74]—Represented only by the Banded Wallaby (_L. +fasciatus_) of Western Australia, which presents the following +distinctive features. Size small. Muffle naked. Hind feet covered with +long bristly hairs, concealing the claws. Lower part of back marked +by dark cross-bands. Skull with a narrow pointed muzzle and inflated +auditory bullæ; symphysis of mandible firmly united. No canine. Upper +incisive series meeting at a sharp angle, and diverging but slightly +behind. First incisor smaller in section than either of the others and +scarcely longer, bluntly pointed; second with a flattened oral surface; +third smaller, similarly flattened, but with a groove on oral surface +forming a notch at its postero-external angle. Fourth premolar short, +with a distinct inner ledge. Molars as in _Macropus_. + +_Dendrolagus._[75]—General proportions of limbs and body normal and +unlike those of other members of the family. Muffle broad and only partly +naked. Fur on nape, and sometimes on back, directed forwards. Fore limbs +nearly as large as the hind; hind feet with the syndactylous second and +third digits relatively large; claws of fourth and fifth hind digits +curved like those of the manus. Tail very long, and thickly furred. Skull +stout, with a short and wide muzzle; the posterior part of the palate +fully ossified, and the auditory bullæ not inflated. A small canine. +Fourth premolar large, but much shorter antero-posteriorly than in the +next genus; molars as in the latter. + +This genus includes four species of Tree-Kangaroos, three of which occur +in New Guinea, while _D. lumholtzi_ is found in North Queensland. They +differ greatly from all the other forms in being chiefly arboreal in +their habits, climbing with facility among the branches of large trees, +and feeding on the bark, leaves, and fruit. They are confined to the +tropical forests of the regions mentioned; and it would appear that we +must regard their resemblance in the proportions of the limbs and habits +to the Phalangers as having been independently acquired. + +_Dorcopsis._[76]—Hind limbs relatively less large than in _Macropus_. +Muffle large, broad, and naked. Ears small. Fur on nape directed wholly +or partially forwards. Hind claws not concealed by hair. Tail with a +nearly naked tip. Skull long and narrow, with the auditory bullæ not +inflated. A well-developed canine. First upper incisor somewhat short; +second and third nearly equal, notched externally. Fourth premolar +greatly elongated antero-posteriorly, its length generally exceeding the +united lengths of the first and second molars; a distinct inner ledge, +and vertical grooves on both sides. Molars low and rounded, with the +median longitudinal bridge between the ridges almost or quite aborted, +and the talon in front of the first transverse ridge very narrow, and not +extending to the inner side. The two series of cheek-teeth parallel, or +nearly so, instead of converging at the extremities. + +Three species of this genus are known, all of which are from New Guinea; +the type being _D. muelleri_. In the characters of the dentition, the +forward inclination of the fur on the nape, and other points, this genus +is allied to _Dendrolagus_; but _Dorcopsis macleayi_ connects the other +species with _Macropus_. + +_Lagorchestes._[77]—Muffle entirely or partially covered with hair. +Fourth hind digit with a long claw, not concealed by hair. Tail rather +short, evenly furred, without a spur. Skull with short muzzle and +diastema, and inflated auditory bulla. Canine present, sometimes very +small. Fourth premolar large, not constricted in the middle, with a +continuous inner ledge. + +This genus includes the Hare-Kangaroos, a group of small hare-like +animals, great leapers and swift runners, which mostly affect the open +grassy ridges, particularly those of a stony character, sleeping in forms +or seats like the common hare. Their limbs are comparatively small, their +claws sharp and slender, and their muffle is clothed with velvet-like +hairs. Three species—_M. leporoides_, _M. hirsutus_, _M. conspicillatus_. + +The range extends over the whole of Australia, but does not embrace +Tasmania. + +_Onychogale._[78]—Muffle hairy. Fourth hind claw long, narrow, +compressed, and sharp. Tail long and tapering, covered with short +hair, and furnished at the tip with a horny spur. Skull nearly as in +_Macropus_, with the auditory bullæ more or less inflated. Canine small +or wanting. Upper incisors small, decreasing in size from first to third. +Fourth premolar small, hour-glass shaped, and without inner ledge. Molars +as in _Macropus_. + +This genus contains three species, having the same distribution as +_Lagorchestes_. Mr. O. Thomas observes: “The spur-tailed Wallabies form +a natural little group, distinguished both by the shape of the incisors +and the peculiar horny excrescence at the tip of the tail. The latter +character is altogether unique among Marsupials, and is only found among +other mammals in the Lion, which occasionally has a somewhat similar +horny spur at the end of its tail. In the case of the Wallabies it is +difficult to conceive what can be the use of this spur; and observations +on the living animal are much needed with regard to this interesting +point.” + +_Petrogale._[79]—Muffle naked. Fur of nape directed backwards. Claw of +fourth hind digit very short. Tail long, cylindrical, thinner than in +_Macropus_, and thickly haired and pencilled at the extremity. Skull +as in the smaller species of _Macropus_, with large posterior palatal +vacuities, and the bullæ sometimes inflated. No canine. Upper incisors +small, the third resembling that of _Macropus_. Fourth premolar large +and stout, as in some of the Wallabies, with a continuous inner ledge, +and two or three indistinct vertical ridges externally. Molars as in the +Wallabies. + +This genus is represented by six species, of which _P. penicillata_ +is a well-known example, ranging over the whole of the mainland of +Australia. The Rock-Wallabies, as its members may be called, are very +closely allied to some of the true Wallabies; and some hesitation may be +expressed as to the advisability of accepting their generic separation +from _Macropus_. They inhabit rocky regions, making their retreats +in caverns and crevices, leaping with surprising agility from one +narrow ledge to another, and browsing upon the scanty herbage that the +neighbourhood of such situations affords. The species are _P. xanthopus_, +_P. penicillata_, _P. lateralis_, _P. concinna_, _P. brachyotis_, _P. +inornata_. + +Remains of _P. penicillata_ are found in a fossil state in the +Pleistocene cave-deposits of New South Wales. + +_Macropus._[80]—Muffle generally completely naked. Ears large. Fur on +nape (with an occasional exception in two species) directed backwards. +Claw of fourth hind digit very long. Tail thick, tapering, and evenly +furred. Four mammæ. Skull (Fig. 55) long, smooth, and rounded; the nasals +expanded behind; generally large palatal vacuities; and the auditory +bullæ not inflated. Canine minute, and shed at an early period. Incisor +series forming an open curve; the first the tallest, and the third nearly +always the longest antero-posteriorly, and generally with an infolding +of enamel near its postero-external angle. Fourth upper premolar with a +secant edge, and an inner basal ledge or tubercle; corresponding lower +tooth secant; both maybe longer or shorter than first molar. Molars +(except very occasionally) with a distinct longitudinal bridge connecting +transverse ridges. Lower incisors long and scalpriform, with inner secant +edges opposable, owing to the loose articulation of the mandibular +symphysis. + +This genus includes the true Kangaroos and Wallabies, the size of the +individual existing species varying from that of a Rabbit to that of a +Man. There are no less than twenty-three existing species, which may be +divided into three groups, as well as many extinct ones. The genus is +found in Australia and New Guinea, as well as in the eastern half of the +Austro-Malayan transitional region. + +The first group, or true Kangaroos, comprises the largest existing forms, +which are generally of a uniform and sombre colour. + +The skull is of a large and massive type, with the palate more or less +well ossified posteriorly, while the molars frequently have a median +longitudinal bridge connecting the first transverse ridge with the +anterior talon, and no antero-external bridge between the same ridge and +talon. The history of the discovery of the typical representative of this +group, as being of considerable interest, may be given at some length. +When Captain Cook, during his first memorable voyage of discovery, was +detained for the purpose of refitting his ship at Endeavour river on +the north-east coast of Australia, a strange-looking animal, entirely +unknown to them, was frequently seen by the ship’s company; and it is +recorded in the annals of the voyage that, on the 14th of July 1770, +“Mr. Gore, who went out this day with his gun, had the good fortune +to kill one of the animals which had been so much the subject of our +speculation, ... and which is called by the natives kanguroo,” a name +which, though it does not appear to be now known to any of the aboriginal +tribes of the country, has been adopted for this animal in all European +languages, with only slight modifications of spelling. With the exception +of a passing glimpse in the beginning of the same century by the Dutch +traveller Bruyn of some living examples of an allied species, this was +the first introduction to the civilised world of any member of a group +of animals now so familiar. The affinities of the species, skins of +which were brought home by Captain Cook and subsequent voyagers, were +recognised by Schreber as nearer to the American opossums (then the +only known Marsupials) than to any other mammals with which zoologists +were acquainted, and consequently it was placed by him, in his great +work on the Mammalia, then in the course of publication, in the genus +_Didelphys_, with _gigantea_ for a specific designation,—the latter +having been bestowed upon it by Zimmermann under the impression that +it was a huge species of jerboa. Soon afterwards (1791) Dr. Shaw very +properly formed a new genus for its reception, which he named _Macropus_, +in allusion to the peculiar length of its hind foot. By the name thus +formed, _Macropus giganteus_, this kind of Kangaroo has ever since been +known in zoological literature. It is the common Gray Kangaroo, called +“boomer,” “forrester,” or “old man” by the colonists, and frequents the +open grassy plains of the greater part of eastern Australia and Tasmania; +a figure being given in the woodcut on p. 160. The muffle is partly +covered with hair, and the fourth premolar very short. Several varieties +are known. + +A sub-group, distinguished from the above by the naked muffle, includes +some very large and handsome species, which principally dwell in rocky +mountain ranges, as _M. rufus_, the great Red Kangaroo, _M. antilopinus_, +and _M. robustus_. The fourth premolar is of large or medium size in +these forms. Remains of _M. giganteus_ occur fossil in the Pleistocene +of Australia, where we also find the allied extinct _M. titan_, which +attains somewhat larger dimensions. _M. robustus_ also dates from the +same geological epoch, where it was accompanied by two allied types known +as _M. altus_ and _M. cooperi_. + +The second group includes the larger Wallabies, which are smaller than +the true Kangaroos, with a brighter and more variegated coloration. The +palate is generally more incomplete than in the typical group; and in the +molars the anterior talon is connected with the first transverse ridge +by an external instead of a median longitudinal bridge. The members of +this group are frequenters of forests and dense impenetrable brushes and +scrubs, and hence are often called Brush Kangaroos, though a native name, +“Wallaby,” is now generally applied to them. There are several species, +of which _M. ruficollis_, _M. ualabatus_, _M. parryi_, and _M. agilis_ +are the best known. + +_M. ualabatus_ and _M. parryi_ are found fossil in the Pleistocene +deposits of Australia. In those beds we also meet with remains of several +very large extinct species, which appear to be allied to those Wallabies +in which the fourth premolar is large and elongated, all of them agreeing +with the Wallabies in the absence of the median bridge between the first +ridge and talon of the molars. These fossil forms comprise _M. brehus_, +in which the skull was probably about one foot in length, and _M. +rœchus_, and _M. anak_, which were of somewhat inferior dimensions. In +the last-named species the length of the fourth upper premolar is equal +to that of the first and half of the second molar.[81] + +The third and last group of the genus includes the small Wallabies, +which are small and lightly-built animals, in some instances not larger +than a Rabbit. Their muffles are always naked, and in the skull the +anterior palatine foramina are small and the posterior vacuities very +large, while the posterior expansion of the nasals is very marked. The +third upper incisor is smaller than in the last group. This group extends +farther into the tropics than either of the others, being found in the +New Britain and Aru islands, as well as in New Guinea. _M. brachyurus_ +is remarkable for its comparatively short and slender tail and small +ears. The earliest known species of Kangaroo, referred to before, _M. +bruni_, belongs to this section. Several examples were seen by Bruyn in +1711 living in captivity in the garden of the Dutch governor of Batavia, +and described and figured in the account of his travels (_Reizen over +Moskovie_, etc.) under the name of “Filander.” It was quite lost sight +of, and its name even transferred by S. Müller to another species +(_Dorcopsis muelleri_), until rediscovered in 1865 by Rosenberg, who +sent a series of specimens to the Leyden Museum from the islands of Aru +and Great Key, thus determining its true habitat. _M. thetidis_ is a +well-known Australian representative of this group. + +_Extinct genera._—In addition to the fossil forms already mentioned which +can be referred to existing genera, there are others from the Australian +Pleistocene indicating extinct generic types of _Macropodidæ_, to which +brief reference may now be made. The first of these is _Sthenurus_,[82] +represented by a single large species (_S. atlas_), and characterised by +the presence of a complete inner lobe to the fourth upper premolar, and +of an outer one in the opposing lower tooth, so that these teeth present +a flat and oval grinding surface when worn. The median longitudinal +bridge connecting the transverse ridges of the molars is very imperfect; +and in the upper molars there is no bridge between the first ridge and +talon. In _Procoptodon_[83] the premolars resemble those of _Sthenurus_, +but the molars are elongated, and usually have their enamel thrown into +numerous vertical foldings. The most distinctive feature is, however, the +complete ankylosis of the mandibular symphysis; the mandibular rami being +deep, and the diastema in the dental series short. The lower incisors are +nearly cylindrical, and the palate has large vacuities. Three species are +known. The largest representation of the whole family is the type of the +genus _Palorchestes_[84] (_P. azael_), in which the length of the skull +is estimated at sixteen inches. It is distinguished from _Procoptodon_ +by the longer mandibular symphysis and diastema, and the spatulate lower +incisors. The true molars have no distinct anterior talon, and are not +grooved, while the palate was fully ossified. + + +EXTINCT FAMILIES. + +Here may be noticed two genera of extinct Marsupials, the remains of +which have been found in the Pleistocene deposits of Australia, which +agree with the _Macropodidæ_ and the _Phalangeridæ_ in having ³⁄₁ +incisors, those of the lower jaw being very large and proclivous. As the +whole of their structure, especially that of the hind feet, is not yet +known, their precise affinities cannot be determined. + +_Diprotodon._[85]—Dentition: _i_ ³⁄₁, _c_ ⁰⁄₀, _p_ ¹⁄₁, _m_ ⁴⁄₄; total +28. The first upper incisor very large and scalpriform (Fig. 56). True +molars with prominent transverse ridges, as in _Macropus_, but wanting +the longitudinal connecting bridge. Anterior and posterior limbs less +disproportionate than in the Kangaroos. Humerus elongated, and differing +from that of nearly all Marsupials in the absence of an entepicondylar +foramen. The palate is fully ossified, and there is no pit or perforation +in the masseteric fossa of the mandible. _D. australis_ is the largest +known Marsupial, being fully equal in bulk to a Rhinoceros. It may be +regarded as the type of a family—_Diprotodontidæ_—having affinity on the +one hand with the Phalangers and on the other with the Kangaroos. + +[Illustration: FIG. 56.—Left lateral aspect of the skull of _Diprotodon +australis_; from the Pleistocene of Australia. ⅒ natural size. _i_, +Incisors; _p_, premolar; _m_, molars. (After Owen.)] + +_Nototherium._[86]—Represented by a species of somewhat smaller size +than the type of _Diprotodon_, with a shorter skull, in which the +zygomatic arches are very wide and the nasals curiously expanded at +their extremities. The mandibular symphysis is ankylosed; and, as in +_Diprotodon_, there appears to have been no tooth-change. The humerus +probably referable to _Nototherium_ is of a short and widely expanded +type, with a large entepicondylar foramen, and coming nearer to that of +the Wombat than to that of any other existing form. The _Nototheriidæ_ +may apparently be regarded as a distinct family connecting the +_Diprotodontidæ_ with the _Phascolomyidæ_ and _Phalangeridæ_. + + _Bibliography of Marsupialia._—G. R. Waterhouse, _Nat. Hist. of + the Mammalia_, vol. i. “Marsupiata,” 1846; J. Gould, _Mammals + of Australia_, 1863; R. Owen, article “Marsupialia,” in + _Cyclop. of Anatomy and Physiology_, and various memoirs “On + Extinct Mammals of Australia” in _Philosophical Transactions_; + W. H. Flower, “On the Development and Succession of the Teeth + in the Marsupialia,” _Phil. Trans._ 1867; O. Thomas, “On the + Homologies and Succession of the Teeth in the Dasyuridæ,” + _Phil. Trans._ 1887; and “Catalogue of Marsupialia and + Monotremata in the British Museum,” 1888. + + + + +CHAPTER VII + +THE SUBCLASS EUTHERIA AND THE ORDER EDENTATA + + +The whole of the remaining groups of mammals are included in a single +subclass, known by the names Eutheria, Monodelphia, or Placentalia.[87] +The one distinctive feature they have in common (from which the +last-mentioned name is derived) is the presence of an allantoic placenta +by means of which the fœtus is nourished within the uterus of the mother. +Throughout the entire subclass, as a general rule, the urino-genital +organs open quite independently of the rectum; the corpus callosum of the +brain is well developed; the mandible does not show a marked inflection +of its angle; and distinct epipubic bones are not attached to the +anterior margin of the pubic symphysis. In those cases where there is a +heterodont and diphyodont dentition the dental formula can be reduced to +some modification of the one given on p. 25, there being only one known +genus where four true molars occur, and even that not invariably. As +in the Metatheria, the coracoid is reduced to a mere appendage of the +scapula, and the acetabular cavity of the pelvis is imperforate. While +the survivors of the other subclasses have probably been for a long time +in a stationary condition, these have, as there is already good evidence +to show throughout all the Tertiary geological age, and by inference +for some time before, been multiplying in numbers and variations of +form, and attaining higher stages of development and specialisation in +various directions. They consequently exhibit far greater diversity of +external or adaptive modification than is met with in either of the other +subclasses,—some being fitted to live as exclusively in the water as +fishes, and others to emulate the aerial flight of birds. + +To facilitate the study of the different component members of this large +group, it is usual to separate them into certain divisions which are +called “orders.” In the main zoologists are now of accord as to the +general number and limits of these divisions among the existing forms, +but the affinities and relationships of the orders to one another are +far from being understood, and there are very many extinct forms already +discovered which do not fit at all satisfactorily into any of the orders +as commonly defined. + +Commencing with the most easily distinguished, we may first separate +a group called Edentata, composed of several very distinct forms, the +Sloths, Anteaters, and Armadillos, which under great modifications of +characters of limbs and digestive organs, as well as habits of life, +have just enough in common to make it probable that they are the very +specialised survivors of an ancient group, most of the members of +which are extinct, although the researches of palæontology have not +yet revealed them to us. The characters of their cerebral, dental, and +in many cases of their reproductive organs show an inferior grade of +organisation to that of the generality of the subclass. The next order, +about the limits of which there is no difficulty, is the Sirenia,—aquatic +vegetable-eating animals, with complete absence of hind limbs, and low +cerebral organisation,—represented in our present state of knowledge by +but two existing genera, the Dugongs and Manatees, and by a few extinct +forms, which, though approaching a more generalised mammalian type, show +no special characters allying them to any of the other orders. Another +equally well-marked and equally isolated, though far more numerously +represented and diversified order, is that of the Cetacea, composed of +the various forms of Whales, Dolphins, and Porpoises. In aquatic habits, +external fish-like form, and absence of hind limbs, they resemble the +last, though in all other characters they are as widely removed as are +any two orders among the Eutheria. + +All the remaining orders are more nearly allied together, the steps by +which they have become modified from one general type being in most cases +not difficult to realise. Their dentition especially, however diversified +in detail, always responds to the formula already alluded to, and, +although the existing forms are broken up into groups in most cases easy +of definition, the discoveries already made in palæontology have in great +measure filled up the gaps between them. + +Very isolated among existing Eutheria are the two species of Elephant +constituting the group called Proboscidea. These, however, are now known +to be the survivors of a large series of similar animals, Mammoths, +Mastodons, and Dinotheres, which as we pass backwards in time gradually +assume a more ordinary or generalised type; and the interval which was +lately supposed to exist between even these and the rest of the class +is partially bridged over by the discovery in American Eocene and early +Miocene formations of the gigantic Dinocerata, evidently offshoots of +the great group of hoofed animals, or Ungulata, represented in the +actual fauna by the Horses, Rhinoceroses, Tapirs, Swine, and Ruminants. +Almost as isolated as the Proboscidea among existing mammals are the +few small species constituting the family _Hyracidæ_, and in their case +palæontology affords no help at present, and therefore, pending further +discoveries, it has been thought advisable in most recent systems to +give them the honour of an order to themselves, under the name of +Hyracoidea. But the number of extinct forms already known allied to +the Ungulata, though not coming under the definition of either of the +two groups (Artiodactyla and Perissodactyla) under which all existing +species range themselves, is so great that either many new orders must +be made for their reception or the definition of the old order Ungulata +so far extended as to receive them all, in which case both Proboscidea +and Hyracoidea may be included within it. Again, the Rodentia or gnawing +animals—Rabbits, Rats, Squirrels, Porcupines, Beavers, etc.—are, if +we look only at the present state of the class, most isolated. No one +can doubt what is meant by a Rodent animal, or have any difficulty +about defining it clearly, at least by its dental characters; yet our +definitions break down before the extinct South American _Typotherium_, +half Rodent and half Ungulate, which leads by an easy transition to +the still more truly Ungulate _Toxodon_, for the reception of which a +distinct order (Toxodontia) has been proposed. It has also been suggested +that the Rodents are connected by some of the extinct Tillodontia (or +Tæniodontia) with the Edentates. The Insectivora and the Carnivora +again are at present quite distinct orders, but they merge into one +another through fossil forms, and are especially connected by the large +group of primitive Carnivora, so abundantly represented in the Eocene +deposits both of America and Europe, to which Cope has given the name +of Creodonta. The Carnivora also appear to have been closely connected +with the primitive Ungulates as represented by the extinct group called +Condylarthra. In another direction the step from the Insectivores to +the Lemurs is not great, and in past times the transition was probably +complete. The Bats or Chiroptera are allied to the Insectivora in all +characters except the extraordinary modification of their anterior +extremities into wings; but this, like the want of the hind limbs in the +Cetacea and Sirenia, makes such a clear distinction between them and all +other mammals that, in the absence of any knowledge of any completely +intermediate or transitional forms, they can be perfectly separated, +and constitute as well-defined an order as any in the class. We have, +however, an inkling of the mode in which the Insectivora were modified +into Chiroptera shown us by the so-called Flying Lemur (_Galeopithecus_). +Finally, we have the important and well-characterised group called +Primates, including all the Monkeys and Man; and the question is not yet +solved as to how and through what forms this is linked on to the other +groups. It is commonly assumed that the Lemurs are nothing more than +inferior Primates, but the interval between them in the actual fauna of +the world is very great, and our knowledge of numerous extinct types +recently discovered in America, said to be intermediate in characters, +is not yet sufficient to enable us to form a definite opinion upon the +subject. + +The Edentata may be taken first as standing in some respects apart from +all the others; and the Primates must be placed at the head of the +series. The position of the others is quite arbitrary, as none of the +hitherto proposed associations of the orders into larger groups stand +the test of critical investigation, and palæontological researches have +already gone far to show that they are all modifications of a common +heterodont, diphyodont, pentadactylate form. + + +_Order_ EDENTATA. + +The name assigned to this group (which some zoologists think ought +rather to be ranked as a subclass[88] than an order) by Cuvier is often +objected to as inappropriate—for although some of the members are +edentulous, others have very numerous teeth—and the Linnæan name Bruta +is occasionally substituted. But that term is quite as objectionable, +especially since the group to which Linnæus applied it is by no +means equivalent to the order as now understood, as the names of the +genera contained in it, viz. _Elephas_, _Trichechus_, _Bradypus_, +_Myrmecophaga_, _Manis_ and _Dasypus_, indicate. It contained, in fact, +all the animals then known which are comprised in the modern groups +of Proboscidea, Sirenia and Edentata together with the Walrus, one +of the Carnivora. If retained at all, it should rather belong to the +Proboscidea, as _Elephas_ stands first in the list of genera in the +_Systema Naturæ_. Cuvier’s order included the _Ornithorhynchus_ and +_Echidna_, the structure of which was then imperfectly known, and which +are now by common consent removed to an altogether different section +of the class; but otherwise its limits are those now adopted. The name +Edentata is so generally used, and its meaning so well understood, that +it would be undesirable to change it now; in fact similar reasons might +be assigned for ceasing to use nearly all the other current ordinal +designations, for it might be equally well objected that all Carnivora +are not flesheaters, many of the Marsupialia have not pouches, and so +forth. + +If the teeth are not always absent, they invariably exhibit certain +imperfections, which are indeed almost the only common characters +binding together the various extinct and existing members of the order. +These are—that they are homodont and, with the remarkable exceptions +of _Tatusia_ and _Orycteropus_, monophyodont; they are never rooted, +but have persistent pulps; except in some fossil forms, they are always +deficient in one of the constituents which enter into the formation of +the complete mammalian tooth, the enamel; and, at least among living +forms, are never present either in the upper or lower jaw in the fore +part of the mouth, the situation occupied by the incisors of other +mammals.[89] + +The peculiar nature of the dentition in the aberrant _Orycteropus_ will +be noticed under the heading of that genus. As a rule, the coracoid +process of the scapula of the Edentates is more developed than in other +Eutheria. + +The degree of development of the brain varies considerably in the +different families, the hemispheres being in some cases almost or quite +smooth (Fig. 57), with a small corpus callosum, and large anterior +commissure; while in other instances the hemispheres are convoluted, and +the corpus callosum is larger. + +[Illustration: FIG. 57.—Upper surface of the brain of the Broad-banded +Armadillo (_Xenurus unicinctus_). The large olfactory lobes are seen at +the anterior extremity (left of figure); the hemispheres have only three +sulci. (From Garrod, _Proc. Zool. Soc._ 1878, p. 230).] + +There is so great a difference in structure and habits between some of +the existing animals assigned to this order that, beyond the negative +characters just mentioned, there seems little to connect them. The Sloths +and Anteaters, for instance, in mode of life, general conformation of +limbs, structure of digestive organs, etc., appear at first sight almost +as widely separated as any mammals. Palæontology has, however, thrown +great light upon their relations, and proved their real affinities. +Perfectly intermediate forms have been discovered in the great Ground +Sloths of America, which have the dentition and general form of the +head of the Sloths, combined with the limbs and trunk of the Anteaters. +It is, indeed, highly probable that the existing members of this order +are very much differentiated representatives of a large group, the +greater number of which are now extinct, and have become so without ever +attaining a high grade of organisation. The great diversity of structure +in the existing families, the high degree of specialisation to which many +have attained, the paucity of species and even of individuals, their +limited area of distribution, and their small size compared with known +ancestral forms, all show that this is an ancient and a waning group, the +members of which seem still to hold their own either by the remoteness +and seclusion of their dwelling-places, by their remarkable adaptation +of structure to special conditions of life, or by aid of the peculiar +defensive armature with which they are invested. Their former history +can, however, only be thus surmised, rather than read, at present; for, +though we have ample evidence of the abundance and superior magnitude of +certain forms in the most recent or Pleistocene geological age, yet we +have at present no definite evidence as to their origin, or relationship +to other orders of mammals. + +The existing members of the order readily group themselves into five +distinct families, the limits of which are perfectly clear. These are +(1) _Bradypodidæ_, or Sloths; (2) _Myrmecophagidæ_, or Anteaters; +(3) _Dasypodidæ_, or Armadillos; (4) _Manidæ_, Pangolins or Scaly +Anteaters; and (5) _Orycteropodidæ_, Aard-varks or African Anteaters. +The geographical distribution of these families coincides with their +structural distinction, the first three being inhabitants of the New +and the last two of the Old World. It has been usual to arrange these +families into two large groups or suborders: (1) the Phyllophaga, +leaf-eaters, also called Tardigrada, containing the _Bradypodidæ_ alone; +and (2) the Entomophaga, insect-eaters, or Vermilingua, containing +all the other families, from which sometimes the _Orycteropodidæ_ +are separated as a third suborder under the name of Effodientia, or +Tubulidentata. Such an arrangement is, however, an artificial one, +founded on superficial resemblance. The bonds which unite the _Manidæ_ +to the _Myrmecophagidæ_ are mainly to be found in the structure of the +mouth, especially the extensile character of the tongue, the great +development of the submaxillary glands, and the absence of teeth. +These characters are exactly analogous to those found in the Echidna +among Monotremes, the Woodpeckers among Birds, and the Chameleon among +Reptiles,—the fact probably being that in countries where Termites and +similar insects flourish various distinct forms of vertebrates have +become modified in special relation to this abundance of nutritious +food, which could only be made available by a peculiar structure of the +alimentary organs. A close study of the more essential portions of the +anatomy of these animals[90] leads to the belief that all the American +Edentates at present known, however diversified in form and habits, +belong to a common stock. Thus the _Bradypodidæ_, _Megatheriidæ_, and +_Myrmecophagidæ_ are certainly allied, the modifications seen in the +existing families relating only to food and manner of life. The ancestral +forms may have been omnivorous, and gradually separated into the purely +vegetable and purely animal feeders; from the former are developed +the modern Sloths, from the latter the Anteaters. The Armadillos +(_Dasypodidæ_) are another modification of the same type, retaining some +generalised characters, as those of the alimentary organs, but in other +respects, as in their defensive armature, remarkably specialised. The +two Old World families _Manidæ_ and _Orycteropodidæ_ are so essentially +distinct, both from the American families and from each other, that it +may even be considered doubtful whether they are derived from the same +primary branch of mammals, or whether they may not be offsets of some +other branch, the remaining members of which have been lost to knowledge. +Further remarks on this point are recorded under the description of the +_Orycteropodidæ_.[91] + + +_Family_ BRADYPODIDÆ. + +Externally clothed with long, coarse, crisp hair. Head short and rounded. +External ears inconspicuous. Teeth ⁵⁄₄ in each jaw, subcylindrical, of +persistent growth, consisting of a central axis of vaso-dentine, with a +thin investment of hard dentine, and a thick outer coating of cement; +without (so far as is yet known) any succession. Clavicles present. Fore +limbs greatly longer than the hind limbs. All the extremities terminating +in narrow, curved feet; the digits never exceeding three in number, +encased for nearly their whole length in a common integument, and armed +with long strong claws. Tail rudimentary. Stomach complex. No cæcum. +Uterus simple and globular. Placenta deciduate, dome-like, composed of an +aggregation of numerous discoidal lobes. Strictly arboreal in habits, +vegetable feeders, and limited geographically to the forest regions of +South and Central America. + +[Illustration: FIG. 58.—Two-toed Sloth (_Cholœpus hoffmanni_).] + +The Sloths, as the animals of this family are called on account of the +habitual sluggishness of their movements, are the most strictly arboreal +of all mammals, living entirely among the branches of trees, usually +hanging under them, with their backs downwards (Fig. 58), and clinging +to them with the simple hook-like organs to which the terminations of +all their limbs are reduced. When they are obliged from any cause to +descend to the ground, which they rarely, if ever, do voluntarily, their +limbs, owing to their unequal length and the peculiar conformation of the +feet—which allows the animals to rest only on the outer edge—are most +inefficient for terrestrial progression, and they crawl along a level +surface with considerable difficulty. Though generally slow and inactive, +even when in their natural haunts, Sloths can on occasions travel with +considerable rapidity along the branches; and, as they do not leap, like +most other arboreal creatures, they avail themselves of the swaying of +the boughs by the wind to pass from tree to tree. They feed entirely on +leaves and young shoots and fruits, which they gather in their mouth, the +fore limbs aiding in dragging boughs within reach, but not being used +like hands, as they are by monkeys, squirrels, etc. When sleeping they +roll themselves up in a ball, and, owing to the dry shaggy character of +their hair, are very inconspicuous among the mosses and lichens with +which the trees of their native forests abound; the concealment thus +afforded being heightened in some species by the peculiar greenish tint +of the outer covering—very uncommon in mammals. This is not due to the +colour of the hair itself, but to the presence upon its surface of an +alga, the lodgment of which is facilitated by the fluted or rough surface +of the exterior of the hair, and the growth of which is promoted by the +dampness of the atmosphere in the gloomy tropical forests, as it soon +disappears from the hair of animals kept in captivity in England. Sloths +are nocturnal, silent, inoffensive, and solitary animals, and usually +produce but one young at birth. They appear to show an almost reptilian +tenacity of life, surviving the most severe injuries and large doses of +poisons, and exhibiting longer persistence of irritability of muscular +tissue after death than other mammals. + +In the _Bradypodidæ_, as well as in the _Myrmecophagidæ_, the testes +are placed close to each other, lying on the rectum between it and the +bladder; the penis is quite rudimentary, consisting of a pair of small +corpora cavernosa, not directly attached by their crura to the rami +of the ischia, and having a glans scarcely larger than that of the +clitoris of most mammals, and, as in birds and reptiles, without any +true corpus spongiosum. In the females of both families the uterus is +simple and globular; and the vagina, at least in the virgin state, is +divided into two channels by a strong median partition. The deciduate +placenta of _Cholœpus_ is composed of a number of lobes aggregated into a +dome-like mass; and it does not appear that the placenta of the Anteaters +departs in any important characters from this type. According to the +late Professor W. K. Parker, the embryos of the Sloths, Anteaters, and +Pangolins have the stapes of the middle ear in the form of a rod, thus +showing affinities with a very primitive type of mammalian organisation. + +The Sloths were all included in the Linnæan genus _Bradypus_, but Illiger +very properly separated the species with but two claws on the fore feet, +under the name of _Cholœpus_, leaving _Bradypus_ for those with three. + +_Bradypus._[92]—Three-toed Sloths. Teeth usually ⁵⁄₄ on each side; no +tooth projecting greatly beyond the others; the first in the upper jaw +much smaller than any of the rest; the first in the lower jaw broad and +compressed; the grinding surfaces of all much cupped. Vertebræ: C 9, D +and L 20 (of which 15 to 17 bear ribs), S 6, C 11. All the known species +present the remarkable peculiarity of possessing nine cervical vertebræ, +_i.e._ nine vertebræ in front of the one which bears the first thoracic +rib (or first rib connected with the sternum, and corresponding in its +general relations with the first rib of other mammals); but the ninth, +and sometimes the eighth, bears a pair of short movable ribs. The arms +or fore limbs are considerably longer than the hind legs. The bones of +the fore arm are complete, free, and capable of pronation and supination. +The hand is long, very narrow, habitually curved, and terminates in three +pointed curved claws, in close apposition with each other. The claws are, +in fact, incapable of being divaricated, so that the hand is reduced to +the condition of a triple hook, fit only for the function of suspension +from the boughs of trees. The foot closely resembles the hand in its +general structure and mode of use; the sole being habitually turned +inwards, so that it cannot be applied to the ground in walking. The +tongue is short and soft, and the stomach large and complex, bearing some +resemblance to that of the ruminating Ungulates. The windpipe or trachea +has the remarkable peculiarity among mammals—not unfrequent among birds +and reptiles—of being folded on itself before it reaches the lungs. The +mammæ are two, and pectoral in position. + +“Ai” is the common name given in books to the Three-toed Sloths. They +were all comprised by Linnæus under the species _Bradypus tridactylus_. +More recently Dr. Gray described as many as eleven species, ranged in two +genera, _Bradypus_ and _Arctopithecus_; but the distinctions which he +assigned both to species and genera do not bear close examination. Some +are covered uniformly with a gray or grayish-brown coat; others have a +dark collar of elongated hairs around the shoulders (_B. torquatus_); +some have the hair of the face very much shorter than that of the rest +of the head and neck; and others have a remarkable-looking patch of soft +short hair on the back between the shoulders, consisting, when best +marked, of a median stripe of glossy black, bordered on each side by +bright orange, yellow, or white. There are also structural differences in +the skulls, as in the amount of inflation of the pterygoid bones, which +indicate real differences of species; but the materials in our museums +are not yet sufficient to correlate these with external characters and +geographical distribution. The habits of all are apparently alike. They +are natives of Guiana, Brazil, and Peru, and one if not two species (_B. +infuscatus_ and _B. castaneiceps_) extend north of the Isthmus of Panama +as far as Nicaragua. Of the former of these Dr. Seeman says that, though +generally silent, a specimen in captivity uttered a shrill sound like a +monkey when forcibly pulled away from the tree to which it was holding. + +_Cholœpus._[93]—Teeth ⁵⁄₄; the most anterior in both jaws separated by +an interval from the others, very large, caniniform, wearing to a sharp, +bevelled edge against the opposing tooth, the upper shutting in front of +the lower when the mouth is closed (Fig. 59), unlike the true canines +of heterodont mammals. Vertebræ: C 6 or 7, D 23-24, L 3, S 7-8, C 4-6. +One species (_C. didactylus_) has the ordinary number of vertebræ in +the neck; but an otherwise closely allied form (_C. hoffmanni_) has but +six. The tail is very rudimentary. The hand generally resembles that of +_Bradypus_; but there are only two functional digits with claws—those +answering to the second and third of the typical pentadactylate manus. +The structure of the hind limb generally resembles that of _Bradypus_, +the appellation “two-toed” referring only to the anterior limb, for +in the foot the three middle toes are functionally developed and of +nearly equal size. _C. didactylus_, which has been longest known, is +commonly called by the native name of _Unau_. It inhabits the forests +of Brazil. _C. hoffmanni_ (Fig. 58) has a more northern geographical +range, extending from Ecuador through Panama to Costa Rica. Its voice, +which is seldom heard, is like the bleat of a sheep, and if the animal is +seized it snorts violently. Both species are very variable in external +coloration. + +[Illustration: FIG. 59.—Skull of Two-toed Sloth (_Cholœpus didactylus_). +From _Proc. Zool. Soc._ 1871, p. 432.] + +_Nothropus._[94]—The only fossil form which has been referred to this +family is indicated by a lower jaw, described by Dr. Burmeister, from the +Pleistocene of Argentina, which appears to have belonged to an animal +of about double the dimensions of _Cholœpus didactylus_. Professor Cope +states, however, that this jaw really belongs to a Glyptodont; while it +is referred by Dr. Ameghino to the next family. + + +_Family_ MEGATHERIIDÆ. + +[Illustration: FIG. 60.—Section of upper molar teeth of _Megatherium +americanum_. × ⅓. _p_, pulp-cavity; the other letters explained in the +text. (After Owen.)] + +The members of this family are all extinct. Their characters, so far as +is known from the well-preserved remains of many species found abundantly +in deposits of Pleistocene age in both North and South America, were +intermediate between those of the existing _Bradypodidæ_ and the +_Myrmecophagidæ_, combining the head and dentition of the former with +the structure of the vertebral column, limbs, and tail of the latter. +Almost all the known species are of comparatively gigantic size, the +smallest, _Nothrotherium escrivanense_, exceeding the largest existing +Anteater, and the Megatherium being larger than a Rhinoceros. The femur +has no third trochanter, and the odontoid process of the axis vertebra +has a peculiar facet on the ventral surface. The dentition is usually +⁵⁄₄ on each side, as in the Sloths, but ⁴⁄₃ in _Nothrotherium_.[95] +This genus, and in a still more marked degree _Megatherium_, differ +from all the others in the details of the structure of the teeth. They +are very deeply implanted, of prismatic form (quadrate in transverse +section), and the component tissues—hard dentine (Fig. 60, _d_), softer +vaso-dentine (_v_), and cement (_c_)—are so arranged that, as the tooth +wears, the surface always presents a pair of transverse ridges, thus +producing a triturating apparatus comparable to the “bilophodont” molar +of _Dinotherium_, _Tapirus_, _Manatus_, _Macropus_, and others, though +produced in a different manner. In all the other genera the teeth are +more or less cylindrical, though sometimes laterally compressed or even +longitudinally grooved on the sides, and on the grinding surface the +prominent ridge of hard dentine follows the external contour, and is +surrounded only by a thin layer of cement, as in the existing Sloths. +The Ground Sloths, as the members of this family may be conveniently +designated, agree with the Sloths and Anteaters, and thereby differ from +all other mammals, in that the coracoid process of the scapula and the +coracoidal border of the same unite over the coraco-scapular notch, which +is thus converted into a foramen. Large clavicles are present. + +_Megatherium._[96]—The typical genus _Megatherium_, as being the longest +known representative of the family, may be noticed in some detail. A +nearly complete skeleton, found on the banks of the River Luxan, near +Buenos Ayres, and sent in 1789 to the Royal Museum at Madrid, long +remained the principal if not the only source of information with regard +to the species to which it belonged, and furnished the materials for +many descriptions, notably that of Cuvier, who determined its affinities +with the Sloths.[97] In 1832 an important collection of bones of the +Megatherium was discovered near the Rio Salado, and secured for the +Museum of the College of Surgeons of England; and these, with another +collection found at Luxan in 1837, and now in the British Museum, +supplied the materials for the complete description of the skeleton +published by Sir R. Owen in 1861. Other skeletons have subsequently been +received by several of the Continental museums, as Milan and Paris, and +also by those in South America; and consequently our knowledge of the +organisation of the Megatherium, so far as it can be deduced from the +bones and teeth, is as complete as that of any other animal, recent or +extinct. + +[Illustration: FIG. 61.—Oral surface of mandible of _Megatherium +americanum_. _a_, Condyle; _b_, masseteric process; _c_, angle; _d_, +symphysis. (After Owen.)] + +The remains hitherto spoken of are all referred to one species, +_Megatherium americanum_ of Blumenbach (_M. cuvieri_ of Desmarest), and +are all from the newest or Pleistocene geological formations of the +Argentine Republic and Paraguay, or the lands forming the basin of the +Rio de la Plata. Dr. Leidy has described, from similar formations in +Georgia and South Carolina, bones of a closely allied species, about +one-fourth smaller, which he has named _M. mirabile_. Three other South +American species have been described; but _M. laurillardi_, of Lund, +founded upon remains found in Brazil, has been made the type of the genus +_Ocnopus_. + +[Illustration: FIG. 62.—Skeleton of _Megatherium_, from the specimen in +the Museum of the Royal College of Surgeons. × ¹⁄₂₅.] + +The following description will apply especially to the best-known +South American form, _Megatherium americanum_. In size it exceeded any +existing land animal except the elephant, to which it was inferior only +in consequence of the comparative shortness of its limbs; for in length +and bulk of body it was its equal, if not superior. The full length of +a mounted skeleton (Fig. 62), from the fore part of the head to the end +of the tail, is 18 feet, of which the tail occupies 5 feet. The head, +which is small for the size of the animal, presents a general resemblance +to that of the Sloth; the anterior part of the mouth is, however, more +elongated, and the jugal bone, though branched posteriorly in the same +way as that of the Sloth, meets the zygomatic process of the squamosal, +thus completing the arch. The lower jaw has the middle part of its +horizontal ramus curiously deepened, so as to admit of implantation of +the very long-rooted teeth, the peculiar structure of which has been +already described. A skull recently discovered shows that, instead of the +wide gap between the extremity of the nasals and the premaxillæ exhibited +in Fig. 62, there was a prenasal bone, towards which a process extended +upwards and backwards from the extremity of the upper surface of the +premaxillæ. + +The vertebral column consists of seven cervical, sixteen dorsal, three +lumbar, five sacral, and eighteen caudal vertebræ. The spinous processes +are much better developed than in the Sloths, and are all directed +backwards, there being no reversing of the inclination near the posterior +end of the dorsal series, as in most active-bodied mammals. In the lumbar +region, the accessory zygapophyses, rudimentary in Sloths, are fully +developed, as in the Anteaters. + +The tail is large, and its basal vertebræ have strong lateral and spinous +processes and chevron bones, indicating great muscular development. +The scapula resembles that of the Sloths in the union of the acromion +with the coracoid, and in the bridging over of the suprascapular notch. +The clavicle is complete and very large, much resembling that of man +on a large scale. The fore limbs are longer than the hind limbs. The +humerus has no entepicondylar foramen. The radius and ulna are both +well developed, and have a considerable amount of freedom of movement. +The hand is singularly modified. The pollex is represented only by +a rudimentary metacarpal, but the next three digits are large, and +terminate in phalanges adapted for the support of immense claws, the +middle one being especially large. The outer or fifth digit has no claw, +and it may be considered as certain that the weight of the foot was, in +standing and walking, chiefly thrown upon this one, which was protected +by a callous pad below, as in the existing great Anteater, while the +other toes were curved inwards towards the palm, and only came in contact +with the ground by their outer surfaces. The mechanical arrangements by +which the weight of the body was thrown entirely upon the outer side of +the foot are very curious, and are fully described in Owen’s memoir. The +pelvis is remarkably wide, even more so than that of the Elephant, but it +is formed on the same principle as in the Sloths. The femur is extremely +broad and flattened; the tibia and fibula are short and strong, and +united together at each end. The hind foot, contrary to the usual rule +in the Edentata, is even more singularly modified than the hand. Thus +the ankle-joint is formed upon a peculiar plan, quite unlike that of the +Sloths, or of any other mammal, except the Megatherium’s nearest allies; +and the calcaneum projects nearly as far backwards as the fore part of +the foot does forwards. There is no trace of great toe or hallux, or of +its corresponding cuneiform bone; the second toe is rudimentary; while +the third has an enormous ungual phalanx, which, as in those of the hand, +is remarkable for the immense development of the bony sheath reflected +from its proximal end around the base of the claw. The two outer toes +have large and very peculiarly-shaped metatarsals, but only small +phalanges, and no claws. The creature probably walked upon the outer edge +of the sole, so that the great falcate claw of the third toe did not come +into contact with the ground, and so was kept in a state of sharpness +ready for use. The foot was therefore formed upon quite a different +principle from that of the Anteaters or Sloths, though somewhat like the +latter in having two of the toes aborted. + +Taking all the various points of its structure together, they clearly +indicate affinities both with the existing Sloths and with the +Anteaters, the skull and teeth more resembling those of the former, and +the vertebral column and limbs the latter. It is also not difficult +to infer the food and habits of this enormous creature. That it was a +leaf-eater there can be little doubt; but the greater size and more +complex structure of its teeth might have enabled it to crush the smaller +branches as well as the leaves and succulent shoots which form the food +of the existing Sloths. It is, however, very improbable that it climbed +into the branches of the trees like its diminutive congeners, and it is +far more likely that it obtained its subsistence by tearing them down +with the great hook-like claws of its powerful prehensile fore limbs, +being easily enabled to reach them by raising itself up upon the massive +tripod formed by the two hind feet, firmly fixed to the ground by the one +huge falcate claw, and the stout, muscular tail. The whole conformation +of the hinder part of the animal is strongly suggestive of such an +action. There can also be little doubt but that all its movements were as +slow and deliberate as those of its modern representatives. + +An idea at one time prevailed that the Megatherium was covered externally +with a coat of bony armour like that of the Armadillos; but this +originated in dermal plates belonging to the Glyptodon having been +accidentally associated with bones of the Megatherium. Similar plates, +on a smaller scale, have indeed been found in connection with the +skeleton of the Mylodon, but never yet with the Megatherium, which we may +therefore imagine with a covering of coarse hair like that of its nearest +living allies, the Sloths and Anteaters. + +_Scelidotherium_, _Mylodon_, etc.—Of the more important remaining +genera of this family a briefer notice will suffice. _Scelidotherium_ +(in which _Platyonyx_ may be included) comprises several species of +considerably smaller dimensions than the Megatherium, and is in some +respects intermediate between that genus and _Mylodon_. The teeth have +an oval cross-section, like those of the Sloths, while the skull, in +which the length of the nasals is subject to great variation in the +different species, approximates more or less closely to that of the +_Myrmecophagidæ_. The humerus generally has an entepicondylar foramen; +and the form and relations of the bones of the feet differ considerably +from those obtaining in the type genus. _S. leptocephalum_, the type of +the genus, occurs in Patagonia and Argentina but other species are found +in Brazil and Chili. The genus _Mylodon_, in its widest sense, may be +taken to include a number of comparatively large Edentates, some of which +have been described under the names of _Grypotherium_, _Lestodon_, and +_Pseudolestodon_. The teeth of the upper jaw are generally of an oval or +subtriangular section; and in the more typical forms the first and second +teeth are separated by a short interval, the former being horizontally +worn. In other species, however, like _M. (Lestodon) armatus_, there is +a considerable space between the first and second teeth, and the first +is worn obliquely. The skull is exceedingly like that of the Sloths in +general contour; and there is not the descending process at the angle of +the mandible found in _Megatherium_. The humerus has no entepicondylar +foramen. The species represented in Fig. 63 is from the Pleistocene of +South America; but the type of the genus is _M. harlani_, from beds +of corresponding age in Kentucky. The Patagonian _M. (Grypotherium) +darwini_ is a remarkable form, characterised by the presence of a +bony arch connecting the premaxillæ with the nasals, of which, as +already mentioned, there is an incomplete development in _Megatherium_. +_Megalonyx_, from the Pleistocene of Kentucky, differs from _Mylodon_ by +the long interval between the first and second teeth, and also by the +presence of an entepicondylar foramen in the humerus. _Nothrotherium_ +is a smaller form, occurring in the deposits of the Brazilian caves, of +which the dental features have been already mentioned. The osteological +characters of these and other allied genera have been fully described +in the works of Cuvier, Owen, Burmeister, Leidy, Ameghino, Gervais, +Reinhardt, and others. + +[Illustration: FIG. 63.—Skeleton of _Mylodon robustus_ (Pleistocene, +South America). From Owen.] + +_Promegatherium._—Two genera from the infra-Pampean beds of Argentina, +described as _Promegatherium_ and _Promylodon_, are respectively +distinguished from _Megatherium_ and _Mylodon_ by the presence of bands +of enamel on the teeth, which points to the descent of the Edentates from +mammals with enamelled teeth. + +The Tertiary North American forms described as _Moropus_ and +_Morotherium_,[98] and originally regarded as Edentates, would appear to +be aberrant Ungulates. + + +_Family_ MYRMECOPHAGIDÆ. + +Externally clothed with hair. No teeth. Head elongated. Mouth tubular, +with a small terminal aperture, through which the long, vermiform tongue, +covered with the viscid secretion of the enormous submaxillary glands, +is rapidly protruded in feeding, and withdrawn again with the adhering +particles of aliment, which are then sucked into the pharynx. Clavicles +rudimentary. In the manus, the third toe is greatly developed, and has +a long falcate claw, the others are reduced or suppressed. The pes has +four or five subequal digits with claws. Posterior dorsal and lumbar +vertebræ, with additional interlocking zygapophyses. Tail long, sometimes +prehensile. Uterus simple. Placenta dome-like or discoidal. Brain fairly +convoluted, and with a large corpus callosum and anterior commissure. +The animals of this family are the “Anteaters” _par excellence_. They +feed exclusively on animal substances, mostly insects. One species is +terrestrial, the others arboreal; none burrow in the ground. They are all +inhabitants of the Neotropical region. + +The reproductive organs, as noticed on p. 181, are of the same general +type as in the _Bradypodidæ_. + +_Myrmecophaga._[99]—Skull greatly elongated and narrow, its upper +surface smooth and cylindriform. Anteriorly the face is produced into a +long, tubular rostrum, rounded above and flattened below, with terminal +nares, and composed of the mesethmoid ossified for more than half its +length, the vomer, the maxillæ, and the long and narrow nasal bones, +the premaxillæ being extremely short and confined to the margin of the +anterior nares. The zygomatic arch is incomplete, the styliform jugal +only articulating with the maxilla in front, and not reaching to the +very short zygomatic process of the squamosal. The lachrymal foramen is +in front of the margin of the orbit. There are no postorbital processes +to the frontals, or any other demarcation between the orbits and the +temporal fossæ. Palate extremely elongated, and produced backwards as +far as the level of the external auditory meatus by the meeting in +the middle line of the largely developed pterygoids. The glenoid fossa +a shallow oval facet, with its long diameter from before backwards. +Mandible very long and slender with an exceedingly short symphysis, no +distinct coronoid process, and a slightly elevated, elongated, flattened, +condylar articular surface. Vertebræ: C 7, D 15-16, L 3-2, S 6, C 31. +Clavicles rudimentary. In the manus the first digit is very slender, the +second also slender, with compressed phalanges of nearly equal length. +The third digit is immensely developed; though its proximal phalanx is +extremely short, its ungual phalanx is so long that the entire length of +the digit exceeds that of the second. The fourth has a long and rather +slender metacarpal, and three phalanges diminishing in size, the ungual +phalanx being very small. The fifth has the metacarpal nearly as long, +but not so stout, as the fourth, and followed by two small phalanges, the +last rudimentary and conical. Claws are developed upon all but the fifth. +In walking the toes are kept strongly flexed, and have their points +turned upwards and inwards, the weight being supported upon a callous pad +over the end of the fifth digit, and by the dorsal surfaces of the third +and fourth digits. The hind feet are short and rather broad, with five +subequal claws, the fourth the longest, the first shortest; the whole +sole is placed on the ground in walking. Body rather compressed, clothed +with long, coarse hair. Tail about as long as the body, and covered with +very long hair; not prehensile. Ears small, oval, erect. Eyes very small. +Stomach consisting of a subglobular, thin-walled, cardiac portion, and +a muscular pyloric gizzard with dense epithelial lining. No ileo-colic +valve, and a short wide ill-defined cæcum. Mammæ two, pectoral. + +There is one species,[100] _M. jubata_, the Great Anteater, or Ant Bear +(Fig. 64), measuring 4 feet in length without the tail, and upwards of +2 feet in height at the shoulder. Its prevailing colour is gray, with +a broad black band, bordered with white, commencing on the chest, and +passing obliquely over the shoulder, diminishing gradually in breadth +as it approaches the loins, where it ends in a point. It is extensively +distributed in the tropical parts of South and Central America, +frequenting low swampy savannas along the banks of rivers, and the depths +of the humid forests, but is nowhere abundant. Its food consists mainly +of termites, to obtain which it opens their nests with its powerful sharp +anterior claws, and as the insects swarm to the damaged part of their +dwelling, it draws them into its mouth by means of its long, flexible, +rapidly-moving tongue covered with glutinous saliva. The Great Anteater +is quite terrestrial in its habits, being never known to climb trees, +nor does it burrow underground like the Armadillos. Though generally an +inoffensive animal, when attacked it can defend itself vigorously and +effectively with its sabre-like anterior claws. The female bears but a +single young at a birth. + +The union of the pterygoids in the middle line to prolong the narial +passage is a character found elsewhere among existing mammals only in the +next genus, in one Armadillo (_Tatusia_), and in certain Cetacea. The +contrast in length between the skull of the Great Anteater and that of +the Sloth is, as Professor Parker observes, very marked indeed; the one +being relatively the longest and the other almost the shortest in the +whole class. The small size and incomplete development of the jugal bone +in the zygomatic arch affords another striking contrast to the Sloths +(Fig. 59). + +[Illustration: FIG. 64.—The Great Anteater (_Myrmecophaga jubata_). (From +Sclater, _List of Animals in Zoological Society’s Gardens_, 1883, p. +190.)] + +_Tamandua._[101]—This genus closely resembles the last in anatomical +structure, but the head is much less elongated, the fur is short and +bristly, the tail tapering, prehensile, with the under side throughout +and the whole of the terminal portion naked and scaly. The stomach is +similar to that of _Myrmecophaga_, but with the muscular pyloric gizzard +not quite so strongly developed. There is a distinct ileo-colic valve and +a short globular cæcum. The fore foot has a very large claw on the third +toe, moderate-sized claws on the second and fourth, a very minute one on +the first, and none on the fifth, which is entirely concealed within the +skin. The hind foot has five subequal claws. Vertebræ: C 7, D 17, L 2, S +5, C 37. There are very rudimentary clavicles. + +[Illustration: FIG. 65.—Tamandua Anteater (_Tamandua tetradactyla_). From +_Proc. Zool. Soc._ 1871, pl. xliii.] + +The Tamandua (Fig. 65) is much smaller than the Great Anteater, and +differs essentially from it in its habits, being mainly arboreal. It +is an inhabitant of the dense primeval forests of South and Central +America. As different individuals vary much in their coloration, it is +possible that there may be more than one species. The usual colour is +yellowish-white, with a broad black lateral band, covering nearly the +whole of the side of the body. + +[Illustration: FIG. 66.—Cæca of the Two-toed Anteater (_Cycloturus +didactylus_). _i_, Ileum; _c_, colon.] + +_Cycloturus._[102]—The skull is much shorter even than in _Tamandua_, and +is arched considerably in the longitudinal direction. It differs from +that of the other members of the family mainly in the long canal for +the posterior nares not being closed by bone below, as the greater part +of the palatines and the pterygoids do not meet in the middle line. The +mandible has a prominent, narrow, recurved coronoid, and a well-developed +angular process; it is strongly decurved in front. Vertebræ: C 7, D 16, L +2, S 4, C 40. Ribs remarkably broad and flat. Clavicles well developed. +Manus remarkably modified, the third digit being greatly developed at the +expense of all the others, and having a stout short metacarpal and but +two phalanges, of which the most distal is large, compressed, pointed, +and much curved, and bears a very strong hook-like claw. The second digit +has the same number of phalanges, and bears a claw, but is very much more +slender than the third. The fourth is represented only by the metacarpal +and one nailless phalanx, the first and fifth only by very rudimentary +metacarpals. The pes is also completely modified into a climbing organ. +The hallux is rudimentary, consisting of a metatarsal and one phalanx, +concealed beneath the skin; but the other four toes are subequal and +much curved, with long pointed compressed claws. The tuber calcanei is +directed towards the plantar surface, and parallel with it and extending +to about double its length is a greatly elongated sesamoid ossicle. +These together support a prominent calcarine cushion, to which the nails +are opposed in climbing. Stomach pyriform, with muscular walls, but no +distinct gizzard-like portion, as in the foregoing genera. Commencement +of the colon provided with two small cæca (Fig. 66), resembling those +of many birds, narrow at the base, and rather dilated at their terminal +blind ends, and communicating with the general cavity by very minute +apertures. Tail longer than the body, tapering, bare on the under +surface, and very prehensile. Fur soft and silky. + +This genus has also but one species certainly known, the Little or +Two-toed Anteater (_C. didactylus_), an animal not larger than a Rat, of +a general yellowish-colour, and exclusively arboreal in its habits. It is +a native of the hottest parts of South and Central America. + + +_Family_ DASYPODIDÆ. + +The greater part of the skin strongly ossified. On the back and sides +the union of numerous quadrate or polygonal scutes forms a hard shield, +usually consisting of an anterior (scapular) and posterior (pelvic) +solid portion (which overhang on each side the parts of the body they +respectively cover, forming chambers into which the limbs are withdrawn), +and a variable number of rings between, connected by soft flexible skin +so as to allow of curvature of the body. The top of the head has also a +similar shield (cephalic), and the tail is usually encased in bony rings +or plates. The outer or exposed surfaces of the limbs are protected by +irregular bony scutes, not united at their margins; but the skin of the +inner surface of the limbs and under side of the body is soft, and more +or less clothed with hair. Hairs also in many species project through +apertures between the bony scutes of the back. The ossified dermal scutes +are everywhere covered by a layer of horny epidermis. Teeth numerous, +simple, of persistent growth, and usually monophyodont, but in one +genus (_Tatusia_) a succession of teeth has been observed. Zygomatic +arch of skull complete. Cervical vertebræ with extremely short, broad, +and depressed bodies. The atlas free, but the second and third, and +often several of the others, ankylosed together both by their bodies +and arches. Lumbar vertebræ with accessory zygomatic processes, and +very large metapophyses, supporting the bony carapace. Clavicles well +developed. A third trochanter on the femur. Tibia and fibula ankylosed +at their distal extremities. Fore feet with strongly developed, curved +claws, adapted for digging and scratching—three, four, or five in +number. Hind feet plantigrade, with five toes, all provided with nails. +Tongue long, pointed, and extensile, though to a less degree than in +the Anteaters. Submaxillary glands largely developed. Stomach simple. +Uterus simple. Placenta discoidal, deciduate. The brain is generally +characterised by the large size of the olfactory lobes (Fig. 57), and the +slight development of sulci on the hemispheres; the sylvian fissure being +represented only by a very open and shallow angle. From the earliest +stage of development the stapes is stirrup-shaped, thus showing a nearer +affinity to the higher mammals than is presented by the Sloths. + +The animals of this family are commonly called Armadillos, a word +of Spanish origin, having reference to their armour-like covering. +The existing species are all of small or moderate size. They are +mostly, though not universally, nocturnal in their habits, and are all +omnivorous, feeding on roots, insects, worms, reptiles, and carrion. +Armadillos are harmless and inoffensive creatures, offering no resistance +when caught, their principal means of escape from their enemies being +the extraordinary rapidity with which they can burrow in the ground, and +the tenacity with which they retain their hold in their subterranean +retreats. Notwithstanding the shortness of their limbs they can run with +great rapidity. Most of the species are esteemed good eating by the +natives of the countries in which they live. They are all inhabitants +of the open plains or the forests of the tropical and temperate +parts of South America, with the exception of one species (_Tatusia +novemcincta_), which ranges as far north as Texas. Of the existing +genera, _Chlamydophorus_ stands apart from the rest in the formation +of its external covering; but in all other respects _Tatusia_ is the +most aberrant form, exhibiting a peculiar type of structure of the fore +feet, which in all the others show modifications, though in very varying +degrees, of a single and different type. + +The reproductive organs of the _Dasypodidæ_ differ from those of the +Sloths and Armadillos in the presence of a largely developed copulating +organ in the male, and of a simple vagina of corresponding length in +the female. The testes are still abdominal, although not in the same +position; and the penis still wants both the glans and bulb. The uterus +is nearly or quite as simple as in the Sloths and Anteaters; and there is +no reason to believe that the placentation is essentially different from +that obtaining in the other groups. + +Subfamily =Chlamydophorinæ=.—In most anatomical characters, especially +the structure of the fore foot, this little group resembles the +_Dasypodinæ_; but it differs remarkably from all other known Armadillos, +living or extinct, in the peculiar modification of the dermal armour. + +_Chlamydophorus._[103]—Teeth ⁸⁄₈₋₉, subcylindrical, somewhat compressed, +moderate in size, smaller at each end (especially in front) than at +the middle of the series. Skull broad and rounded behind, pointed in +front. Muzzle subcylindrical and depressed. A conspicuous rounded, +rough prominence on the frontal bone, just before each orbit. Tympanic +prolonged into a tubular auditory meatus, curving upwards round the base +of the zygoma. Vertebræ: C 7, D 11, L 3, S 10, C 15. Upper part of head +and trunk covered with four-sided horny plates (with very small thin +ossifications beneath), forming a shield, free, and overhanging the +sides of the trunk, and attached only along the middle line of the back. +The plates are arranged in a series of distinct transverse bands, about +twenty in number between the occiput and the posterior truncated end, and +not divided into solid thoracic and pelvic shields with movable bands +between. The hinder end of the body is abruptly truncated and covered by +a vertically-placed, strong, solid, bony shield, of an oval (transversely +extended) form, covered by thin epidermic plates. This shield is firmly +ankylosed by five bony processes to the hinder part of the pelvis. +Through a notch in the middle of its lower border the tail passes out. +The latter is rather short, cylindrical in its proximal half, and +expanded and depressed or spatulate in its terminal portion, and covered +with horny plates. The dorsal surfaces of the fore and hind feet are also +covered with horny plates. The remainder of the limbs and under surface +and sides of the body beneath the overlapping lateral parts of the dorsal +shield are clothed with rather long, very soft, silky hair. Eyes and ears +very small, and concealed by the hair. Extremities short. Feet large, +each with five well-developed claws, those on the fore feet very long, +stout, and subcompressed, the structure of the digits being essentially +the same as those of _Xenurus_ and _Priodon_. Nipples two, pectoral. +Visceral anatomy closely resembling that of _Dasypus_, the cæcum being +broad, short, and bifid. + +The Pichiciago (_C. truncatus_), a small burrowing animal, about 5 inches +long, inhabits the sandy plains of the western part of the Argentine +Republic, especially the vicinity of Mendoza. Its horny covering is of +a pinkish colour, and its silky hair snow white. It is rare, and its +habits are but little known. A second species, _C. retusa_, from Bolivia, +has been described by Burmeister. It is of rather larger size, and has +the dorsal shield attached to the skin of the back as far as its edge, +instead of only along the median line. + +Subfamily =Dasypodinæ=.—Fore feet usually with all five digits developed +and with nails, though the first and fifth may be suppressed. The +first and second long and slender, with the normal number and relative +length of phalanges. The others stout, with short broad metacarpals, +and the phalanges greatly reduced in length and generally in number +by coalescence. The ungual phalanx of the third very large, that of +the others gradually diminishing to the fifth. _Dasypus_, as now +restricted, has the most normal form of manus, but the modifications so +markedly developed in all the others (and culminating in _Tolypeutes_) +are foreshadowed, as it were, in it. Ears wide apart. Mammæ one pair, +pectoral. + +_Dasypus._[104]—Teeth ⁹⁄₁₀ or ⁸⁄₉, of which the anterior in the upper +jaw is usually implanted in the premaxillary bone. The series of teeth +extends posteriorly some distance behind the anterior root of the +zygoma, almost level with the hinder edge of the palate. They are large, +subcylindrical, slightly compressed, diminishing in size towards each +end of the series; the anterior two in the mandible much smaller, and +more compressed than the others. Cranial portion of the skull broad and +depressed. Facial portion triangular, broad in front and much depressed. +Auditory bulla completely ossified, perforated on the inner side by the +carotid canal, and continued externally into an elongated bony meatus +auditorius, with its aperture directed upwards and backwards. (In all the +remaining genera of _Dasypodinæ_ the tympanic bone is a mere half ring, +loosely attached to the cranium.) Mandible with a high ascending ramus, +broad transversely-placed condyle, and high slender coronoid process. +Vertebræ: C 7, D 11-12, L 3, S 8, C 17-19. Head broad and flat above. +Muzzle obtusely pointed. Ears of moderate size or rather small, placed +laterally, far apart. Body broad and depressed. Carapace with six or +seven movable bands between the scapular and pelvic shields, each plate, +or scute, being marked by a regular ellipse formed of widely separated +punctures. Tail shorter than the body, tapering, covered with plates +forming distinct rings near the base. Fore feet with five toes; the first +much more slender than the others, and with a smaller ungual phalanx and +nail; the second, though the longest, also slender. The third, fourth, +and fifth gradually diminishing in length, all armed with very strong, +slightly curved, compressed claws, sloping away from an elevated rounded +inner border to a sharp, outer, and inferior edge. The hind foot rather +short, with all five toes armed with stout, compressed, slightly curved, +obtusely pointed claws—the third the longest, the second nearly equal to +it, the fourth the next, the first and fifth shorter, and nearly equal. + +To this genus belongs one of the best known-species of the group, the +Six-banded Armadillo or Encoubert (_D. sexcinctus_) of Brazil and +Paraguay. A very similar species, _D. villosus_, the Hairy Armadillo, +replaces it south of the Rio Plata. There are also two very small +species—_D. vellerosus_, from the Argentine Republic and North Patagonia, +and _D. minutus_ from La Plata. The latter differs from the other three +in having no tooth implanted in the premaxillary bone. Remains apparently +referable to _D. villosus_ occur in the Pleistocene cavern-deposits of +Brazil. + +_Xenurus._[105]—Teeth ⁹⁄₉ or ⁸⁄₈, of moderate size and subcylindrical. +The most posterior placed a little way behind the anterior root of the +zygoma, but far from the hinder margin of the palate. Cranium somewhat +elongated, much constricted behind the orbits, and immediately in front +of the constriction considerably dilated. Mandible slender; coronoid +process very small and sharp-pointed, sometimes obsolete. Vertebræ: C +7, D 12-13, L 3, S 10, C 18. Head broad behind. Ears rather large and +rounded, wide apart. Movable bands of carapace 12-13; the scutes being +marked by an obscurely granular sculpture. Tail considerably shorter +than the body, slender, and covered with nearly naked skin, with but a +few small, scattered, dermal bony plates, chiefly on the under surface +and near the apex. On the fore feet the first and second toes are long +and slender, with small claws and the normal number of phalanges; the +other toes have but two phalanges; the third has an immense falcate +claw; the fourth and fifth similar but smaller claws. The hind feet are +comparatively small, with five toes, bearing small, triangular, blunt +nails; the third longest, the first shortest. The best known species of +this genus, the Tatouay or Cabasson, _X. unicinctus_, is, after _Priodon +gigas_, the largest of the group. It is found, though not abundantly, in +Surinam, Brazil, and Paraguay, its remains occurring in the Pleistocene +cavern-deposits of Brazil. Others, _X. hispidus_ and _lugubris_, have +been described, but little is as yet known of them. + +_Priodon._[106]—Teeth variable in number, and generally differing on +the two sides of each jaw, usually from 20 to 25 on each side above and +below, so that as many as 100 may be present altogether; but as life +advances the anterior teeth fall out, and all traces of their alveoli +disappear. The series extends as far back as the hinder edge of the +anterior root of the zygoma. The teeth are all very small; those in the +anterior half of each series being strongly compressed, with flat sides +and a straight free edge; the posterior ones are more nearly cylindrical, +with flat truncated, free surfaces. Vertebræ: C 7, D 12, L 3, S 10, C +23. Head small, elongated, conical. Ears moderate, ovate. Carapace with +12-13 movable bands. Tail nearly equal to the body in length, gradually +tapering, closely covered with quadrangular scales, arranged in a +quincunx pattern. Fore feet with five toes, formed on the same plan as +those of _Xenurus_, but with the claw of the third of still greater size, +and that of each of the others, especially the fifth, proportionately +reduced. Hind foot short and rounded, with five very short toes, with +short, broad, flat, obtuse nails. The only known species, the Great +Armadillo (_P. gigas_), is by far the largest of existing members of the +family, measuring rather more than 3 feet from the tip of the nose to the +root of the tail, the tail being about 20 inches long. It inhabits the +forests of Surinam and Brazil. The powerful falcate claws of its fore +feet enable it to dig with great facility. Its food consists chiefly +of termites and other insects, but it is said to attack and uproot +newly-made graves for the purpose of devouring the flesh of the bodies +contained in them. + +_Tolypeutes._[107]—Teeth ⁹⁄₉ or ⁸⁄₉, rather large in proportion to the +size of the skull, the hinder end of the series reaching nearly to the +posterior margin of the palate. Vertebræ: C 7, D 11, L 3, S 12, C 13. +Ears placed low on the sides of the head, rather large, broadly ovate. +Carapace with its scapular and pelvic shields very free at the sides of +the body, forming large chambers into which the limbs can be readily +withdrawn. Only three movable bands; sculpture of scutes in the form +of subconcentrically arranged granules. Tail short, conical, covered +with large bony tubercles. The fore feet formed on the same type as in +the last genus, but the peculiarities carried out to a still greater +extent. The claw of the third toe is very long and falcate, the first and +fifth greatly reduced and sometimes wanting. On the hind foot the three +middle toes have broad, flat, subequal nails, forming together a kind of +tripartite hoof; the first and fifth much shorter, with more compressed +nails. + +The Armadillos of this genus have the power of rolling themselves up into +a perfect ball, the shield on the top of the head and the tuberculated +dorsal surface of the tail exactly fitting into and filling up the +apertures left by the notches at either end of the carapace. This +appears to be their usual means of defence when frightened or surprised, +as they do not burrow like the other species. They run very quickly, +with a very peculiar gait, only the tips of the claws of the fore feet +touching the ground. Three species are described:—_T. tricinctus_, the +Apar; _T. conurus_, the Matico; and _T. muriei_. Remains apparently +referable to _T. conurus_ are of not uncommon occurrence in the Brazilian +cavern-deposits. + +Subfamily =Tatusiinæ=.—This group contains but one genus, _Tatusia_.[108] +Teeth ⁸⁄₈ or ⁷⁄₇, very small subcylindrical. The first and second +subcompressed, the last considerably smaller than the others. They +present the remarkable peculiarity (elsewhere found among Edentates, +so far as is yet known, only in _Orycteropus_) of all being, with the +exception of the last, preceded by two-rooted milk teeth, which are not +changed until the animal has nearly attained its full size. Vertebræ: +C 7, D 9-11, L 5, S 8, C 20-27. Head narrow, with a long, narrow, +subcylindrical, obliquely-truncated snout; pterygoids meeting in the +middle line below the nasal passage. Ears rather large, ovate, and +erect, placed close together on the occiput. Carapace with seven to nine +distinct movable bands; sculpture on scutes consisting of pits arranged +in a V-shape. Body generally elongated and narrow. Tail moderate or long, +gradually tapering; its dermal scutes forming very distinct rings for +the greater part of its length. Fore feet with four visible toes, and +a concealed clawless rudiment of the fifth. Claws all long, slightly +curved, and very slender, the third and fourth subequal and alike, the +first and fourth much shorter. Hind feet with five toes, all armed with +strong, slightly curved, conical, obtusely-pointed nails. The third +longest, then the second and fourth; the first and fifth much shorter +than the others. + +[Illustration: FIG. 67.—The Peba Armadillo (_Tatusia novemcincta_).] + +This genus differs from all the other Armadillos in having a pair of +inguinal mammæ, in addition to the usual pectoral pair, and in producing +a large number (four to ten) of young at a birth, all the others having +usually but one or two. + +The Peba Armadillo, _T. novemcincta_ (Fig. 67), is a well-known species, +having an extensive range from Texas to Paraguay. It is replaced in the +more southern regions of South America by a smaller species, with shorter +tail, the Mulita (_T. hybrida_), so called from the resemblance of its +head and ears to those of a mule. _T. kappleri_ is a large species from +Surinam. + +A rare Armadillo from Peru described under the names of _Cryptophractus +pilosus_ and _Praopus hirsutus_, but which evidently belongs to +_Tatusia_, is of some interest owing to the thick coat of hair with +which it is covered. This animal appears to be closely allied to _T. +novemcincta_, from which it mainly differs by having the whole of the +carapace covered with a thick coating of light brown, fine, but rather +stiff hair, about an inch and a half in length. Similar hair is found +on the cheeks, the proximal portions of the limbs, and (although less +abundantly and shorter) on the under surface of the body. The cephalic +shield, snout, feet, and the tail, with the exception of the root, are +bare. The coating of hair on the back and sides completely conceals +the carapace, except near the margin of the scapular region; but by +separating the hairs the bands and scutes are rendered visible.[109] + +In the Pleistocene cavern-deposits of Brazil have been found remains +of _T. novemcincta_, and also of _T. punctata_, which appears to be an +extinct form nearly allied to _T. kappleri_, but of somewhat larger size. + +_Extinct genera._—In addition to remains referable to existing genera, +the above-mentioned deposits have also yielded evidence of the former +existence of extinct generic types of Armadillos, some of which attained +very large dimensions. Of these _Eutatus_ was a large form distinguished +from all existing genera by the circumstance that the whole of the +carapace was composed of movable bands, which were thirty-three in +number. _Dasypotherium_ was a still larger form, furnished with eight +teeth, of which the second seems to have been larger than the others; +this genus is regarded as connecting the modern Armadillos with the next +one. The gigantic _Chlamydotherium_, the scutes of which are common in +the Brazilian caves, is considered to have been as large as a Rhinoceros; +the carapace has several movable bands, but the teeth approximate in +structure to those of the next family, so that the genus tends to connect +the Armadillos with the Glyptodonts. + + +_Family_ GLYPTODONTIDÆ. + +[Illustration: FIG. 68.—Tooth of _Glyptodon_ from the side, and from the +grinding surface. (After Owen.)] + +In the Pleistocene cavern-deposits of Brazil, but still more abundantly +in the fluviatile deposits which cover the country in the neighbourhood +of Buenos Ayres, are found the remains of some of the most remarkable +forms of mammals yet discovered, the Glyptodonts, which may be regarded +as forming a separate extinct family. They differ from the existing +_Dasypodidæ_ in their large size, and in having the carapace composed of +a solid piece (formed by the union of a multitude of bony dermal scutes) +without any movable rings, and in usually having also a ventral piece or +plastron. The facial portion of the skull is very short. A long process +of the maxillary bone descends from the anterior part of the zygomatic +arch. The ascending ramus of the mandible is remarkably high. The teeth +are ⁸⁄₈ in the known species, all much alike, having two deep grooves or +flutings on each side, so as to divide them into three nearly distinct +lobes (Fig. 68). The vertebral column is almost entirely ankylosed into +a solid tube, and there is a complex joint at the base of the neck, to +allow of the head being retracted within the carapace. The limbs are +very strong, and the feet short and broad, resembling externally those +of an elephant or tortoise. This family is mainly characteristic of the +southern half of the American continent, but some species of the type +genus ranged into Texas and Mexico. Many species of the family have +been described and figured, especially by Burmeister (in the _Annales +del Museo publico de Buenos Aires_), among which the following may be +noticed. _Hoplophorus_ is characterised by the sculptured and frequently +thin scutes of the carapace, those of the periphery being flat, and +not raised into prominences. The caudal sheath has several overlapping +movable rings at the base, and ends in a long subcylindrical terminal +tube similar to the one represented with the carapace of _Glyptodon_ +in Fig. 69, which in all probability really belongs to the genus under +consideration. Each foot has four complete digits, and the humerus has +an entepicondylar foramen. Most of the species are of medium size. Part +of a caudal tube from Uruguay described as _Eleutherocercus_ indicates, +however, a much larger allied form, in which the tail appears to have +had a number of stout bristles protruding from the joints between the +scutes. _Panochthus_ comprises very large Glyptodonts, distinguished by +the great thickness of the scutes of the carapace, which are ornamented +with tubercles. The termination of the caudal sheath forms a tube bearing +large radiated tubercles. _Euryurus_ is distinguished by the radiate +sculpture of the scutes of the carapace. _Dœdicurus_, of which one +species was about twelve feet in length, also has a rugose sculpture +on the carapace; but the termination of the caudal tube is expanded +into a club-like shape, flattened from above downwards, and covered +with tubercles mingled with a few large radiate discs, which, as in +_Panochthus_, probably carried horny spines in the living condition. The +typical genus _Glyptodon_ has each scute of the carapace ornamented with +a rosette-like sculpture, the peripheral scutes being raised into conical +prominences (Fig. 69). The caudal sheath, instead of being like the one +represented in the figure, was entirely composed of a series of movable +rings, ornamented with large tubercles. The manus had five digits, and +the pes four; and there was an entepicondylar foramen to the humerus. A +species of this genus, which attained very large dimensions, was made the +type of _Schistopleurum_, on the supposition that the tail of _Glyptodon_ +was of the type represented in Fig. 69. The genus _Thoracophorus_, +of the Pleistocene of South America, as well as _Carioderma_, of the +Pliocene of Texas, differ from all the preceding in having the scutes of +the carapace in the form of disconnected nodules. Glyptodonts also occur +in South American beds of earlier age than the Pleistocene, some of these +forms having enamel bands on the teeth. “Why such a form as the Glyptodon +should have failed to keep his ground is,” as the late Professor W. K. +Parker remarks, “a great mystery; nature seems to have built him, as Rome +was built, for eternity.” + +[Illustration: FIG. 69.—_Glyptodon clavipes_ (Pleistocene, South +America). From Owen. The tail is incorrectly restored, and it is probable +that the figured portion belongs to _Hoplophorus_. The left lower corner +shows an upper and a lower view of the skull, and the right a section of +the caudal sheath.] + + +_Family_ MANIDÆ. + +Covered externally (except the under surface of the body and inside +of the limbs) with large imbricated horny scales, and scattered +hairs growing in the intervals. No teeth. Tongue long, vermiform, +and protractile. No accessory articular processes to the lumbar +vertebræ, but the anterior zygapophyses largely developed and deeply +concave, completely embracing the semicylindrical surfaces of the +posterior zygapophyses. Limbs short, with five complete digits on each +foot. Scaphoid and lunar bones of carpus united. Uterus bicornuate. +Placenta diffused and non-deciduate. All the existing forms belong to +the Ethiopian and Oriental regions of the Old World. The absence of +additional articular processes to the lumbar vertebræ is a character in +which this and the following family differ from all the preceding forms. + +_Manis._[110]—Skull somewhat of the form of an elongated cone, with the +small end turned forwards; very smooth and free from crests and ridges. +No distinction between the orbits and temporal fossæ. The zygomatic arch +usually incomplete, owing to the absence of the jugal bone. No distinct +lachrymal bone. Palate long and narrow. The pterygoids extend backwards +as far as the tympanics, but do not meet in the middle line below. +Tympanic ankylosed to the surrounding bones, and more or less bullate, +but not produced into a tubular auditory meatus. Rami of mandible very +slender and straight, without any angle or coronoid process. From near +the anterior extremity of the upper edge a sharp, conical, tooth-like +process projects upwards and outwards. No clavicles. No third trochanter +to the femur. Ungual phalanges bifid at their terminations. Caudal +vertebræ with very long, strong transverse processes and numerous +chevron bones. Tongue long, vermiform, flattened towards the tip; its +retractor or sterno-glossal muscles arising from the hinder extremity +of the immensely prolonged ensiform cartilage of the sternum. Stomach +with thick lining membrane and muscular walls, and a special gland near +the middle of the great curvature, consisting of a mass of complex +secreting follicles, the ducts of which terminate in a common orifice. +No cæcum. A gall-bladder. Head small, depressed, narrow, pointed in +front, with a very small mouth-opening. Eyes and pinna of ear very small. +Body elongated, narrow. Tail more or less elongated, convex above, +flat underneath. The whole of the upper surface of the head, the upper +surface and sides of the body, the whole of the tail, and the outer sides +of the extremities covered with large, overlapping, horny scales, but +usually with a few stiff hairs growing between and projecting beyond +them. The sides and under surface of the head, the under surface of the +body, and the inner sides of the limbs without scales, but with a rather +scanty covering of hair. Limbs short. In walking the dorsal surface and +outer sides of the phalanges of the two outer digits of the front feet +alone rest on the ground, the points of the nails turning upwards and +inwards. The third toe the longest, with a powerful compressed curved +claw; the second and fourth with similar but smaller claws, that of the +pollex often almost rudimentary. Hind feet plantigrade, with the hallux +very short, and the four other toes subequal, with moderate, curved, +subcompressed nails. + +The reproductive organs of _Manis_ are of a totally different type from +those of the families already noticed. The testes lie in the inguinal +canal; and the penis is external and well developed. The uterus is +truly bicornuate, the vagina not divided, and the placenta diffused and +non-deciduate. All the organs and fœtal membranes are, indeed, formed +very much on the plan of those of the Ungulates, without any trace of the +special peculiarities obtaining in the typical American Edentates. + +The animals of this genus, which includes all the existing forms, are +called Pangolins or Scaly Anteaters, and are all of small or moderate +size, terrestrial and burrowing, and feed mainly on termites. Several +of them can climb trees. Their length varies from 1 to 5 feet. They can +roll themselves up in a ball when in danger. Their peculiar elongated +form, short limbs, long, gradually-tapering tail, and scaly covering give +them on a superficial inspection more the appearance of reptiles than of +mammals. The species are not numerous, and may be divided into two groups +distinguished by a few not very important external characters; these +groups also coinciding with the present geographical distribution of the +genus. These two groups, according to Mr. O. Thomas, may be distinguished +as follows. + +The Asiatic pangolins are characterised by having the central series of +body-scales continued quite to the extreme end of the tail, by having +many isolated hairs growing up between the scales of the back, and by +their small external ears. They all have a small naked spot beneath +the tip of the tail, which is said to be of service as an organ of +touch. There are three species, viz. _Manis javanica_, ranging from +Burma, through Malacca and Java, to Borneo; _M. aurita_, found in China, +Formosa, and Nipal; and the common Indian Pangolin, _M. pentadactyla_, +distributed over the whole of India and Ceylon. The African species have +the central series of scales suddenly interrupted and breaking into +two at a point about 2 or 3 inches from the tip of the tail; they have +no hair between the scales, and no external ear-conch. The following +are the four species belonging to this group:—the Long-tailed Pangolin +(_M. macrura_), which has a tail nearly twice as long as its body, and +containing as many as forty-nine caudal vertebræ, being the largest +number known among mammals; the White-bellied Pangolin (_M. tricuspis_), +Fig. 70, closely allied to the last, but with longer and tricuspid +scales, and white belly hairs. These two, like the Indian species, have +a naked spot beneath the tail tip, a character probably correlated with +the power of climbing, and they are, moreover, peculiar in having the +outer sides of their fore legs clothed with hair, all the other species +being scaly there as elsewhere. Lastly, the Short-tailed and the Giant +Pangolins (_M. temmincki_ and _gigantea_), both of which have their +tails covered entirely with scales, and evidently never take to arboreal +habits. All the four species of the second group are found in the West +African region, one only, _M. temmincki_, extending also into south and +eastern equatorial Africa. + +[Illustration: FIG. 70.—The White-bellied Pangolin (_Manis tricuspis_).] + +According to Professor W. K. Parker,[111] who remarks upon the peculiarly +aberrant nature of the group, the horny scales of the Pangolins really +consist of cemented hairs. This writer states that “in the early embryo +lozenge-shaped tracts of skin are seen all over its body, with lines of +thinner cuticle between. Under the microscope, sections of these thicker +tracts show that they are composed of fine hairs, cemented together by a +copious growth of epidermic cells; here and there larger hairs are seen, +but these fail to reach the surface, turning again towards the inside, +like nails driven into wood that is too hard for their points.” + +The same author also observes[112] that there are occasional instances of +the presence of eight cervical vertebræ in the Pangolins—a feature which +has been considered to indicate some former genetic connection between +this family and the Sloths. + +The following account of the habits of _Manis tricuspis_ is given by Mr. +L. Fraser in his _Zoologia Typica_:— + +“During my short residence at Fernando Po I succeeded in procuring two +living specimens of this animal. The individuals, judging from the bones, +were evidently not adult; the largest measured 30 inches in length, +of which the head and body were 12 inches and the tail 18 inches. I +kept them alive for about a week at Fernando Po, and allowed them the +range of a room, where they fed upon a small black ant, which is very +abundant and troublesome in the houses and elsewhere. Even when first +procured they displayed little or no fear, but continued to climb about +the room without noticing my occasional entrance. They would climb up +the somewhat roughly hewn square posts which supported the building +with great facility, and upon reaching the ceiling would return head +foremost; sometimes they would roll themselves up into a ball and throw +themselves down, and apparently without experiencing any inconvenience +from the fall, which was in a measure broken upon reaching the ground by +the semi-yielding scales, which were thrown into an erect position by the +curve of the body of the animal. In climbing, the tail, with its strongly +pointed scales beneath, was used to assist the feet; and the grasp of +the hind feet, assisted by the tail, was so powerful that the animal +would throw the body back (when on the post) into a horizontal position, +and sway itself to and fro, apparently taking pleasure in this kind of +exercise. It always slept with the body rolled up; and when in this +position in a corner of the building, owing to the position and strength +of the scales, and the power of the limbs combined, I found it impossible +to remove the animal against its will, the points of the scales being +inserted into every little notch and hollow of the surrounding objects. +The eyes are very dark hazel, and very prominent. The colonial name for +this species of _Manis_ is ‘Attadillo,’ and it is called by the Boobies, +the natives of the island, ‘Gahlah.’ The flesh is said to be exceedingly +good eating, and is in great request among the natives.” + +The Indian species is said to live in pairs, and to give birth to one or +two young at a time in the spring. Their burrow reaches a depth of some +twelve feet, and terminates in a large chamber, which may be as much as +six feet in diameter. A faint hiss appears to be the only sound emitted +by these animals. + +Remains of a large species of _Manis_, which are indistinguishable from +the corresponding bones of the existing West African _M. gigantea_, +are found fossil in cave-deposits in the Karnul district of Madras. +This is one among several instances of the close connection between the +Pleistocene and Pliocene mammalian fauna of India with the existing +African fauna. + +_Palæomanis._[113]—The lower Pliocene deposits of the Isle of Samos, in +the Turkish Archipelago, have yielded remains of a Pangolin fully three +times the dimensions of _M. gigantea_, upon the evidence of which the +genus _Palæomanis_ has been established. + + +_Family_ ORYCTEROPODIDÆ + +External surface scantily covered with bristle-like hairs. Teeth +numerous, apparently heterodont, diphyodont, and of peculiar and complex +structure, being traversed by a number of parallel vertical pulp-canals. +Lumbar vertebræ with no accessory zygapophyses. Femur with a third +trochanter. Fore feet without pollex, but all the other digits well +developed, with strong moderate-sized nails, suited to digging, the +plantar surfaces of which rest on the ground in walking. Hind feet with +five subequal toes. Mouth elongated and tubular. Tongue subvermiform. +Uterus bicornuate. Placenta broadly zonular. Feeding on animal +substances. Terrestrial and fossorial in habits. Now mainly limited to +the Ethiopian region. + +_Orycteropus._[114]—The total number of permanent teeth appears to be +from eight to ten in each side of the upper, and eight in the lower jaw; +but they are never all in place at one time, as the small interior teeth +are shed before the series is completed behind. In the adult they number +usually five on each side above and below, of which the first two are +simple and compressed, the next two larger and longitudinally grooved at +the sides, the most posterior simple and cylindrical. The last three in +either jaw having no milk-predecessors, may be regarded as true molars. +The structure of all these teeth is quite peculiar among mammals, though +resembling that of some fishes. Their summits are rounded before they are +worn; their bases do not taper to a root, but are evenly truncated and +continually growing. Each tooth is made up of an aggregation of parallel +dental systems, having a slender pulp-cavity in the centre, from which +the dentinal tubes radiate outwards, and being closely packed together +each system assumes a polygonal outline as seen in transverse section. +The small anterior teeth have milk-predecessors which are fully noticed +below. Skull moderately elongated. The facial portion subcylindrical +and slightly tapering. The zygoma complete and slender. The palate ends +posteriorly in the thickened transverse border of the palatines, and is +not continued back by the pterygoids. The tympanic is annular, and not +ankylosed to the surrounding bones. The mandible is slender anteriorly, +but rises high posteriorly, with a slender recurved coronoid, and an +ascending pointed process on the hinder edge below the condyle, which +is small, oval, and looks as much forwards as upwards. Vertebræ: C 7, +D 13, L 8, S 6, C 27. The large number of lumbar vertebræ is peculiar +among Edentates. Tongue less vermiform than in _Myrmecophaga_, being +thick and fleshy at the base, and gradually tapering to the apex. The +salivary apparatus is developed much in the same manner as in that genus, +but the duct of the submaxillary gland has no reservoir. The stomach +consists of a large subglobular cardiac portion, with a very thick, soft, +and corrugated lining membrane, and a smaller muscular, pyloric part, +with a comparatively thin and smooth lining. There is a very distinct +ileo-cæcal valve, and a considerable-sized cæcum; also a gall-bladder. +Head elongated, with a tubular snout, terminal nostrils, and small +mouth-opening. Ears large, pointed, erect. Tail nearly as long as the +body, cylindrical, very thick at the base, tapering to the extremity. + +The reproductive organs and placentation of _Orycteropus_ are formed upon +a principle unknown in the more typical Edentates, or, in combination, +in any other mammals. Thus the testes, in the one described example, +were inguinal, but appeared to descend, at all events temporarily, into +a scrotum; but the penis is scarcely larger than that of the Great +Anteater. The uterus is still more fully bicornuate than in _Manis_, +with its two lateral chambers opening separately into the vagina, as in +certain Rodents. The placenta is broadly zonary, but it is not known +whether it is deciduate or not. It might readily be derived from the +diffused placenta of _Manis_ by the abortion of the fœtal villi at the +two poles of the ovum. + +The _Orycteropodidæ_ have long been regarded as widely different from +other Edentates, their presumed affinity with the _Manidæ_ being more or +less problematical; but the discovery recently made by Mr. O. Thomas[115] +that they have a milk-dentition still further emphasises their aberrant +nature. According to this observer, it appears that there are normally +no less than seven milk-teeth in the upper jaw, the hindmost of which is +far larger than the others, having a rudimentary crown, and a distinct +anterior and posterior root. The other milk-teeth are styliform, the +four anterior ones being very minute, and separated from one another +by equal intervals; the foremost of all is situated immediately behind +the premaxillo-maxillary suture. In the mandible only four milk-teeth +have hitherto been detected, of which the hindmost has the comparatively +complex form found in the corresponding upper tooth. None of these +milk-teeth appear, however, to cut the gum, so that the whole set is +entirely functionless. Under the microscope these milk-teeth show signs +of possessing a commencement of the remarkable histological structure +found in the permanent teeth. + +Mr. Thomas remarks that since “the three large posterior teeth of +_Orycteropus_, already distinguished by their more molariform shape, do +not have milk-predecessors, while all the small teeth anterior to them +do, and in addition the last milk-tooth is markedly different from those +in front of it, we ought apparently no longer to look upon this animal as +an homodont, but instead to consider it as an originally heterodont form +in which the incisors and canines have been suppressed to allow free play +to the mobile vermiform tongue. + +“But important as a knowledge of the presence of a milk-dentition in +_Orycteropus_ is, it does not at present render any easier the difficult +questions as to the phylogeny and systematic position of that animal. +Although called an Edentate, it has always been recognised as possessing +many characters exceedingly different from those of the typical American +members of the order. It has in fact been placed with them rather on +account of the inconvenience of forming a special order for its reception +than because of its real relationship to them. Now, as they are either +altogether toothless, or else homodont and monophyodont (apart from the +remarkable exception of _Tatusia_), it seems more than ever incorrect +to unite with them the solitary member of the Tubulidentata, toothed, +heterodont, and diphyodont, and differing from them in addition by +its placentation, the anatomy of its reproductive organs, the minute +structure of its teeth, and the general characters of its skeleton. + +“But if _Orycteropus_ is not genetically a near relation of the +Edentates, we are wholly in the dark as to what other mammals it is +allied to, and I think it would be premature to hazard a guess on the +subject. Whether even it has any special connection with _Manis_ is +a point about which there is the greatest doubt, and unfortunately +we are as yet absolutely without any palæontological knowledge of +the extinct allies of either. _Macrotherium_ even, usually supposed +from the structure of its phalangeal bones, to be related to _Manis_, +has lately proved to have the teeth and vertebræ of a perissodactyle +Ungulate, and one could not dare to suggest that ancestors of _Manis_, +or _Orycteropus_ were to be sought in that direction. Lastly, as the +numerous fossil American Edentates do not show the slightest tendency +to an approximation towards the Old World forms, we are furnished with +an additional reason for insisting on the radical distinctness of the +latter, whose phylogeny must therefore for the present remain one of the +many unsolved zoological problems.” + +The Aard-Varks (Earth-Pigs) as these creatures are commonly termed, +from the name bestowed on them by the Dutch Boers of the Cape, are of +nocturnal habits, sleeping during the day in their burrows, which are +usually found in the neighbourhood of the tall hills or mounds made by +termites. Indeed, wherever these hills are abundant it is stated there +is a good chance of finding an Aard-Vark, the food of these animals +consisting almost exclusively of termites and ants. + +Two existing species are recognised, namely the Cape Aard-Vark (_O. +afra_) from South Africa, and another (_O. æthiopicus_) from the +north-eastern parts of Africa, ranging into Egypt. An extinct species +has been described from the Lower Pliocene of the Isle of Samos, in the +Turkish Archipelago, differing from the existing forms by the larger +proportionate size of the lateral metatarsals. + + _Bibliography of Edentata._—No general work on the order has + been published since that of Rapp (_Anat. Untersuchungen über + die Edentaten_, 2d ed. 1852). Among numerous memoirs on special + groups the following may be cited:—_Myrmecophagidæ_:—R. Owen, + “Anatomy of Great Anteater,” _Trans. Zool. Soc._ vol. iv.; G. + Pouchet, _Mém. sur le Grand Fourmilier_, 1874; W. A. Forbes, + “Anat. of Great Anteater,” _Proc. Zool. Soc._ 1882, p. 287. + _Megatheriidæ_:—R. Owen, _Extinct Gigantic Sloth (Mylodon + Robustus)_, 1842; Id., “On the Megatherium,” _Phil. Trans._ + 1851-56; J. Leidy, “Extinct Sloth-tribe of North America,” + _Smithsonian Contrib. to Knowledge_, vii. 1855; H. Burmeister, + _Description de la République Argentine_, t. iii. Mammifères, + 1879,—which contains full references to various memoirs by + Owen, Gervais, Reinhardt, and others. _Glyptodontidæ_:—Owen, + _Catalogue of Fossil Mammals, Mus. Roy. Coll. Surgeons_, 1845; + T. H. Huxley, “Osteol. of Glyptodon,” _Phil. Trans._ 1865; H. + Burmeister, _Annales del Museo Publico de Buenos Aires_, and + _Descript. de la République Argentine_, 1879; H. Gervais and F. + Ameghino, _Les Mammifères Fossiles de l’Amérique Méridionale_, + Paris, 1880,—which also contains a list of all the S. American + Edentates described at that date. _Dasypodidæ_:—J. Murie, + “Anatomy of _Tolypeutes_,” _Trans. Linn. Soc._ vol. xxx. 1874; + A. H. Garrod, _Proc. Zool. Soc._ 1878. For Placentation of + Edentates see W. Turner, _Trans. Roy. Soc. Edin._ xxvii. (1873) + p. 72, and _Journ. Anat. and Physiol._ vols. viii. and x.; A. + Milne-Edwards, _Ann. Sciences Nat._ [6] viii. p. 1; and for + brain, P. Gervais, “Formes cérébrales des Edentés,” _Nouv. + Arch. du Muséum_, tom. v.; W. Turner, _Jour. Anatomy_, i. 313 + (1867). For the dentition of _Orycteropus_ see O. Thomas, “A + Milk Dentition in _Orycteropus_,” _Proc. Roy. Soc._ vol. xlvii. + p. 246 (1890). Fuller observations on the mutual relations of + the various families are given by W. H. Flower, “On the Mutual + Affinities of the Animals composing the Order Edentata,” _Proc. + Zool. Soc._ 1882, p. 358. + + + + +CHAPTER VIII + +THE ORDERS SIRENIA AND CETACEA + + +_Order_ SIRENIA. + +The purely aquatic habits and fish-like form of the animals of this +order caused them to be formerly confounded with the Cetacea, but a more +intimate knowledge of their structure has shown that they really belong +to a widely different type of the mammalian class. + +The head is rounded and not disproportionate in size as compared with +the trunk, from which it is scarcely separated by any externally visible +constriction or neck. Nostrils valvular, separate, and placed above +the fore part of the obtuse truncated muzzle. Eyes very small, with +imperfectly formed eyelids, capable, however, of contraction, and with +a well-developed nictitating membrane. Ear without any pinna. Mouth +of small or moderate size, with tumid lips beset with stiff bristles. +General form of the body depressed, fusiform. No dorsal fin. Tail +flattened and horizontally expanded. Fore limbs paddle-shaped, the digits +being enveloped in a common cutaneous covering, on which rudiments of +nails are sometimes present. No trace of hind limbs in existing forms. +External surface covered with a tough, finely wrinkled, or very rugose +skin, naked, or with fine hairs sparsely scattered over it. + +The skeleton is remarkable for the massiveness and density of most of +the bones of which it is composed, especially the skull and ribs, which +must add to the specific gravity of these slow-moving animals, and +aid in keeping them to the bottom of the shallow waters in which they +dwell, while feeding on aquatic vegetables. The skull presents many +peculiarities, among which may be indicated the large size and backward +position of the anterior narial aperture, a further modification of that +met with in the Tapirs among Ungulates, and presenting some approach to +that so characteristic of the Cetacea. The nasal bones are generally +absent in the recent forms, or are only found in a most rudimentary +condition, attached to the edge of the frontals, far away from the +middle line; but in some at least of the extinct species these bones, +though small in size, are normal in situation and relations. In very few +other respects does the skull present any resemblance to that of the +Cetacea. In the spinal column of existing forms none of the vertebræ are +united together to form a sacrum, and the flat ends of the bodies do +not ossify separately, so as to form disc-like epiphyses in the young +state, as in nearly all other mammals; traces of epiphyses have, however, +been recently detected in _Manatus_, and they were fully developed in +_Halitherium_ and other fossil forms. The anterior caudal vertebræ have +well-developed chevron bones. In one genus (_Manatus_) there are only six +cervical vertebræ. There are no clavicles. The humerus has a small but +distinct trochlear articulation at the elbow-joint. The two bones of the +forearm are about equally developed, and generally ankylosed together +at both extremities. The carpus is short and broad, and the digits five +in number, with moderately elongated and flattened phalanges, which are +never increased in number beyond the limit usual in the Mammalia. The +pelvis is extremely rudimentary, consisting of a pair of bones suspended +at some distance from the vertebral column. In no existing species is +there any trace of a hind limb, but in the extinct _Halitherium_ an +acetabular depression and rudimentary femur have been discovered. + +Two kinds of teeth, incisors and molars, separated by a wide interval, +are generally present. The former may be developed into tusks in +the upper jaw, or may be quite rudimentary. The molars vary much in +character. In one genus (_Rhytina_) no teeth of any kind are present, at +least in the adult. Some fossil forms show a more decidedly heterodont +dentition, while _Halitherium_ has milk-teeth, of which no traces have +been observed in the recent genera. In all recent types the anterior part +of the palate, and a corresponding surface on the prolonged symphysis +of the lower jaw, are covered with rough horny plates of peculiar +structure, which doubtless assist in mastication. The tongue is small +and fixed in position, with a surface resembling that of the plates just +spoken of. The salivary glands are largely developed. The stomach is +compound, being divided by a valvular constriction into two principal +cavities, the first of which is provided with a singular glandular pouch +near the cardiac end, and the second usually with a pair of elongated, +conical, cæcal sacs or diverticula. The intestinal canal is long, and +has very muscular walls. There is a cæcum, either simple, conical, and +with extremely thick walls, as in _Halicore_, or bifid, as in _Manatus_. +The heart is broad and flat, with its apex deeply cleft between the +ventricles. The principal arteries form very extensive and complex retia +mirabilia. The lungs are remarkably long and narrow, as, owing to the +very oblique position of the diaphragm, the thoracic cavity extends far +back over the abdomen. The epiglottis and arytenoid cartilages of the +larynx do not form a tubular prolongation as in the Cetacea, so that the +epiglottis is not intranarial. The brain is of comparatively small size, +and the convolutions on the surface of the cerebrum are few and shallow. +The kidneys are simple. The testes abdominal. The uterus is bicornuate. +The placenta (in the Dugong) is non-deciduate and zonary. The umbilical +vesicle disappears early. The mammæ are two, and pectoral, or rather +postaxillary in position. + +The Sirenia pass their whole life in the water, being denizens of +shallow bays, estuaries, lagoons, and large rivers, but, unlike the +Cetacea, are not met with in the high seas, far away from the shore. +Their food consists entirely of aquatic plants, either marine algæ or +freshwater grasses, upon which they browse beneath the surface, as the +terrestrial herbivorous mammals do upon the green pastures on shore. +They are generally gregarious, slow and inactive in their movements, +mild, inoffensive, and apparently unintelligent in disposition. +Though occasionally found stranded by the tide or waves, there is no +satisfactory evidence that they voluntarily leave the water to bask or +feed on the shore. The habit of the Dugong of raising its round head +out of the water, and carrying its young under the fore fin, seems to +have given rise, among the imaginative early voyagers in the Indian +Ocean, to the legendary beings, half human and half fish, in allusion +to which the name Sirenia was bestowed by Illiger on the order, though +certainly the face of a Dugong, when closely inspected, does not bear the +slightest resemblance to that of the mermaid of romance. The species now +existing are very few, and there is reason to believe that the time is +not far distant when they will all become extinct. One species, _Rhytina +stelleri_, of the North Pacific, was totally exterminated through the +agency of man during the last century; and the others, being valuable for +their flesh as food, for their hides, and especially for the oil obtained +from the thick layer of fat which lies immediately beneath their skin, +rapidly diminish in numbers as civilised populations occupy the regions +forming their natural habitat. The surviving species are confined to the +tropical regions of the shores of both sides of the Atlantic and the +great rivers which empty themselves into that ocean, and to the coasts of +the Indian Ocean from the Red Sea to North Australia. In the Miocene and +early Pliocene epoch Sirenians abounded in the seas of Europe, and their +remains have been found in deposits of corresponding periods in North +America. Evidence has also been discovered of the existence of an animal +of this group in the seas at the bottom of which the Eocene nummulitic +limestone mountain ranges of Egypt were deposited. + +The existing genera present such well-marked distinguishing characters +that it is on the whole convenient to place them in separate families, +although, as in so many similar cases, our knowledge of the extinct +forms, imperfect as it is, goes far to bridge over the distinction +between them. + + +_Family_ MANATIDÆ. + +The characters of this and the two following families may be conveniently +included under the heading of the single genus by which they are +respectively represented. + +_Manatus._[116]—Incisors ²⁄₂, rudimentary, concealed beneath the horny +oral plates, and disappearing before maturity. Molars ¹¹⁄₁₁, but rarely +more than ⁶⁄₆ present at one time, the anterior teeth falling before the +posterior come into use; similar in characters from beginning to end of +the series; with square, enamelled crowns, the grinding surface raised +into tuberculated transverse ridges. The upper teeth with two ridges +and three roots, the lower teeth with an additional (posterior) ridge, +or talon, and two roots. The cervical vertebræ present the remarkable +anomaly of being reduced to six in number, the usual vertebral formula +being C 6, D 17, L 2, and C 23-25. Rostrum of the skull, formed by +the union of the premaxillæ in front of the anterior narial aperture, +shorter than the length of the aperture and scarcely deflected from +the basicranial axis; premaxillæ and mandibular symphysis not markedly +deflected (Fig. 72). Tail entire, rounded, or shovel-shaped. Rudimentary +nails on the fore limbs. Cæcum bifid. Habitat the shores of, and the +great rivers which empty themselves into, the Atlantic within the +tropics. These animals are rather fluviatile than marine, ascending large +rivers almost to their sources. + +The Manatee may be selected for a somewhat full description, as being one +of the best known representatives of this very remarkable order. + +The name _Manati_ was apparently first applied to this animal by the +early Spanish colonists of the West Indies, in allusion to the hand-like +use which it frequently makes of its fore limbs; by English writers from +the time of Dampier (who gives a good account of its habits) downwards +it has been generally spelt “Manatee.” It was placed by Linnæus in his +heterogeneous genus _Trichechus_, but Storr’s name _Manatus_ is now +generally accepted for it by zoologists. The question of the specific +distinction of the African and American Manatees will be treated of +further on, but it will be chiefly to the latter and better known form +that the following description applies. + +[Illustration: FIG. 71.—American Manatee (_Manatus americanus_), from +life. _Proc. Zool. Soc._ 1881, p. 457.] + +The size of the Manatee has been much exaggerated, but there is no +trustworthy evidence of its attaining a greater length than 8 feet. Its +general external form may be seen in Fig. 71, taken from a living example +in the Brighton Aquarium. The body is somewhat fish-like, but depressed +and ending posteriorly in a broad, flat, shovel-like, horizontal tail, +with rounded edges. The head is of moderate size, oblong, with a blunt, +truncated muzzle, and divided from the body by a very slight constriction +or neck. The fore limbs are flattened oval paddles, placed rather low +on the sides of the body, and showing externally no signs of division +into fingers, but with a tolerably free motion at the shoulder, elbow, +and wrist joints, and with three diminutive flat nails near their +extremities. No traces of hind limbs are discernible either externally +or internally; and there is no dorsal fin. The mouth is very peculiar, +the tumid upper lip being cleft in the middle line into two lobes, each +of which is separately movable, as will be described in speaking of its +manner of feeding. The nostrils are two semilunar valve-like slits, at +the apex of the muzzle. The eyes are very minute, placed at the sides +of the head, and with a nearly circular aperture with wrinkled margins. +The external ear is a minute orifice situated behind the eye, without +any trace of pinna. The skin generally is of a dark grayish colour, not +smooth and glistening, like that of the Cetacea, but finely wrinkled. At +a little distance it appears naked, but a close inspection, at all events +in young animals, shows a scanty covering of very delicate hairs, and +both upper and under lips are well supplied with short stiff bristles. + +[Illustration: FIG. 72.—Skull of African Manatee (_Manatus +senegalensis_). ⅕ natural size. From Mus. Roy. Coll. Surgeons.] + +The general form of the skull is seen in Fig. 72. The cerebral cavity +is rather small as compared with the size of the animal, and of oblong +form; its roof is formed of the parietal bones as in ordinary mammals. +The squamosal has an extremely large and massive zygomatic process, which +joins the largely developed jugal bone in front. The orbit is small, +but prominent and nearly surrounded by bone. The anterior nares taken +together form a lozenge-shaped aperture, which looks upwards and extends +backwards considerably behind the orbits. Their sides are formed by the +ascending processes of the premaxillæ below, and by the supraorbital +processes of the frontals above, no traces of nasals being found in most +skulls, though these bones are occasionally present in a most rudimentary +condition, attached to the edges of the frontals, far away from the +middle line, in a position quite unique among the Mammalia. In front of +the narial aperture the face is prolonged into a narrow rostrum, formed +by the premaxillæ, supported below and at the sides by the maxillæ. +The under surface of this is very rugose, and in life covered by a +horny plate. The rami of the mandible are firmly united together at +the symphysis, which is compressed laterally, slightly deflected, and +has a rugose upper surface; to this another horny plate is attached, +which, with that of the upper jaw, functionally supplies the place of +teeth in the anterior part of the mouth. In the young state there are +rudimentary teeth concealed beneath these horny plates, which never +penetrate through them, and must therefore be quite functionless, and +altogether disappear before the animal is full-grown. There is besides +on each side of the hinder part of both upper and lower jaws, a parallel +row of molar teeth, similar in characters from the beginning to the end +of the series, with square enamelled crowns raised into tuberculated +transverse ridges; something like those of the Tapir and Kangaroo. The +upper teeth have two ridges and three roots; the lower teeth have an +additional posterior small ridge or talon, and but two roots. These teeth +succeed each other from before backwards, as in the Proboscidea, those +at the front of the mouth being worn out and shed before those at the +back are fully developed. There are altogether about eleven on either +side of each jaw, but rarely more than six are present at one time. The +brain is remarkably simple in structure, its hemispheres exhibiting none +of the richness of convolution so characteristic of the Cetacea. The +mammary glands of the female are situated just behind and to the inner +side of the origin of the pectoral limb. The red corpuscles of the blood +are among the largest of those of any members of the class, averaging in +diameter, according to Gulliver, ¹⁄₂₄₀₀ of an inch. + +Manatees pass the whole of their life in the water, inhabiting bays, +lagoons, estuaries, and large rivers; but the open sea, so congenial +to the Cetacea, is quite unsuited to their peculiar mode of life. As a +general rule they prefer shallow water, in which, when not feeding, they +lie near the bottom, supporting themselves on the extremity of the tail, +or slowly moving about by the assistance of the fore limbs, the tips of +which are just allowed to touch the ground, and only raising the top of +the head above the surface for the purpose of breathing at intervals of +two or three minutes. In deeper water they often float, with the body +much arched, the rounded back close to the surface, and the head, limbs, +and tail hanging downwards. The air in the lungs obviously assists them +to maintain this position, acting in the same manner as that in the +air-sac of fishes. Their food consists exclusively of aquatic plants, +on which they browse beneath the water. They are extremely slow and +inactive in their movements, and perfectly harmless and inoffensive. +Frequent attempts have been made to keep specimens alive in captivity, +and sometimes with considerable success, one having lived in the Brighton +Aquarium for upwards of sixteen months. It was fed chiefly on lettuce +and endive, but would also eat leaves of the dandelion, sow-thistle, +cabbage, turnip, and carrot. From this and other captive specimens some +interesting observations upon the mode of life of the animal have been +made. One of these is the free use it makes of its fore limbs. From the +shoulder-joint, they can be moved in all directions, and the elbow and +wrist permit of free extension and flexion. In feeding these creatures +push the food towards their mouths by means of one of the hands, or both +used simultaneously, and any one who has seen these members thus employed +can readily believe the stories of their carrying their young about +under their arms. Still more interesting and quite unique among mammals +is the action of the peculiar lateral pads formed by the divided upper +lip, thus described by the late Professor Garrod: “These pads have the +power of transversely approaching towards and receding from one another +simultaneously (see Fig. 73, A and B). When the animal is on the point of +seizing (say) a leaf of lettuce, the pads are diverged transversely in +such a way as to make a median gap of considerable breadth. Directly the +leaf is within grasp the lip-pads are approximated, the leaf is firmly +seized between their contiguous bristly surfaces, and then drawn inwards +by a backward movement of the lower margin of the lip as a whole.” The +animal is thus enabled by the unaided means of the upper lip to introduce +food placed before it without the assistance of the comparatively +insignificant lower lip, the action greatly recalling to the observer +that of the mouth of the silkworm and other caterpillars, in which the +mandibles diverge and converge laterally during mastication. When out +of water the Manatee is an extremely helpless animal; and, although +statements are frequently met with in books of its voluntarily leaving +the water for the purpose of basking or feeding on shore, all trustworthy +observations of those acquainted with it, either in a state of nature or +in captivity, indicate that it has not the power of doing so. None of the +specimens in confinement have been observed to emit any sound. + +[Illustration: FIG. 73.—Front view of head of American Manatee, showing +the eyes, nostrils, and mouth. A, With the lobes of the upper lip +divaricated; B, with the lip contracted. From Murie, _Trans. Zool. Soc._ +vol. xi.] + +Manatees, though much less numerous than formerly, are still occasionally +found in creeks, lagoons, and estuaries in some of the West India +Islands, and at various spots on the Atlantic coast of America from +Florida as far south as about 20° S. lat., and in the great rivers of +Brazil, almost as high as their sources. They are also met with in +similar situations on the opposite African coast, from about 16° N. to +10° S. lat., and as far into the interior as Lake Tchad. Their range may +even extend, if native reports obtained by Schweinfurth are correctly +interpreted, to the river Keebaly, 27° E. long. + +A considerable number of specific names have been applied to the existing +Manatees, but according to the researches of Dr. Hartlaub[117] they +may be reduced to three species, distinguished from one another, among +other features, by the characters of the skull, and more especially the +relations of the nasals to the adjacent bones. Of these the American +Manatee may be known as _M. americanus_, although it has been described +under the names of _M. latirostris_, and _M. australis_. The African +Manatee (_M. senegalensis_) differs from the American species in the +following cranial characters: the anterior part of the rostrum is +shorter, shallower, and altogether smaller; the orbit is smaller; the +zygomatic process is more deep and massive; the jugal bone is deeper +from above downwards; the upper margin of the anterior nares is narrower +and with a smooth and rounded, instead of a thin and serrated, edge; the +upper surface of the frontal is flat, instead of concave; the foramen +magnum and occipital condyles are narrower from side to side, and the +symphysis of the mandible is smaller and shallower. + +Finally, _M. inunguis_ is a fluviatile species confined to the Amazon and +Orinoco, which has been but recently fully brought under the notice of +zoologists. + + +_Family_ HALICORIDÆ. + +_Halicore._[118]—In the upper jaw a pair of large, nearly straight, +tusk-like incisors, directed downwards and forwards, partially coated +with enamel. In the male they have persistent pulps, and bevelled cutting +edges, which project a short distance from the mouth, but in the female, +though they remain through life in the alveolar cavity, they are not +exserted, and, the pulp-cavity being filled with osteodentine, they soon +cease to grow (as in the female Narwhal). In the young there is also a +second small deciduous incisor on each side above. At this age there are +also beneath the horny plate which covers the anterior portion of the +mandible four pairs of slender conical teeth lodged in wide alveolar +depressions; these become absorbed before the animal reaches maturity. +The molars are usually ⁵⁄₅, sometimes ⁶⁄₆, altogether, but not all in +place at once, as the first falls before the last rises above the gum; +they are more or less nearly cylindrical in section (except the last, +which is compressed and grooved laterally), without distinction into +crown and root, increasing in size from before backwards, with persistent +pulps and no enamel. The summits of the crowns are tuberculated before +wearing, afterwards flattened or slightly concave. Skull with rostrum +formed by the union of the premaxillæ in front of the narial aperture, +longer than the aperture itself, bending downwards at a right angle with +the basicranial axis, and enclosing the sockets of the large incisor +tusks. Anterior part of the lower jaw bent down in a corresponding +manner. Vertebræ: C 7, D 18-19, L and C 30. Tail broadly notched in the +middle line, and with two pointed lateral lobes. No nails on the fore +limbs. Cæcum single. + +The Dugongs are more distinctly marine in their habits than the Manatees, +feeding chiefly on sea-water algæ. They inhabit the shallow bays and +creeks of the Red Sea, east coast of Africa, Ceylon, islands of the Bay +of Bengal and the Indo-Malayan Archipelago (including the Philippines), +and the north coast of Australia, ranging from Barrow Reefs on the west +to Moreton Bay on the east. Although the distinctive characters are not +very obvious, they have been divided into three species, according to the +localities which they respectively inhabit:—_H. tabernaculi_ from the Red +Sea, _H. dugong_ from the Indian seas, and _H. australis_ from Australia. +The last-named has lately been the object of a regular “fishery,” chiefly +on account of its oil, which is peculiarly clear, limpid, and free from +disagreeable smell, and is said to have the same medicinal properties as +cod-liver oil. Although often stated in books to attain the length of 20 +feet when adult, there does not appear to be any evidence from actual +specimens in museums that Dugongs ever reach half that size, 8 feet being +the common length of adult animals. + +The placentation of this genus has been recently described by Sir W. +Turner, who first indicated its zonary form. + + +_Family_ RHYTINIDÆ. + +_Rhytina._[119]—No teeth, their place being supplied functionally by the +dense, strongly-ridged, horny oral plates. Premaxillary rostrum about as +long as the anterior narial aperture, and moderately deflected. Vertebræ: +C 7, D 19, L and C 34-37. Head very small in proportion to the body. Tail +with two lateral pointed lobes. Pectoral limbs small and truncated. Skin +naked and covered with a very thick, hard, rugged, bark-like epidermis. +Stomach without cæcal appendages to the pyloric cavity. Cæcum simple. + +Only one species of this genus is known, _R. stelleri_, the Northern +Sea-cow, by far the largest animal of the order, attaining the length of +20 to 25 feet. It was formerly an inhabitant of the shores of two small +islands in the North Pacific, Behring and the adjacent Copper Island, +on the former of which it was discovered by the ill-fated navigator +whose name the island bears, when, with his accomplished companion, the +German naturalist Steller, he was wrecked upon it in 1741. Twenty-seven +years afterwards (1768), as is commonly supposed, the last of the race +was killed,[120] and its very existence would have been unknown to +science but for the interesting account of its anatomy and habits left by +Steller, and the few more or less imperfect skeletons which have recently +rewarded the researches carried on in the frozen soil of the islands +around which it dwelt. There is no evidence at present of its having +inhabited any other coasts than those of the islands just named, although +it can hardly be supposed that its range was always so restricted. When +first discovered it was extremely numerous in the shallow bays round +Behring Island, finding abundant nutriment in the large laminariæ growing +in the sea. Its extirpation is entirely due to the Russian hunters and +traders who followed upon the track of the explorers, and, upon Steller’s +suggestion, lived upon the flesh of the great Sea-cows. Its restricted +distribution, large size, inactive habits, fearlessness of man, and even +its affectionate disposition towards its own kind when wounded or in +distress, all contributed to accelerate its final extinction. + +According to Steller’s account, the Rhytina had a skin of a dark brown +colour, sometimes spotted or streaked with white. The fore limb was +covered with short brush-like hairs. + + +_Extinct_ SIRENIANS. + +_Halitherium._[121]—The Miocene and early Pliocene seas of Europe +abounded in Sirenians, to which the generic name of _Halitherium_ was +given by Kaup, but which have also received other names. They had large +tusk-like incisors in the upper jaw, as in the existing Dugongs, though +not so greatly developed. Their molar teeth were ⁵⁄₅ or ⁶⁄₆, anteriorly +simple and single-rooted, posteriorly those above with three and those +below with two roots, and with enamelled and tuberculated or ridged +crowns, in all which respects they more resemble those of the Manatee +than of the Dugong. The anterior molars were deciduous; and there is +evidence of the presence of milk-teeth. Germs of inferior incisors were +also present. Some species at least had nasal bones, short, broad, but +normal in position, whereas in all the existing genera these bones +are quite rudimentary. Another and still more important evidence of +conformity to the general mammalian type is the better development of +the pelvic bone, and the presence of a small styliform femur articulated +to the acetabulum, although no traces of any other part of the limb +have been discovered. These ancient Sirenians, which may be regarded +as representing a distinct family—_Halitheriidæ_—were thus, in dental, +cranial, and other osteological characters, less specialised than are +either of the existing species, and if the intermediate links could be +discovered might well be looked upon as the ancestral forms from which +the latter have been derived, but at present the transitional conditions +have not been detected. So far as is yet known, when changes in the +physical conditions of the European seas rendered them unfitted to be the +habitation of Sirenians, the _Halitherium_ type still prevailed. If the +existing Dugongs and Manatees are descended from it, their evolution must +have taken place during the Pliocene and Pleistocene epochs, the one in +seas to the east, the other to the west of the African continent, which +has long formed a barrier to their intercommunication. _Halitherium_ +remains have been found in many parts of Germany, especially near +Darmstadt, also in France, Italy, Belgium, Malta, etc. Until a few years +ago none were known from England, probably owing to the absence of beds +of an age corresponding to those in which they are found on the European +continent; but a skull and several teeth have been detected among the +rolled debris of which the Red Crag of Suffolk is partially composed. The +species are not yet satisfactorily characterised. Some of them appear +to have attained a larger size than the existing Manatee or Dugong. One +of these, from the Pliocene of Italy and France, having but ⁵⁄₅ molar +teeth, has been separated generically under the name of _Felsinotherium_ +by Capellini, by whom it has been fully described; but the difference in +the number of the teeth does not afford sufficient grounds for separation +from _Halitherium_. _Miosiren_ of the Belgian Miocene, differs in that +the last upper molar is the smallest, in place of the largest of the +whole series of teeth. + +[Illustration: FIG. 74.—The penultimate and last right lower molars of +_Halitherium fossile_; from the Miocene of the Continent. (After De +Blainville.)] + +_Other forms._—Remains from the Pliocene of France described as +_Prohalicore_ are regarded as indicating a Sirenian closely allied to +_Halicore_; while a molar from the Tertiary of California has been made +the type of _Desmotylus_, which is likewise referred to the _Halicoridæ_. +_Dioplotherium_, from the Phosphorites of South Carolina, has been +considered to connect _Halicore_ with _Halitherium_, but even its ordinal +position is uncertain. + +A portion of a skull found in the Pliocene of Belgium has been described +as _Crassitherium_ by Van Beneden; and some compressed teeth, somewhat +similar to but larger than those of the Dugong, discovered in the Miocene +of the department of Lot-et-Garonne, France, gave origin to the genus +_Rytiodus_ of E. Lartet. Of this genus, which may be identical with +_Trachytherium_ of the French Miocene, better preserved remains have +subsequently been described by Delfortrie. These show that the rostrum +is more elongated than in _Halitherium_, but the skull is otherwise very +similar, as are the molar teeth. The incisors are very large, exserted, +strongly compressed, almost sabre-like, rounded on the upper or anterior +surface, sharp below, concave on the external and convex on the inner +side, and transversely striated. + +_Pachyacanthus_ from the Miocene of the Vienna basin is also, according +to Van Beneden, another form of Sirenian, of which, however, the skull +is not known. In various Miocene marine formations of the United States +of America other remains of Sirenians have been found, but mostly in +such a fragmentary condition that they afford at present little evidence +of the early history of the group in that country. A more satisfactory +discovery is that of a nearly complete skull and some bones from a +Tertiary limestone formation in Jamaica. It is of smaller size than +the Manatee, and, so far as the teeth are concerned, of a still more +generalised character than _Halitherium_, the dentition being apparently +_i_ ³⁄₃, _c_ ¹⁄₁, _p_ + _m_ (?⁸⁄?₈) = 48. The incisors are small, not +developed into tusks; the canines (wanting in all existing Sirenians) +are rather larger than the incisors, judging by the sockets; and the +molars are bilophodont, and covered with enamel. It has been described +by Sir R. Owen under the name of _Prorastomus sirenoides_. Some writers +regard this genus as the type of a distinct family—the _Prorastomatidæ_. +Unfortunately we have no knowledge of the geological antiquity of +the formation in which it was embedded. Lastly must be mentioned the +_Eotherium egyptiacum_, Owen, founded on the cast of a brain, with +a small quantity of surrounding bone, discovered in the nummulitic +limestone of Eocene age in the Mokattam Hills, near Cairo. The brain is +narrower than in _Manatus_, and resembles that of _Halitherium_. This is +of interest as the most ancient known evidence of any Sirenian whose age +has been geologically determined. Teeth from the same deposits referred +to _Manatus_ not improbably belong really to _Eotherium_. + +The few facts as yet collected relating to the former history of the +Sirenia leave us as much in the dark as to the origin and affinities of +this peculiar group of animals as we were when we only knew the living +members. They lend no countenance to their association with the Cetacea, +and on the other hand their supposed affinity with the Ungulata, so much +favoured by modern zoologists, receives no very material support from +them. + + _Bibliography of Sirenia._—J. F. Brandt, _Symbolæ + Sirenologicæ_, St. Petersburg, 3 fasciculi, 1846-61-68—an + exhaustive account of the anatomy, affinities, and literature + of the group, with copious illustrations of the osteology of + _Rhytina_. _Anatomy of Dugong_:—Everard Home, _Phil. Trans._ + 1820, p. 315; Owen, _Proc. Zool. Soc._ 1838, p. 29. _Placenta + of do._:—W. Turner, _Trans. Roy. Soc. Edin._ vol. xxxv. + (1889). _Manatee_:—W. Vrolik, _Bijdragen tot de Dierkunde_, + 1851; J. Murie, “On the Form and Structure of the Manatee,” + _Trans. Zool. Soc. Lond._ vol. viii. p. 127, 1872, and “Further + Observations on the Manatee,” _Ibid._ vol. xi. p. 19, 1880; + A. H. Garrod, “Notes on the Manatee recently living in the + Zoological Society’s Gardens,” _Ibid._ vol. x. p. 137, 1875; + H. C. Chapman, “Observations on the Structure of the Manatee,” + _Proc. Acad. Nat. Sciences of Philadelphia_, 1875, p. 452; A. + Crane, “Notes on the Habits of the Manatees in Captivity in + the Brighton Aquarium,” _Proc. Zool. Soc. Lond._ 1881, p. 456. + _Extinct Sirenia_:—Gervais, _Journal de Zoologie_, tom. i. p. + 332, 1872. R. Lydekker, _Catalogue of Fossil Mammalia in the + British Museum_, pt. v. + + +_Order_ CETACEA. + +This is perhaps the most distinctly circumscribed and natural of all the +larger groups into which the class is divided. + +The external form is fish-like, the body being fusiform, passing +anteriorly into the head without any distinct constriction or neck, and +posteriorly tapering off gradually towards the extremity of the tail, +which is provided with a pair of lateral, pointed expansions of skin +supported by dense fibrous tissue, called “flukes,” forming together a +horizontally-placed triangular propelling organ, notched in the middle +line behind. + +The head is generally large, in some species attaining to even more +than one-third of the entire length of the animal, and the aperture of +the mouth is always wide, and bounded by stiff immobile lips. The fore +limbs are reduced to the condition of flattened ovoid paddles, encased +in a continuous integument, showing no external sign of division into +arm, fore arm, and manus, or of separate digits, and without any trace +of nails. There are no traces of hind limbs visible externally. The +general surface of the skin is smooth and glistening, and devoid of +hair, although in many species there are a few fine bristles in the +neighbourhood of the mouth, which may either persist through life, or +be present only in the young state. Immediately beneath the skin, and +intimately connected with it, is a thick layer of fat, held together +by a dense mesh of areolar tissue, constituting the “blubber,” which +serves the purpose of the hairy covering of other mammals in retaining +the heat of the body. In nearly all species a compressed median dorsal +tegumentary fin is present. The eye is small, and is not provided with a +nictitating membrane or true lachrymal apparatus. The external auditory +meatus is a very minute aperture in the skin situated at a short distance +behind the eye, and there is no vestige of a pinna. The nostrils open +either separately or by a single crescentic valvular aperture, not at the +extremity of the snout, but near the vertex of the head. + +The bones generally are spongy in texture, the cavities being filled with +oil. In the vertebral column the cervical region is remarkably short and +immobile, and the vertebræ, originally always seven in number, are in +many species more or less fused together into a solid mass. The odontoid +process of the axis, when that bone is free, is usually very obtuse, or +even obsolete. None of the vertebræ are united together to form a sacrum. +The lumbar and caudal vertebræ are numerous and large, and, as their +arches are not connected by any articular processes (zygapophyses), they +are capable of a very free motion in all directions. The epiphyses at +the ends of the vertebral bodies are very distinct flattened disks, not +uniting until after the animal has attained its full dimensions.[122] +There are largely developed chevron bones, the presence of which +indicates the distinction between the caudal and lumbar vertebræ. + +The skull (Fig. 75) is modified in a very peculiar manner. The brain-case +is short, broad, and high, in fact almost spherical. The supraoccipital +bone rises upwards and forwards from the foramen magnum, to meet the +frontals at the vertex, thus completely excluding the parietals from the +upper region of the cranium. The frontals are expanded laterally to form +the roof of the orbits. The anterior narial aperture opens upwards, and +has in front of it a more or less horizontally prolonged rostrum, formed +of the maxillæ, premaxillæ, vomer, and mesethmoid cartilage, extending +forwards to form the upper jaw or roof of the mouth. + +There are no clavicles. The humerus is freely movable on the scapula +at the shoulder-joint, but beyond this the articulations of the limb +are imperfect, the flattened ends of the bones coming in contact with +each other, with fibrous tissue interposed, allowing of scarcely any +motion. The radius and ulna are distinct, about equally developed, +and much flattened, as are also all the bones of the manus. There are +four, or more commonly five digits, and the number of the phalanges +of the second and third digits always exceeds the normal number in +mammals, sometimes very considerably (hyperphalangism); they present the +exceptional character of having epiphyses at both ends.[123] The pelvis +is represented by a pair of small styliform bones placed longitudinally, +suspended below and at some distance from the vertebral column at the +commencement of the caudal region. These appear to represent the ischia, +as the crura of the corpora cavernosa are attached to them. In some +species, to the outer surface of these are fixed other small bones or +cartilages, the rudiments of the hind limb. + +[Illustration: FIG. 75.—A section of the skull of a young Dolphin +(_Globicephalus melas_) × ⅕. _PMx_, Premaxilla; _Mx_, maxilla; _ME_, +ossified portion of the mesethmoid; _an_, anterior nares; _Na_, nasal; +_IP_, interparietal; _Fr_, frontal; _Pa_, parietal; _SO_, supraoccipital; +_ExO_, exoccipital; _BO_, basioccipital; _Sq_, squamosal; _Per_, +periotic; _AS_, alisphenoid; _PS_, presphenoid; _Pt_, pterygoid; _pn_, +posterior nares; _Pl_, palatine; _Vo_, vomer; _s_, symphysis of mandible; +_id_, inferior dental canal; _cp_, coronoid process of mandible; _cd_, +condyle; a, angle; sh, stylohyal; _bh_, basihyal; _th_, thyrohyal. (From +Flower’s _Osteology of Mammalia_.)] + +Teeth are generally present, but exceedingly variable in number. In +the existing species they are of simple, uniform character, all having +conical or compressed crowns and single roots, and are never preceded +by milk-teeth. They are therefore homodont and monophyodont. In one +group, the Mystacocetes, the teeth are absent (except, in the fœtal +condition), and the palate is provided with numerous transversely placed +horny laminæ or “baleen.” The salivary glands are rudimentary or absent. +The stomach is multilocular, its structure being fully noticed under +the genus _Phocæna_. The intestinal canal is simple, and only in some +species provided with a small cæcum. The liver is very little fissured, +and there is no gall-bladder. The vascular system is greatly complicated +by arterial and venous plexuses, or _retia mirabilia_. The larynx is of +peculiar shape, the arytenoid cartilages and the epiglottis being much +elongated, and together forming a tubular prolongation, which projects +into the posterior nares, and when embraced by the soft palate produces a +continuous passage between the nostrils and the trachea, as in Ungulates, +but in a more perfect manner. The brain is large relatively to the size +of the animal, very round in form, and with its surface divided by sulci +into very numerous and complex convolutions. The kidneys are deeply +lobulated. The testes are abdominal. There are no vesiculæ seminales, +nor os penis. The uterus is bicornuate, and the placenta non-deciduate +and diffuse. The mammæ are two in number, and the nipples placed in +depressions on each side of the vulva. The principal ducts of the gland +are dilated during lactation into large reservoirs, into which the milk +collects, and from which it is injected by the action of a compressor +muscle into the mouth of the young animal, by which means the process of +sucking under water is greatly facilitated and expedited. + +The animals of the order Cetacea abound in all known seas, and some +species are inhabitants of the larger rivers of South America and Asia. +Their organisation necessitates passing their life entirely in the +water, as on land they are absolutely helpless. They have, however, to +rise very frequently to the surface for the purpose of respiration; and, +in relation to the constant upward and downward movement in the water +thus necessitated, their principal instrument of motion, the tail, is +expanded horizontally, quite unlike that of a fish, whose movements +are mainly in straight-forward or lateral directions. The position of +the respiratory orifice or nostril on the highest part of the head is +very important for this mode of life, since it is the only part of the +body of which the exposure above the surface is absolutely necessary. +Of the numerous erroneous ideas connected with natural history, few are +so wide spread and still so firmly believed, notwithstanding repeated +expositions of its falsity, as that the Cetacea spout out through their +blowholes water taken in at the mouth. The fact is, the “spouting,” or +more properly “blowing,” of the Whale is nothing more than the ordinary +act of expiration, which, taking place at longer intervals than in land +animals, is performed with a greater amount of emphasis. The moment the +animal rises to the surface it forcibly expels from its lungs the air +taken in at the last inspiration, which of course is highly charged with +watery vapour in consequence of the natural respiratory changes. This, +rapidly condensing in the cold atmosphere in which the phenomenon is +generally observed, forms a column of steam or spray, which has been +erroneously taken for water. It also often happens, especially when the +surface of the ocean is agitated into waves, that the animal commences +its expiratory puff before the orifice has quite cleared the top of +the water, some of which may thus be driven upwards with the blast, +tending to complete the illusion. In hunting Whales the harpoon often +pierces the lungs or air passages of the unfortunate victim, and then +fountains of blood may be forced high in the air through the blowholes, +as commonly depicted in scenes of Arctic adventure; but this is nothing +more (allowance being made for the Whale’s peculiar mode of breathing) +than what always follows severe wounds of the respiratory organs of other +mammals. + +All the Cetacea are predaceous, subsisting on living animal food of +some kind. One genus alone (_Orca_) eats other warm-blooded animals, as +Seals, and even members of its own order, both large and small. Some feed +on fish, others on small floating crustaceans, pteropods, and medusæ, +while the principal staple of the food of many is constituted by the +various species of cephalopods, _Loligo_ and other _Teuthidæ_, which must +abound in certain seas in vast numbers, as they form almost the entire +support of some of the largest members of the order. In size the Cetacea +vary much, some of the smaller Dolphins scarcely exceeding 4 feet in +length, while others are the most colossal of all animals. It is true +that most statements of their bulk found in general and even zoological +literature are greatly exaggerated, but even when reduced to their actual +dimensions (which will be stated under the respective genera) some of +the existing Whales exceed in size any animal living either at present +or in former times of which we have any certain evidence. With some +exceptions, the Cetacea generally are timid inoffensive animals, active +in their movements, and very affectionate in their disposition towards +one another, especially the mother towards the young, of which there is +usually but one, or at most two at a time. They are generally gregarious, +swimming in herds or “schools” (so termed by the whalers) sometimes +amounting to many thousands in number; though some species have hitherto +only been met with either singly or in pairs. + +Although by their mode of life so far removed from close observation +that it is impossible to become as familiar with them in their natural +condition as with many other animals, Whales are in many respects the +most interesting and wonderful of all creatures; and there is much in +their structure and habits well worthy of study, much that is difficult +to understand, and much that leads to great generalisations and throws +light upon far-reaching philosophical speculations. One of the first +lessons which a study of these animals affords is that, in the endeavour +to discover what a creature really is, from what others it is descended, +and to what it is related, the general outward appearance affords little +clue, and we must go deep below the surface to find out the essential +characteristics of its nature. There was once, and may be still in many +places, a common idea that a Whale is a fish. To realise the fallacy of +this notion we have only to consider what a fish really is, what under +all the diversities of form, size, and colour known among fishes there is +common to them all, and we see that in everything which characterises a +true fish and separates it from other classes, as reptiles, birds, and +mammals, the Whale resembles the last-named and differs from the fish. +It is as essentially a mammal as a Cow or a Horse, and simply resembles +a fish externally because it is adapted to inhabit the same element; +but it is no more on that account a fish than is a bat, because adapted +to pass a great part of its existence on the wing in the air, nearly +related to a bird. The whole structure of a whale is a most instructive +instance of a type of organisation which is common to and characteristic +of the class Mammalia, but specially modified or adapted to a peculiar +mode of life. We see in every part the result of two great principles +acting and reacting upon each other—on the one hand, adherence to type, +or rather to fundamental inherited structural conditions, and, on the +other, adaptation to the peculiar circumstances under which it lives, and +to which in all probability it has become gradually more and more fitted. +The external fish-like form is perfectly suited for swimming through +the water; the tail, however, is not placed vertically as in fishes, +but horizontally, a position which accords better with the constant +necessity for rising to the surface for the purpose of breathing. The +hairy covering characteristic of all mammals, which if present might +interfere with rapidity of movement through the water, is reduced to the +merest rudiments—a few short bristles about the chin or upper lip—which +are often only present in very young animals; and the function of keeping +the body warm is supplied by the “blubber.” The forelimbs, though +functionally reduced to mere paddles, with no power of motion except at +the shoulder-joint, have beneath their smooth and continuous external +covering all the bones, joints, and even most of the muscles, nerves, and +arteries of the human arm and hand; and the rudiments of hind legs found +buried deep in the interior of the animal apparently subserve no useful +purpose, but point an instructive lesson to those who are able to read it. + +As before said, the Cetacea form a perfectly well-defined group, sharply +separated from all other mammals, and with no outlying or doubtful +forms at present known. Among the existing members of the order, there +are two very distinct types, the Toothed Whales or Odontoceti and the +Baleen Whales or Mystacoceti, which present as many marked distinguishing +structural characters as are found between many other divisions of the +Mammalia which are reckoned as orders. The extinct _Zeuglodon_, so far +as its characters are known, does not fall into either of these groups, +but is in some respects an annectant form, and therefore must be placed, +provisionally at least, in a third group by itself. + +The Mystacocetes appear at first sight to be the most specialised and +aberrant of the existing Cetacea, as indicated by the absence of teeth, +the presence of baleen, and the form and size of the mouth; but, as we +see in other groups, dental characters, and all such as relate to the +prehension of food generally, are essentially adaptive and consequently +plastic or prone to variation, and hence cannot well be relied upon +as tests of affinity. In another character, also adaptive, the laxity +of the connection of the ribs with the vertebral column and with the +sternum, and the reduction of that bone in size, allowing great freedom +of expansion of the thoracic cavity for prolonged immersion beneath +the water, the Mystacocetes have passed beyond the Odontocetes in +specialisation. On the other hand, the greater symmetry of the skull, the +more anterior position of the external nostrils and their double external +orifice, the form of the nasal bones, the presence of a distinctly +developed olfactory organ, the mode of attachment of the periotic bone to +the cranium, the presence of a cæcum and the regular arrangement of the +alimentary canal, the more normal characters of the manus and the better +development of the muscles attached to it, and the presence, in many +species at least, of parts representing not only the bones but also the +ligaments and muscles of a hind limb,[124] all show less deviation from +the ordinary mammalian type than is presented by the Odontocetes. Taking +all these characters into consideration, it does not appear reasonable to +suppose that either type has been derived from the other, at all events +in the form in which we see it now, but rather that they are parallel +groups, both modified in different fashions from common ancestors. + +Among the Mystacocetes, in the especially distinguishing characters of +the division, the Rorquals are less specialised than the Right Whales, +which in the greater size of the head, the length and compression of the +rostrum, the development of the baleen, and shortness of the cervical +region, are exaggerated forms of the type, and yet they retain more fully +some primitive characters, as the better development of the hind limb, +the pentadactylous manus, and the absence of a dorsal fin. Both types +are found distinct in a fossil state at least as far back as the early +Pliocene age, but generally represented by smaller species than those +now existing. Some of the Pliocene Rorquals (_Cetotherium_) were, in +the elongated flattened form of the nasal bones, the greater distance +between the occipital and frontal bone at the top of the head, and the +greater length of the cervical vertebræ, more generalised than those +now existing. In the shape of the mandible also, Van Beneden, to whose +researches we are much indebted for a knowledge of these forms, discerns +some approximation to the Odontocetes. + +Among the last-named group there are several distinct types, of which +that represented by _Platanista_, although in some respects singularly +modified, has been considered to present on the whole approximations +towards the more normal and general type of mammalian structure. It is +therefore interesting to find an apparently allied form well represented +among the earliest fossil remains of Cetaceans in Europe. Almost all the +other members of the suborder range themselves under the two principal +heads of Ziphioids (or Physeteroids) and Delphinoids. The former is an +ancient and once abounding type, of which the Sperm Whale (_Physeter_) +is a highly specialised form. Among the latter, _Globicephalus_ is a +modified form as regards the structure of its anterior extremity, and +_Monodon_ as regards its dentition, while _Delphinus_, with the various +allied genera, may be regarded as the dominating type of Cetaceans at +the present day, abundant in slightly differentiated species and also in +individuals. They are in this respect to the rest of the order much as +the hollow-horned Ruminants are to the other Ungulates. + +The earliest Cetaceans of whose organisation we have anything like +complete evidence are the Zeuglodonts of the Eocene period,[125] +which approach in the structure of the skull and teeth to a much more +generalised mammalian type than either of the existing suborders. The +smallness of the cerebral cavity compared with the jaws and the rest +of the skull they share with the primitive forms of many other types. +The forward position of the narial aperture and the length and flatness +of the nasal bones, which distinguish them from all existing forms, we +must also suppose to be a character at one time common to all Cetaceans, +though now retained (but to a less degree) only by the Mystacocetes. +Even _Squalodon_, which in its heterodont dentition so much resembles +_Zeuglodon_ as to have been placed by some zoologists in the same genus, +entirely differs from it, and conforms with the ordinary Dolphins in its +essential cranial characters. + +The origin of the Cetacea is at present involved in much obscurity. +They present no signs of closer affinity to any of the lower classes of +vertebrates than do many other members of their own class. Indeed in all +that essentially distinguishes a mammal from the oviparous vertebrates, +whether in the osseous, nervous, reproductive, or any other system, +they are as truly mammalian as any other group. Any supposed marks +of inferiority, as absence of limb structure, of hairy covering, of +lachrymal apparatus, etc., are obviously modifications (or degradations, +as they may be termed) in adaptation to their special mode of life. The +characters of the teeth of _Zeuglodon_ and other extinct forms, and +also of the fœtal Mystacocetes, clearly indicate that they have been +derived from mammals in which the heterodont type of dentition was fully +established. The steps by which a land mammal may have been modified +into a purely aquatic one are indicated by the stages which still +survive among the Carnivora in the _Otariidæ_ and in the true Seals. A +further change in the same direction would produce an animal somewhat +resembling a Dolphin; and it has been thought that this may have been +the route by which the Cetacean form has been developed. There are, +however, great difficulties in the way of this view. Thus if the hind +limbs had ever been developed into the very efficient aquatic propelling +organs they present in the Seals, it is not easy to imagine how they +could have become completely atrophied and their function transferred to +the tail. So that from this point of view it is more likely that Whales +were derived from animals with long tails, which were used in swimming, +eventually with such effect that the hind limbs became no longer +necessary. The powerful tail, with its lateral cutaneous flanges, of an +American species of Otter (_Lutra brasiliensis_) may give an idea of this +member in the primitive Cetaceans. But the structure of the Cetacea is, +in so many essential characters, so unlike that of the Carnivora that +the probabilities are against these orders being nearly related. Even in +the skull of the Zeuglodon, which has been cited as presenting a great +resemblance to that of a Seal, quite as many likenesses may be traced to +one of the primitive Pig-like Ungulates (except in the purely adaptive +character of the form of the teeth), while the elongated larynx,[126] +complex stomach, simple liver, reproductive organs both male and female, +and fœtal membranes of the existing Cetacea are far more like those +of that group than of the Carnivora. Indeed it appears probable that +the old popular idea which affixed the name of “Sea-Hog”[127] to the +Porpoise contains a larger element of truth than the speculations of many +accomplished zoologists of modern times. The fact that _Platanista_, +which, as mentioned above, appears to retain more of the primitive +characteristics of the group than any other existing form, and also the +somewhat related _Inia_ from South America, are both at the present day +exclusively fluviatile, may point to the freshwater origin of the whole +group, in which case their otherwise rather inexplicable absence from the +seas of the Cretaceous period would be accounted for. + +On the other hand, it should be observed that the teeth of the +Zeuglodonts approximate more to a carnivorous than to an ungulate type. +It is scarcely necessary to allude to the hypothesis started by some +Continental writers to the effect that the Whales are the most primitive +type of mammals with which we are acquainted, and that they are the +descendants of the Mesozoic reptilian order Ichthyopterygia, from which +their hyperphalangism is a direct inheritance. The Ichthyopterygia have +been shown, on very strong evidence, to have been derived from land +reptiles, and to have gradually acquired their hyperphalangism as an +adaptive character suitable to their peculiar mode of life, and there can +be but little doubt that a similar adaptation has taken place in the case +of the Whales. + + +_Suborder_ MYSTACOCETI, _the_ BALÆNOIDEA, _Whalebone, or True +Whales_.[128] + + +_Family_ BALÆNIDÆ. + +Teeth never functionally developed, but always disappearing before the +close of intra-uterine life. Palate provided with plates of baleen +or “whalebone.” Skull symmetrical. Nasal bones forming a roof to the +anterior nasal passages, which are directed upwards and forwards. +Maxilla produced in front of, but not over, the orbital process of the +frontal. Lachrymal bones small and distinct from the jugal. Tympanic +bone involuted (Fig. 76), and ankylosed with the periotic, which is +attached to the base of the cranium by two strong diverging processes. +Olfactory organ distinctly developed. Rami of mandible arched outwards, +their anterior ends meeting at an angle, and connected by fibrous tissue +without any true symphysis. All the ribs at their upper extremities +articulating only with the transverse processes of the vertebræ; their +capitular processes, when present, not articulating directly with +the bodies of the vertebræ. Sternum composed of a single piece, and +articulating only with a single pair of ribs. No ossified sternal ribs. +External openings of nostrils distinct from each other, longitudinal. A +short conical cæcum. + +These animals have, when in the fœtal state, numerous minute calcified +teeth lying in the dental groove of both upper and lower jaws. They are +best developed about the middle of fœtal life, after which period they +are absorbed, and no trace of them remains at the time of birth.[129] The +baleen or whalebone does not make its appearance until after birth. It +consists of a series of flattened horny plates, between three and four +hundred in number, on each side of the palate, with a bare interval along +the middle line. These plates are placed transversely to the long axis of +the palate, with very short intervals between them. Each plate or blade +is somewhat triangular in form, with the base attached to the palate +and the apex hanging downwards. The outer edge of the blade is hard and +smooth; but the inner edge and apex fray out into long bristly fibres, +so that the roof of the Whale’s mouth looks as if covered with hair, as +described by Aristotle. At the inner edge of each principal blade are +two or three much smaller or subsidiary blades. The principal blades are +longest near the middle of the series, and gradually diminish towards the +front and back of the mouth. The horny plates grow from a dense fibrous +and highly vascular matrix, covering the palatal surface of the maxillæ, +and sending out lamellar processes, one of which penetrates the base of +each blade. Moreover, the free edge of these processes is covered with +very long vascular thread-like papillæ, one of which forms the central +axis of each of the hair-like epidermic fibres of which the blade is +mainly composed. A transverse section of fresh whalebone shows that it is +made up of numbers of these soft vascular papillæ, circular in outline, +each surrounded by concentrically arranged epidermic cells, and the whole +bound together by other epidermic cells, that constitute the smooth +cortical (so-called “enamel”) surface of the blade, which, disintegrating +at the free edge, allows the individual fibres to become loose and +assume the hair-like appearance before spoken of. These fibres differ +from hairs in not being formed in depressed follicles in the enderon, +but rather resemble the fibres composing the horn of the Rhinoceros. +The whalebone in fact consists of nothing more than modified papillæ of +the buccal mucous membrane, with an excessive and cornified epithelial +development. The blades are supported and bound together for a certain +distance from their base by a mass of less hardened epithelium, secreted +by the surface of the palatal membrane or matrix of the whalebone in +the intervals of the lamellar processes. This is the “intermediate +substance” of Hunter, the “gum” of the whalers. Baleen varies much in +colour in different species. In some it is almost jet black, in others +slate-colour, horn-colour, yellow, or even creamy-white. In some the +blades are variegated with longitudinal strips of different hues. Baleen +differs also greatly in other respects, being short, thick, coarse, and +stiff in some, and greatly elongated and highly elastic in those species +in which it has attained its fullest development. Its function is to +strain the water from the small marine molluscs, crustaceans, or fish +upon which the Whales subsist. In feeding the immense mouth is filled +with water containing shoals of these small creatures, and then, on the +Whale closing the jaws and raising the tongue, so as to diminish the +cavity of the mouth, the water streams out through the narrow intervals +between the hairy fringe of the whalebone blades, and escapes through the +lips, leaving the living prey to be swallowed.[130] + +Our knowledge of the different structural modifications attained by +members of this important group of mammals, though largely increased +of late years, is still imperfect. Formerly they were all divided into +Right Whales (_Balæna_) and Rorquals or Fin-Whales (_Balænoptera_), the +latter distinguished by their smaller heads, elongated and slender form, +free cervical vertebræ, tetradactylous manus, and the presence of very +conspicuous longitudinal furrows or folds in the skin of the throat +and chest, and of a small adipose dorsal fin. Recent discoveries have, +however, brought to light several forms holding a somewhat intermediate +position, and presenting combinations of characters not found in either +of the longer known sections. According to our present knowledge the +group is naturally divided into five very distinct genera, of which the +leading characters are given below. + +_Balæna._[131]—Skin of throat smooth, not furrowed. No dorsal fin. +Cervical vertebræ united into a single mass. Pectoral limb short, broad, +and pentadactylous. Head very large. Baleen very long and narrow, highly +elastic, and black. Scapula high, with a distinct coracoid and acromion +process. Tympanic (Fig. 78) deep and angular, its inflation comparatively +slight, and the involuted portion not fig-shaped, and frequently without +a well-marked depression at the anterior extremity of the superior border +of the inner surface for the Eustachian canal. + +[Illustration: FIG. 76.—Greenland or Arctic Right Whale (_Balæna +mysticetus_).] + +The Greenland, or more properly Arctic, Right Whale (_Balæna mysticetus_) +attains, when full grown, a length of from 45 to 50 feet. Its usual +vertebral formula is C 7, D 12, L 14, C 22. The external form is shown +in Fig. 76 from a careful drawing by Mr. Robert Gray. In this species +all the peculiarities which distinguish the head and mouth of the Whales +from those of other mammals have attained their greatest development. +The head is of enormous size, exceeding one-third of the whole length +of the creature. The cavity of the mouth is actually larger than that +of the body, thorax and abdomen together. The upper jaw is very narrow, +but greatly arched from before backwards, to increase the height of the +cavity and allow for the great length of the baleen blades; the rami of +the mandible are widely separated posteriorly, and have a still further +outward sweep before they meet at the symphysis in front, giving the +floor of the mouth the shape of an immense spoon. The baleen blades +attain the number of 380 or more on each side, those in the middle of +the series having a length of 10 or sometimes 12 feet. They are black in +colour, fine and highly elastic in texture, and fray out at the inner +edge and ends into long, delicate, soft, almost silky, but very tough, +hairs. The remarkable development of the mouth and the structures in +connection with it, which distinguishes the Right Whale among all its +allies, is entirely in relation to the nature of its food. It is by this +apparatus that the animal is enabled to avail itself of the minute but +highly nutritious crustaceans and pteropods which swarm in immense shoals +in the seas it frequents. The large mouth enables it to take in at one +time a sufficient quantity of water filled with these small organisms, +and the length and delicate structure of the baleen provide an efficient +strainer or hair-sieve by which the water can be drained off. If the +baleen were rigid, and only as long as is the aperture between the upper +and lower jaws when the month is shut, a space would be left beneath it +when the jaws were separated, through which the water and the minute +particles of food would escape together. But instead of this the long, +slender, brush-like, elastic ends of the whalebone blades fold back when +the mouth is closed, the front ones passing below the hinder ones in a +channel lying between the tongue and the lower jaw. When the month is +opened, their elasticity causes them to straighten out like a bow unbent, +so that at whatever distance the jaws are separated the strainer remains +in perfect action, filling the whole of the interval. The mechanical +perfection of the arrangement is completed by the great development of +the lower lip, which rises stiffly above the jaw-bone and prevents the +long, slender, flexible ends of the baleen from being carried outwards by +the rush of water from the mouth, when its cavity is being diminished by +the closure of the jaws and raising of the tongue. + +If, as appears highly probable, the “bowhead” of the Okhotsk Sea and +Behring Strait belongs to this species, its range is circumpolar. Though +found in the seas on both sides of Greenland, and passing freely from +one to the other, it is never seen so far south as Cape Farewell; but on +the Labrador coast, where a cold stream sets down from the north, its +range is somewhat farther. In the Behring Sea, according to Scammon, “it +is seldom seen south of the fifty-fifth parallel, which is about the +farthest southern extent of the winter ice, while on the Sea of Okhotsk +its southern limit is about the latitude of 54°.” As has been abundantly +shown by Eschricht and Reinhardt in the case of the Greenland seas, +“everything tends to prove,” Scammon says, “that the _Balæna mysticetus_ +is truly an ‘ice whale,’ for among the scattered floes, or about the +borders of the ice-fields or barriers, is its home and feeding-ground. +It is true that these animals are pursued in the open water during +the summer months; but in no instance have we learned of their being +captured south of where winter ice-fields are occasionally met with.” The +occurrence of this species, therefore, on the British or any European +coast is exceedingly unlikely, as when alive and in health the southern +limit of its range in the North Sea has been ascertained to be from the +east coast of Greenland at 64° N. lat. along the north of Iceland towards +Spitsbergen, and a glance at a physical chart will show that there are +no currents setting southwards which could bear a disabled animal or a +floating carcase to British shores. To this _à priori_ improbability may +be added the fact that no authentic instance has been recorded of the +capture or stranding of this species upon any European coast; for the +cases in which it has been reported as seen in British waters may be +explained by the supposition of one of the other species of the genus +being mistaken for it. Still, as two other essentially Arctic Cetaceans, +the Narwhal and the Beluga, have in a few undoubted instances found +their way to British shores, it would be rash absolutely to deny the +possibility of the Greenland Right Whale doing the same. + +[Illustration: FIG. 77.—Southern Right Whale (_Balæna australis_).] + +The southern Right Whale (_B. australis_, Fig. 77) resembles the last +in the absence of dorsal fin and of longitudinal furrows in the skin of +the throat and chest, but differs in that it possesses a smaller head +in proportion to its body, shorter baleen, a different shaped contour +of the upper margin of the lower lip, and a greater number (fifteen) of +ribs and dorsal vertebræ. This form inhabits the temperate seas of both +northern and southern hemispheres, and is divided into several so-called +species, according to their geographical distribution:—_B. biscayensis_ +of the North Atlantic, _B. japonica_ of the North Pacific, _B. australis_ +of the South Atlantic, and _B. antipodarum_ and _B. novæ-zealandiæ_ of +the South Pacific. The differential characters by which they have been +separated, external as well as anatomical, are, however, slight and +subject to individual variation; and the number of specimens available +for comparison in museums is not yet sufficient to afford the necessary +data to determine whether these characters can be regarded as specific +or not. The most interesting of these is the Atlantic Right Whale, which +was formerly abundant in the North Atlantic, but is now so scarce as to +appear verging on extinction. This was the Whale the pursuit of which +gave occupation to a numerous population on the shores of the Basque +provinces of France and Spain in the Middle Ages. From the tenth to +the sixteenth centuries Bayonne, Biarritz, St. Jean de Luz, and San +Sebastian, as well as numerous other towns on the north coast of Spain, +were the centres of an active Whale “fishery,” which supplied Europe +with oil and whalebone. In later times these Whales were pursued as +far as the coast of Newfoundland. They were, however, already getting +scarce when the voyages undertaken towards the close of the sixteenth +century for the discovery of the north-eastern route to China and the +East Indies opened out the seas around Spitzbergen; then for the first +time the existence of the Greenland Whale became known, and henceforth +the energies of the European whale-fishers were concentrated upon that +animal. It is a singular fact that the existence of the Atlantic Right +Whale was quite overlooked by naturalists till lately, all accounts +referring to it being attributed to the Greenland Whale, supposed once to +have had a wider distribution than now, and to have been driven by the +persecution of man to its present circumpolar haunts. To the two Danish +cetologists Eschricht and Reinhardt is due the credit of having proved +its existence as a distinct species, from a careful collation of numerous +historical notices of its structure, distribution, and habits; and +their restoration of the animal, founded upon these documents, has been +abundantly confirmed by the capture of various specimens in recent times, +showing that it still lingers in some of the localities where it formerly +was so abundant. The only known instances of its occurrence on the coasts +of Europe in modern times are in the harbour of San Sebastian in January +1854, in the Gulf of Taranto, in the Mediterranean, in February 1877, and +on the Spanish coast between Guetaria and Zarauz (Guipuzcoa) in February +1878. The skeletons of these three whales are preserved in the museums +of Copenhagen, Naples, and San Sebastian respectively. On the coast of +the United States several Whales of this species have been taken within +the last few years. In the North Pacific a very similar if not identical +species is regularly hunted by the Japanese, who tow the carcases +ashore for the purposes of flensing and extracting the whalebone. In +the tropical seas, however, according to Captain Maury’s whale charts, +Right Whales are never or rarely seen; but the southern temperate ocean, +especially the neighbourhood of the Cape of Good Hope, Kerguelen’s +Island, Australia, and New Zealand, is inhabited by “Black Whales,” once +abundant, but now nearly exterminated through the wanton destruction of +the females as they visit the bays and inlets round the coast, their +constant habit in the breeding time. The range of these Whales southward +has not been accurately determined; but no species corresponding with the +Arctic Right Whale has as yet been met with in the Antarctic icy seas. + +[Illustration: FIG. 78.—The right tympanic bone of an immature individual +of the Greenland Whale (_Balæna mysticetus_), from the inner (_A_) and +outer (_B_) aspects. ¹⁄₃ natural size. (From the _Proc. Zool. Soc._)] + +Remains of Right Whales are of not uncommon occurrence in the Pliocene +Crag deposits of England and Belgium. The tympanics of _B. affinis_ +from these deposits appear to indicate a species closely allied to +_B. mysticetus_, in which this bone is long and angulated anteriorly +(Fig. 78); while the tympanics from the same deposits described as _B. +primigenia_ are shorter and more rounded at the antero-inferior angle, +thus resembling those of _B. australis_. A smaller species, having an +estimated length of about 20 feet, has been described as _Balænula +balænopsis_, the generic distinction being made on account of the free +condition of the atlas and seventh cervical vertebræ; but it seems +scarcely advisable to regard such a feature as indicating more than a +less specialised species. _Balæna (Balænotus) insignis_ is a whale of +somewhat larger dimensions, in which the atlas is generally, and the +seventh cervical vertebra always, free, while in young individuals the +axis vertebra may likewise be separate. + +_Neobalæna._[132]—Head about one-fourth the total length. Skin of the +throat not plicated. A small falcate dorsal fin. Vertebræ, C 7, D 17, L +3, C 16 = 43. The cervical vertebræ are united. The manus small, narrow, +and tetradactylous, wanting the pollex. The ribs remarkably expanded and +flattened. The scapula very low and broad, with completely developed +acromion and coracoid processes. Tympanic approximating to that of +_Balæna_, but with certain very characteristic peculiarities of shape. +Baleen very long, slender, elastic, and white. A single species, at +present very rare, _N. marginata_, from the Australian and New Zealand +seas is the smallest of the Whalebone Whales, being not more than 20 feet +in length. + +_Rhachianectes._[133]—This combines the small head, elongated form, and +narrow pectoral fin of _Balænoptera_ with the smooth skin of the throat +and absence of the dorsal fin of _Balæna_. The baleen is the shortest and +coarsest of any of the group. Its osteology is imperfectly known. One +species, _R. glaucus_, the Gray Whale of the North Pacific. + +_Megaptera._[134]—Head of moderate size. Baleen plates short and broad. +Vertebræ, C 7, D 14, L 11, C 21 = 53. Cervical vertebræ free. Scapula +with acromion and coracoid process absent or rudimentary. Skin of throat +plicated. Dorsal fin low. Pectoral limb tetradactylous, very long and +narrow, attaining about one-fourth of the length of the entire animal, +the metacarpus and phalanges being greatly developed, and the latter very +numerous. Tympanic still more inflated than in _Balænoptera_, with the +involuted portion more distinctly pyriform, the Eustachian part of the +aperture well defined, and two well-marked longitudinal ridges on the +lower surface of adult specimens. + +The Whale commonly called “Humpback” (_Megaptera boops_) by whalers, +perhaps on account of the low hump-like form of the dorsal fin, is very +distinctly characterised from all others of the group, especially by the +immense length of the pectoral fins or flippers, which are indented or +scalloped along their margins, and are, except at their base, of a white +colour, nearly all the rest of the body being black. The baleen plates +are of a deep black colour. Though common in the North Atlantic between +Norway and Greenland, this Whale does not frequently appear on the coasts +of the British Isles. One came ashore at Newcastle in 1839; another, a +young one, was taken in the estuary of the Dee in 1863, and its skeleton +is preserved in the Liverpool museum; and a nearly full-grown animal +was captured in the mouth of the Tay in the winter of 1883-84.[135] +The usual length of the adult ranges from 45 to 50 feet, the female +being larger than the male. Whales of the genus _Megaptera_ are found +in the South Atlantic and in both the North and the South Pacific. They +resemble those of British seas so closely that it is doubtful whether the +differences which have been observed, and upon which several species have +been founded, may not be individual peculiarities; but zoologists have +not yet had the opportunity of examining and comparing such a series of +specimens of different ages and sexes from different localities as would +be necessary to determine these points satisfactorily. + +[Illustration: FIG. 79.—Humpbacked Whale (_Megaptera boops_).] + +Tympanic bones of _Megaptera_ occur in the English and Belgian Crags, +although somewhat less commonly than those of _Balæna_ and _Balænoptera_; +they have been described under the names of _Megapteropsis_ and +_Burtinopsis_. + +[Illustration: FIG. 80.—The Common Rorqual (_Balænoptera musculus_).] + +_Balænoptera._[136]—Head small and flat, and pointed in front. Body long +and slender. Skin of throat plicated. A small falcate dorsal fin. Baleen +short and coarse. Cervical vertebræ free. Scapula low and broad, with a +large acromion and coracoid process. Pectoral limb tetradactylous, small, +narrow, and pointed. Tympanic (Fig. 81) long, much inflated, and rounded, +with the involuted portion thickened and pyriform, and the notch for the +Eustachian canal sharply defined; inner surface flattened, without the +vertical groove found in _Megaptera_. + +[Illustration: FIG. 81.—The right tympanic of _Balænoptera musculus_ from +the inner (A) and outer (B) aspects. ½ natural size. (From the _Proc. +Zool. Soc._)] + +The Rorquals, Fin-Whales, Fin-backs, Finners, or Razor-backs, as they +are variously called, have the plicated skin of the throat like that +of _Megaptera_, the furrows being more numerous and close set; but the +pectoral fin is comparatively small, the dorsal fin distinct and falcate, +and the tail very much compressed before it expands into the “flukes.” +The Rorquals are perhaps the most abundant and widely distributed of +all the whales, being found in some of their modifications in all seas, +except the extreme Arctic, and probably Antarctic regions. Owing to the +small quantity and inferior quality of their whalebone, the comparatively +limited amount of blubber, and their great activity and the difficulty of +capturing them by the old methods, these Whales were not until recently +an object of pursuit by whale-fishers; but, since the introduction of +steam-vessels, and especially of explosive harpoons fired from guns in +the place of those hurled by the human hand, a regular fishery has been +established on the coast of Finmark. There are four distinct species +of this genus in British seas. (1) _Balænoptera sibbaldi_, the “Blue +Whale,” the largest of all known animals, attains a length of 80 or even +sometimes 85 feet. Its colour is dark bluish gray, with small whitish +spots on the breast; the baleen is black; the flippers are larger +proportionally than in other Rorquals, measuring one-seventh of the +total length of the body; and the dorsal fin is small and placed very +far back. This Whale has usually 64 vertebræ, of which 16 bear ribs. +Like the others of the genus, this species seems to pass the winter in +the open seas, and approaches the coast of Norway at the end of April +or beginning of May. At this time its sole food is a small crustacean +(_Euphausia inermis_) which swarms in the fjords. Several specimens have +been taken on the British coasts, two fine skeletons from the Firth +of Forth being preserved in the Edinburgh museums. (2) _Balænoptera +musculus_, the Common Rorqual, has a length of 65 to 70 feet, is of a +grayish slate colour above and white underneath, and the baleen is slate +colour variegated with yellow or brown. It has usually 62 vertebræ, of +which 15 bear ribs. This is the commonest of all the large Whales on +the British coasts, scarcely a winter passing without the body of one +being somewhere washed ashore, usually after stormy weather, and more +frequently on the south coast, as this species has a more southern range +than the last, and frequently enters the Mediterranean. It feeds largely +on fish, and is frequently seen feasting among shoals of herring. (3) +_Balænoptera borealis_, often called Rudolphi’s Whale from its first +describer, is a smaller species, scarcely attaining a length of 50 feet. +It is bluish-black above, with oblong, light-coloured spots, whilst +the under parts are more or less white; the whole of the tail and both +sides of the flippers are black; the baleen is black, and the bristly +ends fine, curling, and white; the flippers are very small, measuring +one-eleventh of the total length of the body. There are 56 vertebræ, +with 14 pairs of ribs. This species, according to Collett, feeds chiefly +on minute crustaceans, mainly _Calanus finmarchicus_ and _Euphausia +inermis_, and not on fish. Until lately it was considered the rarest of +the Whales of European seas, and was only known to science from a few +individuals stranded on the coasts of northern Europe at long intervals, +the skeletons of which have been preserved in museums. The most southern +point at which it has been met with hitherto is Biarritz in France. Since +the establishment of the whaling station near the North Cape it has been +shown to be a regular summer visitor, and in 1885, 771 individuals were +captured on the coast of Finmark. (4) _Balænoptera rostrata_, the lesser +Fin-Whale or Rorqual, is the smallest species found in the northern seas, +rarely exceeding 30 feet in length. Its colour is grayish-black above, +whilst the under side is white, including the whole of the lower side of +the tail; the inner side of the flippers is white; and there is a broad +white band across the outer side, which is a very characteristic mark of +the species; the baleen is yellowish-white. The dorsal fin in this and +the last species is comparatively high, and placed far forwards on the +body. This Whale has usually 48 vertebræ, 11 of which bear ribs. It is +common in summer in the fjords of Norway, and is often seen around the +British Isles. It has been taken, though rarely, in the Mediterranean; +and ranges as far north as Davis’s Straits. + +Rorquals are met with in almost all seas throughout the world, but +further and more accurate observations are required before their +specific characters and geographical distribution can be made out. Nearly +all the individuals hitherto examined with any care, whether from the +North Pacific, the Australian seas, or the Indian Ocean, come very near +in structure to one or the other of the Atlantic forms described above, +so much so that some zoologists have been induced to believe that there +are but four species, each of which has a wide, almost cosmopolitan +range, while others have described and named almost every individual +specimen captured as belonging to a different species.[137] + +Tympanics, vertebræ, and other bones of Rorquals are among the commonest +cetacean remains found in the Pliocene Crags of England and Belgium. +Several species, varying in dimensions, are known from these deposits, +_B. definita (sibbaldina)_ being apparently nearly related to the +existing _B. sibbaldi_. A caudal vertebra from the Upper Eocene of +Hampshire has been referred to _Balænoptera_, but does not afford +sufficient evidence to prove the existence of the genus at that date. + +_Extinct Genera._—The extinct genus _Cetotherium_ of the European +Pliocene may be taken to include a number of fossil Whalebone Whales +allied to the Balænopterine group, several of which have been +described under other names, such as _Plesiocetus_, _Heterocetus_, and +_Amphicetus_. They are readily characterised by the form of the tympanic +bone, which is much narrower in front than behind, the roughened inferior +surface being in the shape of an isosceles triangle, and the notch for +the Eustachian canal being smaller, and descending nearer to the inferior +border of the inner wall than in _Balænoptera_. The skull is longer than +the latter, with a greater interval between the occiput and the frontal, +and with longer and more flattened nasals. The relative thickness of +the cervical vertebræ is also greater. In the typical forms (_e.g._ _C. +brialmonti_ and _C. dubium_) the mandibular condyle is simple; but in _C. +(Heterocetus) brevifrons_ it is furnished with a projecting posterior +talon, as in the Sperm Whale. + +_Herpetocetus_ is known by a comparatively small species from the +Belgian and English Crags, characterised by the extreme inflation of the +egg-shaped tympanic bone, which approximates to that of _Megaptera_, but +has the greater part of the cavity filled by bone. There is a talon to +the condyle of the mandible. + +_Palæocetus_, as already mentioned (p. 232), is founded upon the +ankylosed cervical vertebræ of a small Whale originally considered as +having been derived from the Kimeridge Clay, but which doubtless came +from the Suffolk Crag; if it belongs to the _Balænidæ_ it indicates a +Right Whale. + + +_Suborder_ ARCHÆOCETI. + + +_Family_ ZEUGLODONTIDÆ. + +This group is formed to include certain extinct Cetacean-like animals at +present only known by more or less fragmentary portions of their skeleton +and teeth, and whose position and affinities are, therefore, still +subject to doubt.[138] + +In the anterior part of both jaws the teeth are simple, conical, or +slightly compressed, and sharp pointed. The first three in the upper jaw +are distinctly implanted in the premaxillary bone, and so may be reckoned +as incisors. The tooth which succeeds, or the canine, is also simple and +conical, but it does not exceed the others in size. This is followed by +five teeth having two distinct roots and compressed pointed crowns, with +denticulated cutting-edges. The dentition is therefore _i_ ³⁄₃, _c_ ¹⁄₁, +_p_ and _m_ ⁵⁄₅ = 36, resembling that of some Seals.[139] General form +of the skull elongated and much depressed. Brain-cavity very small, and +the skull between it and the orbits elongated and narrow. Temporal fossæ +very large. A strong sagittal crest. Rostrum long and narrow, differing +from that of other Cetaceans in the large extent to which the premaxillæ +form the sides of the anterior extremity. Nasal bones elongated, flat, +and narrow, the opening of the anterior nares being over the middle of +the elongated compressed rostrum. All the cervical vertebræ free. The +characters of the dorsal vertebræ and mode of articulation of the ribs +appear to have resembled those of _Platanista_ rather than _Balæna_, +_Physeter_, or _Delphinus_. Lumbar vertebræ with elongated bodies, low +neural spines, and the transverse processes placed low down on the +bodies. Characters of the limbs not known with certainty.[140] + +All the known fossil remains belonging to the animals of this group may +be referred, provisionally at least, to the genus _Zeuglodon_, so named +because the first section of a molar tooth examined was taken from the +base of the crown, where it was beginning to divide into the two roots, +and looked like two single teeth “linked or yoked together.” This name +was substituted by Owen for the earlier one _Basilosaurus_ of Harlan, +with the consent of that author, on the mammalian nature of the animal +being demonstrated.[141] The latter name is, however, still generally +retained by American zoologists. The remains have hitherto been found +chiefly in the Eocene formations of the States of Alabama, Louisiana, +Mississippi, and Arkansas, and have been assigned to several species. +A portion of a skull is recorded from the Barton Clay (Eocene) of +Hampshire, England. + + +_Suborder_ ODONTOCETI, _the_ DELPHINOIDEA, _or Toothed Whales_. + +Calcified teeth always present after birth; generally numerous, but +sometimes a very limited number (in a few cases none) are functionally +developed. No baleen. Upper surface of the skull more or less +asymmetrical. Nasal bones in the form of nodules or flattened plates, +applied closely to the frontals, and not forming any part of the roof to +the narial passage, which is directed upwards and backwards. Olfactory +organ rudimentary or absent. Hinder end of the maxilla expanded and +covering the greater part of the orbital plate of the frontal bone. +Lachrymal bone either inseparable from the jugal, or, when distinct, +very large, and forming part of the roof of the orbit. Tympanic bone +not ankylosed with the periotic, which is usually only attached to the +rest of the skull by ligament. Rami of mandible nearly straight, much +expanded in height posteriorly, with a wide funnel-shaped aperture to +the dental canal, and coming in contact in front by a flat surface of +variable length, but always constituting a true symphysis. Several of the +anterior ribs with well-developed capitular processes, articulating with +the bodies of the vertebræ. Sternum almost always composed of several +pieces, placed one behind the other, with which several pairs of ribs +are always connected by the intervention of well-developed cartilaginous +or ossified sternal ribs. External respiratory aperture single, the two +nostrils uniting before they reach the surface, usually in the form of a +transverse subcrescentic valvular aperture, situated on the top of the +head. Manus always pentadactylous, though the first and fifth digits are +usually very little developed. No cæcum, except in _Platanista_. + + +_Family_ PHYSETERIDÆ. + +No functional teeth in the upper jaw. Mandibular teeth various, often +much reduced in number. Bones of the cranium raised so as to form an +elevated prominence or crest behind the nares. Pterygoid bones thick, +produced backwards, meeting in the middle line, and not involuted to form +the outer wall of the post-palatine air-sinuses, but simply hollowed +on their outer side. Anterior facet of periotic bone (Fig. 87) for +articulation with the tympanic quite smooth; and the posterior tympanic +surface of the former broad, with a median longitudinal ridge. Transverse +processes of the arches of the dorsal vertebræ, to which the tubercles +of the ribs are attached, ceasing abruptly near the end of the series, +and replaced by processes on the body at a much lower level, and not on a +line or serially homologous with them, but serially homologous anteriorly +with the heads of the ribs, and posteriorly with the transverse +processes of the lumbar vertebræ. (In some genera, as _Physeter_, the +two processes, upper and lower on each side, are both present and well +developed in the same vertebra in the region of transition. In others, +as _Ziphius_ and _Berardius_, they are not both developed on any single +vertebra.) Costal cartilages not ossified. + +Subfamily =Physeterinæ=.—Numerous teeth in the mandible, which are not +set in distinct bony alveoli, but in a long groove imperfectly divided by +partial septa, and held in place by the strong, fibrous gum surrounding +them. No distinct lachrymal bone. Cranium strikingly asymmetrical in +the region of the narial apertures, in consequence of the left opening +greatly exceeding the right in size. + +[Illustration: FIG. 82.—Skull of Sperm Whale (_Physeter macrocephalus_).] + +_Physeter._[142]—Upper teeth apparently of uncertain number, rudimentary, +and functionless, being embedded in the gum. Lower jaw with from 20 to +25 teeth on each side, stout, conical, recurved, and pointed at the +apex until they are worn, without enamel. Upper surface of the cranium +concave; its posterior and lateral edges raised into a very high and +greatly compressed semicircular crest or wall. Zygomatic processes of +jugal bones thick and massive. Rostrum greatly elongated, broad at the +base, and gradually tapering to the apex. Upper edge of the mesethmoid +forming a roughened irregular projection between the narial apertures, +inclining to the left side. Mandible exceedingly long and narrow, the +symphysis being more than half the length of the ramus. Vertebræ: C 7, +D 11, L 8, C 24; total 50. Atlas free; all the other cervical vertebræ +united by their bodies and spines into a single mass. Eleventh pair of +ribs rudimentary. Head about one-third the length of the body; very +massive, high and truncated, and rather compressed in front; owing its +huge size and remarkable form mainly to the accumulation of an oily +substance secreted by the lining membranes of great cells surrounding the +narial passage and filling the large hollow on the upper surface of the +cranium and overlying the rostrum. The single blowhole is longitudinal, +slightly sigmoid, and placed at the upper and anterior extremity of the +head to the left side of the middle line. The opening of the mouth is on +the under side of the head, considerably behind the end of the snout. +Pectoral fin short, broad, and obliquely truncated. Dorsal fin a mere low +protuberance. + +[Illustration: FIG. 83.—The Sperm Whale (_Physeter macrocephalus_).] + +The only representative of this genus is the Cachalot or Sperm Whale (_P. +macrocephalus_, Fig. 83), one of the most colossal of animals, quite +equalling, if not exceeding, the Greenland Whale in bulk. The length of +the full-grown male is from 55 to 60 feet, but the female is stated not +to reach more than half that size. The general colour of the surface +is black above and gray below, the colours gradually shading into each +other. The Sperm Whale is one of the most widely distributed of animals, +being met with usually in herds or “schools” in almost all tropical and +subtropical seas, but not occurring, except accidentally, in the Polar +regions. Not unfrequently specimens appear on the coasts of the British +Isles, but only as solitary stragglers, or as dead carcases, floated +northwards by the Gulf Stream. It is remarkable that every one of these +of which we have an accurate record has been an old male. The food of +this Whale consists mainly of various species of cephalopods (squid and +cuttle-fish), but fish of considerable size are also eaten. The substance +called “ambergris,” formerly used in medicine and now in perfumery, is a +concretion formed in the intestine of this Whale, and is found floating +on the surface of the seas it inhabits. Its genuineness is proved by the +presence of the horny beaks of the cephalopods on which the Whale feeds. + +The oil contained in the great cavity above the skull, when refined, +yields “spermaceti,” and the thick covering of blubber which everywhere +envelops the body produces the valuable “sperm-oil” of commerce; hence +this animal has long been the subject of a regular chase, by which its +numbers have been greatly diminished. + +_Cogia._[143]—Teeth of the upper jaw absent, or reduced to a rudimentary +pair in front; in the lower jaw 9 to 12 on each side, rather long, +slender, pointed, and curved, with a coating of enamel. Upper surface +of the cranium concave, with thick, raised posterior and lateral +margins, massive and rounded at their anterior terminations above the +orbits. Upper edge of the mesethmoid forming a prominent sinuous ridge, +constituting a kind of longitudinal septum to the base of the great +supra-cranial cavity. Rostrum not longer than the cranial portion of the +skull, broad at the base, and rapidly tapering to the apex. Zygomatic +process of the jugal styliform. Mandible with the symphysis less than +half the length of the entire ramus. Vertebræ: C 7, D 13 or 14, L and C +30; total 50 or 51. All the cervical vertebræ united by their bodies and +arches. External characters not well known, but, judging by the somewhat +conflicting accounts of those that have had an opportunity of observing +them, the head is about one-sixth of the length of the body, and obtusely +pointed in front; the mouth small, and placed far below the apex of the +snout; the spiracle crescentic, and placed obliquely on the top of the +head anteriorly to the eyes, and to the left of the middle line; the +pectoral fins are obtusely falcate; and there is a triangular dorsal fin. + +The history of this genus is a good illustration of the difficulties +in which the study of the Cetacea has been involved by the superficial +manner in which it has been investigated. The first known example, a +skull from the Cape of Good Hope in the Paris Museum, was described by De +Blainville under the name of _Physeter breviceps_. This was afterwards +with good reason generically separated by Gray. Until within a very +few years ago only five other individuals had been met with, each of +which had been described under a different specific name (viz. _grayi_, +_macleayi_, _simus_, _floweri_, and _potsii_), and which are arranged +by Gray in two distinct genera. The most careful examination of the +description given of these specimens, or of the now numerous osteological +remains available, fails to detect any differences beyond those which +may be attributed to age or sex, and hence, according to our present +knowledge, these six supposed species must all be included under one +name, _C. breviceps_. This animal appears to attain the length of 10 feet +when adult, and has been met with at various distant localities in the +Southern Ocean, and also off the coast of Madras and in the North Pacific. + +_Extinct Physeteroids._—Teeth of Physeteroids are of very common +occurrence in the Belgian and English Crags, and evidently indicate the +former existence of Whales more or less closely allied to the Sperm +Whale, but often distinguished by the presence of an enamel-cap on +the crowns of the teeth. The generic determination of these teeth is, +however, exceedingly difficult, owing to the water-worn condition in +which they are frequently found, and also on account of the impossibility +of knowing whether small and large teeth may not be referable to +different parts of the jaws of the same species or to individuals of +different ages. Moreover, in the cases of isolated teeth it is impossible +to know how many were contained in the jaws, and therefore to distinguish +Physeteroid from Ziphioid teeth. _Physeterula_ is a small form about +one-third the dimensions of the Sperm Whale, and distinguished by the +length of the mandibular symphysis being only about one-third that of the +entire ramus; it is identified by Professor Cope with _Cogia_. _Eucetus_ +(_Dinoziphius_) is founded on teeth which are regarded as closely +resembling those of _Physeter_, but distinguished by their subcylindrical +form and the small size of the aperture of the pulp-cavity. It does not +appear, however, to be certain that these teeth are not worn specimens +of those described as _Scaldicetus_. _Physetodon_, from the Pliocene of +Australia, is founded upon the evidence of similar teeth. The teeth from +the Belgian Crag described as _Scaldicetus_ are somewhat smaller than +those of the Sperm Whale, and are readily characterised by their cap +of grooved enamel. Other teeth with enamel-caps have been described as +_Physodon_ and _Hoplocetus_. The genus _Balænodon_ is founded upon a very +imperfect large tooth from the English Crag, which is not sufficiently +well preserved to admit of exact comparison with the other types. + +Subfamily =Ziphiinæ=.—Teeth of the mandible (at least in existing forms) +quite rudimentary and concealed in the gum, except one, or very rarely +two, pairs which may be largely developed, especially in the male sex. +A distinct lachrymal bone. Externally the mouth is produced into a +slender rostrum or beak, from above which the rounded eminence formed by +a cushion of fat resting on the cranium in front of the blowhole rises +somewhat abruptly. Spiracle or blowhole single, crescentic, median, as +in the _Delphinidæ_. Pectoral fin small, ovate, the five digits all +moderately well developed. A small obtusely falcate dorsal fin situated +considerably behind the middle of the back. Longitudinal grooves on +each side of the skin of the throat, diverging posteriorly, and nearly +meeting in front. In external characters and habits the animals of this +group closely resemble each other. They appear to be almost exclusively +feeders on various species of cephalopods, and occur either singly, in +pairs, or in small herds. By their dental and osteological characters +they are easily separated into four distinct genera. + +_Hyperoödon._[144]—A small conical pointed tooth at the apex of each +ramus of the mandible, concealed by the gum during life. Skull with the +upper ends of the premaxillæ rising suddenly behind the nares to the +vertex and expanded laterally, their outer edges curving backwards and +their anterior surfaces arching forwards and overhanging the nares; the +right larger than the left. Nasal bones lying in the hollow between the +upper extremities of the premaxillæ, strongly concave in the middle line +and in front; their outer edges, especially on the right side, expanded +over the front of the inner border of the maxilla. Very high longitudinal +crests on the maxillæ at the base of the rostrum, extending backwards +almost to the nares, approaching each other in the middle line above; +sometimes so massive that their inner edges come almost in contact. +Anteorbital notch distinct. Mesethmoid but slightly ossified. Vertebræ: +C 7, D 9, L 10, C 19; total 45. All the cervical vertebræ united. Upper +surface of the head in front of the blowhole hole very prominent and +rounded, rising abruptly from above the small, distinct snout. + +[Illustration: FIG. 84.—_Hyperoödon rostratus._ From a female specimen +taken off the coast of Scotland, 1882.] + +The genus is known typically by _H. rostratus_ (Fig. 84), but an +imperfect skull has been made the type of _H. planifrons_—a species +differing considerably in cranial characters from the typical one. The +females and young males of the first-named species have the contour of +the head of the same general form as in Fig. 84; the premaxillary crests +of the cranium being widely separated from one another, and terminating +in comparatively sharp edges. In the males, however, as age advances the +summits of these crests become gradually expanded and flattened, till +they are almost or quite in contact in the middle line. This development +of the maxillary crests produces a corresponding elevation and flattening +of the front of the head, so that in very old males this aspect presents +a flattened disc-like surface rising abruptly from the beak (which thus +becomes almost buried) and situated in a plane nearly at right angles to +the line of the back.[145] So different, indeed, is the appearance of the +skull of an old male from that of a female individual that it was long +considered that they belonged to different species—the male form having +been described as _H. latifrons_. The length of an adult male reaches 30 +feet, while that of the female does not exceed 24 feet. + +The Hyperoödon, sometimes called “Bottlenose,” a name also vaguely given +to several species of Dolphin, is a regular inhabitant of the North +Atlantic, passing the summer in the Spitzbergen seas and going farther +south in winter. It resembles the Sperm Whale in possessing a large +store of oil in the upper part of the head, which yields spermaceti when +refined; on this account, and also for the sake of the blubber, which +supplies an oil almost indistinguishable from sperm-oil, this Whale has +been the object of a regular chase in recent years. + +The following account of its habits is taken from a paper by Captain D. +Gray, published in the _Zoological Society’s Proceedings_ for 1882:— + +“These Whales are occasionally met with immediately after leaving the +Shetland Isles in March, and north across the ocean until the ice is +reached, near the margin of which they are found in the greatest numbers; +but they are seldom seen amongst it. Although it is not in their nature +to keep in amongst the ice, they like to frequent the open bays for the +shelter it gives them from the sea. Sometimes a point of ice overlaps +them; it is then only that they are seen going out again towards the +ocean. They are also to be met with from the entrance of Hudson’s Straits +and up Davis’s Straits, as far as 70° N. lat., and down the east side +round Cape Farewell, all round Iceland, north along the Greenland ice +to 77° N. lat.; also along the west coast of Spitzbergen, and east to +Cherry Island in lat. 72° N. and long. 19° E. Beyond these limits I +have never seen them; but doubtless they are to be found as far as the +Straits of Belle Isle on the west, and east to Nova Zembla. From the +fact that they are not seen in summer farther south than a day’s sail +from the ice, it would appear that they migrate south in the autumn, and +north again in the spring. They are gregarious in their habits, going +in herds of from four to ten. It is rare to see more than the latter +number together, although many different herds are frequently in sight +at the same time. The adult males very often go by themselves; but young +bulls, cows, and calves, with an old male as a leader, are sometimes seen +together. They are very unsuspicious, coming close alongside the ship, +round about underneath the boats, until their curiosity is satisfied.... +They vary in colour from black in the young to light brown in the +older animals. The very old turn almost yellow, the beak and front of +the head being quite white, with a white band round their necks; all +of them are grayish-white on the belly. They can leap many feet out +of the water, even having time while in the air to turn round their +heads and look about them, taking the water head first, and not falling +helplessly into it sideways like the larger whales. The full-grown +whale is 30 feet long by 20 feet in circumference, and yields two tons +of oil besides two hundredweight of spermaceti.... Their ordinary food +consists of a bluish-white cuttle-fish, six inches long by three inches +in circumference, and pointed towards the tail.... They evidently have a +great depth to go to find them, judging from the length of time that they +remain away, and from the long heavy blasts they make on coming to the +surface again.” + +Periotic bones of _Hyperoödon_ are found in the Red Crag of Suffolk, +presenting no character by which they can be specifically distinguished +from those of the common existing species. + +_Ziphius._[146]—A single conical tooth of moderate size on each side of +the mandible close to the anterior extremity, and directed forwards and +upwards. Skull with the premaxillæ immediately in front of, and at the +sides of the nares expanded, hollowed, and with elevated lateral margins, +the posterior ends rising to the vertex and curving forwards, the right +being considerably more developed than the left; the conjoint nasals +forming a strongly pronounced symmetrical eminence at the top of the +cranium, projecting forwards over the nares, flat above, most prominent +and rounded in the middle line in front, and separated by a notch on +each side from the premaxillæ. Anteorbital notch not distinct. Rostrum +(seen from above) triangular, gradually tapering from the base to the +apex; upper and outer edges of maxillæ at base of rostrum raised into low +roughened tuberosities. Mesethmoid cartilage densely ossified in adult +age, and coalescing with the surrounding bones of the rostrum. Vertebræ: +C 7, D 10, L 10, C 22; total 49. The three anterior cervical vertebræ +united, the rest free. + +The type of this genus is _Z. cavirostris_ of Cuvier, founded upon an +imperfect skull picked up in 1804 on the Mediterranean coast of France, +and described and figured in the _Ossemens Fossiles_ under the impression +that it was that of an extinct species. Many other individuals have, +however, been subsequently met with in various parts of the world, from +the Shetland Islands to New Zealand, all referable to the same genus, +if not to the same species; although, as is usual in such cases, they +have mostly been described under different names, the so-called genera +_Petrorhynchus_ and _Epiodon_ being probably referable to the type +species. + +It is quite probable that some of the Physeteroid teeth from the Crag +deposits mentioned on p. 251 may be referable to _Ziphius_. + +[Illustration: FIG. 85.—_Mesoplodon bidens._ From Reinhardt.] + +_Mesoplodon._[147]—A much compressed and pointed tooth in each ramus of +the mandible, variously situated, but generally at some distance behind +the apex (Fig. 86); its point directed upwards, and often somewhat +backwards, occasionally developed to a great size. Skull with the region +around the nares as in _Hyperoödon_, except that the nasals are narrow +and more sunk between the upper ends of the premaxillæ; like those of +_Hyperoödon_, they are concave in the middle line in front and above. +No maxillary tuberosities. Anteorbital notch not very distinct. Rostrum +long, narrow, and solid throughout. Mesethmoid in adult age ossified in +its entire length, coalescing with the surrounding bones, and showing as +a narrow band on the upper surface of the rostrum. Vertebræ: C 7, D 10, +L 10 or 11, C 19 or 20; total 46 to 48. Two or three anterior cervicals +united, the rest usually free. + +[Illustration: FIG. 86.—Left lateral view of skull of _Mesoplodon +densirostris_.] + +Though varying in form, the mandibular teeth of the different members +of this genus agree in their essential structure, having a small and +pointed enamel-covered crown, composed of true dentine, which, instead +of surmounting a root of the ordinary character, is raised upon a solid +mass of osteodentine. The continuous growth of this greatly alters the +form and general appearance of the organ as age advances, as seen most +strikingly in the case of _M. layardi_, where the long, narrow, flat, +strap-like teeth, curving inwards at their extremities, actually meet +over the rostrum, and must greatly interfere with the movements of the +jaw. In one species (_M. grayi_) a row of minute, conical, pointed +teeth, like those of ordinary Dolphins, 17 to 19 in number, are present +even in the adults, on each side of the middle part of the upper jaw, but +embedded by their roots only in the gum, and not in bony alveoli. This +fact, with the frequent presence of rudimentary teeth in other species of +this and the last genus in both upper and lower jaws, suggests the idea +that the Ziphioids are derived from ancestral forms which had teeth of +normal character in both jaws; the dentition of the living forms having +become greatly specialised. The existing species of this genus are widely +distributed in both northern and southern hemispheres, but most frequent +in the latter. The best established are _M. bidens_, _M. europæus_, _M. +densirostris_, _M. layardi_, _M. grayi_, and _M. hectori_; but there is +still much to be learned with regard to their distinctive characters and +geographical distribution. They were abundant in the Pliocene age, as +attested by the frequency with which the most imperishable and easily +recognised portion of their structure, the long, cylindrical rostrum +of the skull, of more than ivory denseness, is found among the rolled +and water-worn fragments of animal remains which compose the well-known +“bone-bed” at the base of the Red Crag of Suffolk Several species have +been founded upon the evidence of these rostra. Periotic bones of this +genus (Fig. 87) are of less common occurrence in the Crag; the figure +is given to illustrate the characteristic features of this bone in the +present family. + +[Illustration: FIG. 87.—The left periotic bone of _Mesoplodon_; from the +Red Crag of Suffolk. The smooth concave surface in the right upper corner +of the figure forms the anterior articulation with the tympanic. (From +the _Cat. Foss. Mamm. Brit. Mus._ pt. v. p. 70.)] + +_Berardius._[148]—Two moderate-sized, compressed, pointed teeth on +each side of the symphysis of the mandible, with their apices directed +forwards, the anterior being the larger of the two and close to the apex. +Upper ends of the premaxillæ nearly symmetrical, moderately elevated, +very slightly expanded, and not curved forward over the nares. Nasals +broad, massive, and rounded, of nearly equal size, forming the vertex +of the skull, flattened in front, most prominent in the middle line. +Anteorbital notch distinct. Rostrum long and narrow. Mesethmoid only +partially ossified. Small rugous eminences on the outer edge of the upper +surface of the maxillæ at base of rostrum. Vertebræ: C 7, D 10, L 12, C +19; total 48. The three anterior cervicals ankylosed, the rest free and +well developed. + +The only known species, _B. arnuxi_, attains the length of 30 feet, and +has hitherto only been met with in the seas around New Zealand. + +_Choneziphius._[149]—The rostral portions of crania from the Antwerp and +Suffolk Crags, on the evidence of which this genus has been established, +agree with those of _Mesoplodon_ in having the premaxillæ in contact with +the intervening bones throughout the length of their inner surfaces, and +also in showing only a very small portion of the vomer on the inferior +surface; they differ, however, in that the mesethmoid cartilage remains +unossified, whereby a fistular vacuity remains. In some species the +soldering of the inner surfaces of the premaxillæ is incomplete. The +interorbital region of the skull is flat; and there are two pits in the +nasal region, of which the right is the larger. + + +_Family_ SQUALODONTIDÆ. + +Numerous extinct forms, chiefly known by teeth and fragments of crania, +may be provisionally placed here, until more of their osteological +characters shall be brought to light. They differ from all existing +Cetaceans in having the teeth distinctly differentiated into groups, +as in the Archæoceti, the posterior molars being two-rooted. The +cranium has, however, none of the distinguishing characteristics of the +Zeuglodonts, but essentially resembles that of the Odontoceti, especially +in the position of the anterior nares and form of the nasal bones. + +_Squalodon._[150]—All the forms may be included in this genus, the +so-called _Rhizoprion_ not being distinct. Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, +simple teeth of the molar series (premolars?) ⁴⁄₄, two-rooted molars +⁷⁄₇ = ¹⁵⁄₁₅; total 60. The double-rooted molars differ from those of +_Zeuglodon_ in having the denticulations of the crown confined to the +posterior border, or at all events much less developed on the front +edge. Very little is known of the structure of these animals beyond the +skull and teeth, fragments of which have been found widely distributed +throughout the marine Miocene and early Pliocene formations of Europe, +especially in the Vienna basin, many parts of France, and the Antwerp and +Suffolk Crags. They have also been found in formations of corresponding +age in North America and South Australia. A few isolated teeth have been +met with in the cave-deposits of Italy, which, if contemporaneous with +the beds in which they occur, indicate the survival of the genus into the +Pleistocene period. + + +_Family_ PLATANISTIDÆ. + +Under this heading may be placed three very singular genera, which, +though differing considerably from each other, have several points in +common, and do not altogether come under the definition either of the +_Physeteridæ_ or the _Delphinidæ_, especially in the important character +of the mode of articulation of the ribs with the dorsal vertebræ, the +tubercular and capitular articulations, distinct at the commencement of +the series, gradually blending together, as they do in most ordinary +mammals. The cervical vertebræ are all free. The lachrymal bone is not +distinct from the jugal. The jaws are long and narrow, with numerous +teeth in both. The symphysis of the mandible exceeds half the length +of the whole ramus. Externally the head is divided from the body by a +slightly constricted neck. Pectoral limbs broad and truncated. Dorsal fin +small or obsolete. Fluviatile or estuarine in habits. There are three +distinct genera, which might almost be made the types of families, but it +is probably more convenient to keep them together, only regarding them as +representing three subfamilies. + +_Platanista._[151]—Teeth about ³⁰⁄₃₀ on each side, set near together, +rather large, cylindrical, and sharp-pointed in the young; in old animals +acquiring a large laterally compressed base, which in the posterior part +of the series becomes irregularly divided into roots. As the conical +enamel-covered crown wears away, the teeth of the young and old animals +have a totally different appearance. The rostrum and dentigerous portion +of the mandible are so narrow that the teeth of the two sides are almost +in contact. Maxillæ supporting very large, incurved, compressed bony +crests, which overarch the nares and base of the rostrum, and almost meet +in the middle line above. Orbits very small and eyes rudimentary, without +crystalline lens. External respiratory aperture longitudinal, linear. +Vertebræ: C 7, D 10, L 9, C 26; total: 52. A small cæcum. No pelvic +bones. Dorsal fin represented by a low ridge. + +[Illustration: FIG. 88.—_Platanista gangetica._ (From Anderson.)] + +One species, _P. gangetica_, entirely fluviatile, being extensively +distributed throughout nearly the whole of the river systems, not only of +the Ganges, but of the Brahmaputra and Indus, ascending as high as there +is water enough to swim in, but never passing out to sea. It is quite +blind, and feeds on small fish and crustaceans, groping for them with +its long snout in the muddy water at the bottom of the rivers. It attains +the length of 8 feet.[152] + +_Inia._[153]—Teeth variable, from 26 to 33 on either side of each jaw; +those at the posterior part with a distinct tubercle at the inner side +of the base of the crown. Vertebræ: C 7, D 13, L 3, C 18; total 41. +Transverse processes of lumbar vertebræ very broad. Sternum short and +broad, and consisting of a single segment only. Dorsal fin a mere ridge. +The long cylindrical rostrum externally furnished with scattered, stout, +and crisp hairs. One species only is known, _I. geoffroyensis_, about 7 +feet in length, inhabiting the upper Amazon and its tributary streams. + +_Pontoporia._[154]—Teeth 50 to 60 on either side of each jaw, with a +cingulum at the base of the crown. Jaws very long and slender. Vertebræ: +C 7, D 10, L 5, C 19; total 41. Transverse processes of the lumbar +vertebræ extremely broad. Sternum elongated, composed of two segments, +with four sternal ribs attached. Dorsal fin rather small, triangular, +pointed. External respiratory aperture transverse, crescentic. This genus +connects the last two forms with the true _Delphinidæ_. The only species, +_P. blainvillei_, is one of the smallest members of the whole order, not +exceeding 5 feet in length. It has only been met with at the mouth of the +Rio de la Plata, near Buenos Ayres, and there is at present no evidence +that it ascends into the fresh waters of the river. + +[Illustration: FIG. 89.—_Pontoporia blainvillei._ (From Burmeister.)] + +_Fossil forms._—Remains of a Cetacean from the Pleistocene of South +America were referred by Bravard to _Pontoporia_, but they have been +regarded by other writers as indicating a distinct genus, for which +the names _Palæopontoporia_ and _Pontistes_ have been proposed. The +Upper Tertiary European genera _Champsodelphis_ and _Schizodelphis_ +are generally referred to the present family. The former has wide +transverse processes to the lumbar vertebræ, as in _Inia_, while the +teeth also resemble those of that genus. In _Schizodelphis_ the form +of the rostrum presents a great resemblance to that of the Delphinoid +genus _Steno_, but the symphysis of the mandible is relatively longer. A +number of fossil Cetaceans from the Miocene of the United States, such +as _Priscodelphinus_, _Lophocetus_, _Ixacanthus_, _Rhabdosteus_, etc., +are referred by Professor E. D. Cope to this family. _Agabelus_, from the +same deposits, is an apparently allied, but toothless type. + + +_Family_ DELPHINIDÆ. + +Teeth usually numerous in both jaws. Pterygoid bones short, thin, each +involuted to form with a process of the palate bone the outer wall of +the post-palatine air-sinus. Symphysis of mandible short, or moderate, +never exceeding one-third of the length of the ramus. Lachrymal bone not +distinct from the jugal. The anterior facet on the periotic (Fig. 96) +for articulation with the tympanic deeply grooved; and the posterior +tympanic surface of the same bone comparatively narrow, with its ridge +for articulation with the free border of the tympanic ill-defined, and +situated close to one edge. Transverse processes of the dorsal vertebræ +gradually transferred from the arches to the bodies of the vertebræ +without any sudden break, and becoming posteriorly continuous serially +with the transverse processes of the lumbar vertebræ. Anterior ribs +attached to the transverse process by the tubercle, and to the body of +the vertebra by the head; the latter attachment lost in the posterior +ribs. Sternal ribs firmly ossified. External respiratory aperture +transverse, crescentic, with the horns of the crescent pointing forwards. + +A very large group, closely united in essential characters but +presenting great modifications in details. The different types are +mostly so connected by intermediate or osculant forms that there are +great difficulties in grouping them into natural subfamilies. Even the +formation of well-defined genera is by no means satisfactory in all +cases. They may, however, be divided, perhaps artificially, into two +groups. + +_Group A._—Head rounded, without distinct rostrum or beak. Rostrum of +skull about as long as cranial portion. + +_Monodon._[155]—Besides some irregular rudimentary teeth, the entire +dentition is reduced to a single pair of teeth which lie horizontally in +the maxilla, and in the female remain permanently concealed within the +alveolus so that this sex is practically toothless, while in the male +(see Fig. 90) the right tooth usually remains similarly concealed and +abortive, and the left is immensely developed, attaining a length equal +to more than half that of the entire animal, projecting horizontally from +the head in the form of a cylindrical, or slightly tapering, pointed +tusk, without enamel, and with the surface marked by spiral grooves +and ridges, running in a sinistral direction. (When, as occasionally +happens, both tusks are developed, the spiral grooves have the same +direction in each.) Pterygoids very small, not meeting in the middle +line, but approximating posteriorly. Vertebræ: C 7, D 11, L 6, C 26; +total 50. Cervical region comparatively long, and all the vertebræ +distinct, or with irregular unions towards the middle of the series, the +atlas and axis being usually free. Manus small, short, and broad; second +and third digits nearly equal, fourth slightly shorter. No dorsal fin. + +This genus is now represented only by the well-known Narwhal (_M. +monoceros_), in which the horn-like tusk of the male often grows to a +length of 7 or 8 feet. In very young animals several small additional +teeth, irregular in number and position, are present, but these usually +disappear soon after birth. + +The head is rather short and rounded; the fore limbs or paddles are small +and broad compared with those of most Dolphins; and (as in the Beluga) +the median dorsal fin, found in nearly all other members of the group, is +wanting or replaced by a low ridge. The general colour of the surface is +dark gray above and white below, but variously marbled and spotted with +different shades of gray. In the general contour of the body the Narwhal +resembles the White Whale or Beluga. + +[Illustration: FIG. 90.—Upper surface of the skull of male Narwhal +(_Monodon monoceros_), with the whole of both teeth exposed by removal of +the upper wall of their alveolar cavities.] + +The Narwhal is essentially an Arctic animal, frequenting the icy +circumpolar seas, and but rarely seen south of 65° N. lat. Three +instances have, however, been recorded of its occurrence on the +British coasts, one in the Firth of Forth in 1648, one near Boston in +Lincolnshire in 1800, while a third, which entangled itself among the +rocks in the Sound of Weesdale, Shetland, in September 1808, is described +by Fleming in the _Memoirs of the Wernerian Society_, vol. i. Like most +other Cetaceans, it is gregarious in its habits, being usually met with +in “schools” or herds of fifteen or twenty individuals. Its food appears +to be various species of cephalopods, small fishes, and crustaceans. +The purpose served in the animal’s economy by the wonderfully developed +asymmetrical tusk—or “horn,” as it is commonly but erroneously called—is +not known. As it is present only in the male sex, no function essential +to the well-being of the individual, such as the procuring of sustenance, +can be assigned to it, but it must be looked upon as belonging to the +same category of organs as the antlers of deer, and perhaps may be +applied to similar purposes. Very little is, however, known of the habits +of Narwhals. Scoresby describes them as “extremely playful, frequently +elevating their horns and crossing them with each other as in fencing.” +They have never been known to charge and pierce the bottom of ships with +their weapons, as the sword-fish often does. The name “Sea Unicorn,” +sometimes applied to the Narwhal, refers to the resemblance of its tusk +to the horn represented as projecting from the forehead of the fabled +unicorn. The ivory of which the tusk is composed is of very good quality, +but, owing to the central cavity, which extends the greater part of its +length, is only fitted for the manufacture of objects of small size. +The entire tusks are sometimes used for decorative purposes, and are of +considerable, though very fluctuating, commercial value. + +_Delphinapterus._[156]—This genus is closely allied to the last in +external form, as well as anatomical structure, differing mainly in +the very distinct character of the dentition. Teeth from ⁸⁄₈ to ¹⁰⁄₁₀, +occupying the anterior three-fourths of the rostrum and corresponding +portion of the mandible, rather small, conical, and pointed when unworn, +but usually becoming obliquely truncated, separated by intervals +considerably wider than the diameter of the tooth, and implanted +obliquely, the crowns inclining forwards, especially in the upper jaw. +Skull rather narrow and elongated, depressed. Premaxillæ convex in front +of the nares. Rostrum about equal in length to the cranial portion of the +skull, triangular, broad at the base, and gradually contracting towards +the apex, where it is somewhat curved downwards. Vertebræ: C 7, D 11, +L 9, C 23; total 50. Cervical vertebræ free. Manus broad, short, and +rounded, all the digits being tolerably well developed, except the first. +No dorsal fin, but a low ridge in its place. + +[Illustration: FIG. 91.—Beluga or White Whale (_Delphinapterus leucas_). +From a specimen taken in the river St. Lawrence, and exhibited in London, +1877.] + +One existing species, _D. leucas_ (Fig. 91), the Beluga or White Whale, +so called from its pure white colour, about 12 feet long, abundant in +the Arctic seas, and extending as far south on the American coast as the +river St. Lawrence, which it ascends for a considerable distance. On rare +occasions it has been seen on the coast of Scotland. + +Remains of a Cetacean from the Lower Pliocene of Tuscany have been +referred by Brandt to this genus under the name _D. brocchii_. + +In all the remaining genera of _Delphinidæ_ the cervical region of the +vertebral column is very short, and the first two, and usually more, of +the vertebræ are firmly united. + +_Phocæna._[157]—Teeth ²⁵⁄₂₅, small, occupying nearly the whole length +of the rostrum, with compressed, spade-shaped crowns, separated from +the root by a constricted neck (Fig. 92). Rostrum rather shorter than +the cranium proper, broad at the base and tapering towards the apex. +Premaxillæ raised into tuberosities in front of the nares. The frontal +bones forming a somewhat square, elevated protuberance in the middle line +of the skull behind the nares, rising altogether above the flattened +nasals. Pterygoids very small, and widely separated in the middle line. +Symphysis of mandible very short. Vertebræ: C 7, D 13, L 14, C 31; total +65 (subject to slight individual variations). First to sixth cervical +vertebræ, and sometimes the seventh also, coalesced. Manus of moderate +size, oval, slightly falcate; second and third digits nearly equal in +length; fourth and fifth well developed, but shorter. Dorsal fin near the +middle of the back, triangular; its height considerably less than the +length of the base; its anterior edge frequently furnished with one or +more rows of conical horny tubercles. + +[Illustration: FIG. 92.—Teeth of Porpoise. Twice natural size.] + +The common Porpoise (Fig. 93), _P. communis_, is the best known of +British Cetaceans. The word Porpoise (sometimes spelled Porpus and +Porpesse) is apparently derived from the French _porc_ and _poisson_, or +the Italian _porco_ and _pesce_, and thus corresponds with some of the +English vernacular appellations, “hog-fish,” “sea-hog,” “herring-hog,” +and the German _Meerschwein_, whence the usual modern French name of the +animal, _marsouin_. “Porpoise” is commonly used by sailors to designate +all the smaller Cetaceans, especially those numerous species which +naturalists call “Dolphins”; but in scientific language it is restricted +to the genus _Phocæna_ of Cuvier, of which the Porpoise of the British +seas, _Phocæna communis_, Cuvier (_Delphinus phocæna_, Linnæus), is the +type. + +The Common Porpoise, when full grown, attains a length of 5 feet or a +little more. The dimensions of an adult female specimen from the English +Channel were as follows:—length in straight line from nose to median +notch between the flukes of the tail, 62½ inches; from the nose to the +anterior edge of the dorsal fin, 29 inches; height of dorsal fin, 4½ +inches; length of base of dorsal fin, 8 inches; length of pectoral fin, +9¼ inches; breadth of pectoral fin, 3½ inches; breadth of tail flukes, +13 inches. The under jaw projects about half an inch beyond the upper +one. The aperture of the mouth is tolerably wide, and is bounded by +stiff immobile lips, and curves slightly upwards at the hinder end. The +eye is small, and the external ear represented by a minute aperture in +the skin, scarcely larger than would be made by the puncture of a pin, +situated about 2 inches behind the eye. The pectoral fins are of moderate +size, and slightly falcate. The upper parts are dark gray, or nearly +black, according to the light in which they are viewed, and the state +of moisture or otherwise of the skin; the under parts are pure white. +The line of demarcation between these colours is not distinct (washes or +splashes of gray encroaching upon the white on the sides), and varies +somewhat in different individuals. Usually it passes from the throat +(the anterior part of which, with the whole of the under jaw, is dark) +above the origin of the pectoral fin, along the middle of the flank, and +descends again to the middle line before reaching the tail. Both sides of +the pectoral and caudal fins are black. + +[Illustration: FIG. 93.—The Common Porpoise (_Phocæna communis_).] + +The Porpoise is sociable and gregarious in its habits, being usually +seen in small herds, and frequenting coasts, bays, and estuaries rather +than the open ocean. It is the commonest Cetacean in the seas around the +British Isles, and not unfrequently ascends the river Thames, having been +seen as high up as Richmond; it has also been observed in the Seine at +Neuilly, near Paris. It frequents the Scandinavian coasts, entering the +Baltic in the summer; and is found as far north as Baffin’s Bay, and as +far west as the coasts of the United States. Southward its range is more +limited than that of the Common Dolphin, as, though very common on the +Atlantic coasts of France, it rarely enters the Mediterranean. + +It feeds on fish, such as mackerel, pilchards, and herrings, of which +it devours large quantities, and, following the shoals, is often caught +by fishermen in the nets along with its prey. In former times it was a +common and esteemed article of food in England and in France, but is +now rarely if ever eaten, being commercially valuable when caught only +for the oil obtained from its blubber. Its skin is sometimes used for +leather and boot-thongs, but the so-called “porpoise hides” are generally +obtained from the Beluga. + +A closely similar if not identical species from the American coast of the +North Pacific has been described under the name of _Phocæna vomerina_, +and another from the mouth of the Rio de la Plata as _P. spinipennis_. + +[Illustration: FIG. 94.—Diagrammatic section of the stomach of the +Porpoise. _a_, Œsophagus; _b_, left, or cardiac, compartment; _c_, middle +compartment; _d_ and _e_, the two divisions of the right, or pyloric, +compartment; _f_, pylorus; _g_, duodenum, dilated at its commencement; +_h_, biliary duct.] + +The stomach of the Porpoise (Fig. 94) may be taken as a typical +example of this organ in the Cetacea. The first and by far the largest +compartment (_b_) may be regarded as a kind of crop, or dilatation of +the large œsophagus (_a_). It is lined by a thick white epithelium, +which ceases abruptly at the entrance into the next cavity. It +corresponds to the cardiac compartment of the stomach in the Ungulates +and certain Rodents; but, although its walls do not appear to contain +peptic glands, its contents undergo partial digestion—probably caused +by the regurgitation into it of the secretions of the second, or true +digestive compartment (_c_). This, which is much smaller than the first, +has very thick walls, the mucous membrane being filled with numerous +tubular glands. The surface of this membrane is smooth and soft, being +thrown into numerous folds, which in this genus are arranged in a very +peculiar and characteristic manner, so as to form a series of prominent +longitudinal ridges, each of which sends off short lateral ridges at +right angles to itself, which interdigitate with those proceeding from +the next longitudinal ridge. The remainder of the stomach (_d_ to _f_) +may be compared to the pyloric antrum of the stomach of ordinary mammals. +It is elongated, cylindrical, and intestiniform, with a smooth lining +membrane, sharply bent upon itself, and terminating in a very small +circular pyloric aperture (_f_). In the Porpoise the commencement of +this cavity is constricted off from the remainder, so as to form a small +globular sac. In most Dolphins (as _Tursiops_, _Globicephalus_, and +_Grampus_) there are two such small sacs of very similar size and form, +communicating by circular pylorus-like apertures; and in _Hyperoödon_ the +whole compartment is divided by a series of constrictions into as many as +seven separate cavities, which have been regarded as distinct stomachs. +Immediately beyond the pylorus the duodenum has a globular dilatation, as +in the camels and some other Ungulates, into the lower end of which the +biliary duct (_h_) enters. + +An allied species, differing mainly in the absence of dorsal fin, and +in the teeth (with the same form of crown) being fewer in number and of +larger size, called _Delphinus phacænoides_ by Cuvier, _D. melas_ by +Schlegel, forms the type of Gray’s genus _Neomeris_.[158] It is rather +smaller than the Common Porpoise, and almost entirely black in colour. +Common off the coast of Bombay, it has been met with in other parts of +the Indian Ocean, and near Japan. The British Museum recently received +a specimen taken in the Chinese river Yang-tse-kiang nearly a thousand +miles from the sea, which only differs from others from India in wanting +a patch of small horny tubercles on the back. As such tubercles are +present or absent in otherwise similar individuals of _P. communis_, +it is doubtful whether they can be regarded as constituting a specific +character. + +_Cephalorhynchus._[159]—Rostrum as long and sometimes slightly longer +than the cranial portion of the skull. Pterygoids widely separated from +one another. Teeth small (less than 3 mm. in diameter), ²⁵⁄₂₅ to ³⁰⁄₃₀. +Vertebræ: C 7, D 13, L 15, C 30; total 65. Dorsal fin low, obtusely +triangular or rounded. Pectoral fins rather small, narrow, and ovate. +Typified by _C. heavisidei_, from the southern seas. _C. eutropia_ is +a very distinct form from the same seas, known only by the skull, and +referred provisionally to this genus. + +_Orcella._[160]—Teeth ¹²⁄₁₂ to ¹⁴⁄₁₄, small, conical, pointed, rather +closely set, and occupying nearly the whole length of the rostrum. Skull +subglobular, high. Rostrum nearly equal in length to the cranial portion +of the skull, tapering. Pterygoids widely separated from one another. +Manus of moderate size, not elongated, but somewhat pointed. All the +bones of the digits broader than long, except the proximal phalanges of +the index and third fingers. Dorsal fin rather small, placed behind the +middle of the body. Two species, both of small size—_O. brevirostris_, +from the Bay of Bengal, and _O. fluminalis_, from the Irawadi river, from +300 to 900 miles from the sea. Our present knowledge of the anatomy, +geographical distribution, and habits of these interesting Cetaceans is +almost entirely due to the researches of Dr. J. Anderson.[161] + +_Orca._[162]—Teeth about ¹²⁄₁₂, occupying nearly the whole length of the +rostrum, very large and stout, with conical recurved crowns, and large +roots, expanded laterally and flattened, or rather hollowed, on the +anterior and posterior surfaces. Rostrum about equal in length to the +cranial part of the skull, broad and flattened above, rounded in front; +premaxillæ broad and rather concave in front of the nares, contracted +at the middle of the rostrum, and expanding again towards the apex. +Pterygoids of normal form, but not quite meeting in the middle line. +Vertebræ: C 7, D 11-12, L 10, C 23; total 51 or 52. Bodies of the first +and second and sometimes the third cervical vertebræ united; the rest +free. Pectoral fin very large, ovate, nearly as broad as long. All the +phalanges and metacarpals broader than long. General form of body robust. +Dorsal fin near the middle of the back, very high and pointed. Anterior +part of the head broad and depressed. + +The animals composing this genus are met with in almost all seas from +Greenland to Tasmania, but the number of species is still uncertain, +and possibly they may be all reduced to one. They are readily known, +when swimming in the water, by the high, erect, falcate dorsal fin, +whence their common German name of _Schwertfisch_ (Sword-fish). By +English sailors they are generally known as “Grampuses” or “Killers.” +They are distinguished from all their allies by their great strength and +ferocity, being the only Cetaceans which habitually prey on warm-blooded +animals, for, though fish form part of their food, they also attack +and devour Seals, and various species of their own order, not only the +smaller Porpoises and Dolphins, but even full-sized Whales, which last +they combine in packs to hunt down and destroy, as Wolves do the larger +Ruminants. + +[Illustration: FIG. 95.—The Killer Whale, or Grampus (_Orca gladiator_). +From Hunter.] + +_Orca citoniensis_, of the Italian Pliocene, was of smaller size than +the existing Killer. Teeth and periotic bones from the Suffolk Crag not +improbably belong to the same species. + +_Pseudorca._[163]—Teeth about ¹⁰⁄₁₀. Cranial and dental characters +generally like those of _Orca_, except that the roots of the teeth are +cylindrical. Vertebræ: C 7, D 10, L 9, C 24; total 50. First to sixth +or seventh cervical vertebræ united. Bodies of the lumbar vertebræ +distinguished from those of the preceding genera by being more elongated, +the length being to the width as 3 to 2. Pectoral fin of moderate size, +narrow, and pointed. Dorsal fin situated near the middle of the back, +of moderate size, falcate. Head in front of the blowhole high, and +compressed anteriorly, the snout truncated. + +This genus was first known by the discovery of a skull in a subfossil +state in a fen in Lincolnshire, named by Sir R. Owen _Phocæna +crassidens_. Animals of apparently the same species were afterwards +met with in small herds on the Danish coast, and fully described by +Reinhardt. Others subsequently received from Tasmania were supposed +at first to indicate a different species, but comparison of a larger +series of specimens from these extremely distant localities fails to +establish any characteristic difference, and indicates an immense range +of distribution for a species apparently so rare. The length of this +Cetacean is about 14 feet, and its colour entirely black. + +_Globicephalus._[164]—Teeth ⁸⁻¹²⁄₈₋₁₂, confined to the anterior half +of the rostrum and corresponding part of the mandible, small, conical, +curved, sharp-pointed when unworn, sometimes deciduous in old age. Skull +broad and depressed. Rostrum and cranial portion about equal in length. +Upper surface of rostrum broad and flat. Premaxillæ strongly concave +in front of the nares, as wide at the middle of the rostrum as at the +base, or wider, and very nearly or completely concealing the maxillæ in +the anterior half of this region. Pterygoids of normal form, meeting, +or very nearly so, in the middle line. Vertebræ: C 7, D 11, L 12-14, +C 28-29; total 58 or 59. Bodies of the anterior five or six cervical +vertebræ united. Length of the bodies of the lumbar and anterior caudal +vertebræ about equal to their width. Pectoral limb very long and narrow, +the second digit the longest, and having as many as 12 or 13 phalanges, +the third shorter (with 9 phalanges), the first, fourth, and fifth very +short. Fore part of the head very round, in consequence of the great +development of a cushion of fat, placed on the rostrum of the skull in +front of the blowhole. Dorsal fin low and triangular, the length of its +base considerably exceeding its vertical height. + +The type of this well-marked genus is _G. melas_, the Pilot Whale, Ca’ing +Whale, or Grindhval of the Faroe islanders, which attains the length of +20 feet, and is of nearly uniform black colour, except the middle of the +under surface, which is lighter. These animals are extremely gregarious, +and, unlike the Killers, are mild and inoffensive in disposition, feeding +principally on cephalopods. Their eminently sociable character constantly +leads to their destruction, since when attacked they instinctively rush +together and blindly follow the leaders of the herd. When they are seen +in the neighbourhood of land, the fishermen endeavour to get to seaward +of them in their boats, and with shouting and firing of guns to drive +them into a bay or fjord, pursuing them until they run themselves on +shore in their alarm. In this way many hundreds at a time are frequently +driven ashore and killed, when a herd enters one of the bays or fjords of +the Faroe Islands or north of Scotland. Animals of this well-marked genus +are found in nearly all seas, and their specific distinctions are not yet +made out. Specimens from the Australian coasts, where they are generally +called “Black-fish,” are quite indistinguishable, either by external or +osteological characters, from those of the North Atlantic. + +[Illustration: FIG. 96.—The left periotic bone of _Globicephalus +uncidens_; from the Suffolk Crag. Natural size. The grooved surface on +the right is the anterior facet for articulation with the tympanic; the +posterior tympanic articulation being on the opposite side of the figure. +(From the _Cat. Foss. Mamm. Brit. Mus._ pt. v.)] + +Teeth, periotic (Fig. 96) and tympanic bones from the Suffolk Crag, +described as _G. uncidens_, indicate a form apparently closely allied to +the existing species. The periotic is figured in order to illustrate the +distinctive characters of that bone in the _Delphinidæ_. + +_Grampus._[165]—Teeth none in the upper jaw; in the mandible few (3 to +7 on each side), and confined to the region of the symphysis. Vertebræ: +C 7, D 12, L 19, C 30; total 68. General external characters much as in +_Globicephalus_, but the fore part of the head less rounded, and the +pectoral fin less elongated. + +But one species, _G. griseus_, is certainly known, about 13 feet long, +and remarkable for its great variability of colour. It has been found, +though rarely, in the North Atlantic and Mediterranean. A skull from the +Cape of Good Hope, which differs slightly from that of the above, has +been described under the name of _G. richardsoni_. + +_Feresia._[166]—This genus, known at present only by two skulls, may be +provisionally placed here. These appear to indicate a form connecting +_Globicephalus_, _Grampus_, and _Lagenorhynchus_. From the latter they +differ chiefly in the smaller number (about ¹²⁄₁₂) and much larger size +(6-7 mm. in diameter at base of crown) of the teeth. + +_Lagenorhynchus._[167]—Rostrum scarcely exceeding the length of the +cranium, broad at the base and gradually tapering towards the apex, +depressed. Pterygoids normal, meeting in the middle line. Teeth small +(not exceeding 4 mm. in diameter), ²³⁄₂₃ to ³³⁄₃₃. Vertebræ very +numerous, 80 to 90. Spines and transverse processes of the lumbar +vertebræ very long and slender; centra short. Externally, head with a +short but not very distinct beak. Two species, _L. albirostris_ and _L. +acutus_, are occasionally captured on the British coasts. Other species +occur elsewhere. + +_Group B._—Head with distinctly elongated rostrum, or beak, generally +marked off from the prenarial adipose elevation by a V-shaped groove. +Rostrum of skull considerably longer than the cranial portion. Atlas and +axis firmly united; all the other cervical vertebræ free. + +If we add to it the above-mentioned genus, _Lagenorhynchus_, this group +will include all the true Dolphins, Bottle-noses, or, as they are more +commonly called by seafaring people, “Porpoises,” which are found in +considerable abundance in all seas, some species being habitually +inhabitants of large rivers, as the Amazon. They are all among the +smaller members of the order, none exceeding 10 feet in length. Their +food is chiefly fish, for the capture of which their long narrow +beaks, armed with numerous sharp-pointed teeth, are well adapted, but +some appear also to devour crustaceans and molluscs. They are mostly +gregarious, and the agility and grace of their movements in the water +are constant themes of admiration to the spectators of the scene when a +“school of Porpoises” is observed playing round the bows of a vessel at +sea. + +_Delphinus._[168]—Teeth very numerous in both jaws, ⁴⁰⁄₄₀ to ⁶⁰⁄₆₀, +occupying nearly the whole length of the rostrum, small, close-set, +conical, pointed, slightly curved. Rostrum elongated, usually about +double the length of the cranial portion of the skull. Pterygoids of +normal form, meeting in the middle line throughout their length. Palate +with deep lateral grooves. Vertebræ 73 to 75. Pectoral fin of moderate +size, narrow, pointed, somewhat falcate. Second and third digits well +developed; the rest rudimental. + +The type of the genus is the Common Dolphin of the Mediterranean (_D. +delphis_, Fig. 97), also found in the Atlantic, and of which a closely +allied if not identical form is met with in the Australian seas (_D. +forsteri_) and in the North Pacific (_D. bairdi_). Other species are _D. +janira_, _D. major_, etc. + +[Illustration: FIG. 97.—The Common Dolphin (_Delphinus delphis_). From +Reinhardt.] + +_Tursiops._[169]—Rostrum tapering moderately from base to apex; palate +not grooved; symphysis of mandible short; other cranial characters as in +_Delphinus_. Teeth ²¹⁄₂₁ to ²⁵⁄₂₅, stout (6 to 7 mm. in antero-posterior +diameter). Vertebræ: C 7, D 13, L 17, C 27; total 64. Limbs as in +_Delphinus_. Represented by the widely distributed _T. tursio_; _T. +catalania_ being a second form. Fossil remains of this genus from the +Italian Pliocene have been recently described. + +_Prodelphinus._[170]—Rostrum somewhat variable; mandibular symphysis +short (less than one-fifth the length of the ramus); other cranial +characters as in the preceding genus. Teeth ³⁰⁄₃₀ to ⁵⁰⁄₅₀, small, not +exceeding 3 mm. in diameter. Vertebræ 73 to 78. Limbs as in _Delphinus_. +Four leading types of this genus are recognised (all of which have +numerous synonyms) viz. _P. obscurus_, _P. euphrosyne_, _P. doris_, and +_P. longirostris_. + +Péron’s Dolphin (_Delphinus leucorhamphus_, Péron, or _Leucorhamphus +peroni_, Lilljeborg) resembles some forms of _Prodelphinus_ in its +cranial characters; but having no dorsal fin, it has been separated +generically by some writers. It is not improbable that _Delphinus +borealis_, Peale, from the North Pacific, in which there is likewise no +dorsal fin, may be an allied form. + +_Steno._[171]—Rostrum long, narrow, and compressed, very distinct from +the cranium; mandibular symphysis as long as, or longer than one-fourth +the length of the ramus; other cranial characters as in the preceding +genus. Teeth ²¹⁄₂₁ to ²⁵⁄₂₅, of comparatively large size (5-6 mm. in +diameter); surface of their crowns finely grooved. Vertebræ: C 7, D 12, L +15, C 32; total 66. Represented by _S. rostratus_, from which the forms +which have received other names are probably not specifically separable. + +_Sotalia._[172]—Pterygoids narrow, not meeting in the middle line, and +in their inner borders diverging posteriorly, instead of being parallel +as in the preceding genera; other cranial characters much as in _Steno_. +Teeth tolerably large (4-5 mm. in diameter), ³⁰⁄₃₀ to ³⁵⁄₃₅, with smooth +enamelled surface. Vertebræ: C 7, D 12, L 10-14, C 22; total 51-55. +Pectoral fin broad at base, the breadth being caused by the considerable +development and position of the two outer digits. Six species are +provisionally recognised as distinct, including the Chinese White Dolphin +(_S. sinensis_) and _S. pallidus_ from the river Amazon. + + _Bibliography of Cetacea._—D. F. Eschricht, _Untersuchungen + über die Nordischen Wallthiere_, 1849, contains a copious + bibliography of the group up to the date of publication. + Since that time numerous monographs on special families and + genera have been published, and a large illustrated general + work, _Ostéographie des Cétacés_, by P. J. Van Beneden and P. + Gervais, 1869-80. Besides those already referred to in the + footnotes, the following may be mentioned; viz. J. F. Brandt, + “Untersuchungen über die Fossilen und Subfossilen Cetaceen + Europa’s,” in _Mém. de l’Acad. Imp. de St. Pétersbourg_, 7ⁱᵉᵐᵉ + sér. vol. xx. 1873; C. M. Scammon, _Marine Mammals of the N. W. + Coast of North America_, 1874; W. H. Flower, “On the characters + and Divisions of the Families of the _Delphinidæ_,” _Proc. + Zool. Soc._ 1883, p. 466, and _List of the Specimens of Cetacea + in the British Museum_, 1885; F. W. True, “Review of the Family + Delphinidæ,” _Bull. U.S. Nat. Museum_, No. 36, 1889; P. J. Van + Beneden, _Histoire Naturelle des Cétacés des Mers d’Europe_, + 1889. + + For fossil forms, in addition to the works of Van Beneden, + Gervais, and Brandt, already cited, the reader may refer to + various memoirs published by the former writer in the _Bull. + Ac. R. Belgique_ and _Ann. Mus. R. Hist. Nat. Belg._ See also + R. Lydekker, “The Cetacea of the Suffolk Crag,” _Quart. Journ. + Geol. Soc._ vol. xlii. p. 7 (1887), and _Catalogue of the + Fossil Mammalia in the British Museum_, pt. v. (1887). + + + + +CHAPTER IX + +THE ORDER UNGULATA + + +Under this term may be included provisionally a large and rather +heterogeneous group of mammals, the existing members of which form +the Pecora and Belluæ of Linnæus, the Ruminantia and Pachydermata of +Cuvier. A few years ago it was found convenient to restrict the order +to a well-marked and distinctly circumscribed group, comprising the two +sections known as Perissodactyla and Artiodactyla, and to leave out +such isolated forms as the Elephant and Hyrax; but the discovery of a +vast number of extinct species, which could not be brought under the +definition of either perissodactyle or artiodactyle Ungulates, and yet +are evidently allied to both, and to a certain extent bridge over the +interval between these and the isolated groups just mentioned, makes it +necessary either to introduce a number of new and ill-defined ordinal +divisions, or to widen the scope of the original order so as to embrace +them all. + +The existing forms are all animals eminently adapted for a terrestrial +life, and in the main for a vegetable diet. Though a few are more or +less omnivorous, and may under some circumstances kill living creatures +smaller and weaker than themselves for food, none are distinctly +and habitually predaceous. Their teeth are markedly heterodont and +diphyodont,—the milk set being well developed and not completely changed +until the animal attains its full stature. The molars have broad crowns +with tuberculated or ridged surfaces. There are no clavicles.[173] Their +toes are provided with blunt, broad nails, or in the majority of cases +with hoofs, more or less enclosing the ungual phalanges. The scaphoid +and lunar bones of the carpus are always distinct. The humerus has no +entepicondylar foramen. The number of digits varies from five to one; and +the radius and ulna may be united together. + +The more generalised of the fossil forms do not conform in all +respects to the above-mentioned characters; clavicles being present in +_Typotherium_, and perhaps in some of the Condylarthra, while in the +latter group the humerus may have an entepicondylar foramen, and thus +approximate to the corresponding bone of the Carnivora. Wide as is the +gap between existing Carnivores and Ungulates, there are indeed more or +less strongly marked evidences of affinity between the earlier members of +the two orders, as will be again noticed under the head of the suborder +Condylarthra. A departure from the normal type of foot-structure is +exhibited by the extinct _Macrotherium_, provisionally included in the +Perissodactyla, where the digits terminated in long and curved claws. + +As a general rule, the cheek-teeth have distinct roots, and in those of +the existing suborders a gradual increase in the height of the crowns +of these teeth may be noticed in passing from the more generalised +to the more specialised types. Those teeth in which the crowns are +low, and their whole structure visible from the grinding surface, are +termed _brachydont_ (Fig. 122); while those with higher crowns, in +which the bases of the infoldings of enamel are invisible from the +grinding surface, are known as _hypsodont_ (Fig. 123). Again, when the +tubercles on the crowns of the molars are more or less cone-like in form +the tooth is said to be _bunodont_; but when they are expanded in an +antero-posterior direction and curved into a crescent shape the tooth is +described as _selenodont_. + +[Illustration: FIG. 98.—Right fore foot of Indian Elephant. × ⅛. U, ulna; +R, radius; _c_, cuneiform; _l_, lunar; _sc_, scaphoid; _u_, unciform; +_m_, magnum; _td_, trapezoid; _tm_, trapezium; I to V, first to fifth +digit.] + +The whole order may be divided into the Ungulata Vera, containing the +suborders Perissodactyla and Artiodactyla, and a somewhat heterogeneous +assemblage of animals which may be called Subungulata or Ungulata +Polydactyla. Cope has pointed out a character in the structure of the +carpus by which the latter are differentiated from the former. Thus in +all the Subungulata the bones of the proximal and distal row retain the +primitive or more typical relation to each other (see Fig. 98); the os +magnum of the second row articulating mainly with the lunar of the +first, or with the cuneiform, but not with the scaphoid. But in the group +to which the vast majority of modern Ungulates belong the second or +distal row has been shifted altogether towards the inner side of the limb +(see Fig. 99), so that the magnum is brought considerably into relation +with the scaphoid, and is entirely removed from the cuneiform, as in the +great majority of existing mammals. + +It will be on the whole more convenient to commence our survey of the +members of this suborder with the more specialised group of the Ungulata +Vera, in which the Artiodactyla will be taken first. + + +UNGULATA VERA.[174] + +In the typical Ungulata the feet are never plantigrade, and the +functional toes do not exceed four—the inner digit being suppressed, +at all events in all forms which have existed since the Upper Eocene +period.[175] The os magnum of the carpus articulates freely with the +scaphoid. The allantois is largely developed, and the placenta, so far +as is known, is non-deciduate; the chorionic villi being either evenly +diffused or collected in groups or cotyledons (in Pecora). The testes +descend into a scrotum. There is never an os penis. The uterus is +bicornuate. The mammæ are usually few and inguinal, or may be numerous +and abdominal (as in Suina), but are never solely pectoral. The cerebral +hemispheres in existing Ungulates are well convoluted. + +The group is now, and has been throughout almost the whole of the +Tertiary period, composed of two perfectly distinct sections, differing +from each other, not only in the obvious characters of the structure +of the limbs, but in so many other parts of their organisation that +they must be considered as of the rank at least of suborders. The +characters of these divisions, first indicated by Cuvier, were thoroughly +established by Owen, by whom the names whereby they are now generally +known were proposed. + + +_Suborder_ ARTIODACTYLA. + +This is a well-defined group, traceable from the Eocene period, though +then apparently by no means so numerous as the Perissodactyles. Some of +its types, as that represented in the existing Swine, have retained to +the present time much of the primitive character of the group; but others +have been gradually becoming more specialised and perfected in structure, +and its latest modification, the Cavicorn Ruminants or _Bovidæ_ +(Antelopes, Sheep, and Oxen), are now the dominating members of the great +Ungulate order, widespread in geographical range, rich in generic and +specific variation, and numerous in individuals—forming in all these +respects a great contrast to such decadent types as those represented by +the Tapirs and Rhinoceroses. + +[Illustration: FIG. 99.—Bones of right fore foot of existing +Artiodactyles. A, Pig (_Sus scrofa_), × ⅓; B, Red Deer (_Cervus +elaphus_), × ⅐; C, Camel (_Camelus bactrianus_), × ⅛. _U_, Ulna; _R_, +radius; _c_, cuneiform; _l_, lunar; _s_, scaphoid; _u_, unciform; _m_, +magnum; _td_, trapezoid; _tm_, trapezium. From Flower’s _Osteology of +Mammalia_.] + +The principal anatomical characters by which the Artiodactyles are +distinguished from the Perissodactyles are as follows. The premolar and +molar teeth usually not alike, the former being single and the latter +two-lobed. The last lower molar of both first and second dentition +almost invariably three-lobed; and the first tooth of the upper cheek +series always without a milk-predecessor. Nasal bones not expanded +posteriorly. No alisphenoid canal. Dorsal and lumbar vertebræ together +always nineteen, though the former may vary from twelve to fifteen. Femur +without third trochanter. Third and fourth digits of both feet almost +equally developed, and their ungual phalanges flattened on their inner or +contiguous surfaces, so that each is not symmetrical in itself, but when +the two are placed together they form a figure symmetrically disposed to +a line drawn between them. Or, in other words, the axis or median line +of the whole foot is a line drawn between the third and fourth digits, +while in the Perissodactyles it is a line drawn down the centre of the +third digit. Distal articular surface of the astragalus divided into two +nearly equal facets, one for the navicular and the other for the cuboid +bone. The calcaneum with an articular facet for the lower end of the +fibula. Stomach almost always more or less complex. Colon convoluted. +Cæcum small. Placenta diffused or cotyledonary. Mammæ few and inguinal, +or numerous and abdominal. + +In treating of many sections of mammals, it is only from the existing +species that our characters and classification can be derived, and to +these chiefly our observations upon the group must be directed, many of +the extinct forms being so little known that they can only be referred +to incidentally. With the Ungulata, however, it is quite otherwise. The +history of the Artiodactyla throughout the Tertiary period is now well +known, and throws great light upon the position and relations of the +existing groups. + +The principal modifications which have taken place in the type from +its earliest known and most generalised manifestation have been the +following:— + +1. As regards the teeth. Assumption by the grinding surfaces of the molar +teeth either of a bunodont or of a selenodont form. Modification of the +latter from a brachydont to a hypsodont type. Loss of upper incisors. +Development of canines into projecting tusks. Loss of anterior premolars. + +2. As regards the limbs. Reduction of the ulna from a complete and +distinct bone to a comparatively rudimentary state, in which it coalesces +more or less firmly with the radius. Reduction of the fibula till nothing +but its lower extremity remains. Reduction and final loss of external +pair of digits (second and fifth), with coalescence of the metapodial +bones of the two middle digits. Union of the navicular and cuboid, and +sometimes the ectocuneiform, bones of the tarsus. + +3. Change of form of the odontoid process of the axis vertebra from a +cone to a hollow half-cylinder. + +4. Development of horns or antlers on the frontal bones, and gradual +complication of form of antlers. + +5. By inference only, increasing complication of stomach with ruminating +function superadded. Modification of placenta from simple diffused to +cotyledonary form. + +The primitive Artiodactyles, with the typical number (44) of incisor, +canine, and molar teeth, brachydont molars, conical odontoid process, +four distinct toes on each foot, with metapodium and all carpal bones +distinct, no frontal appendages, and (in all probability) simple stomach +and diffused placenta, were separated at a very early period into +Bunodonts and Selenodonts, although there is evidence of intermediate +forms showing a complete transition from the one modification to +the other. These and other fossil forms so completely connect the +four groups—Suina, Tylopoda, Tragulina, and Pecora—into which the +existing members of the suborder have become divided, that in a general +classification embracing both living and extinct forms these divisions +cannot be maintained. In the present work, however, it will be convenient +to retain them, mention being made of some of the chief annectant forms +in separate sections. + + +SUINA. + +The existing members of this group are characterised by their bunodont +molars, and the absence of a complete fusion of the third and fourth +metapodials to form a “cannon-bone.” The full Eutherian dentition is very +frequently present. + +Remains of very generalised swine-like animals have been abundantly +found in Tertiary formations both in America and Europe. In the former +continent they never (so far as present evidence indicates) underwent any +great diversity of modification, but gradually dwindled away and almost +died out, being only represented in the actual fauna by the two closely +allied species of Peccary, among the smallest and most insignificant +members of the group, which have existed almost unchanged since the +Miocene age at least, if the evidence of teeth alone can be trusted. In +the Old World, on the other hand, the swine have played a more important +part in recent times, having become widely distributed, and throwing +off some curiously specialised forms. At the present time, though not +very numerous in species, they range through the greater part of the Old +World, except within or near the Arctic Circle, although, in common with +all the other members of the great Ungulate order, they were completely +absent from the whole of the Australian region, until introduced by man +in very recent times. + +The existing swine-like animals may be divided naturally into three +families:—I. _Hippopotamidæ_; II. _Suidæ_, or true Pigs; III. +_Dicotylidæ_, or Peccaries.[176] + + +_Family_ HIPPOPOTAMIDÆ. + +[Illustration: FIG. 100.—Grinding surface of a worn molar of +_Hippopotamus amphibius_. (From Owen.)] + +Muzzle very broad and rounded. Feet short and broad, having four +subequal toes, with short rounded hoofs, all reaching the ground in +walking. Incisors not rooted, but continuously growing; those of the +upper jaw curved and directed downwards; those of the lower straight and +procumbent. Canines very large, curved, continuously growing; those of +the upper jaw directed downwards. Stomach complex. No cæcum. + +_Hippopotamus._[177]—This genus may be taken to include all the known +members of the family; it appears to have been always confined to the +Old World. The dentition may be expressed by the formula _i_ ²⁻³⁄₁₋₃, +_c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃. The crowns of the molars (Fig. 100) when worn +present trefoil-shaped surfaces of dentine; and those of the premolars +are sharp. The facial portion of the skull is much elongated, the orbits +are tubular and very prominent, and the mandible has a large rounded +descending flange at its angle. The ears are small, the tail is short, +and the legs are likewise so short that the belly is raised but a little +distance above the ground. The brain is not richly convoluted, and +differs very considerably from that of the Pigs, approximating in some +respects to that of the Camel and Giraffe, but on the whole standing +very much by itself. The stomach of the common species is of enormous +dimensions, having an axial length of 11 feet, and measuring upwards +of 15 feet along the greater curvature. Its axis is longitudinal, the +pylorus being situated almost in the pelvis, and it is divided into three +distinct compartments, of which the third is cylindrical. The liver of +the adult is of extremely simple form, elongated transversely, and narrow +from above downwards. With the exception of a few tufts of hair on the +lips, on the sides of the head and neck, and at the extremity of the +short compressed tail, the skin of the hippopotamus, some portions of +which are two inches in thickness, is entirely destitute of covering. + +[Illustration: FIG. 101.—The Hippopotamus (_Hippopotamus amphibius_).] + +The common Hippopotamus (_H. amphibius_), widely distributed in the +rivers and lakes of the African continent, is a huge bulky animal, +characterised by having only two incisors on either side of each jaw; the +central lower pair being very much larger than the outer ones. A male +from the Upper Nile which lived for nearly thirty years in the gardens of +the Zoological Society of London measured 12 feet along the back from the +nose to the root of the tail. + +The Hippopotamus lives in herds of from twenty to forty individuals on +the banks and in the beds of rivers, in the neighbourhood of which it +finds its food. This consists chiefly of grass and aquatic plants, of +which it consumes enormous quantities, the stomach being capable of +containing from 5 to 6 bushels. These animals feed principally by night, +remaining in the water during the day, although in districts where +they are undisturbed by man they are less exclusively aquatic. In such +regions they put their heads boldly out of the water to blow, but when +rendered suspicious by persecution, they become exceedingly cautious, +only exposing their eyes and nostrils above the water, and even this they +prefer doing amid the shelter of water plants. In spite of their enormous +size and uncouth form, they are expert swimmers and divers, and can +remain under the water from five to eight minutes. They are said to walk +with considerable rapidity on the bottoms of rivers, beneath at least a +foot of water. At nightfall they come on land to feed; and when, as often +happens on the banks of the Nile, they reach cultivated ground, they do +immense damage to growing crops, destroying by their ponderous tread even +more than they devour. + +A much smaller species, known as the Pigmy Hippopotamus (_H. +liberiensis_), inhabits some of the rivers of Western Africa, and is +characterised by having only a single pair of lower incisors. Mainly on +this account, it has been proposed to regard this species as representing +a distinct genus, under the name of _Chœropsis_; but since it agrees +so essentially in other characters with the common form, and sometimes +has two incisors on one side of the lower jaw, it appears preferable +to include it in the type genus. The greater relative size of the +brain-cavity as compared with the facial portion of the skull renders, +indeed, the contour of the skull decidedly different from that of _H. +amphibius_, but this is a feature generally found in young individuals of +larger species, and also in the adults of allied smaller forms. + +Both the existing species are now exclusively confined to Africa, but +in the Pleistocene and Pliocene periods the genus was widely spread +over the Old World. Thus in the Upper Pliocene of the Continent and +the Pleistocene of England we meet with remains of a very large +fossil Hippopotamus which cannot be specifically distinguished from +_H. amphibius_. In the Pleistocene and Pliocene of India there are +two species having three pairs of incisors in both jaws. Of these _H. +palæindicus_ has the second pair in the lower jaw very minute, and +evidently just about to disappear; from which we learn that it is this +pair which is missing in _H. amphibius_. In the still more generalised +_H. sivalensis_ the three incisors in the lower jaw are of equal size. +Hexaprotodont species also occur in the Upper Tertiaries of Burma and +Algeria. Small tetraprotodont species (_H. pentlandi_ and _H. minutus_) +have left their remains in enormous quantities in the caves and fissures +of Sicily and Malta. + + +_Family_ SUIDÆ. + +An elongated mobile snout, with an expanded, truncated, nearly naked, +flat, oval terminal surface in which the nostrils are placed. Feet +narrow; four completely developed toes on each. Hoofs of the two middle +toes with their contiguous surfaces flattened. The outer (second and +fifth) digits of existing forms not reaching to the ground in the +ordinary walking position. Teeth variable in number, owing to the +suppression in some forms of an upper incisor and one or more premolars. +Incisors rooted. Upper canines curving more or less outwards or upwards. +Stomach simple, except for a more or less developed pouch near the +cardiac orifice. A cæcum. Colon spirally coiled. Confined to the Old +World. + +The mandible has no descending flange at the angle. The crowns of the +molars do not wear into such distinct trefoils as in the Hippopotamus, +and are oblong in shape. The last molar of both the upper and lower jaw +(Fig. 102) has an additional hinder lobe or talon, varying in size in the +different species. The upper premolars are simpler than the true molars. + +[Illustration: FIG. 102.—Grinding surface of a worn third right lower +molar of the Wild Boar (_Sus scrofa_). After Owen.] + +_Sus._[178]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃; total 44. +Upper incisors diminishing rapidly in size from the first to the third. +Lower incisors long, narrow, closely approximated, and almost horizontal +in position, their apices inclining towards the middle line; the second +slightly larger than the first, the third much smaller. Canines strongly +developed and with persistent roots and partial enamel-covering, those +of the upper jaw not having the usual downward direction, but curving +strongly outwards, upwards, and finally inwards, while those of the lower +jaw are directed upwards and outwards with a gentle backward curve, +their hinder edges working and wearing against the front edges of the +upper canines[179]. They appear externally to the mouth as tusks, the +form of the upper lip being modified to allow of their protrusion, but +are much less developed in the females than in the males. The teeth of +the molar series gradually increase in size and complexity from first +to last, and are arranged in contiguous series, except that the first +lower premolar is separated by an interval from the second. First and +second upper premolars with compressed crowns and two roots. The third +and fourth have an inner lobe developed on the crown, and an additional +pair of roots. The first and second true molars have quadrate crowns, +with four principal obtuse conical cusps, around which numerous accessory +cusps are clustered. The length of the third molar is nearly equal +(antero-posteriorly) to that of the first and second together, its crown +having, in addition to the four principal cusps, a large posterior talon +or heel, composed of numerous clustered conical cusps, and supported by +several additional roots. The lower molar teeth resemble generally those +of the upper jaw, but are narrower. Milk dentition: _i_ ³⁄₃, _c_ ¹⁄₁, +_m_ ³⁄₃; total 28,—the first permanent premolar having no predecessor in +this series. The third incisor, in both upper and lower jaws, is large, +developed before the others, and has much the size, form, and direction +of the canine. Vertebræ: C 7, D 13-14, L 6, S 4, C 20-24. The hairy +covering of the body varies much under different conditions of climate, +but when best developed, as in the European Wild Boar, consists of long +stiff bristles, mostly abundant on the back and sides, and of a close +softer curling undercoat. + +The skull of the Pigs (Figs. 103-105) has the axis of the face bent down +upon the basicranial axis, as is also the case with the Sheep. Its most +striking feature is the elevation and backward slope of the occipital +crest formed by the union of the supraoccipital and parietals. The broad +and flat frontals have small postorbital processes, which do not join the +zygomata, so that the orbits are open behind. The nasals are very long +and narrow; and the premaxillæ send up long nasal processes, stopping +short of the frontals. A peculiar prenasal bone is developed at the +anterior extremity of the mesethmoid, which serves to strengthen the +cartilaginous snout. The palate is long and narrow, and extends behind +the last molar tooth. In most species the occipital crest is more nearly +vertical than in the skull represented in Fig. 104. + +[Illustration: FIG. 103.—Left lateral view of the dentition of the Boar +(_Sus scrofa_), the roots of the teeth being exposed by removing the +external lamina of bone.] + +[Illustration: FIG. 104.—Left lateral view of the skull of _Sus +longirostris_. ⅕ natural size. (From Nehring.)] + +[Illustration: FIG. 105.—Frontal aspect of the cranium of _Sus +longirostris_, ⅕ natural size. (From Nehring.)] + +This genus occurs at present under three principal modifications or +subgenera. + +_A._—_Sus_ proper comprises a number of animals found in a wild state +throughout the greater part of Europe (except where exterminated by +human agency), the north of Africa, southern continental Asia, and +the great islands of the Malayan archipelago, Formosa, and Japan. The +following among others have been admitted by many zoologists as distinct +species:—_Sus scrofa_, the Wild Boar of Europe, Asia Minor, and North +Africa, once common throughout the British Isles; _S. sennaarensis_, +North-East Africa; _S. cristatus_, India; _S. vittatus_, Java, Borneo, +Amboyna, Batchian; _S. papuensis_, New Guinea; _S. timorensis_, Timor +and Rotti; _S. andamanensis_, Andaman Islands; _S. taëvanus_, Formosa; +_S. leucomystax_, Japan; _S. verrucosus_, Java, Borneo, Ceram; _S. +barbatus_, Borneo; _S. celebensis_, Celebes, Philippines, and Moluccas; +_S. longirostris_, Borneo and Java. The last four species form an +allied group in which the facial portion of the skull may be greatly +elongated; _S. barbatus_, and _S. celebensis_ being characterised by +the small size and simple structure of the talon of the third molars. +The skull of _S. longirostris_ is shown in Figs. 104 and 105. The small +_S. andamanensis_ also has very simple third molars. _S. vittatus_, _S. +leucomystax_, _S. cristatus_, _S. taëvanus_, and _S. papuensis_ form +another group, in which the third molar is generally of very complex +structure, more or less closely allied to the Wild Boar; and Dr. Nehring +is inclined to think that the whole five might be included under a +single specific name. This list will give some idea of the geographical +distribution of wild Pigs, but it must be borne in mind that through +the whole of this region, and in fact now throughout the greater part +of the habitable world, Pigs are kept by man in a domesticated state, +and it is still an open question whether some of the wild Pigs of the +islands named above may not be local races derived originally from, or +crossed with, imported domestic specimens. In New Zealand a wild or +rather “feral” race is already established, the origin of which is of +course quite recent, since it is well ascertained that no animal of the +kind ever lived upon the island until after its settlement by Europeans. +Whether the various breeds of domestic Pigs have been derived from +one or several sources is still unknown. As in so many similar cases, +there is no historic evidence upon the subject, and the researches of +naturalists, as Nathusius, Rütimeyer, Rolleston, Nehring, and others, who +have endeavoured to settle the question on anatomical evidence, have not +led to any satisfactory conclusions. It is, however, tolerably certain +that all the species or forms of wild Pigs enumerated above and all the +domestic races are closely allied, and it is probable (though of this +there has been no opportunity of proof) will breed freely together. +It is a curious circumstance that the young of all the wild kinds of +Pigs (so far as yet is known) present a uniform coloration, being dark +brown with longitudinal stripes of a paler colour, a character which +completely disappears after the first few months. On the other hand, +this peculiar marking is rarely seen in domestic Pigs in any part of +the world, although it has been occasionally observed. It is stated by +Darwin that the Pigs which have run wild in Jamaica and the semiferal +Pigs of New Granada have resumed this aboriginal character, and produce +longitudinally striped young; these must of course be the descendants +of domestic animals introduced from Europe since the Spanish conquest, +as before that time there were no true Pigs in the New World. Another +character by which the European domestic Pig differs from any of the wild +species is the concave outline of the frontal region of the skull, a form +still retained by the feral Pigs in New Zealand. + +_B._—The diminutive Pig of the Nipal, Terai, and Bhutan, _Sus salvanius_, +has been separated from the rest by Hodgson under the generic name of +_Porcula_, but all the alleged distinctive characters prove on more +careful investigation to have little real value. Owing to its retired +habits and power of concealment under bushes and long grass in the depths +of the great Sal Forest, which is its principal home, very little has +been known of this curious little animal, scarcely larger than a hare. +The acquisition of living specimens in the London Zoological Gardens has, +however, afforded opportunities for careful anatomical observation.[180] + +[Illustration: FIG. 106.—Wild Boar and Young.] + +_C._—Two well-marked species of African Swine have been with more reason +separated under the name of _Potamochœrus_. The dentition differs +from that of the true _Sus_, inasmuch as the anterior premolars have +a tendency to disappear; sometimes in adult specimens the first upper +premolar is retained, but it is usually absent, as well as the first +and often the second lower premolars. The molar teeth are also less +complex: the last especially having a much less developed talon. There +are likewise characteristic cranial differences. The two species are very +distinct in outward appearance and coloration. One is _S. africanus_, +the South African River-Hog, or Bosch-Vark, of a gray colour, and the +other _S. porcus_, the West African Red River-Hog (Fig. 107), remarkable +for its vivid colouring and long pencilled ears. It should be noted that +the young of both these species, as well as of the pigmy _S. salvanius_, +present the striped character of the true _Sus_, a strong indication of +close affinities, whereas in all the following forms this is absent. + +[Illustration: FIG. 107.—The Red River-Hog (_Sus porcus_). From Sclater, +_Guide to Animals in Zoological Society’s Gardens_, 1883, p. 183.] + +The genus _Sus_, in the above extended sense, is well represented in +the Tertiaries of the Old World from the period of the Lower Pliocene +upwards. In the Pliocene and Pleistocene of India _S. falconeri_ and +_S. karnuliensis_ are characterised by the extremely complex structure +of the molars, in which they show decided signs of approximation to +the Wart-Hogs; the same feature being exhibited by _S. phacochœroides_ +of the Algerian Pliocene. _S. titan_ and _S. giganteus_, of the Indian +Pliocene, together with _S. antiquus_ and _S. erymanthius_, of the +corresponding European deposits, are very large species characterised by +their comparatively simple molars; _S. titan_ being fully as large as a +Tapir. _S. hysudricus_ of the Pliocene of India, and _S. palæochœrus_ +of that of Europe, are smaller allied species not improbably related +to _S. andamanensis_, with which they agree in molar structure. _S. +arvernensis_, of the Upper Pliocene of France, appears to be allied to +_S. africanus_; while in the diminutive _S. punjabiensis_ of the Pliocene +of North-Western India we probably have the direct ancestor of _S. +salvanius_. + +[Illustration: FIG. 108.—Head of Babirusa (_Babirusa alfurus_).] + +_Babirusa._[181]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃; total 34. +The total number of teeth is therefore considerably reduced, the outer +upper incisor and the two anterior premolars of both jaws being absent. +The molars, especially the last, are smaller and simpler than in _Sus_; +but the great peculiarity of this genus is the extraordinary development +of the canines of the male. These teeth (Fig. 108) are ever-growing, +long, slender, and curved, and entirely without enamel covering. Those of +the upper jaw are directed upwards from their base, so that they never +enter the mouth, but piercing the skin of the face, resemble horns rather +than teeth, and curve backwards, downwards, and finally often forwards +again, almost or quite touching the skin of the forehead. Vertebra: +C 7, D 13, L 16, S 4. There is but one species (_B. alfurus_), found +only in the islands of Celebes and Buru. Its external surface is almost +entirely devoid of hair. With regard to the curiously modified dentition, +Wallace (_Malay Archipelago_, vol. i. p. 435) makes the following +observations:—“It is difficult to understand what can be the use of these +horn-like teeth. Some of the old writers supposed that they served as +hooks by which the creature could rest its head on a branch. But the +way in which they usually diverge just over and in front of the eye has +suggested the more probable idea, that they serve to guard these organs +from thorns and spines while hunting for fallen fruits among the tangled +thickets of rattans and other spiny plants. Even this, however, is not +satisfactory, for the female, who must seek her food in the same way, +does not possess them. I should be inclined to believe rather that these +tusks were once useful, and were then worn down as fast as they grew, but +that changed conditions of life have rendered them unnecessary, and they +now develop into a monstrous form, just as the incisors of the Beaver and +Rabbit will go on growing if the opposite teeth do not wear them away. In +old animals they reach an enormous size, and are generally broken off as +if by fighting.” + +_Phacochœrus._[182]—The Wart-Hogs, so called from the large cutaneous +lobes projecting from each side of the face, have the teeth still more +remarkably modified than in _Babirusa_. The milk-dentition, and even +the early condition of the permanent dentition, is formed on the same +general type as that of _Sus_, except that certain of the typical teeth +are absent, the formula being _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ³⁄₂, _m_ ³⁄₃, total +34; but as age advances all the teeth have a tendency to disappear, +except the canines and the posterior molars, which in some cases are the +only teeth left in the jaws, and attain an extraordinary development. +The upper canines especially are of great size, and curve outwards, +forwards, and upwards. Their enamel covering is confined to the apex, and +soon wears away. The lower canines are much more slender, but follow the +same curve: except on the posterior surface, their crowns are covered +with enamel. Unlike those of the Babirusa, the canines of the Wart-Hog +are large in both sexes. The third molar tooth of both jaws is of great +size, and presents a structure at first sight unlike that of any other +mammal, being composed of numerous (22-25) parallel cylinders or columns, +each with pulp-cavity, dentine, and enamel covering, and packed together +with cement. Careful examination will, however, show that a similar +modification to that which has transformed the comparatively simple molar +tooth of the Mastodon into the extremely complex grinder of the Indian +Elephant has served to change the tooth of the common Pig into that of +_Phacochœrus_, and, as already mentioned, some of the fossil Indian and +African species of _Sus_ indicate the mode in which this transition came +about. The tubercles which cluster over the surface of the crown of the +molars of the common Pig are elongated and drawn out into columns in the +Wart-Hog, as the low transverse ridges of the Mastodon’s tooth become the +leaf-like plates of the Elephant’s. + +Two species of this genus are commonly but rather doubtfully +distinguished:—_P. africanus_, Ælian’s Wart-Hog, widely distributed +over the continent; and _P. æthiopicus_, Pallas’s Wart-Hog, confined to +South-Eastern Africa. In specimens attributed to the latter species the +dentition reaches its most complete reduction, as in adult animals the +upper incisors are absent and the lower ones worn down to the roots. + + +_Family_ DICOTYLIDÆ. + +Snout as in _Suidæ_. Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total +38. Incisors rooted; upper canines directed downwards, with sharp cutting +hinder edges. Toes, four on the fore feet and three on the hind feet (the +fifth wanting). Stomach complex. A cæcum. Confined to the New World. + +_Dicotyles._[183]—The teeth of the Peccaries (_Dicotyles_) differ from +those of the true Pigs (_Sus_) numerically in wanting the upper outer +incisor and the anterior premolar on either side of each jaw, and also +in the circumstance that the last premolar is nearly as complex as the +molars. The upper canines have their points directed downwards, not +outwards or upwards as in the Boars, and are very sharp, with cutting +hinder edges, and completely covered with enamel until worn. The lower +canines are large, directed upwards and outwards, and slightly curved +backwards. The premolar and molar teeth form a continuous series, +gradually increasing in size from the first to the last. The true molars +have square quadricuspidate crowns. The stomach is much more complex +than in the true Pigs, almost approaching that of the ruminants. In +the feet the two middle (third and fourth) metapodial bones, which are +completely separate in the Pigs, are united at their upper ends, as +in the ruminants. On the fore foot the two (second and fifth) outer +toes are equally developed as in Pigs, but on the hind foot, although +the inner (or second) is present, the outer (or fifth) toe is entirely +wanting, giving an unsymmetrical appearance of the member, very unusual +in Artiodactyles. Vertebræ: C 7, D 14, L 5, S 4, C 7. As in the Pigs, +the snout is truncated, and the nostrils are situated in its flat, +expanded, disc-like termination. The ears are rather small, ovate, and +erect; and there is no external appearance of a tail. The surface of +the body is well covered with thick bristly hair, and rather behind +the middle of the back is a large and peculiar gland, which secretes an +oleaginous substance with a powerful musky odour. This was mistaken by +the old travellers for a second navel, a popular error which suggested to +Cuvier the name of _Dicotyles_. When the animal is killed for food, it +is necessary speedily to remove this gland, otherwise it will taint the +whole flesh so as to render it uneatable. + +[Illustration: FIG. 109.—The Collared Peccary (_Dicotyles tajacu_).] + +There are two species,[184] so nearly allied that they will breed +together freely in captivity. Unlike the true Pigs, they never appear +to produce more than two young ones at a birth. The Collared Peccary +(_D. tajacu_, Linn., _torquatus_, Cuvier), Fig. 109, ranges from the +Red River of Arkansas through the forest districts of Central and South +America as far as the Rio Negro of Patagonia. Generally it is found +singly or in pairs, or at most in small herds of from eight to ten, +and is a comparatively harmless creature, not being inclined to attack +other animals or human beings. Its colour is dark gray, with a white +or whitish band passing across the chest from shoulder to shoulder. +The length of the head and body is about 36 inches. The White-lipped +Peccary or Warree (_D. labiatus_, Cuvier) is rather larger, being about +40 inches in length, of a blackish colour, with the lips and lower jaw +white. Its range is less extensive, since it is not found farther north +than British Honduras or south of Paraguay. It is generally met with in +large herds of from fifty to a hundred or more individuals, and is of +a more pugnacious disposition than the former species, and capable of +inflicting severe wounds with its sharp tusks. A hunter who encounters +a herd of them in a forest has often to climb a tree as his only chance +of safety. Both species are omnivorous, living on roots, fallen fruits, +worms, and carrion; and when they approach the neighbourhood of villages +and cultivated lands they often inflict great devastation upon the crops +of the inhabitants. + +Remains of the two existing species of Peccary, as well as of one +much larger extinct form, are found in the cavern-deposits of Brazil; +while large Peccaries also occur in the Pleistocene of the United +States, which, although they have been referred to a distinct genus, +_Platygonus_, on account of their relatively smaller incisors and +somewhat simpler premolars, may well be included in _Dicotyles_. + +[Illustration: FIG. 110.—The three left upper molars of _Hyotherium +perimense_, from the Pliocene of India.] + +_Allied Extinct Genera._—In the Tertiary deposits of both the Old and +New World occur remains of Pig-like animals which, so far as we can +judge, appear to connect the Peccaries so closely with the true Pigs +as to render the _Dicotylidæ_ really inseparable from the _Suidæ_. +Of these the American genus _Chænohyus_ has the lower canine with a +triangular cross section and received into a notch in the upper jaw, +as in the Peccaries, but the fourth upper premolar is simpler than the +molars, as in the under-mentioned genus _Hyotherium_. The typical forms +have only three premolars, but in others, which it has been proposed +to separate generically as _Bothriolabis_, there are four of these +teeth. _Hyotherium_, of the Pliocene and Miocene of the Old World, is +a generalised form allied both to _Sus_ and _Dicotyles_ as well as to +certain extinct genera. The upper molars (Fig. 110) are characterised +by their square crowns, the last having no distinct third lobe, and +coming into use before the first is much worn, while the last premolar +is simpler than the true molars. The canines, which have an oval section +and are scarcely larger than the incisors, are not received into a notch +in the upper jaw. In the Pliocene of India there occurs an apparently +allied genus known as _Hippohyus_, in which the crowns of the molars +are much taller, and have lateral infoldings of the enamel, producing +a very complex pattern on the worn crowns. The European Miocene genus +_Listriodon_, with the dental formula _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ +³⁄₃, differs from all the preceding in having the anterior and posterior +pairs of tubercles of the molars united into ridges running across their +crowns, so that these teeth resemble the lower molars of the Tapir. The +genus is also found in the Lower Pliocene of India. + + +EXTINCT TRANSITIONAL ARTIODACTYLES. + +In this place it will be convenient to notice briefly a few of the +extinct types of Tertiary Artiodactyles which connect the existing +bunodont Suina with the more specialised selenodont groups mentioned +below so closely as to show that in a strictly palæontological +classification such groups cannot be maintained. It should be mentioned +that while some of these extinct forms were in all probability actual +ancestral links between the bunodonts and selenodonts, others, like +the Anoplotheres, died out entirely without giving rise to any more +specialised descendants. + +[Illustration: FIG. 111.—The imperfect third left upper molar of +_Hyopotamus giganteus_, Miocene, India. (From the _Palæontologia +Indica_.)] + +_Chœropotamidæ._—In this family the molars are intermediate in +structure between those of the _Suidæ_ and the next family. The upper +ones have very broad crowns, with the five columns arranged as in +_Anthracotherium_; while the premolars are not secant, and may be +very large. The best known forms are the small _Cebochœrus_ of the +Phosphorites of Central France; _Chœropotamus_ of the Upper Eocene, the +type species of which was of the size of a large Pig, with the dental +formula _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₃, _m_ ³⁄₃, and no distinctly selenodont +structure in the molars; the much larger _Elotherium_, from the Upper +Eocene and Lower Miocene of both the Old and New Worlds, which presents +the very rare feature of the absence of a third lobe to the last lower +molar; and the equally large _Tetraconodon_ of the Pliocene of India, +in which this third lobe was present and the premolars were of enormous +size. The remarkable North American Eocene genus _Achænodon_ should +perhaps also be placed here. + +[Illustration: FIG. 112.—A right upper molar of _Merycopotamus pusillus_, +Pliocene, India. (From the _Palæontologia Indica_.)] + +_Anthracotheriidæ._—The genera _Anthracotherium_ and _Hyopotamus_, of +the upper Eocene and Miocene, have the typical Eutherian dental formula; +the upper molars (Fig. 111) carrying three columns on the anterior and +two on the posterior half of the crown, all of which are of a more or +less decidedly selenodont structure. The mandible has a descending +flange at the angle. The figured tooth (in which the antero-internal and +antero-median columns are imperfect) may be compared with the diagram +given in Fig. 5, p. 32, when the homology of the columns or tubercles +will be at once apparent, the broken antero-median column representing +the protoconule. Some of the species are of large size, while others are +comparatively small. + +_Merycopotamus._—The genus _Merycopotamus_ of the lower Pliocene +of India may be regarded as an Anthracotheroid which has lost the +antero-median column to the upper molars (Fig. 112), so that these teeth +are consequently quadrituberculate; and may thus be regarded as typical +examples of the brachy-selenodont modification of molar structure. + +_Cotylopidæ._—The Miocene genus _Cotylops_ (_Oreodon_[185]) is the type +of a large American family in which the upper molars are selenodont and +usually have four columns, while the lower canine is approximated to +the incisors and its form and function assumed by the first premolar. +The last upper premolar is simpler than the molars. There is no flange +to the angle of the mandible; and the feet have four digits. The +affinities of this peculiar family are probably widely spread, but they +may have been derived from the _Anthracotheriidæ_. The type genus has +the full Eutherian dentition, but in some of the more specialised forms +(_Cyclopidius_) the upper incisors may be wanting, and large vacuities +occur in the lachrymal region. The generalised genus _Protoreodon_, of +the Upper or Uinta Eocene, has five cusps on the upper molars, arranged +as in the _Anthracotheriidæ_. The pollex is retained in the manus of the +type genus. + +[Illustration: FIG. 113.—Restoration of _Anoplotherium commune_ (Upper +Eocene). Cuvier.] + +The family may be divided into subfamilies as follows:— + + I. Upper molars with four columns. + + 1. Orbits open, no lachrymal fossa, a diastema, the last + upper premolar with two outer columns, outer wall of + upper molars concave and inclined inwards.—_Agriochœrinæ_ + (_Agriochœrus_). + + 2. Orbits closed, a lachrymal fossa, no diastema, the last + upper premolar with one outer column; outer wall of upper + molars flattened.—_Cotylopinæ_ (_Cotylops_, _Eporeodon_, + _Merycochœrus_, _Cyclopidius_, etc.) + + II. Upper molars with five columns.—_Protoreontinæ_ (_Protoreodon_). + +_Anoplotheriidæ._—This family includes several Upper Eocene European +genera, with selenodont upper molars, carrying five columns arranged as +those in _Anthracotherium_. One of the earliest known, _Anoplotherium_, +was fully described by Cuvier from remains found in the Paris gypsum-beds +(Upper Eocene). Its forty-four teeth formed a series unbroken by a gap +or diastema, and were of uniform height (as in Man alone of existing +mammals). Its tail was long, with large chevron bones underneath, not +usually found in Ungulates, and there were either three or two toes on +each foot. It was in many respects a much-specialised form, apparently +not on the line of descent of any of the existing groups. + +_Dacrytherium_ is an allied genus whose dentition leads on to that of the +smaller _Xiphodon_. The latter genus is characterised by the compressed +and elongated form of the crowns of the first three premolars, which thus +approximate to those of the Chevrotains. There were only two functional +digits to the feet. The so-called _Hyopotamus picteti_, of the Swiss +Eocene, is a species of _Dacrytherium_. + +_Cænotheriidæ._—The typical representatives of this family are small +animals not larger than the Chevrotains, with the full complement of +teeth, generally no marked gap in the series, and the crowns of the upper +molars carrying two columns on the anterior and three on the posterior +half of the crown—precisely the reverse of the arrangement obtaining in +the _Anthracotheriidæ_. The known forms are from the Upper Eocene and +Lower Miocene of Europe. In _Cænotherium_ the molars are selenodont, +while they are bunodont in _Dichobunus_. _Homacodon_, of the Bridger +Eocene of the United States, is closely allied to the latter. The first +lower premolar of _Dichobunus_ assumes the form and function of a canine. +_Spaniotherium_ (_Metriotherium_) is a much larger form, in which the +molars are not unlike those of _Anthracotherium_, if the arrangement of +the cusps were reversed; it occurs in the Eocene Phosphorites of France. +It is suggested that the _Tylopoda_ may have originated from this group. + +_Tapirulus_ is a small Eocene Artiodactyle with the columns of the upper +molars, which are somewhat like those of _Hyopotamus_, tending to form +transverse ridges; its family position is uncertain. + +_Dichodontidæ._—The European genera included in this family all have +quadritubercular selenodont molars, and show signs of approximating +more or less closely to existing types. _Dichodon_, from the Upper +Eocene and Lower Miocene, has the full complement of teeth, which show +no diastema, and have low crowns. The fourth upper premolar has four +columns, like the true molars, and the corresponding lower tooth three +complete lobes; these features being unknown in any other Selenodonts. +In _Lophiomeryx_, of the same beds, the somewhat higher crowns of the +molars approximate to those of the _Cervidæ_, but the hinder lobes of +the upper ones are imperfectly developed; the genus may be allied, +to the _Tragulidæ_. In the small _Gelocus_, of the Lower Miocene, +the molars are not unlike those of _Dichodon_; but the navicular and +cuboid bones of the tarsus were fused together, and the metatarsals had +united to form a “cannon-bone,” although the metacarpals still remained +distinct. It is not improbable that upper incisors were wanting; and it +has been suggested that we have in this genus the ancestral type of the +_Tragulidæ_ and _Cervidæ_. + + +TYLOPODA. + + +_Family_ CAMELIDÆ. + +This group is represented at the present day by the two species of +Camels of the Old World and the Llamas of South America, collectively +constituting the family _Camelidæ_. The special characters which +the Llamas and Camels have in common, and the combination of which +distinguishes them from the rest of the Artiodactyles, are as follows. +The premaxillæ have the full number of incisor teeth in the young state, +and the outermost is persistent through life as an isolated laniariform +tooth. The canines are present in both jaws, and those of the mandible +are differentiated from the long, procumbent, and spatulate incisors, +being suberect and pointed. The crowns of the true molars belong to the +crescentic or selenodont type, and are very hypsodont; but one or more +of the anterior premolars is usually detached from the series, and is of +simple pointed form. The auditory bulla is filled with cancellous tissue. +The hinder part of the body is much contracted, and the femur long and +vertically placed, so that the knee-joint is lower in position, and the +thigh altogether more detached from the abdomen than in most quadrupedal +mammals. The limbs are long, but with only the third and fourth digits +developed; no traces of any of the others being present. The trapezoid +and magnum of the carpus, and the cuboid and navicular of the tarsus +are distinct. The two metapodial bones of each limb are confluent for +the greater part of their length, though separated for a considerable +distance at the lower end. Their distal articular surfaces, instead of +being pulley-like, with deep ridges and grooves, as in other recent +Artiodactyles, are simple, rounded, and smooth. The proximal phalanges +are expanded at their distal ends, and the wide, depressed middle +phalanges are embedded in a broad cutaneous pad, forming the sole of the +foot, on which the animal rests in walking, instead of on the hoofs. The +ungual phalanges are very small and nodular, not flattened on their inner +or opposed surfaces, and not completely encased in hoofs, but bearing +nails on their upper surface only. The cervical region is long and +flexuous, and the vertebræ of which it is composed are remarkable for +the position of the canal for the transmission of the vertebral artery, +which does not perforate the transverse process, but passes obliquely +through the anterior part of the pedicle of the arch (a condition only +found in two other genera of mammals, _Macrauchenia_ and _Myrmecophaga_). +There are no horns or antlers. Though these animals ruminate, the +stomach differs considerably in the details of its construction from +that of the Pecora. The interior of the rumen or paunch has no villi +on its surface, and there is no distinct psalterium or manyplies. Both +the first and second compartments are remarkable for the presence of a +number of pouches or cells in their walls, with muscular septa, and a +sphincter-like arrangement of their orifices, by which they can be shut +off from the rest of the cavity, and into which the fluid portion only +of the contents of the stomach is allowed to enter.[186] The placenta +is diffuse, as in the Suina and Tragulina, not cotyledonary, as in the +Pecora. Finally, the _Camelidæ_ differ not only from other Ungulates, +but from all other mammals, in the fact that the red corpuscles of the +blood, instead of being circular in outline, are oval, as in the inferior +vertebrated classes. + +_Camelus._[187]—Dentition of adult: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ³⁄₂, _m_ ³⁄₃; +total 34. First upper premolar simple, placed immediately behind the +premaxillæ, and separated by a long diastema from the penultimate tooth +of that series. Lower incisors somewhat proclivous, the outermost the +largest. Skull elongated, with an overhanging occiput, orbits completely +surrounded by bone, and the premaxillæ not articulating with the +arched and somewhat elongated nasals. Vertebræ: C 7, D 12, L 7, S 4, C +13-15. Ears comparatively short and rounded. One or two dorsal adipose +humps. Feet broad, with the toes very imperfectly separated. Tail well +developed, tufted at the end. Hair nearly straight, and not woolly. Size +very large and bulky. + +The genus is now represented by two species, viz. the single-humped +Arabian Camel (_Camelus dromedarius_), and the double-humped Bactrian +Camel (_C. bactrianus_, Fig. 114).[188] The former is quite unknown +in a wild state, but it is reported that wild Bactrian Camels occur +in the more remote parts of Turkestan. The latter species is found in +a domesticated state throughout a large portion of Turkestan and the +neighbouring region, extending as far as the Crimea in the west and +to Lake Baikal and Pekin in the east. It is a heavier and more clumsy +animal than the Arabian Camel, with thicker hair, shorter legs, and the +feet more callous and better adapted to a hard ground. The hair is most +developed upon the top of the head, neck, humps, arm, and wrist. Bactrian +Camels are occasionally brought over the stupendous mountain passes south +of Yarkand to within a few days’ journey of Leh, in Kashmir territory. + +[Illustration: FIG. 114.—The Bactrian Camel (_Camelus bactrianus_).] + +The Arabian Camel is commonly employed as a beast of burden in Africa +and India, and has of late years been introduced into Australia for +the same purpose; it is especially valuable in crossing long stretches +of arid desert from its power of existing for a considerable period of +time without water. The female goes fully eleven months with young, and +produces but a single calf at a birth, which is suckled for a whole +year. In disposition the Camel is surly and subject to furious outbursts +of temper, especially during the rutting season. At such periods the +male utters a peculiar and highly disagreeable bubbling noise in its +throat, well known to all who have travelled in India with Camels as +their transport. It has been said that the Camel is docile, but Palgrave +observes:— + +“If docile means stupid, well and good; in such a case the Camel is the +very model of docility. But if the epithet is intended to designate an +animal that takes an interest in its rider so far as a beast can, that +in some way understands his intentions, or shares them in a subordinate +fashion, that obeys from a sort of submissive or half-fellow-feeling with +his master, like the horse or elephant, then I say that the camel is by +no means docile—very much the contrary. He takes no heed of his rider, +pays no attention whether he be on his back or not, walks straight on +when once set agoing, merely because he is too stupid to turn aside, +and then should some tempting thorn or green branch allure him out of +the path, continues to walk on in the new direction simply because he +is too dull to turn back into the right road. In a word, he is from +first to last an undomesticated and savage animal, rendered serviceable +by stupidity alone, without much skill on his master’s part, or any +co-operation on his own save that of an extreme passiveness. Neither +attachment nor even habit impress him; never tame, though not wide-awake +enough to be exactly wild.” The two species breed together freely, +and among the Yourouks of Asia Minor, hybrids, or mules, the produce +generally of a male Bactrian and a female Arabian camel are preferred to +either of the pure breeds. + +Fossil remains of Camels are found in the Pliocene of the Siwalik Hills +in Northern India. These differ from the existing representatives of the +genus in having a vertical ridge at the antero-external angle of the +lower molars, whereby they resemble _Auchenia_; their cervical vertebræ +are also intermediate in structure between those of the latter and the +existing Camels. A fossil Camel is also found in the Pleistocene of +Algeria. + +_Auchenia._[189]—Dentition of adults normally: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, +_m_ ³⁄₃; total 32—one of the lower premolars may, however, be wanting. +In the upper jaw there is a compressed, sharp, pointed laniariform +incisor near the hinder edge of the premaxilla, followed, in the male at +least, by a moderate-sized, pointed, curved true canine in the anterior +part of the maxilla. The isolated canine-like premolar which follows +in the Camels is not present. The teeth of the molar series, which are +in contact with each other, consist of two very small premolars (the +first almost rudimentary) and three broad molars, constructed generally +like those of _Camelus_. In the lower jaw the three incisors are long, +spatulate, and procumbent; the outer ones being the smallest. Next to +these is a curved, suberect canine, followed after an interval by an +isolated, minute, and often deciduous simple conical premolar; then a +contiguous series of one premolar and three molars, which differ from +those of existing species of _Camelus_ in having a small accessory +column at the anterior outer edge. The skull generally resembles that +of _Camelus_, the relatively larger brain-cavity and orbits and less +developed cranial ridges being due to its smaller size. The nasal bones +are shorter and broader, and are joined by the premaxillæ. Vertebræ: +C 7, D 12, L 7, S 4, C 15-20. Ears rather long and pointed. No dorsal +hump. Feet narrow, the toes being more separated than in the camels, +each having a distinct plantar pad. Tail short. Hairy covering long and +woolly. Size (in existing forms) smaller, and general form lighter than +in the Camels. At present and within historic times the genus is entirely +confined to the western side and southernmost parts of South America, but +fossil remains have been found in the caves of Brazil, in the pampas of +the Argentine republic, and in Central and North America. + +[Illustration: FIG. 115.—Llama (_Auchenia glama_), from an animal living +in the Gardens of the Zoological Society of London.] + +The word Llama, sometimes spelt Lama, is the name by which the Peruvians +designated one of a small group of closely allied animals, which, before +the Spanish conquest of America, were the only domesticated hoofed +mammals of the country, being kept, not only for their value as beasts +of burden, but also for their flesh, hides, and wool,—in fact, supplying +in the domestic economy of the people the place of the horse, the ox, +the goat, and the sheep of the Old World. The word is now sometimes +restricted to one particular species or variety of the group, and +sometimes used in a generic sense to cover the whole. Although they were +often compared by early writers to sheep, and spoken of as such, their +affinity to the camel was very soon perceived, and they were included +in the genus _Camelus_ in the _Systema Naturæ_ of Linnæus. They were, +however, separated by Cuvier in 1800 under the name of _Lama_, changed +by Illiger in 1811 to _Auchenia_ (in allusion to the great length of +neck, αὐχήν), a term afterwards adopted by Cuvier, and almost universally +accepted by systematic zoologists, although there has been of late a +disposition to revive the earlier name. + +In essential structural characters, as well as in general appearance and +habits, all the animals of this genus very closely resemble each other, +so that the question as to whether they should be considered as belonging +to one, two, or more species has been one which has led to a large amount +of controversy among naturalists. The question has been much complicated +by the circumstances of the great majority of individuals which have come +under observation being either in a completely or partially domesticated +state, and descended from ancestors which from time immemorial have been +in like condition, one which always tends to produce a certain amount +of variation from the original type. It has, however, lost much of its +importance since the doctrine of the distinct origin of species has been +generally abandoned. + +[Illustration: FIG. 116.—Head of Vicugna, from an animal living in the +Gardens of the Zoological Society of London.] + +The four forms commonly distinguished by the inhabitants of South America +are recognised by some naturalists as distinct species, and have had +specific designations attached to them, though usually with expressions +of doubt, and with great difficulties in defining their distinctive +characteristics. These are (1) the Llama, _Auchenia glama_ (Linn.), or +_Lama peruana_ (Tiedemann); (2) the Alpaca, _A. pacos_ (Linn.); (3) the +Guanaco or Huanaco, _A. huanacus_ (Molina); and (4) the Vicugna, _A. +vicugna_ (Molina), or _A. vicunna_, (Cuv.) The first and second are only +known in the domestic state, and are variable in size and colour, being +often white, black, or piebald. The third and fourth are wild, and of +a nearly uniform light-brown colour, passing into white below. They +certainly differ from each other, the Vicugna being smaller, more slender +in its proportions, and having a shorter head (Fig. 116) than the Guanaco +(Fig. 117). It may therefore, according to the usual view of species, +be considered distinct. It lives in herds on the bleak and elevated +parts of the mountain range bordering the region of perpetual snow, +amidst rocks and precipices, occurring in various suitable localities +throughout Peru, in the southern part of Ecuador, and as far south as the +middle of Bolivia. Its manners very much resemble those of the Chamois +of the European Alps; and it is as vigilant, wild, and timid. The wool +is extremely delicate and soft, and highly valued for the purposes of +weaving, but the quantity which each animal produces is not great. + +[Illustration: FIG. 117.—Head of Guanaco, from an animal living in the +Gardens of the Zoological Society of London.] + +The Guanaco has an extensive geographical range, from the highlands of +the Andean region of Ecuador and Peru to the open plains of Patagonia, +and even the wooded islands of Tierra del Fuego. It constitutes the +principal food of the Patagonian Indians, and its skin is invaluable +to them, as furnishing the material out of which their long robes are +constructed. It is about the size of a European Red Deer, and is an +elegant animal, being possessed of a long, slender, gracefully curved +neck and fine legs. Dr. Cunningham,[190] speaking from observation on +wild animals, says:— + +“It is not easy to describe its general appearance, which combines some +of the characters of a camel, a deer, and a goat. The body, deep at the +breast but very small at the loins, is covered with long, soft, very +fine hair, which on the upper parts is of a kind of fawn-colour, and +beneath varies from a very pale yellow to the most beautiful snow-white. +The head is provided with large ears, in general carried well back, and +is covered with short grayish hair, which is darkest on the forehead. +Occasionally the face is nearly black. As a rule it lives in flocks of +from half a dozen to several hundreds, but solitary individuals are now +and then to be met with. They are very difficult to approach sufficiently +near to admit of an easy shot, as they are extremely wary, but, on being +disturbed, canter off at a pace which soon puts a safe distance between +them and the sportsman, even though he should be mounted. Despite their +timidity, however, they are possessed of great curiosity, and will +sometimes advance within a comparatively short distance of an unknown +object, at which they will gaze fixedly till they take alarm, when they +effect a speedy retreat. Their cry is very peculiar, being something +between the belling of a deer and the neigh of a horse. It would be +difficult to overestimate their numbers upon the Patagonian plains; for +in whatever direction we walked we always came upon numbers of portions +of their skeletons and detached bones.” + +Darwin, who has given an interesting account of the habits of the Guanaco +in his _Naturalist’s Voyage_, says that they readily take to the water, +and were seen several times at Port Valdes swimming from island to island. + +The Llama is only known as a domestic animal, and is chiefly met with +in the southern part of Peru. Burmeister, a very competent writer +on the subject, says that he is perfectly satisfied that it is the +descendant of the wild Guanaco, an opinion opposed to that of Tschudi. It +generally attains a larger size than the Guanaco, and is usually white +or spotted with brown or black, and sometimes altogether black. The +earliest and often-quoted account of this animal by Agustin de Zarate, +treasurer-general of Peru in 1544, will bear repeating as an excellent +summary of the general character and uses to which it was put by the +Peruvians at the time of the Spanish conquest. He speaks of the Llama +as a sheep, observing, however, that it is camel-like in shape though +destitute of a hump:— + +“In places where there is no snow the natives want water, and to supply +this they fill the skins of sheep with water and make other living sheep +carry them; for, it must be remarked, these sheep of Peru are large +enough to serve as beasts of burden. They can carry about one hundred +pounds or more, and the Spaniards used to ride them, and they would +go four or five leagues a day. When they are weary they lie down upon +the ground; and as there are no means of making them get up, either by +beating or assisting them, the load must of necessity be taken off. +When there is a man on one of them, if the beast is tired and urged to +go on, he turns his head round and discharges his saliva, which has an +unpleasant odour, into the rider’s face. These animals are of great +use and profit to their masters, for their wool is very good and fine, +particularly that of the species called Pacas, which have very long +fleeces; and the expense of their food is trifling, as a handful of maize +suffices them, and they can go four or five days without water. Their +flesh is as good as that of the fat sheep of Castile. There are now +public shambles for the sale of their flesh in all parts of Peru, which +was not the case when the Spaniards came first; for when one Indian had +killed a sheep his neighbours came and took what they wanted, and then +another Indian killed a sheep in his turn.” + +The disagreeable habit here noticed of spitting in the face of persons +whose presence is obnoxious is common to all the group, as may be daily +witnessed in specimens in confinement in the menageries of Europe. One +of the principal labours to which the Llamas were subjected at the time +of the Spanish conquest was that of bringing down ore from the mines in +the mountains. Gregory de Bolivar estimated that in his day as many as +three hundred thousand were employed in the transport of the produce of +the mines of Potosi alone; but since the introduction of horses, mules, +and donkeys the importance of the Llama as a beast of burden has greatly +diminished. + +The Alpaca, though believed by many naturalists to be a variety of the +Vicugna, is more probably, like the Llama, derived from the Guanaco, +having the naked callosities on the hind limbs, and the relatively +large skull of the latter. It is usually found in a domesticated or +semi-domesticated state, being kept in large flocks which graze on the +level heights of the Andes of southern Peru and northern Bolivia at an +elevation of from 14,000 to 16,000 feet above the sea-level, throughout +the year. It is smaller than the Llama, and, unlike that animal, is not +used as a beast of burden, but is valued only for its wool, of which the +Indian blankets and ponchas are made. Its colour is usually dark brown or +black. + +Mention has already been made of the occurrence of fossil Llamas in +America, but some diversity of view obtains as to the generic position +of some of these forms, owing to variations in their dental formula. +Remains apparently referable to the existing species occur in the +cavern-deposits of Brazil. In the Pleistocene of Mexico we meet with +_A. (Palauchenia) magna_, which attained the size of a Camel, and had +always two, and occasionally three, lower premolars; while in one South +American Pleistocene species, which has been generically separated as +_Hemiauchenia_, there were invariably three premolars in each jaw. In _A. +(Holomeniscus) hesterna_, from the Pleistocene of North America, which +was equal in size to _A. magna_, the premolars were reduced to one in +each jaw; and the same condition obtains in _A. (Eschatius) vitakeriana_, +where, however, the upper one is of simpler structure. + +_Extinct Cameloids._—Until within the last few years the existence of +two genera having so very much in common as the Camels and the Llamas, +and yet so completely isolated geographically, had not received any +satisfactory explanation; for the old idea that they in some way +“represented” each other in the two hemispheres of the world was a mere +fancy without philosophical basis. The discoveries made mostly within +the past twenty years of a vast and previously unsuspected extinct fauna +in the American continent of the Tertiary period, as interpreted by +Leidy, Cope, Marsh, and others, has thrown a flood of light upon the +early history of this family, and upon its relations to other mammals. + +There have been found in these regions many Camel-like animals exhibiting +different generic modifications; and, what is more interesting, a gradual +series of changes, coinciding with the antiquity of the deposits in which +they are found, have been traced from the thoroughly differentiated +species of the modern epoch down through the Pliocene to the early +Miocene beds, where, their characters having become by degrees more +generalised, they have lost all that specially distinguishes them as +_Camelidæ_, and are merged into forms common to the ancestral type of all +the other sections of the Artiodactyles. Hitherto none of these annectant +forms have been found in any of the fossiliferous strata of the Old +World; and it may therefore be fairly surmised (according to the evidence +at present before us) that America was the original home of the Tylopoda, +and that the true Camels have passed over into the Old World, probably by +way of the north of Asia, where we have every reason to believe there was +formerly a free communication between the continents, and then, gradually +driven southward, perhaps by changes of climate, having become isolated, +have undergone some further special modifications; while those members +of the family that remained in their original birthplace have become, +through causes not clearly understood, restricted solely to the southern +or most distant part of the continent. The occurrence in the dentition of +the fossil Siwalik Camels of a feature now found only in _Auchenia_ is +especially interesting from this point of view. + +Briefly referring to some of these fossil types, we may note that +_Pliauchenia_, of the Loup Fork beds (Lower Pliocene) of the United +States, has three lower premolars, while in _Procamelus_ there were four +of these teeth. In _Protolabis_ of the Miocene we have a more generalised +form, in which the dental formula is _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ +³⁄₃; and from this type a transition may be traced to _Poëbrotherium_, +which, while having the same dental formula, was no larger than a Fox, +and had the third and fourth metacarpals separate, with rudiments of the +fourth and fifth. The earliest undoubted representative of the group is +_Leptotragulus_, of the Uinta Eocene, which appears to have been closely +allied to _Poëbrotherium_. It is, however, probable that the first +lower premolar was wanting; while the other premolars of the mandible +were much shorter antero-posteriorly than in the last-named genus. The +manus, moreover, appears to have been less reduced, the second metacarpal +retaining its connection with the magnum. It is suggested that +_Leptotragulus_ may have been derived from the Bunodont genus _Homacodon_ +of the Bridger Eocene, mentioned among the _Cænotheriidæ_. + + +TRAGULINA. + + +_Family_ TRAGULIDÆ. + +No teeth in premaxillæ. Upper canines well developed, especially in +the males; narrow and pointed. Lower canines incisiform. No caniniform +premolars in either jaw, all the premolars except the last in the upper +jaw being secant. Molariform teeth in a continuous series, consisting +of _p_ ³⁄₃, _m_ ³⁄₃. Odontoid process of axis vertebra conical. Fibula +complete. Four complete toes on each foot. The middle metapodials +generally confluent, the outer ones (second and fifth) very slender +but complete, _i.e._ extending from the carpus or tarsus to the digit. +Navicular, cuboid, and ectocuneiform bones of tarsus united. Tympanic +bullæ of skull filled with cancellar tissue. No frontal appendages. +Ruminating, but the stomach with only three distinct compartments, the +manyplies or third cavity of the stomach of the Pecora being rudimentary. +Placenta diffused. + +This section is represented only by the single family _Tragulidæ_, +containing a few animals of small size, commonly known as Chevrotains, +intermediate in their structure between the Deer, the Camels, and the +Pigs. The large size of the canines of the male and the absence of +horns caused them to be associated formerly with _Moschus_, one of the +_Cervidæ_; hence they are often spoken of as “Pigmy Musk-Deer,” although +they have no musk-secreting gland, or, except in the above-named trivial +external characters, no special affinities with the true Musk-Deer. +There has scarcely been a more troublesome and obdurate error in zoology +than in this association of animals so really distinct. It has been +troublesome, not only in preventing a just conception of the relations of +existing Artiodactyles, but also in causing great confusion and hindrance +in palæontological researches among allied forms; and most obdurate, +inasmuch as all that has been recently done in advancing our knowledge +of both groups has not succeeded in eradicating it, not only from nearly +every one of our zoological text-books, whether British or Continental, +but even from works of the highest scientific pretensions. + +The family is now generally divided into two genera. + +_Tragulus_,[191] containing the smallest of the existing Ungulates, +animals having more of the general aspects and habits of some Rodents, +as the Agoutis, than of the rest of their own order. The best-known +species are _T. javanicus_, _T. napu_, _T. stanleyanus_, and _T. +memmina_. The first three are from the Malay Peninsula, or the islands of +the Indo-Malayan Archipelago, the last from Ceylon and India. A fossil +species occurs in the Pliocene of the latter country. + +_Dorcatherium_[192] is distinguished chiefly by the feet being stouter +and shorter, the outer toes better developed, and the two middle +metacarpals not ankylosed together. Its dental formula (as that of +_Tragulus_) is usually _i_ ⁰⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃ = 34. Vertebræ: +C 7, D 13, L 6, S 5, C 12-13. The only existing species, _D. aquaticum_ +(Fig. 118), from the west coast of Africa, is rather larger than any of +the Asiatic Chevrotains, which it otherwise much resembles, but it is +said to frequent the banks of streams, and have much the habits of Pigs. +It is of a rich brown colour, with back and sides spotted and striped +with white. It is evidently the survivor of a very ancient form, as +remains of the type species (_D. naui_), only differing in size, occur in +the lower Pliocene and Miocene of Europe; fossil species are also found +in the Indian Pliocene. In _D. naui_ there are, at least frequently, four +lower premolars, while the existing species has but three of these teeth. + +[Illustration: FIG. 118.—The African Water-Chevrotain (_Dorcatherium +aquaticum_).] + +_Extinct Traguloids._—A number of small selenodont Artiodactyles from +various Miocene and Pliocene deposits appear to connect the modern +Tragulina so closely with _Gelocus_ (p. 294), and thus with the ancestral +_Cervidæ_, that their classification is almost an impossibility. Thus +_Leptomeryx_, from the Miocene of the United States, is regarded as a +Traguloid, having four premolars in each jaw and with the metatarsals +fused into a cannon-bone. _Prodremotherium_, of the Upper Eocene +Phosphorites of France, differs in that the metacarpals also form a +cannon-bone; while in the American _Hypertragulus_, both metacarpals and +metatarsals remain separate. _Bachitherium_, of the French Phosphorites, +apparently presents affinity with _Gelocus_, _Prodremotherium_, and +_Dorcatherium_. In this genus the first of the four lower premolars +assumes the character and function of a canine, the true canine being +incisor-like, and there are traces of minute upper incisors. + + +PECORA, OR COTYLOPHORA. + +No premaxillary teeth or caniniform premolars. Upper canines generally +absent, though sometimes largely developed. Inferior incisors, three on +each side with an incisiform canine in contact with them. Molariform +teeth consisting of _p_ ³⁄₃, _m_ ³⁄₃, in continuous series. Auditory +bullæ simple and hollow within. Odontoid process in the form of a +crescent, hollow above. Distal extremity of the fibula represented by a +distinct malleolar bone of peculiar shape, articulating with the outer +surface of the lower end of the tibia. Third and fourth metacarpals and +metatarsals confluent. Outer or lateral toes small and rudimentary, or +in some cases entirely suppressed; their metapodial bones never complete +in existing forms. Navicular and cuboid bones of tarsus united. Horns or +antlers usually present, at least in the male sex. Left brachial artery +arising from a common innominate trunk, instead of coming off separately +from the aortic arch as in the preceding sections. Stomach with four +complete cavities. Placenta cotyledonous.[193] + +[Illustration: FIG. 119.—A shed right antler of the Red Deer (_Cervus +elaphus_), found in an Irish lake. _a_, Brow tine; _b_, bez tine; _c_, +tres tine; _d_, crown or royal tine. (After Owen.)] + +The Pecora or true Ruminants form at the present time an extremely +homogeneous group, one of the best-defined and most closely united of any +of the Mammalia. But, though the original or common type has never been +departed from in essentials, variation has been very active among them +within certain limits; and the great difficulty which all zoologists have +felt in subdividing them into natural minor groups arises from the fact +that the changes in different organs (feet, skull, frontal appendages, +teeth, cutaneous glands, etc.) have proceeded with such apparent +irregularity and absence of correlation that the different modifications +of these parts are most variously combined in different members of the +group. It appears, however, extremely probable that they soon branched +into two main types, represented in the present day by the _Cervidæ_ and +the _Bovidæ_,—otherwise the antlered and horned Ruminants. Intermediate +smaller branches produced the existing Musk-Deer and Giraffe, as well as +the extinct _Helladotherium_ inclining to the first-named group, and the +extinct _Sivatherium_, _Brahmatherium_, _Hydaspitherium_, and others more +allied to the latter, although upon the true relationship of these forms +there is a difference of opinion. + +[Illustration: FIG. 120.—Head of Deer (_Cervus schomburgki_), showing +antlers. From Sclater, _Proc. Zool. Soc._ 1877, p. 682.] + +The earliest forms of true Pecora, as _Palæomeryx_, generally had no +frontal appendages, and some few forms continue to the present day in a +similar case. In the very large majority, however, either in both sexes +or in the male only, a pair or occasionally two pairs (_Tetraceros_ and +the extinct _Sivatherium_) of processes are developed from the frontal +bones as weapons of offence and defence, these being almost always formed +on one or other of two types. + +1. “Antlers” are outgrowths of true bone, covered during their growth +with vascular, sensitive integument coated with short hair. When the +growth of the antler is complete, the supply of blood to it ceases, the +skin dies and peels off, leaving the bone bare and insensible, and after +a time, by a process of absorption near the base, it becomes detached +from the skull and is “shed” (Fig. 119). A more or less elongated portion +or “pedicle” always remains on the skull from the summit of which a new +antler is developed. In the greater number of existing species of Deer +this process is repeated with great regularity at the same period of each +year. The antler may be simple, straight, subcylindrical, tapering and +pointed, but more often it sends off one or more branches called “tines” +or “snags” (Fig. 119). In this case the main stem is termed the “beam.” +Commonly all the branches of the antler are cylindrical and gradually +tapering. Sometimes they are more or less expanded and flattened, the +antler being then said to be “palmated.” In young animals the antlers +are always small and simple, and in those species in which they are +variously branched or palmated, this condition is only gradually acquired +in several successive annual growths. An interesting parallel has been +observed here, as in so many other cases, between the development of the +race and that of the individual. Thus the earliest known forms of Deer, +those of the Lower Miocene, generally have no antlers, as in the young of +the existing species. The Deer of the Middle Miocene have simple antlers, +with not more than two branches, as in existing Deer of the second +year; but it is not until the Pliocene and Pleistocene times that Deer +occur with antlers developed with that luxuriance of growth and beauty +of form characteristic of some of the existing species in a perfectly +adult state. Among recent _Cervidæ_, antlers are wanting in the genera +_Moschus_ and _Hydropotes_; they are present in both sexes in _Tarandus_ +(the Reindeer), and in the male sex only in all others. + +In those forms with the most complex antlers (Figs. 119, 120) the tine +immediately over the forehead is termed the _brow tine_, the next one +the _bez tine_, and the third one the _tres tine_; the mass of points at +the summit of the antler being termed either the _royal_ and _surroyal +tines_, or collectively the _crown_. The nodulated bony ring at the base +of the antler, just above the point at which it separates from the +pedicle when it is shed, is termed the _burr_. + +[Illustration: FIG. 121.—Head of Antelope (_Gazella granti_), showing +horns. From Sir V. Brooke, _Proc. Zool. Soc._ 1878, p. 724.] + +2. The horns of the _Bovidæ_ consist of permanent, conical, usually +curved bony processes, into which air-cells continued from the frontal +sinuses often extend, called “horn-cores,” ensheathed in a case of +true horn, an epidermic development of fibrous structure, which grows +continuously, though slowly, from the base, and wears away at the apex, +but is very rarely shed entire. The only existing species in which +the latter process occurs regularly and periodically is the American +Prong-Buck (_Antilocapra_), in which the horns also differ from those of +all others in being bifurcated. Horns are not present at birth, but begin +to grow very soon afterwards. The males of all existing _Bovidæ_ possess +them, and they are also present (though usually not so fully developed) +in the females of all except the genera _Boselaphus_, _Strepsiceros_, +_Tragelaphus_, _Antilope_, _Æpyceros_, _Saiga_, _Cobus_, _Cervicapra_, +_Pelea_, _Nanotragus_, _Neotragus_, _Cephalophus_, and _Tetraceros_; as +well as in some species of _Gazella_, such as _G. picticandata_ and _G. +walleri_. + +[Illustration: FIG. 122.—Crown surface of a worn left upper molar +of _Palæomeryx sivalensis_, to show brachydont type. (From the +_Palæontologia Indica_.)] + +Another character by which different members of the _Pecora_ can be +distinguished among themselves is derived from the nature of the molar +teeth. Although there is nothing in the general mode and arrangement of +the enamel-folds, or in the accessory columns, absolutely distinctive +between the two principal families, existing species may generally be +distinguished, inasmuch as the true molars of the _Cervidæ_ are more or +less brachydont, and those of the _Bovidæ_ generally hypsodont, _i.e._, +the teeth of the former have comparatively short crowns (Fig. 122), +which, as in most mammals, take their place at once with the neck (or +point where the crown and root join) on a level with or a little above +the alveolar border, and remain in this position throughout the animal’s +life; whereas in the other forms (Fig. 123), the crown being lengthened +and the root small, the neck does not come up to the alveolar level +until a considerable part of the surface has worn away, and the crown +of the tooth thus appears for the greater part of the animal’s life +partially buried in the socket. In this form of tooth (which is almost +always most developed in the posterior molars of the permanent series) +the constituent columns of the crown are necessarily nearly parallel, +whereas in the first-described they diverge from the neck towards the +free or grinding surface of the tooth. In the completely hypsodont form +the interstices of the lengthened columnar folds of enamel and dentine +are filled up with cement, which gives stability to the whole organ, +and is entirely or nearly wanting in the short-crowned teeth. The same +modification from low to high crowns without essential alteration of +pattern is seen in an even still more marked manner in some of the +Perissodactyle Ungulates, the tooth of the Horse bearing to that of +_Anchitherium_ the same relation as that of an Ox does to the early +selenodont Artiodactyles. A parallel modification has also taken place in +the molar teeth of the Proboscidea. + +[Illustration: FIG. 123.—Inner and outer aspects of an almost unworn left +upper molar of the Nilghai (_Boselaphus tragocamelus_), to show hypsodont +type. (From the _Palæontologia Indica_.)] + +As the hypsodont tooth is essentially a modification of, and, as it were, +an improvement upon, the brachydont, it is but natural to expect that +all intermediate forms may be met with. Even among the Deer themselves, +as pointed out by Lartet, the most ancient have very short molars, and +the depressions on the grinding surface are so shallow that the bottom +is always visible; while in the _Cervidæ_ of the more recent Tertiary +periods, and especially the Pleistocene and living species, these same +cavities are so deep that whatever be the state of the dentition the +bottom cannot be seen. Some existing Deer, as the Axis, are far more +hypsodont than the majority of the family; and, on the other hand, +many of the Antelopes (as _Tragelaphus_) retain much of the brachydont +character, which is, however, completely lost in the more modern and +highly specialised Sheep and Oxen. + +[Illustration: FIG. 124.—Stomach of Ruminant opened to show internal +structure. _a_, Œsophagus; _b_, rumen or paunch; _c_, reticulum or +honey-comb bag; _d_, psalterium or manyplies; _e_, abomasum or reed; _f_, +duodenum.] + +The complicated stomach of the Pecora (Fig. 124), which is necessary for +the performance of the peculiar function known as “chewing the cud”—a +function common also to the Tragulina and Tylopoda—is divided into four +well-defined compartments, known as (1) the Rumen or Paunch, (2) the +Reticulum or Honey-comb Bag, (3) the Psalterium or Manyplies, (4) the +Abomasum or Reed. The paunch is a very capacious receptacle, shaped +like a blunted cone bent partly upon itself. Into its broader base +opens the œsophagus or gullet at a spot not far removed from its wide +orifice of communication with the second stomach or honey-comb bag. Its +inner walls are nearly uniformly covered with a pale mucous membrane, +which is beset with innumerable close-set, short, and slender villi, +resembling very much the “pile” on velvet. The honey-comb bag is very +much smaller than the paunch. It is nearly globose in shape, and receives +its name on account of the peculiar arrangement of its mucous membrane +which forms shallow hexagonal cells all over its inner surface. Running +along its upper wall there is a deep groove, coursing from the first to +the third stomach. This groove plays an important part in the act of +rumination. Its walls are muscular, like those of the viscus with which +it is associated, which allows its calibre to be altered. Sometimes it +completely closes round so as to become converted into a tube by the +opposition of its edges. At others it forms an open canal. The manyplies +is globular in form, and its lining membrane is raised into longitudinal +folds or laminæ arranged very much like the leaves of a book, and very +close together. Their surfaces are roughened by the presence of small +projections or papillæ. The reed is the proper digestive stomach, +corresponding with the same organ in man. Its shape is somewhat pyriform, +and its walls are formed of a smooth mucous membrane, which secretes the +gastric juice. + +When the food is first swallowed it is conveyed into the paunch, and +after undergoing a softening process there it is regurgitated into +the mouth, and undergoes a further trituration by the molar teeth and +mixture with the secretion of the salivary and buccal glands. It is then +swallowed again, but now passes directly through the before-mentioned +groove into the manyplies, and, after filtering through the numerous +folds of the lining membrane of this cavity, finally reaches the fourth +or digestive stomach. + +The placenta of the Pecora is characterised by the fœtal villi being +collected into groups or cotyledons, which may present either a convex +or a concave surface to the uterus. These cotyledons are received into +permanent elevations in the mucous membrane of the uterus, the surfaces +of which present a curvature which is the reverse of the cotyledons. + + +_Family_ CERVIDÆ. + +Frontal appendages, when present, in the form of antlers. First molar, +at least, in both jaws brachydont. Two orifices to the lachrymal duct, +situated on or inside the rim of the orbit. An antorbital or lachrymal +vacuity of such dimensions as to exclude the lachrymal bone from +articulation with the nasal. Upper canines usually present in both +sexes and sometimes attaining a very great size in the male (see Fig. +134). Lateral digits of both fore and hind feet, almost always present, +and frequently the distal ends of the metapodials. Placenta with few +cotyledons. Gall-bladder absent (except in _Moschus_). This family +contains numerous species, having a wide geographical distribution, +ranging in the New World from the Arctic Circle as far south as Chili, +and in the Old World throughout the whole of Europe and Asia, though +absent in the Ethiopian and Australian regions. + +It may be divided into two subfamilies. + +Subfamily =Moschinæ=.—This subfamily is represented solely by the +Musk-Deer, which differs so remarkably from the true Deer that it is +considered by several writers as the representative of a separate family. +The late Professor Garrod even suggested that it should be regarded as an +extremely aberrant member of the _Bovidæ_. + +[Illustration: FIG. 125.—The Musk-Deer (_Moschus moschiferus_).] + +_Moschus._[194]—The Musk-Deer (Fig. 125) in many respects stands by +itself as an isolated zoological form, retaining characters belonging +to the older and more generalised types of ruminants before they were +distinctly separated into the horned and the antlered sections now +dominant upon the earth. One of these characters is that both sexes are +entirely devoid of any sort of frontal appendage. In this, however, +it agrees with one existing genus of true Deer (_Hydropotes_); and, +as in that animal, the upper canine teeth of the males are remarkably +developed, long, slender, sharp pointed, and gently curved, projecting +downwards out of the mouth with the ends turned somewhat backwards. +Vertebræ: C 7, D 14, L 5, S 5, C 6. Among the anatomical peculiarities in +which it differs from all true Deer and agrees with the _Bovidæ_ is the +presence of a gall-bladder. The hemispheres of the brain are but slightly +convoluted, and the cotyledons of the placenta are arranged in a peculiar +linear manner.[195] + +Although, owing to variations of colour presented by different +individuals in different localities and seasons, several nominal species +have been described, zoologists are now generally agreed that there is +but one, the _Moschus moschiferus_ of Linnæus. In size it is rather +less than the European Roe Deer, being about 20 inches high at the +shoulder. Its limbs, especially the hinder ones, are long. The feet are +remarkable for the great development of the lateral pair of hoofs, and +for the freedom of motion they all present, so that they appear to have +the power of grasping projecting rocky points,—a power which must be +of great assistance to the animal in steadying it in its agile bounds +among the crags of its native haunts. The ears are large, and the tail +quite rudimentary. The hair covering the body is long, coarse, and of a +peculiarly brittle and pith-like character, breaking with the application +of an extremely slight force; it is generally of a grayish-brown colour, +sometimes inclined to yellowish-red, and often variegated with lighter +patches. The Musk-Deer has a wide distribution over the highlands +of central and eastern Asia, including the greater part of southern +Siberia, and extends to Kashmir on the south-west and Cochin-China on +the south-east, always, however, at considerable elevations,—being +rarely found in summer below 7000 feet above the sea-level, and ranging +as high as the limits of the thickets of birch or pines, among which +it mostly conceals itself in the daytime. It is a hardy, solitary, and +retiring animal, chiefly nocturnal in its habits, and almost always found +alone, rarely in pairs, and never in herds. It is exceedingly active +and sure-footed, having few equals in traversing rocky and precipitous +ground; and it feeds on moss, grass, and leaves of the plants which grow +on the mountains among which it makes its home. + +Most of the animals of the group to which the Musk-Deer belongs, in +fact the large majority of mammals, have some portion of the cutaneous +surface peculiarly modified and provided with glands secreting some +odorous and oleaginous substance specially characteristic of the species. +This, correlated with the extraordinary development of the olfactory +organs, appears to offer the principal means by which animals in a +state of nature become aware of the presence of other individuals of +their own species, or of those inimical to them, even at very great +distances, and hence it is of extreme importance both to the well-being +of the individual and to the continuance of the race. The situation of +this specially modified portion of skin is extremely various, sometimes +between the toes, as in Sheep, sometimes on the face in front of the +eyes, as in many Deer and Antelopes. Sometimes it is in the form of a +simple depression or shallow recess, often very deeply involuted, and in +its fullest state of development it forms a distinct pouch or sac with +a narrow tubular orifice. In this sac a considerable quantity of the +secretion can accumulate until discharged by the action of a compressor +muscle which surrounds it. This is the form taken by the special gland of +the Musk-Deer, which has made the animal so well known, and has proved +the cause of an unremitting persecution to its possessor. It is found +in the male only, and is a sac about the size of a very small orange, +situated beneath the skin of the abdomen, the orifice being immediately +in front of the preputial aperture. The secretion with which the sac is +filled is of dark-brown or chocolate colour, and when fresh described as +being of the consistence of “moist gingerbread,” but becoming dry and +granular after keeping. It has a peculiar and very powerful scent, which +when properly diluted and treated forms the basis of many of our most +admired perfumes. When the animal is killed the whole gland or “pod” is +cut out and dried, and in this form reaches the market of the Western +World, chiefly through China. + +Subfamily =Cervinæ.=—This subfamily includes all the true Deer. According +to the arrangement proposed by Sir V. Brooke[196] the existing _Cervinæ_ +may be divided into the sections Plesiometacarpalia and Telemetacarpalia. + +=Plesiometacarpalia.=—In this section, which is mainly characteristic of +the Old World, the proximal portions of the lateral (second and fifth) +metacarpals persist, and the vomer is never so ossified as to divide the +posterior osseous nares into two distinct passages. The premaxillæ nearly +always articulate with the nasals. + +_Cervulus._[197]—Antlers half the length of the head, placed on pedicles +nearly equal to them in length. Brow tine short, inclined inwards and +upwards; terminal extremity of beam unbranched, and curved downwards and +inwards. Lachrymal fossa of skull very large, and extending into facial +part of jugal; lachrymal (antorbital) vacuity moderate. Ascending portion +of premaxillæ at least as long as nasals. A permanent ridge extending +from each pedicle over the orbit, lachrymal fossa and vacuity. Auditory +bulla much inflated. Upper canines of males very large. Ectocuneiform +united with naviculo-cuboid of tarsus. No traces of the phalanges of the +lateral digits. + +The native name Muntjac has been generally adopted in European languages +for a small group of Deer indigenous to the southern and eastern parts +of Asia and the adjacent islands, which are separated by very marked +characters from all their allies. They are also called “Kijang” or +“Kidjang,” and constitute the genus _Cervulus_ of Blainville and most +zoologists;—_Styloceros_ of Hamilton-Smith, and _Prox_ of Ogilby. They +are all of small size compared with the majority of Deer, and have long +bodies and rather short limbs and neck. The antlers, which as in most +Deer are present in the male only, are small and simple, and the main +stem or beam, after giving off a very short brow tine, inclines backwards +and upwards, is unbranched and pointed, and when fully developed curves +inwards and somewhat downwards at the tip. These small antlers are +supported upon pedicles or permanent processes of the frontal bones, +longer than in any other Deer, and the front edges of which are continued +downwards as strong ridges passing along the sides of the face above the +orbits, and serving to protect the large supraorbital glands lying on +their inner sides. The lachrymal fossa of the skull, in which is lodged +the large suborbital gland or crumen, is of great depth and extent. The +upper canine teeth of the males are strongly developed and sharp, curving +downwards, backwards, and outwards, projecting visibly outside the mouth +as tusks, and loosely implanted in their sockets. In the females they are +very much smaller. The limbs exhibit several structural peculiarities +not found in other Deer. The lateral digits of both fore and hind feet +are very little developed, the hoofs alone being present and their bony +supports (found in all other Deer) wanting. There is a tufted gland on +the outer side of the metatarsus. + +The Muntjacs are solitary animals, very rarely even two being seen +together. They are fond of hilly ground covered with forests, in the +dense thickets of which they pass most of their time, only coming to +the skirts of the woods at morning and evening to graze. They carry the +head and neck low and the hind-quarters high, their action in running +being peculiar and not very elegant, somewhat resembling the pace of a +sheep. Though with no power of sustained speed or extensive leap, they +are remarkable for flexibility of body and facility of creeping through +tangled underwood. They are often called by Indian sportsmen “Barking +Deer,” a name given on account of their alarm cry, a kind of short shrill +bark, like that of a fox but louder, which may often be heard in the +jungles they frequent both by day and by night. When attacked by dogs the +males use their sharp canine teeth with great vigour, inflicting upon +their opponents deep and even dangerous wounds. + +There is some difference of opinion among zoologists as to the number of +species of the genus _Cervulus_. Sir Victor Brooke, who investigated this +question in 1878 (see _Proceedings of the Zoological Society of London_ +for that year, p. 898), came to the conclusion that there are certainly +three which are quite well marked, viz.— + +_C. muntjac_ (Fig. 126), found in British India, Burma, the Malay +Peninsula, Sumatra, Java, Hainan, Banca, and Borneo. The general colour +is a bright yellowish-red, darker in the upper parts of the back; the +fore legs from the shoulder downwards and the lower part of the hind +legs, dark bluish-brown; anterior parts of the face from the muzzle to +between the eyes, brown—a blackish line running up the inside of each +frontal ridge; chin, throat, inside of hind legs, and under surface of +tail white. The female has a black bristly tuft of hair on the spot from +which the pedicles of the antlers of the male grow. The average length +of the male, according to Jerdon, is 3½ feet, tail 7 inches, height 26 +to 28 inches. The female is a little smaller. The specimens from Java, +Sumatra, and Borneo are of larger size than those from the mainland, and +may possibly be of distinct species or race. + +[Illustration: FIG. 126.—The Muntjac (_Cervulus muntjac_).] + +_C. lacrymans_ of Milne-Edwards, or Sclater’s Muntjac of Swinhoe, from +Moupin, and near Hangchow, China. + +_C. reevesi_, a very small species from southern China. + +Subsequently the name _C. crinifrons_ has been applied to a Muntjac +from Ningpo, China, readily distinguished from all other species by its +bushy forehead and long tail. Another species from Tenasserim has been +described as _C. feæ_. + +Small Deer from the European Pliocene have been provisionally referred +to _Cervulus_, but the so-called _Prox furcatus_, of the Miocene, is now +included in _Palæomeryx_. + +_Elaphodus._[198]—Antlers very small, unbranched, supported on long, +slender, converging pedicles. Ascending rami of premaxillæ shorter than +nasals. No supraorbital ridges or frontal glands. Upper canines of male +long, but not everted. A distinct frontal tuft of hair. Other characters +as in _Cervulus_. + +This genus (which has also received the name of _Lophotragus_) is +represented by a small Deer (Fig. 127) from China of about the same +size as the Indian Muntjac. The male has minute simple antlers and very +large canine teeth. There are no supraorbital glands, nor is there a +tufted gland on the metatarsus. The limbs have the same peculiarities +as in _Cervulus_, but the mesocuneiform may also ankylose with the +ectocuneiform, and traces of the metacarpals may remain. The hair is +coarse and somewhat quill-like. + +[Illustration: FIG. 127.—Male of _Elaphodus michianus_. From Sclater +_Proc. Zool. Soc._ 1876, p. 273.] + +_Cervus._[199]—The great majority of the Deer of the Old World may be +included in this large genus, which is one not easy of definition. The +antlers of the male are, however, large, and two or three times the +length of the head, and may be either rounded or palmate; the canines are +never large; the ectocuneiform of the tarsus remains distinct from the +naviculo-cuboid; the lateral digits are represented by their phalanges; +and the skull does not carry prominent frontal ridges. Vertebræ: C 7, D +13, L 6, S 4, C 11-14. The size of the lachrymal fossa and vacuity, and +the degree of inflation of the auditory bulla, are subject to variation +in the different groups into which the genus may be divided. + +The _Rusine_ group is characteristic of the Oriental region, where it is +typically represented by the Sambur (_C. aristotelis_) of India, Burma, +and China. The antlers are rounded, and often strongly grooved, without a +bez tine, and with the beam simply forked at the extremity, upright, and +but slightly curved; the angle formed by the brow tine, which rises close +to the burr, being acute. The molars are markedly hypsodont, with small +accessory columns. The lachrymal fossa is deep and the vacuity large; the +auditory bulla is slightly inflated and rugose. Tail moderate; neck maned. + +The Sambur, which is abundant in hilly districts, is a fine animal, +standing nearly 5 feet in height, and of massive build; the general +colour being deep brown. _C. equinus_, of Borneo, Sumatra, and Singapore, +_C. swinhoei_, of Formosa, _C. philippinus_, and _C. alfredi_ of the +Philippines, are closely allied species, of which the two latter are +of smaller dimensions. The Indian Hog Deer (_C. porcinus_) is a still +smaller form, not larger than the Roe. _C. hippelaphus_ of Java, _C. +timoriensis_, and _C. moluccensis_ are distinguished by the posterior +branch of the beam of the antler being considerably larger than the +anterior. + +The _Rucervine_ group is another strictly Oriental one, and is +represented by the Swamp Deer (_C. duvaucelli_) of India, the closely +allied _C. schomburgki_ of Siam, of which the antlers are shown in Fig. +119 (p. 309), and _C. eldi_ of Burma and Hainan. The beam of the antler +is somewhat flattened, and more curved than in the Rusine group; the +large brow tine is given off from the beam at an obtuse angle and curves +upwards; the beam bifurcates into two branches, which again divide. Skull +as in the Rusine group, but relatively narrower. Tail short; neck maned. + +The Swamp Deer is somewhat smaller than the Sambur, and of a full +yellowish colour. Fossil representatives of this group occur in the +Pliocene of India. + +The _Elaphurine_ group is represented only by the very aberrant _C. +davidianus_ of Northern China. In size and proportions this species +approximates to the Swamp Deer, but the antlers are peculiar in rising +straight from the brow and then giving off a long and straight back tine +(correlated by Sir V. Brooke with the posterior branch of the Rusine +antler); the summit of the beam is forked, and in old individuals the +two tines of the fork may again branch. Nasals long, and much expanded +between the lachrymal vacuities, of which they form the inner border; +lachrymal fossa large and deep. Tail long; neck maned. + +The _Axine_ group includes only the well-known Axis of India, readily +distinguished by the white spots with which the body is marked. Antlers +of a Rusine type, the beam being much curved, and the brow tine usually +given off at an acute or right angle. Molars very hypsodont. The +coloration of the Axis is more brilliant than that of any other member of +the family. + +Here may be noticed a group of Deer mainly characteristic of the +eastern Palæarctic region, frequently known as the _Pseudaxine_ group, +which appears to connect the Axine with the Elaphine type. Well-known +representatives of this group are _C. sika_ (Fig. 128) of Japan, _C. +mantchuricus_ of China, and _C. taëvanus_ of Formosa. The antlers have a +brow and tres tine, and then a forked beam, of which the posterior tine +is the smaller. The lachrymal vacuity and fossa are of moderate size; +and the auditory bulla is only moderately inflated, and quite smooth +externally. Tail moderate; neck maned. In summer the coat is spotted, but +is plain in winter. A herd of _C. sika_ have been acclimatised in Ireland +by Viscount Powerscourt, at Powerscourt, County Wicklow. A number of Deer +from the Pliocene of Europe, such as _C. perrieri_ and _C. etueriarum_, +appear to be allied both to the Pseudaxine and Axine groups. + +[Illustration: FIG. 128.—The Japanese Deer (_Cervus sika_). From Lord +Powerscourt, _Proc. Zool. Soc._ 1884, p. 209.] + +The _Elaphine_ or typical group is at once characterised by the presence +of a bez tine to the antlers (Fig. 129), in which the beam is rounded, +and splits up near the summit into a larger or smaller number of snags, +often arranged in a cup-like manner. Skull as in the preceding group. All +the species large. The Red Deer, _C. elaphus_, which is dark brown in +colour, with a light patch on the rump, inhabits Europe, Western Asia, +and Northern Africa—the so-called Barbary Deer not being specifically +distinct. A full-grown Scotch Stag is fully 4 feet in height at the +withers. The antlers are shed between the end of February and the early +part of April; old animals shedding earlier than younger ones. The young, +which (as in all the members of the genus except some of the Rusine +species) are spotted, are born at the end of May or the beginning of +June. The points on the antlers increase in number with the age of the +creature, and when twelve are present it is known in Scotland as a “royal +stag.” This number, however, is sometimes exceeded, as in the case of a +pair of antlers, weighing 74 lbs., from a stag killed in Transylvania, +which had forty-five points. The antlers during the second year consist +of a simple unbranched stem, to which a tine or branch is added in each +succeeding year, until the normal development is attained, after which +their growth is somewhat irregular. Many of the antlers dug up in British +peat-beds (as Fig. 118) are larger than those of living individuals, +and in the cave-deposits of England and the Continent antlers are met +with rivalling those of the Wapiti in size; these large fossil antlers +probably indicating the ancestral form from which the Red Deer and +several of the allied species are descended. + +[Illustration: FIG. 129.—Head of the Wapiti (_Cervus canadensis_).] + +The North American Wapiti (_Cervus canadensis_, Fig. 129), the Persian +Maral (_C. maral_), the Kashmir Stag (_C. cashmeerianus_), as well as +_C. affinis_ of Tibet, are all closely allied to the Red Deer, but are +of larger size, this being especially the case with the first two. A +fine example of the antlers of the Wapiti is shown in the accompanying +woodcut, and exhibits the absence of a cup at the surroyals, by which +this species is distinguished from the Red Deer. + +The last, or _Damine_ group of existing Deer includes the Common and the +Persian Fallow Deer. These are readily characterised by the palmation +of the antlers in the region of the surroyals and the spotted coat. +The Common Fallow Deer (_C. dama_) stands about three feet in height. +The Persian Fallow Deer (_C. mesopotamicus_) is very closely allied, +differing only in its slightly larger size and the form of the antlers, +the two breeding together. The common species, although now kept in +English parks, does not appear to be a native of this country, having +probably been introduced from the regions bordering the Mediterranean. +The fur is of a yellowish-brown colour (whence the name “fallow”), marked +with white spots; there is, however, a uniformly dark brown variety found +in Britain. The bucks and does live apart, except during the pairing +season; and the doe produces one or two, and sometimes three fawns at +a birth. The Fallow Deer from the Pleistocene and Pliocene deposits +of the East Coast described under the names of _C. browni_ and _C. +falconeri_ appear to have been closely allied to the existing species. +The remarkable _C. verticornis_, of the Norfolk Forest-bed, is regarded +as an aberrant member of this group, in which the antlers are very short +and thick, with the brow tine cylindrical and downwardly curved, and the +beam expanded above the tres tine into a crown with two points. + +The extinct Irish Deer (_Cervus giganteus_), of which the skeleton is +shown in the woodcut (Fig. 130), is the only representative of the +_Megacerotine_ group. The antlers, which may have a span of over 11 +feet, are enormously palmated, and have a bifurcated brow tine, a small +bez tine, and a third posterior tine. The skeleton measures upwards of +6 feet at the withers. Remains of this species are especially common in +the peat-bogs of Ireland, but are also met with in Pleistocene deposits +over a large part of Europe. In addition to the forms already mentioned +there are many other fossil species of _Cervus_, some of which, like the +English Pleistocene _C. sedgewicki_, cannot be included in any of the +existing groups. There is no conclusive evidence of the existence of any +species of _Cervus_ before the Lower Pliocene period. + +=Telemetacarpalia.=—This section includes all the Deer of the New World, +together with some Old World forms, and is characterised by retaining the +distal extremities of the lateral (second and fifth) metacarpals. With +the exception of _Alces_, _Capreolus_, and _Hydropotes_ (which are either +partly or entirely Old World types), the vomer is so much ossified as to +divide the posterior bony nares into two distinct orifices (Fig. 132). + +[Illustration: FIG. 130.—Skeleton of the Gigantic Irish Deer (_Cervus +giganteus_). After Owen.] + +_Rangifer._[200]—The Reindeer, or Caribou as it is termed in North +America, is the sole representative of the genus _Rangifer_, which is +sufficiently distinguished from all its allies by the presence of antlers +in both sexes. The lachrymal vacuity is small. This animal is distributed +over the northern parts of Europe, Asia, and America; the differences +which may be observable in specimens from different regions not being +sufficient to allow of specific distinction. The Reindeer is a heavily +built animal, with short limbs, in which the lateral hoofs are well +developed, and the cleft between the two main hoofs is very deep, so that +these hoofs spread out as the animal traverses the snow-clad regions in +which it dwells. The antlers (Fig. 131) are of very large relative size. +There is a bez as well as a brow tine, which are peculiar in being either +branched or palmated. In the American race (Caribou), as well as in some +of the specimens found fossil in the English Pleistocene (Fig. 131), one +of the brow tines is generally aborted to allow of the great development +of the other. The dentition of the Reindeer is frequently remarkable +for the very small size of the posterior lobe of the last lower molar. +Vertebræ: C 7, D 14, L 5, S 5, C 11. + +[Illustration: FIG. 131.—Skull and antlers of the Reindeer (_Rangifer +tarandus_), from an English Pleistocene deposit. _br_, Brow tine; _bz_, +bez tine. (After Owen.)] + +The Reindeer has long been domesticated in Scandinavia, and is of +especial value to the Laplanders, whom it serves as a substitute for +the Horse, Cow, Sheep, and Goat. It is capable of drawing a weight of +300 lbs., and its fleetness and endurance are remarkable. Harnessed to +a sledge it will travel without difficulty 100 miles a day over the +frozen snow, on which its broad and deeply cleft hoofs are admirably +adapted for travelling. During the summer the Lapland Reindeer feeds +chiefly on the young shoots of the willow and birch; and since at this +season migration to the coast seems necessary to the well-being of this +animal, the Laplander, with his herds, sojourns for several months in +the neighbourhood of the sea. In winter its food consists chiefly of the +so-called reindeer-moss and other lichens which the animal makes use +of its hoofs in seeking for beneath the snow. The wild Reindeer grows +to a much greater size than the tame breed; but in Northern Europe the +former are being gradually reduced through the natives entrapping and +domesticating them. The tame breed found in Northern Asia is much larger +than the Lapland form, and is there used to ride on. Remains referable +to the existing species are found in the cavern and other Pleistocene +deposits of Europe. + +[Illustration: FIG. 132.—Hinder part of the base of the cranium of the +Virginian Deer (_Cariacus virginianus_). From Garrod, _Proc. Zool. Soc._ +1877, p. 13.] + +_Alces._[201]—The Elk or Moose (_Alces machlis_) has the same general +distribution as the Reindeer, and is likewise the single existing +representative of its genus. It is the largest existing member of the +family, attaining sometimes a height of 8 feet at the withers. The +antlers (Fig. 133) have neither brow nor bez tine, but form an enormous +basin-shaped palmation, primarily composed of an anterior and a posterior +branch; their weight may be as much as 60 lbs. The nasal bones are very +short, and the narial aperture of great size. The Elk is covered with a +thick coarse fur of a brownish colour, longest on the neck and throat. +Its legs are long and its neck short, and as it is thus unable to feed +close to the ground, it browses on the tops of low plants, the leaves of +trees, and the tender shoots of the willow and birch. Its antlers attain +their full length by the fifth year, but in after years they increase in +breadth and in the number of snags, until fourteen of these are produced. +Although spending a large part of their lives in forests, Elks do not +suffer much inconvenience from the great expanse of their antlers, as in +making their way among trees they are carried horizontally to prevent +entanglement with the branches. Their usual pace is a shambling trot, but +when frightened they break into a gallop. The natural timidity of the +Elk forsakes the male at the rutting season, and he will then attack +whatever animal comes in his way. The antlers and hoofs are his principal +weapons, and with a single blow from the latter he has been known to kill +a wolf. The female often gives birth to two fawns, and with these she +retires into the deepest recesses of the forest, the young remaining with +her till their third year. The Elk ranges, but in scanty numbers, over +the whole of Northern Europe and Asia, as far south as East Prussia, the +Caucasus, and North China, and over North America from the New England +States westward to British Columbia. Fossil species are found in the +Pleistocene deposits of Europe. + +_Cervalces._[202]—A remarkable extinct Deer from the Pleistocene of North +America, described as _Cervalces_, appears in some respects (although +a true Telemetacarpalian) to connect _Alces_ with _Cervus_. Thus the +palmated antlers are divided into anterior and posterior branches, but +below this division there are two tines apparently corresponding to the +bez and posterior tines of _Cervus giganteus_ (Fig. 130). + +[Illustration: FIG. 133.—Head of Elk (_Alces machlis_).] + +_Capreolus._[203]—Antlers (in the existing species) less than twice the +length of the head, usually with three tines on each. Brow tine developed +from the anterior surface of the upper half of the antler, and directed +upwards. Lachrymal vacuity small. Premaxillæ not always articulating with +nasals. Auditory bullæ slightly inflated, rugose externally. Vertebræ: C +7, D 13, L 6, S 6, C 8. Tail very short. Glands in fore feet rudimentary; +large in hind feet. + +The Roe, or Roe Deer (_Capreolus caprea_), is a small form distributed +over Europe and Western Asia, being one of the species found in the +British Isles. The male is somewhat over two feet in height at the +withers, of a dark reddish-brown colour in summer, with a white patch +on the rump. The small antlers are approximated at their bases, and +consist of a rugged beam rising vertically for some distance, then +bifurcating, and the posterior branch again dividing. The Roe dates from +the Pleistocene period. Extinct Deer from the Continental Pliocene have +been provisionally referred to _Capreolus_. + +_Hydropotes._[204]—No antlers in either sex. Lachrymal fossa deep and +short (Fig. 134); lachrymal vacuity of moderate size. Orbits small and +but slightly prominent. Auditory bulla much inflated. Angle of mandible +much produced backwardly (Fig. 134); alveolar margins of mandible in +diastema sharp and everted. Canines of male very large, and slightly +convergent. Vertebræ: C 7, D 12, L 6, S 4, C 10. No tufts on metatarsals. +Foot glands small in fore feet, deep in hind ones. + +[Illustration: FIG. 134.—The left lateral view of the skull of a male +Chinese Water Deer (_Hydropotes inermis_), with the wall of the maxilla +cut away to show the root of the canine. ½ natural size. (From Sir V. +Brooke, _Proc. Zool. Soc._ 1872, p. 524.)] + +[Illustration: FIG. 135.—Upper surface of the brain of _Hydropotes +inermis_. (From Garrod, _Proc. Zool. Soc._ 1877, p. 792.)] + +The Chinese Water Deer (_H. inermis_) is the sole representative of this +genus. In the absence of antlers and the large canines of the male it +resembles _Moschus_, although very different in other respects. Thus +the brain (Fig. 135) has the hemispheres much convoluted, as in other +_Cervinæ_, and approximates to that of _Pudua_; while the placenta +and viscera likewise agree with those of the true Deer. In the total +absence of any ossification of the vomer to divide the posterior nares +_Hydropotes_ resembles _Capreolus_ and differs from all the following +genera. The Chinese Water-Deer is nearly of the same size as the Indian +Muntjac. It has short legs and a long body, the hair covering the latter +being of a light reddish-brown. It is a remarkably prolific animal, +differing from all other Deer in producing five or six young at a time. + +The mandible of a ruminant from the Middle Miocene of Gers in France, +described under the name of _Platyprosopus_, presents such a marked +resemblance to _Hydropotes_ in the form of the angle as to suggest a more +or less intimate affinity. + +_Cariacus._[205]—Skull (Fig. 132) with the vomer dividing the posterior +nares into two distinct chambers; premaxillæ not reaching nasals. Antlers +never greatly exceeding the length of the head. Lachrymal vacuity very +large, and lachrymal fossa small. Auditory bullæ slightly inflated. +Vertebræ: C 7, D 13, L 6, S 4, C 13. Tail long or short. Colour uniform +in adult. + +This genus, which agrees with the Reindeer in the division of the +posterior nares by the ossified vomer, comprises a number of species +confined to the New World, none of which attain very large dimensions, +and the antlers of which are relatively smaller than in the existing +species of _Cervus_. The genus may be divided into groups. + +The typical _Cariacine_ group, as represented by _C. virginianus_, has +well-developed antlers, with a short brow tine rising from the inner side +of the beam, and directed upwards, and several branches; a long tail; and +no upper canines. In this species, as well as in _C. mexicanus_ and other +forms, the antlers do not divide dichotomously, and the lachrymal fossa +is of moderate depth. The Mule Deer (_C. macrotis_) of North America is +distinguished by the dichotomous branching of the antlers and the deeper +lachrymal fossa. The Virginian Deer is somewhat smaller than the Fallow +Deer, and of a uniform reddish-yellow colour in summer, and light gray in +winter. + +The _Blastocerine_ group of South America is represented by _C. +paludosus_ and _C. campestris_, and has dichotomous antlers, with no +brow tine, and the posterior branch the larger, a short tail, and no +upper canines. The _Furciferine_ group includes _C. chilensis_ and +_C. antisiensis_, confined to western South America. The antlers are +not longer than the head, with a large anterior tine curving forwards +at right angles to the simple posterior one. Auditory bullæ slightly +inflated, and rugose. Upper canines may be present. The species are of +medium size. _C. clavatus_, of Central America, while resembling this +group in the characters of the skull and the arrangement of the hair on +the face, agrees with the next one in having simple spike-like antlers. + +The South American _Coassine_ group comprises the small forms known as +Brockets, in which the antlers form simple spikes not exceeding half the +length of the head. Some six species are known. + +Remains of _Cariacus_, mostly or entirely referable to existing species, +are of common occurrence in the Brazilian cave-deposits. _Blastomeryx_, +of the Pliocene of North America, is believed to be an allied type. + +_Pudua._[206]—Antlers in the form of minute simple spikes. Distinguished +from the Coassine group of _Cariacus_ by the articulation of the +premaxillæ with the nasals (as in the _Furciferine_ group), and the +coalescence of the ectocuneiform with the naviculo-cuboid, as well as by +various external characters. No upper canines. Represented only by the +very small _P. humilis_ of the Chilian Andes. + +_Extinct Genera._—In the European and other Tertiary deposits several +genera of extinct _Cervidæ_ occur, of which the more important may +be briefly mentioned. _Amphitragulus_, of the Lower Miocene of the +Continent, has four lower premolars, brachydont molars, and no antlers; +the largest species being somewhat bigger than the Musk-Deer. The closely +allied _Palæomeryx_ (_Dremotherium_ or _Micromeryx_) generally has but +three lower premolars, and the brachydont upper molars (Fig. 122), like +those of _Amphitragulus_, want the small accessory inner column[207] +found in modern Deer. In _P. feignouxi_, of the Lower Miocene, the +lateral metacarpals, although slender, were complete, and the males had +large canines, but no antlers. _P. furcatus_, of the Middle Miocene, had +small antlers, and the canines appear to have been reduced in size. This +genus, besides being represented in the European Miocene, also occurs in +the Pliocene of India and China; some of the species being as large as +the Red Deer. + + +_Family_ GIRAFFIDÆ. + +In the existing genus the frontal appendages consist of a pair of +short, erect, permanent bony processes placed over the union of the +frontal and the parietal bones, ossified from distinct centres, though +afterwards ankylosed to the skull, covered externally with a hairy +skin, present in both sexes, and even in the new-born animal. Anterior +to these is a median protuberance on the frontal and contiguous parts +of the nasal bones, which increases with age, and is sometimes spoken +of as a third horn. Skull with a lachrymal vacuity. No upper canines. +Molars brachydont, with rugose enamel; the upper ones having no inner +accessory column. Lateral digits entirely absent on both fore and hind +feet, even the hoofs not developed. Humerus with double bicipital groove. +Vertebræ: C 7, D 14, L 5, S 3, C 20. Gall-bladder generally absent. Male +reproductive organs and placenta of a Bovine type. Dentition: _i_ ⁰⁄₃, +_c_ ⁰⁄₁, _p_ ³⁄₃, _m_ ³⁄₃. + +[Illustration: FIG. 136.—The Giraffe (_Giraffa camelopardalis_).] + +_Giraffa._[208]—The Giraffe (_G. camelopardalis_) is the sole existing +representative of the genus, now confined to the Ethiopian region. + +In addition to the characters noticed above, the Giraffe is characterised +by its great size and peculiar proportions; the neck and limbs being +of great length, and the back inclining upwards from the loins to the +withers. + +To produce the extremely elongated neck the seven cervical vertebræ are +proportionately long, which gives a somewhat stiff and awkward motion +to the neck. The ears are large, the lips long and thin, the nostrils +closable at the will of the animal, the tongue very long and extensile, +and the tail of considerable length, with a large terminal tuft. An adult +male may have a total height of 16 feet. The coloration consists of large +blotches of darker or lighter chestnut-brown on a paler ground, the +lower limbs and under parts being of a uniform pale colour. The Giraffe +feeds almost exclusively on the foliage of trees, showing a preference +for certain varieties of mimosa, and for the young shoots of the prickly +acacia, for browsing on which its prehensile tongue and large free lips +are specially adapted. It is gregarious in its habits, living in small +herds of about twenty individuals, although Sir S. Baker, who hunted it +in Abyssinia, states that he has seen as many as a hundred together. + +Fossil species of _Giraffa_ occur in Pliocene deposits over Greece, +Persia, India, and China, thus affording one of many striking instances +of the former wide distribution of the generic types now confined to the +Ethiopian region. + +_Allied Extinct Types._—The Pliocene deposits of many parts of the Old +World yield remains of a number of large Ruminants which show such +evident signs of affinity with the Giraffe that it is difficult to draw +up a definition by which they can be separated in characters of family +value from that genus. On the other hand, some of these forms approximate +in the characters of the skull to some of the brachydont members of the +_Bovidæ_, although it is quite clear from the nature of the cranial +appendages that they cannot be included in that family. All these forms +have brachydont molars, with rugose enamel, like those of the Giraffe; +while several of them have limb-bones approximating to those of the +latter—the humerus, when known, having a double bicipital groove. The +nature of the cranial appendages (when present) is not fully understood, +but it appears that in some cases these approximated more to the type of +an antler than to that of a horn; although, from the absence of a “burr,” +they appear never to have been shed. A gradual diminution in the length +of the limbs and neck can be traced from the more Giraffoid to the more +Bovoid forms of this extinct group; and it is manifest that if these +animals be included in the _Giraffidæ_ the definition of that family as +given above must be somewhat modified. Only brief mention can be made of +the more important genera. + +The imperfectly known _Vishnutherium_, of the Pliocene of India and +Burma, seems to make the nearest approach to the Giraffe, but the limbs +and cervical vertebræ were decidedly shorter, although of a similar +slender type. _Helladotherium_, of the Pliocene of Greece and India, is +represented by a species of considerably larger size than the Giraffe, +with no appendages or lachrymal vacuity to the skull, and with shorter +and stouter limbs and neck. + +_Hydaspitherium_, _Bramatherium_, and _Sivatherium_ are Indian genera, +characterised by the presence of large palmated and antler-like cranial +appendages, varying considerably in arrangement. The former genus has a +large lachrymal vacuity which is absent in the two latter. In the first +and second genera all the appendages rise from a common base; but in +_Sivatherium_ there is a pair of simple horn-like projections on the +orbits in addition to the posterior palmated antlers. _Sivatherium_ was +an animal of huge bulk, being the largest known representative of the +Pecora. + +Another apparently allied type is _Samotherium_, of the Pliocene of +the Isle of Samos, which appears also to have some affinity with the +Antelopes. The skull is nearly as large as that of the Giraffe, and is +of the same elongated shape, although depressed between the conical +horn-cores, which rise vertically above the orbits, and without a median +bony prominence on the frontals. The horn-cores form mere processes of +the frontals. The diastema and the mandibular symphysis are shorter than +in the Giraffe, and the latter is less deflected. The teeth, although +larger, are almost indistinguishable from those of the Giraffe, the only +well-marked difference being that the last lower premolar has a double in +place of a single postero-internal column. + + +_Family_ ANTILOCAPRIDÆ. + +Closely allied to the _Bovidæ_, but the horns deciduous and branched. + +_Antilocapra._[209]—The Prong-buck, or Prong-horned Antelope +(_Antilocapra americana_), as the single existing member of this family +is called, is an animal of nearly the same size as the Fallow Deer, but +of a lighter and more graceful build. It is an inhabitant of the prairies +of North America, where it is one of the few representatives of the +Cavicorn Pecora. The bony horn-cores are unbranched, and form vertical, +blade-like projections immediately above the orbit. The horns themselves +are compressed, and nearly one foot in length, having a gentle backward +curvature, the short branch arising somewhat above the middle of its +height, and inclining forwards. When the horn is about to be cast off +it becomes loosened, and a new one is formed upon the bony core beneath +it. The ears are long and pointed, and the tail is short. The neck has a +thick mane of long chestnut-coloured hair, and there is a white patch on +the rump. + + +_Family_ BOVIDÆ. + +Frontal appendages, when present, in the form of non-deciduous horns. +Molars frequently hypsodont. Usually only one orifice to the lachrymal +canal, situated inside the rim of the orbit. Lachrymal bone almost always +articulating with the nasal. Canines absent in both sexes. The lateral +toes may be completely absent, but more often they are represented by +the hoofs alone, supported sometimes by a very rudimentary skeleton, +consisting of mere irregular nodules of bone. Distal ends of the lateral +metapodials never present. Gall-bladder almost always present. The number +of cotyledons in the placenta generally varies from 60 to 100; whereas +in the _Cervidæ_ the number is usually from 5 to 12, _Capreolus_ and +_Hydropotes_ having the fewest. In _Giraffa_ the number is upwards of +180. The nature of the horns and horn-cores has been already explained; +in the majority of genera these appendages are present in both sexes, +although much larger in the male (see p. 310). + +The _Bovidæ_, or hollow-horned Ruminants (Cavicornia), form a most +extensive family, with members widely distributed throughout the Old +World, with the exception of the Australian region; but in America they +are less numerous, and confined to the Arctic and northern temperate +regions, no species being indigenous either to South or Central America. +There is scarcely any natural and well-defined group in the whole +class which presents greater difficulties of subdivision than this; +consequently zoologists are as yet very little agreed as to the extent +and boundaries of the genera into which it should be divided. For the +present the genera provisionally adopted may be arranged under a number +of sections or groups, which some writers regard as subfamilies. The +series may be commenced with the Antelopes, the greater number of which +are now characteristic of the Ethiopian region. + +_Alcelaphine Section._—Includes large African Antelopes, of which the +type genus ranges into Syria; generally characterised by their great +height at the withers as compared with the rump. Skull with large frontal +sinuses, extending into the horn-cores, and the horns lyre-shaped or +recurved, and more or less approximated at the base. No large pits at +apertures of supraorbital foramina in frontals; upper molars hypsodont +and narrow. Horns in both sexes. General colour mostly uniform. + +_Alcelaphus._[210]—If _Damalis_ be included, this genus is represented +by some nine or ten living species. Head more or less long and narrow, +with the muffle moderately broad and naked. Nostrils approximated, edged +with stiff hairs. Horns compressed and ringed at the base, more or less +lyrate, and bent back at the tips. Hoofs small. Tail of moderate length, +and heavy. Two mammæ. + +[Illustration: FIG. 137.—The Harte-beest (_Alcelaphus caama_).] + +In the typical forms, such as the Bubaline Antelope (_A. bubalinus_), the +Harte-beest (_A. caama_, Fig. 137), and the Tora Antelope (_A. tora_, +Fig. 138), the horns, which present the peculiar curvature shown in the +figures, are situated on a crest at the vertex of the skull, and the +facial portion of the cranium is greatly elongated. The Harte-beest, +which is found throughout Central and Southern Africa, stands nearly 5 +feet high at the withers, and is a somewhat ungainly looking animal, with +short hair, which is grayish-brown above and nearly white beneath. In +the Pliocene of the Siwalik Hills in Northern India there occur remains +of an _Alcelaphus_ (_A. palæindicus_) in which the skull had the long +facial portion characteristic of the typical group, while the horns +approximate to those of the Bontebok. The Blessbok (_A. albifrons_) +and Bontebok (_A. pygargus_), belonging to the genus _Damalis_ of many +authors, have the facial portion of the skull shorter, the horns situated +more in advance of the plane of the occiput, and inclining regularly +backwards. Of the Blessbok Mr. C. J. Anderson observes that “it is of a +beautiful violet colour, and is found in company with black Wildebeests +and Springboks in countless thousands on the vast green plains of short +crisp, sour grass occupying a central position in South Africa. Cattle +and horses refuse to pasture on the grassy products of these plains, +which afford sustenance to myriads of this Antelope, whose skin emits a +most delicious and powerful perfume of flowers and sweet-smelling herbs.” +Since the time this was written these Antelopes have been greatly reduced +in number. _A. (Damalis) hunteri_, from East Africa, appears to be allied +to _A. senegalensis_, but in the more elongated facial portion of the +skull approximates to the Harte-beest, and thus confirms the view that +_Damalis_ should not form a distinct genus. + +[Illustration: FIG. 138.—Head of _Alcelaphus tora_. From Sclater, _Proc. +Zool. Soc._ 1873, p. 762.] + +_Connochætes._[211]—Head short and massive, with the muffle very broad +and bristly. Nostrils widely separated, hairy within. Horns on the +vertex of the skull, immediately over the occiput, approximated at base, +cylindrical, bent outwards, and recurving upwards at the tip. Extremities +of premaxillæ much expanded laterally, and firmly ankylosed. Vertebræ: +C 7, D 14, L 6, S 4, C 16. Hoofs very narrow. Tail very long, covered +throughout with long hairs. Four mammæ. Two species, _C. taurina_ and +_C. gnu_ (Fig. 139), both from South Africa. The former, or Brindled +Gnu, is distinguished by the absence of long hair on the face, the black +(instead of white) tail, and the presence of dark vertical streaks on the +shoulders; it is never found to the south of the Orange River. + +The White-tailed Gnu stands about 4 feet 6 inches at the withers. These +animals were formerly found in large herds, and are remarkable not only +on account of their peculiar form, but also for their grotesque actions +when alarmed. Some interesting observations have recently been published +upon the mode of development of the horns of the Gnu,[212] from which +it appears that in very young individuals the horns are straight and +divergent, situated some distance below the vertex of the head, and +separated by a wide hairy interval. These young horns form the straight +tips of those of the adult, the basal downwardly curved portion being +subsequently developed. In the fully adult animal the base of the horns +forms a helmet-like mass on the forehead which completely obliterates the +hairy frontal space of the young. + +[Illustration: FIG. 139.—The White-tailed Gnu (_Connochætes gnu_).] + +_Cephalophine Section._—Small or medium-sized African and Indian +Antelopes, with simple horns present only in the males, a more or less +elongated suborbital gland, a lachrymal depression in the skull, and +square-crowned upper molars (Fig. 140). Lateral hoofs well developed. + +_Cephalophus._[213]—One pair of horns, arising far back on the frontals, +conical, short, angulated at the base, and erect or recurved. Suborbital +gland opening in the form of a slit, or as a row of pores. Auditory bulla +divided by a distinct septum. Muffle large and moist. Tail very short. +Head tufted. Upper molars of larger species with an accessory internal +column. Dorsal vertebræ fourteen in number. Some sixteen species, +confined to southern and tropical Africa. + +The Duikerboks, as the members of this genus are called, are among +the most graceful of the African Antelopes, the smallest species not +being larger than a rabbit. The West African _C. sylvicultor_ and _C. +longiceps_ are the largest species. + +_Tetraceros._[214]—Two pairs of conical horns, of which the anterior are +much the smaller. Suborbital gland elongated, and lachrymal fossa very +large. Upper molars (Fig. 140) without accessory internal column. One +existing Indian species (_T. quadricornis_). + +[Illustration: FIG. 140.—Palatal and outer aspects of the three right +upper premolars and first molar of the Four-horned Antelope (_Tetraceros +quadricornis_). From the _Palæontologia Indica_.] + +The Four-horned Antelope is found throughout the peninsula of India in +jungle. The general colour is brown, lighter beneath and on the inside of +the limbs. Remains of this species are found fossil in the cave-deposits +of Madras, and a small Ruminant from the Pliocene of the Siwalik Hills +has been provisionally referred to this genus. + +_Cervicaprine Section._—Small or large Antelopes now confined to the +Ethiopian region, with horns present only in the males, lachrymal vacuity +generally large, more or less distinct pits at the apertures of the +supraorbital foramina in the frontals, and narrow upper molars in which +there is no accessory internal column. + +_Neotragus._[215]—Distinguished from the next genus by having the crown +of the head tufted, muzzle hairy, premaxillæ long and reaching the +lachrymals, nasals very short, mesethmoid much ossified, third lobe of +last lower molar either absent or very small, and the hinder lobe of the +corresponding upper molar much reduced. + +Three species, Salt’s Antelope (_N. saltianus_), from Abyssinia, and +also _N. kirki_ and _N. damarensis_; the two latter having a small +third lobe to the last molar. Writing of the first-named species, Mr. +W. T. Blanford[216] observes that “the _Beni-Israel_, or _Om-dig-dig_, +one of the smallest Antelopes known, abounds on the shores of the Red +Sea and throughout the tropical and subtropical regions of Abyssinia. +It is occasionally, but rarely, found at higher elevations; I heard of +instances of its being shot both at Serafie and Dildi, but it is not +often seen above about 6000 feet. It inhabits bushes, keeping much to +heavy jungle on the banks of water-courses, and is usually single, or +in pairs, either a male and female or a female and young being found +together; less often the female is accompanied by two young ones, which +remain with her until full grown.” + +_Nanotragus._[217]—Horns small, parallel with frontals, and rising +immediately above postorbital process of frontals, in front of the +fronto-parietal suture. Lachrymal fossa very large, suddenly descending +in front of the orbit, and extending on to the maxilla; lachrymal vacuity +small. Auditory bulla large and smooth, without internal septum. Nasals +of moderate length. Crown of the head smooth; naked part of muffle small; +aperture of suborbital gland small. Lateral hoofs small or absent. Nine +species.[218] + +The typical species is the Royal Antelope (_N. pygmæus_) of Guinea, the +smallest existing representative of the Pecora. This species, together +with _N. moschatus_ and _N. tragulus_ have no lateral hoofs, or tufts on +the knees. In the _Scopophorine_ group, comprising _N. scoparia_, _N. +montanus_, and _N. hastatus_, both these appendages are present; while in +the _Oreotragine_ group (_N. melanotis_ and _N. oreotragus_) the former +are present and the latter absent. + +_Pelea._[219]—Horns rather small, compressed, upright, scarcely +diverging, and placed immediately over the orbits. No suborbital gland, +nor lachrymal fossa; premaxillæ not reaching nasals. Tail short and +bushy. Colour uniform. One species—the Rehbok (_P. capreola_), South +Africa, is nearly of the size of a Fallow Deer, although more resembling +a Chamois in build and habits. The colour is of a uniform light gray. +This animal inhabits bare rocky districts, and thus differs widely from +the Water-buck and its allies. + +_Cobus._[220]—Large Antelopes, with the horns large, elongate, sublyrate, +and ringed at the base, and with rudimentary suborbital glands. Skull +with a deep frontal hollow, no lachrymal depression, large lachrymal +vacuity, and the premaxillæ reaching the very long nasals. Tail long, +with a ridge of hair above, and slightly tufted at the end. Colour +uniform. Six species, African. + +The Antelopes of this genus are water-loving animals, the Water-buck +(_C. ellipsiprymnus_) and the Singsing (_C. defassus_) being well-known +examples. Both these species are much alike, standing as much as 4 feet +6 inches at the withers. The Water-buck of South and Eastern Africa is +characterised by the coarseness of its long hair; while in the Singsing +of West and Central Africa the hair is remarkably fine and soft. +Fossil Antelopes from the Pliocene of India are referred to _Cobus_. +_Helicophora_, from the Lower Pliocene of Attica, is regarded as allied +to _Cobus_, but it has no distinct supraorbital pits. + +_Cervicapra._[221]—An allied South African genus in which the tail is +short and bushy and the premaxillæ do not reach the nasals. Three species. + +The Reitbok (_C. arundineum_) is of a grizzly ochre colour; it stands +nearly 3 feet in height, and has horns about 1 foot in length. The Nagor +(_C. redunca_) is about 6 inches shorter, with horns of half the length, +and fulvous brown above and white below; the West African _C. bohor_ +being rather larger. + +_Antilopine Section._—A large group of moderate-sized or small Antelopes, +most abundant in the deserts bordering the Palæarctic, Oriental, and +Ethiopian regions. Horns generally compressed and lyrate, or recurved, or +cylindrical and spiral, ringed at base, sometimes present in both sexes. +Skull with large pits at apertures of supraorbital foramina of frontals, +and generally a distinct lachrymal fossa. Molars of upper jaw narrow, +without inner accessory column, and resembling those of the Sheep and +Goats. Tail moderate, compressed, hairy above. + +_Antilope._[222]—Horns, present only in the male, long, cylindrical, +subspiral, and diverging. Suborbital gland large, with a somewhat linear +opening; lachrymal depression of skull very large, and a small lachrymal +fissure. Glands in the feet; lateral hoofs present. One species, India. + +The well-known Black-buck (_A. cervicapra_) is found on open plains +all over India, except in lower Bengal and Malabar. Old males are deep +blackish-brown in colour on the back and sides and the outer surfaces of +the limbs, the under parts and inner surfaces of the limbs white, and +the back of the head, nape, and neck yellowish. Young males and females +are fawn-coloured above. Very large herds are seen in the plains about +Delhi and Mattra, which are said in some instances to reach to thousands. +Horn-cores are found in the Pleistocene deposits of the valley of the +Jumna which cannot be distinguished from those of the existing species. + +_Æpyceros._[223]—Horns compressed, lyrate, and wide-spreading; present +only in male. No suborbital gland, or lachrymal depression in the skull. +No lateral hoofs. Two species; one from South and the other from West +Africa. + +The Palla (_Æ. melampus_) is a large Antelope standing over 3 feet +high at the withers, and readily distinguished by its dark red colour, +gradually shading to white below. It is usually found on or near hills in +herds of from twenty to thirty. _Æ. petersi_ is from the Congo. + +_Saiga._[224]—Nose very large, convex, and inflated. Supraorbital gland +present. Lachrymal fossa of skull small, and fissure absent; narial +aperture very large; nasals extremely short; supraorbital pits rather +small. Horns yellow, lyrate, of moderate length; present only in male. +Vertebræ: C 7, D 13, L 6, S 4, C 10. One species, Eastern Europe and +Western Asia. + +The Saiga (_S. tatarica_) is a clumsily built and somewhat sheep-like +Antelope inhabiting the steppes; it occurs fossil in the Pleistocene of +France and England. + +_Pantholops._[225]—Allied in the characters of the head and skull to +_Saiga_, but the nose less convex, the nostrils of the male more swollen, +and the horns of that sex black, very long, compressed, and lyrate; those +of female very short. One species, Central Asia. + +The Chiru (_P. hodgsoni_) inhabits the highlands of Western Tibet and +Turkestan. In the former area it generally goes in small herds of from +three to six, and in the summer may be found grazing in early morning on +the level spaces frequently found in the river valleys at elevations of +about 15,000 feet. It is excessively shy and difficult to approach. The +large size of the narial aperture in the skull of Chiru is suggestive of +a connection with respiration at a high altitude, but this appears to be +negatived by the occurrence of the same feature in the Saiga. + +_Gazella._[226]—Delicately built and sandy-coloured Antelopes, with +lyrate or recurved horns, which may be absent in the female, and are +always smaller and simpler in that sex than in the male. Skull with +moderate lachrymal fossa, and a distinct lachrymal fissure. Vertebræ: C +7, D 13, L 6, S 4, C 14. Suborbital gland frequently small, and covered +with hair. Face with a white streak running from the outer side of the +base of each horn nearly down to the upper end of each nostril, cutting +off a dark triangular central patch, and bordered externally by a +diffused dark line (see Fig. 121, p. 310). The Gazelles, of which there +are some twenty-four existing species, are typically Palæarctic desert +forms, the Springbok (_G. euchore_) being an outlying South African +species. _G. picticaudata_ and _G. gutturosa_ are respectively found in +Western Tibet and Mongolia, the former at great elevations. The majority +of the Gazelles do not exceed 30 inches in height, although _G. mohr_ is +36. Sir Victor Brooke classifies[227] the Gazelles as follows:— + + A. No stripe on back; three lower premolars. + + _a._ White of rump not encroaching on the fawn of the haunches. + + I. Female with horns. + + 1. Horns lyrate or sublyrate—_G. dorcas_, _G. isabella_, + _G. rufifrons_, _G. lævipes_, _G. tilonura_, _G. naso_. + + 2. Horns non-lyrate—_G. cuvieri_, _G. leptoceros_, _G. + spekei_, _G. arabica_, _G. bennetti_, _G. fuscifrons_, + _G. muscatensis_. + + II. Female without horns. + + _G. subgutturosa_, _G. gutturosa_, _G. picticaudata_. + + _b._ White of rump projecting forwards in an angle into the + fawn colour of the haunches. Horns in both sexes. + + _G. dama_, _G. mohr_, _G. soemmerringi_, _G. granti_ + (Fig. 121), _G. thomsoni_. + + B. A white stripe down the back, two lower premolars. Horns in + both sexes.—_G. euchore._ + +The East African _G. walleri_ is an aberrant species, in which the +females are hornless, which has been made the type of the genus +_Lithocranius_. It is characterised by the extreme density of the horns +and skull, the slenderness of the mandible, and the small size of the +cheek-teeth, the upper molars being relatively broader and lower than +usual. The cranium is remarkable for the shortness of its facial portion, +the large size and production backwards of the supraoccipital, and for +the circumstance that the long basicranial axis is nearly parallel with +the plane of the palate. + +Fossil species of _Gazella_ are found in the Pliocene and Pleistocene +deposits of Europe and India. _G. deperdita_ (_brevicornis_), of the +Lower Pliocene of France and Greece, appears to be a generalised species +in which the lower molars frequently have accessory columns, traces of +which are found in some of the existing forms. + +_Hippotragine Section._—Includes very large African Antelopes, with long +horns, present in both sexes, which are placed over or behind the orbit, +and are either recurved, straight, or subspiral. Skull with no distinct +pits at apertures of supraorbital foramina in frontals, no lachrymal +fossa, and only a small lachrymal fissure. No suborbital gland. Tail +long, cylindrical, and tufted at the end. Upper molars extremely +hypsodont, very broad, and with large accessory columns, thus closely +resembling those of the Oxen. Some authorities divide this section into +two. In the Pliocene it occurs in India and Europe. + +_Hippotragus._[228]—Horns stout, rising vertically from a crest over +the orbit at an obtuse angle to the plane of the nasals, then recurved; +lachrymal fissure in some instances almost obliterated. Neck with an +erect recurved mane. Tail very distinctly tufted. Four species, tropical +Africa and south to the Cape. + +The Sable Antelope (_H. niger_) is one of the best-known examples of this +genus, occurring in South and East Africa. It stands upwards of 4½ feet +in height at the withers, and, except for some white streaks on the face +and the whole of the under surface of the body, is of a black colour. +The Blaubok (_H. leucophæus_) is distinguished by the glaucous hue of +the hair. The other species are the Equine Antelope (_H. equinus_) and +Baker’s Antelope (_H. bakeri_) from the Sudan, both closely allied, but +the latter distinguished by its pale fulvous colour, pencilled ears, and +black stripes on the shoulder. + +Skulls of fossil Antelopes from the Pliocene of India have been referred +to _Hippotragus_ (_H. sivalensis_), and Sir V. Brooke suggests that the +European Pliocene _Antilope recticornis_ is not generically separable. + +_Oryx._[229]—Horns long, slender, nearly straight or somewhat recurved, +rising behind the orbit, and inclining backwards in the plane of the +nasals; lachrymal fossa distinct. Nape maned; tail long, and more haired +than in _Hippotragus_. Four species, ranging over all the African deserts +to Arabia and Syria. + +The Gemsbok (_O. gazella_, Fig. 141), is a South African species +characterised by its straight horns, the presence of a tuft of hair on +the throat, as well as by the large patches and stripes of black on the +head, back, limbs, and flanks. It stands nearly 4 feet in height at the +shoulder, and the horns are 2 feet 9 inches in length. The colour of the +upper part of the body is a rusty gray, and of the under part white, +while these are separated from each other by a well-defined black band +on either side. These bands unite on the breast, and are continued as a +single black band until reaching the lower jaw, where they again divide +and form two transverse bands on the head, terminating at the base of +the horns. The head otherwise is white, as also are the limbs, with the +exception of the thighs, which are black. The Gemsbok generally goes +in pairs, or in small herds of three or four. The Beisa (_O. beisa_) +of Abyssinia is distinguished by the absence of the tuft of hair on +the throat. Writing of this species in his _Geology and Zoology of +Abyssinia_, Mr. W. T. Blanford observes that “the appearance of a herd of +Oryx is very imposing. They are some of the most elegant and symmetrical +of animals, the motions being those of a wild Horse rather than of an +Antelope. Their favourite pace appears to be either a steady quick walk +or a trot; they rarely break into a gallop unless greatly alarmed. When +frightened they dash off, sometimes snorting and putting their heads down +as if charging, raising their long tails, and looking very formidable. +They are wary animals, though far less so than some other Antelopes. It +is said that they frequently attack when wounded, and their long straight +horns are most deadly weapons.” The Arabian Beatrix Antelope (_O. +beatrix_) is a much smaller animal, with the black markings confined to +the head, fore limbs, and flanks. Finally, the Leucoryx (_O. leucoryx_) +of North Africa, while agreeing in size with the Beatrix, differs by its +curved horns and uniform coloration. + +[Illustration: FIG. 141.—The Gemsbok (_Oryx gazella_).] + +The extinct _Palæoryx_, of the Lower Pliocene of Europe and the Isle of +Samos, appears to have been an ancestral form of _Oryx_, said to show +some signs of affinity with _Hippotragus._ + +_Addax._[230]—Horns with the same inclination as in _Oryx_, but with a +slight spiral twist. No mane on nape, but a slight one on the throat. +Hoofs rounded. One species (_A. nasomaculatus_), from North Africa and +Arabia, the colour of which is nearly white. + +_Tragelaphine Section._—Includes large, so-called Bovine, Antelopes now +mainly characteristic of the Ethiopian region, but with one Oriental +genus. Horns usually present in the male only (if developed in the female +smaller), with a more or less distinct ridge in front, and usually +twisted spirally, the front ridge twisting outwards from the base of the +horn. Skull without lachrymal fossa, but with a large or small lachrymal +fissure; usually large pits at the apertures of the supraorbital foramina +on the frontals; premaxillæ reaching nasals. Muffle large and moist; +nostrils approximated. Molars hypsodont or brachydont. Vertical white +stripes frequently present on the body. + +_a._ _Hind limbs much shorter than the fore. Horns behind the orbit, +short, conical, faintly angulated. Nose bovine. Body without vertical +stripes. Molars_ (Fig. 123, p. 311) _hypsodont, with a large accessory +column in those of the upper jaw. One Oriental genus._ + +_Boselaphus._[231]—The one genus of this subsection is represented only +by the well-known Nilghai (_B. tragocamelus_) of India. The male stands +over 4 feet in height at the shoulder, with horns about 8 inches in +length; the hornless female being about one third smaller. Both sexes +have a short erect mane, and the male has also a tuft of hair upon the +throat. When adult the sexes are very different in colour, the male being +of a dark iron gray or slate colour, approaching black on the head and +legs, while the female and young are of a bright light brown or fawn +colour. In both male and female at all ages the lips, chin, and under +parts, as well as two transverse stripes on the inner sides of the ears +and rings on the fetlocks, are white, and the mane and tip of the tail +black. The Nilghai is one of the few Antelopes occurring in India, where +it is found from near the foot of the Himalaya to the south of Mysore, +though rare to the north of the Ganges and also in the extreme south. It +is most abundant in Central India, and does not occur in Assam or the +countries to the east of the Bay of Bengal. It frequents forests and low +jungles, though often found in tolerably open plains, associating in +small herds. One, or very often two, young produced at a birth. Fossil +remains of species of this genus occur in the Pleistocene and Pliocene +deposits of India. + +_b._ _Fore and hind limbs equal. Horns long, and spirally twisted. Nose +cervine, and aperture of suborbital gland very small. Body generally +striped. Molars brachydont, those of the upper jaw in existing forms with +a smaller inner accessory column. Three existing Ethiopian genera._ + +_Tragelaphus._[232]—Female hornless. Horns of males (Fig. 142) over +orbit, with one or two spiral turns, obscurely ridged, the posterior +ridge being more developed than the anterior. Skull with small +supraorbital pits, very small lachrymal fissure, and no deep intercornual +depression in the frontals. Neck maned or smooth. Hoofs short or long. +Coloration usually brilliant, differing markedly in the two sexes, and +the white bands on the body, when present, numerous and distinct. Seven +species. + +[Illustration: FIG. 142.—Head of _Tragelaphus gratus_. From Sclater, +_Proc. Zool. Soc._ 1883, p. 36.] + +The Harnessed Antelopes are among the handsomest of the whole group. The +small Guib (_T. scriptus_) is not larger than a Goat, but _T. angasi_ is +3 feet 4 inches in height at the shoulder. In _T. scriptus_, _T. angasi_, +and _T. euryceros_, the two sexes differ in colour, the body is marked by +white stripes descending from a white dorsal streak, and the hoofs are +short; the third species differing from the others by the absence of a +mane on the neck, back, and belly. _T. gratus_ agrees with this group in +coloration (the mane being absent), but differs in the extreme elongation +of its hoofs. The Nakong, _T. spekei_, while having the long hoofs of +_T. gratus_, has a perfectly plain body coloration, with a mane on the +neck. The two species with elongated hoofs inhabit swampy districts, for +which this peculiar structure is admirably adapted; and the Nakong, when +frightened, will rush into the water and leave only its nostrils and the +tips of the horns above the surface. The small Bushbuck (_T. sylvaticus_) +of South Africa has no stripes, and short hoofs. + +[Illustration: FIG. 143. The Kudu (_Strepsiceros kudu_). From Sclater, +_List of Animals in Zoological Society’s Gardens_, 1883, p. 136.] + +_Strepsiceros._[233]—Females hornless. Horns (Fig. 143) more twisted +than in _Tragelaphus_, forming an open spiral, with the anterior ridge +very strongly developed, and rising at an obtuse angle to the plane of +the nasals. Skull with large supraorbital pits, large lachrymal fissure, +and deep intercornual depression. Hoofs short. Body with white vertical +stripes descending from a longitudinal dorsal streak. Two existing +species. + +The Kudu (_S. kudu_, Fig. 143) extends from South Africa to Abyssinia, +and is only inferior in size to the Eland. The horns are about 4 feet +in length, and form a very open spiral, and there is a fringe of long +hair down the front of the neck. The Lesser Kudu (_S. imberbis_), of +Somali-land is a much smaller form, without the fringe of hair on the +neck, and with a much smaller axis formed by the spiral of the horns. + +An imperfect skull from the Pliocene of Northern India has been referred +to _Strepsiceros_. + +_Oreas._[234]—Females horned. Horns twisted on their own axis, with very +strong ridges, inclining upwards and outwards in the plane of the nasals. +General characters of skull as in preceding genus. Stripes on body, if +present, very faintly marked. One existing species. + +The Eland (_O. canna_) is the largest of all the Antelopes, the males +standing nearly 6 feet at the withers. One variety from South Africa +is of a uniform pale fawn colour, while the Central African form is of +a bright tan colour, marked by a number of thin pale vertical stripes +descending from a dark dorsal ridge—these markings fading more or less in +the adults. The males have a large dewlap, a tuft of brown hair on the +forehead, and a small mane on the neck. The straight black horns of the +male are usually about 18 inches long. Elands were formerly extremely +abundant in Southern and Eastern Africa, but their destruction has been +so relentless that they have totally disappeared from extensive areas, +and are daily becoming scarcer. + +Portions of upper jaws from the Pliocene deposits of India appear to +indicate the former existence in that area of large Antelopes closely +allied to the Eland, but distinguished from the living species by the +greater size of the inner accessory column in the upper molars. + +_Allied Extinct Types._—Large Antelopes with spirally twisted horns +appear to have been common over Southern Europe in Pliocene times, but +their exact affinity is in many cases difficult to determine. Of these, +_Palæoreas_, which occurs in the Lower Pliocene of Europe and Algeria, +appears to present affinities both to _Oreas_ and _Strepsiceros_, and may +have been the ancestral type from which these two genera are derived; the +upper molars have well-developed accessory columns. + +The so-called _Antilope torticornis_, of the French Pliocene, resembles +_Tragelaphus_ in the greater development of the posterior as compared +with the anterior ridge of the horn-cores, and has accordingly been +referred to that genus. _Protragelaphus_, of the Lower Pliocene of +Attica, differs from all the other types in the absence of the anterior +ridge on the horn-cores and of the supraorbital pits, while it has a +distinct lachrymal fossa. + +In this place it will be convenient to notice certain fossil forms which +do not accord with any of the existing sections of the family, and for +the reception of which the _Palæotragine_ section has been formed. In +these types the horn-cores are laterally compressed like those of the +modern Goats, but the upper molars resemble those of the brachydont +Antelopes. The earliest of these genera, and the first representative +of the Antelopes yet known, is _Protragoceros_, of the Middle Miocene +of France, first described as _Antilope clavata_; _Palæotragoceros_ and +_Tragoceros_, of the Lower Pliocene, are distinguished by their larger +horns and wider molars. + +A remarkable large Antelope from the Lower Pliocene of the Isle of Samos, +in the Turkish Archipelago, proposed to be described as _Criotherium_, +appears to be unlike any other form. The horns, which are placed on the +extreme vertex of the skull, are very short, tightly twisted, and project +in front of the forehead. The upper molars have short and broad crowns, +with no accessory column on the inner side. + +_Rupicaprine Section._—The Caprine Antelopes, as the typical members of +this section may be termed, appear to connect the true Antelopes with the +Goats. They are mostly small or medium-sized forms, inhabiting portions +of the Palæarctic and Oriental regions, with one outlying North American +genus. The typical forms present the following features. Horns present, +and of nearly equal size in both sexes, rising behind the orbits, short, +ringed at the base, conical or somewhat compressed, and recurved. +Suborbital gland generally present, in some cases small. Build clumsy; +hoofs large; tail short, tapering, hairy above. Skull with lachrymal +fossa, but no fissure. Molars as in the Caprine section. + +_Rupicapra._[235]—Horns short and cylindrical, rising perpendicularly +from the forehead for some distance, then bending sharply backwards and +downwards, forming hooks with pointed tips. Premaxillæ not reaching the +nasals. One species, Palæarctic. + +The Gemse, or Alpine Chamois (_R. tragus_), inhabits the high mountains +of Europe from the Pyrenees to the Caucasus. It stands about 2 feet in +height at the withers. The body is covered in winter with long hair of a +chestnut-brown colour, that of the head being paler, with a dark brown +streak on each side. At other seasons the colour is somewhat lighter, in +spring approaching to gray. Underneath the external covering the body is +further protected from cold by a coat of short thick wool of a grayish +colour. The tail is black; the ears are pointed and erect; the hoofs have +the outer edges higher than the soles, and are thus admirably adapted for +laying hold of the slightest projection or roughness on the face of the +rocky precipices it frequents. The Chamois is gregarious, living in herds +of fifteen or twenty, and feeding generally in the morning or evening. +The old males, however, live alone, except in the rutting season, which +occurs in October, when they join the herds, driving off the young males, +and engaging in contests with each other that often end fatally. The +period of gestation is twenty weeks, when the female, beneath the shelter +of a projecting rock, produces one and sometimes two young. In summer the +Chamois ascends to the limits of perpetual snow, being only outstripped +in the loftiness of its haunts by the Ibex; and during that season it +shows its intolerance of heat by choosing such browsing grounds as have a +northern exposure. + +[Illustration: FIG. 144.—_Nemorhædus crispus._ From Sclater, _List of +Animals in Zoological Society’s Gardens_, 1883, p. 151.] + +_Nemorhædus._[236]—Horns rounded, gradually recurving, without distinct +hook at the end. Suborbital gland small or wanting; ears large; skull +with a large lachrymal depression, and the premaxillæ not quite reaching +the nasals. Some nine species, ranging from the Eastern Himalayas to +North China and Japan, and southwards to Formosa, the Malay Peninsula, +and Sumatra. The smallest species is the Himalayan Goral (_N. goral_). Of +the larger forms we may mention the Himalayan Serow (_N. bubalinus_) the +Cambing-Utan (_N. sumatrensis_) of Sumatra, and the Japanese _N. crispus_ +(Fig. 144). Of the Serow, Colonel Kinloch remarks that “it is a large and +powerful beast. The body is covered with very coarse hair, which assumes +the form of a bristly mane on the head and shoulders, and gives the +beast a ferocious appearance, which does not belie its disposition. The +colour is a dull black on the back, bright red on the sides, and white +underneath, the legs also being dirty white. The ears are very large, the +muzzle is coarse. The Serow has an awkward gait, but in spite of this can +go over the worst ground; and it has perhaps no superior in going down +steep hills. It is a solitary animal, and nowhere numerous.” + +_Haploceros._[237]—The Rocky-Mountain Goat (_Haploceros montanus_), +inhabiting the northern parts of California, appears to be very closely +allied to _Nemorhædus_. The horns are somewhat compressed at the base; +there is no suborbital gland; and the ears are small. The hair, which is +whitish in colour, is very long, and especially abundant in the region of +the throat, shoulders, flanks, and tail. The animal is about the size of +a large Sheep. + +_Budorcas._[238]—The Takin (_B. taxicolor_) of the Mishmi Hills in Assam, +and an allied species from Eastern Tibet, are larger forms apparently +related to _Nemorhædus_, but with a much greater development of the +horns. The horns of what is considered to be the male[239] arise from +the vertex of the skull, and are nearly in contact in the middle line; +they first bend outwards and downwards, and then suddenly upwards +and backwards. Those regarded by Mr. Hume as referable to the female +are directed at first outwards, and then gradually curve upwards and +backwards, without any downward flexure or angulation. The horns of +the male may be 2 feet in length, with a basal diameter of 13 inches. +The muzzle is hairy, with a small naked muffle. There appear to be +considerable seasonal and sexual variations in colour; the body being in +some cases of a yellow dun, while in others it is a dusky, reddish-brown, +with much black intermingled. The heads of large males are blackish. + +Scarcely anything is known of the habits of the Takin, which never +appears to have been seen alive by Europeans. + +_Caprine Section._—Both sexes with horns, but those of the female small. +Horns usually compressed, triangular, with transverse ridges, and either +curving backwards or spiral. Muzzle hairy, without naked muffle. +Suborbital gland small or absent; lachrymal fossa of skull present or +absent. Tail short and flattened. Foot-glands frequently present. Molars +very hypsodont; those of the upper jaw being narrow, without an accessory +internal column. Mainly Palæarctic, but with some outlying forms. + +This section includes the Goats and Sheep, which are so closely connected +that it is difficult to give well-marked generic characters that will +hold good for all the species. They seem to be one of the latest +developments of the _Bovidæ_, since they are unknown before the Pliocene +period; and are essentially mountain forms. + +[Illustration: FIG. 145.—The Alpine Ibex (_Capra ibex_).] + +_Capra._[240]—Horns flattened from side to side, and either curving +backwards (Fig. 145) or spirally twisted. No suborbital gland, and no +lachrymal fossa in the skull. Foot-glands, if present, only in the fore +feet. Chin more or less bearded. Males with a strong odour. Vertebræ: +C 7, D 13, L 6, S 4, C 9-13. Some dozen species, ranging over all the +higher mountains of Southern Europe, from Spain to the Caucasus; also +found in Abyssinia, Persia, Sind, and Baluchistan, thence through the +higher Himalaya, and so on to Tibet and Northern China. One outlying +species occurs in the Nilgherries of Southern India. + +The European Ibex or Steinbok (Fig. 145), which may be taken as a typical +Goat, stands about 2½ feet in height at the shoulder. In summer the hair +is short and smooth, and of an ashy-gray colour, but a long coat is +developed in winter. The horns of the male rise in a bold backward sweep +from the forehead, and are characterised by the strong transverse ridges +on the broad and flat anterior surface. They are said to be not more +than some 2 feet in length, but these dimensions are greatly exceeded +by the horns of the Himalayan Ibex. The Alpine Ibex lives at a greater +height than the Chamois, spending the day just at the limit of perpetual +snow, and descending at night to graze at lower levels. Both this and the +Himalayan species generally live in small herds of from five to fifteen +or more; they are wary animals, although not so much so as many of the +wild Sheep. The following list, mainly taken from two papers by Mr. +Sclater,[241] gives the distribution of the various species of Goats, +with some remarks on their peculiarities:— + +(1) _C. ibex_, confined to the Alps of Switzerland, Savoy, and the +Tyrol, and now nearly extinct, except where artificially preserved. +(2) _C. sibirica_, closely allied to the preceding, but with larger +horns, occurs in the Altai Mountains, and throughout the Himalaya from +Kashmir to Nipal, and northward towards Turkestan. (3) _C. sinaitica_, +of the mountains of Upper Egypt, the Sinaitic Peninsula, and Palestine, +is allied to the two preceding species, but has the horns somewhat +more compressed, with a difference in the ridges on the front. (4) _C. +caucasica_, a very distinct species, confined to the Caucasus, where +it inhabits the western part of the Great Caucasus; with thick horns +curving backwards and outwards in one plane, with the exception of their +tips, which incline inwards.[242] (5) _C. pallasi_ is an allied species +from the Eastern Caucasus, distinguished, among other features, by the +curvature of the horns, which lie flatter and twist more outward from +the forehead, with a greater terminal inward bend. (6) _C. pyrenaica_, +of the Pyrenees, and the higher ranges of Central Spain, Andalusia, and +Portugal, is another nearly related species. (7) _C. ægagrus_, formerly +abundant over the Grecian Archipelago, but now restricted in Europe to +Crete and some of the Cyclades, is found throughout the mountains of +Asia Minor and Persia, and thence to Baluchistan and Sind. The horns +are thinner and sharper in front than in the Ibexes, and this species +is generally regarded as the ancestral stock of the various breeds of +domestic Goats. (8) _C. dorcas_, a Goat from the island of Jura, near +Eubœa, has been described under this name, and is apparently nearly +allied to _C. ægagrus_. (9) _C. walie_, an apparently well-characterised +species from the highest ranges of Abyssinia. (10) _C. falconeri_; the +Markhoor differs from all the preceding species by the spiral twisting of +its horns, which attain enormous dimensions. It occurs in the Pir-Panjal +range south of Kashmir, and thence into Afghanistan and the Suleiman +range, and northwards to Astor, Gilgit, and Scardo (Baltistan). The +specimens from the Suleiman range have the spiral of the horns very +close, somewhat as in the Eland; while in those from Astor, Gilgit, and +Scardo it is very open, as in the Kudu. The Pir-Panjal race occupies a +somewhat intermediate position in this respect. (11) _C. jemlaica_, the +Thar, inhabits suitable regions along the whole range of the Himalaya +from Kashmir to Bhutan. Together with the next species, it differs from +the more typical Goats in its short, thick, and much compressed horns, +the anterior border of which is keeled, and the moist naked muffle. There +are no glands in the fore feet. It was generically separated by Gray as +_Hemitragus_. (12) _C. hylocrius_, the so-called Ibex of the Nilgherries, +Anamallays, and other adjoining ranges of Southern India, is an outlying +species, apparently allied to the preceding, but with somewhat different +horns, in which the external angle in front is much rounded off. + +Of fossil Goats we have but little knowledge. Remains of _C. pyrenaica_ +are found in cave-deposits at Gibraltar; and it is not improbable that +the genus is represented in the Upper Pliocene of France. Several species +occur in the Pliocene of India, _C. sivalensis_ being apparently closely +allied to _C. jemlaica_, while another has horns resembling those of _C. +falconeri_, and it is possible that a third may be more nearly related to +the Ibexes. + +_Ovis._[243]—Horns curving backwards and downwards in a bold sweep, +with the tips everted, generally with more or less prominent transverse +ridges, and brownish in colour. Suborbital gland and lachrymal fossa +usually present, but generally small. Foot-glands in all the feet. Chin +not bearded;[244] males without a strong odour. Vertebræ: C 7, D 13, L +6, S 4, C 10-14. Some twelve species, mainly Palæarctic, but extending +into the adjacent portions of the Oriental region, and with one outlying +species in North America. + +The more typical Sheep are closely connected with the Goats by the +Himalayan Bharal (_O. nahura_) and the Aoudad (_O. tragelaphus_) of +Northern Africa, both these species having no suborbital gland and no +lachrymal fossa, while their comparatively smooth and olive-coloured +horns show a decided approximation to those of the Goats. Both present, +however, the ovine character of glands in all the feet. In the typical +Sheep the basioccipital of the skull is wider in front than behind, +with the anterior pair of tubercles widely separated and much larger +than the posterior pair. The Bharal, however, resembles the Goats in +having an oblong basioccipital, with the posterior tubercles larger and +more prominent than the anterior ones, both being situated in the same +antero-posterior line. These transitions towards the caprine type are, +however, not sufficient to support the view that the Bharal should form +the type of a distinct genus (_Pseudois_), more especially since some of +the typical Sheep, like _O. canadensis_, have the lachrymal fossa of the +skull very much reduced in size. + +The distinction of the various permanent modifications under which wild +Sheep occur is a matter of considerable difficulty. Trivial characters, +such as size, slight variations in colour, and especially the form and +curvature of the horns, are relied upon by different zoologists who have +given attention to the subject in the discrimination of species, but no +complete accord has yet been established. The most generally recognised +forms are enumerated below. + +The geographical distribution of wild Sheep is interesting. The immense +mountain ranges of Central Asia, the Pamir and Thian-Shan of Turkestan, +may be looked upon as the centre of their habitat. Here, at an elevation +of 16,000 feet above the sea-level, is the home of the magnificent +_Ovis poli_, named after the celebrated Venetian traveller Marco Polo, +who met with it in his adventurous travels through this region in the +thirteenth century. It is remarkable for the great size of the horns of +the old rams and the wide open sweep of their curve, so that the points +stand boldly out on each side, far away from the animal’s head, instead +of curling round nearly in the same plane, as in most of the other +species. A Sheep from the same region, in which the horns retain their +more normal development, has received the name of _O. karelini_, but, +according to Mr. W. T. Blanford,[245] is not distinct specifically from +_O. poli_. Eastward and northward is found the Argali (_O. argali_), +with a wide and not very well determined range; it formerly occurred in +the Altai, but is now found in Northern Mongolia. Still farther north, +in the Stanovoi Mountains and Kamschatka, is _O. nivicola_, and away on +the other side of Behring’s Strait, in the Rocky Mountains and adjacent +highlands of western North America, is the “Bighorn” or Mountain Sheep +(_O. canadensis_), the only member of the genus found in that continent, +and indeed—except the Bison, Musk-Ox, Mountain Goat (_Haploceros_), and +the Prong-buck (_Antilocapra_)—the only hollow-horned Ruminant, being +like the rest obviously a straggler from the cradle of its race. The two +last-named species are nearly allied, and are characterised by the slight +development of the ridges on their horns and the very shallow lachrymal +fossa. Turning southward from the point from which we started, and +still a little to the east, in Nipal and Western Tibet, is the Himalayan +Argali (_O. hodgsoni_), having massive and strongly curved horns, with +bold ridges, like those of the true Argali. Indeed, were it not for their +isolated areas there would appear to be no grounds for distinguishing +these two closely allied forms, and it is not improbable that they +are really identical. _O. brookei_, appears to have been founded on a +hybrid between _O. hodgsoni_ and _O. vignei_. In the same districts, +and also in Southern Ladak, there occurs the Bharal (_O. nahura_), with +smaller, smoother, and more spreading horns. Passing in a south-westerly +direction we find a series of smaller forms, _O. vignei_ of Ladak, _O. +cycloceros_ of Northern India, Persia, and Baluchistan. _O. gmelini_ of +Asia Minor and Persia, _O. ophion_, confined to the elevated pine-clad +Troodos Mountains of the island of Cyprus, and said at the time of the +British occupation in 1878 to have been reduced to a flock of about +twenty-five individuals, and _O. musimon_, the Moufflon of Corsica and +Sardinia (see Fig. 146), believed to have been formerly also a native of +Spain. In the three latter species the females are hornless. Lastly, we +have the somewhat aberrant, Goat-like Aoudad (_O. tragelaphus_), of the +great mountain ranges of North Africa, in which, as already mentioned, +the skull and horns resemble those of the Bharal, although the tail is +longer, and there is a thick fringe of long hair on the throat, chest, +and fore legs. + +[Illustration: FIG. 146.—The Moufflon (_Ovis musimon_). From a living +animal in the London Zoological Gardens.] + +We thus find that Sheep are essentially inhabitants of high mountainous +parts of the world, for dwelling among which their wonderful powers of +climbing and leaping give them special advantages. No species frequent +by choice either level deserts, open plains, dense forests, or swamps. +By far the greater number of species are inhabitants of the continent of +Asia, one extending into North America, one into Southern Europe, and one +into North Africa. No wild Sheep exist in any other part of the world, +unless the so-called Musk-Ox of the Arctic regions, the nearest existing +ally to the true Sheep, may be considered as one. Geologically speaking, +Sheep appear to be very modern animals, or perhaps it would be safer to +say that no remains that can be with certainty referred to the genus +have been met with in the hitherto explored true Tertiary beds, which +have yielded such abundant modifications of Antelopes and Deer. They are +generally considered not to be indigenous in the British Isles, but to +have been introduced by man from the East in prehistoric times. A fossil +Sheep (_Ovis savigni_), apparently allied to the Argali, has, however, +been described from the so-called Forest-bed of the Norfolk coast. + +The Sheep was a domestic animal in Asia and Europe before the dawn of +history, though quite unknown as such in the New World until after the +Spanish conquest. It has now been introduced by man into almost all +parts of the world where settled agricultural operations are carried on, +but flourishes especially in the temperate regions of both hemispheres. +Whether our well-known and useful animal is derived from any one of the +existing wild species, or from the crossing of several, or from some +now extinct species, is quite a matter of conjecture. The variations of +external characters seen in the different domestic breeds are very great. +They are chiefly manifested in the form and number of the horns, which +may be increased from the normal two to four or even eight, or may be +altogether absent in the female alone, or in both sexes; in the form and +length of the ears, which often hang pendent by the side of the head; +in the peculiar elevation or arching of the nasal bones in some Eastern +races; in the length of the tail, and the development of great masses of +fat at each side of its root, or in the tail itself; and in the colour +and quality of the fleece. + +_Ovibos._[246]—This genus is generally considered to be a connecting link +between the Caprine and Bovine sections, but should rather be regarded as +an aberrant type of the former. Horns of adult male rounded, smooth, and +closely approximated at their bases, where they are depressed and rugose; +curving downwards, and then upwards and forwards. Muzzle caprine; no +suborbital gland, no lachrymal fossa or fissure in skull; orbits tubular; +a large narial aperture and very short nasals; premaxillæ not reaching +nasals. Tail short, and molar teeth caprine. One existing and two fossil +species, Palæarctic and Nearctic. + +[Illustration: FIG. 147.—The Musk-Ox (_Ovibos moschatus_).] + +The animal commonly known as the Musk-Ox (_Ovibos moschatus_), though +approaching in size the smaller varieties of Oxen, is in structure and +habits closely allied to the Sheep, its affinities being well expressed +by the generic name _Ovibos_ bestowed upon it by De Blainville. The +specific name, as also the common English appellatives “Musk-Ox,” +“Musk-Buffalo,” or “Musk-Sheep,” applied to it by various authors, refer +to the musky odour which the animal exhales. This does not appear to be +due to the secretion of a special gland, as in the case of the Musk-Deer; +but it must be observed that, except as regards the osteology, very +little is known of the anatomy of this species. It about equals in size +the small Welsh and Scotch cattle. The head is large and broad. The horns +in the old males have extremely broad bases, meeting in the median line, +and covering the brow and whole crown of the head. They are directed +at first downwards by the side of the face and then turn upwards and +forwards, ending in the same plane as the eye. Their basal halves are of +a dull white colour, oval in section and coarsely fibrous; their middle +part smooth, shining, and round; their tips black. In the females and +young males the horns are smaller, and their bases are separated from +each other by a space in the middle of the forehead. The ears are small, +erect, and pointed, and nearly concealed in the hair. The space between +the nostrils and the upper lip is covered with short close hair, as in +Sheep and Goats, without any trace of the bare muffle of the Oxen. +The greater part of the animal is covered with long brown hair, thick, +matted, and curly on the shoulders, so as to give the appearance of a +hump, but elsewhere straight and hanging down,—that of the sides, back, +and haunches reaching as far as the middle of the legs and entirely +concealing the very short tail. There is also a thick woolly under-fur, +shed in the summer. The hair on the lower jaw, throat, and chest is long +and straight, and hangs down like a beard or dewlap, though there is no +loose fold of skin in this situation as in Oxen. The limbs are stout +and short, terminating in unsymmetrical hoofs, the external one being +rounded, the internal pointed, and the sole partially covered with hair. + +The Musk-Ox is at the present day confined to the most northern parts of +North America, where it ranges over the rocky barren grounds between the +60th parallel and the shores of the Arctic Sea. Its southern range is +gradually contracting, and it appears that it is no longer met with west +of the Mackenzie River, though formerly abundant as far as Eschscholtz +Bay. Northwards and eastwards it extends through the Parry Islands and +Grinnell Land to North Greenland, reaching on the west coast as far south +as Melville Bay; and it was also met with in abundance by the German +polar expedition of 1869-70 at Sabine Island on the east coast. No trace +of it has been found in Spitzbergen or Franz Joseph Land. As proved +by the discovery of fossil remains, it ranged during the Pleistocene +period over northern Siberia and the plains of Germany and France, its +bones occurring very generally in river deposits along with those of +the Reindeer, Mammoth, and Woolly Rhinoceros. It has also been found in +Pleistocene gravels in several parts of England, as Maidenhead, Bromley, +Freshfield near Bath, Barnwood near Gloucester, and also in the lower +brick-earth of the Thames valley at Crayford, Kent. + +It is gregarious in habit, assembling in herds of twenty or thirty head, +or, according to Hearne, sometimes eighty or a hundred, in which there +are seldom more than two or three full-grown males. The Musk-Ox runs with +considerable speed, notwithstanding the shortness of its legs. Major +H. W. Feilden, naturalist to the Arctic expedition of 1875, says: “No +person watching this animal in a state of nature could fail to see how +essentially ovine are its actions. When alarmed they gather together like +a flock of sheep herded by collie dog, and the way in which they pack +closely together and follow blindly the vacillating leadership of the old +ram is unquestionably sheep-like. When thoroughly frightened they take +to the hills, ascending precipitous slopes and scaling rocks with great +agility.” They feed chiefly on grass, but also on moss, lichens, and +tender shoots of the willow and pine. The female brings forth a single +young one in the end of May or beginning of June after a gestation of +nine months. According to Sir J. Richardson, “when this animal is fat +its flesh is well tasted, and resembles that of the Caribou, but has +a coarser grain. The flesh of the bulls is highly flavoured, and both +bulls and cows when lean smell strongly of musk, their flesh at the same +time being very dark and tough, and certainly far inferior to that of +any other ruminating animal existing in North America.” The carcase of +a Musk-Ox weighs, exclusive of fat, above 3 cwt. On this subject, Major +Feilden[247] says: “The cause of the disagreeable odour which frequently +taints the flesh of these animals has received no elucidation from my +observations. It does not appear to be confined to either sex, or to any +particular season of the year; for a young unweaned animal, killed at +its mother’s side and transferred within an hour to the stew-pans, was +as rank and objectionable as any. The flesh of some of these animals of +which I have partaken was dark, tender, and as well flavoured as that of +four-year old Southdown mutton.” + +Remains of two fossil species of this genus (_O. bombifrons_ and _O. +cavifrons_) have been described from Pleistocene beds in the United +States, the one from Kentucky and the other from the Arkansas River. Both +(if indeed they be valid species) appear closely allied to the living +form. + +_Bovine Section._—Horns present and of nearly equal size in both sexes; +in form rounded or angulated, placed on or near the vertex of the +skull, extending more or less outwards, and curving upwards near the +extremities; external surface comparatively smooth and never marked by +prominent transverse ridges or knobs. Muzzle broad, with large naked +muffle; nostrils lateral; no suborbital gland. Skull without any trace of +lachrymal fossa or fissure. Tail long and cylindrical; generally tufted +at the extremity, rarely hairy throughout. Males usually with a dewlap on +the throat. No foot-glands. Molar teeth extremely hypsodont; those of the +upper jaw with a nearly square cross-section, and a large accessory inner +column. + +The section is abundantly represented in the Palæarctic, Oriental, and +Ethiopian regions, with one Nearctic species and an outlying and aberrant +species in Celebes. + +_Bos._[248]—The whole of the species of Oxen were included by Linnæus in +the single genus _Bos_, and although the species have been distributed +by modern zoologists in several genera—such as _Anoa_, _Bubalus_, +_Bison_, _Poëphagus_, _Bibos_, and _Bos_—the characters by which they are +separated are so slight that it seems, on the whole, preferable to retain +the old genus in its original wide sense. Using then the term _Bos_ in +this sense, it will include all the representatives of the section—about +a dozen in number—and may be divided into several groups. + +The first group includes the Buffaloes (genus _Bubalus_), chiefly +characterised by their more or less flattened and angulated horns, which +incline upwards and backwards, with an inward curve towards their tips, +and are placed below the plane of the occiput, or vertex of the skull. +The premaxillæ reach to the nasals, and the vomer is peculiar in being +so much ossified as to join the posterior border of the palate. The back +has a distinct ridge in the region of the withers; and the forehead is +frequently convex. Oriental and Ethiopian region, and Celebes. + +The most generalised representative of this group is the small Anoa +(_B. depressicornis_) of Celebes, the type of the genus _Anoa_ or +_Probubalus_, which has the same cranial structure as in the more +typical Buffaloes, to the young of which (as was pointed out by the +late Professor Garrod) it presents a striking resemblance. Its colour +is black; and the short and prismatic horns are directed upwards from +the forehead. In the Pliocene Siwaliks of India there occur the remains +of larger Buffaloes (_B. occipitalis_ and _B. acuticornis_) closely +allied to the Anoa, but with longer and more distinctly angulated horns. +The still larger _B. platyceros_ of the last-named deposits, in which +the horns are wide-spreading and much flattened, appears to be in some +respects intermediate between the preceding and following forms. The +typical Indian Buffalo (_Bos buffelus_), which has been domesticated +over South-East Asia, Egypt, and Southern Europe, is, in the wild state, +a gigantic animal with enormous horns. These horns are longer, more +slender, and more outwardly directed in the female than in the male; +and in the former sex may have a length of more than 6 feet from base +to tip. They are widely separated at their bases, the forehead is very +convex, and the ears are not excessively large, and have no distinct +fringe. These Buffaloes frequent swampy and moist districts in several +parts of India, but it is in many instances difficult to decide whether +they belong to really wild or to feral races. Very large skulls, +specifically indistinguishable from those of the existing form, occur in +the Pleistocene deposits of the Narbada valley in India; while an allied, +if not specifically identical form, occurs in the Pliocene of the same +country. There is some doubt whether _B. antiquus_ of the Pleistocene of +Algeria is most nearly related to the Indian or to the African species. + +In Africa two species of Buffalo are recognised by Sir Victor +Brooke,[249] namely the large _B. caffer_, occurring typically at the +Cape, but said by this writer to range to Abyssinia, and the smaller +_B. pumilus_, which seems to have a very wide distribution. The skulls +of both these forms are shorter than in the Indian species, while the +horns are also shorter, much more curved inwardly, and more approximated +on the forehead. In the large typical form of _B. caffer_ from South +Africa the colour is black, the horns of the male are very thick, much +reflected, and closely approximated on the forehead, where they form +a helmet-like mass.[250] The large northern form described as _B. +æquinoctialis_ has the horns somewhat less thick, and thus approximates +to the so-called _B. pumilus_. + +The latter occurs typically in Western Africa, where it has also been +described as _B. brachyceros_. In the typical form the horns are thinner +and less reflected than in _B. caffer_, and in some specimens they are +more widely separated on the forehead, and are marked at their bases by +distinct rugæ. The colour is ruddy brown, inclining to rufous in one +specimen. The skulls of Buffaloes from West Africa, probably referable to +the form described as _B. centralis_, appear to connect _B. pumilus_ with +_B. caffer_, as shown by their larger size and the form of their horns; +so that further observations are required to show whether the smaller +form is really entitled to rank as a distinct species, or merely as a +well-marked local race. + +The second group comprises the Bisons, which are more nearly allied to +the true Oxen, having similar rounded horns, but the skull being less +massive, with a longer and more tapering frontal region, and a wider +frontal diameter. The superior part of the forehead is transversely +arched, the intercornual space elevated in the middle, the horns situated +below the plane of the occiput, and the orbits more or less prominent. +The premaxillæ do not extend upwards to reach the nasals. The Bisons +(Fig. 148) have the body covered with short, crisp, woolly hair, while on +the head and neck there is an abundance of much longer and darker hair, +which forms a mane concealing the eyes, ears, and the bases of the horns. +There is also a long beard beneath the chin; while a line of long hair +extends from the head nearly to the tail, the latter being tufted at the +extremity. The withers are much higher than the hind quarters, so that +there is a kind of hump at the shoulders. + +The group is represented by two species—the European and the American +Bison. The former is the _Bos bonasus_ of Linnæus, and is also identical +with the _Bos bison_ of Ray. The German name _Wisent_ is the equivalent +of the Greek _Bison_. The American species is the _Bos americanus_ of +Gmelin. Both species are closely allied, but the American Bison is +slightly the smaller animal of the two, and is shorter and weaker in +the hind quarters, with a smaller pelvis; its body is, however, more +massive in front; and the hair on the head, neck, and fore quarters is +longer and more luxuriant. A large bull American Bison, preserved in the +Museum at Washington, stands 5 feet 8 inches in height at the withers. +The European Bison appears to have been formerly abundant over a large +portion of Europe in the Pleistocene period—the fossil race described as +_B. priscus_ not being specifically distinct; but at the present day it +exists only in the primeval forests of Lithuania, Moldavia, Wallachia, +and the Caucasus, where it is artificially preserved. + +[Illustration: FIG. 148.—The American Bison (_Bos americanus_). After +Hornaday.] + +The American Bison formerly ranged over about one-third of the North +American continent. Thus, to quote from Mr. Hornaday,[251] “starting +almost at tide-water on the Atlantic coast, it extended across the +Alleghany mountain system to the prairies along the Mississippi, and +southward to the delta of that great system. Although the great plain +country of the West was the natural home of the species, where it +flourished most abundantly, it also wandered south across Texas to +the burning plains of North-Eastern Mexico, westward across the Rocky +Mountains into New Mexico, Utah, and Idaho, and northward across a +vast treeless waste to the bleak and inhospitable shores of the Great +Slave Lake itself.” In consequence of the settlement of the country by +Europeans the area inhabited by the Bison was gradually contracted, till +about 1840 one mighty herd occupied the centre of its former range. +The completion of the Union Pacific Railway in 1869 divided this great +herd into a southern and a northern division, the former comprising +a number of individuals estimated at nearly four millions, while the +latter contained about a million and a half. Before 1880 the southern +herd had, however, practically ceased to exist; while the same fate +overtook the northern one in 1883. In 1889 some twenty stragglers in +Texas represented the last of the southern herd; while there were a few +others in Colorado, Wyoming, Montana, and Dakota. A herd of some two +hundred wild individuals, derived from the northern herd, is preserved by +the United States Government in the Yellowstone National Park; and it is +believed that some five hundred of the race known as Wood-Bison exist in +British territory; but with these exceptions this magnificent species is +exterminated. The multitudes in which the American Bison formerly existed +are almost incredible; the prairies being absolutely black with them as +far as the eye could reach, and the numbers in the herds being, as we +have said, reckoned by millions. Mr. Hornaday even considers that the +whole of the game in South Africa was never equal to the number of Bison +on an equal area of the American prairies. + +[Illustration: FIG. 149.—The Yak (_Bos grunniens_), domestic variety.] + +An extinct Bison from the Pleistocene of Texas, known as _Bos latifrons_, +was probably the ancestor of the recent American species. + +The Yak (_Bos grunniens_) appears to be allied both to the Bisons and the +true Oxen, being distinguished from the former by the different position +occupied by the long hair, which forms a fringe investing the shoulders, +flanks, and thighs, and grows over the whole of the tail. In the skull +the orbits are less tubular, the forehead flatter, and the premaxillæ +less widely separated from the nasals. There is no distinct dewlap. +Wild Yaks inhabit the higher regions of Chinese Tibet and the region of +the Karakoram, as well as the more outlying parts of Ladak, such as the +Changchemo valley. Owing, however, to incessant pursuit those now found +within the territories of the Maharaja of Kashmir are stragglers from +Chinese Tibet. The height of the Yak is somewhat lower than that of the +larger domestic cattle. The colour of the wild race is black, tending +to brown on the flanks; but many of the tame breeds which have been +crossed with ordinary cattle have more or less white (Fig. 149), and it +is the white tails of these half-breeds that are so esteemed in India as +“chowries.” Yaks are exceedingly intolerant of heat, and the wild ones +always live at very great elevations. Tame Yaks are extensively used as +beasts of burden in Tibet, where they are extremely valuable in crossing +the high and desolate wastes of that region; they have, however, the +great drawback that they refuse to eat corn, so that in districts where +there is no grass it is frequently necessary to make forced marches +with wearied beasts in order to prevent them (and thus the whole party) +perishing from starvation. + +The skull of an extinct species from the Pliocene of Northern India, +described as _Bos sivalensis_, appears to indicate a species allied to +the Yak. + +With the Bibovine group we come to the consideration of three Oriental +species which connect the preceding forms with the typical Oxen. The +three species are the Gaur (_B. gaurus_) the Gayal (_B. frontalis_, +Fig. 150) of India, and the Banteng (_B. sondaicus_) of Burma, Java, +Bali, and Lambok. In this group, as in the true Oxen, there are thirteen +pairs of ribs, against fourteen in the Bisons. All the three species +are characterised by the great height of the spines of the anterior +dorsal vertebræ, causing a prominent ridge down the back. The horns, +which are of a greenish colour in the Gaur, are somewhat flattened, and +after running outwards are directed upwards instead of backwards; they +occupy the vertex of the skull. The frontals are more or less concave, +the premaxillæ do not join the nasals, and the occipital aspect of +the skull is characterised by the deep incisions made by the temporal +fossæ. The lower part of the legs is white (Fig. 150), and the hoofs are +comparatively small and pointed. The Gaur (_B. gaurus_) is the largest +of the three species, and inhabits all the large forests of India from +near Cape Comorin to the foot of the Himalaya; it is commonly known +to sportsmen as the Indian Bison. It stands fully 6 feet in height +at the withers, which are much elevated; and since the whole back is +arched the line from the nose to the root of the tail forms an almost +continuous curve. The most characteristic feature of the animal is, +however, the large and convex intercornual frontal crest, which curves +forward, and thus gives a concave profile to this part of the skull. As +a rule the Gaur prefers hilly regions, although it is sometimes met with +on the flat. It is very shy and readily frightened; and it has never +been domesticated. The Gayal, or Mithan, of which a figure is given in +woodcut 150, is at once distinguished from the Gaur by the straight line +between the horns (which are black in colour), owing to the absence of +the intercornual crest of the latter. The horns are also shorter, more +rounded, and less curved. In the Indian Museum, Calcutta, there are, +however, skulls which are to a great extent intermediate between those +of typical Gaurs and those of typical Gayals, but these may belong to +hybrids. The Gayal occurs in Assam, Chittagong, and adjacent districts, +but it appears that these animals exist in a semi-domesticated condition, +no wild race being known to Europeans, although it is probable that such +may exist in the unexplored Mishmi Hills. + +[Illustration: FIG. 150.—The Gayal (_Bos frontalis_). From Sclater, _List +of Animals in Zoological Society’s Gardens_, 1883.] + +The Banteng (_B. sondaicus_) is a smaller and lighter built animal +than either of the preceding, with a longer and sharper head, and more +rounded and slender horns. The dorsal ridge is, moreover, but slightly +developed; while the bright dun colour of the body of the female readily +distinguishes it from the darker hue of the Gaur and Gayal. + +A fossil skull from the Pleistocene deposits of the Narbada valley, +India, described as _Bos palæogaurus_, is believed to indicate a species +nearly allied to the Gaur, if indeed it be specifically distinct. + +The true Oxen, or Taurine group, are now represented solely by _Bos +taurus_ and _Bos indicus_. Both of these species are now known only +by domesticated races, unless the herds of the former preserved at +Chillingham and some other British parks are the survivors of an original +wild race. The dorsal ridge of the Bibovine group is here wanting; +the horns are rounded, with their extremities directed backwards, and +are placed at the extreme vertex of the skull; while the long frontal +region is nearly flat; the temporal fossæ scarcely intrude upon the +occipital aspect of the skull; and the premaxillæ reach the nasals. The +hoofs are large and rounded. It is known that wild Oxen were abundant +in the forests of Europe at the time of Julius Cæsar, by whom they were +described as the Urus, equal to the German Aurochs; and the large skulls +found in turbary and Pleistocene deposits, and described under the name +of _Bos primigenius_, can only be regarded as having belonged to the +large original race of _B. taurus_, of which it has been thought the +Chillingham cattle are smaller descendants.[252] The subfossil skulls +described as _B. longifrons_ and _B. frontosus_ must also be looked upon +as referable to smaller races of the same species. That the domestic +cattle of Europe are descendants from the various races of the same +original species there can be no doubt, but in the case of the humped +cattle of India (_B. indicus_) it is quite probable that their origin +may be, at least in part, different. The extinct _Bos namadicus_, of the +Pleistocene deposits of India, was a species with the general characters +of the Taurine group, but with an inclination to a flattening of the +horns, and with an approximation to a Bibovine type of occiput, as well +as with the separation of the premaxillæ from the nasals. + +The earliest representatives of this group occur in the Pliocene of the +Siwalik Hills in Northern India. One of these species (_B. planifrons_) +appears to be allied to _B. namadicus_; but the other (_B. acutifrons_) +was a gigantic species characterised by the sharp median angulation of +the frontal region, and the pyriform section of the enormous horn-cores. + +The extinct _B. elatus_, from the Upper Pliocene of France and Italy, +is the representative of a generalised type, which may be known as the +Leptobovine group. The males had rounded horn-cores widely separated at +their bases, and placed low down on the forehead. The females (which have +been described as _Leptobos_) were often or always hornless. The limbs +were unusually slender. This group also occurs in the Pliocene of the +Siwalik Hills. + + +_Suborder_ PERISSODACTYLA. + +This is a perfectly well-defined group of Ungulate mammals, represented +in the actual fauna of the world by only three distinct types or +families—the Tapirs, the Rhinoceroses, and the Horses—poor in genera +and species, and (except in the case of the two domesticated species of +_Equus_, which have been largely multiplied and diffused by man’s agency) +not generally numerous in individuals, though widely scattered over the +earth’s surface. Palæontological records, however, show very clearly that +these are but the surviving remnants of a very extensive and much-varied +assemblage of animals, which flourished upon the earth through the +Tertiary geological period, and which, if it could be reconstructed in +its entirety, would not only show members filling up structurally the +intervals between the existing apparently isolated forms, but would also +show several marked lines of specialisation which have become extinct +without leaving any direct successors. + +[Illustration: FIG. 151.—Bones of right fore foot of existing +Perissodactyles. A, Tapir (_Tapirus indicus_), × ⅕; B, Rhinoceros +(_Rhinoceros sumatrensis_), × ⅙; C, Horse (_Equus caballus_), × ⅛. _U_, +ulna; _R_, radius; _c_, cuneiform; _l_, lunar; _s_, scaphoid; _u_, +unciform; _m_, magnum; _td_, trapezoid; _tm_, trapezium.—From Flower, +_Osteology of Mammalia_.] + +The following are the principal characters distinguishing them from +the Artiodactyla. Premolar and molar teeth in continuous series, with +massive, quadrate, transversely ridged or complex crowns,—the posterior +premolars often resembling the true molars in size and structure. Crown +of the last lower molar commonly bilobed, and if a third lobe is present +in this tooth it is wanting in the last lower milk-molar. Dorso-lumbar +vertebræ never fewer than twenty-two, usually twenty-three in the +existing species. Nasal bones expanded posteriorly. An alisphenoid +canal. Femur with a third trochanter.[253] The middle or third digit on +both fore and hind feet larger than any of the others, and symmetrical +in itself, the free border of the ungual phalanx being evenly rounded +(see Fig. 151). This may be the only functional toe, or the second and +fourth may be subequally developed on each side of it. In the Tapirs +and many extinct forms, the fifth toe also remains on the fore limb, +but its presence does not interfere with the symmetrical arrangement of +the remainder of the foot around the median line of the third or middle +digit. Traces of a hallux have only been found in some extremely ancient +and primitive forms. The astragalus has a pulley-like surface above +for articulation with the tibia, but its distal surface is flattened +and unites to a much greater extent with the navicular than with the +cuboid, which bone is of comparatively less importance than in the +Artiodactyla. The calcaneum does not articulate with the lower or distal +extremity of the fibula. The stomach is always simple, the cæcum is large +and capacious, the placenta diffused, and the mammæ are inguinal. The +gall-bladder is invariably absent. + +As regards the dentition, the whole of the premolar series may be +preceded by milk-teeth; and it has been demonstrated in _Rhinoceros_ +that when there is no displacement of the first cheek-tooth that tooth +is a persistent milk-molar; the same condition apparently holding +good in _Palæotherium._ This feature indicates considerable dental +specialisation, the milk-molars, according to the theory generally +accepted by the leading English zoologists, being the acquired, and the +premolars the original series. Another peculiar feature of the dentition +of the Perissodactyla, very rarely met with among the Artiodactyla, +is that the premolars tend to resemble the true molars; this feature +occurring in all the existing genera, although not found in the earlier +generalised types. The cheek-teeth of all the members of the suborder +are primarily constructed on some modification of what is known as the +lophodont plan. Thus the upper molars (Fig. 155, p. 375) have an outer +antero-posterior wall from which proceed two transverse ridges, formed +by the coalescence of the primitive inner and outer columns, towards +the inner aspect of the crown; while in the lower molars there may be +either two simple transverse ridges, or these ridges may be curved into +crescents, coming into contact with one another at their extremities. +Those forms having brachydont teeth show this plan of structure in its +simplest modification; but in cases, as in the Horse, where the teeth +assume an extremely hypsodont form, the original plan is so obscured by +infoldings of the enamel that it can only be traced with difficulty. + +At the present day the Perissodactyla are sharply differentiated into +Horses, Tapirs, and Rhinoceroses, but the knowledge already gained of +the extinct representatives of the suborder shows such a close alliance +between these groups that it is exceedingly difficult to make any +satisfactory classification of the whole. This is of course exactly what +might have been expected; and the same would doubtless be the case with +all other groups if we knew as much of their past history as we do of +that of the Perissodactyles. + +The detailed account of the anatomy of the Horse given in the sequel will +afford much information as to the general structure of the members of the +suborder. + + +_Family_ TAPIRIDÆ. + +Both upper and lower cheek-teeth brachydont and simply bilophodont; +hinder premolars as complex as the molars; last lower molar without third +lobe; first upper cheek-tooth with a milk-predecessor.[254] Outer columns +of upper molars conical. Four digits in the manus, and three in the pes. + +_Tapirus._[255]—Dentition _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₃, _m_ ³⁄₃; total 42. +Of the upper incisors, the first and second are nearly equal, with short, +broad crowns; the third is large and conical, considerably larger than +the canine, which is separated from it by an interval. Lower incisors +diminishing in size from the first to the third; the canine, which is +in contact with the third incisor, large and conical, working against +(and behind) the canine-like third upper incisor. In both jaws there +is a diastema between the canines and the commencement of the teeth of +the cheek-series, which are all in contact. First upper premolar with a +triangular crown, narrow in front owing to the absence of the anterior +inner cusp. The other upper premolars and molars all formed on the same +plan and of nearly the same size, with four roots and quadrate crowns, +rather wider transversely than from before backwards, each having four +cusps, connected by a pair of transverse ridges, anterior and posterior. +The first lower premolar compressed in front; the others composed of a +simple pair of transverse crests, with a small anterior and posterior +circular ridge. + +Skull elevated and compressed. Orbit and temporal fossa widely +continuous, there being no true postorbital process from the frontal +bone. Anterior narial apertures very large, and extending high on the +face between the orbits; nasal bones short, elevated, triangular, and +pointed in front. Vertebræ: C 7, D 18, L 5, S 6, C about 12. Limbs short +and stout. Forefeet with four toes, having distinct hoofs: the first +is absent, the third the longest, the second and fourth nearly equal, +the fifth the shortest and scarcely reaching the ground in the ordinary +standing position. Hind feet with the typical Perissodactyle arrangement +of three toes,—the middle one being the largest, the two others nearly +equal. Nose and upper lip elongated into a flexible, mobile snout or +short proboscis, near the end of which the nostrils are situated. Eyes +rather small. Ears of moderate size, ovate, erect. Tail very short. Skin +thick and but scantily covered with hair. + +The existing species of Tapir may be grouped into two sections, the +distinctive characters of which are only recognisable in the skeleton. +(A) With a great anterior prolongation of the ossification of the nasal +septum (mesethmoid), extending in the adult far beyond the nasal bones, +and supported and embraced at the base by ascending plates from the +maxillæ (genus _Elasmognathus_, Gill). Two species, both from Central +America, _Tapirus bairdi_ and _T. dowi_. The former is found in Mexico, +Honduras, Nicaragua, Costa Rica, and Panama; the latter in Guatemala, +Nicaragua, and Costa Rica. (B) With ossification of the septum not +extending farther forward than the nasal bones (_Tapirus_ proper). +Three species, _T. indicus_, the largest of the genus, from the Malay +Peninsula (as far north as Tavoy and Mergui), Sumatra, and Borneo, +distinguished by its peculiar coloration, the head, neck, fore and hind +limbs, being glossy black, and the intermediate part of the body white; +_T. americanus_ (_T. terrestris_, Linn.), the common Tapir of the forests +and lowlands of Brazil and Paraguay (Fig. 152); and _T. roulini_, the +Pinchaque Tapir of the high regions of the Andes. All the American +species are of a nearly uniform dark brown or blackish colour when adult; +but it is a curious circumstance that when young (and in this the Malay +species conforms with the others) they are conspicuously marked with +spots and longitudinal stripes of white or fawn colour on a darker ground. + +The habits of all the kinds of Tapirs appear to be very similar. They are +solitary, nocturnal, shy, and inoffensive, chiefly frequenting the depths +of shady forests and the neighbourhood of water, to which they frequently +resort for the purpose of bathing, and in which they often take refuge +when pursued. They feed on various vegetable substances, as shoots of +trees and bushes, buds, and leaves. They are hunted by the natives of the +lands in which they live for the sake of their hides and flesh. + +The singular fact of the existence of so closely allied animals as the +Malayan and the American Tapirs in such distant regions of the earth, +and in no intervening places, is accounted for by what is known of +the geological history of the race; for the Tapirs must once have had +a very wide distribution. There is no proof of their having lived in +the Eocene epoch, but in deposits of Miocene and Pliocene date remains +undistinguishable generically from the modern Tapirs, and described as +_T. priscus_, _T. arvernensis_, etc., have been found in France, Germany, +and in the Red Crag of Suffolk. Tapirs appear, however, to have become +extinct in Europe before the Pleistocene period, since none of their +bones or teeth have been found in any of the caverns or alluvial deposits +in which those of Elephants, Rhinoceroses, and Hippopotamuses occur in +abundance; but in other regions their distribution at this age was far +wider than at present, as they are known to have extended eastward to +China (_T. sinensis_, Owen) and westwards over the greater part of the +southern United States of America, from South Carolina to California. +Lund also distinguished two species or varieties from the caves of +Brazil, one of which appears identical with _T. americanus_. Thus we +have no difficulty in tracing the common origin in the Miocene Tapirs of +Europe of the now widely separated American and Asiatic species. It is, +moreover, interesting to observe how very slight an amount of variation +has taken place in forms isolated during such an enormous period of time. + +[Illustration: FIG. 152.—The American Tapir (_Tapirus americanus_).] + +The anatomy of the soft parts of the Tapirs[256] conforms to the general +Perissodactyle type, as exemplified in the Rhinoceros and the Horse, +although on the whole (as might have been expected) presenting a closer +resemblance to the former. _T. americanus_ differs from _T. indicus_ +by the absence, or at any rate the less development, of the intestinal +valvulæ conniventes, the presence of a moderator band in the heart, +the shape of the glans penis, and the more elongated cæcum, which is +sacculated by four distinct longitudinal fibrous bands. The convolutions +of the hemispheres of the brain of the Tapirs are simpler than in other +Perissodactyles, thus tending to confirm the inferences which may +be drawn from the skeleton and teeth as to the comparatively low or +generalised organisation of these animals. + +_Palæotapirus._—This name has been applied to an imperfectly known form +from the Upper Eocene Phosphorites of Central France, which is regarded +by Dr. Filhol as referable to this family. + + +_Family_ LOPHIODONTIDÆ. + +Molars brachydont and bilophodont, those of the lower jaw with either +straight or imperfectly crescentoid ridges; premolars smaller and usually +simpler than the molars; last lower molar generally with a third lobe. +Outer columns of upper molars conical or flattened. Digits usually as in +the preceding family. + +[Illustration: FIG. 153.—Right side of skull of _Hyracotherium +leporinum_, from the London Clay. ½ natural size. (After Owen.) 3, +Occiput; 7, sagittal crest; 11, frontals; 15, nasals; 21, maxilla; 22, +premaxilla; _d_, mandibular condyle; _a_, aperture of facial nerve; _p_ +1-4, premolars; _m_ 1-3, molars.] + +This family includes a number of more or less imperfectly known +forms, all of which are extinct and apparently confined to the Eocene +period, and ranging from the size of a Rabbit to that of a Rhinoceros. +Although some of these appear to have died out without giving rise to +more specialised forms, it is probable that this family contained the +ancestral types from which most or all of the modern Perissodactyles +have been derived. Only very brief mention can be made here of some +of the leading genera. _Lophiodon_, of the Middle and Upper Eocene of +Europe, with the dental formula, _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃, +includes the largest representatives of the family, and is generally +regarded as a stock which has died out without giving rise to later +forms. The ridges of the lower molars are straight, and the last of these +teeth has a third lobe; while the second transverse ridge of the last +upper premolar is usually incomplete; the outer columns of the upper +molars are flattened, as in the next genus. _Hyrachyus_, of the Upper +Eocene of the United States, and probably also occurring in the French +Eocenes, is an allied genus, with four premolars and no third lobe to +the last lower molar; the fourth upper premolar having the two ridges +uniting internally to form a crescent. This genus has been regarded as +the ancestor of the Rhinocerotic _Hyracodon_. The genus _Hyracotherium_ +was established in 1839 by Owen for a small animal no larger than a +Hare, the skull of which was found in the London Clay at Herne Bay. +A more nearly perfect specimen, apparently of the same species, was +afterwards (in 1857) described under the name of _Pliolophus vulpiceps_, +of which the skull is figured in the accompanying woodcut. Other forms +referable to the same genus have been obtained from the Wasatch Eocene +of the United States, and were described by Professor Marsh under the +name of _Eohippus_. There were four premolars, the fourth being unlike +the molars, and in the upper jaw having only one inner cusp. The upper +molars are of the general type of those of _Lophiodon_, but have conical +outer columns, and the anterior transverse ridge imperfect, while +the ridges of the lower molars are crescentoid. _Systemodon_ differs +from _Hyracotherium_ by the absence of a diastema between the first +and second premolars; it occurs in the Wasatch Lower Eocene of the +United States. In _Pachynolophus_ (_Lophiotherium_, _Orotherium_, or +_Orohippus_), which is common to the Middle and Upper Eocene of Europe +and the Bridger Eocene of North America, the outer columns of the upper +molars are flattened, and in some cases, at least, the last premolar +resembles the molars, that of the upper jaw having two inner cusps.[257] +This genus, indeed, so closely connects _Hyracotherium_ with the genera +_Epihippus_ and _Anchilophus_ as to show that the distinction between +the _Lophiodontidæ_ and _Palæotheriidæ_ is really an arbitrary one. +_Epihippus_, of the Upper Eocene of the United States, has both the third +and fourth upper premolars as complex in the molars, and is distinguished +from _Anchilophus_ by the lower cusps and more imperfect transverse +ridges of these teeth. The so-called _Orohippus agilis_ belongs to this +genus. _Isectolophus_ is another American Eocene genus which may be +provisionally placed in this family; it is regarded by Professors Scott +and Osborn as connecting _Systemodon_ with the _Tapiridæ_; the fourth +and probably the third upper premolar approximating in structure to the +molars; the upper molars have conical outer columns. _Helaletes_ is +another closely allied form, with similar premolars, but with the outer +columns of the upper molars flattened. + +[Illustration: FIG. 154.—Restoration of _Palæotherium_ (Upper Eocene). +After Cuvier.] + + +_Family_ PALÆOTHERIIDÆ. + +[Illustration: FIG. 155.—A half-worn right upper molar of _Palæotherium +magnum_. (After Owen.) _f_, _f_, External surfaces of outer columns; +_a_, postero-external column (metacone); _b_, antero-external column +(paracone); _c_, postero-internal column (hypocone); _d_, antero-internal +column (protocone); _i_, anterior intermediate column (protoconule); _e_, +median valley; _g_, posterior valley.] + +Molars (Fig. 155) brachydont, with the valleys between the ridges never +filled with cement; upper premolars either simpler than or as complex +as the molars; lower molars with crescentoid ridges, and the last of +the series with or without a third lobe. Outer columns of upper molars +flattened. Orbit (at least usually) confluent with temporal fossa. Three +digits on each foot. This family includes extinct genera ranging from +the Middle and Upper Eocene to the Miocene, and passes so gradually into +the following one that the maintenance of the two can only be supported +on the ground of convenience. The typical genus, _Palæotherium_, was +made known to science in the early part of the present century by +Cuvier, who restored the skeleton (Fig. 154) with a short neck like that +of the Tapirs, although it has been subsequently found that the neck +was considerably longer. This genus (which may be taken to include +_Paloplotherium_) ranges from the Middle to the Upper Eocene of Europe, +and usually has the full typical dentition, although the first premolar +may disappear. The last lower molar has a third lobe; and in the typical +forms the last premolar is as complex as the molars, the diastema is +short, and the canines are not large. In other forms, however, the +hinder ridge of the fourth upper premolar may be aborted. The first +upper cheek-tooth is generally a well-developed tooth, which may have +a deciduous predecessor. _Anchilophus_, of the Upper Eocene of Europe, +and _Anchitherium_, of the Miocene of Europe and North America, connect +the preceding forms with the _Equidæ_. In the latter genus there is the +full number of teeth, the last lower molar has almost completely lost +the third lobe of _Anchilophus_, and the surfaces of the two outer lobes +of the upper molars (Figs. 157, 158) lack the median vertical ridges of +that genus. In the American species of _Anchitherium_ (which have been +described as _Mesohippus_ and _Miohippus_) the lateral digits are larger +than in the European Middle Miocene _Anchitherium aurelianense_; a mere +splint represents the fifth metacarpal, and the meso- and ento-cuneiform +of the tarsus do not unite as they do in the latter. + + +_Family_ EQUIDÆ. + +Molars hypsodont, with the outer columns of the upper ones flattened, the +valleys completely filled with cement, and the enamel thrown into folds +and plications; upper premolars as complex as molars, which they slightly +exceed in size; ridges of lower molars crescentoid, and complicated by +enamel-foldings; no distinct third lobe to last lower molar; summits of +incisors with a central infolding of enamel. Orbit completely surrounded +by bone. Digits three or one, but in the former case the median one is +alone of functional importance; ulna and fibula incomplete; meso- and +ento-cuneiform of tarsus united. + +Such are the leading characters which serve to distinguish the existing +Horses and their nearest fossil allies from the _Palæotheriidæ_. The +Horse, as being the best known of the Perissodactyle Ungulates, is +selected for a somewhat detailed description; but before proceeding +to this it will be advisable to take a brief survey of the relations +of the _Equidæ_ to the extinct forms already noticed, and also of the +modifications of the family at present existing. + +The earliest form which can be certainly included in this line of descent +is the American Lower Eocene genus _Phenacodus_ (noticed below under the +head of the suborder Condylarthra), in which there were five complete +digits to the feet. From this form there is but a step to _Systemodon_ +and _Hyracotherium_, in which the functional digits of the manus were +reduced to four, as in _Pachynolophus_ (Fig. 156, _a_), although one +species retained a rudiment of the metacarpal of the pollex. + +[Illustration: FIG. 156.—Successive stages of modification of the feet +of extinct forms of Horse-like animals (chiefly from Marsh), showing +gradual reduction of the outer and enlargement of the middle toe (III). +_a_, _Pachynolophus_ (Eocene); _b_, _Anchitherium_ (Early Miocene); _c_, +_Anchitherium_ (Late Miocene); _d_, _Hipparion_ (Pliocene); _e_, _Equus_ +(Pleistocene).] + +The transition from these animals of the Eocene period to the Horses of +modern times has been accompanied by a gradual increase in size. The +diminutive _Hyracotherium_ of the Lower, and _Pachynolophus_ of the +Middle and Upper Eocene were succeeded in the Miocene period by the +forms to which the name of _Anchitherium_ has been given, of the size of +sheep; these again in Pliocene times by _Hipparion_ and _Protohippus_, as +large as the modern donkeys; and it is mainly in the Pleistocene period +that _Equidæ_ occur which approach in size the existing Horse. Important +structural modifications have also taken place, with corresponding +changes in the mode of life of the animal. Thus the neck has become +elongated, the skull altered in form, the teeth greatly modified, and +the limbs have undergone remarkable changes. The last two require to be +described more in detail. + +[Illustration: FIG. 157.—_a_, Grinding surface of unworn molar tooth +of _Anchitherium_; _b_, corresponding surface of unworn molar of young +Horse; _c_, the same tooth after it has been some time in use. The +uncoloured portions are the dentine or ivory, the shaded parts the +cement filling the cavities and surrounding the exterior. The black line +separating these two structures is the enamel or hardest constituent of +the tooth.] + +The teeth in the Eocene forms had, as mentioned above, the characteristic +number of forty-four. This number has been retained throughout the +series, at least theoretically; but one tooth on either side of each jaw, +the anterior premolar, which in all the Eocene and Miocene species was +well developed, persisting through the lifetime of the animal, is in all +modern Horses rudimentary, functionless, and generally lost at an early +period of life, evidently passing through a stage which must soon lead +to its complete disappearance. The canines have also greatly diminished +in size, and are rarely present in the female sex, so that practically +a very large number of adult Horses of the present day have eight teeth +less than the number possessed by their predecessors. The diastema or +interval between the incisor and premolar teeth (of essential importance +in the domesticated Horse to his master, as without it there would be no +room for inserting the special instrument of subjugation to his commands, +the bit) already existed in the earliest known forms, but has gradually +increased in length. The incisors have undergone in comparatively recent +times that curious change producing the structure more fully described +hereafter, which distinguishes the Horse’s incisors from those of all +other known animals, with the exception of the extinct _Macrauchenia_. +Lastly, the molars have undergone a remarkable series of modifications, +much resembling in principle those that have taken place in several other +groups of herbivorous animals. Distinctions in form which existed between +the premolars, at least in the anterior part of the series, and the true +molars have gradually disappeared, the teeth becoming all very uniform +in the shape and structure of their grinding surface. The crowns of all +these teeth in the early forms were very short (see Fig. 158, _a_); there +was a distinct constriction, or neck, between the crown and roots; and +when the tooth was developing, as soon as the neck once rose fairly above +the alveolar margin, the tooth remained permanently in this position. +The term “brachydont” expresses this condition of teeth, the mode of +growth of which may be illustrated by those of man. The free surface had +two nearly transverse curved ridges, with valleys between (Fig. 157, +_a_); but the valleys were shallow and had no deposit of cement filling +them, the whole exposed surface of the unworn tooth being formed of +enamel. When the ridges became worn down the dentine of the interior was +exposed, forming islands surrounded by enamel. With the progress of time +the crowns of the teeth gradually became longer, the valleys deeper, +and the ridges not only more elevated but more curved and complex in +arrangement. To give support to these high ridges and save them from +breaking in use, the valleys or cavities between them became filled up to +the top with cement, and as the crown wore down an admirable grinding +surface consisting of patches and islands of the two softer substances, +dentine and cement, separated by variously reduplicated and contorted +lines of intensely hard enamel, resulted (Fig. 157, _c_). The crown +continued lengthening until in the modern Horses it has assumed the form +called “hypsodont” (Fig. 158, _b_). Instead of contracting into a neck, +and forming roots, its sides continue parallel for a considerable depth +in the socket, and as the surface wears away, the whole tooth slowly +pushes up, and maintains the grinding edge constantly at the same level +above the alveolus, much as in the perpetually growing Rodent’s teeth. +But in existing Horses there is still a limit to the growth of the +molar. After a length is attained which in normal conditions supplies +sufficient grinding surface for the lifetime of the animal, a neck and +roots are formed, and the tooth is reduced to the condition of that of +the brachydont ancestor. It is perfectly clear that this lengthening +of the crown adds greatly to the power of the teeth as organs of +mastication, and enables the animals in which it has taken place to find +their sustenance among the comparatively dry and harsh herbage of the +open plains, instead of being limited to the more succulent vegetable +productions of the marshes and forests in which their predecessors +probably dwelt. + +[Illustration: FIG. 158.—_a_, Outer view of second upper molar teeth +of _Anchitherium_ (brachydont form); _b_, corresponding tooth of Horse +(hypsodont form).] + +The modifications of the limbs which took place _pari passu_ with those +of the teeth must have been associated with increased speed, especially +over firm and unyielding ground. Short, stout legs, and broad feet, with +numerous toes, spreading apart from each other when the weight of the +creature is borne on them, are sufficiently well adapted for plodding +deliberately over marshy and yielding surfaces, and the Tapirs and the +Rhinoceroses, which in the structure of the limbs have altered but little +from the primitive Eocene forms, still haunt the borders of streams and +lakes and the shady depths of the forests, as was probably the habit +of their ancient representatives, while the Horses are all inhabitants +of the open plains, for life in which their whole organisation is in +the most eminent degree adapted. The length and mobility of the neck, +position of the eye and ear, and great development of the organ of smell, +give them ample means of becoming aware of the approach of enemies, +while the length of their limbs, the angles the different segments form +with each other, and especially the combination of firmness, stability, +and lightness in the reduction of all the toes to a single one, upon +which the whole weight of the body and all the muscular power are +concentrated, give them speed and endurance surpassing that of almost any +other animal. When surprised, however, they are by no means helpless, +both fore and hind feet becoming at need powerful weapons of defence. + +If we were not so habituated to the sight of the Horse as hardly ever +to consider its structure, we should greatly marvel at being told of a +mammal so strangely constructed that it had but a single toe on each +extremity, on the end of the nail of which it walked or galloped. Such +a conformation is without a parallel in the vertebrate series, and is +one of the most remarkable instances of specialisation, or deviation +from the usual type, in accordance with particular conditions of life. +It is clear, both from the structure of the foot itself, and also by an +examination of the intermediate forms, that this toe corresponds to the +middle or third digit of the complete typical or pentadactyle foot; and +there is very strong evidence to show that by a gradual concentration of +all the power of the limb upon this toe, and the concurrent dwindling +away and final disappearance of all the others, the present condition of +the Horse’s foot has been produced. + +_Protohippus._[258]—In this Lower Pliocene North American genus (also +described as _Merychippus_) the cheek-teeth resemble those of the +generalised species of _Equus_, but have shorter crowns; while the +milk-molars approximate to the permanent molars of _Anchitherium_. Each +foot has three digits. + +[Illustration: FIG. 159.—Three right upper cheek-teeth of _Hipparion_. +_a_, Antero-external column; _b_, postero-external column; _c_, +postero-internal column, or posterior pillar; _d_, antero-internal +column, or anterior pillar; _f_, posterior intermediate column; _i_, +anterior intermediate column. (From the _Palæontologia Indica_.)] + +_Hipparion._[259]—Upper cheek-teeth (Fig. 159), with the antero-internal +column, or anterior pillar as it may be conveniently termed in this +family, detached throughout the greater part of its height from the +adjacent column. Either a single or three digits in each foot. First +upper premolar large and persistent. This genus was very widely +distributed in the Pliocene, occurring in Europe, Asia, and North +America. In the typical European forms, and also in those of North +America, there were three digits in the feet (Fig. 156, _d_); but in +the Indian _H. antilopinum_ (separated by Cope as _Hippodactylus_) the +lateral digits seem to have disappeared. There is some doubt whether or +no _Hipparion_ should occupy a place in the direct ancestry of the Horse, +and Professor Cope suggests that while in America the intermediate place +between _Anchitherium_ and _Equus_ was held by _Protohippus_, in Europe +the same position was occupied by _Hipparion_—a view which involves the +dual origin of the Horses of the New and Old Worlds. + +_Equus._[260]—Upper cheek-teeth with the anterior pillar (except in +a very early stage of wear) joined by a narrow neck to the adjacent +column (Fig. 157, _c_). Each foot with a single complete digit, but with +remnants of the proximal portions of the second and fourth metapodials +(Fig. 156, _e_); some extinct forms having claw-like rudiments of the +terminal phalangeals of the lateral digits. First upper premolar very +small or altogether absent in existing species, but in some fossil +species larger and persistent; first lower premolar only occasionally +developed in some fossil forms. Ears long. Tail long, with long hairs +either at the end or throughout. A callosity on the inner side of the +fore limb above the carpus. + +_Fossil Species._—In the Pleistocene Horses of South America described +as _Hippidium_, as well as in the closely allied ones from North America +for which the name _Pliohippus_ has been proposed, the upper molars +are shorter and more curved than in the existing species, while their +anterior pillar is not longer antero-posteriorly than in _Hipparion_; +the lateral claw-like hoofs persisting. Some of the European Pliocene +species (like _E. stenonis_) agree with these species in the form of +the grinding surface of the anterior pillar of the upper molars. In one +of the species from the Lower Pliocene of India (_E. sivalensis_)—which +was a contemporary of _Hipparion_—and in all the existing species, the +grinding surface of the pillar in question is greatly elongated in the +antero-posterior direction, as in Fig. 157, _c_. + +Fossil remains of Horses are found abundantly in deposits of the most +recent geological age in almost every part in America, from Eschscholtz +Bay in the north to Patagonia in the south. In that continent, however, +they became quite extinct, and no Horses, either wild or domesticated, +existed there at the time of the Spanish conquest, which is the more +remarkable as, when introduced from Europe, the Horses that ran wild +proved by their rapid multiplication in the plains of South America +and Texas that the climate, food, and other circumstances were highly +favourable for their existence. The former great abundance of _Equidæ_ +in America, their complete extinction, and their perfect acclimatisation +when reintroduced by man, form curious but as yet unsolved problems in +geographical distribution. + +_Existing Species._—The existing species of the genus are the following:— + +The Horse, _Equus caballus_, is distinguished from the others by the long +hairs of the tail being more abundant and growing quite from the base as +well as the end and sides, and also by possessing a small bare callosity +on the inner side of the hind leg, just below the “hock” or heel joint, +in addition to the one on the inner side of the fore limb above the +carpus, common to all the genus. The mane is also longer and more +flowing, and the ears are shorter, the limbs longer, the hoofs broader, +and the head smaller. + +Though the existing Horses are not usually marked in any definite manner, +or only irregularly dappled, or spotted with light surrounded by a darker +ring, many examples are met with showing a dark median dorsal streak +like that found in all the other members of the genus, and even with +dark stripes on the shoulders and legs indicating “the probability of +the descent of all the existing races from a single dun-coloured, more +or less striped, primitive stock, to which our horses still occasionally +revert.”[261] + +In Europe wild Horses were extremely abundant in the Neolithic or +polished-stone period. Judging from the quantity of their remains +found associated with those of the men of that time, the chase of +these animals must have been among man’s chief occupations, and they +must have furnished him with one of his most important food supplies. +The characters of the bones preserved, and certain rude but graphic +representations carved on bones or reindeers’ antlers, enable us to know +that these Horses were rather small in size, and heavy in build, with +large heads and rough shaggy manes and tails, much like, in fact, the +present wild horses of the steppes of the south of Russia. They were +domesticated by the inhabitants of Europe before the dawn of history, but +it is doubtful whether the majority of the animals now existing on the +Continent are derived directly from them, as it is more probable that +they are descendants from Horses imported through Greece and Italy from +Asia, derived from a still earlier domestication, followed by gradual +improvement through long-continued attention bestowed on their breeding +and training. Horses are now diffused by the agency of man throughout +almost the whole of the inhabited parts of the globe, and the great +modifications they have undergone in consequence of domestication and +selective breeding are well exemplified by comparing such extreme forms +as the Shetland pony, dwarfed by uncongenial climate, the thoroughbred +racer, and the London dray-horse. In Australia, as in America, horses +imported by the European settlers have escaped into the unreclaimed +lands, and multiplied to a prodigious extent, roaming in vast herds over +the plains where no hoofed animal ever trod before. + +A wild Horse from Central Asia, named _E. prezevalskii_,[262] is +described as having callosities on both limbs and broad hoofs like _E. +caballus_; but the long hairs of the tail do not begin until about half +way down its length. It also differs from _E. caballus_ in having a short +erect mane and no forelock; neither is there any dorsal stripe. The +ears are of moderate size; the whole body is of a whitish-gray, paler +beneath, and reddish on the head and upper parts of the limbs. If rightly +described this form would appear to be intermediate between the true +Horses and the Asses. + +The second species is the domestic Ass (_E. asinus_), and the wild Asses +of Africa (_E. asinus_, var. _africanus_ and var. _somalicus_[263]). The +domestic Ass, which is now nearly as widely diffused and useful to man as +the Horse, was known in Egypt long before the latter, and is doubtless +of African origin. The ears are long, the mane erect, the tail without +long hairs at the base, and there are no callosities on the hind limbs. +There is a dark dorsal stripe, and another across the shoulders; while +the limbs are frequently banded. Of the wild forms the Nubian race (var. +_africanus_) has distinct dorsal and shoulder stripes, but the rings on +the limbs are often very indistinct; while in the Somali race the dorsal +stripe is indistinct, and the shoulder stripe wanting, but the rings on +the limbs are very boldly marked. Teeth and bones from a Pleistocene +cavern deposit in Madras have been referred to _E. asinus_. + +The Asiatic wild Asses, which roam in small herds in the open plains +of Syria, of many parts of Persia, of the north-west of India, and +the highlands of Tartary and Tibet, from the shores of the Caspian +to the frontiers of China, differ from the last in being of a more +rufous or isabelline colour, instead of pure gray, in wanting the dark +streak across the shoulder, and having smaller ears. They have all a +dark-coloured median dorsal stripe. Though it is considered probable by +many zoologists that they form but a single species[264] (_E. hemionus_), +they present such marked variations in size and form that they have +commonly been divided into three—the Syrian Wild Ass (_E. hemippus_), the +Onager (_E. onager_) from Persia, Baluchistan, the Punjab, Sind, and the +desert of Kach, and the Kiang or Dzeggetai (_E. hemionus_) of the high +table-lands of Tibet, where it is usually met with at an elevation of +15,000 feet and upwards above the sea-level. The last is considerably +larger than either of the others, and differs from them in external +appearance, having more the aspect of the horse. They are all remarkably +swift, having been known to outstrip the fleetest Horse in speed. + +[Illustration: FIG. 160.—The Quagga (_Equus quagga_).] + +Lastly, there are four striped species, all inhabitants of Africa. These +constitute the genus _Hippotigris_ of Hamilton-Smith, but they are +not separable except by their coloration from the true Asses, and one +of them, the Quagga (_E. quagga_), may be considered as intermediate. +This animal was formerly met with in vast herds on the great plains of +South Africa, between the Cape Colony and the Vaal River, but now, in +common with most of the larger wild animals of that region, is becoming +extremely scarce, owing to the encroachments of European civilisation, +if, indeed, it is not already extinct. In length of ears and character of +tail it more resembles the Horse than it does the Ass, although it agrees +with the latter in wanting the callosity on the inner side of the hind +leg, just below the hock, characteristic of the Horse. The colour of the +head, neck, and upper parts of the body is reddish-brown, irregularly +banded and marked with dark brown stripes, stronger on the head and neck +and gradually becoming fainter until lost behind the shoulder. There +is a broad dark median dorsal stripe. The under surface of the body, +the legs, and tail are nearly white, without stripes. The crest is very +high, surmounted by a standing mane, banded alternately brown and white. +Though never really domesticated, Quaggas have occasionally been trained +to harness. The accompanying figure is reduced from a painting made from +one of a pair which were driven in Hyde Park in the early part of the +present century. The name is an imitation of the shrill barking neigh of +the animal—“ouag-ga, ouag-ga,” the last syllable very much prolonged. It +must be remembered, however, in reading books of African travel that the +same word is very commonly applied by hunters to Burchell’s Zebra. + +Of the Zebras proper, the one which was first known to Europeans, and +was formerly considered the most common, is the True Zebra (_E. zebra_), +sometimes called the Mountain Zebra. It inhabits the mountainous regions +of the Cape Colony; but now, owing to the advances of civilised man into +its somewhat restricted range, it has become very scarce, and is even, +like the Quagga, threatened with extermination at no distant date. The +second species, Burchell’s Zebra (_E. burchelli_), still roams in large +herds over the plains to the north of the Orange River, but in yearly +diminishing numbers. Both species are subject to considerable individual +variations in marking, but the following are the principal characters by +which they can be distinguished. + +[Illustration: FIG. 161.—True or Mountain Zebra (_Equus zebra_).] + +_E. zebra_ (Fig. 161) is the smaller of the two (about 4 feet high at +the shoulders), and has longer ears, a tail more scantily clothed with +hair, and a shorter mane. The general ground colour is white, and the +stripes are black; the lower part of the face is bright brown. With the +exception of the abdomen and the inside of the thighs, the whole of the +surface is covered with stripes, the legs having narrow transverse +bars reaching quite to the hoofs, and the base of the tail being also +barred. The outsides of the ears have a white tip and a broad black mark +occupying the greater part of the surface, but are white at the base. +Perhaps the most constant and obvious distinction between this species +and the next is the arrangement of the stripes on the hinder part of the +back, where there are a number of short transverse bands passing from the +median longitudinal dorsal stripe towards, and sometimes joining with, +the uppermost of the broad stripes which run obliquely across the haunch +from the flanks towards the root of the tail. There is often a median +longitudinal stripe under the chest. + +[Illustration: FIG. 162.—Burchell’s Zebra (_Equus burchelli_).] + +_E. burchelli_ (Fig. 162) is a rather larger and more robust animal, with +smaller ears, a longer mane, and fuller tail. The general ground colour +of the body is pale yellowish-brown, the limbs nearly white, the stripes +dark brown or black. In the typical form they do not extend on to the +limbs or the tail; but there is a great variation in this respect, even +in animals of the same herd, some being striped quite down to the hoofs +(this form has been named _E. chapmani_). There is a strongly marked +median longitudinal ventral black stripe, to which the lower ends of the +transverse side stripes are usually united, but the dorsal stripe (also +strongly marked) is completely isolated in its posterior half, and the +uppermost of the broad haunch stripes runs nearly parallel to it. A much +larger proportion of the ears is white than in the other species. In +the middle of the wide intervals between the broad black stripes of the +flanks and haunches fainter stripes are generally seen. + +_E. grevyi._—Under this name a Zebra has been described which was sent in +1882 to Paris from the Galla country, lying to the south of Abyssinia, +the most northern locality in which Zebras have previously been met +with. In many of its characters it resembles _E. zebra_, but the stripes +are much finer and more numerous than in the typical examples of that +species, and it has a strong, black, and isolated dorsal stripe. Even +allowing for the great variations that are met with in the markings of +animals of this group, the aberrant characters of this individual are +quite sufficient to separate it specifically from the true Zebra of South +Africa. Other similar specimens have been recently brought from the +Somali country. + +The flesh of the Zebras is relished by the natives as food, and their +hides are very valuable for leather. Although the many attempts that +have been made to break in and train these animals for riding or driving +have sometimes been rewarded with partial success, they have never been +domesticated in the true sense of the word. + +There are thus at least seven modifications of the Horse type at +present existing, sufficiently distinct to be reckoned as species by +all zoologists, and easily recognised by their external characters. +They are, however, all so closely allied that each will, at least in a +state of domestication or captivity, breed with perfect freedom with +any of the others. Cases of cross breeds are recorded between the Horse +and the Quagga, the Horse and Burchell’s Zebra, the Horse and the +Hemionus or Asiatic wild Ass, the common Ass and the Zebra, the common +Ass and Burchell’s Zebra, the common Ass and the Hemionus, the Hemionus +and the Zebra, and the Hemionus and Burchell’s Zebra. The two species +which are perhaps the farthest removed in general structure, the Horse +and the Ass, produce, as is well known, hybrids or Mules, which in +some qualities useful to man excel both their progenitors, and in some +countries, and for certain kinds of work, are in greater requisition +than either. Although occasional instances have been recorded of female +Mules breeding with the males of one or other of the pure species, it is +doubtful if any case has occurred of their breeding _inter se_, although +the opportunities of doing so must have been great, as Mules have been +reared in immense numbers for at least several thousands of years. We may +therefore consider it settled that the different species of the group are +now in that degree of physiological differentiation which enables them +to produce offspring with each other, but does not permit of the progeny +continuing the race, at all events unless reinforced by the aid of one of +the pure forms. + +The several members of the group show mental differences quite as +striking as those exhibited by their external form, and more than +perhaps might be expected from the similarity of their cerebral +organisation. The patience of the Ass, the high spirit of the Horse, the +obstinacy of the Mule, have long been proverbial. It is very remarkable +that, out of so many species, two only should have shown any aptitude for +domestication, and that these two should have been from time immemorial +the universal and most useful companions and servants of man, while all +the others remain in their native freedom to this day. It is, however, +still a question whether this really arises from a different mental +constitution causing a natural capacity for entering into relations +with man, or whether it may not be owing to their having been brought +gradually into this condition by long-continued and persevering efforts +when the need of their services was keenly felt. It is quite possible +that one reason why most of the attempts to add new species to the list +of our domestic animals in modern times have ended in failure is that it +does not answer to do so in cases in which existing species supply all +the principal purposes to which the new ones might be put. It can hardly +be expected that Zebras and Quaggas fresh from their native mountains +and plains can be brought into competition as beasts of burden and +draught with Horses and Asses, whose naturally useful qualities have been +augmented by the training of thousands of generations of progenitors. + +Not unfrequently instances occur of domestic Horses being produced with +a small additional toe with complete hoof, usually on the inside of the +principal toe, and, though far more rarely, three or more toes may be +present. These malformations are often cited as instances of reversion to +the condition of some of the earlier forms of equine animals previously +mentioned. Such explanations, however plausible they appear at first +sight, are nevertheless very doubtful. All the feet of polydactyle horses +which we have examined bear little resemblance to those of _Hipparion_ +or _Anchitherium_, but look rather as if due to that tendency to +reduplication of parts which occurs so frequently as a teratological +condition, especially among domestic animals, and, whatever its origin, +certainly cannot in many instances, as the cases of entire limbs +superadded, or of six digits in man, be attributed to reversion. + +_Anatomy._—The anatomical structure of the Horse has been described in +great detail in several works devoted to the subject, which will be +mentioned in the bibliography, though these have generally been written +from the point of view of the veterinarian rather than of the comparative +anatomist. The limits of the present work will only admit of the most +salient points being indicated, particularly those in which the Horse +differs from the other Ungulata. Unless otherwise specified, it must be +understood that all that is stated here, although mostly derived from +observation upon the Horse, applies equally well to the other existing +members of the group. + +[Illustration: FIG. 163.—Side view of skull of Horse, with the bone +removed so as to expose the whole of the teeth. _PMx_, Premaxilla; +_Mx_, maxilla; _Na_, nasal; _Ma_, malar or jugal; _L_, lachrymal; _Fr_, +frontal; _Sq_, squamosal; _Pa_, parietal; _oc_, occipital condyle; _pp_, +paroccipital process; _i¹_, _i²_, and _i³_³, the three incisors; _c_, the +canine; _pm¹_, the situation of the rudimentary first premolar, which has +been lost in the lower, but is present in the upper jaw; _pm²_, _pm³_, +and _pm⁴_, the three fully developed premolars; _m¹_, _m²_, and _m³_, the +three true molars.] + +_Skeleton._—The skull (Fig. 163) as a whole is greatly elongated, chiefly +in consequence of the immense size of the face as compared with the +hinder or true cranial portion. The basal line of the cranium from the +lower border of the foramen magnum to the incisor border of the palate is +very nearly straight. The orbit, of nearly circular form, though small in +proportion to the size of the whole skull, is distinctly marked, being +completely surrounded by a strong ring of bone with prominent edges. +Behind it, and freely communicating with it beneath the osseous bridge +(the postorbital process of the frontal) forming the boundary between +them, is the small temporal fossa occupying the whole of the side of +the cranium proper, and in front is the great flattened expanse of the +“cheek,” formed chiefly by the maxilla, giving support to the long row of +cheek-teeth, and having a prominent ridge running forward from below the +orbit for the attachment of the masseter muscle. The lachrymal occupies +a considerable space on the flat surface of the cheek in front of the +orbit, and below it the jugal or malar does the same. The latter sends +a horizontal or slightly ascending process backwards below the orbit to +join the under surface of the zygomatic process of the squamosal, which +is remarkably large, and, instead of ending as usual behind the orbit, +runs forwards to join the greatly developed postorbital process of the +frontal, and even forms part of the posterior and inferior boundary of +the orbit, an arrangement not met with in other mammals. The closure +of the orbit behind distinguishes the skull of the Horse from that of +the Rhinoceros and Tapir, and also from all of the Perissodactyles of +the Eocene period. In front of the cerebral cavity, the great tubular +nasal cavities are provided with well-developed turbinal bones, and are +roofed over by very large nasals, broad behind, and ending in front in +a narrow decurved point. The opening of the anterior nares is prolonged +backwards on each side of the face between the nasals and the elongated +slender premaxillæ. The latter expand in front, and are curved downwards +to form the semicircular alveolar border supporting the large incisor +teeth. The palate is narrow in the interval between the incisor and +cheek-teeth, in which are situated the large anterior palatine foramina. +Between the cheek-teeth it is broader, and it ends posteriorly in a +rounded excavated border opposite the hinder edge of the penultimate +molar. It is mainly formed by the maxillæ, as the palatines are very +narrow. The pterygoids are delicate slender slips of bone attached to +the hinder border of the palatines, and supported externally by, and +generally ankylosed to, the rough pterygoid plates of the alisphenoid, +with no pterygoid fossa between. They slope very obliquely forwards, +and end in curved, compressed, hamular processes. There is a distinct +alisphenoid canal for the passage of the internal maxillary or main +branch of the external carotid artery. The base of the cranium is long +and narrow; the alisphenoid is very obliquely perforated by the foramen +rotundum, but the foramen ovale is confluent with the large foramen +lacerum medium behind. The glenoid surface for the articulation of the +mandible is greatly extended transversely, concave from side to side, +convex from before backwards in front, and hollow behind, and is bounded +posteriorly at its inner part by a prominent post-glenoid process. The +squamosal enters considerably into the formation of the temporal fossa, +and, besides sending the zygomatic process forwards, it sends down +behind the meatus auditorius a post-tympanic process which aids to hold +in place the otherwise loose tympano-periotic bone. Behind this the +exoccipital gives off a very long paroccipital process. The periotic +and tympanic are ankylosed together, but not with the squamosal. The +former has a wide but shallow floccular fossa on its inner side, and +sends backwards a considerable “pars mastoidea,” which appears on the +outer surface of the skull between the post-tympanic process of the +squamosal and the exoccipital. The tympanic forms a tubular meatus +auditorius externus directed outwards and slightly backwards. It is not +dilated into a distinct bulla, but ends in front in a pointed styliform +process; and completely embraces the truncated cylindrical tympanohyal, +which is of great size, in correspondence with the large development of +the whole anterior arch of the hyoid. This consists mainly of a long +and compressed stylohyal, expanded at the upper end, where it sends +off a triangular posterior process. The basihyal is remarkable for the +long, median, pointed, compressed “glossohyal” process, which it sends +forward from its anterior border into the base of the tongue. A similar +but less developed process is found in the Rhinoceros. The mandible is +largely developed, especially the region of the angle, which is expanded +and flattened, giving great surface for the attachment of the masseter +muscle. The condyle is greatly elevated above the alveolar border; its +articular surface is very wide transversely, and narrow and convex +from before backwards. The coronoid process is slender, straight, and +inclined backwards. The horizontal ramus, long, straight, and compressed, +gradually narrows towards the symphysis, where it expands laterally to +form with the ankylosed opposite ramus the wide, semicircular, shallow +alveolar border for the incisor teeth. + +The vertebral column consists of seven cervical, eighteen dorsal, six +lumbar, five sacral, and fifteen to eighteen caudal vertebræ. There +may be nineteen rib-bearing vertebræ, in which case five only will be +reckoned as belonging to the lumbar series. The odontoid process of the +atlas is wide, flat, and hollowed above, as in the Ruminants. The bodies +of the cervical vertebræ are elongated, strongly keeled, and markedly +opisthocœlous, or concave behind and convex in front. Their neural laminæ +are very broad, the spines almost obsolete, except in the seventh, and +the transverse processes not largely developed. In the trunk vertebræ the +opisthocœlous character of the centrum gradually diminishes. The spinous +processes of the anterior thoracic region are high and compressed. To +these is attached the powerful elastic ligament, _ligamentum nuchæ_, or +“paxwax,” which passing forwards in the middle line of the neck above the +neural arches of the cervical vertebræ, to which it is also connected, +is attached to the occiput and supports the weight of the head. The +transverse processes of the lumbar vertebræ are long, flattened, and +project horizontally outwards or slightly forwards from the arch. The +metapophyses are moderately developed, and there are no anapophyses. +The caudal vertebræ, except those quite at the base, are slender and +cylindrical, without processes and without chevron-bones beneath. The +ribs are eighteen or nineteen in number on each side, flattened, and +united to the sternum by short, stout, tolerably well ossified sternal +ribs. The sternum consists of six pieces; the anterior or presternum +being extremely compressed, and projecting forwards like the prow of a +boat. The segments which follow gradually widen, and the hinder part of +the sternum is broad and flat. + +As in all other Ungulates, there are no clavicles. The scapula is +long and slender; the suprascapular border is rounded, and slowly and +imperfectly ossified. The spine is very slightly developed; rather above +the middle its edge is thickened and somewhat turned backwards, but it +gradually subsides at the lower extremity without forming any acromial +process. The coracoid process is a prominent rounded nodule. The humerus +is stout and rather short, and has a double bicipital groove. The ulna +is quite rudimentary, being only represented by little more than the +olecranon. The shaft gradually tapers below, and is firmly ankylosed to +the radius. The latter bone is of nearly equal width throughout. The +three bones of the first row of the carpus (the scaphoid, lunar, and +cuneiform) are subequal in size. The second row consists of a very broad +and flat magnum, supporting the great third metacarpal, having to its +radial side the trapezoid, and to its ulnar side the unciform, which +are both small, and articulate distally with the rudimentary second and +fourth metacarpals. The pisiform is large and prominent, flattened, +and curved; articulating partly with the cuneiform and partly with the +lower end of the radius. The large metacarpal is called in veterinary +anatomy “cannon-bone”; the small lateral metacarpals, which gradually +taper towards their lower extremities, and lie in close contact with +the large one, are called “splint-bones.” The single digit consists of +a moderate-sized proximal (_os suffraginis_, or large pastern), a very +short middle (_os coronæ_, or small pastern), and a wide, semilunar, +ungual phalanx (_os pedis_, or coffin-bone). There is a pair of large +nodular sesamoids behind the metacarpo-phalangeal articulation, and a +single large transversely extended sesamoid behind the joint between the +second and third phalanx, called the “navicular bone.”[265] + +The carpal joint, corresponding to the wrist of man, is commonly called +the “knee” of the Horse, the joint between the metacarpal and the first +phalanx the “fetlock,” that between the first and second phalanges +the “pastern,” and that between the second and third phalanges the +“coffin-joint.” + +In the hind limb the femur is marked, as in other Perissodactyles, by the +presence of a “third trochanter,” a flattened process, curving forwards, +arising from the outer side of the bone, about one-third of the distance +from the upper end. The fibula is reduced to a mere styliform rudiment +of the upper end; its lower part being absent or completely fused with +the tibia. The calcaneum has a long and compressed calcaneal process. The +astragalus has a large flat articular surface in front for the navicular, +and a very small one for the cuboid. The navicular and the external +cuneiform bones are very broad and flat. The cuboid is small, and the +internal and middle cuneiform bones are small and united together. The +metapodials and phalanges resemble very closely those of the fore limb, +but the principal metatarsal is more laterally compressed at its upper +end than is the corresponding metacarpal. The joint between the femur and +tibia, corresponding to the knee of man, is called the “stifle joint”; +while that between the tibia and tarsus, corresponding to the ankle of +man, is termed the “hock.” The bones and joints of the foot have the +same names as in the fore limb. The Horse is eminently “digitigrade,” +standing on the extremity of the single digit of each foot, which is kept +habitually in a position approaching to vertical. + +The muscles[266] of the limbs are modified from those of the ordinary +mammalian type in accordance with the reduced condition of the bones +and the simple requirements of flexion and extension of the joints, no +such actions as pronation and supination, or opposition of digits, being +possible or needed. The muscles, therefore, which perform these functions +in other mammals are absent or rudimentary. + +[Illustration: FIG. 164.—Section of foot of Horse. 1, Metacarpal bone; +2, first phalanx (_os suffraginis_); 3, second phalanx (_os coronæ_); +4, third or ungual phalanx (_os pedis_, or coffin-bone); 5, one of the +upper sesamoid bones; 6, lower sesamoid or “navicular” bone; 7, tendon +of anterior extensor of the phalanges; 8, tendon of superficial flexor +(_fl. perforatus_); 9, tendon of deep flexor (_fl. perforans_); 10, +suspensory ligament of fetlock; 11, inferior or short sesamoid ligament; +12, derma or skin of the foot, covered with hair, and continued into 13, +the coronary cushion, 14, the podophyllous or laminar membrane, and 15, +the keratogenous membrane of the sole; 16, plantar cushion; 17, hoof; 18, +fatty cushion of fetlock.] + +Below the carpal and tarsal joints the fore and hind limbs correspond +almost exactly in structure as well as function. On the anterior or +extensor surface of the limb a powerful tendon (7 in Fig. 164), that of +the anterior extensor of the phalanges (corresponding to the _extensor +communis digitorum_ of the arm and _extensor longus digitorum_ of the +foot of man) passes down over the metacarpal bone and phalanges, to be +inserted mainly into the upper edge of the anterior surface of the last +phalanx or pedal bone. There is also a much smaller second extensor +on the outer side of this in each limb, the lateral extensor of the +phalanges. In the fore leg the tendon of this muscle (which corresponds +with the _extensor minimi digiti_ of man) receives a slip from that of +the principal extensor, and is inserted into the first phalanx. In the +hind leg (where it is the homologue apparently of the _peroneus brevis_ +of man) the tendon becomes blended with that of the large extensor. + +A very strong ligamentous band behind the metapodium, arising from near +the upper extremity of its posterior surface, divides into two at its +lower end, and each division, being first connected with one of the +paired upper sesamoid bones, passes by the side of the first phalanx to +join the extensor tendon of the phalanges. This is called in veterinary +anatomy the “suspensory ligament of the sesamoids,” or of the “fetlock” +(10 in Fig. 164); but its attachments and relations, as well as the +occasional presence of muscular fibres in its substance, show that it +is the homologue of the short flexor muscle of other mammals, curiously +modified both in structure and function to suit the requirements of the +Horse’s foot. Behind or superficial to this are placed the two strong +tendons of the long flexor muscles, the most superficial, or _flexor +perforatus_ (8), dividing to allow the other to pass through, and then +inserted into the middle phalanx. The _flexor perforans_ (9) is as +usual inserted into the terminal phalanx. In the fore leg these muscles +correspond with those similarly named in man. In the hind leg, the +perforated tendon is a continuation of that of the plantaris, passing +pulley-wise over the tuberosity of the calcaneum. The perforating tendon +is derived from the muscle corresponding with the long flexor of man, and +the smaller tendon of the oblique flexor (_tibialis posticus_ of man) is +united with it. + +The hoof of the Horse corresponds to the nail or claw of other mammals, +but is so constructed as to form a complete and very solid case to the +expanded termination of the toe, giving a firm basis of support formed of +a nonsensitive substance, which is continually renewed by the addition of +material from within as its surface wears away by friction against the +ground. The terminal phalanx of the toe is greatly enlarged and modified +in form to support this hoof, and the size of the internal framework of +the foot is further increased by a pair of lateral fibro-cartilaginous +masses attached on each side to the hinder edges of the bone, and by a +fibro-cellular and adipose plantar cushion in the median part. These +structures are all enclosed in the keratogenous membrane or “subcorneous +integument,” a continuation of the ordinary derma of the limb, but +extremely vascular, and having its superficial extent greatly increased +by being developed into papillæ or laminæ. From this the horny material +which constitutes the hoof is exuded. A thickened ring encircling the +upper part, called coronary cushion (13), and the sole (15), are covered +with numerous thickly set papillæ or villi, and take the greatest share +in the formation of the hoof; the intermediate part constituting the +front and side of the foot (14), corresponding with the wall of the +hoof, is covered with parallel, fine longitudinal laminæ, fitting into +corresponding depressions in the inner side of the horny hoof. + +The horny hoof is divided into a wall or crust consisting of the front +and sides, the flattened or concave sole, and the “frog,” a triangular +median prominence, notched posteriorly, with the apex turned forwards, +situated in the hinder part of the sole. It is formed of pavement +epithelial cells, mainly grouped in a concentric manner around the +vascular papillæ of the keratogenous membrane, so that a section near the +base of the hoof, cut transversely to the long axis of these papillæ, +shows a number of small circular or oval orifices, with cells arranged +concentrically round them. The nearer the surface of the hoof, or farther +removed from the seat of growth, the more indistinct the structure +becomes. + +Small round or oval plates of horny epidermis called “chestnuts,” growing +like the hoof from enlarged papillæ of the skin, are found on the +inner face of the fore limb, above the carpal joint, in all species of +_Equidæ_, and in the Horse (_E. caballus_) alone similar formations occur +near the upper extremity of the inner face of the metatarsus. Their use +is unknown. + +Behind the joint between the metapodium and the first phalanx is a +prominence formed by the fatty cushion of the fetlock (18 in Fig. 164). +On the middle of this is a small bare patch covered with thickened +epidermis, the _ergot_ or spur, generally concealed beneath the long hair +which grows around it. This is the functionless vestige of the large +callous pad found in this situation in the Tapir, and in fact in all +mammals in which this part reaches the ground in walking. + +[Illustration: FIG. 165.—Longitudinal and transverse section of upper +incisor of Horse. _p_, Pulp cavity; _d_, dentine or ivory; _e_, enamel; +_c_, outer layer of cement; _c′_, inner layer of cement, lining _a_, the +pit or cavity of the crown of the tooth.] + +_Dentition._—The dentition of the Horse, when all the teeth are in place, +is, as stated before, expressed by the formula _i_ ³⁄₃, _c_ ¹⁄₁, _p_ +⁴⁄₃, _m_ ³⁄₃ = 42. The incisors of each jaw are placed in close contact, +forming a semicircle. The crowns are broad, somewhat awl-shaped, and of +nearly equal size. They have all the great peculiarity, not found in +the teeth of any other living mammal, of an involution of the external +surface of the tooth (see Fig. 165) forming a deep fossa or pit, the +bottom of which becomes partially filled up with cement. As the tooth +wears, the surface, besides the external enamel layer as in an ordinary +simple tooth, shows in addition a second inner ring of the same hard +substance surrounding the pit, thus of course adding greatly to the +efficiency of the tooth as an organ for biting tough, fibrous substances. +This pit, generally filled in the living animal with particles of food, +is conspicuous from its dark colour, and constitutes the “mark” by which +the age of the horse is judged, as in consequence of its extending only +to a certain depth, it becomes obliterated as the crown wears away, +when the tooth assumes the character of an ordinary incisor, consisting +only of a core of dentine surrounded by the external enamel layer. It +is not quite so deep in the lower as in the upper teeth. The canines +are either quite rudimentary or entirely absent in the female. In the +male they are compressed, pointed, and smaller than the incisors, from +which they are separated by a slight interval. The teeth of the cheek +series are all in contact with each other, but separated from the canines +by a considerable toothless space. The anterior premolars are quite +rudimentary, often, especially in the lower jaw, not developed at all, +and generally fall by the time the animal attains maturity, so that there +are but six functional grinding teeth—three that have predecessors in +the milk-dentition, and hence are considered as premolars, and three +true molars, but otherwise, except the first and last of the series, +not distinguishable in form or structure. These teeth in both upper and +lower jaws are extremely long-crowned or hypsodont (Fig. 158), successive +portions being pushed out as the surface wears away;—a process which +continues until the animal becomes advanced in age. The enamelled surface +is infolded in a complex manner (a modification of that found in other +Perissodactyles, see Figs. 155, 167), the folds extending quite to the +base of the crown, and the interstices being filled and the surface +covered with a considerable mass of cement, which binds together and +strengthens the whole tooth. As the teeth wear, the folded enamel, +being harder than the other constituents—the dentine and cement—forms +projecting ridges on the surface arranged in a definite pattern, which +give it great efficiency as a grinding instrument (see Fig. 157, _b_ and +_c_). The free surfaces of the upper teeth are quadrate, except the first +and last, which are nearly triangular. The lower teeth are much narrower +than the upper. + +The milk dentition consists of _i_ ³⁄₃, _c_ ⁰⁄₀, _m_ ³⁄₃ = 24,—the +canines and first or rudimentary premolars having apparently no +predecessors. In form and structure they much resemble the permanent +teeth, having the same characteristic enamel-foldings. Their eruption +commences a few days after birth, and is complete before the end of the +first year, the upper teeth usually appearing somewhat earlier than those +of the lower jaw. The first teeth to appear are the first and second +milk-molars (about five days), then the central incisor (from seven to +ten days); this is followed by the second incisor (at one month), then +by the third molar, and finally by the third incisor. Of the permanent +teeth the first true molar appears a little after the end of the first +year, followed by the second molar before the end of the second year. At +about two and a half years the first premolar replaces its predecessor. +Between two and a half and three years the first incisor appears. At +three years the second and third premolars and the third true molar have +appeared; at from three and a half to four years the second incisor; at +four to four and a half years the canine; and, finally, at five years the +third incisor, completing the permanent dentition. Up to this period the +age of the horse is clearly shown by the state of the dentition, and for +some time longer indications can be obtained from the wear of the incisor +teeth, though this depends to a certain extent upon the hardness of the +food or other accidental circumstances. As a general rule, the depression +caused by the infolding of the surface of the incisor (the “mark”), is +obliterated in the first or central incisor at six years, in the second +at seven years, and in the third at eight years. In the upper teeth, as +the depressions are deeper, this obliteration does not take place until +about two years later. After this period no certain indications can be +obtained of the age of the horse from the teeth. + +_Digestive Organs._—The lips are flexible and prehensile. The membrane +that lines them and the cheeks is quite smooth. The palate is long and +narrow; its mucous surface has seventeen pairs of not very sharply +defined oblique ridges, extending as far back as the last molar tooth, +beyond which the velum palati extends for about 3 inches, having a soft +corrugated surface, and ending posteriorly in an arched border without +uvula. This embraces the base of the epiglottis, and shuts off all +communication between the cavity of the mouth and the nasal passages, +respiration being, under ordinary circumstances, carried on exclusively +through the nostrils. Between the mucous membrane and the bone of the +hard palate is a dense vascular and nervous plexus. The membrane lining +the fauces is soft and corrugated. An elongated raised glandular mass, +3 inches long and 1 inch from above downwards, extending backwards from +the root of the tongue along the side of the fauces, with openings on the +surface leading into crypts with glandular walls, represents the tonsil. +The tongue, corresponding to the general form of the mouth, is long and +narrow. It consists of a compressed intermolar portion with a flat upper +surface, broad behind and becoming narrower in front; and of a depressed +anterior part rather shorter than the former, which is narrow behind but +widens towards the evenly rounded apex. The dorsal surface generally is +very soft and smooth. There are two large circumvallate papillæ near the +base, rather irregular in form, about a quarter of an inch in diameter +and half an inch apart. The conical papillæ are very small and close set, +though longer and more filamentous on the intermolar portion. There are +no fungiform papillæ on the dorsum, but a few not very conspicuous ones +scattered along the sides of the organ. + +Of the salivary glands the parotid is by far the largest; elongated in +the vertical direction, and narrower in the middle than at either upper +or lower extremity. Its upper extremity embraces the lower surface of +the cartilaginous ear-conch; its lower end reaches the level of the +inferior margin of the mandible, along the posterior margin of which it +is placed. Its duct leaves the inferior anterior angle, at first descends +a little, and runs forward under cover of the rounded inferior border of +the mandibular ramus, then curves up along the anterior margin of the +masseter muscle, becoming superficial, pierces the buccinator, and enters +the mouth by a simple aperture opposite the middle of the crown of the +third premolar tooth. It is not quite so thick as a goose-quill when +distended, and nearly a foot in length. + +The submaxillary gland is of very similar texture to the last, but much +smaller; it is placed deeper, and lies with its main axis horizontal. +It is elongated and slender, and flattened from within outwards. Its +posterior end rests against the anterior surface of the transverse +process of the atlas, from which it extends forwards and downwards, +slightly curved, to beneath the ramus of the jaw. The duct which runs +along its upper and internal border passes forwards in the usual course, +lying in the inner side of the sublingual gland, to open on the outer +surface of a distinct papilla, situated on the floor of the mouth, half +an inch from the middle line, and midway between the lower incisor teeth +and the attachment of the frænum linguæ. The sublingual is represented by +a mass of glands lying just beneath the mucous membrane of the floor of +the mouth on the side of the tongue, causing a distinct ridge, extending +from the frænum backwards, and the numerous ducts opening separately +along the summit of the ridge. The buccal glands are arranged in two rows +parallel with the molar teeth. The upper ones are the largest, and are +continuous anteriorly with the labial glands, the ducts of which open on +the mucous membrane of the upper lip. + +The stomach of the Horse is simple in its external form, with a largely +developed right _cul de sac_, and is a good deal curved on itself, +so that the cardiac and pyloric orifices are brought near together. +The antrum pyloricum is small and not very distinctly marked off. The +interior is divided by the character of the lining membrane into two very +distinct portions, right and left. Over the latter the dense white smooth +epithelial lining of the œsophagus is continued, terminating abruptly +by a raised crenellated border. Over the right part (rather the larger +portion) the mucous membrane has a grayish-red colour and a velvety +appearance, and contains very numerous peptic glands, which are wanting +in the cardiac portion. The œsophageal orifice is very small, and is +guarded by a strong crescentic or rather horse-shoe-like band of muscular +fibres, which is supposed to be the cause of the difficulty of vomiting +in the Horse. The small intestine is of great length (80 to 90 feet), +its mucous membrane being covered with numerous fine villi. The cæcum is +of conical form, about 2 feet long and nearly a foot in diameter; its +walls are sacculated, especially near the base, having four longitudinal +fibrous bands; and its capacity is about twice that of the stomach. It +lies with its base near the lower part of the abdomen, and its apex +directed towards the thorax. The colon is about one-third the length +of the small intestine, and very capacious in the greater part of its +course. As usual, it may be divided into an ascending, transverse, and +descending portion; but the middle or transverse portion is folded into a +great loop, which descends as low as the pubis; so that the colon forms +altogether four folds, generally parallel to the long axis of the body. +The descending colon is much narrower than the rest, and not sacculated, +and being considerably longer than the distance it has to traverse, is +thrown into numerous folds. + +The liver (Fig. 166) is tolerably symmetrical in its general arrangement, +being divided nearly equally into segments by a well-marked umbilical +fissure. Each segment is again divided by lateral fissures, which do +not extend quite to the posterior border of the organ; of the central +lobes thus cut off, the right is rather the larger, and has two fissures +in its free border subdividing it into lobules. The extent of these +varies, however, in different individuals, being not usually so marked +as in the figure, which is from a fœtal specimen. The two lateral lobes +are subtriangular in form. The Spigelian lobe is represented by a +flat surface between the portal fissure and the posterior border, not +distinctly marked off from the left lateral by a fissure of the ductus +venosus, as this vessel is buried deep in the hepatic substance, but +the caudate lobe is distinct and tongue-shaped, its free apex reaching +nearly to the border of the right lateral lobe. In most works on the +anatomy of the Horse this has been confounded with the Spigelian lobe of +man. There is no gall-bladder (as in all other Perissodactyles), and the +biliary duct enters the duodenum about 6 inches from the pylorus. The +pancreas has two lobes or branches—a long one passing to the left and +reaching the spleen, and a shorter right lobe. The principal duct enters +the duodenum with the bile-duct, and there is often a second small duct +which opens separately near to this. + +[Illustration: FIG. 166.—Under surface of the liver of the Horse. _u_, +Umbilical fissure; _ll_, left lateral lobe; _lc_, left central lobe; +_rc_, right central lobe; _rl_, right lateral lobe; _s_, Spigelian lobe; +_c_, caudate lobe.] + +_Circulatory and Respiratory Organs._—The heart has the form of a rather +elongated and pointed cone. There is one anterior vena cava, formed by +the union of the two jugular and two axillary veins. The aorta gives off +a large branch (the anterior aorta) very near its origin, from which +arise—first, the left axillary, and afterwards the right axillary and the +two carotid arteries. + +Under ordinary circumstances the Horse breathes entirely by the nasal +passages, the communication between the larynx and the mouth being +closed by the velum palati. The nostrils are placed laterally, near +the termination of the muzzle, and are large and very dilatable, being +bordered by cartilages upon which several muscles act. Immediately within +the opening of the nostril, the respiratory canal sends off on its upper +and outer side a diverticulum or blind pouch (called “false nostril”) of +a conical form, and curved, 2 to 3 inches in depth, lying in the notch +formed between the nasal and premaxillary bones. It is lined by mucous +membrane continuous with that of the nasal passage, but its use is not +apparent. It is longer in the Ass than in the Horse. A similar structure +is found in the Rhinoceros, and in a much more developed condition in +the Tapir. Here may be mentioned the guttural pouches, large air sacs, +diverticula from the Eustachian tubes, and lying behind the upper part +of the pharynx. These are likewise found in other Perissodactyles, +but their use is also still not clearly understood. The larynx has the +lateral sacculi well developed, though entirely concealed within the alæ +of the thyroid cartilage. The trachea divides into two bronchi, one for +each lung. + +_Nervous System._—The brain differs little, except in details of +arrangement of convolutions, from that of other Ungulates. The cerebral +hemispheres are rather elongated and subcylindrical, the olfactory +lobes are large and project freely in front of the hemispheres, and the +greater part of the cerebellum is uncovered. The eye is provided with a +nictitating membrane or third eyelid, at the base of which the ducts of +the Harderian gland open. + +_Reproductive System._—The testes are situated in a distinct sessile or +slightly pedunculated scrotum, into which they descend from the sixth +to the tenth month after birth. The accessory generative glands are +the two vesiculæ seminales, with the median third vesicle, or _uterus +masculinus_, lying between them, the single bilobed prostate, and a pair +of globular Cowper’s glands. The penis is large, cylindrical, with a +truncated, expanded, flattened termination. When in a state of repose it +is retracted by a muscle arising from the sacrum, within the prepuce, a +cutaneous fold attached below the symphysis pubis. + +The uterus is bicornuate. The vagina is often partially divided by a +membraneous septum or hymen. The mammæ (as in other members of the +suborder), are two, inguinally placed. The surface of the chorion is +covered evenly with minute villi, constituting a diffuse non-deciduate +placenta. The period of gestation is eleven months. + + _Bibliography._—M. S. Arloing, “Organisation du pied chez le + cheval,” _Ann. Sci. Nat._ 1867, viii. pp. 55-81; H. Burmeister, + _Los caballos fosiles de la Pampa Argentina_, Buenos Ayres, + 1875; Chanveau and Arloing, _Traité d’anatomie comparée des + animaux domestiques_, Paris, 1871, and English edition by G. + Fleming, 1873; E. Cuyer and E. Alix, _Le Cheval_, 1886; A. + Ecker, “Das Europäische Wildpferd und dessen Beziehungen zum + domesticirten Pferd,” _Globus_, Bd. xxxiv. Brunswick, 1878; + Forsyth-Major, “Beiträge zur Geschichte der fossilen Pferde + besonders Italiens,” _Abh. Schw. Pal. Ges._ iv. pp. 1-16, pt. + iv.; George, “Études zool. sur les Hémiones et quelques autres + espèces chevalines,” _Ann. Sci. Nat._ 1869, xii. p. 5; E. F. + Gurlt, _Anatomische Abbildungen der Haussäugethiere_, 1824, + and _Hand. der vergleich. Anat. der Haussäugethiere_, 2 vols. + 1822; Huet, “Croisement des diverses espèces du genre cheval,” + _Nouv. Archives du Muséum_, 2d sér. tom. ii. p. 46, 1879; + Leisering, _Atlas der Anatomie des Pferdes_, Leipsic, 1861; + J. M’Fadyean, _The Anatomy of the Horse_, 1884; O. C. Marsh, + “Notice of New Equine Mammals from the Tertiary Formation,” + _Am. Journ. of Science and Arts_, vol. vii. March 1874; Id. + “Fossil Horses in America,” _Amer. Naturalist_, vol. viii. + May 1874; Id. “Polydactyle Horses,” _Am. Journ. of Science + and Arts_, vol. xvii. June 1879; Franz Müller, _Lehrbuch der + Anatomie des Pferdes_, Vienna, 1853; R. Owen, “Equine Remains + in Cavern of Bruniquel,” _Phil. Trans._ vol. clix. (1870), p. + 535; W. Percivall, _The Anatomy of the Horse_, 1832; G. Stubbs, + _Anatomy of the Horse_, 1766. F. H. Huth’s _Bibliographical + Record of Hippology_ (1887) contains a list of nearly four + thousand works on Horses and Equitation, published in the + various languages of the civilised world. + + +_Family_ RHINOCEROTIDÆ. + +Although the existing members of this family are readily distinguished +from the other living representatives of the suborder by the simple +crescentoid form assumed by the ridges of the lower cheek-teeth, yet +it is exceedingly difficult to give a definition by which they can be +distinguished from the _Lophiodontidæ_, from some members of which they +are, indeed, probably derived. The outer columns of the upper molars +(Fig. 167) are, however, so excessively flattened as to produce a +continuous thick and nearly straight outer wall, which is often produced +in advance of the anterior transverse ridge; both transverse ridges +being but little curved, and intimately connected with the outer wall. +The upper premolars are in most cases nearly or quite as complex as the +molars, and the ridges of the lower cheek-teeth are crescentoid. The +last lower molar has no third lobe. The height of the crowns of the +cheek-teeth is variable. The skull is large, with the orbit confluent +with the temporal fossa. There are either three or four digits in the +manus, and three in the pes. One or more dermal horns are attached to +the fronto-nasal region of the skull of existing forms, but these were +wanting in some of the fossil species. + +[Illustration: FIG. 167.—A partially worn second right upper molar of +_Rhinoceros antiquitatis_. Letters as in Fig. 155 (p. 375), except _k_, +which indicates a prolongation of the median valley. (After Owen.)] + +_Rhinoceros._[267]—Incisors variable, reduced in number, often quite +rudimentary, and early deciduous. Upper canines absent. Molar series, +consisting of the full number of four premolars and three molars above +and below, all in contact and closely resembling each other, except +the first, which is much smaller than the rest and often deciduous; +and the last, in which the hinder lobe is partly aborted, so that the +contour of the crown is triangular. Head large, skull elongated, elevated +posteriorly into a transverse occipital crest. No postorbital processes. +Nasal bones large and stout, co-ossified, and standing out freely above +the premaxillæ, from which they are separated by a deep and wide fissure; +the latter small, generally not meeting in the middle line in front, +often quite rudimentary. Tympanics small, not forming a bulla. Brain +cavity very small for the size of the skull. Vertebræ: C 7, D 19-20, L 3, +S 4, C about 22. Limbs stout, and of moderate length. Three completely +developed toes, with distinct broad rounded hoofs on each foot (Fig. 151, +p. 368), some fossil forms having a fourth in the manus. Eyes small. Ears +of moderate size, oval, erect, prominent, placed near the occiput. Skin +very thick, in many species thrown into massive folds. Hairy covering +scanty. When one horn is present it is situated over the conjoined nasal +bones; when two, the hinder one is over the frontals. These horns, which +are of a more or less conical form and usually recurved, often grow to +a great length (three or even four feet), and are composed of a solid +mass of hardened epidermic cells growing from a cluster of long dermal +papillæ. The cells formed on each papilla constitute a distinct horny +fibre, like a thick hair, and the whole are cemented together by an +intermediate mass of cells which grow up from the interspaces between +the papillæ. It results from this that the horn has the appearance of a +mass of agglutinated hairs, which, in the newly growing part at the base, +readily fray out on destruction of the softer intermediate substance; but +the fibres differ from true hairs in growing from a free papilla of the +derm, and not within a follicular involution of the same. + +[Illustration: FIG. 168.—A partially worn second right upper molar of +(_A_) _Rhinoceros sondaicus_, and (_B_) _R. unicornis_. _k_, Fossette cut +off from median valley; _m_, crotchet; _n_, crista, or combining-plate; +_e_, anterior valley; _l_, anterior intermediate column. Other letters as +in Fig. 155, p. 375.] + +The large lower cutting teeth of the typical Rhinoceroses have been +very generally regarded as incisors, but comparison with fossil allied +types, in which three lower incisors and canines are present, leaves +little doubt but that they are really canines. The upper molar teeth +present some amount of specific variation; thus while one type (Fig. +168, _A_) has only a simple “crotchet” projecting from the posterior +transverse ridge into the median valley, in others (Fig. 168, _B_) +this crotchet joins a “crista,” or “combing-plate,” projecting from +the outer wall to cut off a distinct fossette from the median valley. +Occasionally, however (as in Fig. 167), the crotchet and combing-plate +do not completely join, although the fossette is distinctly indicated. +The first upper premolar may occasionally be preceded by a milk-tooth. +The Rhinoceroses differ from the Horses and agree with the Tapirs in the +direction of the cæcum. + +The living species of _Rhinoceros_ are all animals of large size, but +of little intelligence, generally timid indisposition, though ferocious +when attacked and brought to bay, using the nasal horns as weapons, by +which they strike and toss their assailant. Their sight is dull, but +their hearing and scent are remarkably acute. They feed on herbage, +shrubs, and leaves of trees, and, like so many other large animals which +inhabit hot countries, sleep the greater part of the day, being most +active in the cool of the evening or even during the night. They are fond +of bathing and wallowing in water or mud. None of the species have been +domesticated. Animals of the group have existed in both the Old and New +Worlds since the latter part of the Eocene period. In America they all +became extinct before the end of the Pliocene period. In the Old World +their distribution has become greatly restricted, and they are no longer +found in Europe and North Asia, but only in Africa and portions of the +Indian and Indo-Malayan region. + +_Existing Species._—The existing (as well as many of the extinct) species +of Rhinoceroses naturally divide into three groups, which are regarded by +some zoologists as of generic value. + +_Rhinocerotic, or Typical Group._—The adults with a single large +compressed incisor above on each side, and occasionally a small lateral +one; below, a very small incisor and a very large, procumbent, pointed +canine. Nasal bones pointed in front. A single nasal horn. Skin very +thick, and raised into strong, definitely arranged ridges or folds. + +[Illustration: FIG. 169.—Indian Rhinoceros (_Rhinoceros unicornis_). This +figure, and also figures 170, 172, are reduced from drawings by J. Wolf, +from animals living in the London Zoological Society’s Gardens.] + +There are two well-marked species of one-horned Rhinoceroses. (1) The +Indian Rhinoceros, _R. unicornis_ (Fig. 169) of Linnæus,[268] the +largest and best known, from being the most frequently exhibited alive +in England, is at present only met with in a wild state in the terai +region of Nipal and Bhutan, and in the upper valley of the Brahmaputra +or province of Assam, though it formerly had a wider range. The first +Rhinoceros seen alive in Europe since the time when these animals, in +common with nearly all the large remarkable beasts of both Africa +and Asia, were exhibited in the Roman shows, was of this species. It +was sent from India to Emmanuel, King of Portugal, in 1513; and from +a sketch of it, taken in Lisbon, Albert Dürer composed his celebrated +but rather fanciful engraving, which was reproduced in so many old +books on natural history. Both in this and the following species the +post-glenoid and post-tympanic processes of the squamosal bone of the +skull unite below so as to completely surround the external auditory +meatus. The molar teeth are hypsodont, and have a horizontal plane of +wear; those of the upper jaw (Fig. 168, _b_) being characterised by the +presence of a combing-plate joining the crotchet, and the absence of +a distinct buttress at the antero-external angle. The stomach departs +from the ordinary Perissodactyle type. The small intestine is beset +over most of its surface with long and fine villi; and the Spigelian +lobe of the liver is well developed. There is a gland behind the foot. +Teeth from the Pleistocene of the Narbada valley in India apparently +indicate the existence of the Indian Rhinoceros at that epoch. (2) The +Javan Rhinoceros (_R. sondaicus_, Fig. 170) is a smaller form, readily +distinguished by dental and internal characters, as well as by the +different arrangement of the plications of the skin (as seen in the +figures); the horn in the female appears to be very little developed, if +not altogether absent. This species has a more extensive geographical +range, being found in the Bengal Sunderbans near Calcutta, Burma, the +Malay Peninsula, Java, Sumatra, and probably Borneo. The molar teeth have +shorter crowns than in the preceding species, and wear into ridges; +those of the upper jaw (Fig. 168, _a_) having no combing-plate, and a +strongly marked buttress at the antero-external angle (not distinctly +shown in the figure). The visceral anatomy, according to Beddard,[269] +does not differ materially from that of the next species. In respect +to its dentition and anatomical characters this species is indeed more +nearly allied to the Sumatran than to the Indian Rhinoceros; and thereby +indicates that the division of the existing Rhinoceroses into separate +genera is not advisable. + +[Illustration: FIG. 170.—Javan Rhinoceros (_Rhinoceros sondaicus_).] + +_Ceratorhine Group._—The adults with a moderate-sized compressed incisor +above, and a laterally placed, pointed, procumbent canine below, which is +sometimes lost in old animals. Nasal bones narrow and pointed anteriorly. +A well-developed nasal, and a small frontal horn separated by an +interval. The skin thrown into folds, but these not so strongly marked +as in the former group. The smallest living member of the family, the +Sumatran Rhinoceros, _R. sumatrensis_, Cuvier, now represents this group. +Its geographical range is nearly the same as that of the Javan species, +though not extending into Bengal; but it has been found in Assam, +Chittagong, Burma, the Malay Peninsula, Sumatra, and Borneo. So far as +can be determined during the life of the type specimen, it appears that +the hairy form from Chittagong, described as _R. lasiotis_, is only a +variety of this species.[270] The molar teeth of the Sumatran Rhinoceros +are almost indistinguishable from those of the Javan species, and +reference has already been made to the resemblance between the visceral +anatomy of these species.[271] The form of the stomach is very similar to +that of the Horse. The liver (Fig. 171) has a comparatively large caudate +lobe, but is chiefly remarkable for the peculiar shape of the Spigelian +lobe, which mainly consists of a thin strip of tissue, 8 inches long, ¾ +inch wide, and ¼ inch deep. The small intestine, in place of the villi of +_R. unicornis_, has throughout the greater part of its length a uniform +series of thin and nearly or quite continuous transverse foldings, like +the valvulæ conniventes of the human small intestine. There is no gland +behind the foot. The post-glenoid and post-tympanic processes of the +squamosal do not unite below the auditory meatus. The presence of a +lateral nasal diverticulum, like that of the Horses and Tapirs, has been +verified only in this species, although it doubtless occurs in the others. + +[Illustration: FIG. 171.—Posterior aspect of the liver of _Rhinoceros +sumatrensis_. _rc_, Right central lobe; _rl_, right lateral lobe; _lc_, +left central lobe; _ll_, left lateral lobe; _c_, caudate lobe; _sp_, +Spigelian lobe. (From Garrod, _Proc. Zool. Soc._ 1873, p. 102.)] + +_Atelodine Group._—In the adults the incisors and canines quite +rudimentary or entirely wanting. Nasal bones thick, rounded and truncated +in front. Well-developed anterior and posterior horns in close contact. +Skin without any definite permanent folds. + +The two well-marked existing species are peculiar to the African +continent. + +[Illustration: FIG. 172.—Common African Rhinoceros (_Rhinoceros +bicornis_).] + +The common Two-horned Rhinoceros, _R. bicornis_, is the smaller of the +two, with a pointed prehensile upper lip, and a narrow compressed deep +symphysis of the lower jaw. It ranges through the wooded and watered +districts of Africa, from Abyssinia in the north to the Cape Colony, but +its numbers are yearly diminishing, owing to the inroads of European +civilisation, and especially of English sportsmen. It feeds exclusively +upon leaves and branches of bushes and small trees, and chiefly frequents +the sides of wood-clad rugged hills. Specimens in which the posterior +horn has attained a length as great as, or greater than, the anterior +have been separated under the name of _R. keitloa_, but the characters of +these appendages are too variable to found specific distinctions upon. +The Common African Rhinoceros is far more rarely seen in menageries in +Europe than either of the three Oriental species, but one has lived in +the gardens of the London Zoological Society since 1868. The molar teeth +of this species are of the general type of those of _R. sondaicus_, +having no combing-plate to join the crotchet in those of the upper jaw. +The conch of the ear is much rounded at its extremity, and edged by a +fringe of short hairs; while the nostrils are somewhat rounded. The eye +is placed immediately below the posterior horn.[272] Both in this and the +following species the post-glenoid and post-tympanic processes of the +squamosal do not unite below the auditory meatus. Nothing is known of the +anatomy of the soft parts of either of them. + +Burchell’s or the Square-mouthed Rhinoceros (_R. simus_), sometimes +called the White Rhinoceros, though the colour (dark slate) is not +materially different from that of the last species, is the largest of the +whole group, and differs from all the others in having a square truncated +upper lip and a wide, shallow, spatulate symphysis to the lower jaw. In +conformity with the structure of the mouth, this species lives entirely +by browsing on grass, and is therefore more partial to open countries +or districts where there are broad grassy valleys between the tracts of +bush. It is only found in Africa south of the Zambesi, and of late years +has become extremely scarce, owing to the persecutions of sportsmen; +indeed, the time of its complete extinction cannot be far off. No +specimen of this species has ever been brought alive to Europe. Mr. F. C. +Selous[273] gives the following description of its habits from extensive +personal observation:— + +“The square-mouthed rhinoceros is a huge ungainly-looking beast, with +a disproportionately large head, a large male standing 6 feet 6 inches +at the shoulder. Like elephants and buffaloes they lie asleep during +the heat of the day, and feed during the night and in the cool hours of +early morning and evening. Their sight is very bad; but they are quick of +hearing, and their scent is very keen; they are, too, often accompanied +by rhinoceros birds, which, by running about their heads, flapping their +wings, and screeching at the same time, frequently give them notice of +the approach of danger. When disturbed they go off at a swift trot, which +soon leaves all pursuit from a man on foot far behind; but if chased by +a horseman they break into a gallop, which they can keep up for some +distance. However, although they run very swiftly, when their size and +heavy build is considered, they are no match for an average good horse. +They are, as a rule, very easy to shoot on horseback, as, if one gallops +a little in front of and on one side of them, they will hold their +course, and come sailing past, offering a magnificent broadside shot, +while under similar circumstances a prehensile-lipped rhinoceros will +usually swerve away in such a manner as only to present his hind-quarters +for a shot. When either walking or running, the square-mouthed rhinoceros +holds its head very low, its nose nearly touching the ground. When a +small calf accompanies its mother it always runs in front, and she +appears to guide it by holding the point of her horn upon the little +animal’s rump; and it is perfectly wonderful to note how in all sudden +changes of pace, from a trot to a gallop or _vice versâ_, the same +position is always exactly maintained. During the autumn and winter +months (_i.e._ from March to August) the square-mouthed rhinoceros is +usually very fat; and its meat is then most excellent, being something +like beef, but yet having a peculiar flavour of its own. The part in +greatest favour among hunters is the hump, which, if cut off whole and +roasted just as it is in the skin, in a hole dug in the ground, would, I +think, be difficult to match either for juiciness or flavour.” + +The molar dentition is of the type obtaining in _R. unicornis_, so that +in this respect _R. simus_ has the same relation to _R. bicornis_ as +is presented by _R. unicornis_ to _R. sondaicus_. The ear-conch of the +Square-mouthed Rhinoceros is very large, elongated, and pointed at its +extremity, which bears only a slight tuft of hair; it is much expanded +in the middle, and the lower portion has its edges united to form a +short tube. The nostrils have a long slit-like aperture; and the eye is +situated behind the posterior horn. + +_Extinct Species._—Using the generic term _Rhinoceros_ in its widest +signification, a very large number of fossil forms may be referred to it, +the earliest of which date from the Upper Eocene (Oligocene) Phosphorites +of Central France. Only a few of the more important of these types can, +however, be even mentioned in this place. + +In the Pliocene Siwaliks of India _R. sivalensis_ appears to have been +the direct ancestor of _R. sondaicus_; while _R. palæindicus_ was +probably nearly related to _R. unicornis_, although the upper molars had +not developed a combing-plate. + +_R. schleirmacheri_, of the Lower Pliocene of Europe, falls into the +Ceratorhine group, although differing from _R. sumatrensis_ by the union +of the post-glenoid and post-tympanic processes of the squamosal beneath +the auditory meatus. The Middle Miocene _R. sansaniensis_ was a closely +allied if not identical form. + +The Atelodine group was very widely spread in past epochs. Thus the +huge _R. platyrhinus_ of the Indian Pliocene, and the equally large _R. +antiquitatis_ of the Pleistocene of Europe, were specialised forms with +a dentition resembling that of _R. simus_, to which they were probably +allied. An upper molar of _R. antiquitatis_—the so-called Tichorine, or +Woolly Rhinoceros—is shown in the woodcut on p. 402. Of this species +nearly whole carcases, with the thick woolly external covering, have been +discovered associated with those of the Mammoth, preserved in the frozen +soil of the north of Siberia. In common with some other extinct species +it had a solid median wall of bone supporting the nasals, from which it +is inferred that the horns were of a size and weight surpassing that of +the modern species. In the Lower Pliocene of Attica _R. pachygnathus_ +appears to have been closely allied to _R. bicornis_. Several species +such as _R. leptorhinus_ (Fig. 173), _R. megarhinus_, and _R. etruscus_, +occur in the European Pleistocene which do not present a marked +relationship to any of the living forms. This group is also represented +in the Pleistocene of Southern India by the small _R. deccanensis_ and +_R. karnuliensis_. + +In the Upper Miocene, or Lower Pliocene, of North America numerous +Rhinoceroses with incisor teeth occur which have no nasal horn, although +in those forms of which the limbs are known the fore feet resembled +those of existing species in having only three digits. These species +have been generically separated as _Aphelops_, but so closely do they +resemble existing Rhinoceroses that at one time Professor Cope proposed +to refer the hornless female of _R. sondaicus_ (described by Lesson as +_R. inermis_) to the same genus. If these American types be included in +_Rhinoceros_ there seems no valid reason for separating the European +Lower Pliocene and Miocene forms described as _Aceratherium_, at least +some of which have four digits in the manus. This group is represented +in the Upper Eocene Phosphorites of France, and also by a very large +species in the Pliocene of India. Lastly, _R. minutus_, of the Lower +Miocene of France, and an allied North American species are distinguished +by carrying a pair of very small horns placed transversely across the +nasals, from which feature it has been proposed that they should be +separated genetically as _Diceratherium_. + +[Illustration: FIG. 173.—Skull of _Rhinoceros leptorhinus_, from the +Pleistocene of Essex. About ⅛ natural size.] + +_Extinct Generic Types._—The Tertiary deposits of different parts of the +world have yielded remains of many extinct forms more or less closely +related to the Rhinoceroses, and some of which should certainly be +included in the same family; although others perhaps form the types +of one or more distinct families. One of the most remarkable of these +extinct types is the huge _Elasmotherium_, from the Pleistocene of +Siberia, in which the dentition was reduced to two premolars and three +molars on either side of each jaw. The structure of the skeleton is +essentially rhinocerotic, the skull having an ossified nasal septum, +and a huge frontal prominence for the support of a very large horn. The +teeth are extremely hypsodont, with the enamel plicated to a remarkable +degree, and unlike those of _Rhinoceros_. The genus is evidently a very +specialised one. + +The other genera we have to notice are more generalised types. Of these +the North American _Hyracodon_, with the full typical number of teeth, +and without nasal horn, appears to connect the Rhinoceroses with the +Lophiodont _Hyrachyus_. The genera _Amynodon_ and _Metamynodon_ (Fig. +174), from the American Tertiaries, are forms allied to the Rhinoceroses, +with the full number of incisors and canines, and the hinder lobe of the +last upper molar not aborted. The lower canines are either upright, or +less proclivous than in the Rhinoceroses; in _Metamynodon_ the premolars +are reduced to ³⁄₂. Molar teeth from the Phosphorites of Central France, +described under the name of _Cadurcotherium_, are constructed on the +general plan of those of the Rhinoceroses, although distinguished by +their extreme narrowness; this type of tooth being very similar to that +found in _Homalodontotherium_ from Tertiary deposits in Patagonia. The +latter has the full number of teeth, without any diastema in the series. +Until we have some knowledge of the skeleton of these remarkable forms +nothing definite can be said as to their serial position. + +[Illustration: FIG. 174.—Right half of the palatal surface of the cranium +of _Metamynodon planifrons_, from the Upper Miocene of North America. +(After Scott and Osborn.)] + + +_Families_ LAMBDOTHERIIDÆ, CHALICOTHERIIDÆ, AND TITANOTHERIIDÆ. + +These families contain a large number of more or less nearly related +extinct types from Tertiary beds of both the Old and New Worlds, some +of which present most remarkable deviations from the ordinary Ungulate +structure. All are characterised by their brachydont molars, which depart +widely from the normal lophodont type. The upper molars consist of four +columns, of which the two external ones are expanded to form an outer +wall; the posterior pair being connected in some cases by an oblique +transverse ridge, while there may be traces of an anterior ridge. The +premolars are simpler. + +_Lambdotheriidæ._—This family is confined to the Upper Eocene and +Miocene of North America, where it is represented by _Lambdotherium_, +_Palæosyops_, and _Limnosyops_; it presents the normal type of foot +structure, and all the genera except the first have the full complement +of teeth. There were four digits in the manus. The last lower molar has +a third lobe. _Limnosyops_ differs from _Palæosyops_ in having two inner +columns to the last upper molar. + +[Illustration: FIG. 175.—Anterior and distal aspects of a phalangeal bone +of _Chalicotherium sivalense_. (From the _Palæontologia Indica_.)] + +_Chalicotheriidæ._—The genus _Chalicotherium_, which is found in the +Tertiaries of Europe, Asia, and North America, differs so remarkably +in the structure of the feet from all other Ungulates that it has +been proposed to regard it as the representative of a distinct order, +Ancylopoda. The molars are, however, almost indistinguishable from those +of the preceding and following families; while the cervical vertebræ +and portions of the limbs are of a Perissodactyle type. On the other +hand, the femur has lost its third trochanter; while the phalanges are +strangely modified, the terminal ones forming long curved claws, while +the others (Fig. 175) have strong ginglymoid distal articulations. +These phalanges were, indeed, long regarded as referable to Edentates, +being described in Europe as _Macrotherium_, and in the United States +as _Morotherium_ and _Moropus_. _Ancylotherium_, of the Grecian Pikermi +beds, is founded upon phalanges which indicate an allied genus. The +Indian species of _Chalicotherium_ is distinguished by the loss of the +incisors and the upper canine; while all the species want the first +premolar. + +_Titanotheriidæ._—This exclusively North American family includes +gigantic forms closely allied to the _Lambdotheriidæ_, but with the last +upper premolar as complex as the molars, and frequently with large bony +protuberances in the nasal region. The best known genus, _Titanotherium_ +(_Menodus_,[274] _Brontotherium_, _Symborodon_, _Allops_, etc.), may +either have the full complement of teeth, or the incisors may be reduced +to ²⁄₀. The canines and incisors are small, and there is no diastema +when the full dental series is developed. The skull is very like that of +the Rhinoceroses; but has a transverse pair of large bony prominences +on the nasal region, varying considerably in shape and size in the +different species, which in the living animal were probably covered with +horny sheaths. The third trochanter of the femur was aborted. These +huge animals—inferior in size only to the Elephant—appear to have been +abundant in the United States during the Miocene period. + + +_Family_ MACRAUCHENIIDÆ. + +This extinct South American family is best known by the genus +_Macrauchenia_, as represented by _M. patachonica_ and _M. boliviensis_, +which are apparently from Pleistocene formations. They are very singular +and specialised forms, quite out of the line of descent of any of the +existing Perissodactyles, and the steps by which they are connected +with the rest of the group have not yet been discovered. Of the larger +species, _M. patachonica_, the skeleton is completely known. It had the +full number of forty-four teeth, forming an almost uninterrupted series. +The cervical vertebræ resemble those of the Camels in the position of +the vertebrarterial canal, but the ends of the centra are flat, and not +opisthocœlous as in the allied forms. In some of the limb characters it +resembles the _Equidæ_, but in the articulation of the fibula with the +calcaneum it agrees with the Artiodactyles. The structure of the feet is, +however, distinctly Perissodactylate, there being three toes on each. The +teeth approximate to a Rhinocerotine structure; and the incisors have an +infolding of the enamel of their crowns, as in those of the Horses. The +nares open on the top of the skull, and it is probable that the muzzle +was produced into a short proboscis. Several other South American forms +have been referred to this family, some of which have received distinct +generic names, but further evidence is required before many of them can +be accepted. Possibly _Homalodontotherium_ should be placed here. + + +_Family_ PROTEROTHERIIDÆ. + +_Proterotherium._—Here may be noticed certain very remarkable +Perissodactyles from the South American Tertiaries, for which the name +_Proterotherium_ has been proposed. The cheek-teeth are so like those +of _Anchitherium_ that they have been described under that name. The +upper jaw has one pair of canine-like incisors and no canines, while the +lower jaw carries two pairs of incisors. In the skull the orbits were +completely closed, as in the Horses. The feet were tridactyle, like those +of _Hipparion_, but the tarsus was constructed on an Artiodactyle type. + + +SUBUNGULATA. + +By far the greater number of the Subungulata are extinct, and of many of +those whose former existence has been revealed, chiefly by the labours +of the American palæontologists, our knowledge is at present necessarily +imperfect, though daily extending. It will only be possible here to give +details of some of the more interesting or best-known forms. + +The characters by which the skeleton of the feet of the Subungulata +are distinguished from those of the Ungulata Vera have been already +mentioned on p. 275. In addition to these it may be observed that the +feet frequently have five functional digits, and may be plantigrade; +while the upper surface of the astragalus is generally flattened, instead +of presenting the strongly-marked pulley-like ridges and groove so +characteristic of the Ungulata Vera. + + +_Suborder_ HYRACOIDEA. + + +_Family_ HYRACIDÆ. + +[Illustration: FIG. 176.—_Hyrax capensis._] + +This division is constituted to receive a single family of mammals, the +affinities of which have long constituted a puzzle to zoologists. They +were first placed among the Rodents, to which animals their small size +and general appearance and habits give them much superficial resemblance. +Cuvier’s investigations into their anatomical structure, and especially +their dental characters, led him to place them among the Ungulates, near +the genus _Rhinoceros_, a position long accepted by many zoologists. +Further knowledge of their organisation and mode of development caused +Milne-Edwards, Huxley, and others to disassociate them from this +connection, and, failing to find any agreement with any other known +forms, to place them in an order entirely apart. Palæontology has thrown +no light upon the affinities of this anomalous and isolated group, as no +extinct animals possessing their distinctive characters have as yet been +discovered. + +[Illustration: FIG. 177.—Skull and dentition of _Dendrohyrax dorsalis_. × +⅔.] + +The dentition, according to the usual interpretation, consists only of +incisors and molars, the formula in all known species being _i_ ¹⁄₂, +_c_ ⁰⁄₀, _p_ ⁴⁄₄, _m_ ³⁄₃. The upper incisors have persistent pulps, +and are curved longitudinally, forming a semicircle as in Rodents. They +are, however, not flattened from before backwards as in that order, but +prismatic, with an antero-external, an antero-internal, and a posterior +surface, the first two only being covered with enamel; their apices are +consequently not chisel-shaped, but sharp pointed. They are preceded by +functional, rooted milk-teeth. The outer lower incisors, which should +perhaps be regarded rather as canines, have long tapering roots, but not +of persistent growth. They are straight, procumbent, with awl-shaped, +trilobed crowns. Behind the incisors is a considerable diastema. The +molars and premolars are all contiguous, and formed almost exactly on +the pattern of some of the Perissodactyle Ungulates. The hyoid arch is +unlike that of any known mammal. The dorsal and lumbar vertebræ are very +numerous, 28 to 30, of which 21 or 22 bear ribs. The tail is extremely +short. There are no clavicles. In the fore foot the three middle toes are +subequally developed, the fifth is present, but smaller, and the hallux +is rudimentary, although, in one species at least, all its normal bones +are present. The ungual phalanges of the four outer digits are small, +somewhat conical, and flattened in form. The carpus has a distinct os +centrale. There is a slight ridge on the femur in the place of a third +trochanter. The fibula is complete, thickest at its upper end, where +it generally ankyloses with the tibia. The articulation between the +tibia and astragalus is more complex than in other mammals, the end +of the malleolus entering into it. The hind foot is very like that of +_Rhinoceros_, having three well-developed toes. There is no trace of a +hallux, and the fifth metatarsal is represented only by a small nodule. +The ungual phalanx of the inner (or second) digit is deeply cleft, and +has a peculiar long curved claw, the others have short broad nails. The +stomach is formed upon much the same principle as that of the Horse +or Rhinoceros, but is more elongated transversely and divided by a +constriction into two cavities—a large left _cul de sac_, lined by a very +dense white epithelium and a right pyloric cavity, with a very thick, +soft, vascular lining. The intestinal canal (Fig. 178) is long, and has +an arrangement perfectly unique among mammals, indeed among vertebrated +animals, for, in addition to the ordinary short, but capacious and +sacculated cæcum (_cm_) at the commencement of the colon, there is, lower +down, an additional pair of large, conical, pointed, supplemental cæca +(_c_). The liver is much subdivided, and there is no gall-bladder. The +brain resembles that of the typical Ungulates far more than the Rodents. +The testes are permanently abdominal. The ureters open into the fundus +of the bladder, as in some Rodents. The female has six teats, of which +four are inguinal and two axillary; and the placenta is zonary, as in the +Elephant and Carnivora. + +[Illustration: FIG. 178.—Diagrammatic view of the alimentary canal +of _Hyrax capensis_, the intestines being somewhat abbreviated. _d_, +Duodenum; _i_, ileum; _cm_, cæcum; _c_, supplemental colic cæca; _r_, +rectum.] + +There are two distinct forms of Hyrax, differing both in structure and +habits, which may be accorded generic rank. + +_Hyrax._[275]—Molar teeth having the same pattern as those of +_Rhinoceros_. Interval between upper incisors less than the width of the +teeth. Lower incisors slightly notched at the cutting edge. Vertebræ: +C 7, D 22, L 8, S 6, C 6. Of this form the earliest known species, _H. +capensis_ (Fig. 176) is the type. There are several other species, as _H. +habessinicus_ and _syriacus_, from Eastern Africa and Syria. They inhabit +mountainous and rocky regions, and live on the ground. + +_Dendrohyrax._[276]—Molar teeth having the same pattern as _Palæotherium_ +(except that the third lower molar has but two lobes). Interval between +upper incisors exceeding the width of the teeth. Lower incisors with very +distinctly trilobed crowns. Vertebræ: C 7, D 21, L 7, S 5, C 10. The +members of this section frequent the trunks and large branches of trees, +sleeping in holes. There are several species, not distinctly defined, +from western and south Africa, as _D. arboreus_ and _D. dorsalis_. The +members of both groups appear to have a power like that possessed by the +Lizards called Geckos of clinging to vertical surfaces of rocks and trees +by the soles of their feet. + +It should be added that some writers separate three of the African +species usually included in _Hyrax_ (viz. _H. bocagei_, _H. bakeri_, and +_H. blainvillei_) under the designation of _Heterohyrax_.[277] + + +_Suborder_ PROBOSCIDEA. + +This name has been appropriated to a well-marked group of animals, +presenting some very anomalous characters, allied in many respects to +the typical Ungulata, but belonging neither to the Artiodactyle nor +Perissodactyle type of that order. It has been thought that they possess +some, though certainly not very close, affinities with the Rodentia, and +also with the Sirenia. It is certain, however, that the two species of +Elephant, which are the sole living representatives of the group, stand +quite alone among existing mammals, differing widely from all others +in many points of their structure. In some respects, as the skull, +proboscis, and dentition, they are highly specialised; but in others, +as in the presence of two anterior venæ cavæ and in the structure of +the limbs, they retain a low or generalised condition. A considerable +series of extinct forms, extending back through the Pliocene and Miocene +epochs, show the same type under different modifications, and in still +more generalised outlines; and certain forms from the Eocene of North +America, if their affinities are rightly interpreted, appear to link the +true Proboscidea to some unknown primitive type of Ungulata. + +The following are the principal characters common to existing, and, by +inference, to the extinct, Proboscidea. The nose extended into a long, +muscular, very flexible and prehensile proboscis, at the end of which +the nostrils are situated, and from which the name given to the group +is derived. The teeth consisting of ever-growing incisors of very great +size, but never exceeding one pair in each jaw, and often present in +one jaw only; no canines; large and transversely ridged molars. No +clavicles. Limbs strong, the upper segment, especially in the hind limb, +the longer. Radius and ulna distinct, the latter articulating extensively +with the carpus. Fibula and tibia distinct. Astragalus very flat on both +surfaces. Manus and pes short, broad, and massive, each with five toes, +though the outer pair may be more or less rudimentary, all encased in +a common integument, though with distinct, broad, short hoofs. Third +digit the largest. Two anterior venæ cavæ entering the right auricle. +Stomach simple. A capacious cæcum. Testes permanently abdominal. Uterus +bicornuate. Placenta non-deciduate and zonary. Mammæ two, pectoral. + +With regard to the teeth, the incisors,[278] which project largely out +of the mouth, and are commonly called “tusks,” are of an elongated +conical form, and generally curved. They are composed mainly of solid +dentine, the fine elastic quality and large mass of which renders it +invaluable as “ivory” for commerce and the arts. A peculiarity of the +dentine of most Proboscidea is that it shows, in transverse fractures or +sections, striæ proceeding in the arc of a circle from the centre to the +circumference in opposite directions, and forming by their decussations +curvilinear lozenges, as in the “engine-turning” of the case of a watch. +The enamel-covering in existing species is confined to the extreme +apex, and very soon wears off, but in some extinct species it forms +persistent longitudinal bands of limited breadth. The tusks have small +milk-predecessors, shed at an early age. + +The molar teeth present a remarkable series of modifications, from the +comparatively simple form in _Dinotherium_, with two or three strongly +pronounced transverse ridges and a normal mode of succession, to the +extremely complex structure and anomalous mode of replacement found in +the true Elephants. The intermediate conditions occur in the various +species of _Mastodon_. In this genus the enamel-covered transverse +ridges of each tooth are generally more numerous than in _Dinotherium_, +and often complicated by notches dividing their edge or by accessory +columns attached to them, but in the unworn tooth they stand out freely +on the surface of the crown, with deep valleys between (Fig. 179, I). +In the Elephants the ridges are still further increased in number, and +consequently narrower from before backwards, and are greatly extended +in vertical height, so that, in order to give solidity to what would +otherwise be a laminated or pectinated tooth, it becomes necessary to +envelop and unite the whole in a large mass of cement, which completely +fills up the valleys, and gives a general smooth appearance to the organ +when unworn; but as the wear consequent upon the masticating process +proceeds, the alternate layers of tissue of different hardness—cement, +dentine, and enamel—which are disclosed upon the surface form a fine and +very efficient triturating instrument. The modification of the tooth of +a Mastodon into that of an Elephant is therefore precisely the same in +principle as that of the molar of a Palæotherium into that of a Horse, +or of the corresponding tooth of one of the primitive Artiodactyles into +that of an Ox. The intermediate stages, moreover, even in the present +state of our knowledge, are so numerous that it is not possible to draw a +definite line between the two types of tooth structure (see Fig. 179, I, +II, III, IV). + +[Illustration: FIG. 179.—Longitudinal sections of the crown of a +molar tooth of various Proboscideans, showing stages in the gradual +modification from the simple to the complex form. I, _Mastodon +americanus_; II, _Elephas insignis_; III, _Elephas africanus_; IV, +_Elephas primigenius_. The dentine is indicated by transverse lines, the +cement by a dotted surface, and the enamel is black.] + +As regards the mode of succession, that of modern Elephants is, as +before mentioned, very peculiar. During the complete lifetime of the +animal there are but six molar teeth on either side of each jaw, with +occasionally a rudimentary one in front, completing the typical number +of seven. The last three represent the true molars of ordinary mammals; +those in front appear to be milk-molars, which are never replaced by +permanent successors, but the whole series gradually moves forwards in +the jaw, and the teeth become worn away and their remnants cast out in +front, while development of others proceeds behind. The individual teeth +are so large, and the processes of growth and destruction by wear take +place so slowly, that not more than one, or portions of two, teeth are +ever in place and in use on either side of each jaw at one time, and the +whole series of changes coincides with the usual duration of the animal’s +life. On the other hand, the Dinotherium, the opposite extreme of the +Proboscidean series, has the whole of the molar teeth in place and use +at one time, and the milk-molars are vertically displaced by premolars +in the ordinary fashion. Among Mastodons transitional forms occur in +the mode of succession as well as in structure, many species showing a +vertical displacement of one or more of the milk-molars, and the same has +been observed in one extinct species of Elephant (_E. planifrons_) as +regards the posterior of these teeth. + +All known Proboscideans are animals of comparatively large dimensions, +and some are the most colossal of land mammals. The head is of great +proportionate size; and, as the brain case increases but little in bulk +during growth, while the exterior wall of the skull is required to +be of great superficial extent to support the trunk and the huge and +ponderous tusks, and to afford space for the attachment of muscles of +sufficient size and strength to wield the skull thus heavily weighted, +an extraordinary development of air-cells takes place in the cancellous +tissue of nearly all the bones of the cranium (Fig. 180). These cells +are not only formed in the walls of the cranium proper, but are also +largely developed in the nasal bones and upper part of the premaxillæ and +maxillæ, the bones forming the palate and the basicranial axis, and even +extend into the interior of the ossified mesethmoid and vomer. Where two +originally distinct bones come into contact, the cells pass freely from +one to the other, and almost all the sutures become obliterated in old +animals. The intercellular lamellæ in the great mass which surrounds +the brain cavity superiorly and laterally mostly radiate from the inner +to the outer table, but in the other bones their direction is more +irregular. Like the similar but less developed air-cells in the skulls +of many other mammals, they all communicate with the nasal passages, +and they are entirely secondary to the original growth of the bones, +their development having scarcely commenced in the new-born animal, and +they gradually enlarge as the growth of the creature proceeds towards +maturity. The nasal bones are very short, and the anterior narial +aperture is situated high in the face. The zygomatic arch is slender and +straight, the jugal bone being small, and forming only the middle part of +the arch, the anterior part of which (unlike that of typical Ungulates) +is formed only by the maxilla. The maxillo-turbinals are but rudimentary, +the elongated proboscis supplying their place functionally in warming and +clearing from dust the inspired air. + +[Illustration: FIG. 180.—A vertical section of the skull of the African +Elephant (_Elephas africanus_) taken to the left of the middle line, and +including the vomer (_Vo_) and the mesethmoid (_ME_). _an_, Anterior, +and _pn_, posterior narial aperture. ¹⁄₁₂ natural size. (From Flower’s +_Osteology of the Mammalia_.)] + +The neck is very short. The limbs are long and stout, and remarkable for +the great length of the upper segment (especially the femur) as compared +with the distal segment, the manus, and pes. It is owing to this and +the vertical position of the femur that the knee-joint in the hind leg +is placed much lower, and is more conspicuous externally than in most +quadrupedal mammals; and this having been erroneously compared with the +hock-joint or ankle of typical Ungulates, the popular fallacy that the +joints of the Elephant’s leg bend in a contrary direction to that of +other mammals has arisen. There is no round ligament in the hip-joint, +or third trochanter to the femur. The radius and ulna are distinct, +though fixed in a crossed or prone position. The fibula also is quite +distinct from the tibia. The feet are short and broad, the carpal and +tarsal bones being very square, with flattened surfaces for articulation; +the astragalus especially differs from that of typical Ungulates in its +flatness, in the absence of a distinct pulley-like articular surface +at either extremity, and in having no articular facet for the cuboid. +The fibula articulates with the calcaneum, as in Artiodactyles. Of +the five toes present on each extremity (see Fig. 98), the middle one +is somewhat the largest, and the lateral ones smallest, and generally +wanting (especially in the hind foot) the complete number of phalanges. +The ungual phalanges are all small, irregular in form, and late in +ossification. The whole are encased in a common integument, with a flat, +subcircular, truncated sole, the only external indication of the toes +being the broad oval nails or hoofs arranged in a semicircle around the +front edge of the sole. The hind foot is smaller and narrower than the +front. The liver is small and simple, and there is no gall-bladder. In +form the brain resembles that of the Rodents and other lower orders +of mammals, the cerebellum being entirely behind and uncovered by the +cerebrum, but the hemispheres of the latter are richly convoluted. + +The Proboscidea are exclusively vegetable feeders, living chiefly on +leaves and young branches of forest trees and various kinds of herbage, +which they gather and convey to their mouth by the very mobile proboscis, +an organ which combines in a marvellous manner strength with dexterity +of application, and is a necessary compensation for the shortness and +inflexibility of the neck, as by it many of the functions of the lips +of other animals are performed. By its means the Elephant is enabled +to drink without bending the head or limbs; the end of the trunk being +dipped into the stream or pool, a forcible inspiration fills the two +capacious air-passages in its interior with water, which, on the tip of +the trunk being turned upwards and inserted into the mouth, is ejected +by a blowing action, and swallowed; or if the animal wishes to refresh +and cool its skin, it can throw the water in a copious stream over any +part of its surface. Elephants can also throw dust and sand over their +bodies by the same means and for the same purpose, and wild animals +have been frequently observed fanning themselves with leafy boughs held +in the trunk. The species are at present limited in their geographical +distribution to the Ethiopian and Oriental regions, but they formerly had +a far more extensive range. + + +_Family_ ELEPHANTIDÆ. + +Cheek-teeth succeeding one another in an arc of a circle, and portions of +only two, or at most three, of the hinder teeth in use at any one time. +Premolars frequently lost, and in any case of no functional importance. + +_Elephas._[279]—Dentition: _i_ ¹⁄₀, _c_ ⁰⁄₀, _dm_ ³⁄₃, _m_ ³⁄₃ = 26. The +incisors variable, but usually of very large size, especially in the +male sex, directed somewhat outwards, and curved upwards, without enamel +except on the apex before it is worn. The molars composed of numerous +flattened enamel-covered plates or ridges of dentine, projecting from +a common many-rooted base, surrounded and united together by cement, +and extending straight across the crown, without (in most forms) any +median division into inner and outer columns. The number of plates +increases from the anterior to the posterior molar in regular succession, +varying in the different species, but the third and fourth (or the last +milk-molar and the first true molar), and these only, have the same +number of ridges, which always exceeds five. Premolars nearly always +wanting. Skull of adult very high and globular. Mandible ending in front +in a short, deflected, and spout-like symphysis. Vertebræ: C 7, D 19-21, +L 3-4, S 4, C 26-33. + +The existing species of the genus differ so much that they have been +referred by some writers to distinct genera; fossil forms show, however, +such a transition from the one to the other that it is scarcely possible +to regard them even as the representatives of distinct groups. + +[Illustration: FIG. 181.—Grinding surface of a half-worn lower molar of +the Indian Elephant (_Elephas indicus_). _d_, Dentine; _e_, enamel; _c_, +cement. (From Owen.)] + +In the well-known Indian or Asiatic Elephant (_E. indicus_) the average +number of plates of the six successive molar teeth is expressed by the +“ridge-formula,” 4, 8, 12, 12, 16, 24. The plates are compressed from +before backwards, the anterior and posterior surfaces (as seen in the +worn grinding face of the tooth, Fig. 181) being nearly parallel. Ears of +moderate size. Upper margin of the end of the proboscis developed into +a distinct finger-like process, much longer than the lower margin. Five +nails on the fore feet, and four (occasionally five) on the hind feet. + +[Illustration: FIG. 182.—Grinding surface of a partially worn right upper +molar of the African Elephant (_Elephas africanus_). Letters as in the +preceding figure. The left side of the figure is the front of the tooth, +and the lower side the outer border. (From Owen.)] + +This species inhabits in a wild state the forest lands of India, Burma, +the Malay Peninsula, Cochin China, Ceylon, and Sumatra. The elephants +from the last-named islands, presenting some variations from those of +the mainland, have been separated under the name of _E. sumatranus_, but +the distinction has not been satisfactorily established. The appearance +of the Asiatic Elephant is familiar to all. Though rarely breeding in +captivity, it has been domesticated from the most remote antiquity, and +is still extensively used in the East as a beast of burden. In the wild +state it is gregarious, associating in herds of ten, twenty, or more +individuals, and though it may, under certain circumstances, become +dangerous, it is generally inoffensive and even timid, fond of shade and +solitude and the neighbourhood of water. The height of the male at the +shoulder when full grown is usually from 8 to 10 feet, but occasionally +as much as 11. The female is somewhat smaller. + +[Illustration: FIG. 183.—African Elephant (_Elephas africanus_). From a +young specimen in the London Zoological Gardens.] + +In the African Elephant (_E. africanus_) the molars (Fig. 182) are of +coarse construction, with fewer and larger plates and thicker enamel. +Ridge-formula: 3, 6, 7, 7, 8, 10. The plates not flattened, but thicker +in the middle than at the edges, so that their worn grinding surfaces +are lozenge-shaped. Ears very large. The upper and lower margins of the +end of the trunk forming two nearly equal prehensile lips. But three +hoofs on the hind foot. This species now inhabits the wooded districts +of the whole of Africa south of the Sahara, except where it has been +driven away by human settlements. Fossil remains of Pleistocene age, +undistinguishable specifically, have been found in Algeria, Spain, and +Sicily. It was trained for war and show by the ancient Carthaginians and +Romans, and recent experience of the species in captivity in England +shows that it is as intelligent as its Asiatic relative, if not more so, +while surpassing it in courage, activity, and obstinacy. Nevertheless, +in modern times, no people in Africa have been sufficiently civilised +or enterprising to care to train it for domestic purposes. It is hunted +chiefly for the sake of the ivory of its immense tusks, of which it +yields the principal source of supply to the European market, and the +desire to obtain which is rapidly leading to the extermination of the +species. In size the male African elephant often surpasses that of Asia, +but the female is usually smaller. The circumference of the fore foot is +half the height at the shoulder, a circumstance which enables the hunters +to judge from the footprints the exact size of the animals of which +they are in pursuit. The African Elephant also differs from its Indian +congener in having tusks in both sexes, whereas in the latter the male +only is so armed. Moreover, the eye is relatively larger, the forehead +more convex, and the colour somewhat darker. Whereas the Indian Elephant +frequents the depths of forests and seldom leaves their shade during the +daytime, the following account by Sir Samuel Baker indicates different +habits in the African species. This traveller observes: “In Africa, the +country being generally more open than in Ceylon, the Elephant remains +throughout the day either beneath a solitary tree or exposed to the sun +in the vast prairies, where the thick grass attains a height of from +nine to twelve feet. The general food of the African Elephant consists +of the foliage of trees, especially mimosas. Many of the mimosas are +flat-headed, about thirty feet high, and the richer portion of the +foliage confined to the crown. Thus the Elephant, not being able to +reach to so great a height, must overturn the tree to obtain the coveted +food. The destruction caused by a herd of Elephants in a mimosa forest +is extraordinary, and I have seen trees uprooted of so large a size that +I am convinced no single elephant could have overturned them. I have +measured trees four feet six inches in circumference and about thirty +feet high uprooted by elephants. The natives have assured me that the +elephants mutually assist each other, and that several engage together in +the work of overturning a large tree.” + +[Illustration: FIG. 184.—Restored skeleton of the Mammoth (_Elephas +primigenius_). From Tilesius in _Mém. Acad. Imp. Sc. St. Pétersbourg_, +vol. v. (1815). _s_, Scapula; _h_, humerus; _r_, radius; _u_, ulna; +_c_, carpus; _rs_, ischium; _f_, femur; _t_, tibia; _fi_, fibula; _ta_, +tarsus.] + +_Extinct Species of Elephant._—Abundant remains of Elephants are found +embedded in alluvial gravels, or secreted in the recesses of caves, +into which they have been washed by streams and floods, or dragged as +food by Hyænas and other carnivorous inhabitants of these subterranean +dens. Such remains belonging to the Pleistocene and Pliocene periods +have been found in many parts of Europe, including the British Isles, +in North Africa, throughout the North American continent from Alaska to +Mexico, and extensively distributed in Asia, where the deposits of the +sub-Himalayan Siwalik Hills, and equivalent deposits in the Punjab, Perim +Island,[280] and Burma, belonging to the earliest Pliocene, are rich +in the remains of Elephants of varied form. These species are chiefly +known and characterised at present by the skulls and teeth; some of the +latter resemble the existing Indian and some the African type, but the +majority are between the two, and make the distinction between the two +existing species as of generic importance quite impracticable. Others +again approach so closely in the breadth and coarseness of the ridges +and paucity of cement to _Mastodon_ as to have been placed by some +zoologists in that genus. These form the subgenus called _Stegodon_ by +Falconer, and may be regarded as a distinct group of the genus. + +Among the best known extinct Elephants is _E. primigenius_, the +Mammoth,[281] very closely resembling the existing Indian species, and +one of the most recently extinct and extensively distributed of all the +fossil forms. Probably no animal which has not survived to the historic +period has left such abundant and well-preserved evidence of its former +existence. The discovery of immense numbers, not only, as in the case +of most extinct creatures, in the form of fragmentary bones and teeth, +but often as more or less nearly entire carcases, or “mummies,” as they +may be called, with the flesh, skin, and hair _in situ_, in the frozen +soil of the tundras of Northern Siberia, has for a long time given great +interest to the species, and been the cause of many legendary stories +among the natives of the lands in which they occur. Among these one of +the most prevailing is that the Mammoth was, or still is, an animal which +passes its life habitually in burrows below the surface of the ground, +and immediately dies if by any chance it comes into the upper air. + +Of the whole group the Mammoth is in many respects, as in the size and +form of the tusks, and especially the characters of the molar teeth, +the farthest removed from the primitive Mastodon-like type, while its +nearest surviving relative, _E. indicus_, has retained the slightly more +generalised characters of the Mammoth’s contemporaries of more southern +climes, _E. columbi_ of America, and _E. armeniacus_ of the Old World, +if, indeed, it can be specifically distinguished from them. + +The tusks or upper incisor teeth were doubtless present in both sexes, +but probably of smaller size in the female. In the adult males they +often attained the length of from 9 to 10 feet measured along the outer +curve. Upon leaving the head they were directed at first downwards and +outwards, then upwards and finally inwards at the tips, and generally +with a tendency to a spiral form not seen in other species of Elephant. +Different specimens, however, present great variations in curve, from +nearly straight to an almost complete circle. + +It is chiefly by the characters of the molar teeth that the various +extinct modifications of the Elephant type are distinguished. Those of +the Mammoth (Fig. 185) differ from the corresponding organs of allied +species in the great breadth of the crown as compared with the length, +the narrowness and close approximation of the ridges, the thinness of the +enamel and its straightness, parallelism, and absence of “crimping,” +as seen on the worn surface, or in a horizontal section of the tooth. +Dr. Falconer gave the prevailing “ridge-formula” as 4, 8, 12, 12, 16, +24. Dr. Leith Adams, working from more abundant materials, has shown, +however, that the number of ridges of each tooth, especially those at +the posterior end of the series, is subject to very great individual +variation, ranging in each tooth of the series within the following +limits: 3 to 4, 6 to 9, 9 to 12, 9 to 15, 14 to 16, 18 to 27, excluding +the small plates called talons at each end of the tooth. Besides these +variations in the number of ridges or plates of which each tooth is +composed, the thickness of the enamel varies so much as to have given +rise to a distinction between a “thick-plated” and a “thin-plated” +variety—the latter being most prevalent among the specimens from the +Arctic regions, and most distinctively characteristic of the species. +From the specimens with thick enamel plates the transition to the other +species or varieties mentioned above, including _E. indicus_, is almost +imperceptible. + +[Illustration: FIG. 185.—Grinding surface of upper molar of the Mammoth +(_Elephas primigenius_). _c_, Cement; _d_, dentine; _e_, enamel. (From +Owen.)] + +The bones of the skeleton generally more resemble those of the Indian +Elephant than of any other known species, but the skull differs in the +narrower summit, narrower temporal fossæ, and more prolonged incisive +sheaths required to support the roots of the enormous tusks. Among the +external characters by which the Mammoth was distinguished from either +of the existing species of Elephant was the dense clothing, not only +of long coarse outer hair, but also of close woolly under hair, of a +reddish-brown colour, evidently in adaptation to the colder climate +which it inhabited. This character, for a knowledge of which we are +indebted to the well-preserved remains found in Northern Siberia, is also +represented in the rude but graphic drawings of prehistoric age found in +caverns in the south of France.[282] In size different individuals varied +considerably, but the average height does not appear to have exceeded +that of either of the existing species of Elephant. + +The geographical range of the Mammoth was very extensive. There is +scarcely a county in England in which some of its remains have not been +found either in alluvial deposits of gravel or in caverns, and numbers +of its teeth are from time to time dredged up from the bottom of the sea +by the fishermen who ply their trade in the German Ocean, having been +washed out of the water-worn cliffs of the eastern counties of England. +In Scotland and Ireland its remains are less abundant, but they have been +found in vast numbers at various localities throughout the greater part +of Central Europe (as far south as Santander in Spain and Rome), Northern +Asia, and the northern part of the American continent, though the exact +distribution of the Mammoth in the New World is still a question of +debate. It has not hitherto been met with in any part of Scandinavia or +Finland. + +In point of time, the Mammoth belongs exclusively to the Pleistocene +epoch, and it was undoubtedly contemporaneous with man in France, and +probably elsewhere. There is evidence to show that it existed in Britain +before, during, and after the glacial period. + +As before indicated, it is in the northern part of Siberia that its +remains have been found in the greatest abundance, and in quite +exceptional conditions of preservation. For a very long period there +has been from that region a regular export of Mammoth ivory in a state +fit for commercial purposes, both eastward to China and westward to +Europe. In the middle of the tenth century an active trade was carried +on at Khiva in fossil ivory, which was fashioned into combs, vases, and +other objects, as related by Abu’l Kásim, an Arab writer of that period. +Middendorff reckoned that the number of tusks which have yearly come into +the market during the last two centuries has been at least a hundred +pairs, and Nordenskiöld, from personal observation, considers this +calculation as probably rather too low than too high. They are found at +all suitable places along the whole line of the shore between the mouth +of the Obi and Behring Straits, and the farther north the more numerous +do they become, the islands of New Siberia being now one of the most +favourite collecting localities. The soil of Bear Island and of Liachoff +Islands is said to consist only of sand and ice with such quantities of +Mammoth bones as almost to compose its chief substance. The remains are +not only found around the mouths of the great rivers, as would be the +case if the carcases had been washed down from more southern localities +in the interior of the continent, but are imbedded in the frozen soil in +such circumstances as to indicate that the animals had lived not far from +the localities in which they are now found, and they are exposed either +by the melting of the ice in unusually warm summers or by the washing +away of the sea cliffs or river banks by storms or floods. In this way +the bodies of more or less nearly perfect animals, often standing in the +erect position, with the soft parts and hairy covering entire, have been +brought to light. + +References to the principal recorded discoveries of this kind, and to the +numerous speculations to which they have given rise, both among ignorant +peasants and learned academicians, will be found in Nordenskiöld’s +_Voyage of the Vega_ (English translation, vol. i. 1881, p. 398 _sq._) +and a series of papers in the _Geological Magazine_ for 1880 and 1881, +by H. H. Howorth, as well as in a separate work on the Mammoth by the +same writer. For the geographical distribution and anatomical characters, +see Falconer’s _Palæontological Memoirs_, vol. ii. 1868; Boyd Dawkins, +“_Elephas primigenius_, its Range in Space and Time,” _Quart. Journ. +Geol. Soc._ xxxv. p. 138 (1879); and Leith Adams, “Monograph of British +Fossil Elephants,” part ii., _Palæontographical Society_ (1879). + +_E. antiquus_, of the European Pleistocene, has a lower ridge-formula +than in the Mammoth, the molars being narrower, and approximating to +those of the African Elephant in structure. Small allied forms occur in +the rock-fissures and caverns of Malta, and have been described as _E. +mnaidriensis_ and _E. melitensis_; some of the individuals of the latter +not exceeding 3 feet in height. The European _E. meridionalis_ is a +southern form of somewhat earlier age, very common in the Upper Pliocene +of Italy and France, and also in the so-called Forest-bed of the Norfolk +coast. It attained very large dimensions, its height being estimated at +upwards of 15 feet. The ridge-formula is lower than in _E. antiquus_, the +molars are broad, with the worn enamel-discs generally expanded in the +middle, and the enamel itself is crenulated. + +Elephant remains are very abundant in the Pleistocene and Pliocene +deposits of India, those from the latter beds being the oldest +representatives of the genus. Of these the Pleistocene _E. namadicus_ +appears closely allied to _E. antiquus_, from which it is distinguished +by a bold ridge across the forehead. Among the Pliocene forms _E. +hysudricus_ may be an ancestral type allied to the Indian Elephant; +while _E. planifrons_ is closely related to _E. meridionalis_, although +retaining the ancestral feature of developing premolars. + +The Stegodont group is peculiar to the eastern parts of the Old World, +and, as already observed, connects the true Elephants intimately with +the Mastodons. The molars (Fig. 179, II) are characterised by the +lowness of the ridges, while the intervening valleys may have but little +cement, and there may be a more or less distinct longitudinal groove +in the crown dividing each ridge into an inner and an outer moiety. In +species like _E. insignis_ the ridge-formula is nearly the same as in +_E. meridionalis_, but in _E. clifti_ some of the molars carry only six +ridges, and premolars were present, so that we thus have such a complete +transition to the next genus that it is very difficult to know where to +draw the line between the two. + +_Mastodon._[283]—Dentition: _i_ ¹⁄₁₋₀, _c_ ⁰⁄₀, _dm_ ³⁄₃, _m_ ³⁄₃. Upper +incisors large, as in _Elephas_, sometimes with longitudinal bands of +enamel, more or less spirally disposed. Lower incisors variable; when +present comparatively small and straight, sometimes persistent, sometimes +early deciduous, and in some species never present. Grinding surface of +molars with transverse ridges, the summits of which are divided more +or less into conical or mammillary cusps, and often with secondary or +additional cusps between and clustering against the principal ridges; +enamel thick; cement very scanty, never filling up the interspaces +between the ridges. The third, fourth, and fifth cheek-teeth (_i.e._ the +last milk-molar, and the first and second molars) having the same number +of ridges,[284] which never exceeds five. + +In the upper jaw the incisors, though of large size, were apparently +never so much curved as in some species of Elephant, and they often +have longitudinal bands of enamel, more or less spirally disposed upon +their surface, which are not met with in Elephants. Lower incisors were +present throughout life in some species, which have the symphysis of the +lower jaw greatly elongated to support them (as in _M. angustidens_, _M. +pentilici_, and _M. longirostris_). In the common North American species +(_M. americanus_) the mandibular symphysis is short, but it may have a +small incisor on one side. In other species no inferior tusks have been +found, at all events in adult life (see figure of _M. arvernensis_). + +The molar teeth increase in size from before backwards, but as many as +three of these teeth may be in place in each jaw at one time. There is +in many species a true vertical succession, affecting either the third, +or the third and second, or (in _M. productus_) the first, second, and +third of the six molariform teeth. These three are therefore reckoned as +milk-molars, and their successors as premolars, while the last three, +which are never changed, correspond to the true molars of those animals +in which the typical dentition is fully developed. The study of the mode +of succession of the teeth in the different species of Mastodons is +particularly interesting, as it exhibits so many stages of the process +by which the very anomalous dentition of the modern Elephants may have +been derived by gradual modification from the typical heterodont and +diphyodont dentition of the ordinary mammal. It also shows that the +anterior molars of Elephants do not correspond to the premolars of other +Ungulates, but to the milk-molars, the early loss of which in consequence +of the peculiar process of horizontal forward-moving succession does +not require, or allow time for, their replacement by premolars. It must +be noted, however, that, in the Mastodon in some respects the least +specialised in tooth-structure, the _M. americanus_ of North America, no +vertical succession of the molars has yet been observed, although vast +numbers of specimens have been examined. + +[Illustration: FIG. 186.—Restoration of the skeleton of _Mastodon +arvernensis_, from the Pliocene of Europe, (After Sismonda.)] + +The Mastodons have fewer ridges on their molar teeth than the +Elephants; the ridges are also less elevated, wider apart, have a +thicker enamel-covering, and scarcely any cement filling up the space +between them. Sometimes (as in _M. americanus_) the ridges are simple +transverse wedge-shaped elevations, with straight or concave edges. In +other species the summits of the ridges are more or less subdivided into +conical cusps, and may have accessory cusps clustering around them (as +in _M. americanus_, see Fig. 187). When the apices of these are worn by +mastication, their surfaces present circles of dentine, surrounded by a +border of enamel, and as the attrition proceeds different patterns are +produced by the union of the bases of the cusps, a trilobed or trefoil +form being characteristic of some species (Fig. 188). + +[Illustration: FIG. 187.—Oblique side and crown view of the last upper +molar of _Mastodon arvernensis_. (From Owens.)] + +As already mentioned, certain of the molariform teeth of the middle of +the series in Mastodons have the same number of principal ridges, those +in front of them having fewer and those behind a greater number. These +teeth were distinguished as “intermediate” molars by Dr. Falconer, and +are three in number, namely the last milk-molar and the first and second +true molars (or the third, fourth, and fifth of the whole series). The +number of ridges on these intermediate molars is nearly always three or +four, and the tooth in front has usually one fewer and that behind one +more, so that the ridge-formula of most Mastodons can be reduced either +to 1, 2, 3, 3, 3, 4, or 2, 3, 4, 4, 4, 5. The former characterises the +section called _Trilophodon_ (of which an intermediate molar is shown in +Fig. 188), and the latter that called _Tetralophodon_ by Dr. Falconer. +These divisions are very useful, as under one or the other all the +present known species of Mastodon can be ranged, but observations upon a +larger number of individuals have shown that the number of ridges upon +the teeth is not quite so constant as implied by the formulæ given above. +Their exact enumeration is even difficult in many cases, as “talons” or +small accessory ridges at the hinder end of the teeth occur in various +stages of development, until they take on the character of true ridges. +Transitional conditions have also been shown, at least in some of the +teeth, between the trilophodont and the tetralophodont forms, and again +between the latter and what has been called a “pentalophodont” type, +which leads on towards the condition of dental structure characteristic +of the true Elephants. + +[Illustration: FIG. 188.—Grinding surface of the partially worn last left +lower milk-molar of _Mastodon angustidens_, from the Upper Miocene of +India. The lower side of the figure is the outer border of the tooth.] + +The range of the genus _Mastodon_ in time was from the middle of the +Miocene period to the end of the Pliocene in the Old World, when it +became extinct; but in America several species—especially the one best +known, owing to the abundance of its remains, which has been variously +called _M. americanus_, _M. ohioticus_, and _M. giganteus_—survived to a +late Pleistocene period. + +The range in space will be best indicated by the following list +of some of the better known species. (1) Trilophodont series—_M. +angustidens_,[285] _borsoni_, _pentelici_, _turiensis_, from Europe; _M. +falconeri_ and _pandionis_, from India; _M. americanus_, _obscurus_, and +_productus_, North America; and _M. cordillerum_ and _humboldti_, South +America. (2) Tetralophodont series—_M. arvernensis_, _M. longirostris_, +from Europe; _M. latidens_, _sivalensis_, and _perimensis_, from +India; _M. mirificus_, from North America. _Mastodon arvernensis_ and +_M. longirostris_, together with a trilophodont species, occur in the +crag-deposits of Norfolk and Suffolk. + + +_Family_ DINOTHERIIDÆ. + +An extinct family distinguished from the _Elephantidæ_ by the whole +series of permanent cheek-teeth being in use at the same time. + +[Illustration: FIG. 189.—Skull of _Dinotherium giganteum_, from the +Lower Pliocene of Eppelsheim, Hessen-Darmstadt. (After Kaup.) _p_, 3, 4, +premolars; 1, 2, 3, molars.] + +_Dinotherium._[286]—Dentition of adult: _i_ ⁰⁄₁, _c_ ⁰⁄₀, _p_ ²⁄₂, +_m_ ³⁄₃ = 22; all present at the same time, there being no horizontal +succession, but the premolars replacing milk-teeth in the ordinary +manner. The presence or absence of upper incisors has not yet been +clearly ascertained. Lower incisors large, conical, descending, and +slightly curved backwards, implanted in a greatly thickened and deflected +beak or prolongation of the symphysis. In section they do not show the +decussating striæ characteristic of Mastodons and Elephants. Crowns of +molars carrying strong transverse, crenulated ridges, with deep valleys +between, much resembling the lower ones of the Tapirs. Ridge-formula of +the permanent molar series: 2, 2, 3, 2, 2. The three ridges of the first +true molar are constant in both upper and lower jaws, although it is +quite an anomalous character among Proboscideans for this molar to have +more ridges than those which come behind it. The last milk-molar has also +three ridges, the penultimate but two. The cranium is much depressed, +with comparatively little development of air-cells. The remainder of +the skeleton is imperfectly known, but apparently agrees in its general +character with that of the other Proboscideans. + +Remains of _Dinotherium giganteum_, an animal of elephantine proportions, +strikingly characterised by the pair of huge tusks descending nearly +vertically from the front of the lower jaw, were first discovered at +Eppelsheim, near Darmstadt, and described by Kaup. They have since been +met with in various Lower Pliocene and higher Miocene formations in the +south of Germany, France, Greece, and Asia Minor. Closely allied forms +also occur in the Lower Pliocene and Upper Miocene of India, but none are +known from America. + + +_Suborder_ AMBLYPODA. + +_Uintatherium._[287]—Among the most remarkable of the comparatively +recent discoveries in the higher Eocene formations of the western +states of North America has been one of a group of animals of huge +size, approaching that of the largest existing Elephants, presenting a +combination of characters quite unlike those known among other recent or +extinct creatures, and of which there were evidently many species living +contemporaneously, but all of which became extinct before the close of +the Eocene period. To form some idea of their appearance, we must imagine +animals very elephantine in general proportions and in the structure of +their limbs. The feet had five short toes. The tail, as in the Elephants, +was long and slender, but the neck, though still short, was not so much +abbreviated as in the Proboscideans, and there is no evidence that these +animals possessed a trunk. The head differed greatly from that of the +Elephants, being long and narrow, more like that of a Rhinoceros, and, +as in that animal, was elevated behind into a great occipital crest, +and it had developed upon its upper surface three pairs of conspicuous, +laterally diverging protuberances—one pair in the parietal region, +one on the maxillaries in front of the orbits, and one (much smaller) +near the fore part of the elongated nasal bones. Whether these were +merely covered by bosses of callous skin, as the rounded form and +ruggedness of their extremities would indicate, or whether they formed +the bases of attachment for horns of still greater extent, like those +of the Rhinoceros or of the Cavicorn Ruminants, can only be a matter +of conjecture. There were no upper incisors, but usually three on each +side below, of comparatively small size, as was also the lower canine. +A huge, compressed, curved, sharp-pointed canine tusk, very similar in +form and position to that of the Musk-Deer, descended from each side of +the upper jaw. These were present in both sexes, but very much smaller +in the female, as was also the flange-like process of the lower jaw by +which they were guarded. Behind these, and at some distance from them, +were on each side above and below six cheek-teeth, of comparatively +small size, placed in continuous series, each with a pair of oblique +ridges conjoined internally and diverging externally in a V-like manner, +and provided with a stout basal cingulum. The normal dental formula was +therefore _i_ ⁰⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃ = 34; and the dentition had +thus already attained a remarkable degree of specialisation, although the +brain was smaller and more rudimentary in characters than in almost any +other known mammal. In its comparative length and the absence of a third +trochanter the femur of these animals resembles that of the Proboscidea. +The first discovered evidences of the existence of animals of this group +were described by Leidy in 1872, under the name of _Uintatherium_ (from +the Uinta mountains, near which they were found). Subsequently the +names _Dinoceras_, _Tinoceras_, _Loxolophodon_, etc., have been applied +to various members of the group, but the characters by which they are +distinguished do not seem of sufficient importance to allow of their +separation from the type genus _Uintatherium_.[288] + +[Illustration: FIG. 190.—Skeleton of _Uintatherium mirabile_. ¹⁄₃₀ +natural size. (From Marsh, _Am. Journ. Sci._ vol. xii. p. 2.)] + +_Coryphodon._[289]—Another interesting form referred to this suborder is +_Coryphodon_, which appears to connect the _Uintatheriidæ_ with the most +primitive Perissodactyla. It was first described by Owen in 1846 from a +fragment of a jaw from the London Clay. Other remains were afterwards +discovered in France, and lately in great abundance, indicating many +species from the size of a Tapir to that of a Rhinoceros, in the Lower +and Middle Eocenes of New Mexico and Wyoming in the United States. +_Coryphodon_ had forty-four teeth; the canines of both jaws were large +and sharp pointed, and the molars had strongly pronounced oblique +ridges. The general proportions were those of a Bear, but the tail was +of moderate length, and the feet short and wide. The femur had a third +trochanter; and the cranium was devoid of protuberances. The genus should +be regarded as the type of a distinct family _Coryphodontidæ_. + +[Illustration: FIG. 191.—Palatal aspect of the cranium of _Coryphodon +hamatus_, from the Wasatch Eocene of New Mexico. ²⁄₉ natural size. (After +Cope.)] + + +_Suborder_ CONDYLARTHRA. + +The term Condylarthra has been proposed by Professor Cope for a number +of generalised and mostly comparatively small Ungulates, which were +probably allied both to the Perissodactyla and Artiodactyla, but present +characters separating them from those divisions as commonly defined. In +the structure of the carpus and tarsus these forms (which are chiefly +known to us from the Eocene of the United States) come nearer to the +Hyracoidea than to any other existing type. As a rule they have the full +dental formula; the molars are brachydont, generally bunodont, and in +many instances also tritubercular; while the premolars are always simpler +than the molars. + +The humerus is quite peculiar among Ungulates in having an entepicondylar +foramen; the femur has a third trochanter; and the form and relations of +the astragalus are similar to those obtaining in the Carnivora. The feet +are usually furnished with five functional digits, of which the ungual +phalanges are pointed. In many respects the skeleton of these remarkably +generalised Ungulates approximates so decidedly to a Carnivorous type as +to have led palæontologists to conclude that the Ungulata and Carnivora +are branches of an original common stock. + +In this work space only permits of allusion to a few of the more +important types of this group. _Periptychus_, which occurs in the lowest +Eocene of New Mexico, is a bunodont type readily distinguished by the +vertical flutings of the premolars, and the small size of the incisors +and canines. It has been suggested that this genus is closely related to +the stock of the bunodont Artiodactyla. Of greater interest is the genus +_Phenacodus_, which is regarded as the lowest factor in the series from +which the modern Horse has been evolved, where it holds the position +immediately below _Hyracotherium_ or, _Systemodon_ (see p. 374). One of +the species was about the size of a Bull-dog, while another might be +compared to a small Leopard. The structure of the cheek-teeth is such +as might readily be modified into that obtaining in _Hyracotherium_; +all the feet had five fully developed digits, and the tail was long. +_Meniscotherium_ and _Hyracodontotherium_ are more specialised forms of +somewhat later age, with a lophodont dentition: the latter genus being +European. + + +_Suborder_ TOXODONTIA. + +In addition to the _Macraucheniidæ_ and certain other forms noticed +under the head of the Perissodactyla, the Tertiaries of South America +have yielded some very remarkable forms of mammalian life, the nature +and affinities of which have greatly puzzled all zoologists who have +attempted to unravel them. + +_Nesodon_ and _Toxodon_.—Among these _Nesodon_, from Patagonia, has the +full typical Eutherian number of teeth; the crowns of the incisors being +short, and the molars having a complex rhinocerotic type of structure +somewhat intermediate between _Homalodontotherium_ (p. 412) and the +following genus _Toxodon_. The typical species of _Nesodon_ was about +as large as a Sheep, but nothing more is known of it than the teeth and +portions of the skull. + +_Toxodon_ is an animal about the size of a Hippopotamus; it was first +discovered by Darwin, and many specimens have since been found in +Pleistocene deposits near Buenos Ayres, and described by Owen, Gervais, +and Burmeister. The teeth consist of large incisors, very small lower +canines, and strongly curved molars, all with persistent roots, the +formula being apparently _i_ ²⁄₃, _c_ ⁰⁄₁, _p_ ⁴⁄₃, _m_ ³⁄₃ = 38. +The cranial characters exhibit a combination of those found in both +Perissodactyles and Artiodactyles, but the form of the hinder part of the +palate and the absence of an alisphenoid canal belong to the latter; and +the tympanic, firmly fixed in between the squamosal and the exoccipital, +ankylosed to both, and forming the floor of a long upward-directed meatus +auditorius, is so exactly like that of the Suina that it is difficult +to believe it does not indicate some real affinity to that group. These +characters seem to outweigh in importance those by which some zoologists +have linked _Toxodon_ to the Perissodactyla, and the absence of the third +trochanter and the articulation of the fibula with the calcaneum tell in +the same direction. According to the recent observations of Ameghino the +hind feet were certainly tridactylous, and the front feet probably so. +The earlier allied genera _Protoxodon_ and _Adinotherium_ are definitely +known to have tridactylous front and hind feet, which conform to the +Perissodactylate type, the bones of the proximal and distal rows of the +carpus interlocking. _Acrotherium_, which has similar feet, differs +from all other Ungulates, and indeed from all Eutherians except some +individuals of the existing carnivorous genus _Otocyon_, in having eight +cheek-teeth, five of which have been reckoned as premolars. + +[Illustration: FIG. 192.—Cranium and Lower Jaw of _Typotherium +cristatum_. ¹⁄₃ natural size. From Gervais.] + +_Typotherium._—_Typotherium_ (Fig. 192), also called _Mesotherium_, +from the same locality as _Toxodon_, was an animal rather larger than +a Capybara, and of much the same general appearance. Its skeleton is +completely known, and shows a singular combination of characters, +resembling _Toxodon_ or a generalised Ungulate on the one hand, and the +Rodents, especially the _Leporidæ_, on the other. In the presence of +clavicles it differs from all known Ungulates, and in having two pairs of +lower incisors from all Rodents. The teeth are _i_ ¹⁄₂, _c_ ⁰⁄₀, _p_ ²⁄₁, +_m_ ³⁄₃ = 24. + +From the Tertiaries of various parts of South America a number of forms +more or less closely allied to _Toxodon_ and _Typotherium_ have been +recently described, but as many of them are very imperfectly known, and +there is much doubt as to their generic position, it will be unnecessary +to refer to them further. + +It will thus be seen that, although our knowledge of many of these +forms is still very limited, we may trace among them a curious chain of +affinities, which would seem to unite the Ungulates on the one hand with +the Rodents on the other; but further materials are required before we +can establish with certainty so important a relationship, one which, +if true, would alter materially some of the prevailing views upon the +classification of mammals. + + +_Group_ TILLODONTIA. + +[Illustration: FIG. 193.—Skull of _Tillotherium fodiens_. ⅙ natural size. +From Marsh.] + +Here may be noticed a remarkable group of animals, called by Marsh, +Tillodontia, the remains of which are found abundantly in the Lower and +Middle Eocene beds of North America. They seem to combine the characters +of the Ungulata, Rodentia, and Carnivora. In the genus _Tillotherium_ of +Marsh (probably identical with the previously described _Anchippodus_ of +Leidy) the skull (Fig. 193) resembled that of the Bears, but the molar +teeth were of the Ungulate type, while the large incisors were very +similar to those of the Rodents. The dental formula is _i_ ²⁄₂, _c_ ¹⁄₁, +_p_ ³⁄₄, _m_ ³⁄₃. The first pair of incisors was very small; the upper +molars were tritubercular, while the lower ones had crescentoid ridges as +in _Palæotherium_. The skeleton resembled that of the Carnivores, but the +scaphoid and lunar bones were distinct, and there was a third trochanter +on the femur. The feet were plantigrade, and each had five digits, all +with long pointed claws. In the allied genus _Stylinodon_ all the teeth +were rootless. Some forms were as large as a Tapir. + +These, with other more or less closely allied animals, such as +_Calamodon_ and _Psittacotherium_, constituting a group called +Tæniodonta, are included by Cope in his large order Bunotheria, to which +also the existing Insectivora are referred. The dentition of some of +these forms makes a remarkable approximation towards a Rodent type, +while it has been suggested that there are also signs of remote Edentate +affinities. The constantly increasing knowledge of these annectant forms +adds to the difficulty so often referred to in this work of establishing +anything like a definite classification of the heterodont mammals. +An incisor tooth from the Swiss Eocene has recently been referred to +_Calamodon_. + + _Bibliography of Ungulata._—In addition to the works and + memoirs mentioned under the different sections of the order, + the following may be referred to:—W. Kowalevsky, “Monographie + des genus Anthracotherium,” _Palæontographica_ 1873; Id. “Sur + l’Anchitherium aurelianense et sur l’histoire paléontologique + des Chevaux,” _Mém. de l’Acad. Imp. des Sciences de St. + Pétersbourg_, 1873; Id. “On the Osteology of the Hyopotamidæ,” + _Philosophical Transactions_, 1873; L. Rütimeyer, “Versuch + einer natürlichen Geschichte des Rindes.” etc., _Neue Denks. + der allgem. Schweiz. Gesellsch. für Naturwissenschaften_, 1867; + Id. “Die Rinder der Tertiär-Epoche,” _Abhand. der Schweiz. + Paläont. Gesellsch._ 1877 and 1878; Id. “Beiträge zu einer + Natürliche Geschichte der Hirsche,” _ibid._ 1880-1881; C. J. + Forsyth-Major, “Beiträge zur Geschichte der Fossilen Pferde,” + _ibid._ 1880; M. Schlosser, “Beiträge zur Kenntniss der + Stammesgeschichte der Hufthiere und Versuch einer Systematik + der Paar- und Unpaarhufer,” _Morph. Jahrb._ 1886; E. D. Cope, + “The Perissodactyla,” _Amer. Natural._ 1887; M. Pavlow, “Études + sur l’histoire paléontologique des Ongulés,” _Bull. Soc. Imp. + Naturalistes Moscow_, 1887-1890. W. B. Scott and H. F. Osborn, + “The Mammalia of the Uinta Formation,” _Trans. Amer. Phil. + Soc._ vol. xvi. (1889). + + + + +CHAPTER X + +THE ORDER RODENTIA + + +The Rodentia, or Rodents, form a well-defined order, readily +distinguished by their large scalpriform incisors and the absence of +any trace of canines. The existing forms are mostly of comparatively +small size, and are generally of terrestrial habits, although a few are +arboreal or natatorial. The dentition is diphyodont; the mandible never +has more than a single pair of incisors; the premolars are always below +the full number, being very generally ¹⁄₁, or altogether wanting. The +feet are plantigrade or semi-plantigrade, generally with five digits, +and usually unguiculate, although occasionally of a subungulate type. +Clavicles are present as a rule, although they may be imperfect or +rudimentary. + +The upper incisors resemble the lower in growing uninterruptedly from +persistent pulps, and, except in the suborder Duplicidentata, agree with +them in number; the premolars and molars may be rooted or rootless, with +tuberculated or laminated crowns, and are arranged in an unbroken series. +The orbits communicate freely with the temporal fossæ; the condyle of the +mandible is elongated in the antero-posterior direction, and, through the +absence of a post-glenoid process to the squamosal, admits of a backward +and forward motion of the jaw. The intestine (except in the _Myoxidæ_) +has a large cæcum; the testes are inguinal or abdominal; the uterus is +two-horned, the cornua either opening separately into the vagina or +uniting to form a corpus uteri; the placenta is discoidal and deciduate; +and the smooth cerebral hemispheres do not extend backwards so as to +cover any part of the cerebellum. + +[Illustration: FIG. 194.—Skull of _Hystrix cristata_ (juv.) _t_, Temporal +muscle; _m_, masseter; _m′_, portion of masseter transmitted through +the infraorbital foramen, the superior maxillary nerve passing outwards +between it and the maxillary bone.] + +The Rodents include by far the greatest number of species, and have the +widest distribution of any of the orders of terrestrial mammals, being in +fact cosmopolitan, although more abundant in some parts than in others. +The total number of known existing species exceeds 900. South America may +be regarded as their headquarters at the present day; while in Australia +and Madagascar they are represented only by a few genera. All the Rodents +are exclusively herbivorous, and the whole of them gather their food +by gnawing. They present considerable diversity of habits. Thus the +Squirrels are arboreal, and some of them provided with a parachute for +taking flying leaps from tree to tree; the Hares are cursorial; the +Jerboas agile jumpers; the Mole-Rats fossorial; while the Beavers and +Water-Voles are aquatic. In spite, however, of this diversity of habits +the Rodents present a remarkable similarity in general structure; so +much so, indeed, that the characters employed for distinguishing the +various families and genera are comparatively trivial, and of slight +structural importance. The skull of the Rodents is characterised by the +invariable presence of the zygomatic arch, of which the middle portion +is formed by the jugal (Fig. 7, p. 37); and, as already mentioned, the +orbit communicates freely with the temporal fossa. There is invariably +a long diastema separating the incisors from the cheek-teeth; and, with +the exception of the Duplicidentata, the glenoid cavity of the squamosal +is elongated antero-posteriorly. Postorbital processes of the frontals +exist only in the Squirrels, Marmots, and Hares; in all other genera they +are rudimentary or altogether absent; the zygoma never sends upwards a +corresponding process; the lachrymal foramen is always within the orbital +margin; in many species the infraorbital foramen is very large (in some +as large as the orbit), and transmits part of the great masseter muscle +(Fig. 194, _m_), by means of which the jaws are worked. The zygomatic +arch varies in its degree of development, and the position of the jugal +therein is used as a distinguishing character for grouping the families; +the nasals are, with few exceptions, large, and extend far forwards; the +parietals are moderate, and there is generally a distinct interparietal. +The palate is narrow from before backwards—this being especially +pronounced in the Hares, where it is reduced to a mere bridge between the +premolars; while in other cases, as in the Mole-Rats (_Bathyerginæ_), it +is extremely narrow transversely, its width being less than that of one +of the molar teeth. Auditory bullæ are always present, and generally +large; in some genera, as in the Gerbilles and Jerboas, there are also +supplemental mastoid bullæ forming great hemispherical bony swellings at +the back of the skull (see Fig. 7, _Per_); and in these genera, and in +the true Hares, the meatus auditorius is tubular and directed upwards +and backwards. The mandible is characterised by the abruptly narrowed +and rounded symphysial part supporting the large incisors, as well as by +the small size of the coronoid process and the great development of the +angular portion. + +The dental formula varies from _i_ ²⁄₁, _c_ ⁰⁄₀, _p_ ³⁄₂, _m_ ³⁄₃ (total +28) in the Duplicidentata to _i_ ¹⁄₁, _c_ ⁰⁄₀, _p_ ⁰⁄₀, _m_ ²⁄₂ (total +12) in _Hydromys_, _Xeromys_, and one species of _Heterocephalus_; but +in the great majority of forms it is very constant, _i_ ¹⁄₁, _c_ ⁰⁄₀, +_p_ ⁰⁻¹⁄₀₋₁, _m_ ³⁄₃ being very typical. Only in the Duplicidentata is +there a second pair of upper incisors, which are of very small size, and +situated immediately behind the large normal pair. This group is also +peculiar in that the enamel of the incisors is not confined to their +anterior surfaces, but extends partially on to their sides. It is by +reason of the thick layer of enamel on their anterior surface and its +absence from the posterior surface that the incisors maintain their +sharp chisel-like edge, which is so essentially characteristic of the +order. Both the upper and the lower incisors are regularly curved—the +curvature being somewhat greater in the upper ones—and since they grew +continuously from persistent pulps, it is quite evident that should any +accident, such as the loss of one of them, or displacement by fracture +of the jaw, prevent the regulation of the length by attrition against +one another, the unopposed tooth will gradually curve upon itself until +a complete circle or more has been formed, the tooth, perhaps, passing +during its growth through some part of the animal’s head. The molars, as +already mentioned, may be rooted or rootless, tuberculated or laminated; +this diversity of structure occurring even in the same family. When there +are more than three cheek-teeth those in front of the last three have +succeeded milk-teeth, and must therefore be considered premolars. In some +species, as in the Agoutis (_Dasyproctidæ_), the milk-teeth are long +retained, while in the allied Cavies (_Caviidæ_) they are shed before +birth. + +[Illustration: FIG. 195.—Vertical and longitudinal section through +skull of the Beaver (_Castor fiber_) showing the cerebral cavity, the +greatly developed turbinal lamellæ, the mode of implantation of the large +incisor, and the curved, rootless molars.] + +There are generally nineteen dorso-lumbar vertebræ (thirteen dorsal and +six lumbar), their form varying in the different genera. In the cursorial +and leaping species the lumbar transverse processes are generally +very long, and in the Hares there are large compressed hypapophyses. +The caudal vertebræ exhibit great variety in structure, being in a +rudimentary condition in the Guinea-Pig, while in the Jumping Hares +and prehensile-tailed Porcupines they are of very large dimensions. +The scapula is usually narrow, with a long acromion; the clavicles may +be altogether absent or imperfect, as in the Porcupines, Cavies, and +Hares, but in most species they are well developed. In all existing +forms the humerus has no entepicondylar foramen, and the radius and +ulna are distinct. In most species the manus has five digits, with +phalanges normally developed; the pollex being rarely rudimentary or +absent. The pelvis has well-developed ischia and pubes, meeting in a +long, and usually bony, symphysis. The femur varies considerably in form, +but generally has a well-defined third trochanter; in the Sciurine and +Hystricine Rodents the tibia and fibula are distinct, but in the Rats +and other Murines, and in the Hares, these bones are united, often high +up; the pes is much more variable than the manus, the digits varying +in number from five, as in the Squirrels and Rats, to four, as in the +Hares, or even three, as in the Capybara, Viscacha, and Agouti; in the +_Dipodidæ_ the metatarsals are greatly elongated, and in some of the +species, as in the Jerboas, they are ankylosed together. + +The mouth is divided into two cavities communicating by a constricted +orifice, an anterior one containing the large incisors, and a posterior +one in which the molars are placed; the hairy integument of the face +being continued inwards behind the incisors. This peculiar arrangement +evidently prevents substances not intended for food getting into the +mouth, as when the animal is engaged in gnawing through an obstacle. +In the Hares and Pacas the inside of the cheeks is hairy, and in some +species, as in the Pouched Rats and Hamsters, there are large internal +cheek-pouches lined with the hairy integument, which open near the angles +of the mouth and extend backwards behind the ears. In the New World +Pouched Rats (_Geomyidæ_) the pouches open externally on the cheeks. The +tongue presents little variability in length, being always short and +compressed, with an obtuse apex never protruded beyond the incisors. In +most species there are three circumvallate papillæ at the base; and the +apical portion is generally covered with small filiform papillæ, some +of which in the Porcupines (_Hystrix_) become greatly enlarged, forming +toothed spines. The stomach varies in form from the simple oval sac of +the Squirrel to the complex ruminant-like organ of the Lemming. In the +Water-Vole (_Arvicola amphibius_) and the Agouti (_Dasyprocta aguti_) +it is strongly constricted between the œsophagus and pylorus. In the +common Dormouse the œsophagus immediately before entering the stomach is +much dilated, forming a large egg-shaped sac with thickened glandular +walls; and in some other species, as in _Lophiomys imhausi_ and in the +Beaver, glandular masses are attached to and open into the cardiac or +pyloric pouches. The alimentary canal (Fig. 196) of all Rodents, with +the exception of the Dormice (_Myoxidæ_), has a cæcum, which is often +of great length and sacculated, as in the Hares, Water-Voles, and +Porcupines. In some instances, as in the Hamster and Water-Vole, the long +colon is spirally twisted upon itself near its commencement. The liver is +typically divided in all, but the lobes are variously subdivided in the +different species (in _Capromys_ they are divided into minute lobules); +and the gall-bladder, though present in most, is absent in a few. In most +species the penis (which is generally provided with a bone) can be more +or less completely retracted within the fold of integument surrounding +the anus, where it lies curved backwards upon itself under cover of the +integument. It may, however, be carried forward some distance in front +of the anal orifice, from which in the breeding season, as in the Voles +and Marmots, the prominent testicular mass separates it. The testes +in the rutting season form projections in the groins, but (except in +the Duplicidentata) do not completely leave the cavity of the abdomen. +Prostatic glands and, except in the Duplicidentata, vesiculæ seminales +are present in all. The uterus may be double, each division opening by +a separate aperture into a common vagina, as in _Leporidæ_, _Sciuridæ_, +and _Hydrochœrus_, or completely two-horned, as in most species. The +mammæ vary in number and position from the single abdominal pair of the +Guinea-Pig to the ten thoracico-abdominal pairs found in some of the +Rats. In the _Octodontidæ_ the mammæ are placed high up on the sides of +the body. + +[Illustration: FIG. 196.—Alimentary canal of Rat (_Mus decumanus_), the +greater part of the small intestine being omitted. _o_, Œsophagus; _d_, +duodenum; _i_, ileum; _cm_, cæcum; _c_, colon.] + +The peculiar odour evolved by many Rodents is due to the secretions of +special glands, which may open either into the prepuce, as in _Mus_, +_Arvicola_, _Cricetus_, etc., or into the rectum, as in _Arctomys_ and +_Aulacodus_ or into the passage common to both, as in the Beaver, or +again, into pouches opening near the anus, as in the Hare, Agouti, and +Jerboa. + +The integument is generally thin, and the panniculus carnosus (the sheet +of muscle underlying the skin) rarely much developed. The fur varies +exceedingly in character. Thus it may be very fine and soft, as in the +Chinchillas and Hares, in others more or less replaced by spines on the +upper surface, as in the Spiny-Rats and Porcupines; in several genera, as +in _Xerus_, _Acanthomys_, _Platacanthomys_, _Echinothrix_, _Loncheres_, +and _Echinomys_, the spines are flattened. In the muscular structures +the chief peculiarities are noticeable in the comparatively small size +of the temporal muscles, and in the great double masseters (Fig. 194), +which are the principal agents in gnawing; the digastrics also are +remarkable for their well-defined central tendon, and in many species +their anterior bellies are united between the mandibular rami; the +cleidomastoid generally arises from the basioccipital, and the pectoralis +major is connected with the latissimus dorsi; in the Porcupines and Hares +the tendons of the flexor digitorum longus and flexor hallucis longus are +connected in the foot, while in the Rats and Squirrels they are separate, +and the flexor digitorum longus is generally inserted into the metatarsal +of the hallux.[290] + +Rodents are tolerably well represented in a fossil condition from the +period of the Upper Eocene, while if _Decticadapis_, of the Lower Eocene +of Rheims, is rightly referred to it the order dates from the oldest +Tertiary. All the fossil forms at present known are, however, essentially +true Rodents, and afford no clue as to the relations of the order with +other mammals. The remote affinities of the Rodents to the Proboscidea, +as well as their more marked resemblances to _Typotherium_, have been +already mentioned. Whether there is a real genetic affinity (as Professor +Cope suggests) with the Tillodontia cannot be decided with the evidence +at present available. + + +_Suborder_ SIMPLICIDENTATA. + +Only one pair of upper incisors, having their enamel confined to their +front surfaces. Incisive foramina moderate and distinct; fibula not +articulating with the calcaneum. Testes abdominal, and descending +periodically only into a temporary sessile scrotum. + + +_Section_ SCIUROMORPHA. + +Zygomatic arch slender, chiefly formed by the jugal, which is not +supported by a long maxillary process extending backwards beneath it; +postorbital processes of frontal present or absent; infraorbital opening +small (except in _Anomalurus_); mandible with the angular part arising +from the inferior surface of the bony socket of the lower incisor; +clavicles well developed; fibula distinct. + + +_Family_ ANOMALURIDÆ. + +Arboreal forms, having their limbs connected by a cutaneous expansion +supported by a cartilaginous process arising from the olecranon; tail +long and hairy, with large imbricated scales on its inferior surface +near the root; sixteen pairs of ribs; no postorbital processes on the +frontals; _p_ ¹⁄₁; molars not tuberculate, with transverse enamel-folds. +Confined to the Ethiopian region. + +[Illustration: FIG. 197.—_Anomalurus fulgens._ From Alston, _Proc. Zool. +Soc._ 1875.] + +_Anomalurus_,[291] with several species from West and Central Africa, +alone represents the family. The peculiar caudal scales, which evidently +assist the animal in climbing, and the position of the cartilaginous +support of the parachute, are well shown in Fig. 197. All the species +but two are from Western Africa; _A. orientalis_ occurs near Zanzibar, +and _A. pusillus_ is from the equatorial regions of that continent. +According to Mr. O. Thomas,[292] the latter “little animal is most nearly +allied to the West-African _A. beecrofti_, but differs from that species +in its duller and less yellow upper side, in the entire absence of rufous +on its neck and belly, and, as from all the other described species, in +its diminutive size.” + + +_Family_ SCIURIDÆ. + +Arboreal or terrestrial forms, with cylindrical hairy tails, without +scales, and with twelve or thirteen pairs of ribs. Skull (Figs. 198, 199) +with distinct postorbital processes; infraorbital opening small; palate +broad; _p_ ²⁄₁; first upper premolar very small or deciduous; molars +rooted, tubercular. + +Subfamily =Sciurinæ=.—Incisors compressed; form slender; tail long and +hairy. Cosmopolitan (excluding Australian region). + +[Illustration: FIG. 198.—Lateral view of skull of American Marmot +(_Arctomys monax_).] + +This subfamily includes the true Squirrels, of which seven existing +genera are usually recognised. + +_Sciurus._[293]—Tail long and bushy; ears generally well developed, +pointed, often tufted; feet adapted for climbing, the anterior having +four digits and a rudimentary pollex, and the posterior with five digits, +all of which have long, curved, and sharp claws. Mammæ, from four to +six. Skull (Fig. 199) lightly built, with long postorbital processes. +Penultimate upper premolar, when present, minute. + +[Illustration: FIG. 199.—Palatal Aspect of cranium of Squirrel (_Sciurus +bicolor_). Natural size.] + +True Squirrels are found in most of the temperate and tropical regions of +the world, exclusive of Madagascar and the Australian region. They are, +however, most abundant in the Malayan part of the Oriental region, and +attain their largest size and most brilliant coloration in the tropics. +Their size is very variable, so that whereas _S. soricinus_, of Borneo, +is no larger than a Mouse, _S. bicolor_, of the Malayan region, is nearly +as large as a Cat. The common English Squirrel (_S. vulgaris_) is found +over the whole of the Palæarctic region, reaching in one direction from +Ireland to Japan, and in the other from the north of Italy to Lapland; +its remains occur in the Norfolk “Forest-bed.” In the Malayan region +“nearly all the numerous species are brilliantly marked, and many are +ornamented with variously coloured longitudinal stripes along their +bodies. One of the commonest and best known of the striped species is +the little Indian Palm-Squirrel (_S. palmarum_), which in large numbers +runs about every Indian village. Another Oriental species (_S. caniceps_) +presents almost the only known instance among mammals of the temporary +assumption during the breeding season of a distinctly ornamental coat, +corresponding to the breeding-plumage of birds. For the greater part of +the year the animal is of a uniform gray colour; but about December its +back becomes a brilliant orange-yellow, which lasts until about March, +when it is again replaced by gray. The Squirrel shown in Fig. 200 is a +native of Burma and Tenasserim, and is closely allied to _S. caniceps_, +but goes through no seasonal change of colour. + +[Illustration: FIG. 200.—Burmese Squirrel (_Sciurus pygerythrus_). After +Anderson.] + +“The number of species in the genus is about 75, of which 3 belong to the +Palæarctic, 15 to the Ethiopian, about 40 to the Oriental, and 16 to the +combined Nearctic and Neotropical regions” (Thomas). + +Fossil species referred to _Sciurus_ are found in the European Tertiaries +down to the Phosphorites of Central France, while others occur in the +White River Miocene of the United States. + +_Rhithrosciurus._[294]—A very striking Squirrel, confined to Borneo, +and as yet only known from three or four examples, has been separated +generically under this name. The general shape of its skull is +very different from that of other Squirrels; but its most peculiar +characteristic is the presence of from seven to ten minute parallel +vertical grooves running down the front face of its incisors; no other +Squirrel having really grooved incisors, and no other member of the +whole order incisive grooves resembling these. Its premolars number ¹⁄₁, +and its molars are simpler and less ridged than in the other genera. +This Squirrel (_R. macrotis_) is far larger than the English, with an +enormously long bushy tail, long tufted ears, and black and white bands +down its sides. + +_Xerus._[295]—Fur coarse and spiny. Claws long and comparatively +straight. Ear-conchs minute or absent. Skull with the postorbital +processes short and directed backwards, the bony palate prolonged +considerably behind the tooth-row, and the external ridge on the front +face of the anterior zygomatic root more developed, and continued much +farther upwards than in _Sciurus_. Premolars ²⁄₁; molars as in _Sciurus_. +Mammæ two. This genus contains four well-marked species, known as Spiny +Squirrels, all natives of Africa. They are terrestrial in their habits, +living in burrows which they dig for themselves. _X. getulus_, a striped +species of North Africa, has much the size and appearance of the Indian +Palm-Squirrel; all the others are a little larger than the English +Squirrel. + +_Tamias._[296]—All the members of this genus are characterised by the +possession of internal cheek-pouches, and by their style of coloration; +being ornamented on the back with alternate light and dark bands. Their +skulls are slenderer and lighter than those of the true Squirrels, from +which they differ in several unimportant details. There is only one +functional premolar—the small anterior one usually found in _Sciurus_ +being either absent altogether or quite small and functionless. There +are some four well-defined species, all found in North America, one (_T. +asiaticus_) extending also through Siberia into Eastern Europe.[297] +They are generally known as Ground-Squirrels, but in America, where +they are among the commonest and best known of the indigenous Rodents, +as “Chipmunks.” The members of this genus seem to lead into the genus +_Spermophilus_, so that the division of the _Sciuridæ_ into two +subfamilies, although convenient for classification, is rather artificial. + +Remains of _Tamias_, probably belonging to existing species, occur in the +Pleistocene deposits of Europe and Nebraska. + +_Pteromys_[298] and _Sciuropterus_.[299]—The Flying Squirrels, although +incapable of true flight, can yet float through the air for considerable +distances by the aid of an extension of skin connecting their fore and +hind limbs, and forming a sort of parachute. This parachute is merely a +lateral extension of the ordinary skin of the body, which passes outwards +between the limbs and terminates at the wrists and ankles. In addition +to the lateral membrane there is a narrow and inconspicuous one passing +from the cheek along the front of the shoulder to the front of the wrist, +and another—at least in the larger species—stretching across behind the +body from ankle to ankle and involving the base of the tail. The Flying +Squirrels are divided into three genera. Of those with a normal dentition +_Pteromys_ contains the larger and _Sciuropterus_ the smaller species. +The two differ in certain details of dentition, as well as in the greater +development in the former of the expanded membranes, especially of the +“interfemoral” or posterior membrane, which in the latter is almost +wholly absent. In _Pteromys_ the tail is cylindrical and comparatively +thin, while in _Sciuropterus_ it is broad, flat, and laterally expanded, +and evidently compensates for the absence of the interfemoral membrane +by acting as a supplementary parachute. In appearance Flying Squirrels +resemble the other forms, although they are even more beautifully +coloured. Their habits, food, etc., are also very similar to those of the +true Squirrels, except that they are more decidedly nocturnal, and are +therefore less often seen by the traveller; their peculiar shrill cry +is, however, well known to all who have camped out in the regions which +they inhabit. Their mode of flight is precisely similar to that of the +Flying Phalangers of Australia. Of each of the two genera there are about +thirteen or fourteen species, all natives of the Oriental region, except +that one of _Sciuropterus_ is found in North America, and another in +Siberia and Eastern Europe. + +_Eupetaurus._[300]—Externally as in _Pteromys_, except that the claws +are less sharp. Skull with a more produced muzzle than in the latter, +more distinct supraorbital notches, longer anterior palatal foramina, +and a shorter bony palate. Cheek-teeth differing from those of all +other _Sciuridæ_ in their hypsodont character. One large species (_E. +cinereus_), from Gilgit and adjacent districts on the extreme north-west +of Kashmir territory. This fine Flying Squirrel is chiefly known by one +entire specimen and some imperfect skins. + +_Extinct Genera._—The genera _Pseudosciurus_ and _Sciuroides_, from the +Upper Eocene of Europe, have the molar teeth more elongated than in +_Sciurus_. _Gymnoptychus_ with _p_ ¹⁄₁, from the North American Miocene, +approximates in the structure of its molars to _Tamias_. _Meniscomys_ +(_p_ ²⁄₁), from the latter deposits, together with _Sciurodon_ of the +French Phosphorites, are regarded as Squirrels showing signs of affinity +with the _Haplodontidæ_. + +Subfamily =Arctomyinæ=.—Incisors not compressed; typically the form +stout, and the tail comparatively short. This subfamily comprises +burrowing forms which may be collectively known as Marmots; as already +mentioned, they are so intimately connected with the preceding subfamily +that the division into two groups is purely a matter of convenience. They +are confined to the Palæarctic and Nearctic regions. + +_Arctomys._[301]—External form stout and heavy, ears short, tail short +and hairy, cheek-pouches rudimentary or absent. Fore feet with four +well-developed digits, and a rudimentary pollex provided with a flat +nail. Skull (Fig. 198) large and heavy, with the postorbital process +stout, and at right angles to the axis. Incisors broad and powerful. +First upper premolar nearly as large as the second. Molar series nearly +parallel, scarcely converging behind at all. + +The various species of true Marmot, which exceed a dozen in number, are +all much alike in general appearance, ranging in size from about 15 to 25 +inches in length, with tails from 3 to 12 inches long. + +The Alpine Marmot (Fig. 201) is peculiar to Europe, being found in +the Alps, Pyrenees, and Carpathians; its remains occur in European +Pleistocene deposits. _A. bobac_ occurs in Eastern Europe and Siberia. +Several species (_e.g._ _A. monax_, Fig. 198) are found in the Nearctic +region, and many in Kashmir and Central Asia. The long-tailed Red Marmot +(_A. caudatus_) is a fine Himalayan species, which may be seen on the +mountain passes to the north of the valley of Kashmir, as soon as the +snow begins to disappear, sitting at the entrance to its burrow, which is +generally beneath a rhubarb plant. + +[Illustration: FIG. 201.—Alpine Marmot (_Arctomys marmotta_). After +Brehm.] + +The following account of the habits of the Alpine Marmot is given by +Professor Blasius: “Marmots live high up in the snowy regions of the +mountains, generally preferring exposed cliffs, whence they may have a +clear view of any approaching danger, for which, while quietly basking +in the sun or actively running about in search of food, a constant watch +is kept. When one of them raises the cry of warning, the loud piercing +whistle so well known to travellers in the Alps, they all instantly take +to flight and hide themselves in holes and crannies among the rocks, +often not reappearing at the entrance of their hiding-places until +several hours have elapsed, and then frequently standing motionless on +the look-out for a still longer period. Their food consists of the roots +and leaves of various Alpine plants, which, like squirrels, they lift to +their mouths with their fore paws. For their winter quarters they make a +large round burrow, with but one entrance, and ending in a sleeping-place +thickly lined with hay. Here often from ten to fifteen Marmots pass the +winter, all lying closely packed together fast asleep until the spring.” + +_Cynomys._[302]—Size and form intermediate between _Arctomys_ and +_Spermophilus_. Ears and tail short. Cheek-pouches shallow. Fore feet +with five claws, that on the pollex as large as that on the fifth toe. +Skull (Fig. 202) heavily built, with the postorbital processes directed +outwards. Dentition (as shown in Fig. 202) remarkably heavy, the molar +teeth differing from those of _Arctomys_ and _Spermophilus_ by having +three instead of two transverse grooves on their crowns. First premolar +nearly as large as the second. Molar series strongly convergent behind. + +Two species of Prairie Marmots, or, as they are often called, +“Prairie-Dogs,” are found in North America. They live together in large +communities, inhabiting burrows excavated at short distances apart, and +feeding on the buffalo-grass which covers the plains. The small burrowing +owl (_Athene cunicularia_) and the rattlesnake are often found inhabiting +their burrows; the former probably availing itself of the convenience of +a ready-made habitation, the latter coming there to feed on the young +Marmots. + +[Illustration: FIG. 202.—Palatal aspect of the cranium of the Prairie +Marmot (_Cynomys ludovicianus_).] + +_Spermophilus._[303]—Size much smaller than in either of the preceding +genera; form more slender and squirrel-like. Tail very variable, from 1 +to 8 or 9 inches in length. Cheek-pouches always present. Fore feet with +four well-developed toes and a rudimentary pollex, of which the claw may +be either present or absent. Skull more lightly built than in the other +preceding genera, with the postorbital processes slender and directed +backwards. Molar series nearly parallel, as in _Arctomys_, but all these +teeth much smaller and lighter; first premolar simply rounded, never more +than about one-third of the size of the second. + +The Pouched Marmots, or Sousliks, have nearly the same distribution as +_Tamias_, and are represented by a considerable number of species. They +present a far greater range of variation than is found among the true +Marmots, some of them, such as the European species, being scarcely +as large as a common squirrel, almost entirely without external ears, +and with the tail reduced to a mere stump, barely an inch long, while +others are more than three times this size, with large and often tufted +ears, and long bushy squirrel-like tails. Professor Blasius gives the +following details of the habits of the common European Souslik (_S. +citillus_): “It lives in dry treeless plains, especially on a sandy or +clayey soil, and is never found either in forests or on swampy ground. +It forms burrows, often 6 or 8 feet deep, in which food is stored up +and the winter sleep takes place. Each burrow has but one entrance, +which is closed up when winter approaches,—a second hole, however, being +previously formed from the sleeping-place to just below the surface of +the ground. The second hole is opened the next year, and used as the +ordinary entrance, so that the number of closed-up holes round a burrow +gives an indication of the length of time that it has been occupied. +Sousliks ordinarily feed on roots, seeds, berries, etc., but occasionally +also on animal food, preying readily on eggs, small birds, and mice, +the remains of these latter being often found in their burrows. They +bring forth in the spring from four to eight young ones, which, if taken +early, may be easily tamed. They are often eaten by the peasants, the +inhabitants of the Russian steppes considering their flesh an especial +delicacy.” + +Remains of _Spermophilus_ are not uncommon in European Tertiary deposits, +some belonging to living and others to extinct species. + +_Extinct Genera._—_Plesispermophilus_, from the Upper Eocene Phosphorites +of Central France, appears to be closely allied to the Sousliks. +_Plesiarctomys_ (_Sciuravus_ or _Paramys_), which is common to the Middle +Tertiaries of Europe and North America, appears to be a generalised form, +showing some resemblance both to _Arctomys_ and _Sciurus_, but with +tritubercular upper molars and no postorbital processes to the skull; +in the latter respect agreeing with the next family. In the size of the +preorbital vacuity the skull resembles the Hystricomorpha. + + +_Family_ HAPLODONTIDÆ. + +Distinguished from the _Sciuridæ_ by the absence of postorbital processes +to the frontals, the depressed skull, and the rootless cheek-teeth. +Premolars ²⁄₁; the penultimate upper one small. + +_Haplodon._[304]—_H. rufus_ and _H. major_, of North America, west of the +Rocky Mountains, are the only representatives of the family; their habits +are similar to those of _Cynomys_. + + +_Family_ CASTORIDÆ. + +Skull massive, without postorbital processes, the angle of the mandible +rounded, and the cheek-teeth rootless, with re-entering enamel-folds. +Premolars ¹⁄₁. Habits natatorial. + +_Castor._[305]—The upper molars are subequal, each with one internal +and two external enamel-folds; the stomach has a large glandular +mass situated to the right of the œsophageal orifice; the anal and +urethro-genital orifices open within a common cloaca; the tail is broad, +horizontally flattened, and naked; and the hind feet are webbed. One or +two species, Palæarctic and Nearctic. + +Zoologists are not yet of accord as to whether the European and American +Beavers should be regarded as distinct species or as local races; the +general concensus of opinion being in favour of the latter view. + +The European Beaver (_C. fiber_) was at one time an inhabitant of the +British Isles, having been found, according to Pennant, in certain Welsh +rivers so late as the twelfth century, while subfossil remains of it +occur in the peat-beds of many parts of the country. In Scandinavia +Beavers are still found in the neighbourhood of Arendal. Isolated pairs +are occasionally met with on the banks of the Rhone, Weser, and Elbe; +and a considerable number are kept in a park belonging to the Emperor +of Austria, on the banks of the Danube. They also occur sparingly in +Russia and Poland, in the streams of the Ural Mountains, and in those +which flow into the Caspian. They live in burrows on the banks of rivers, +like the Water-Rat, and show little of the architectural instinct so +conspicuous in the American form, but this may be owing to unfavourable +external conditions rather than to want of the faculty; for there is a +well-authenticated instance of a colony of Beavers, on a small stream +near Magdeburg, whose habitations and dam were exactly similar to those +found in America. + +The American Beaver (_C. canadensis_) extends over that part of the +American continent included between the Arctic circle and the tropic of +Cancer; owing, however, to the gradual spread of population over part of +this area, and still more to the enormous quantity of skins that, towards +the end of last and the beginning of the present century, were exported +to Europe, numbering about 200,000 annually, this species is in imminent +danger of extirpation. It is distinguished from the European Beaver by +the shorter and somewhat wider nasals. + +Remains of extinct species of _Castor_ occur in the Pliocene of Europe, +and in the North American Miocene; the one from the last-mentioned +deposits being of small size, and separated by some writers as _Eucastor_. + +_Extinct Genera._—A very large Beaver known as _Trogontherium_ +(_Diobroticus_), and distinguished by the nature of the enamel-folds +of the molars, occurs in the Upper Pliocene and Pleistocene of Europe. +_Chalicomys_ (_Steneofiber_) is a considerably smaller form from the +Miocene of Europe and the United States, distinguished from all existing +Rodents by the presence of an entepicondylar foramen in the humerus. +_Palæocastor_, of the North American Miocene, is allied. + + +_Section_ MYOMORPHA. + +[Illustration: FIG. 203.—Side view of skull of _Fiber zibethicus_, +natural size.] + +Skull (Fig. 203), with slender zygomatic arch, in which the jugal seldom +extends far forwards, being usually supported by the long zygomatic +process of the maxilla; no postorbital process; infraorbital vacuity +variable; angle of mandible, except in the _Bathyerginæ_, rising from +the inferior surface of the incisive alveolus. Clavicles well developed, +except in _Lophiomys_. Tibia and fibula united. + + +_Family_ MYOXIDÆ. + +Small arboreal forms, with long hairy tails, large eyes and ears, and +short fore limbs. No cæcum in the intestine. Skull with narrow frontals, +a high and narrow infraorbital vacuity of moderate size, and a long and +slender coronoid process to the mandible. Premolars ¹⁄₁; molars rooted, +with transverse enamel-folds. + +The Dormice form a natural family allied to the Squirrels in form and +habits, and confined to the Palæarctic and Ethiopian regions. The absence +of the cæcum distinguishes them from all other members of the order. +They are usually divided into the following five genera, but some of +these are of very doubtful value, and it might be preferable to retain +_Muscardinus_ and include all the others in _Myoxus_.[306] + +_Myoxus._[307]—Represented by the European _M. glis_, and characterised +by the bushy distichous tail, simple stomach, and the large size and +complex enamel-folds of the molars, which have flat crowns. + +_Eliomys._[308]—Tail tufted and distichous; stomach simple; and the +molars small, with concave crowns and indistinct enamel-folds. Some seven +species, Ethiopian and Palæarctic. + +_Graphiurus._[309]—Tail short, cylindrical, and tufted at the end; molars +very small, with the enamel-folds almost absent. Some three Ethiopian +species. + +_Claviglis._[310]—Represented by one West African species, said to be +distinguished from all other forms by the shorter tail, which is more +distinctly pencilled. The right to generic distinction is, however, very +problematical. + +_Muscardinus._[311]—Includes the Common Dormouse (_M. avellanarius_) +of Europe, distinguished by the cylindrical bushy tail, and thickened +glandular walls of the cardiac extremity of the œsophagus; the molars +have flat crowns, with complex enamel folds. + +_Fossil Dormice._—Using the generic term _Myoxus_ in a more extended +sense than the above, it has existed in Europe from the date of the Upper +Eocene. A species nearly as large as a Guinea-Pig, with very complex +molars, is common in the Pleistocene of Malta. + + +_Family_ LOPHIOMYIDÆ. + +[Illustration: FIG. 204.—_Lophiomys imhausi_. From Milne-Edwards.] + +The genus _Lophiomys_,[312] represented only by _L. imhausi_ (Fig. +204) of North-East Africa, differs from the typical _Muridæ_ in having +the temporal fossæ roofed over by a thin plate of bone, rudimentary +clavicles, and an opposable hallux. On these grounds it has been made +the type of a family, but since all the features are Murine—the dentition +being that of a typical Cricetine—it appears doubtful whether that +distinction is justifiable. The hair forms a crest along on the back, and +is of a peculiar structure. The habits of this Rodent are arboreal. + + +_Family_ MURIDÆ. + +Skull (Fig. 203) with contracted frontals; a short and slender jugal, +generally reduced to a splint between the zygomatic processes of the +maxilla and squamosal; the lower root of the former process more or less +flattened into a perpendicular plate; typically, the infraorbital vacuity +tall, and wide above and narrow below. Lower incisors compressed; no +premolars;[313] molars rooted, or rootless, tuberculate, or with angular +enamel-folds. Pollex rudimental; tail generally nearly naked and scaly. +Habits various, but mostly terrestrial. + +This large and cosmopolitan family, which includes more than a third of +the existing Rodents, is represented by about forty genera. + +Subfamily =Hydromyinæ=.—Molars ²⁄₂ in number, rooted, and divided into +transverse lobes. Represented by two Australasian genera. + +_Hydromys._[314]—External form modified for an aquatic life. Tip of +muzzle extensively haired, so that the nostrils can be closed. Skull with +the infraorbital vacuity crescentic, scarcely narrowed below, and its +external wall without the perpendicular zygomatic plate characteristic of +most of the family; incisive foramina very small. + +Two species, with habits like those of the Water Voles, are known from +Australia, Tasmania, and New Guinea. In the typical _H. chrysogaster_ the +colour of the back is black, with an admixture of golden-coloured hairs; +the belly being of a dark golden hue.[315] + +_Xeromys._[316]—External form Murine. Tip of muzzle as in _Mus_, not as +in _Hydromys_. Toes unwebbed. Tail scaly, very finely haired. Skull as +in _Mus_, with the exception of the rounding of the supraorbital edges. +Teeth as in _Hydromys_. + +Represented by _X. myoides_, of Queensland; a species about twice the +size of the Common Mouse. This genus serves to connect _Hydromys_ with +the other Murines, although it is difficult to say to which group it +comes nearest. + +Subfamily =Platacanthomyinæ=.—Molars rooted, with transverse laminæ. +Flattened spines mingled with the hair; tail thickly haired. Represented +by one genus. + +_Platacanthomys._[317]—The one representative of this genus is _P. +lasiurus_, found in the clefts of rocks and hollow trees in Southern +India at elevations of about 3000 feet. This elegant little animal +closely resembles a Dormouse; the tail and body having a length of 6 +inches. + +Subfamily =Gerbillinæ=.—Incisors narrow; molars with transverse laminæ +(Fig. 205). Auditory bullæ very large in most cases. Hind limbs +elongated. Tail usually long and hairy. Ranges over the Palæarctic, +Oriental, and Ethiopian regions. + +_Gerbillus._[318]—Upper incisors grooved; first molar with three laminæ, +second with two, and third with one. There are some sixty species, with +a range coextensive with that of the family. The Gerbils, with their +large and bright eyes and long tufted tails, are very graceful creatures, +inhabiting sandy plains, where they form extensive burrows. Remains of +existing species are found in cavern-deposits in Madras (Fig. 205). + +[Illustration: FIG. 205.—The left ramus of the mandible of _Gerbillus +indicus_, with an enlarged view of the molars, from a cavern deposit in +Madras. (From the _Palæontologia Indica_.)] + +_Pachyuromys._[319]—The African genus _Pachyuromys_ is distinguished by +the very large size of the auditory bulla, as well as by the short and +fleshy tail, which is club-shaped. The incisors are narrow and faintly +grooved. + +_Mystromys_,[320] _Otomys_,[321] and _Dasymys_.[322]—These genera, also +from South Africa, differ from _Gerbillus_ in the form of the molars, and +are represented by a few species. + +_Malacomys._[323]—The one known species of this genus is from the Gaboon, +and is in some respect intermediate between the true Gerbils and the +Rats. Thus the dentition and feet are those of the former, but the long +scaly tail resembles that of the latter. + +Subfamily =Phlœomyinæ=.[324]—This subfamily is represented only by +_Phlœomys_[325] _cumingi_, of the Philippine Islands, in which the +incisors are very broad, the molars are divided into transverse laminæ, +and the claws are large. The muzzle is blunt; the ears are hairy +externally; the tail is moderate, and thickly haired; and the auditory +bullæ are very small. The first upper molar has three, and the others two +laminæ. + +Subfamily =Dendromyinæ=.—Incisors convex in front; molars ³⁄₃, rooted and +tuberculated. Ears hairy; claws long. Confined to the Ethiopian region. + +_Dendromys._[326]—A small Rodent, with the habits of a Dormouse, +characterised by its grooved incisors, slender form, and long, scaly +tail, which is sparsely haired. Two other Murines described as +_Steatomys_[327] and _Lophuromys_[328] are referred to this subfamily. +The first is of plump form, with a rather short and thickly haired tail, +and grooved incisors. The latter resembles _Steatomys_ in form, but has +fine flattened bristles instead of fur, and plain incisors. + +Subfamily =Cricetinæ=.—Molars ²⁄₃, tuberculate and rooted, with the +tubercles of the upper ones arranged in two longitudinal rows (Fig. 206, +_B_). This subfamily has an almost cosmopolitan distribution, and appears +to include the most generalised members of the family, from which the +more specialised _Murinæ_ have been evolved. + +_Cricetus._[329]—According to the arrangement proposed by Mr. O. +Thomas[330] this genus is taken to include both the Hamsters of the +Old World (_Cricetus_ proper) and the white-footed or Vesper Mice +(_Hesperomys_) of the New. Cheek-pouches are frequently present, and +may be very large. The first molar (Fig. 206, _B_) generally has six +tubercles. The tail may be very short. + +[Illustration: FIG. 206.—Left upper molars of _Mus_ (_A_) and _Cricetus_ +(_B_).] + +This large and unwieldy genus may be divided into a number of groups or +subgenera. The typical group includes the Hamsters of the Old World, +characterised by the large size of their cheek-pouches, the walls of +which are connected with muscles arising from the lumbar vertebræ. The +tail is remarkable for its shortness. The best-known species is _C. +frumentarius_, inhabiting Europe and Northern Asia. The American forms, +which range over the whole of that continent, comprise a number of +subgenera, of which the following are the most important. _Rhipidomys_, +including Dormouse-like forms with long tails and a dentition like +that of the typical group; _Oryzomys_, represented by Murine species; +_Calomys_, with short tail and Hamster-like body; _Vesperimus_, with +only five tubercles on the first molar; _Onychomys_, in which the +tail is extremely short and Hamster-like, and the form is Arvicoline; +_Scapteromys_, of Murine form with a long and hairy tail; _Phyllotis_, +with a shorter tail; _Habrothrix_, an Arvicoline group, with a short +and thinly haired tail; and _Oxymycterus_, distinguished from the +preceding by having a nail instead of a claw on the pollex. With regard +to the distribution of these forms Mr. Thomas[331] remarks that in +South America as we proceed southwards there is a general tendency “to +a disappearance of the tropical and northern Mouse- and Dormouse-like +subgenera _Rhipidomys_, _Vesperimus_, and _Oryzomys_, with the appearance +and increase of the Vole- and Hamster-like _Habrothrix_ and _Calomys_—a +change that is curiously paralleled in the Old World by the gradual +supercession of _Mus_ and _Myoxus_ in favour of _Arvicola_ and _Cricetus_ +as we go northwards from tropical to temperate and arctic regions.” One +species has spines in the fur. + +Remains of _Cricetus_ are abundant in the Pleistocene cavern-deposits of +Brazil, where a number of the forms are referable to existing species; +the genus is also represented in the Miocene of North America and Europe, +the species from the former area having been described as _Eomys_, and +those from the latter as _Cricetodon_. + +_Holochilus_[332] (_Nectomys_).—The Rats of this genus are allied to +the American forms of _Cricetus_, but have the third upper molars +proportionately larger and the skull more stoutly built. This genus is +confined to Brazil, and contains about six species, some of which are +the largest indigenous Rats of America. Two species are aquatic in their +habits, and have short webs between the toes of their hind feet. + +_Sigmodon_[333] differs from _Cricetus_ in the pattern of the molar +teeth. It contains one species only, the Rice-Rat, _S. hispidus_, ranging +from the United States to Ecuador. + +_Rhithrodon_,[334] and _Ochetodon_.[335]—These are more or less +like _Cricetus_, but with grooved upper incisors. The first, is a +South-American genus, and contains five Rat-like species, one from +Venezuela, another from Peru, and the other three from Patagonia. The +second consists of three North American mice, of about the size and +proportions of the English Wood-Mouse (_Mus sylvaticus_). + +_Neotoma._[336]—A peculiar North American genus, in which the teeth +simulate the prismatic appearance of those of the _Arvicolinæ_. There +are four species known as Wood-Rats, all of about the size of _Mus +decumanus_; one of them (_N. cinerea_) having a tail almost as bushy as +a Squirrel’s while the other three have ordinary scaly Rat-like tails. + +Fossil remains of _Neotoma_ from cavern-deposits in Pennsylvania are +not improbably referable to the existing Florida Rat (_N. floridana_). +_Paciculus_, from the Miocene of the United States, is regarded as an +allied extinct genus with enamel-folds to the molars. + +_Hypogeomys._[337]—This and the following genera are confined to +Madagascar, where they are the sole representatives of the Rodentia. +_Hypogeomys_ is a very peculiar form of large size, with long ears, feet, +and tail. There is only one species, _H. antimena_, a fawn-coloured Rat +about 9 inches long. + +_Nesomys._[338]—Contains two species of long-haired Rats, more or less +rufous in colour, about the size of the Brown Rat. + +_Brachytarsomys._[339]—Represented only by _B. albicauda_, a pretty +velvety-haired fawn-coloured Rat, with short feet and a long tail. + +_Hallomys._[340]—The only species (_H. audeberti_) is very like a +_Nesomys_, but has much longer hind feet. + +_Eliurus._[341]—Represented by one small Dormouse-like species, +characterised by its nearly naked and short ears, and long tail, of which +the proximal third is scaly, and the remainder covered with long hair. +The pollex is rudimental, but the hallux well developed. + +Subfamily =Arvicolinæ=.—Molars usually imperfectly rooted or rootless, +and composed of two longitudinal rows of triangular prisms placed +alternately (Fig. 207). Tail moderate or short. Common to the Palæarctic +and Nearctic regions. + +[Illustration: FIG. 207.—Upper (_A_) and lower (_B_) molars of the +Water-Vole (_Arvicola amphibius_).] + +The Voles, as the members of this group are commonly termed, are so +closely connected with the Cricetines that they may be regarded merely as +a branch of that subfamily which has attained a peculiarly specialised +type of molar dentition. The Voles are externally distinguished, as a +rule, from true Rats and Mice by their more clumsy and heavy build and +less graceful movements; by the small size of their eyes, the bluntness +of the muzzle, the small ears, and the shorter limbs and tail. + +_Phenacomys._[342]—A North American genus distinguished by its rooted +molars, and thus connecting the typical forms with Cricetines like +_Neotoma_. Several species have been described by Dr. C. H. Merriam. + +_Arvicola._[343]—The type genus _Arvicola_ has rootless molars, and naked +soles to the feet. It includes over forty species inhabiting Europe, +North America, and Asia, a few species entering into the northern limits +of the Oriental region in India. Three species of the genus are found +in the British Isles, of which the following account is given by Mr. O. +Thomas:— + +The common Water-Vole (_A. amphibius_) is as large as the Brown Rat. +Its fur is long, soft, and thick, of a uniform grizzled brown all over, +except when, as is not uncommon, it is wholly black. The tail is about +half the length of its head and body, and the hind feet are unusually +long and powerful, although not webbed, and have five rounded pads +on their lower surfaces. Its molar teeth (see Fig. 207) present the +following number of prismatic spaces:—in the upper jaw the first, or +anterior, has 5, the second 4, and the third 4, of which the last is very +irregular in shape, and is sometimes itself divided into two, making 5 +in all; in the lower jaw the first has 7 spaces, of which the 3 anterior +are generally not fully separated from one another, the second has 5, +and the third 3. These numbers for the different teeth are taken as the +characters of the subgenus _Paludicola_ of Dr. Blasius, by whom this +method of subdividing the genus was first introduced. The Water-Vole +is one of the commonest English mammals, and is perhaps the most +often actually seen of all, owing to its diurnal habits. It frequents +rivers and streams, burrowing deeply into their banks, and in this way +often causing considerable damage. Its food consists almost wholly of +water-weeds, rushes, and other vegetable substances, but, like so many +other Rodents, it will also occasionally eat animal food, in the shape +of insects, mice, or young birds. The female during the warm season of +the year has three or four litters, each of from two to seven young. +The range of the Water-Vole extends over the whole of Europe and North +Asia, from England to China, but it is not found in Ireland. The common +Field-Vole, or short-tailed Field-Mouse (_A. agrestis_), representing +the subgenus _Agricola_, is about the size of a House-Mouse, but with +a short stumpy body, and a tail only about one third the length of the +head and body combined. Its hind feet have six pads on their inferior +surfaces. The colour is dull grizzled brown above, and grayish-white +below. Its molar teeth have respectively 5, 5, and 6 prismatic spaces +above, and 9, 5, and 3 below. The Field-Vole is one of the commonest of +our smaller mammals, and frequents fields, woods, and gardens in enormous +numbers, often doing very considerable damage in the latter, owing to its +fondness for garden produce of all kinds. It is spread over the whole +of Great Britain from the Hebrides southwards. Abroad its range extends +from Finland to North Italy and from France and Spain to Russia. The +Bank-Vole (_A. glareolus_) resembles in size and general appearance the +common Field-Vole, but may be distinguished by its more or less rusty or +rufous-coloured back, its larger ears, and the relatively longer tail, +which attains to about half the length of the head and body. Its molar +teeth present characters so different from those of all other Voles as +to have caused it to be regarded as belonging to an entirely distinct +genus, for which the name of _Evotomys_ has been used. Their chief +distinction lies in the fact that, unlike those of all other Voles, their +pulp-cavities close up in adult life, and they form distinct roots, more +resembling those of the ordinary Rats and Mice. The enamel-spaces of +these teeth number respectively 5, 4, and 5 above, and 7, 3, and 3 below. +The habits of this species are in every way similar to those of the +Field-Vole. Its range in Great Britain extends northwards to Morayshire, +beyond which it has not yet been observed. It is also found all along +the north temperate zone from France to China, and is replaced in North +America by a closely allied animal known as _A. gapperi_. It is probable, +however, that both _A. gapperi_ and _A. glareolus_ are only southern +climatic offshoots of a still more northern species, the _A. rutilus_ of +Northern Europe, Siberia, and Arctic America. + +Fossil remains of _Arvicola_ are common in European Pleistocene deposits, +and they have also been obtained from the Upper Pliocene of the Norwich +Crag. + +_Synaptomys._[344]—Represented by one North American species, having +grooved upper incisors, skull and molars like those of _Myodes_, with the +external characters of _Arvicola_. + +_Myodes._[345]—Distinguished from _Arvicola_ by the more clumsy build, +convex obtuse head, extremely short and Rabbit-like tail, short ears, +small feet, the soles of which are furred, elongated claws, and thick +fur, as well as by the breadth and massiveness of the skull, in which the +zygomatic arch has a laminar expansion and the palate a peculiar contour; +while the root of the lower incisor does not extend behind the last +molar, the upper incisors are bevelled, and not grooved, and the molars +have a characteristic pattern, which cannot be well explained without a +figure. + +[Illustration: FIG. 208.—The Lemming (_Myodes lemmus_).] + +The Lemmings, as the members of the genus are commonly called, are +represented by the Norwegian Lemming (_M. lemmus_, Fig. 208), and the +North American _M. obensis_. Different individuals of the Norwegian +Lemming vary considerably both in size and colour, but its usual length +is about 5 inches, and its soft fur yellowish brown, marked with spots +of dark brown and black. It has a short, rounded head, obtuse muzzle, +small bead-like eyes, and short rounded ears, nearly concealed by the +fur. The tail is very short. The feet are small, each with five claws, +those of the fore feet strongest, and fitted for scratching and digging. +The usual dwelling place of the Lemmings is in the highlands or fells of +the great central mountain chain of Norway and Sweden, from the southern +branches of the Langfjeldene in Christiansand-stift to the North Cape and +the Varangerfjord. South of the Arctic circle they are, under ordinary +circumstances, exclusively confined to the plateaus covered with dwarf +birch and juniper above the conifer region, though in Tromsö-amt and in +Finmarken they occur in all suitable localities down to the level of the +sea. The nest is formed under a tussock of grass or a stone, constructed +of short dry straws, and usually lined with hair. The number of young +in each nest is generally five, sometimes only three, but occasionally +seven or eight, and at least two broods are produced annually. Their +food is entirely vegetable, especially grass-roots and stalks, shoots of +the dwarf birch, reindeer-lichens, and mosses, in search of which they +form, in winter, long galleries through the turf or under the snow. They +are restless, courageous, and pugnacious little animals. When suddenly +disturbed, instead of trying to escape they will sit upright, with their +back against a stone or other coign of vantage, hissing and showing fight +in a very determined manner (Fig. 208). + +The circumstance which has given more popular interest to the Lemming +than to a host of other species of the same order of animals is that +certain districts of the cultivated lands of Norway and Sweden, where +in ordinary circumstances they are quite unknown, are occasionally and +at very uncertain intervals, varying from five to twenty or more years, +literally overrun by an army of these little creatures, which steadily +and slowly advance, always in the same direction, and regardless of +all obstacles, swimming across streams and even lakes of several miles +in breadth, and committing considerable devastation on their line of +march by the quantity of food they consume. In their turn they are +pursued and harassed by crowds of beasts and birds of prey, as bears, +wolves, foxes, dogs, wild cats, stoats, weasels, eagles, hawks, and +owls, and never spared by man; even the domestic animals not usually +predaceous, as cattle, goats, and reindeer, are said to join in the +destruction, stamping them to the ground with their feet, and even eating +their bodies. Numbers also die from diseases apparently produced from +overcrowding. None ever return by the course by which they came, and the +onward march of the survivors never ceases until they reach the sea, +into which they plunge, and swimming onwards in the same direction as +before perish in the waves. These extraordinary and sudden appearances +of vast bodies of Lemmings, and their singular habit of persistently +pursuing the same onward course of migration, have given rise to various +speculations, from the ancient belief of the Norwegian peasants, shared +in by Olaus Magnus, that they fall down from the clouds, to the almost +equally untenable hypothesis, ingeniously maintained by the late Mr. W. +D. Crotch, that they are acting in these migrations in obedience to an +instinct inherited from vastly ancient times, and are still seeking the +congenial home in a supposed submerged Atlantis, to which their ancestors +of the Miocene period were wont to resort when driven from their ordinary +dwelling-places by crowding or scarcity of food. The principal really +ascertained facts regarding these migrations seem to be as follows. +When any combination of circumstances has occasioned an increase in the +numbers of the Lemmings in their ordinary dwelling-places, impelled by +the restless or migratory instinct possessed in a less developed degree +by so many of their congeners, a movement takes place at the edge of the +elevated plateau, and a migration towards the lower-lying land begins. +The whole body moves forward slowly, always advancing in the same general +direction in which they originally started, but following more or less +the course of the great valleys. They only travel by night; and, staying +in congenial places for considerable periods, with unaccustomed abundance +of provender, notwithstanding all the destructive influences to which +they are exposed, they multiply excessively during their journey, having +families still more numerous and more frequently than in their usual +homes. The progress may last from one to three years, according to the +route taken, and the distance to be traversed until the sea-coast is +reached, which in a country so surrounded by water as the Scandinavian +peninsula must be the ultimate goal of such a journey. This may be either +the Atlantic or the Gulf of Bothnia, according as the migration has +commenced from the west or the east side of the central elevated plateau. +Those that finally perish in the sea, committing what appears to be a +voluntary suicide, are only acting under the same blind impulse which has +led them previously to cross smaller pieces of water with safety. + +_Cuniculus._[346]—Cranial and incisive characters those of _Myodes_, in +the main, but the molars more of an Arvicoline type, the first upper one +differing from that of all other members of the family in having seven +prisms. Externally of the general shape of _Myodes_, but distinguished +by the absence of external ears, the shortness and dense furring of the +feet, the obsolete pollex with rudimentary nail, and the great length of +the two middle claws of the manus. Represented by one species, the Banded +Lemming (_C. torquatus_), of the Arctic region. + +Remains of both _C. torquatus_ and _Myodes lemmus_ occur in British +Pleistocene deposits. + +_Fiber._[347]—Closely allied to _Arvicola_, both externally and in +cranial and dental characters, but with the tail nearly as long as the +body (apart from the head), compressed, nearly naked, and reticulate. +Feet incompletely webbed, and the whole body adapted for a thoroughly +aquatic life. + +The Musk-Rat or Musquash (_F. zibethicus_, Fig. 209) is the only +representative of this genus, and the largest member of the subfamily, +the head and body being about 12 inches in length. It is rather a heavily +built animal, with a broad head, no distinct neck, and short limbs; the +eyes are small, and the ears project very little beyond the fur. The fore +limbs have four toes and a rudimentary thumb, all with claws; the hind +limbs are larger, with five distinct toes, united by short webs at their +bases. The tail is laterally compressed, nearly naked, and scaly. The +hair much resembles that of a beaver, but is shorter; it consists of a +thick soft under-fur interspersed with longer stiff, glistening hairs, +which overlie and conceal the former on the upper surface and sides of +the body. The general colour is dark umber-brown, almost black on the +back and gray below. The tail and naked parts of the feet are black. The +musky odour from which it derives its name is due to the secretion of a +large gland situated in the inguinal region, and present in both sexes. + +[Illustration: FIG. 209.—The Musk-Rat (_Fiber zibethicus_.)] + +The Musk-Rat is peculiar to America, being extensively distributed in +suitable localities in the northern part of the continent, extending +from the Atlantic to the Pacific, and from the Rio Grande to the barren +grounds bordering the Arctic Seas. It is aquatic in its habits, living on +the shores of lakes and rivers, swimming and diving with great facility, +feeding on the roots, stems, and leaves of water-plants, or on fruits +and vegetables which grow near the margin of the streams it inhabits. +Musk-Rats are most active at night, spending the greater part of the day +concealed in their burrows dug out of the bank, consisting of a chamber +with numerous passages, all of which open under the surface of the +water. For winter quarters they build more elaborate houses of conical +or dome-like form, composed of sedges, grasses, and similar materials +plastered together with mud. As their fur is an important article of +commerce, large numbers are annually killed, being either trapped or +speared at the mouths of their holes. + +The skull of the Musk-Rat is shown in Fig. 203 (p. 459); its structure +is essentially Arvicoline, but the squamosals are greatly expanded, +with a corresponding reduction of the parietal and interparietal, and +the interorbital constriction of the frontals attains its greatest +development. Fossil remains of _Fiber_ occur in the North American +Pleistocene. + +_Neofiber._[348]—This genus, while agreeing with _Fiber_ in the +characters of the skull and teeth, differs by the cylindrical tail, and +the normal form of the feet, in which the toes are not bent laterally +at an angle with the sole. The single species _N. alleni_, commonly +known as the Round-tailed Musk-Rat, is found in Florida, and is much +less completely aquatic in its habits than _Fiber_. Its colour is brown +above, and silvery-white mixed with rufous below, the sides of the body +gradually shading from brown to rufous, the forehead and the tip of the +nose are black, while the tail is rufous mingled with black. + +Subfamily =Siphneinæ=.—Includes two genera of Mole-like Rodents with +an _Arvicoline_ dentition, but with the body thoroughly adapted for a +subterranean life, the limbs and tail being very short, and the external +ears rudimentary. Both are Palæarctic. + +_Ellobius._[349]—The Russian _E. talpinus_, the typical representative of +the genus, has short claws, and comes nearest to the _Arvicolinæ_. _E. +fuscocapillus_ is from Afghanistan. + +[Illustration: FIG. 210.—_Siphneus armandi._ (From Milne-Edwards.)] + +_Siphneus._[350]—This genus (Fig. 210) includes species inhabiting +Northern and Central Asia, and is characterised by the great length of +the claws of the manus. Remains of an existing species occur in the +Pleistocene of the Altai, while an extinct one has been described from +the Pliocene of North China. + +Subfamily =Deomyinæ=.—Represented only by the under-mentioned genus, +in which the bituberculate anterior and tricuspidate middle ridge of +the first upper molar presents a condition intermediate between that +obtaining in the _Cricetinæ_ and that of the _Murinæ_. + +_Deomys._[351]—Externally as in _Mus_. Pollex with a narrow nail; hind +feet elongate. Infraorbital vacuity of skull triangular, not narrowed +below. Upper incisors with a pair of minute grooves. First upper molar +with seven distinct tubercles, of which three are placed on the middle +ridge, and two on each of the others. One species, _D. ferrugineus_, from +the Lower Congo, an animal about the size of the Common Mouse. + +Subfamily =Murinæ=.—Molars rooted and tuberculated; those of the upper +jaw with three longitudinal rows of tubercles (Fig. 206, _A_). + +This group includes the true Rats and Mice, and may be regarded as more +specialised than the _Cricetinæ_. All the members of the group closely +resemble one another, and are light and active, with large ears, bright +eyes, and long and scaly tails. Their coloration, in conformity with the +fossorial and nocturnal habits of most of the forms, is sombre, and their +movements are remarkably agile and graceful. + +[Illustration: FIG. 211.—The Australian Brown-footed Rat (_Mus +fuscipes_). After Gould.] + +_Mus._[352]—Incisors narrow, without grooves. Structure of molars as +in Fig. 206, _A_ (p. 463). Incisive foramina of skull long; coronoid +process of mandible well developed. Ears and eyes large; muzzle naked at +the extremity. Fur soft, in some cases intermingled with spines. Pollex +with a short nail in place of a claw. No cheek-pouches. Tail long, nearly +naked, with rings of overlapping scales. Vertebræ: C 7, D 13, L 6, S 4, C +26-32. + +This genus is the largest in the whole mammalian class, comprising not +less than 130 species, ranging over the whole of the Old World, with +the noteworthy exception of Madagascar. On the whole, the species are +more numerous in tropical than in temperate regions, and very few occur +in cold countries. Many of the species living in warm climates have +flattened spines mingled with the fur; these spines being shed in winter, +when a warmer covering is necessary, and replaced by hair. Five species +occur in England, which are briefly noticed below; and it may be observed +that none of the species are much larger than _M. decumanus_ or smaller +than _M. minutus_. As a rule the habits of the species are similar to +those of the English forms, but a few are arboreal, while others again, +like the one represented in Fig. 211, are aquatic. The earliest known +representatives of the genus (excluding _Acanthomys gaudryi_ of the Lower +Pliocene Pikermi beds of Attica) occur in the Pleistocene of Europe. + +[Illustration: FIG. 212.—_A_, Head of Brown Rat (_M. decumanus_). _B_, +Head of Black Rat (_Mus rattus_).] + +The Brown or Norway Rat (_M. decumanus_) is a heavily built animal, +growing to 8 or 9 inches in length, with a bluff rounded head, small ears +(Fig. 212, _A_), and a comparatively short tail, which is always shorter +than the head and body combined, and generally not longer than the body +alone. The colour is a uniform grayish-brown above and white below, +the ears, feet, and tail being flesh coloured. Black varieties, which +are often mistaken for true Black Rats, are by no means rare, but the +differences in size and proportions form a ready means of distinguishing +the two. The Brown Rat is believed to be a native of Western China, +where a race (_M. humiliatus_) has been discovered so like it as to be +practically indistinguishable. Both this, and the next species agree in +their predaceous habits, omnivorous diet, and great fecundity. They bear +four or five times in the year from four to ten blind and naked young, +which are in their turn able to breed at an age of about six months; the +time of gestation being about twenty days. + +The Black Rat (_M. rattus_) is a smaller and more lightly built species, +generally not more than 7 inches in length, with a slender head (Fig. +212, _B_), large ears, and a thin tail of about 8 or 9 inches in length. +The colour is usually a glossy bluish-black, somewhat lighter below; but +in the tropical variety described as _M. alexandrinus_ the general colour +is gray or rufous, and the belly white. The disposition of the Black Rat +is milder than that of _M. decumanus_, and the white and pied rats kept +as pets mostly belong to this species. In many localities where it was +formerly abundant it has been entirely superseded by _M. decumanus_, but +it is said that in some parts of Germany it has been lately reasserting +itself. + +_M. musculus_, the Common House-Mouse, is, like the Brown Rat, originally +a native of Asia, whence it has spread to all the inhabited parts of +the globe. Its habits and appearance are too well known to need any +description. + +_M. sylvaticus_, the Wood or Long-tailed Field-Mouse, is very common in +many parts of England, often taking to barns and outhouses for shelter +during the winter. It is of about the same size and proportions as _M. +musculus_, but of a bright reddish-gray colour, with a pure white belly. + +_M. minutus_, the Harvest-Mouse, is the smallest of the European Mice, +seldom exceeding 2½ or 3 inches in length. It is of a yellowish-red +colour, with comparatively short ears and tail. It lives entirely away +from human habitations, generally dwelling in grass or corn-fields, where +it builds a globular nest of dried grass of the size of a cricket-ball, +in which the young are nurtured. + +_Nesocia._[353]—General characters those of _Mus_, but the incisors and +molars very much wider, and the tubercles of the latter more connected by +transverse ridges, thus producing a laminated type of structure. + +This genus has been placed by some writers in a distinct subfamily with +_Phlœomys_, but Mr. O. Thomas regards it as so closely allied to _Mus_ +that even its generic separation may be open to question. It comprises +several species, mostly spread over Southern Asia, ranging from Palestine +to Formosa, and from Kashmir to Ceylon, but _N. scullyi_ is found in +Turkestan. The great Indian Bandicoot-Rat (_N. bandicota_) is the largest +representative of the subfamily, often exceeding a foot in length. _N. +bengalensis_ is remarkable for possessing no less than eighteen mammæ. +Fossil remains of _Nesocia_ occur in the Pleistocene of Madras and in the +Pliocene of Northern India; those from the first-named deposits being +referable to existing species. + +_Golunda._[354]—Like _Mus_, but with a distinct groove down the front of +the upper incisors. There are only three species, one from Western India, +one from West Africa, and the other from Eastern Africa. + +_Uromys._[355]—Differs from _Mus_ in having the scales of the tail not +overlapping, but set edge to edge, so as to form a sort of mosaic work. +There are about six species of _Uromys_, spread over the northern part of +the Australian region from the Aru Islands to Queensland. + +_Chiruromys._[356]—Externally like _Mus_, but with the terminal portion +of the tail without scales above, quite naked, transversely wrinkled, +and prehensile. Scales of remainder of tail more or less pentagonal, +and arranged in oblique diagonal series. Supraorbital vacuity of skull +without projecting plate in external wall. Incisive foramina short +and narrow; auditory bulla small. Upper molars very complex, with the +tubercles (of which there are eleven in the first tooth) low, and +distinctly arranged in transverse rows. Known only by _C. forbesi_, from +mountains in New Guinea, which must be regarded as a specialised form +very similar in outward appearance to _Uromys cervinipes_. + +_Hapalotis._[357]—Hind limbs elongated. Incisive foramina very large. No +coronoid process to the mandible. This genus is confined to Australia, +where there are about fifteen species known. They are pretty little +animals, with long ears and tail, and in many respects resemble the +Jerboas, whose place they seem to take in the sandy Australian deserts. +Remains of _H. albipes_ occur in the Pleistocene of New South Wales. + +_Mastacomys._[358]—Like _Mus_, but with the molars remarkably broadened, +and with only four mammæ. The single species of the genus is as yet only +known from Tasmania, though it has been found fossil in New South Wales; +it is somewhat similar in size and general appearance to the English +Water-Vole, but has much longer and softer fur. + +_Acanthomys._[359]—Fur almost entirely composed of flattened spines. +Teeth and skull as in _Mus_, but the coronoid process of mandible +very small. There are six species of Spiny-Mice known, all of about +the size of the Common Mouse. They are found in Syria, Palestine, and +Eastern Africa as far south as Mozambique. _A. dimidiatus_ presents the +appearance of a little Hedgehog when its spines are erected; it inhabits +the stony deserts of Arabia Petræa and Palestine, and feeds on bulbs. A +fossil Mouse (_A. gaudryi_) referred to this genus occurs in the Lower +Pliocene of Attica. + +_Echinothrix._[360]—A very remarkable rat with an extremely elongated +muzzle, all the bones of the face being much produced. The incisors are +faintly grooved. The only species is _E. leucura_, an animal of about +the size of the Brown Rat, with its fur thickly mixed with spines. It is +found in Celebes. + +_Typhlomys._[361]—This genus is represented by a single species from +China, which resembles a House-Mouse in size and general appearance, but +has smaller ears, while the eyes are so reduced in size as to be totally +concealed by the long eyelashes. + +_Cricetomys_[362] and _Saccostomus_.[363]—These two African genera +have been—from the presence of cheek-pouches—usually placed in the +neighbourhood of _Cricetus_, but their molars are of the Murine type. +_Cricetomys_ is said to have grooved upper incisors, and is represented +only by _C. gambianus_. There are two species of _Saccostomus_. + +_Pithechirus._—A small Rodent from Sumatra and Java described under this +name is a true Mouse, having nothing to do with _Chiropodomys_, to which +it has been compared. + + +_Family_ SPALACIDÆ. + +Mole-like forms, with very small or rudimentary eyes and ear-conchs, +large claws, and short or rudimentary tail. Form cylindrical. Incisors +large; premolars present or absent; molars rooted, with re-entering +enamel-folds; palate narrow. + +Subfamily =Spalacinæ=.—Angular part of the mandible arising from the +lower edge of the socket of the lower incisor. No premolars. + +_Spalax._[364]—Represented by the great Mole-Rat (_S. typhlus_) of +South-Eastern Europe, in which the eyes are completely covered by the +skin. + +_Rhizomys._[365]—Eyes uncovered, although very minute; small naked +ear-conchs; and a short partially hairy tail. Includes several species +from Northern India, Tibet, China, Burma, Malaya, and Eastern Africa. A +fossil species occurs in the Pliocene Siwaliks of Northern India. + +Subfamily =Bathyerginæ=.—Angular part of the mandible arising from the +side of the socket of the lower incisor. Premolars absent or present. +Confined to the Ethiopian region. + +_Bathyergus._[366]—Upper incisors strongly grooved; _p_ ¹⁄₁, _m_ ³⁄₃; no +ear-conchs; very powerful claws. One species (_B. maritimus_), from South +Africa, attaining a length of about 10 inches. + +_Georychus_[367] and _Myoscalops_.[368]—Upper incisors without grooves. +_Georychus_, with some half dozen species, generally has _p_ ¹⁄₁; +_Myoscalops_, with one species, usually has _p_ ³⁄₃, and the second toe +of the foot is the longest. In _Georychus_ the premolar may be wanting, +and some examples of _Myoscalops_ have only two teeth of this series. + +_Heterocephalus._[369]—Small and nearly naked forms, with small head, +small eyes, no ear-conchs, moderately long tail, and powerful fore feet +provided with a pair of large pads; _p_ ⁰⁄₀, _m_ ²⁻³⁄₂₋₃. Two species. +These very remarkable little Rodents are regarded by Mr. O. Thomas as +very closely allied to _Georychus_, but specialised, and, so to speak, +somewhat degraded for a purely subterranean life, for which their +hairless body is peculiarly adapted. They are found in Somali-land, where +they burrow in the sandy soil. + + +_Family_ GEOMYIDÆ.[370] + +Terrestrial or fossorial forms, with large cheek-pouches opening on +the cheeks outside the mouth. Squamosal much expanded, and the jugal +extending forwards to the lachrymal. _P_ ¹⁄₁; molars rooted or rootless, +with transverse laminæ. Nearctic and Neotropical regions. + +Subfamily =Geomyinæ=.—Incisors broad; mastoid not appearing on the top +of the skull; eyes small; ear-conch rudimentary; limbs short, subequal. +Habits fossorial. + +_Geomys._[371]—Upper incisors deeply grooved. The common North American +Pouched-Rat or “Pocket-Gopher” (_G. bursarius_) inhabits the plains +of the Mississippi and lives in burrows. Several other species are +recognised from the Southern United States, Mexico, and Central America. +The genus is represented in the Pleistocene and Pliocene of the United +States. + +_Thomomys._[372]—Upper incisors plain. Represented by two species, with +numerous varieties found all over Canada and North America west of the +Rocky Mountains. Remains referred to an existing species occur in the +Pliocene of Oregon. _Entoptychus_, from the Miocene of the United States, +is an allied genus, with broad incisors and rootless molars. + +Subfamily =Heteromyinæ=.—Incisors narrow; mastoid appearing largely on +the top of the skull; eyes and ears moderate or large; hind limbs and +tail elongated. Habits terrestrial. + +_Dipodomys._[373]—This genus is characterised by the rootless molars. It +is best known by _D. phillipsi_, the Kangaroo-Rat of the desert regions +east of the Rocky Mountains, having habits like those of the Jerboas. The +typical forms have four toes in the pes; but in others, which it has been +proposed to separate as _Dipodops_, there are five: _D. ordi_ and _D. +agilis_ belong to the latter group. + +_Perognathus_[374] and _Heteromys_.[375]—In both these genera, which are +represented by species of very small size, the molars are rooted; the +latter being distinguished by the presence of flattened spines mingled +with the fur, and having species ranging into South America. According to +Dr. C. H. Merriam the forms described as _Cricetodipus_ are not separable +from _Perognathus_; while Dr. Coues considers that _Saccomys_ was founded +upon a species of _Heteromys_. _Pleurolichus_, from the Miocene of the +United States, is regarded as an extinct genus allied to _Heteromys_. + + +_Family_ DIPODIDÆ. + +Terrestrial forms usually with four upper cheek-teeth, and typically with +the following characters. Incisors compressed; molars with transverse +enamel-folds; infraorbital vacuity of skull (Fig. 7, p. 37) large and +rounded; jugal ascending in front to the lachrymal; and the mastoid part +of the auditory bulla usually very large. + +Subfamily =Sminthinæ=.—Molars rooted; _p_ ¹⁄₀, _m_ ³⁄₃. Skull with the +infraorbital vacuity widest below, and the incisive palatal foramina +long. Limbs short. Palæarctic. + +_Sminthus._[376]—Represented by the Rat-like _S. vagans_ from Northern +Europe and Asia, in which the ears are rather long and pointed, the tail +is covered with short hairs and nearly as long as the body, while the +molars present a somewhat complicated pattern. This genus has generally +been regarded as an aberrant member of the _Muridæ_, but was transferred +in 1887 to the present family by Dr. H. Winge. + +Subfamily =Zapodinæ=.—Molars rooted; _p_ ¹⁄₁, _m_ ³⁄₃; cervical vertebræ +free; hind limbs elongated; metatarsals separate; hind feet with five +digits. Nearctic region. + +_Zapus._[377]—The American Jumping-Mouse (_Z. hudsonianus_) extends over +almost the whole North-American continent from Labrador to Mexico. + +Subfamily =Dipodinæ=.—Molars rooted; _p_ ⁰⁻¹⁄₀₋₁, _m_ ³⁄₃; cervical +vertebræ more or less ankylosed; hind limbs elongated; metatarsals +united; hind feet with only three functional digits. Palæarctic and +Ethiopian regions. + +This subfamily includes the true Jerboas, and contains three +genera: _Dipus_[378] with three toes, and _Alactaga_[379] and +_Platycercomys_[380] with five, the outer two not reaching to the ground. +The latter is distinguished by the absence of premolars, and comprises +many species extending from Siberia to Nubia. + +Remains of the existing _Alactaga decumana_[381] occur in the Pleistocene +of Germany, and those of _Zapus hudsonianus_ in the corresponding +strata of the United States. _Platycercomys_ has been recorded from the +Pleistocene of Northern Asia. + +Subfamily =Pedetinæ=.—Molars rootless; cervical vertebræ free; hind limbs +elongated; metatarsals separate; hind feet with four digits. Vertebræ: C +7, D 12, L 7, S 3, C 30. Ethiopian region. + +_Pedetes_,[382] the Cape Jumping-Hare (_P. caffer_), by far the largest +species of the family, extends from Mozambique and Angola to the Cape of +Good Hope. + + +_Section_ HYSTRICOMORPHA. + +Skull (Fig. 213) with a stout zygomatic arch; jugal not supported below +by a continuation of the maxillary zygomatic process; infraorbital +vacuity large; mandible with the angular part arising from the outer side +of the bony socket of the lower incisor. Clavicles perfect or imperfect; +fibula distinct. One premolar in each jaw. + + +_Family_ OCTODONTIDÆ. + +Clavicles complete. Skull with long incisive foramina extending into the +maxillæ; and usually an inferior angle to the jugal. Molars with external +and internal enamel-folds; _p_ ¹⁄₁, except in _Ctenodactylus_. Mammæ +placed high up on the sides of the body. Confined to the Ethiopian and +Neotropical regions, with the exception of one species of _Echinomys_ +which ranges into Central America. Habits mostly terrestrial, but +occasionally fossorial or natatorial. + +Subfamily =Ctenodactylinæ=.—Molars semi-rooted; jugal as in _Dipodidæ_; +the two inner toes of the hind feet with a horny comb and rigid bristles. +Ethiopian region. + +_Ctenodactylus._[383]—Represented only by _C. gundi_ from North Africa, +on the borders of the Sahara. Has no premolars; each foot has four +digits; the hind limbs are rather longer than the fore; the ears small; +and the tail reduced to a stump. This animal is about the size of the +Water-Vole, and dwells on rocky ground, its habits being diurnal. The +peculiar comb-like inner toes are employed for dressing the fur. + +[Illustration: FIG. 213.—Skull of _Hydrochœrus capybara_ (reduced).] + +_Pectinator._[384]—Closely allied to the preceding, but with a minute +premolar in each jaw; and a moderately long and bushy tail. One species +(_P. spekei_), from Somali-land. + +Subfamily =Octodontinæ=.—Molars semi-rooted or rootless, with simple +enamel-folds; fur soft. There are some six existing genera, including +Rat-like species, all of which are South American, except _Petromys_, +which is Ethiopian. + +_Octodon._[385]—Upper and lower molars alike; ears moderate; tail of +medium length and tufted. Vertebræ: C 7, D 12, L 7, S 4, C 25. Typically +represented by _C. cumingi_ of Chili and Peru, with other species from +Chili and Bolivia. They live in large communities. + +_Habrocoma._[386]—Lower molars more complex than the upper; ears large; +and fur extremely soft. Two Bolivian species. + +_Schizodon._[387]—One species, inhabiting elevated spots in the Southern +Andes, and characterised by the enamel-folds of the upper molars meeting +in the middle line. The external characters are much the same as in +_Ctenomys_, but the ears are larger and the claws shorter. + +_Ctenomys._[388]—Incisors broad; molars rootless, with kidney-shaped +crowns; last molar small and cylindrical; eyes and ears very small; claws +larger than the toes. Some four species. Fossil remains are common in the +Pleistocene of Buenos Ayres and the cavern-deposits of Brazil. Habits +fossorial. + +_Spalacopus._[389]—Represented by two Chilian species, distinguished +from the preceding genus by the rudimentary ears. These rodents store up +magazines of food in their burrows. + +_Petromys._[390]—The South African _P. typicus_ is closely allied to +_Spalacopus_, but differs by its harsh fur, the shortness of the pollex, +and the somewhat bushy tail. The teeth are semi-rooted, with single inner +and outer enamel-folds, nearly meeting in the middle. + +Subfamily =Echinomyinæ=.—Molars semi-rooted or rootless, with deep and +curved enamel-folds; fur more or less harsh, frequently mixed with +spines; tail generally long. One Ethiopian genus, and the remaining nine +or so Neotropical. Many of the species are of large size, some being +arboreal and others aquatic. + +_Myopotamus._[391]—Incisors very large; molars with two internal and two +external enamel-folds in the upper, and three internal and one external +in the lower jaw, last molar the largest; ears moderate; tail about +two-thirds the length of the head and body, scaly, and sparsely haired; +hind feet webbed; five digits. Vertebræ: C 7, D 13, L 6, S 4, C 25. The +well-known Coypu (_M. coypu_), the only existing representative of this +genus, is one of the largest living members of the order, and attains a +length of about 2 feet. It is common in South America, living in burrows +near water, and feeding on aquatic plants. Fossil remains of the genus +occur in the caverns of Brazil, as well as in the Tertiaries of Argentina. + +_Capromys._[392]—This genus comprises arboreal forms from the West +Indies allied to the Coypu, but, according to Dr. G. E. Dobson, showing +signs of affinity with the _Hystricidæ_. The incisors are smaller than +in the Coypu, and the upper molars have one internal and two external +enamel-folds; the ears are comparatively small; the tail usually of +considerable length, and the general form somewhat Rat-like. The typical +_C. pilorides_ is somewhat smaller than the Coypu, and is confined to +Cuba; it is remarkable for the subdivision of the lobes of the liver +into a number of lobules. _C. brachyurus_ and _C. prehensilis_ are also +confined to Cuba. In Jamaica the genus is represented by _C. melanurus_, +which is somewhat smaller than a Rabbit, and has no secondary lobulation +of the liver.[393] + +_Aulacodus._[394]—Upper incisors with three deep grooves; molars as +in _Capromys_. Fur very harsh; tail moderate, sparsely haired; manus +with rudimentary pollex, and small fifth digit; pes with no hallux, and +rudimental fifth digit. One species (_A. swinderianus_), from Western and +Southern Africa, which attains a length of nearly 2 feet, and dwells in +burrows. + +_Plagiodon._[395]—Allied to _Capromys_, but with the enamel-folds of the +molars very complex, and forming a kind of zig-zag pattern in those of +the upper jaw. Represented only by _P. ædium_ of Hayti and Jamaica. + +_Loncheres_[396] and _Echinomys_.[397]—These genera include small South +American species, in most of which flattened lanceolate spikes are +mingled with the fur. The majority of the species occur in Guiana and +Brazil, but one species of _Echinomys_ has been recorded from Central +America. Fossil remains of both genera occur in the cavern-deposits of +Brazil. + +_Mesomys._[398]—This genus resembles _Loncheres_ externally, but the +pollex has a short curved claw, and there are no spines in the fur. + +_Dactylomys._[399]—A Brazilian genus presenting the following distinctive +features. Ears short; tail long and scaly; pollex minute; third and +fourth digits of manus elongated, with short convex nails. Incisors flat; +molars divided into two lobes, each of which has a single enamel-fold. +Represented by two species, _D. typus_ and _D. amblyonyx_, both of which +seem to be rare and but little known. In the elongation of some of the +digits _Dactylomys_ recalls _Chiromys_ among the Primates. + +_Cercomys._[400]—This South American genus is usually placed near +_Carterodon_, from which it is readily distinguished by the pointed +muzzle and the plain incisors. + +_Carterodon._[401]—This genus, which was originally described upon the +evidence of skulls from the Brazil caves, but subsequently found living, +is readily distinguished by the broad and grooved incisors. The upper +molars have one inner and two outer enamel-folds; those of the lower jaw +being the reverse of this. + +_Fossil Forms._—Remains of the existing genus _Loncheres_ occur in the +Brazilian cave-deposits, which also yield the extinct _Dicolpomys_. A +large number of fossil _Octodontidæ_ from the Tertiaries of South America +have been described under many generic names, but it will be sufficient +to mention that _Phloramys_ and _Pithanotomys_ are considered to be +allied to _Ctenomys_; while _Morenia_, _Orthomys_, and _Trilodon_ show +affinity to _Myopotamus_. _Pellegrinia_, from the Pleistocene of Sicily, +may be allied both to _Ctenodactylus_ and _Octodon_. + + +_Family_ THERIDOMYIDÆ. + +This extinct family, which is represented in the Tertiaries of Europe +and the United States, comprises several genera of comparatively small +Rodents, which are regarded by Dr. Schlosser as nearly related to the +_Octodontidæ_, although connected by _Archæomys_ with the _Chinchillidæ_. +The dental formula is the same as in the _Octodontidæ_. In the typical +genus _Theridomys_, from the Lower Miocene and Upper Eocene of Europe, +the molars are rooted, and have three or four re-entering enamel-folds, +which form isolated discs on the worn crowns. _Syllophodus_, from the +Miocene of the United States, is closely allied. _Protechinomys_ and +_Trechomys_ are genera from the Phosphorites of Central France with +rooted molars; while in _Archæomys_ of the same deposits the molars are +rootless, with the enamel-folds dividing their crowns into laminæ, as in +the Chinchillas. + + +_Family_ HYSTRICIDÆ. + +Build stout. Limbs subequal. A number of long and stout spines in +the integument. Facial portion of skull short and broad, and the +jugal without an inferior angle. Molars with external and internal +enamel-folds; completely or partly rooted. + +Subfamily =Synetherinæ=.—Molars rooted; clavicles complete; upper lip +not cleft; soles tuberculated; pollex absent; four mammæ; tail generally +prehensile; spines mixed with long hairs. This group is confined to +America, all the forms except one being arboreal, and their habits less +strictly nocturnal than in the next subfamily. There are three genera. + +_Erethizon._[402]—Represented by the common Canadian Porcupine (_E. +dorsatus_), a stout heavily-built animal, with long hairs almost or quite +hiding the spines; four anterior and five posterior toes; and a short +stumpy tail. It is a native of the greater part of Canada and the United +States where there is any remnant of the original forest left. Remains of +_Erethizon_ occur in cavern-deposits in Pennsylvania. + +[Illustration: FIG. 214.—The Tree Porcupine (_Synetheres prehensilis_).] + +_Synetheres._[403]—This genus contains some eight or ten species, known +as Tree Porcupines (Fig. 214), found throughout the tropical parts of +South America, and one of them extending northwards into Mexico. They +are of a lighter build than the Ground Porcupines, are covered with +short, close, many-coloured spines, often mixed with hairs, and their +tails are always prehensile. Their hind feet have only four toes, owing +to the suppression of the hallux; but they have a peculiar fleshy pad on +the inner side of the foot, between which and the toes boughs and other +objects can be firmly grasped as with a hand. Vertebræ: C 7, D 17, L 5, +S 3, C 36. An extinct species of this genus has been described from the +cavern-deposits of Brazil. + +_Chætomys._[404]—Distinguished by the shape of its skull and the greater +complexity of its teeth. It contains only one species (_C. subspinosus_), +a native of the hottest parts of Brazil. + +Subfamily =Hystricinæ=.—Molars semi-rooted; clavicles incomplete; soles +smooth; a rudimentary pollex: six mammæ; tail not prehensile. Now +confined to the Old World, where they occur in Southern Europe, Africa, +India, and the Malay Archipelago as far eastwards as Borneo. Habits +terrestrial and nocturnal. Three genera. + +[Illustration: FIG. 215.—The Common Porcupine (_Hystrix cristata_).] + +_Hystrix._[405]—This genus is readily characterised by the inflated +skull, in which the nasal chamber is often considerably larger than the +brain-case, and by the short tail, tipped with numerous slender stalked +open quills, which make a loud rattling noise when the animal moves. +Vertebræ: C 7, D 15, L 4, S 4, C 12. The best-known member is the Common +Porcupine (_H. cristata_, Fig. 215), which occurs throughout Southern +Europe and North and West Africa, but is replaced in South Africa by +_H. africæ-australis_, and in India by the Hairy-nosed Porcupine (_H. +leucura_). + +The following account of the habits of the last-named species is from Dr. +Jerdon: “_Hystrix leucura_ is found over a great part of India, from the +lower ranges of the Himalayas to the extreme south, but does not occur +in lower Bengal, where it is replaced by _H. bengalensis_. It forms +extensive burrows, often in societies, in the sides of hills, banks of +rivers and nullas, and very often in the dams of tanks, and in old mud +walls, etc. In some parts of the country they are very destructive to +various crops, potatoes, carrots, and other vegetables. They never issue +forth till after dark, but now and then one will be found returning +to his lair in daylight. Dogs take up the scent of the Porcupine very +keenly, and on the Nilghiris I have killed many by the aid of dogs, +tracking them to their dens. They charge backwards at their foes, +erecting their spines at the same time, and dogs generally get seriously +injured by their strong spines, which are sometimes driven deeply into +the assailant. The Porcupine is not bad eating,—the meat, which is white, +tasting something between pork and veal.” + +Besides these three large crested species of _Hystrix_, there are four or +five smaller species without nuchal crests occurring in North-East India +and in the Malay region, from Nipal to Borneo. + +Fossil species of _Hystrix_ occur in the Pleistocene and Pliocene of +India, and in Europe from the Upper Pliocene to the Middle Miocene, +being perhaps also represented in the French Phosphorites. Remains from +the Pliocene and Miocene of the United States have been referred to +this genus, and if rightly determined are of especial interest from a +distributional point of view. + +_Atherura._[406]—The Brush-tailed Porcupines are much smaller animals +than the last, characterised by their long tails tipped with bundles of +peculiar flattened spines. Of the three species two are found in the +Malay region and one in West Africa. A fossil species occurs in the +cavern-deposits of Madras. + +_Trichys._[407]—This genus contains but one Bornean species (_T. +guentheri_), externally very like an _Atherura_, but differing from the +members of that genus in many important cranial characters. + + +_Family_ CHINCHILLIDÆ. + +Terrestrial forms, with elongated hind limbs, bushy tails, very soft fur, +and complete clavicles. Jugal without an inferior angle, and extending +forwards to the lachrymal; palate contracted in front and deeply +emarginate behind; incisors short, and the molars divided by continuous +enamel-folds into transverse laminæ. Neotropical region. This family +includes only three existing species, divided into as many genera. + +_Chinchilla._[408]—In this genus the fore feet have five and the hind +four digits, the tail is long and bushy, and the auditory bullæ are +enormous, appearing on the top of the skull. The one species (_C. +lanigera_) is restricted to the alpine zones of the Andes from the north +of Peru to the south of Chili. It is a Squirrel-like Rodent, about 10 +inches in length, the tail somewhat exceeding 5 inches, and the ears very +large. Its fur is greatly valued on account of its extreme softness and +delicate gray colour. + +_Lagidium_[409] and _Lagostomus_.[410]—_Lagidium_ has four digits in +both fore and hind feet, and _Lagostomus_ three only in the hind feet, +and the auditory bullæ are much smaller than in the preceding genus. +_Lagidium_ has the same distribution as _Chinchilla_; while _Lagostomus_, +as represented by the Viscacha (_L. trichodactylus_), is found in the +Pampas from the Uruguay River to the Rio Negro. The Viscachas live in +burrows, generally in large numbers, and are nocturnal in their habits. +Remains referable to the existing species, as well as others which appear +to belong to extinct forms, occur in the Pleistocene deposits of South +America. + +_Extinct Genera._—Several Rodents from the South American Tertiaries +more or less closely allied to _Lagostomus_ have been described by Dr. +Ameghino under the names of _Prolagostomus_, _Pliolagostomus_, etc. +The huge _Megamys_ (_Potamarchus_), from the infra-Pampean deposits of +Parana and Patagonia, is referred to this family, and has dimensions +approximating to those of an Ox. Other fossil genera have received the +names of _Epiblema_ and _Tetrastylus_. + + +_Family_ CASTOROIDIDÆ. + +_Castoroides._[411]—The large Beaver-like Rodent with the dimensions of +a Bear from the Pleistocene of the United States described under this +name is regarded by Dr. Coues as the type of a family. Its dentition +is nearest to that of _Chinchilla_ and _Hydrochœrus_, but some of +the cranial characters are like those of the _Castoridæ_. The genera +_Amblyrhiza_ and _Loxomylus_, from the Pleistocene of the Antilles, +appear to be allied types. + + +_Family_ DASYPROCTIDÆ. + +Terrestrial forms with subequal limbs, hoof-like claws, short or obsolete +tail, and rudimentary clavicles. Mandibular masseteric ridge obsolete; +palate broad; incisors long; molars semi-rooted, with external and +internal enamel-folds. Neotropical region. + +_Dasyprocta._[412]—Includes several slender-limbed species, with three +hind toes, commonly called Agoutis, inhabiting Central and South America, +one (_D. cristata_) extending into the West-Indian Islands. Numerous +fossil remains of this genus occur in the cavern-deposits of Brazil. + +_Cælogenys._[413]—This genus is readily characterised by the presence +of five hind toes, and the extraordinary development of its zygomatic +arches, which are enormously expanded vertically, forming great convex +bony capsules on the sides of the face, enclosing on each side a large +cavity lined with mucous membrane, and communicating by a small opening +with the mouth. The Paca (_C. paca_) is about 2 feet long, and, like +the species of _Dasyprocta_, lives generally in the forests or along +the banks of rivers. This species appears to date from the epoch of the +Pleistocene deposits of the Brazilian caves. A smaller species from +Ecuador, living at elevations of from 6000 to 10,000 feet, has been +described as _C. taczanowskii_. + + +_Family_ DINOMYIDÆ. + +Distinguished from the _Dasyproctidæ_ by the cleft upper lip, rather +long and bushy tail, the presence of four digits in both fore and hind +feet, and the complete clavicles. The manubrium is broad; the optic +foramina are confluent; the incisors broad; and the molars rootless, with +enamel-folds dividing them into transverse laminæ. + +_Dinomys._[414]—The sole representative of this family is the Rodent +known as _D. branicki_, of which hitherto only a single specimen +has been obtained. This was captured in Peru, where it was found at +daybreak walking about a courtyard; the inhabitants of the district were +previously unacquainted with the species, from which its extreme rarity +may be inferred. Externally it resembles much the Paca, having similar +S-like nostrils; but in the laminated molars, and many features of the +skeleton, it differs from all the other Rodents with hoof-like nails. It +is regarded by its describer, the late Professor Peters, as a connecting +link between the _Octodontidæ_, _Chinchillidæ_, _Dasyproctidæ_, and +_Caviidæ_. + + +_Family_ CAVIIDÆ. + +Terrestrial or natatorial forms, with short incisors, strong mandibular +masseteric ridges, long and curved paroccipitals, and palate contracted +in front. Fore feet with four digits, hind feet with three. Clavicles +imperfect. Molars divided by enamel-folds into transverse laminæ; +milk-teeth shed before birth. Other characters as in _Dasyproctidæ_. +Neotropical region. + +_Cavia._[415]—Limbs and ears short, subequal; tail none. Vertebræ: C 7, D +13, L 6, S 4, C 7. This genus includes several species widely distributed +throughout South America, extending even to the Straits of Magellan. The +Restless Cavy (_C. porcellus_), which is found throughout Uruguay and +Brazil, has been very generally regarded as the ancestral form of the +domesticated Guinea-Pig. It is about 10 inches long, and weighs a little +over a pound; its fur is long and of a nearly uniform grayish-brown +colour. This species is rarely found in dry sandy localities, preferring +marshes covered with aquatic plants, among which it lies concealed, +feeding in the early morning and after sunset in the evening; but when +the soil is dry it forms burrows. It lives in societies of from six to +eighteen individuals, breeding but once a year, with one, or at most +only two, young at a birth. The Guinea-Pig (probably a misnomer of +Guiana-Pig) is larger than _C. porcellus_, and is regarded by Dr. Nehring +as descended from another species, _C. cutleri_. It is white in colour, +with irregular patches of reddish-brown and black. The Bolivian Cavy (_C. +boliviensis_), found throughout the higher regions of Bolivia, usually at +an elevation of 10,000 or 12,000 feet, is exceedingly shy, and lives in +burrows, which in some districts are so numerous as to have completely +undermined the soil. The Rock-Cavy (_C. rupestris_), distinguished by its +short, blunt nails, is found in rocky situations throughout Brazil, and +is much sought after for its flesh. The Southern Cavy (_C. australis_), +common along the coast of Patagonia, forms deep burrows, with several +outlets, in sandy declivities. Remains of existing species of _Cavia_ are +found in the cavern-deposits of Lagoa Santa, Brazil. + +_Dolichotis._[416]—Characterised by the great length of the ears and the +short tail. The palate is so much contracted in front that the premolars +of opposite sides touch by their antero-internal edges. Vertebræ: C 7, D +12, L 8, S 3, C 10. + +The Patagonian Cavy (_D. patachonica_)—the only living representative of +the genus—is rather larger than a Hare, which it somewhat resembles in +external appearance. It inhabits the dry sterile districts of Patagonia +and La Plata, disappearing wherever the country becomes more humid. This +animal burrows in the earth, although in districts where the Viscacha is +found it is said to avail itself of the works of the latter. Unlike other +cavies, its eyes are protected from the glare of the sun by prominent +eyelashes. The body is covered with a long dense fur of a rusty colour. +Two young are produced at a birth. Three species of _Dolichotis_ have +been described from the Brazilian cave-deposits, one of which is probably +not really separable from the existing form. + +_Hydrochœrus._[417]—A large aquatic form with all the feet fully webbed; +the skull (Fig. 213, p. 481) large, with enormous paroccipital processes; +and the molars very complex, the third upper one having some twelve +transverse laminæ. Upper incisors grooved. Vertebræ: C 7, D 14, L 6, S 3, +C 8. + +The Capybara (_H. capybara_) is the largest existing Rodent, and the +only living representative of the genus. It is a bulky and stoutly built +animal, and attains a length of about 4 feet. The body is covered with +long and coarse hair, reddish-brown above and brownish-yellow beneath. +Capybaras are found over the whole of the eastern part of South America, +and to the westward range into Bolivia and Peru. They frequent the +borders of rivers and lakes, concealing themselves among reeds and other +water plants. Remains of _Hydrochœrus_ are found in the cavern-deposits +of Brazil, which are probably referable to the existing species; one +extinct species from the Pleistocene of Buenos Ayres is estimated to +have attained a length of 5 feet, while _H. magnus_ of the same deposits +was of still larger dimensions. The genus is also represented in the +Pleistocene of South Carolina and the infra-Pampean beds of Parana. + +_Extinct Genera._—A number of South American fossil Rodents have been +referred to extinct genera of _Caviidæ_. Thus _Plexochœrus_, from the +Tertiary of Argentina, differs from _Hydrochœrus_ in having only nine +laminæ in the last upper molar; _Cardiomys_, _Cardiatherium_, etc., from +the infra-Pampeans are also stated to be allied to _Hydrochœrus_, while +_Contracavia_, of the same deposits, is related to _Cavia_, but of larger +size. _Microcavia_, again, from the Pleistocene of Argentina, is regarded +as connecting _Cavia_ with _Dolichotis_. The Tertiary European genera +_Issiodoromys_ and _Nesocerodon_ are apparently referable to the present +family. + + +_Suborder_ DUPLICIDENTATA. + +Two pairs of incisors in the upper jaw (the second very small, and placed +directly behind the large first pair), the enamel of which extends +round to their posterior surfaces. At birth there are three pairs of +these incisors, but the outer one on each side is soon lost. Incisive +foramina large; and usually confluent; bony palate very narrow from +before backwards; no true alisphenoid canal; fibula ankylosed to the +tibia, and articulating with the calcaneum. Testes permanently external. +This suborder includes the Picas, Hares, and Rabbits, all of which are +strictly terrestrial. + + +_Family_ LAGOMYIDÆ. + +Complete clavicles, subequal limbs, no external tail, and short ears. +Skull depressed, frontals contracted and without postorbital processes; +_p_ ¹⁄₁ or ²⁄₂; molars rootless, with transverse enamel-folds. Palæarctic +and Nearctic. + +_Lagomys._[418]—Represented by about a dozen species of small +Guinea-Pig-like animals, inhabiting chiefly the mountainous parts of +Northern Asia (from 11,000 to 14,000 feet), one species only being known +from South-East Europe, and another from the Rocky Mountains. + +The Picas, or Tailless Hares, live in holes among the rocks of their +native mountains, and are agile and shy little creatures. The genus is +well represented through the upper and middle Tertiaries. It has been +proposed to separate those fossil forms with _p_ ²⁄₁ as _Myolagus_, and +those with _p_ ¹⁄₁ as _Titanomys_, but this seems scarcely advisable. + + +_Family_ LEPORIDÆ. + +Imperfect clavicles, elongated hind limbs, short recurved tail, and +long ears. Skull (Fig. 216) compressed, frontals with large wing-shaped +postorbital processes _p_ ³⁄₂; molars as in the _Lagomyidæ_. Cosmopolitan +(except Australasia). Vertebræ: C 7, D 12, L 7, S 4, C 13-15. + +[Illustration: FIG. 216.—Skull of Hare (_Lepus timidus_).] + +_Lepus._[419]—The single genus _Lepus_ includes about twenty species, +all of which resemble one another in general external characters. In all +the fore limbs have five and the hind only four digits, and the soles of +the feet are densely clothed with hairs similar to those covering the +legs; the inner surface of the cheeks is also hairy. Although the family +has such a wide distribution, the greater number of the species are +restricted to the Palæarctic and Nearctic regions, only a single species +(_L. brasiliensis_) extending into South America, where it has existed +since the date of the Pleistocene deposits of the Brazilian caves. + +The Common Hare (_L. timidus_[420]) may be taken as a typical example of +the genus, and is characterised by the great length of the ears and hind +limbs. It is found in all parts of Europe except the north of Russia, +the Scandinavian peninsula, and Ireland. Its fur is usually of a tawny +gray colour above and white beneath, with the upper surface of the short +tail and the tips of the ears black. The colour of the fur differs, +however, considerably in different latitudes and at different seasons of +the year; showing a tendency to become white during winter in northern +countries, while assuming a reddish-yellow hue in the more genial climate +of southern Europe. The Hare is a nocturnal animal, remaining during the +day on its “form,” as the slight depression is called which it makes in +the open field, usually among grass. + +[Illustration: FIG. 217.—The Common Hare (_Lepus timidus_).] + +The Mountain Hare (_L. variabilis_) is found throughout the northern part +of the Palæarctic region, ranging from Ireland in the west to Japan in +the east, and also occurring in several of the more southerly mountain +ranges, such as the Pyrenees, the Alps, and the Caucasus. It is smaller +than the common species, with a smaller and more rounded head, and +shorter ears, tail, and hind limbs. In cold climates the colour of the +whole animal changes in the winter to a pure white (as in Fig. 218), with +the exception of the tips of the ears, which remain black. In Ireland no +winter change of colour takes place. + +[Illustration: FIG. 218.—The Mountain Hare (_Lepus variabilis_).] + +The Rabbit (_L. cuniculus_), speaking of the wild race only, is +distinguished from the Hare externally by its smaller size, shorter ears +and feet, the absence or reduction of the black patch at the tip of +the ears so characteristic of the Hare, and by its grayer colour. The +skull is smaller and lighter, with a slenderer muzzle and a longer and +narrower palate. Besides these characters, however, the Rabbit is sharply +separated from the Hare by the fact that it brings forth its young naked, +blind, and helpless; to compensate for this, it digs a deep burrow in +the earth in which they are born and reared, while the young of the Hare +are born fully clothed with fur, and able to take care of themselves in +the “form” in which they are born. The weight of the Rabbit is from 2½ +to 3 lbs., although individuals perfectly wild have been recorded up to +more than 5 lbs. Its general habits are too well known to need a detailed +description here. It breeds from four to eight times a year, bringing +forth each time from three to eight young. Its period of gestation is +about thirty days, and it begins to breed when six months old. It attains +to an age of about seven or eight years. + +[Illustration: FIG. 219.—The Rabbit (_Lepus cuniculus_).] + +The geographical distribution of the Rabbit presents many most +interesting peculiarities. It is believed to be originally a native of +the western half of the Mediterranean basin only, and still abounds in +Spain, Sardinia, Southern Italy, Sicily, Greece, Tunis, and Algeria; and +many of the Islands adjoining these countries are quite overrun with +it. Thence it has spread, partly by man’s agency, northwards throughout +temperate Western Europe, increasing rapidly wherever it gains a footing; +and this extension is still going on, as is shown by the case of +Scotland, in which sixty years ago Rabbits were little known, while they +are now found in all suitable localities up to the extreme north. It has +also gained admittance into Ireland, and now abounds there as much as in +England. Out of Europe the same extension of range has been going on. In +New Zealand and Australia Rabbits, introduced either for profit or sport, +have increased to such an extent as to form one of the most serious +pests that the farmers have to contend against, as the climate and soil +seem to suit them perfectly, and their natural enemies are too few and +too lowly organised to keep their numbers within reasonable bounds. In +other cases Rabbits introduced into islands have become or remained +more or less distinct from their parent stock; thus the Rabbits both of +the Falkland Islands and of Jamaica still show traces of their descent +from domesticated varieties, and have never reverted to the ordinary +brownish-gray type. And again, as was pointed out by Mr. Darwin,[421] +the Rabbits in the island of Porto Santo, near Madeira, whose ancestors +were introduced from Spain in 1418 or 1419, have formed quite a distinct +diminutive race, barely half the bulk or weight of English Rabbits, and +differing in certain slight details of colour and habits. + + _Bibliography of Rodentia._—G. R. Waterhouse, “Observations + of the Rodentia,” _Mag. Nat. Hist._ iii. (1839); Id. _Ann. + Nat. Hist._ viii. and x. (1839-42); Id. “On the Geographical + Distribution of the Rodentia,” _Proc. Zool. Soc._ 1839, pp. + 162-174; Id. _Natural History of the Mammalia_, vol. ii. + “Rodentia” (1848); Gervais, _Dic. Univ. d’Hist. Nat._ xi. p. + 202 (1848); Brandt, “Untersuchungen über die craniologischen + Entwickelungsstufen und Classification der Nager der Jetzwelt,” + _Mém. de l’Acad. Impér. de St. Pétersbourg_ (1855); Lilljeborg, + _Systematisk Œfversight af de Gnagnde Däggdjuren_, Upsala, + 1866; Alston, “On the Classification of the Order _Glires_,” + _Proc. Zool. Soc._ 1876, pp. 61-98; Trouessart, “Catal. de + Rongeurs, Vivants et Fossiles,” _Bullet. Soc. d’Études Scient. + d’Angers_, 1880-1881; Coues and Allen, “Monographs of North + American Rodentia,” _United States Geol. Surv. of Territories_, + vol. xi. (1877); Winge, “Rodentia pa Lagos Santa, Brazil.” + _Mus. Lund._ vol. iii. (1887); various papers by Peters in + _Monatsber. Ak. Berlin_, and by Alston, Anderson, Blanford, + Dobson, Milne-Edwards, Thomas, and others, in _Proc. Zool. + Soc._, _Journ. Asiat. Soc. Beng._, _Ann. Mag. Nat. Hist._, etc. + + + + +CHAPTER XI + +THE ORDER CARNIVORA + + +Though the existing Carnivora as at present restricted[422] form a very +natural and well-defined order among the Mammalia, it is difficult to +find any important common diagnostic characters by which they can be +absolutely separated; so that, as in the case of so many other natural +groups, it is by the possession of a combination of various characters +that they must be distinguished. Thus they are all unguiculate, and never +have less than four well-developed toes on each foot, with nails more +or less pointed, rarely rudimentary or absent. The pollex and hallux +are never opposable to the other digits. They are regularly diphyodont +and heterodont, and their teeth are always rooted.[423] Their dentition +consists of small pointed incisors, usually three in number, on either +side of each jaw, of which the first is always the smallest and the third +the largest, the difference being most marked in the upper jaw; strong +conical, pointed, recurved canines; cheek-teeth variable, but generally, +especially in the anterior part of the series, more or less compressed, +pointed, and trenchant; if the crowns are flat and tuberculated they +are never complex or divided into lobes by deep inflexions of enamel. +The condyle of the lower jaw is a transversely placed half-cylinder +working in a deep glenoid fossa of corresponding form. The brain varies +much in relative size and form, but the hemispheres are never destitute +of well-marked convolutions (Fig. 23, p. 71). The stomach (Fig. 234) +is always simple and pyriform. The cæcum is either absent or short +and simple (Fig. 235), and the colon is not sacculated, or greatly +wider than the small intestine. Vesiculæ seminales are never present. +Cowper’s glands are present in some, absent in other groups. The uterus +is bicornuate. The mammæ are abdominal, and very variable in number. +The placenta is deciduate, and almost always zonary. The clavicle is +often entirely absent, and when present is never complete. The humerus +often has an entepicondylar foramen. The radius and ulna are distinct. +The scaphoid and lunar bones are united into one, and there is never +a distinct os centrale in the adult. The fibula is always a distinct +slender bone. + +Several of these characters are, however, not applicable to all the +members of the extinct group of Carnivores for which the name Creodonta +has been proposed, as will be noticed in the sequel. + +The large majority of the species composing this order subsist chiefly +upon some variety of animal food, though many are omnivorous, and some +few chiefly, though not entirely, vegetable eaters. The more typical +forms live altogether on recently killed warm-blooded animals, and their +whole organisation is thoroughly adapted to a predaceous mode of life. +In conformity with this manner of obtaining their subsistence they are +generally bold and savage in disposition, though some species are capable +of being domesticated, and when placed under favourable circumstances +for the development of such qualities exhibit a very high degree of +intelligence and fidelity. The existing representatives of the order +are naturally divided into two suborders, the members of the one being +the more typical, and mainly terrestrial in their mode of life; while +those of the other are aberrant, having the whole of their organisation +specially modified for living habitually in water. These are called +respectively the True, or Fissiped, and the Pinniped Carnivora. + + +_Suborder_ CARNIVORA VERA. + +[Illustration: FIG. 220.—Left upper carnassial teeth of Carnivora. I, +_Felis_; II, _Canis_; III, _Ursus_. 1, Anterior, 2, middle (paracone), +and 3, posterior (metacone) cusp of blade; 4, inner tubercle (protocone) +supported on distinct root; 5, inner cusp posterior in position, and +without distinct root, characteristic of the _Ursidæ_.] + +Generally adapted for terrestrial progression and mode of life, though +some may be partially aquatic in their habits. The fore limbs never have +the first digit, or the hind limbs the first and fifth digits, longer +than the others. Incisors ³⁄₃ on each side, with very rare exceptions. +Cerebral hemispheres more or less elongated; always with three or four +gyri on the outer surface forming arches above each other, the lowest +surrounding the Sylvian fissure. The molar series of teeth have not +the uniform characters of those of the Pinnipedia. There is always one +tooth in each jaw which is specially modified, and to which the name of +“sectorial” or “carnassial” tooth has been applied. The teeth in front of +this are more or less sharp pointed and compressed; while those behind +it are broad and tuberculated. The characters of the carnassial teeth +deserve special attention, as, though fundamentally the same throughout +the suborder, they are greatly modified in different genera. The upper +carnassial is the most posterior of the teeth which have predecessors, +and is therefore reckoned as the last premolar (_p_ ⁴⁄ of the typical +dentition). It consists essentially of a more or less compressed blade +supported on two roots and an inner tubercle supported by a distinct +root (see Fig. 220). The blade when fully developed has three cusps +or lobes (1, 2, and 3), but the anterior is always small, and often +absent. The middle lobe is conical, high, and pointed; the posterior +lobe has a compressed straight knife-like edge. The inner tubercle (4) +varies very much in extent, but is generally placed near the anterior +end of the blade, though sometimes it is median in position. In the +_Ursidæ_ alone both the inner tubercle and root are wanting, and there +is often a small internal and posterior cusp (5) without root. In this +aberrant family also the carnassial is relatively to the other teeth much +smaller than in the rest of the Carnivora. The lower carnassial (see +Fig. 221) is the most anterior of the teeth without predecessors in the +milk-series; it is therefore reckoned the first true molar (_m_ ¹⁄). It +has two roots supporting a crown, consisting when fully developed of a +compressed bilobed blade (1 and 2), a heel, or talon (4), and an inner +cusp (3). The lobes of the blade, of which the hinder (2) is the larger, +are separated by a notch, generally prolonged into a linear fissure. In +the most specialised Carnivora, as the _Felidæ_ (I), the blade alone +is developed, both talon and inner cusp being absent or rudimentary. In +others, as _Meles_ (V) and _Ursus_ (VI), the heel is greatly developed, +broad, and tuberculated. The blade in these cases is generally placed +obliquely, its flat or convex (outer) side looking forwards, so that the +two lobes are almost side by side, instead of anterior and posterior. The +inner cusp (3) is generally conical, pointed, and placed to the inner +side of the hinder lobe of the blade. The special characters of these +teeth are more disguised in the Sea Otter (_Latax_) than in any other +form, but even in it they can be traced. + +[Illustration: FIG. 221.—Left lower carnassial teeth of Carnivora. I, +_Felis_; II, _Canis_; III, _Herpestes_; IV, _Lutra_; V, _Meles_; VI, +_Ursus_. 1, Anterior lobe (paraconid) of blade; 2, posterior (protoconid) +lobe of blade; 3, inner cusp (metaconid); 4, talon (hypoconid). It will +be seen that the relative size of the two roots varies according to +the development of the portion of the crown they have respectively to +support.] + +The homology of the various parts of the Carnivorous carnassial with the +primitive tritubercular type (p. 30) is indicated in the figures. It may +be observed, however, that the anterior lobe of the three-lobed upper +carnassial is an element added on to the more primitive two-lobed type. +When the talon of the lower carnassial, as in _Canis_, consists of a +large outer and small inner cusp, the latter (not seen in the figure) is +the entoconid. + +The toes are nearly always armed with large, strong, curved, and +tolerably sharp claws, ensheathing the ungual phalanges, and held more +firmly in their places by broad laminæ of bone reflected over their +attached ends from the bases of the phalanges. In some forms, most +notably the _Felidæ_, these claws are retractile; that is to say, the +ungual phalanx, with the claw attached, folds back in the fore foot into +a sheath by the outer or ulnar side of the middle phalanx of the digit, +being retained in this position when the animal is at rest by a strong +elastic ligament. In the hind foot the ungual phalanx is retracted on +to the top, and not the side of the middle phalanx. By the action of +the deep flexor muscles, the ungual phalanges are straightened out, the +claws protruded from their sheath, and the soft “velvety” paw becomes +suddenly converted into a most formidable weapon of offence. The habitual +retraction of the claws preserves their points from wear in ordinary +progression. + +The skeleton of the Lion represented in Fig. 15 (p. 45) illustrates the +digitigrade mode of progression of the _Felidæ_, as well as the essential +characters of the bony framework of a typical Carnivore. + +The Fissipedal Carnivora were divided by Cuvier into two groups, +according to the position of the feet in walking,—the Plantigrada, +or those that place the whole of the soles to the ground, and the +Digitigrada, or those that walk only on the toes; and the difference +between these groups was considered of equal importance to that which +separated the Pinnigrada or Seals from both of them. The distinction is, +however, quite an artificial one, since every intermediate condition +exists between the extreme typical plantigrade gait of the Bears and the +truly digitigrade walk of the Cats and Dogs; in fact, the greater number +of the Carnivora belong to neither one form nor the other, but may be +called “subplantigrade”; often when at rest applying the whole of the +sole to the ground, but keeping the heel raised to a greater or less +extent when walking. + +An amended classification of the existing forms is into three distinct +sections, of which the Cats, the Dogs, and the Bears may be respectively +taken as representatives, and which are hence called Æluroidea, Cynoidea, +and Arctoidea. This division is founded mainly on characters exhibited +by the base of the skull, but is corroborated by the structure of other +parts.[424] The presence or absence of a bridge of bone, covering the +external carotid artery in a part of its course by the side of the +alisphenoid bone, and enclosing the “alisphenoid canal” (see Fig. 8, p. +38), a character to which the late Mr. H. N. Turner first drew attention, +might seem unimportant at first sight, but it is curiously constant +in certain groups, which we have other reasons, derived often from a +combination of less easily definable characters, to regard as natural. It +is therefore generally mentioned in the following family definitions. + +It must, however, be stated that while the arrangement is a convenient +one as regards the existing Carnivores, it will not hold good when the +fossil forms are included. Thus there is ample evidence to show that +the Dogs and Bears were formerly so intimately connected that in a +palæontological classification the _Canidæ_ cannot be satisfactorily +separated from the _Ursidæ_; while in another direction the _Canidæ_ were +closely allied to the ancestral _Viverridæ_. The most important objection +against this classification is, however, the apparent intimate connection +exhibited by fossil forms between the _Viverridæ_ and the _Mustelidæ_, +which, so far as the present evidence goes, tends to show that the latter +are derived from the former. If this be eventually fully proved, it would +seem to indicate that the Arctoidea are not a natural group; and that the +resemblances between the _Ursidæ_ and _Mustelidæ_ have been independently +acquired, in the course of the descent of the one family from a Canoid, +and of the other from a Viverroid stock. + + +_Section_ ÆLUROIDEA. + +[Illustration: FIG. 222.—Left side of the palatal aspect of the cranium +and mandible of the Suricate (_Suricata tetradactyla_). _c_, Carotid +foramen; _f_, fissure in floor of auditory meatus. From Mivart, _Proc. +Zool. Soc._ 1882, p. 184.] + +The Æluroidea or Cat-like Carnivores include the _Felidæ_, _Viverridæ_, +_Proteleidæ_, and _Hyænidæ_. The existing representatives of this section +present the following common features. Auditory bulla (Fig. 222) much +dilated, rounded smooth, thin-walled, and (except in the _Hyænidæ_) +divided into two chambers, by a septum. Bony auditory meatus short. +Paroccipital process applied to, and spread over the hinder part of the +bulla (Fig. 222). Mastoid process never very salient, and often obsolete. +Carotid canal (Fig. 8, p. 38, _car_) small, sometimes very inconspicuous. +Condyloid and glenoid foramina concealed or wanting. Cæcum small, rarely +absent. Os penis generally small and irregular (large in _Cryptoprocta_). +Cowper’s glands present; prostate distinctly lobed. Some details of the +anatomy of the soft parts will be found under the head of _Genetta_. + + +_Family_ FELIDÆ. + +In all the forms, both recent and fossil, which can be included in this +family the canines are strongly developed, there are never more than +one upper and two lower molars, and the three lower incisors are placed +in the same horizontal line. With one exception, the humerus has an +entepicondylar foramen. + +The following characters are common to all the existing members. True +molars reduced to one above and below, that of the upper jaw very small +and transversely extended. Only two inferior premolars. Upper carnassial +with three lobes to the blade; lower without talon or inner cusp. +Auditory bulla not externally constricted. No alisphenoid canal. Carotid +canal very minute. Digits 5-4. Dorsal vertebræ 13. + +[Illustration: FIG. 223.—Front view of skull of Lion (_Felis leo_).] + +_Felis._[425]—The whole structure of the animals of this genus exhibits +the Carnivorous type in its fullest perfection. Dentition: _i_ ³⁄₃, _c_ +¹⁄₁, _p_ ³⁄₂, _m_ ¹⁄₁; total 30. A distinctly cusped inner tubercle to +the upper carnassial. Claws completely retractile. The upper anterior +premolar (_p._ 2), always small, and may be absent without any other +modification in the dental or other structures. Such a variation should +not therefore be considered as of generic importance. Incisors very +small. Canines large, strong, slightly recurved, with trenchant edges and +sharp points, and placed wide apart (Fig. 223). Premolars compressed and +sharp pointed. The most posterior in the upper jaw (the carnassial), a +very large tooth, consisting of a subcompressed blade, divided into three +unequal lobes supported by two roots, with a very small inner tubercle +placed near the front end of the tooth and supported by a distinct root +(Fig. 220). The upper true molar a very small tubercular tooth placed +more or less transversely at the inner side of the hinder end of the +last. In the lower jaw the true molar (carnassial) reduced to the blade +alone, which is very large, trenchant, and much compressed, divided +into two subequal lobes. Occasionally it has a rudimentary talon, but +never an inner cusp. The skull is generally short and rounded, though +proportionally more elongated in the larger forms. The facial portion +is especially short and broad, and the zygomatic arches are very +wide and strong. The auditory bullæ are large, rounded, and smooth. +Vertebræ: C 7, D 13, L 7, S 3, C 13-29. Clavicles better developed +than in other Carnivora, but not articulating with either the scapulæ +or sternum. Limbs digitigrade. Anterior feet with five toes, the third +and fourth nearly equal and longest, the second slightly and the fifth +considerably shorter; the pollex still shorter, not reaching as far as +the metacarpo-phalangeal articulation of the second. Hind feet with +only four toes. The third and fourth the longest, the second and fifth +somewhat shorter and nearly equal; the hallux represented only by the +rudimentary metatarsal bone. The claws all very large, strongly curved, +compressed, very sharp, and exhibiting the retractile condition in the +highest degree. The tail varies greatly in length, being in some a mere +stump, in others nearly as long as the body. Ears of moderate size, more +or less triangular and pointed. Eyes rather large. Iris very mobile, and +with a pupillary aperture which contracts under the influence of light +in some species to a narrow vertical slit, in others to an oval, and in +some to a circular aperture. Tongue thickly covered with sharp-pointed, +recurved horny papillæ. Cæcum small and simple. + +As in structure so in habits, the Cats may be considered the most +specialised of all the Carnivora. All the known members of the genus +feed, in the natural state, almost exclusively on warm-blooded animals +which they have themselves killed. One Indian species (_F. viverrina_) +preys on fish and even (it is said) on freshwater molluscs. Unlike the +Dogs, they never associate in packs, and rarely hunt their prey in open +ground, but from some place of concealment wait until the unsuspecting +victim comes within reach, or with noiseless and stealthy tread, +crouching close to the ground for concealment, approach near enough to +make the fatal spring. In this manner they frequently attack and kill +animals considerably exceeding their own size. They are mostly nocturnal, +and the greater number, especially the smaller species, more or less +arboreal. None are aquatic, and all take to the water with reluctance, +though some may habitually haunt the banks of rivers or pools, because +they more easily obtain their prey in such situations. + +The numerous species of the genus are very widely diffused over the +greater part of the habitable world, though most abundant in the warm +latitudes of both hemispheres. No species are, however, found in the +Australian region, or in Madagascar. Although the Old-World and New-World +Cats (except perhaps the Northern Lynx) are all specifically distinct, +no common structural character has been pointed out by which the former +can be separated from the latter. On the contrary, most of the minor +groups into which the genus has been divided have representatives in both +hemispheres. + +Notwithstanding the considerable diversity in external appearance and +size between different members of this extensive genus, the structural +differences are but slight, and so variously combined in different +species that the numerous attempts hitherto made to subdivide it are all +unsatisfactory and artificial. The principal differences are to be found +in the form of the cranium, especially of the nasal and adjoining bones, +the completeness of the bony orbit posteriorly, the development of the +first upper premolar and of the inner tubercle of the upper carnassial, +the length of the tail, the form of the pupil, and the condition and +coloration of the fur, especially the presence or absence of tufts +or pencils of hair on the external ears. Writing in 1881 Professor +Mivart[426] gave the number of existing species of _Felis_ as 48, but +by Mr. Blanford’s reduction of the number of Indian species[427] the +list may now be diminished to some 41. The following account is chiefly +devoted to some of the more important and better known species. + +A. _Old World Species._—The Lion (_F. leo_, Fig. 224) has been well known +to man from the earliest historic times. Its geographical habitat made it +familiar to all the races among whom human civilisation took its origin, +and its strongly marked physical and moral characteristics have rendered +it proverbial, perhaps to an exaggerated degree, and have in all ages +afforded favourite types for poetry, art, and heraldry. The literature +of the ancient Hebrews abounds in allusions to the Lion; and the almost +incredible numbers that are stated to have been provided for exhibition +and destruction in the Roman amphitheatres (as many as six hundred on a +single occasion by Pompey, for example) show how abundant these animals +must have been within accessible distance of the capital of the world. + +The geographical range of the Lion was once far more extensive than at +present, even within the historic period covering the whole of Africa, +the south of Asia, including Syria, Arabia, Asia Minor, Persia, and the +greater part of Northern and Central India, and also the south-eastern +portion of Europe, as shown by the well-known story told by Herodotus of +the attacks by Lions on the Camels which carried the baggage of the army +of Xerxes on its march through the country of the Pæonians in Macedonia. +The very circumstantial account of that historian shows that the animal +in his time ranged through the country south of the Balkans, through +Roumania to the west of the River Carasu, and through Thessaly as far +south as the Gulf of Lepanto and the Isthmus of Corinth, having as its +western boundary the River Potamo and the Pindus mountains. The whole +of the evidence relating to the existence of Lions in Europe, and to +their retreat from that continent shortly before the commencement of the +Christian era, has been collected in the article on “_Felis spelæa_” in +Boyd Dawkins and Sandford’s _British Pleistocene Mammalia_ (1868). Fossil +remains attest a still wider range, as it is shown in the same work that +there is absolutely no osteological or dental character by which the +well-known Cave Lion (_F. spelæa_), so abundantly found in cave-deposits +of the Pleistocene age in Western Europe, can be distinguished from the +existing _F. leo_. + +[Illustration: FIG. 224.—Lion and Lioness, after a drawing by Wolf in +Elliot’s Monograph of the _Felidæ_.] + +At the present day the Lion is found in localities suitable to its +habits, and where not exterminated (as it probably was in Europe) by the +encroachments of man, throughout Africa from Algeria to the Cape Colony, +and in Mesopotamia, Persia, and some parts of the north-west of India. +According to Blanford,[428] Lions are still very numerous in the reedy +swamps bordering the Tigris and Euphrates, and also occur on the west +flanks of the Zagros mountains and the oak-clad ranges near Shiraz, to +which they are attracted by the immense herds of swine which feed on the +acorns. The Lion nowhere exists in the table-land of Persia, nor is it +found in Baluchistan. In India, where it is verging on extinction, it +appears now to be confined to parts of Kattywar and Rajputana, though +within the present century its range extended through the north-west part +of India, from Bahawalpur and Sind to at least the Jumna (about Delhi), +southward as far as Khandesh, and in Central India through the Saugor +and Narbada territories, Bundelkund, and as far east as Palamau. It was +extirpated in Harriana about 1824. One was killed at Rhyli, in the Dumaoh +district, Saugor and Narbada territories, so late as in the cold season +of 1847-48; and one was shot in 1810 near Kot-Deji, Sind.[429] + +The great variations in external characters which different Lions +present, especially in the colour and the amount of mane, has given rise +to the idea that there are several species, or at all events distinct +varieties peculiar to different localities. It was at one time supposed, +on the authority of Captain Walter Smee,[430] that the Lion of Gujerat +differed essentially from that of Africa in the absence of a mane, but +subsequent evidence has not supported this view, which was probably +founded upon young specimens having been mistaken for adults. Lions from +that district as well as from Babylonia, which have lived in the gardens +of the London Zoological Society, have had as fully developed manes as +any other of the species. Mr. F. C. Selous[431] has shown that in South +Africa the so-called Black-maned Lion and others with yellow scanty manes +are found, not only in the same locality, but even among individuals of +the same parentage. + +The Lion belongs to a well-defined group, containing the largest members +of the genus, and differing from the others in the well-marked character +that the anterior cornu of the hyoid arch is but little ossified, so that +this arch is connected with the cranium by a long ligament, instead of by +a continuous chain of bones, and by the less important one that the pupil +of the eye, when contracted, is a circular hole, instead of a vertical +slit as in the cat. The Lion agrees with the Tiger and the Leopard in +these respects, but differs from them in its uniform style of colouring, +and from all the other _Felidæ_ in the arrangement of its hairy covering; +thus the hair of the top of the head, chin, and neck, as far back as the +shoulder, is not only very much longer, but also differently disposed +from the hair elsewhere, being erect or directed forwards, and so +constituting the characteristic ornament called the mane. There is also a +tuft of elongated hairs at the end of the tail, one upon each elbow, and +in most lions a copious fringe along the middle line of the under surface +of the body, wanting, however, in some examples.[432] It must, however, +be observed that these characters are peculiar to the adults of the male +sex only, and that young lions show indications of the darker stripes and +mottlings so characteristic of the greater number of the members of the +genus. + +The usual colour of the adult is yellowish-brown, but it may vary from a +deep red or chestnut brown to an almost silver gray. The mane, as well as +the long hair of the other parts of the body, sometimes scarcely differs +from the general colour, but it is usually darker and not unfrequently +nearly black. The mane begins to grow when the animal is about three +years old, and is fully developed at five or six. + +In size the Lion is only equalled or exceeded by the Tiger among the +existing _Felidæ_; though both species present great variations, the +largest specimens of the latter appear to surpass the largest Lions. A +full-sized South African Lion, according to Selous, measures slightly +less than 10 feet from nose to tip of tail, following the curves of +the body. Harris gives 10 feet 6 inches, of which the tail occupies 3 +feet. The Lioness is about a foot less. The tongue, like that of the +other species of the genus, is long and flat, and remarkable for the +development of the papillæ of the anterior part of the dorsal surface, +which (except near the edge) are modified so as to resemble long, +compressed, recurved, horny spines or claws; these, near the middle line, +attaining the length of one-fifth of an inch. They give the part of the +tongue on which they occur the appearance and feel of a coarse rasp, and +serve the purpose of such an instrument in cleaning the flesh from the +bones of the animals on which the Lions feed. + +The habits of the Lion in a state of nature are fairly well known from +the united observations of numerous travellers and sportsmen who have +explored those districts of the African continent in which it is still +common. It lives chiefly in sandy plains and rocky places interspersed +with dense thorn-thickets, or frequents the low bushes and tall rank +grass and reeds that grow along the sides of streams and near the +springs where it lies in wait for the larger herbivorous animals on +which it feeds. Although it is occasionally seen abroad during the +day, especially in wild and desolate regions, where it is subject to +but little molestation, the night is, as in the case of so many other +predaceous animals, the period of its greatest activity. It is then that +its characteristic roar is chiefly heard, as thus graphically described +by Gordon Cumming:— + +“One of the most striking things connected with the Lion is his voice, +which is extremely grand and peculiarly striking. It consists at +times of a low, deep moaning, repeated five or six times, ending in +faintly audible sighs; at other times he startles the forest with loud, +deep-toned, solemn roars, repeated in quick succession, each increasing +in loudness to the third or fourth, when his voice dies away in five +or six low muffled sounds very much resembling distant thunder. At +times, and not unfrequently, a troop may be heard roaring in concert, +one assuming the lead, and two, three, or four more regularly taking +up their parts, like persons singing a catch. Like our Scottish stags +at the rutting season, they roar loudest in cold frosty nights; but on +no occasions are their voices to be heard in such perfection, or so +intensely powerful, as when two or three troops of strange Lions approach +a fountain to drink at the same time. When this occurs, every member +of each troop sounds a bold roar of defiance at the opposite parties; +and when one roars, all roar together, and each seems to vie with his +comrades in the intensity and power of his voice. The power and grandeur +of these nocturnal concerts are inconceivably striking and pleasing to +the hunter’s ear.” + +“The usual pace of a Lion,” C. J. Andersson[433] says, “is a walk, and, +though apparently rather slow, yet, from the great length of his body, he +is able to get over a good deal of ground in a short time. Occasionally +he trots, when his speed is not inconsiderable. His gallop—or rather +succession of bounds—is, for a short distance, very fast—nearly or quite +equal to that of a horse. Indeed, unless the steed has somewhat the start +when the beast charges, it will be puzzled to escape. Many instances +are on record of horsemen who have incautiously approached too near to +the Lion, prior to firing, who have been pulled down by him before they +could get out of harm’s way. Happily, however, the beast soon tires of +the exertion of galloping, and unless his first rush succeeds he, for +the most part, soon halts and beats a retreat.” “The Lion, as with other +members of the feline family,” the same writer tells us, “seldom attacks +his prey openly, unless compelled by extreme hunger. For the most part he +steals upon it in the manner of a cat, or ambushes himself near to the +water or a pathway frequented by game. At such times he lies crouched +upon his belly in a thicket until the animal approaches sufficiently +near, when, with one prodigious bound, he pounces upon it. In most cases +he is successful, but should his intended victim escape, as at times +happens, from his having miscalculated the distance, he may make a second +or even a third bound, which, however, usually prove fruitless, or he +returns disconcerted to his hiding-place, there to wait for another +opportunity.” His food consists of all the larger herbivorous animals of +the country in which he resides—buffaloes, antelopes, zebras, giraffes, +or even young elephants or rhinoceroses, though the adults of these +latter he dare not attack. In cultivated districts the cattle, sheep, +and even human inhabitants are never safe from his nocturnal ravages. +He appears, however, as a general rule, only to kill when hungry or +attacked, and not for the mere pleasure of killing, as with some other +carnivorous animals. Moreover, he by no means limits himself to animals +of his own killing, but, according to Selous, often prefers eating game +that has been killed by man, even when not very fresh, to taking the +trouble to catch an animal himself. All books of African travel and sport +abound with stories, many of which are apparently well authenticated, of +the lion’s prodigious strength, as, exemplified by his being able to drag +off a whole ox in his mouth to a long distance, even leaping fences and +dykes with it. + +The Lion appears to be monogamous, a single male and female continuing +attached to each other irrespectively of the pairing season. At all +events the Lion remains with the Lioness while the cubs are young and +helpless, and assists in providing her and them with food, and in +educating them in the art of providing for themselves. The number of cubs +at a birth is from two to four, usually three. They are said to remain +with their parents till they are about three years old. The following +account by an eye-witness gives a good idea of Lion family life[434]:— + +“I once had the pleasure of, unobserved myself, watching a lion family +feeding. I was encamped on the Black Umfolosi in Zululand, and towards +evening, walking out, about half a mile from camp, I saw a herd of zebra +galloping across me, and when they were nearly 200 yards off, I saw a +yellow body flash towards the leader, and saw him fall beneath the lion’s +weight. There was a tall tree about 60 yards from the place, and anxious +to see what went on, I stalked up to it, while the lion was still too +much occupied to look about him, and climbed up. He had by this time +quite killed the beautifully striped animal, but instead of proceeding +to eat it, he got up and roared vigorously, until there was an answer, +and in a few minutes a lioness, accompanied by four whelps, came trotting +up from the same direction as the zebra, which no doubt she had been to +drive towards her husband. They formed a fine picture as they all stood +round the carcase, the whelps tearing it and biting it, but unable to get +through the tough skin. Then the lion lay down, and the lioness driving +her offspring before her did the same four or five yards off, upon +which he got up, and, commencing to eat, had soon finished a hind leg, +retiring a few yards on one side as soon as he had done so. The lioness +came up next and tore the carcase to shreds, bolting huge mouthfuls, but +not objecting to the whelps eating us much as they could find. There was +a good deal of snarling and quarrelling among these young lions, and +occasionally a stand-up fight for a minute, but their mother did not take +any notice of them, except to give them a smart blow with her paw if +they got in her way.... There was now little left of the zebra but a few +bones, which hundreds of vultures were circling round waiting to pick, +while almost an equal number hopped awkwardly about on the ground within +50 or 60 yards of it, and the whole lion family walked quietly away, the +lioness leading, and the lion, often turning his head to see that they +were not followed, bringing up the rear.” + +Though not strictly gregarious, Lions appear to be sociable towards their +own species, and often are found in small troops, sometimes consisting of +a pair of old Lions, with their nearly full-grown cubs, but occasionally +of adults of the same sex; and there seems to be good evidence that +several Lions will associate together for the purpose of hunting upon +a preconcerted plan. As might be supposed, their natural ferocity and +powerful armature are sometimes turned upon one another; combats, often +mortal, occur among male Lions under the influence of jealousy; and +Andersson relates an instance of a quarrel between a hungry Lion and +Lioness over the carcase of an Antelope which they had just killed, and +which did not seem sufficient for the appetite of both, ending in the +Lion not only killing, but even devouring his mate. Old Lions, whose +teeth have become injured with constant wear, often become “man-eaters,” +finding their easiest means of obtaining a subsistence in lurking in +the neighbourhood of villages, and dashing into the tents at night and +carrying off one of the sleeping inmates. Lions differ from most of the +smaller _Felidæ_ in never climbing trees; indeed, as mentioned before, +they are rarely found in forests. + +With regard to the character of the Lion, those who have had +opportunities of observing it in its native haunts differ greatly. The +exaggerated accounts of early writers as to its courage, nobility, and +magnanimity have led to a reaction, which causes some modern authors +to speak of it in language quite the reverse, and to accuse it of +positive cowardice and all kinds of meanness. Livingstone goes so far +as to say, “Nothing that I ever learned of the lion could lead me to +attribute to it either the ferocious or noble character ascribed to +it elsewhere,” and he adds that its roar is not distinguishable from +that of the ostrich. Of course these different estimates depend to +a great extent upon the particular standard of the writer, and also +upon the circumstance that Lions, like other animals, undoubtedly show +considerable individual differences in character, and behave differently +under varying circumstances. They are certainly not so reckless as to be +entirely devoid of the instinct of self-preservation, and if one, perhaps +satiated with a good meal the night before, unexpectedly disturbed in the +daytime, will occasionally retreat when confronted, even by an unarmed +man, that is scarcely a reason for assigning cowardice as one of the +characteristics of the species. The latest authority, Selous, while never +denying the daring courage of the Lion when hungry or provoked, and +vindicating the awe-inspiring character of the roar of several Lions in +unison, when heard at close quarters, as the grandest sound in nature, +says with regard to its outward aspect:— + +“It has always appeared to me that the word ‘majestic’ is singularly +inapplicable to the lion in its wild state, as when seen by daylight +he always has a stealthy furtive look that entirely does away with the +idea of majesty. To look majestic a lion should hold his head high. This +he seldom does. When walking he holds it low, lower than the line of +his back, and it is only when he first becomes aware of the presence of +man that he sometimes raises his head and takes a look at the intruder, +usually lowering it immediately, and trotting away with a growl. When +at bay, standing with open mouth and glaring eyes, holding his head +low between his shoulders, and keeping up a continuous low growling, +twitching his tail the while from side to side, no animal can look more +unpleasant than a lion; but there is then nothing majestic or noble in +his appearance.” + +Notwithstanding this evidently truthful description of the animal when +seen under what may be called unfavourable circumstances, no one with an +eye for beauty can contemplate the form of a fine specimen of a Lion, +at all events in a state of repose, even though in the confinement of a +menagerie, without being impressed with the feeling that it is a grand +and noble-looking animal. + +The Tiger (_F. tigris_) is so closely related to the Lion that it is +chiefly by external characters that the two species are distinguished. +There are, however, slight distinctions in the proportionate size of the +lower teeth, the general form of the cranium, and the relative length of +the nasal bones and ascending processes of the maxillaries by which the +skull of the Lion and Tiger can be easily discriminated by the practised +observer. + +Although examples of both species present considerable variations in +size, and reliance cannot always be placed upon alleged dimensions, +especially when taken from skins stripped from the body, it seems well +ascertained that the length of the largest-sized Bengal Tiger may exceed +that of any Lion. According to Mr. W. T. Blanford,[435] adult males +measure from 5½ to 6½ feet from the nose to the root of the tail; the +tail itself measuring some 3 feet in length. Measured along the curves +of the head and back to the tip of the tail, males usually give a length +of from 9 to 10 feet, but some specimens reach to 12 feet. The female +is somewhat smaller, and has a lighter and narrower head. The Tiger +has no mane, but in old males the hair of the cheeks is rather long +and spreading. The ground colour of the upper and outer parts of the +head, body, limbs, and tail is a bright rufous fawn, and these parts +are beautifully marked with transverse stripes of a dark, almost black +colour. The markings vary much in different individuals, and even on the +two sides of the same individual. The under parts of the body, the inside +of the limbs, the cheeks, and a large spot over each eye are nearly +white. The Tigers which inhabit hotter regions, as Bengal and the south +Asiatic islands, have shorter and smoother hair, and are more richly +coloured and distinctly striped than those of Northern China and Siberia, +in which the fur is longer, softer, and lighter coloured. + +[Illustration: FIG. 225.—The Tiger (_Felis tigris_).] + +The Tiger is exclusively Asiatic, but has a very wide range in that +continent, having been found in almost all suitable localities south of +a line drawn from the river Euphrates, passing along the southern shores +of the Caspian and Sea of Aral by Lake Baikal to the Sea of Okhotsk. +Its most northern range is the territory of the Amur, its most southern +the islands of Sumatra, Java, and Bali. Westward it reaches to Turkish +Georgia and eastward to the island of Saghalin. It is absent, however, +from the great elevated plateau of Central Asia, nor does it inhabit +Ceylon, Borneo, or the other islands of the Indo-Malayan Archipelago, +except those above mentioned. Its absence from Ceylon leads Mr. Blanford +to conclude that the Tiger has only recently migrated into Southern India. + +The principal food of the Tiger in India is cattle, deer, wild hog, and +pea-fowl, and occasionally human beings. The regular “man-eater” is +generally an old Tiger whose vigour is passed, and whose teeth are worn +and defective; it takes up its abode in the neighbourhood of a village, +the population of which it finds an easier prey than the larger or +wilder animals named above. Though chiefly affecting grassy plains or +swamps, it is also found in forests, and seems to be fond of haunting the +neighbourhood of old ruins. As a rule, Tigers do not climb trees; but +when pressed by fear, as during an inundation, they have been known to +do so. They take to the water readily and are good swimmers. The Tigers +of the Sundarbans (Ganges delta) continually swim from one island to the +other to change their hunting-grounds for deer. The following extract on +the habits of the Tiger is taken from Sir J. Fayrer’s _Royal Tiger of +Bengal_ (1875):— + +“The tigress gives birth to from two to five, even six cubs; but three is +a frequent number. She is a most affectionate and attached mother, and +generally guards and trains her young with the most watchful solicitude. +They remain with her until nearly full grown, or about the second year, +when they are able to kill for themselves and begin life on their own +account. Whilst they remain with her she is peculiarly vicious and +aggressive, defending them with the greatest courage and energy, and +when robbed of them is terrible in her rage; but she has been known to +desert them when pressed, and even to eat them when starved. As soon +as they begin to require other food than her milk, she kills for them, +teaching them to do so for themselves by practising on small animals, +such as deer and young calves or pigs. At these times she is wanton and +extravagant in her cruelty, killing apparently for the gratification +of her ferocious and bloodthirsty nature, and perhaps to excite and +instruct the young ones, and it is not until they are thoroughly capable +of killing their own food that she separates from them. The young tigers +are far more destructive than the old. They will kill three or four +cows at a time, whilst the older and more experienced rarely kill more +than one, and this at intervals of from three or four days to a week. +For this purpose the tiger will leave its retreat in the dense jungle, +proceed to the neighbourhood of a village or gowrie, where cattle feed, +and during the night will steal on and strike down a bullock, drag it +into a secluded place, and then remain near the ‘marrie,’ or ‘kill,’ for +several days, until it has eaten it, when it will proceed in search of a +further supply, and, having found good hunting ground in the vicinity of +a village or gowrie, continue its ravages, destroying one or two cows or +buffaloes a week. It is very fond of the ordinary domestic cattle, which +in the plains of India are generally weak, half-starved, under-sized +creatures. One of these is easily struck down and carried or dragged off. +The smaller buffaloes are also easily disposed of; but the buffalo bulls, +and especially the wild ones, are formidable antagonists, and have often +been known to beat the Tiger off, and even to wound him seriously.” + +In many districts of India the number of Tigers has been very +considerably diminished of late years. In some other countries they +appear, however, to be on the increase; thus according to one of the +administration reports of Java laid before the Dutch Chambers, portions +of that island are being depopulated through Tigers. In 1882 the +population of a village in the south-west of the Bantam province was +removed and transferred to an island off the coast in consequence of the +trouble caused to the people by Tigers. These animals have now become +an intolerable pest in parts of the same province. The total population +is about 600,000, and, in 1887, sixty-one were killed by Tigers, and in +consequence of the dread existing among the people, it has been proposed +to deport the inhabitants of the villages most threatened to other parts +of the country where Tigers are not so common, and where they can pursue +their agricultural occupations with a greater degree of security. At +present they fear to go anywhere near the borders of the forest. The +people seem disinclined, or they lack the means and courage, to attack +and destroy their enemy, although considerable rewards are offered by +Government for the destruction of beasts of prey. In 1888 the reward for +killing a Royal Tiger was raised to two hundred florins. It appears also +that the immunity of the Tiger is in part due to superstition, for it is +considered wrong to kill one unless he attacks first or otherwise does +injury. + +The Leopard (_F. pardus_, Fig. 226), although belonging to the same +restricted group as the two preceding species, is distinguished from both +by its inferior size, and its coloration. The animal now commonly known +as the Leopard was called Pard (πάρδος and πάρδαλις) or Panther (πάνθηρ) +by the ancients. Leopard (_leo-pardus_) is a later term, originally +applied, it is believed, to the Cheeta or Hunting Leopard, upon the +supposition that it was a creature intermediate between the Lion and the +true Pard. If so it has been completely transferred to the more common +species, and though in this sense a perfectly unnecessary and unmeaning +term, has gradually superseded those by which this was originally known. +Pard, so commonly used by Elizabethan authors, is now nearly obsolete +in the English language, and Panther has either become synonymous with +Leopard, or is used vaguely for any similar large feline animal, even the +Puma of America. + +[Illustration: FIG. 226.—The Leopard (_Felis pardus_).] + +Owing to their extensive geographical range, and the great variations, +both in size, form, and coloration to which Leopards are subject, +zoologists have scarcely decided whether all the forms popularly referred +to this animal should be regarded as specifically alike, or whether they +should constitute several distinct species, but the prevailing opinion +is in favour of the former view. The attempts to separate a larger and +more robust variety, under the name of Panther, from a smaller and more +graceful form, to which the term Leopard might properly be restricted, +have failed, owing to the existence of intermediate conditions which +cannot be assigned definitely to either one or the other form.[436] The +most marked anatomical difference yet noted in different varieties of +leopard is in the length of the tail as compared with that of the body, +even the number of the caudal vertebræ showing variation, though within +what limits, and whether correlated with other characters, has not yet +been clearly ascertained. The fur of those specimens which inhabit the +most northern confines of its range of distribution, as North China, is +longer and softer, and the markings are consequently less distinct than +on those from more congenial climates, and the well-marked variation thus +produced has given rise to the idea of specific distinction. + +The size of different individuals, as before said, varies greatly, the +head and body usually measuring from 3½ to 4½ feet in length, and the +tail from 2½ to 3 feet, but specimens have been met with which fall short +of or exceed these limits. The ground colour of the fur varies from a +pale fawn to a rufous buff, graduating into a pure white on the under +parts and inside of the limbs. This is spotted over with dark brown or +black; the spots on the back and sides being arranged in rosettes or +broken rings, which vary greatly in size and distinctness in different +individuals, but are without the central spot seen in those of the +Jaguar. The spots on the under parts and limbs are simple and blacker +than those on the other parts of the body. The bases of the ears behind +are black, the tips buff. The upper side of the tail is buff, spotted +with broken rings like the back, its under surface white with simple +spots. The hair of the cubs is longer than that of the adults, its +ground colour less bright, and its spots less distinct. Perfectly black +Leopards, which, however, in certain lights show the characteristic +markings on the fur, are not uncommon. These appear to be examples of +melanism, occurring as individual variations, sometimes in one cub out +of a litter of which the rest are normally coloured, and therefore not +indicating a distinct race, much less a species. These are met with +chiefly in Southern Asia. We are not aware of any recorded case from +Africa, though there seems no reason why they should not occur. + +In habits the Leopard resembles the other large Cat-like animals, +yielding to none in the ferocity and bloodthirstiness of its disposition. +It is exceedingly quick and active in its movements, but seizes its +prey by waiting in ambush or stealthily approaching to within springing +distance, when it suddenly rushes upon it and tears it to the ground with +its powerful claws and teeth. It preys upon almost any animal it can +overcome, such as antelopes, deer, sheep, goats, monkeys, peafowls, and +is said to have a special liking for dogs. It not unfrequently attacks +human beings in India, chiefly children and old women, but instances have +been known of a Leopard becoming a regular “man-eater.” When favourable +opportunities occur, it often kills many more victims than it can devour +at once, apparently to gratify its propensity for killing, or only for +the sake of their fresh blood. It generally inhabits woody districts, +and can climb high trees with facility if necessary for its safety when +hunted, but usually lives on or near the ground, among rocks, bushes, and +roots and low branches of large trees. + +The present geographical range of the Leopard is very extensive, as it is +met with in various suitable localities, where not too much interfered +with by human cultivation, throughout the greater part of Africa from +Algeria to the Cape Colony, and through the whole of the South of Asia +from Palestine to China, including all India south of the Himalaya, +and the islands of Ceylon, Java, Sumatra, and Borneo. Fossil bones and +teeth, indistinguishable from those of existing Leopards, have been +found in cave-deposits of Pleistocene age in Spain, France, Germany, and +England. The evidence of the former existence of the Leopard in England +is described at length by Boyd Dawkins and Sanford in their _British +Pleistocene Mammalia_.[437] + +The Ounce, or Snow Leopard (_F. uncia_), inhabits the highlands of +Central Asia, from the lofty mountains of Tibet to the southern parts +of Siberia, at altitudes of from 9000 to 18,000 feet above the sea. +It is about the size of the common Leopard, but lighter in colour, +with longer fur, less distinct spots, and a long thick tail. Its skull +differs in shape from that of all the other _Felidæ_; the facial portion +being very broad, the nasal bones especially being wide and depressed, +and the zygomatic arches very strong and deep. The Clouded Tiger (_F. +nebulosa_[438]) is a beautifully marked species, with elongated head +and body, long tail, and rather short limbs. The canine teeth are +proportionally longer than in any existing member of the genus. It is +thoroughly arboreal, and is found in the forests of South-East Asia and +the islands of Sumatra, Java, Borneo, and Formosa. _F. serval_, the +Serval, from South Africa, is yellow with black spots, and has a short +tail and large ears. Numerous smaller species called Tiger Cats and Wild +Cats, of which the Oriental _F. marmorata_ (Fig. 227) is a good example, +are found throughout the warmer parts of Asia and Africa. The Wild Cat of +Europe, _F. catus_, still inhabits the mountainous and wooded parts of +Great Britain. + +[Illustration: FIG. 227.—The Marbled Cat (_Felis marmorata_). From +Blanford, _Mammalia of British India_, p. 74, after Elliot.] + +The Caffre Cat (_F. caffra_[439]), of Africa and Southern Asia, was the +species held in veneration by the ancient Egyptians, and immense numbers +of its mummified remains have recently been found in Egypt, whence they +have been imported in large quantities to this country for manure. This +species is generally regarded as the main ancestral stock from which the +European Domestic Cat has been derived; one of the arguments in support +of this opinion being that the whole of the sole of the hind foot of +_F. caffra_ is black, and that the same feature obtains in the darker +varieties of the Domestic Cat; while in _F. catus_ there are only spots +of black upon this portion of the limb. Remains of the Caffre Cat occur +in the Pleistocene cave-deposits at Gibraltar. The Indian _F. rubiginosa_ +is the smallest species of Cat. + +The Caracal or Persian Lynx (_F. caracal_) is an animal about the size +of a fox, of slender build, with a moderately long tail, reaching down +to the heels. It is of a uniform vinous or bright fulvous brown colour +above, and is paler, sometimes almost white, beneath. It is quite or +almost entirely unspotted. The tail has a black tip, and the ears are +black externally, long, upright, pointed, and surmounted by a pencil +of fine black hairs. It inhabits Central and North-West India, Persia, +Arabia, Syria, and the greater part of Africa. + +The true Lynxes comprise various species or varieties found in the +northern and temperate regions of both the Old and New World, all larger +than the true Wild Cats, with long limbs, short stumpy tail, ears tufted +at the tip, and pupil of the eye linear when contracted. Their fur is +generally long and soft, varying, however, according to season and +locality, and always longish upon the cheeks. Their colour is always +light brown or gray, and generally more or less spotted with a darker +shade. The naked pads of the feet are more or less covered by the hair +that grows between them. The skull and skeleton do not differ markedly +from those of the other cats, but the small anterior upper premolar tooth +found in many other species is usually wanting; and the lower carnassial +has a rudimental talon. Their habits are exactly those of the other Wild +Cats, and they are exceeded by none in the untameable savageness of their +disposition. They capture their prey in the same manner, either lying in +wait, or noiselessly stealing within reach, and then making a sudden rush +or spring upon it. Their food consists of any mammals or birds which they +can overpower. In inhabited countries they commit extensive ravages upon +sheep, lambs, and poultry. Lynxes generally frequent rocky places and +forests, being active climbers, and passing much of their time among the +branches of the trees. Their skins are of considerable commercial value. + +Zoologists are by no means agreed at present as to the specific +distinctions, if any really exist, between the various modifications +of this group. As many as eight species are sometimes recognised, four +belonging to the Old and four to the New World. The former are _F. +lynx_, of Scandinavia, Russia, Northern Asia, and till lately the forest +regions of Central Europe; though not an inhabitant of Britain during +the historic period, its remains have been found in cave-deposits of +Pleistocene age; _F. cervaria_, Siberia; _F. pardina_, Turkey, Greece, +Sicily, Sardinia, and Spain; and _F. isabellina_, Tibet. The American +varieties are _F. canadensis_, the most northern species, and _F. +rufa_, the American Wild Cat or Bay Lynx, extensively distributed from +the Atlantic to the Pacific throughout nearly the whole latitude of +the United States, but replaced in Texas and southern California by +_F. maculata_, and in northern Oregon and Washington territory by _F. +fasciata_. + +[Illustration: FIG. 228.—European Lynx (_Felis lynx_). From a drawing by +Wolf in Elliot’s _Monograph of the Felidæ_.] + +In both cases, as might be supposed, specimens obtained from the more +southern climates are shorter in their fur, more brightly coloured, +and more distinctly spotted than those from colder regions. When only +a few individuals of each most markedly different form are examined +the distinctions are sufficiently evident. The occurrence, however, +of transitional or intermediate forms makes it extremely difficult to +draw the line between the different varieties or species, or to assign +definite characters by which they can be separated. Wherefore it is best +at present to accept the so-called species as only provisional, and wait +until more abundant materials, with fuller knowledge of the localities +from which they are derived, and of the variations due to age, sex, +season, and climate, have been more carefully studied. We shall then +probably come to the conclusion that all or nearly all the existing forms +of northern Lynxes, whether American or Eurasian, belong to what may +fairly be called a species, which is becoming by degrees differentiated +into several more or less strongly marked local varieties. Mr. W. T. +Blanford has indeed shown that the Tibetan Lynx (_F. isabellina_) is +inseparable from _F. lynx_; the specimens from Gilgit being intermediate +in colour between the typical forms of the two races. On the other hand, +from the evidence of cranial characters, Professor Mivart is disposed to +regard _F. pardina_ as a valid species. + +[Illustration: FIG. 229.—The Puma (_Felis concolor_).] + +B. _New World Species._—The Puma or Couguar (_F. concolor_, Fig. 229), +commonly called “Panther” in the United States, is about the size of a +Leopard, but of an uniform brown colour. It usually measures from nose +to root of tail about 40 inches, the tail being rather more than half +that length. The head is rather small compared with that of other Cats +and has no mane. The ears are large and rounded. The tail is cylindrical, +with some bushy elongation of the hairs near the end, but not forming a +distinct tuft as in the Lion. The general colour of all the upper parts +and sides of the adult is a tawny yellowish-brown, sometimes having a +gray or silvery shade, but in some individuals dark or inclining to +red. The lower parts of the body, inner surface of the limbs, the +throat, chin, and upper lip are dirty white; the outside of the ears, +particularly at their base, and a patch on each side of the muzzle black; +the end of the tail dusky. The young are, when born, spotted with dusky +brown and the tail ringed; these markings gradually fading, and quite +disappearing before the animal becomes full-grown. + +The Puma has an exceedingly wide range of geographical distribution, +extending over a hundred degrees of latitude, from Canada in the north +to Patagonia in the south, and was formerly pretty generally diffused +in suitable localities from the Atlantic to the Pacific Ocean, but the +advances of civilisation have in recent years considerably curtailed +the extent of the districts which it inhabits. In Central America it is +still common in the dense forests which clothe the mountain ranges as +high as 8000 or 9000 feet above the sea-level, where the hideous sound +of its howling is said to be almost continuously heard at night during +the breeding season. Though an expert climber, it is by no means confined +to wooded districts, being frequently found in scrub and reeds along the +banks of rivers, and even in the open pampas and prairies. Its habits +much resemble those of the rest of the group to which it belongs; and, +like the Leopard, when it happens to come within reach of an abundant +and easy prey, as the sheep or calves of an outlying farming station, it +kills far more than it can eat, either for the sake of the blood only +or to gratify its propensity for destruction. It rarely attacks man, +and, when pursued, escapes if possible by ascending lofty trees. Several +instances have occurred of Pumas becoming tame in captivity. Edmund Kean, +the celebrated actor, had one which followed him about like a dog. When +caressed they express their pleasure by purring like a domestic cat. + +_F. onca_, the Jaguar, is a larger and more powerful animal than the +last, and more resembles the Leopard in its colours. It also is found in +both North and South America, but with less extensive range, reaching +northwards only as far as Texas, and southwards nearly to Patagonia. +It climbs as well as the Puma, and preys to a great extent upon +monkeys. Several allied smaller elegantly spotted forms inhabiting the +intratropical regions of America are commonly included under the name +of Ocelot or Tiger Cat, though zoologists are still undecided whether +under this designation several distinct species have not been confused, +or whether all the Ocelots are to be referred to a single species (_F. +pardalis_) showing great individual or racial variation. Their fur has +always a tawny yellow or reddish-gray ground colour, and is marked with +black spots, aggregated in streaks and blotches, or in elongated rings +enclosing an area which is rather darker than the general ground colour. +They range through the wooded parts of tropical America, from Arkansas +in the north as far south as Paraguay, and in their habits resemble +the other smaller members of the Cat tribe, being ready climbers and +exceedingly bloodthirsty. + +_F. yaguarundi_, rather larger than the Domestic Cat, with an elongated +head and body, and of a uniform brownish-gray colour, ranges from +Matamoras to Paraguay. _F. eyra_ is a small Cat, very Musteline in form, +having an elongated head, body, and tail, and short limbs, and is also +of a uniform light reddish-brown colour. It is a native of South America +and Mexico. _F. pajeros_ is the Pampas Cat. The American Lynxes have been +already noticed with those of the Old World. + +[Illustration: FIG. 230.—The Ocelot (_Felis pardalis_).] + +C. _Fossil Species._—It has been already incidentally mentioned that +several of the existing species of _Felis_, such as the Lion, Leopard +and Caffre Cat, are met with in a fossil condition in the European +Pleistocene deposits, and it may be added that the Pardine Lynx has left +its remains in the cavern-deposits of Gibraltar. The caves of Brazil have +yielded remains of the Jaguar and Ocelot; while the Puma is found in the +Pleistocene of the United States. Existing species now inhabiting India +are met with in cavern-deposits in Madras. In the Pliocene Siwaliks of +Northern India the huge extinct _F. cristata_ shows characters connecting +it both with the Tiger and the Jaguar; and the same deposit also +contains the remains of a small species of the size of _F. bengalensis_. +In Europe numerous species occur in the Upper and Lower Pliocene, some +of which were as large as a Leopard. _F. atrox_ and _F. augusta_, of the +Pliocene of the United States, were of the dimensions of the Lion. + +_Cynælurus._[440]—The Cheeta or Hunting Leopard (_C. jubatus_) is +distinguished from the other _Felidæ_ by the inner tubercle of the upper +carnassial, though supported by a distinct root, having no salient cusp +upon it; by the tubercular molar being more in a line with the other +teeth; and by the claws being smaller, less curved, and less completely +retractile, owing to the feebler development of the elastic ligaments. +The skull is short and high, with the frontal region broad and elevated +in consequence of the large development of the frontal air-sinuses. The +head is small and round, the body light, the limbs and tail long. Its +colour is pale yellowish-brown with small black spots. The Cheeta is +less savage and more easily tamed than most of the Cats. In Asia it has +been trained for the chase of the Antelope. It has rather an extensive +geographical range from the Cape of Good Hope, throughout Africa and the +south-western parts of Asia, as far as Southern India. + +_Extinct Genera._—A number of forms are gradually becoming known, +especially through the researches of American palæontologists, which, +though evidently animals of the same general type, and therefore to be +placed in or near the family _Felidæ_, depart so much in various details +of structure that they must be referred to different genera. As one of +the points in which _Felis_ manifests its specialisation is the reduction +of the number of the molar series of teeth, with concomitant shortening +of the jaws, it might be supposed that in the earlier and perhaps +ancestral forms these teeth would be more numerous and approach more +nearly to the primitive or typical number of the heterodont mammals, viz. +seven on each side. This is actually the case. Similarly we find that +many of these forms exhibit a less specialised structure of the teeth +themselves, as is shown by the absence of the anterior lobe of the upper +carnassial, and the retention of the hind talon in the corresponding +lower tooth. Again, some of them have an alisphenoid canal in the skull; +while the femur may have a third trochanter, and the claws be very +imperfectly retractile. + +An extremely generalised form is the small _Proælurus_, from the Upper +Eocene and Lower Miocene, with _p_ ⁴⁄₄, _m_ ¹⁄₂, an alisphenoid canal, +and a third trochanter to the femur. _Dinictis_, of the North American +Miocene, is a larger allied form, with _p_ ³⁄₃, _m_ ¹⁄₂; the upper +carnassial having no anterior lobe, and the ungual phalanges being devoid +of bony sheaths. The characters of the base of the skull, and the form +and relations of the astragalus, differ very considerably from _Felis_. +_Pseudælurus_, from the French Miocene, is another very generalised +Feline, in which there may be either three or four premolars, and the +lower carnassial may retain its inner cusp. _Ælurictis_, of the French +Phosphorites, with _p_ ³⁄₃₋₄, _m_ ¹⁄₁₋₂, together with several American +Miocene genera, such as _Nimravus_ (_p_ ³⁄₂, _m_ ¹⁄₂), _Archælurus_ (_p_ +³⁄₃₋₄, _m_ ¹⁄₂), _Pogonodon_ (_p_ ³⁄₃, _m_ ¹⁄₁), and _Hoplophoneus_ (_p_ +²⁻³⁄₂, _m_ ¹⁄₁), approach more closely to the modern Cats, although many +or all of them retain the alisphenoid canal, and have not yet developed +the anterior lobe to the upper carnassial, or lost the talon to the lower +one. _Hoplophoneus_ has a descending flange to the mandible; and its +scapholunar bone has a line indicating its dual origin; while the femur +still retains the third trochanter, of which all traces are lost in the +modern Cats. + +On the other hand, some of the extinct _Felidæ_ show a most remarkable +tendency towards a specialisation not occurring in any of the surviving +members of the family, viz. an enormous development of the upper canines, +with which is usually associated an expansion downwards and flattening +of the anterior part of the ramus of the lower jaw, on the outer side +of which the canine lies, when the mouth is closed. In _Machærodus +næogeus_, the Sabre-toothed Tiger, from the caves of Brazil and also +from Pleistocene deposits near Buenos Ayres, an animal about the size +of a Tiger, these teeth are 7 inches in length, greatly compressed, and +finely serrated on the trenchant anterior edges. Similar serrations are +seen on a much fainter scale in the unworn teeth of modern Tigers. Many +modifications of this commonly-called “machærodont” type have been met +with both in the Old and New World. In _M. cultridens_, of the Upper +Pliocene of Italy and France, the upper canine is long and narrow, with +smooth cutting edges; the smaller form described as _M. meganthereon_ +being apparently the female of this species. _M. crenatidens_, of +the same deposits, is distinguished by the shorter and broader upper +canine, in which both edges are strongly serrated; the same feature +occurring in the closely allied or identical _M. latidens_ of the English +cavern-deposits. The Italian Pliocene form described as _M. nestianus_ +has serrations only on the hinder edge of the upper canine, and the third +lower premolar is separated by a long interval from the fourth. _M. +necator_, of the Pleistocene of South America, is remarkable as being +the only member of the family in which the humerus has no entepicondylar +foramen. A very remarkable form, _Eusmilus_, from the Upper Eocene +Phosphorites of Central France, differs from all other known Felines in +having only two pairs of incisors in the lower jaw, and a small canine +separated by a very long diastema from the cheek-teeth, which consist +only of one premolar and one sectorial true molar. The lower jaw is +enormously expanded towards the symphysis to protect the large upper +canines. This animal then, although of Eocene age, appears to form the +culminating development of the sabre-toothed or machærodont dentition, +the most specially carnivorous type of structure known. + +Other species of _Machærodus_ are found in the Pliocene deposits of +Europe and Asia. The accompanying woodcut exhibits the last two upper +teeth of the Indian _M. sivalensis_, from which it will be seen that the +inner tubercle of the carnassial is much reduced in size, while the molar +is very minute. + + +_Family_ VIVERRIDÆ. + +[Illustration: FIG. 231.—Oral surface of the left upper carnassial and +molar of _Machærodus sivalensis_.] + +Premolars ³⁄₃ or ⁴⁄₄. Molars ¹⁄₁ or ²⁄₂. Upper carnassial usually without +an anterior lobe, and the lower one with a well-developed talon; second +lower incisor (as in all the following families) raised above the level +of the first and third. Auditory bulla externally constricted, and +divided by a septum. An alisphenoid canal (with very rare exceptions). +Carotid canal distinct as a groove on the side of the bulla. Humerus +usually with an entepicondylar foramen. Digits usually 5-5, but sometimes +the pollex or hallux or both may be wanting. Dorsal vertebræ 13 or 14. +Limited in distribution to the Old World. + +The subfamily =Cryptoproctinæ= contains the single genus +_Cryptoprocta_.[441] Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ¹⁄₁; total +36. The teeth generally closely resemble those of the _Felidæ_. The first +premolar of both jaws is very minute and early deciduous. The upper +carnassial has a very small inner tubercle, quite at the anterior part +of the tooth. The true molar is very small and placed transversely. The +lower carnassial has a large trenchant bilobed blade, and a very minute +talon, but no inner cusp. Skull generally like that of _Felis_, but +proportionately longer and narrower. Orbit widely open behind. Vertebræ: +C 7, D 13, L 7, S 3, C 29. Body elongated. Limbs moderate in size. Feet +subplantigrade; five well-developed toes on each, with sharp, compressed, +retractile claws. Ears moderate. Tail long and cylindrical. + +The only known species, _C. ferox_, the “Foussa” of the Malagasy, is +peculiar to Madagascar, being the largest carnivorous animal in the +island. It is about twice the size of the common Cat (5 feet from nose +to end of tail), with short close fur of nearly uniform pale brown. +Little is as yet known of its habits, except that it is nocturnal, +frequently attacks and carries off goats, and especially kids, and shows +great ferocity when wounded, on which account it is much dreaded by the +natives. + +The remaining numerous specific and generic modifications found in the +existing animals belonging to this family seem to arrange themselves +mainly into two tolerably distinct groups, distinguishable by the +characters of the auditory bulla and neighbouring parts of the base of +the skull, and by the structure of the feet. The one form has the genus +_Viverra_ or Civet Cats for its most typical representative, and the +other _Herpestes_ or the Ichneumons. + +Subfamily =Viverrinæ=.—Auditory bulla oval, or rather conical, broad +and truncated and not everted behind, narrow in front and more or less +compressed at the sides. The outer or anterior chamber very small and +flat. The meatus with scarcely any inferior lip, its orifice being +close to the tympanic ring. Paroccipital process triangular, its apex +projecting slightly beyond the bulla. Claws strongly curved and more or +less retractile. Perineal scent-glands generally present. + +This subfamily includes both Ethiopian and Oriental forms, but the former +are the more numerous. + +The typical section, which includes five genera, has the following +characters. Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₂ (¹⁄₂ in +_Prionodon_); total 40. Skull elongated; facial portion small and +compressed. Orbits well-defined but incomplete behind. Teeth always +sectorial, never very small. Vertebræ: C 7, D 13, L 7 (or D 14, L 6), S +3, C 22-30. Body elongated and compressed. Head pointed in front; ears +rather small. Extremities short. Feet small and rounded. Toes short, five +on each foot. First toe both on fore and hind feet much shorter than the +others. Palms and soles covered with hair, except the pads of the feet +and toes, and in some species a narrow central line on the under side +of the sole, extending backwards nearly to the heel. Tail moderate or +long; usually marked with dark and light rings. A pair of large glandular +follicles situated on the perineum (in both sexes), and secreting in most +species an oily substance of a peculiarly penetrating odour. + +The numerous species of this section form a large series, the two +extremes of which differ considerably, but the several genera into which +they may be divided blend so into one another that it is difficult to +differentiate them sharply. + +All the animals of this section are, for their size, extremely active, +fierce, and rapacious. They feed chiefly on small mammals and birds. + +_Viverra._[442]—This includes the largest species. The teeth (Fig. 232) +are stouter and less compressed than in the other genera; the second +upper molar being especially larger. The auditory bulla smaller and more +pointed in front. Body shorter and stouter; limbs longer; tail shorter, +tapering. Under side of tarsus completely covered with hair. Claws +longer and less retractile. Fur rather long and loose, and in the middle +line of the neck and back usually elongated so as to form a sort of +crest or mane; neck with a black gorget. Pupil circular when contracted. +Perineal glands greatly developed. These characters apply especially +to _V. civetta_, the African Civet, or “Civet-Cat” as it is commonly +called, an animal rather larger than a common Fox, and an inhabitant of +intratropical Africa. _V. zibetha_, the Indian Civet, of about equal +size, inhabits Bengal, China, the Malay Peninsula, and adjoining islands. +_V. tangalunga_, from Java, Sumatra, Borneo, and the Philippines, and _V. +megaspila_, from Burma, are smaller but nearly allied animals; the latter +being more distinctly spotted than either of the others. From these +species and the next the civet of commerce, once so much admired as a +perfume in England, and still largely used in the East, is obtained. The +animals are kept in cages, and the odoriferous secretion collected from +the interior of the perineal follicles with a spoon or spatula. + +[Illustration: FIG. 232.—The left upper dentition of the Indian Civet +(_Viverra zibetha_). From the _Palæontologia Indica_.] + +The Rasse or Lesser Indian Civet (_V. malaccensis_) may be regarded as +the representative of a distinct group of _Viverra_, although often +referred to a separate genus (_Viverricula_). The size of this animal +is smaller than in the typical group, the build is slighter, the muzzle +finer, the claws sharper and more curved, and there is no erectile mane +along the back. Generally there is an alisphenoid canal in the skull; and +the anterior chamber of the auditory bulla is much more inflated than the +hinder one, so that the apparent length of the whole bulla is increased. +This species is found over the greater part of India, and extends to the +Malay Peninsula and Southern China. + +Large species of _Viverra_ occur in the Pleistocene and Pliocene of +India, and also in the Pliocene of France, which approximate in some +characters of the dentition to the extinct genus _Ictitherium_, mentioned +at the end of the family. Species of this genus have also been described +from the Miocene and Upper Eocene of Europe. The Lower Miocene _V. +antiqua_ has an alisphenoid canal, and all the other cranial characters +of the typical forms. + +_Fossa._[443]—The Fossa of Madagascar comes so close to the Rasse that +its right to generic distinction seems doubtful. There is, however, no +scent-pouch. The limbs are slender; and there are two small bare spots +on the sole of the hind foot, above the plantar pads. There is no dark +line along the back; the throat gorget of _Viverra_ is absent; and in the +tail the spots only tend to form rings, which are not complete. The skull +has an alisphenoid canal, and a large bulla as in the typical group of +_Viverra_. + +[Illustration: FIG. 233.—The Common Genet (_Genetta vulgaris_).] + +_Genetta._[444]—The Genettes are smaller animals, with more elongated +and slender bodies, and shorter limbs than the Civets. Skull elongated +and narrow. Auditory bulla large, elongated, rounded at both ends. Teeth +compressed and sharp pointed. The inner side of the third upper premolar +has a tubercle not present in the previous genus, and the talon of the +lower carnassial is larger. Pupil contracting to a linear aperture. Tail +long, slender. Fur short and soft, spotted or cloudy. Under side of the +tarso-metatarsus with a narrow longitudinal bald streak. No pouch for +storing the secretion of the scent-gland. _G. vulgaris_, the common +Genet (Fig. 233), is found in France south of the river Loire, Spain, +South-Western Asia, and Africa from Barbary to the Cape. _G. felina_, +_senegalensis_, _tigrina_, and _pardalis_ are other named species, all +African in habitat. + +[Illustration: FIG. 234.—Stomach of Genet cut open. _œ_, Œsophagus; _pv_, +pyloric valve; _x_, sudden bend where the internal folds are interrupted. +(From Mivart, _Proc. Zool. Soc._ 1882, p. 505.)] + +[Illustration: FIG. 235.—Cæcum of Genet. (After Mivart, _loc. cit._ p. +508.)] + +A few details (taken from Professor Mivart’s memoirs on the Æluroidea) of +the anatomy of the soft parts of the Genet may be given as illustration +of these parts in the Carnivora generally, and of this family and genus +in particular. The salivary glands are shown in Fig. 19 (p. 56), and +these conform to the general type prevalent in the Æluroidea. Thus +there is a distinct zygomatic gland; the parotid with its (Steno’s) +duct is well developed; and there is a small submaxillary gland. The +stomach (Fig. 234), while conforming to the simple type characteristic +of the Carnivora, is much larger than in the Cat; it is characterised +by the presence of some strongly marked internal folds near the pyloric +extremity, which stop suddenly at a point where the stomach makes an +abrupt constriction and flexure. Beyond this point there are three other +longitudinal folds; and the pyloric valve is small. The allied genera +present modifications from this form of stomach. The cæcum (Fig. 235) is +short, thick, and pointed. The liver (Fig. 236) much resembles that of +the Cat, but differs in that the left lateral lobe is undivided, although +having a small groove on its posterior or abdominal aspect, while the +cystic fissure is less deep, and situated more to the right. The caudate +lobe is relatively longer, has a deep concavity, and runs uninterruptedly +into the Spigelian; the latter being relatively somewhat larger than in +the Cat, with a deep groove dividing the proximal third from the distal +two-thirds. In _Viverra_ the right lateral and right central lobes are +nearly equal in size. The variations in the form of the liver of the +allied genera are detailed in Professor Mivart’s memoir. The brain of the +Genet is shown in Fig. 23 (p. 71); the small depression _d_ placed on +the superior lateral gyrus appears to be the sole representative of the +distinct crucial sulcus which distinguishes the brains of the _Felidæ_ +from those of all other members of the Æluroidea. + +[Illustration: FIG. 236.—Abdominal aspect of the liver of the Genet. _c_, +Caudal lobe; _gb_, gall-bladder; _ha_, hepatic artery; _hd_, hepatic +duct; _LC_, left central lobe; _LL_, left lateral lobe; _pv_, portal +vein; _RC_, right central lobe; _RL_, right lateral lobe; _Sp_, Spigelian +lobe; _vc_, vena cava. (From Mivart, _Proc. Zool. Soc._ 1882, p. 510.)] + +[Illustration: FIG. 237.—Cæcum of _Prionodon_. (From Mivart, _Proc. Zool. +Soc._ 1882, p. 508.)] + +_Prionodon._[445]—This and the following genus comprise the beautiful +Linsangs (Fig. 238), which are distinguished from the preceding genera +by the loss of the second upper molar, which is, however, very small in +some of the Genets. In the present genus the ground colour is whitish +or yellowish with brown or black markings, which may either form broad +continuous patches across the hinder part of the body, or may be broken +up into spots. The tail is very long, the limbs comparatively short, and +the fur very short and close. The pollex and hallux are well developed; +the claws are almost completely retractile; and the tarsus and metatarsus +are completely haired. The pupil is round. The cæcum (Fig. 237) is +remarkably small. This genus is exclusively Oriental, and comprises _P. +gracilis_ from Borneo, Java, and (?) Sumatra, _P. pardicolor_ from Nipal, +and _P. maculosus_ from Tenasserim; the head and body of the latter +measuring from 18 to 20 inches in length. Speaking of _P. pardicolor_, +Mr. Hodgson observes that it is “equally at home on trees and on the +ground; it dwells and breeds in the hollows of decayed trees. It is not +gregarious at all, and preys chiefly upon small birds, which it is wont +to pounce upon from the cover of the grass. The times of breeding are +said to be February and August, and the litter to consist of two young, +there being two litters each year.” + +_Poiana._[446]—This African genus, represented solely by one species, +_P. poënsis_ (Fig. 238), from Fernando Po, is very closely allied to +the preceding, but the spots are smaller, and show no tendency to run +into transverse bands or stripes, except in the region of the head and +shoulder; while the sole of the foot has a narrow bald band running up +towards the tarsus, as in _Genetta_. The length of the head and body is +38 inches, and that of the tail about 40 inches. It is probable that this +animal should really be regarded as a slightly aberrant species of the +genus _Prionodon_. + +[Illustration: FIG. 238.—The African Linsang (_Poiana poënsis_). From +Mivart, _Proc. Zool. Soc._ 1882, p. 160.] + +The five following genera differ in several important respects from all +the preceding, and collectively constitute the _Paradoxurine_ section +of Professor Mivart. With the exception of one African form, they are +mainly Oriental. In this section the auditory bulla is frequently in two +portions, the posterior moiety in one case being unossified, and it is +always much narrowed in front (Fig. 239). The palate (as in the figure) +may be much produced behind the molars; and the teeth are often but +slightly sectorial, and may be very small. The long tail is in most cases +not ringed. + +_Paradoxurus._[447]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₂; total +40. The blunt and rounded form of the cusps of the hinder premolar and +the molar teeth distinguishes this genus from most of the members of the +family. Vertebræ: C 7, D 13, L 7, S 3, C 29-36. Head pointed in front. +Ears small, rounded. Body long. Limbs moderate. Palms and soles almost +entirely naked, and joining the foot-pads without the intervention of +any hairy space. Claws completely retractile. Pupil vertical. Tail long, +non-prehensile; in the Indian species without rings. The Paradoxures +or Palm-Civets are less strictly carnivorous than the other members of +the family. They are mostly about the size of the common Cat, or rather +larger, and are partly arboreal in their habits. The species are rather +numerous, and present considerable variations in the details of the +form and size of their molar teeth; in only a few does the bony palate +extend behind the molars. They are restricted geographically to Southern +Asia and the Indo-Malayan archipelago. The best known species[448] are +_P. niger_, _P. hermaphroditus_, _P. jerdoni_, _P. aureus_, _P. grayi_ +from India and Burma, _P. philippinensis_ of the Philippines, _P. +larvatus_ of Southern China and Formosa, _P. leucomystax_ of the Malay +Peninsula, Sumatra, and Borneo, and _P. musschenbroeki_ of Celebes. The +name _Paradoxurus_ was applied from the mistaken notion that the tail +was prehensile. Mr. Blanford[449] gives the following account of the +habits of _P. niger_: “The common Palm-Civet, Tree-Cat, or Toddy-Cat, +is a familiar animal in most parts of India, though, being thoroughly +nocturnal in its habits, it is but rarely seen in the daytime. It is +arboreal, passing the day generally in trees, either coiled up in the +branches, or in a hole in the trunk, and in places where cocoa-nut +palms are common it frequently selects one of them for a residence. +Mango groves are also a favourite resort. It not unfrequently takes up +its abode in the thatched roofs of houses; Jerdon found a large colony +established in the rafters of his own house in Tellicheri. It even +occurs in large towns; I have known of one being caught in the middle of +Calcutta.” + +[Illustration: FIG. 239.—Palatal aspect of the left side of the +cranium and mandible of _Arctogale leucotis_. _a_, Anterior opening of +alisphenoid canal; _o_, foramen ovale; _c_, carotid canal ¹⁄₁. (From +Mivart, _Proc. Zool Soc._ 1882, p. 165.)] + +_Arctogale._[450]—This genus—represented only by _A. trivirgata_ of Java, +and _A. leucotis_ of Burma, Tenasserim, Sumatra, Java, etc.—is chiefly +distinguished from _Paradoxurus_ by the extremely small size of the +cheek-teeth (Fig. 239), which are often not in contact with one another; +the upper carnassial being almost triangular in shape. Palate frequently +convex longitudinally between the carnassials, and greatly produced +behind the last molar, with a very narrow bony aperture of the posterior +nares. The soles of the feet are still more naked than in _Paradoxurus_; +and the pollex and hallux are more divergent. In _A. leucotis_ the length +of the head and body is 26·5 inches, and the tail 27 inches. In many +specimens the three dorsal stripes are much less distinctly marked than +in others, and tend to break up into spots; while the general coloration +is considerably lighter. + +_Hemigale_,[451] another modification of the Paradoxure type, contains +one species, _H. hardwickei_, from Borneo and Malacca, an elegant-looking +animal, smaller and more slender than the Paradoxures, of light gray +colour, with transverse broad dark bands across the back and loins; +the proximal portion of the tail being ringed. The tarsus is hairy. The +general cranial characters are those of _Paradoxurus_, but the auditory +bulla is ankylosed into a single piece. + +_Arctictis._[452]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₂; total +40. The posterior upper molar and the first lower premolar very often +absent. Cheek-teeth generally small and rounded, with a distinct +interval between them, but formed generally on the same pattern as +_Paradoxurus_. Vertebræ: C 7, D 14, L 5, S 3, C 34. Body elongated. Head +broad behind, with a small pointed face. Whiskers long and numerous. Ears +small, rounded, but clothed with a pencil of long hairs. Eyes small. +Limbs short. Soles and palms broad, entirely naked. Tail very long and +prehensile; thickly covered with long hair. Fur long and harsh. Cæcum +extremely small. But one species is known, _A. binturong_, the Binturong, +an inhabitant of Southern Asia from Nipal through the Malay Peninsula to +the islands of Sumatra and Java. Although structurally agreeing closely +with the Paradoxures, its tufted ears, long, coarse, and dark hair, and +prehensile tail give it a very different external appearance. It may +be regarded as a very aberrant Paradoxure, connected, so far as dental +characters are concerned, with _Paradoxurus_ by means of _Arctogale_. The +bony palate also extends considerably behind the last molar, as in the +latter. The Binturong is slow and cautious in its movements, chiefly if +not entirely arboreal, and appears to feed on vegetable as well as animal +substances. + +_Nandinia_[453] contains one species, _N. binotata_, a somewhat aberrant +Paradoxure, from West Africa. It is rather smaller than the true +Paradoxures, with smaller and more pointed molar teeth, and no cæcum. The +wall of the hinder chamber of the auditory bulla remains through life +unossified. + +The dentition appears to be of a more decidedly carnivorous type than in +the other members of the section. + +_Cynogale._[454]—This remarkable genus is regarded by Professor Mivart as +representing a third section of the _Viverrinæ_; it contains one species, +_C. bennetti_ (described by S. Müller under the name of _Potamophilus +barbatus_), from Borneo, Sumatra, and the Malay Peninsula. This is a +curious Otter-like modification of the Viverrine type, having semiaquatic +habits, both swimming in the water and climbing trees, living upon fish, +crustacea, small mammals, birds, and fruit. The number and general +arrangement of its teeth are as in _Paradoxurus_, but the premolars are +peculiarly elongated, compressed, pointed and recurved, somewhat as in +the Seals, though the molars are tuberculated. The head is elongated, the +muzzle broad and depressed. Whiskers very long and abundant. Ears small +and rounded. Toes short and slightly webbed at the base. Tail short, +cylindrical, covered with short hair. Fur very dense and soft, of a dark +brown colour, mixed with black and gray. Humerus without entepicondylar +foramen. + +Subfamily =Herpestinæ=.—Auditory bulla very prominent, and somewhat +pear-shaped, the posterior chamber being large, rounded, and generally +with its greatest prominence to the outer side. The anterior chamber +considerably dilated, and produced into a short inferior wall to the +auditory meatus, in which is a depression or vacuity just below the +centre of the opening of the meatus. Sometimes this vacuity is continued +into the meatus, forming a narrow fissure. The paroccipital process +does not project beyond the bulla, but is spread out and lost (in adult +animals) on its posterior surface. Toes straight; claws lengthened, +exserted, non-retractile. No perineal glands. The dentition is always of +a markedly sectorial type; and the orbit may be surrounded by bone. Very +generally the anus opens into a sac-like depression. The majority of the +genera are Ethiopian; the type genus alone extending into the Oriental +and Palæarctic regions. + +_Herpestes._[455]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, sometimes ³⁄₃, +_m_ ²⁄₂; total 40 or 36. Teeth of molar series generally with strongly +developed, sharply-pointed cusps. Skull elongated, constricted behind +the orbits. Face short and compressed. Frontal region broad and arched. +Postorbital processes of frontal and jugal bones well developed, +generally meeting so as to complete the circle of the orbit behind. +Vertebræ: C 7, D 13, L 7, S 3, C 21-26. Head pointed in front. Ears short +and rounded. Body very long and slender. Extremities short. Five toes on +each foot, the first, especially that on the hind foot, very short. Toes +free, or but slightly palmated. Palms generally naked. Distal portion of +soles naked, under surface of tarsus and metatarsus usually clothed with +hair, but considerable specific variation in this respect. Tail long or +moderate, generally thick at the base, and sometimes covered with more or +less elongated hair. The longer hairs covering the body and tail almost +always annulated. This genus contains a very large number of animals +commonly called Ichneumons, or in India Mungooses, varying in size from +that of a large Cat down to a Weasel. They are widely distributed over +the African continent and the southern parts of Asia, especially India +and the Indo-Malayan archipelago, one species occurring also in Spain. +They are mostly terrestrial in their habits, feeding on small mammals +and birds, reptiles, especially snakes, eggs of birds and reptiles, and +also insects. Some species are partially domesticated, being used to +keep houses clear of rats, mice, and snakes. _H. ichneumon_ was a sacred +animal to the ancient Egyptians. They vary considerably in appearance, +some, as _H. galera_ and _H. urva_ (Fig. 240), are larger and heavier, +with stouter body, longer limbs, and stronger teeth. The common Indian +Mungoose (_H. mungo_) is considerably smaller than the Egyptian form; +its fur is of a pale gray colour, the hairs being largely white ringed, +while the cheeks and throat are more or less reddish. Like the Egyptian +species, it is frequently domesticated, and put to a similar use. It is +especially serviceable in India as a serpent-killer, destroying not only +the eggs and young of these creatures, but attacking without hesitation +and killing the most venomous adult snakes. The fact that it invariably +survives those encounters has led to the belief that it either enjoys +immunity from the effects of snake-poison, or that after being bitten +it has recourse, as the natives maintain, to the root of a plant as an +antidote. Neither of these suppositions has stood the test of scientific +examination, for it has been found that when actually bitten it falls +a victim to the poison as rapidly as other mammals, while there is no +trustworthy evidence of its seeking a vegetable antidote. The truth +seems to be that the Mungoose, by its exceeding agility and quickness +of eye, avoids the fangs of the snake while fixing its own teeth in +the back of the reptile’s neck. One large species, believed to be from +Africa, recently described as _H. grandis_, is remarkable for the extreme +complexity of the cusps on the molars, and also for the absence of an +entepicondylar foramen to the humerus; the latter feature also occurring +in the allied _H. albicaudatus_. The Oriental _H. urva_ (Fig. 246) is +stated to be somewhat aquatic in habits, and to feed on frogs and crabs. + +[Illustration: FIG. 240.—The Crab-eating Mungoose (_Herpestes urva_). +From Blanford, _Mammalia of British India_, p. 130.] + +Remains of the small _H. nipalensis_ occur in the cavern-deposits of +Madras. Viverroids from the Miocene and Upper Eocene of Europe, which +agree with _Herpestes_ in the presence of an inner tubercle to the +third upper premolar and of a hinder cusp to the fourth lower premolar, +have been referred to the existing genus. The species which have been +separated generically under the three following names are very closely +allied to _Herpestes_. + +_Helogale_,[456] premolars ³⁄₃, without diastema between first and +second; soles of feet completely naked. Contains two small South-African +species, _H. parvula_ and _H. undulata_. + +_Bdeogale_[457] contains also two small Ichneumon-like animals, _B. +crassicauda_ and _puisa_, differing from _Herpestes_ proper in having +only four toes on each foot, both pollex and hallux being absent. The +orbit is nearly complete, the tail of moderate length and rather bushy. + +_Cynictis._[458]—Pollex present, but hallux absent. Skull shorter and +broader than in _Herpestes_, rather contracted behind the orbits, which +are large and complete behind. Face short. Anterior chamber of the +auditory bulla very large. Front claws elongated. _C. penicillata_, from +South Africa. The cæcum (Fig. 241) of this genus is longer than in any +other member of the family. + +All the foregoing Herpestines have the nose short, with its under surface +flat, bald, and with a median longitudinal groove. The remaining forms +have the nose more or less produced, with its under side convex, and a +space between the nostrils and the upper lip covered with close adpressed +hairs, and without any median groove. + +[Illustration: FIG. 241.—Cæcum of _Cynictis penicillata_. (From Mivart, +_Proc. Zool. Soc._ 1882, p. 508.)] + +_Rhinogale._[459]—Toes 5-5. Claws of fore feet short, compressed, acute. +Under surface of tarsus hairy. Palate flat. Founded on a single specimen +from East Africa, _R. melleri_. + +_Crossarchus._[460]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ²⁄₂; total +36. Snout elongated. Toes 5-5. Claws on fore feet long and curved. +Hallux very short. Under surface of tarsus naked. Tail shorter than the +body, tapering. Palate flat. Fur harsh. Species: _C. obscurus_, the +Kusimanse, a small burrowing animal from West Africa, of uniform dark +brown colour; _C. fasciatus_; _C. zebra_; and _C. gambianus_. + +_Suricata._[461]—A more distinct genus than any of the above. The dental +formula as in the last, but the teeth of the cheek-series remarkably +short in the antero-posterior direction, corresponding with the shortness +of the skull generally (Fig. 222). Orbits complete behind. Vertebræ: C +7, D 15, L 6, S 3, C 20. Though the head is short and broad, the nose is +pointed and rather produced and movable. Ears very short. Body shorter +and limbs longer than in _Herpestes_. Toes 4-4, the pollex and hallux +being absent. Claws on fore feet very long and narrow, arched, pointed, +and subequal. Hind feet with much shorter claws, soles hairy. Tail rather +shorter than the body. One species only is known, the Suricate, _S. +tetradactyla_, a small gray-brown animal, with dark transverse stripes on +the hinder part of the back, from South Africa. The cæcum is short. + +[Illustration: FIG. 242.—Cæcum of _Galidea elegans_. (From Mivart, _Proc. +Zool. Soc._ 1882, p. 508.)] + +_Galidictis_,[462] _Galidea_,[463] and _Hemigalidea_[464] are names +of three slight generic modifications of the Viverrine type, allied +to the _Herpestinæ_, but placed by Mivart in a distinct subfamily, +_Galidictiinæ_. They are all characterised by the absence of the +alisphenoid canal in the skull, as well as of the entepicondylar foramen +to the humerus; and are inhabitants of Madagascar. The best known, +_Galidea elegans_, is a lively Squirrel-like little animal with soft fur +and a long bushy tail, which climbs and jumps with agility. It is of a +chestnut-brown colour, the tail being annulated with darker brown. The +cæcum (Fig. 242) is remarkable for its comparative length and pointed +termination. _Hemigalidea_ is distinguished by the absence of rings on +the tail. _Galidictis vittata_ and _striata_ chiefly differ from the +Ichneumons in their coloration, being gray with parallel longitudinal +stripes of dark brown. + +_Eupleres_[465] is another form, also from Madagascar, which has been +placed in a subfamily apart. It differs remarkably from all the other +_Viverridæ_ in the weak development of the jaws and the small size of the +teeth (Fig. 243), in consequence of which it was, when first discovered, +placed in the order Insectivora. Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, +_m_ ²⁄₂; total 40. Vertebræ: C 7, D 13, L 7, S 3, C 20. No alisphenoid +canal; an entepicondylar foramen to the humerus. But one species is +known, _E. goudoti_. + +[Illustration: FIG. 243.—Skull of _Eupleres goudoti_. ⅘ natural size. +Mus. Roy. Coll. Surgeons.] + +_Extinct Genera._—The Tertiaries of the Old World have yielded +several genera allied to the existing Viverroids, some of which show +decided signs of affinity with other families. Of these the Lower +Miocene _Amphictis_ appears to be nearly related to _Viverra_, but is +distinguished by the form of the second lower molar, which is longer and +has two distinct roots. _Palæoprionodon_, of the French Phosphorites, has +a dentition very like that of _Prionodon_, the molars being reduced to +¹⁄₂; the skull has an alisphenoid canal and the general basal characters +of the _Viverridæ_, but resembles the _Mustelidæ_ in the presence of +a glenoid foramen and in the position of the condylar foramen. In +_Stenoplesictis_, of the same deposits, the dental formula is _i_ ³⁄₃, +_c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₂; and although the skull has a complete septum +in the bulla, yet some of the cranial and dental features approximate +so decidedly towards those of the extinct _Mustelidæ_, as to lead +some authorities to refer the genus to that family. The most probable +explanation of this resemblance is that the Musteloids have originated +from generalised Viverroids allied to _Stenoplesictis_. The Lower +Pliocene _Ictitherium_ differs from all other Viverroids in the presence +of three distinct lobes to the upper carnassial, and thereby connects +the other members of the family so closely with the _Hyænidæ_ that it is +practically impossible to draw up a definition which will distinguish the +two families. + +The North American Eocene genera _Miacis_ and _Didymictis_ are generally +regarded as representing a separate family—_Miacidæ_—with affinities both +to the _Viverridæ_ and _Canidæ_. + + +_Family_ PROTELEIDÆ. + +Skull with no alisphenoid canal; and the auditory bulla divided into two +distinct chambers. Dorsal vertebræ 15. Molars ¹⁄₁. Premolar and molar +teeth very small and simple in character. + +_Proteles._[466]—This genus contains but a single species, _P. +cristatus_, the Aard-Wolf or Earth-Wolf of the Dutch colonists of the +Cape, an animal nearly allied to the Hyænas, but remarkably modified +in its dentition, the molar teeth being very small, placed far apart, +and almost rudimentary in character (Fig. 244). The canines are long +and rather slender. The dental formula is _i_ ³⁄₃, _c_ ¹⁄₁, _p_ and _m_ +⁴⁄₃₋₄; total 30 or 32. Vertebræ: C 7, D 15, L 5, S 2, C 24. The fore feet +with five toes; the pollex though short, with a distinct claw. The hind +feet with four subequal toes. Claws all strong, blunt, subcompressed, and +non-retractile. The general external appearance is very like that of a +small Striped Hyæna, but the muzzle is more pointed and the ears larger. +It has a copious mane of long hair, capable of being erected when the +animal is excited, along the middle line of the neck and back. It is a +native of South Africa, and is a burrowing nocturnal animal, feeding on +decomposing animal substances, larvæ, and termites. Observations upon +specimens in captivity indicate that it has neither inclination nor power +to attack or feed upon living vertebrated animals. + +[Illustration: FIG. 244.—Skull and Dentition of the Aard-Wolf (_Proteles +cristatus_). ½ natural size.] + +Some writers regard _Proteles_ as representing a subfamily of the +_Hyænidæ_.[467] + + +_Family_ HYÆNIDÆ. + +Skull with no alisphenoid canal; and the auditory bulla not divided by a +septum into two chambers. Dorsal vertebræ 15. Molars usually ¹⁄₁, but in +some fossil forms ¹⁄₂, or ²⁄₂, the second lower molar being very small; +upper carnassial with three distinct lobes; lower carnassial with a +large blade and small talon. No entepicondylar foramen to the humerus. +This family is confined to the Old World, where it is now represented +by a single genus, which, although evidently nearly related to the +_Viverridæ_, is sufficiently distinct to be regarded as not referable to +that family. The extinct _Ictitherium_, however, as already mentioned, +connects the more generalised members of the _Hyænidæ_ very closely with +the _Viverridæ_. + +_Hyæna._[468]—Dentition in existing forms usually _i_ ³⁄₃, _c_ ¹⁄₁, +_p_ ⁴⁄₃, _m_ ¹⁄₁; total 34. Teeth, especially canines and premolars, +very large, strong, and conical. Upper carnassial (Fig. 245) with a +very large, distinctly trilobed blade and a moderately developed inner +tubercle placed at the anterior extremity of the blade. Molar very +small, and placed transversely close to the hinder edge of the last, as +in the _Felidæ_. Lower carnassial consisting of little more than the +bilobed blade. Zygomatic arches of cranium very wide and strong. Sagittal +crest high, giving attachment to very powerful biting muscles. Orbits +incomplete behind. Vertebræ: C 7, D 15, L 5, S 4, C 19. Limbs rather +long, especially the anterior pair, digitigrade, four subequal toes on +each, with stout non-retractile claws. Pollex and hallux only represented +by rudimentary metacarpal and metatarsal bones. Tail rather short. A +large post-anal median glandular pouch, into which the largely developed +anal scent glands pour their secretion. + +[Illustration: FIG. 245.—Outer (_A_) and palatal (_B_) aspects of the +right upper carnassial tooth of the Striped Hyæna (_Hyæna striata_). From +the _Quart. Journ. Geol. Soc._] + +The three existing species of Hyæna are divisible into two sections, to +which some zoologists assign generic rank, but fossil forms show such +a transition between these two types as to render any such division +impracticable. + +The typical or _Euhyænine_ group presents the following distinctive +features. Upper molar moderately developed and three-rooted. An inner +cusp and hind talon more or less developed on the lower molar. Ears +large, pointed. Hair long, forming a mane on the back and shoulders. _H. +striata_, the Striped Hyæna (Fig. 246) of Northern Africa and Southern +Asia. _H. brunnea_, of South Africa, in some respects intermediate +between this and the next group. + +The Striped Hyæna is dirty gray in colour, with narrow transverse +tawny or blackish stripes on the body and legs; the length of the +head and body is 3½ feet, and that of the tail, with its hair, 1½ +feet. It occurs throughout peninsular India, where it is most common +in open hilly districts, and in North Africa. Mr. Blanford[469] gives +the following account of its habits: “It is a nocturnal animal, and +although an occasional individual may be met with returning to its den +in the early morning, its rambles are usually commenced after sunset +and ended before sunrise. During the night it roams far and wide, and +no tracks of wild animals are more common in the countries where it is +found than its unmistakable footprints, very like a dog’s in shape, but +with the marks of the hind feet conspicuously smaller than those of the +fore feet. Unlike the Spotted Hyæna, the Striped species appears to +be solitary in its habits, and it is rare to meet with more than two +together. The principal food of the Hyæna consists of the carcases of +animals that have died of disease or been killed by beasts of prey, and +very often it carries off portions of the body to its den. I once shot +one that was carrying away the hind leg of a Nilghai. The powerful jaws +and large teeth are admirably adapted for crushing bones, which are +consumed by Hyænas, after the flesh has been picked off by vultures and +jackals. Occasionally sheep or goats, and more often dogs, are carried +off by Hyænas, and the latter at all events are often taken alive to the +animal’s den.” The Striped Hyæna is essentially a cowardly animal, and +one that is much more silent than _H. crocuta_. Remains of _H. striata_ +are found in the cavern-deposits of the south of France, and also in the +Upper Pliocene of the Val d’Arno in Tuscany, and in the English Red Crag. + +[Illustration: FIG. 246.—The Striped Hyæna (_Hyæna striata_).] + +The _Crocutine_ group presents the following characters. Upper molar +extremely small, two- or one-rooted, often deciduous. Lower molar +without trace of inner cusp, and with an extremely small talon. Ears +moderate, rounded. Hair not elongated to form a mane. _H. crocuta_, the +Spotted Hyæna (Fig. 247), from Africa south of the Sahara. In dental +characters as well as in its visceral anatomy, especially as regards the +reproductive organs of the female,[470] this species may be considered +as by far the more specialised form. The Spotted Hyæna is a larger and +bolder animal than the Striped species, hunting in packs, and uttering +very frequently its unearthly cry. The coloration consists of dark brown +spots on a yellowish ground. It was formerly very common at the Cape. +Remains of a large race of this species are exceedingly common in the +cavern-deposits of Europe, where they were first described under the +name of _Hyæna spelæa_; teeth have also been met with in the Norfolk +Forest-bed, and in cavern-deposits in Madras—the latter locality being +exceedingly interesting from a distributional point of view. + +[Illustration: FIG. 247.—The Spotted Hyæna (_Hyæna crocuta_).] + +In addition to the remains of existing species, to which reference has +been already made, there were numerous extinct forms of _Hyæna_ in the +upper Tertiaries of Europe, from the horizon of the Lower Pliocene +Pikermi beds of Greece upwards. In the Crocutine group _H. colvini_ of +the Pliocene of India (Fig. 248), and _H. robusta_ of that of Italy, +appear to have been ancestral forms allied to _H. crocuta_; the former +being distinguished by the loss of the first upper premolar. _H. eximia_, +of the Pikermi beds, is a more generalised form, in which the first lower +premolar (lost in existing forms) is retained. In the typical group, _H. +arvernensis_ and _H. perrieri_, of the Upper Pliocene of the Continent, +approximate to _H. brunnea_; although _H. perrieri_ makes a farther step +towards the Crocutine group by the loss of the inner cusp in the lower +carnassial. The extinct _Hyænictine_ group, as represented by the Indian +_H. sivalensis_ and the Grecian _H. græca_, connects _H. striata_ with +_Palhyæna_. Both are characterised by the presence of a small second +lower molar behind the carnassial; while _H. græca_ also has four lower +premolars. Still more generalised is the _Lychyænine_ group; comprising +_H. macrostoma_ of India and _H. chæretis_ of the Pikermi beds; in these +forms the muzzle was longer, and the premolars much more compressed than +in the existing species, thus making a very decided approach to the +_Viverridæ_. There were four lower premolars; the lower carnassial had +an inner cusp, and it is probable that there was a second lower molar; +while the first upper molar was placed partially behind the carnassial. +The Lower Pliocene _Palhyæna hipparionum_, in which the dental formula +is _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₂, is a smaller form with long jaws +and compressed premolars which approaches so closely to the Viverroid +genus _Ictitherium_ as to show pretty clearly how the Hyænas have been +gradually modified from that stock. + +[Illustration: FIG. 248.—Outer view of part of the right ramus of the +mandible of _Hyæna colvini_, showing the third and fourth premolars and +the carnassial. (From the _Palæontologia Indica_.)] + + +_Section_ CYNOIDEA. + + +_Family_ CANIDÆ. + +This section contains the single family of the _Canidæ_, or Dog-like +animals, which appear to hold an intermediate position between the other +two sections, retaining also many of the more generalised characters of +the ancient members of the order. The structure of the auditory bulla and +adjacent parts of the bones of the skull is intermediate between that +of the Æluroid and Arctoid forms. In the number and arrangement of the +teeth they more nearly approach the primitive heterodont type than any +other existing Carnivora. A cæcum is always present, sometimes short and +simple, but when long it is folded upon itself in a characteristic manner. + +[Illustration: FIG. 249.—Right lateral aspect of the skull of the Dog +(_Canis familiaris_).] + +The characters of the base of the cranium are shown in Fig. 8 (p. 38), +where it will be seen that the auditory bulla is inflated, although +it has only a rudimental internal septum; the paroccipital process, +although in contact with the bulla, is prominent, and there is a large +glenoid foramen. In all the existing forms the humerus has lost the +entepicondylar foramen; the crowns of the upper molars are triangular in +shape (Fig. 251), and the blade of the upper carnassial consists of two +lobes. + +[Illustration: FIG. 250.—Cæcum of the Arctic Fox (_Canis lagopus_). _i_, +Ileum; _c_, colon. In the natural position the colon is uppermost.] + +In the alimentary canal the cæcum (Fig. 250) is extremely characteristic. +It is a simple appendage of nearly uniform width (about equal to that of +the ileum) attached to the side of the canal, just beyond the ileo-cæcal +valve, and with a rounded termination. In a Dog of average size it is 5 +or 6 inches long if uncoiled, but it is normally folded by its mesenteric +attachments backwards and forwards several times on itself by the side of +the ileum, after the manner shown in the figure. + +The existing Dogs form a very compact group, with numerous species +closely resembling each other in essential characters, though differing +considerably externally. The most marked differences are slight +variations in the number of the true molar teeth, which exceed the usual +number in the Cape Long-eared Fox (_Otocyon_), and fall short of it in +some other less aberrant forms to which the names of _Icticyon_ and +_Cyon_ have been given, and a diminution in the number of toes in the +Cape Hunting Dog (_Lycaon_), which has 4-4, instead of 5-4 as in the +remainder of the family. After taking these away, there remain a great +number of animals called Dogs, Wolves, Jackals, and Foxes, varying from +one another only in the characters of the tail, ears, fur, form of the +pupil, and some trifling peculiarities of skull and teeth, upon which +some authors have divided them into many genera. These divisions are, +however, extremely difficult, if not impossible, to define, on account of +the numerous gradual transitions from one form to the other. + +[Illustration: FIG. 251.—The last four left upper teeth of an extinct +Wolf (_Canis cautleyi_). From the _Palæontologia Indica_.] + +_Canis._[471]—It appears on the whole convenient to retain all the +species, with the exception of _Otocyon_, _Icticyon_, and _Lycaon_, in +the old genus _Canis_, the most prominent characters of which are the +following. Teeth, usually _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₃; total +42. The absence of the last upper molar (_m_ ³⁄), alone distinguishes +this from the generalised dentition of heterodonts, and this tooth is +occasionally present in one species (_C. cancrivorus_). In certain +Asiatic species (_C. primævus_ and its allies), which on this account +have been separated to form the genus _Cyon_ of Hodgson, the last lower +molar ⁄_m₃_ appears to be constantly absent. The milk-dentition is _di_ +³⁄₃, _dc_ ¹⁄₁, _dm_ ³⁄₃; total 28,—the first permanent premolar having no +predecessor. The teeth of both permanent and milk or temporary series are +figured on p. 26, Fig. 3, from the outer aspect, while the woodcut 251 +shows the palatal aspect of the hinder upper teeth. The upper carnassial +(_p_ ⁴⁄) consists of a stout blade, of which the anterior lobe is almost +obsolete, the middle lobe large, conical, and pointed backwards, and the +posterior lobe in the form of a compressed ridge; the inner tubercle is +very small, and placed quite at the fore part of the tooth. The first +molar is more than half the antero-posterior length of the carnassial, +and considerably wider than it is long; its crown consists of two +prominent conical cusps, of which the anterior is the larger, and a low +broad inward prolongation, supporting two more or less distinct cusps and +a raised inner border. The second molar resembles the first in general +form, but is considerably smaller. The lower carnassial ⁄_m₁_ is a very +large tooth, with a strong compressed bilobed blade, the hinder lobe +being considerably the larger and more pointed, a small but distinct +inner cusp placed at the hinder margin of the posterior lobe of the +blade, and a broad, low, tuberculated talon, or heel, occupying about +one-third of the whole length of the tooth. The second molar is less than +half the length of the first, with a pair of cusps placed side by side +anteriorly, and a less distinct posterior pair. The third is an extremely +small and simple tooth, with a subcircular tuberculated crown and single +root. + +The cranium (Fig. 249) is more or less elongated, the facial portion +tapering forwards and compressed. The jaws are elongated, and the +zygomata moderately strong. The postorbital processes of the frontal +short, leaving the orbit widely open posteriorly. Vertebræ: C 7, D 13, +L 7, S 3, C 17-22. Clavicles present, but very rudimentary. Limbs of +moderate proportions, digitigrade. Feet short; five toes on the fore +foot, the pollex much shorter than the others, and not reaching to the +ground. Four toes on the hind foot, the hallux being represented by a +rudiment of the metatarsal.[472] All the toes are provided with exserted, +non-retractile, slightly curved, and blunt claws, which, being exposed, +become worn at the tips. Tail moderate, or rather long, generally +somewhat bushy. The pupil of the eye, when contracted, is in some species +round, in others elliptical and vertical. + +This extensive genus may be considered as truly cosmopolitan. One or more +species occur in every part of the American continent from Greenland +to Patagonia and the Falkland Isles; and similarly, in the Old World, +Europe, Africa, and Asia, with most of the large islands adjacent, and +even Australia, have their wild Dogs, though in the last case they may +belong to a feral race, introduced originally by man. They are generally +sociable animals, hunting their prey in packs. Many species burrow in +the ground; none habitually climb trees. Though mostly carnivorous, +feeding chiefly on animals they have chased and killed themselves, many, +especially among the smaller species, eat garbage, carrion, insects, and +also fruit, berries, and other vegetable substances. The species are +very numerous, and, as in most other large genera, very ill-defined, +few zoologists agreeing as to which of the many slightly different +modifications should be considered as local varieties and which true +species. Perhaps the best cranial character by which the different +members of the genus can be distinguished is that pointed out by +Burmeister, viz. that in the animals generally called Dogs, Wolves, and +Jackals the postorbital process of the frontal bone is regularly smooth +and convex above, with its extremity bent downwards, whereas in Foxes +this process is hollowed above, with its outer margin (particularly of +the anterior border) somewhat raised. This modification coincides in the +main with that upon which Professor Huxley[473] has based his division +of the group into two parallel series, the Thooids or Lupine forms and +Alopecoids or Vulpine forms, which he characterises by the presence of +frontal air-sinuses in the former, which not only affect the external +contour but to a still greater degree the shape of the anterior part of +the cranial cavity, and the absence of such sinuses in the latter. The +pupil of the eye when contracted is round in most members of the first +group, and vertically elliptical in the others, but more observations are +required before this character can be absolutely relied upon. The form +and length of the tail is often used for the purposes of classification, +but its characters do not coincide with those of the cranium, since many +of the South American _Canidæ_ have the long bushy tails of Foxes and +the skulls of Wolves. Taking into account various combinations of these +and other minor characters, the species may be arranged in the following +groups, which some authors have considered as of generic importance. + +A. _Thooid or Lupine Series._—The typical group, or _Canis_ proper, +contains the largest members of the genus, the true Wolves of the +northern parts of both Old and New Worlds (_C. lupus_, etc.), the +Jackals of Southern Asia and Africa (_C. aureus_, _mesomelas_, etc.), +and the various breeds of the domestic Dog (_C. familiaris_). The true +Wolves are (excluding some varieties of the domestic Dog) the largest +members of the genus, and have a wide geographical range, extending over +nearly the whole of Europe and Asia, and North America from Greenland +to Mexico, but they are not found in South America or Africa, being +replaced in both of these continents by various species of Jackals and +Foxes. As might be expected from this extensive range, and the varied +character of the climatic conditions of the countries they inhabit, they +present great diversities of size, length and thickness of fur, and +coloration, although resembling each other in all important structural +characters. These differences have given rise to a supposed multiplicity +of species, expressed by the names of _C. lupus_, _C. lycaon_ (Central +Europe), _C. laniger_ and _C. niger_ (Tibet), _C. pallipes_ (India), _C. +occidentalis_, _C. nubilis_, _C. mexicanus_, etc., of North America, but +it is very doubtful whether some of these ought to be distinguished as +other than local varieties. Mr. W. T. Blanford, in his recent work on the +mammals of India, regards the two forms from Tibet mentioned above as +inseparable from _C. lupus_. In North America there is a very distinct +smaller species, called the Coyote or Prairie Wolf (_C. latrans_); +and perhaps the Japanese Wolf (_C. hodophylax_) may also be distinct, +although, except for its smaller size and shorter legs, it is scarcely +distinguishable from the common species. Though generally distributed +throughout the Indian peninsula, the Indian Wolf (_C. pallipes_), which +is rather smaller and slighter than _C. lupus_, is not found in Ceylon, +nor in Burma and Siam. The ordinary colour of the Common Wolf is a +yellowish or fulvous gray, but specimens have been met with almost pure +white and others entirely black. In northern countries the fur is longer +and thicker, and the animal generally larger and more powerful than in +the southern portion of its range; this being especially the case with +the Tibetan races. The habits of the Wolf are similar everywhere, and it +is still, and has been from time immemorial, especially known to man in +all the countries it inhabits as the devastator of his flocks of sheep. +They do not catch their prey by lying in ambush, or stealing up close to +it and making a sudden spring as the Cat tribe do, but by fairly running +it down in open chase, which their speed and remarkable endurance enable +them to do; and usually, except during summer, when the young families of +cubs are being separately provided for by their parents, they assemble in +troops or packs, and by their combined and persevering efforts are able +to overpower and kill even such great animals as the American Bison. It +is singular that such closely allied species as the Domestic Dog and the +Arctic Fox are among the favourite prey of Wolves, and, as is well known, +children and even full-grown people are not unfrequently the objects +of their attack when pressed by hunger. Notwithstanding the proverbial +ferocity of the Wolf in a wild state, many instances are recorded of +animals taken when quite young becoming perfectly tame and attached to +the person who has brought them up, when they exhibit many of the ways of +a Dog. They can, however, rarely be trusted by strangers. + +The history of the Wolf in the British Isles and its gradual extirpation +has been thoroughly investigated by Mr. J. E. Harting in his work on +_Extinct British Animals_, from which the following account is abridged: +To judge by the osteological remains which the researches of geologists +have brought to light, there was perhaps scarcely a county in England +or Wales in which, at one time or another, wolves did not abound, while +in Scotland and Ireland they must have been still more numerous. The +fossil remains which have been discovered in Britain are not larger +than, nor in any way to be distinguished from, those of European wolves +of the present day. Wolf-hunting was a favourite pursuit of the ancient +Britons as well as of the Anglo-Saxons. In Athelstan’s reign these +animals abounded to such an extent in Yorkshire that a retreat was +built by one Acehorn, at Flixton, near Filey, wherein travellers might +seek refuge if attacked by them. As is well known, great efforts were +made by King Edgar to reduce the number of wolves in the country, but, +notwithstanding the annual tribute of 300 skins paid to him during +several years by the king of Wales, he was not altogether so successful +as has been commonly imagined. In the reign of Henry III the number of +wolves in some parts of the country was sufficient to induce the king to +make grants of land to various individuals upon the express condition of +their taking measures to destroy these animals wherever they could be +found. In Edward II’s time the king’s forest of the Peak, in Derbyshire, +is especially mentioned as infested with wolves, and it was not until the +reign of Henry VII (1485-1509) that wolves appear to have become finally +extinct in England. This, however, is rather a matter of inference from +the cessation of all mention of them in local records than from any +definite evidence of their extirpation. Their last retreat was probably +in the desolate wolds of Yorkshire. In Scotland, as might be supposed +from the nature of the country, the wolf maintained its hold for a much +longer period. There is a well-known story of the last of the race being +killed by Sir Ewen Cameron of Lochiel in 1680, but there is evidence +of wolves having survived in Sutherlandshire and other parts into the +following century (perhaps as late as 1743), though the date of their +final extinction cannot be accurately fixed. In Ireland, in Cromwell’s +time, wolves were particularly troublesome, and said to be increasing in +numbers, so that special measures were taken for their destruction, such +as the offering of large rewards for their heads, and the prohibition +(in 1652) of the exportation of “wolf-dogs,” the large dogs used for +hunting the wolves. The active measures taken then and later reduced +their numbers greatly, so that towards the end of the century they became +scarce, but, as in the case of the sister island, the date of their final +disappearance cannot now be ascertained. It has been placed, upon the +evidence of somewhat doubtful traditions, as late as 1766. + +Remains of _C. lupus_ are common in the European Pleistocene; while the +Indian Pliocene _C. cautleyi_, of which the upper teeth are shown in Fig. +251, was probably the ancestor of _C. pallipes_. _C. neschersensis_, of +the Upper Pliocene of France, was a smaller extinct Wolf. A lower jaw +from the French Pleistocene, described under the name of _Lycorus_, has +only three premolars, but evidently belongs to the Wolf. + +The Jackals are smaller than the Wolves, with the bushy tail about +one-third the length of the head and body, and the carnassials relatively +shorter as compared with the tubercular molars. The Common Jackal +(_C. aureus_, Fig. 252) has a very wide distribution, ranging from +South-Eastern Europe through South-Western Asia to India and Burma, and +also occurring in Northern Africa; being replaced in the Ethiopian region +by closely allied species. Remains indistinguishable from _C. aureus_ +occur in the Pliocene Siwaliks of Northern India. Jackals hunt at night +in packs, uttering the piercing cries so well known to all who have +resided in countries where these animals are found. + +The origin of the Domestic Dog, with its numerous breeds, has been +the subject of much controversy. Some naturalists believe it to be a +distinct species, descended from one that no longer exists in a wild +state; others have sought to find its progenitors in some one of the wild +or feral races, either of true Dogs, Wolves, or Jackals; while others +again believe that it is derived from the mingling of two or more wild +species or races. It was probably the earliest animal domesticated by +man, and few if any other species have undergone such an extraordinary +amount of variation in size, form, and proportion of limbs, ears, and +tail—variations which have been perpetuated and increased by careful +selective breeding. The Dingo or Australian Dog is met with wild, and +also as the domestic companion of the aboriginal people. Dogs were also +in the possession of the natives of New Zealand and other islands of the +Pacific, where no placental mammals exist naturally, on their discovery +by Europeans in the last century. + +[Illustration: FIG. 252.—The Jackal (_Canis aureus_).] + +The second group includes the wild Dogs of the south-east of Asia, +described as _Cyon_, and distinguished by slight modifications as _C. +rutilans_, _C. dukhunensis_, and _C. javanicus_, and differing from the +above in wanting the small last lower tubercular molar. This difference +reduces the number of the teeth to the same as in _Viverra_, and +is precisely paralleled by some of the species of the extinct genus +_Cynodictis_ mentioned below. The muzzle is shorter than in other +species, and the facial profile is slightly convex instead of concave. +The mammæ are also 12 or 14 instead of the normal 10; while there is +long hair between the foot-pads. Wild Dogs inhabit not only the whole +of the Oriental region, but extend into Central Asia as far north as +the Altai and Amurland (_C. alpinus_). _C. dukhunensis_ ranges from the +forest regions of peninsular India to Gilgit and Western Tibet, where it +must inhabit open country. In their general form, and more especially +the shortness of the legs, these animals come nearer to the Jackals than +to the Wolves. They hunt their prey in packs. Remains of species of +this group occur in the cavern-deposits of the Continent, and have been +described under the name of _C. europæus_. + +A group for which the name _Lycalopex_ has been proposed comprises +certain South American _Canidæ_, distinguished from _Canis_ proper +by their longer tails and Fox-like aspect:—_C. cancrivorus_, _C. +brasiliensis_, _C. melampus_, _C. vetulus_, _C. fulvicaudus_, _C. +azaræ_, _C. magellanicus_, _C. griseus_. The last three have been +further separated (under the name of _Pseudalopex_) on account of slight +differences in the relative size of the molar teeth, and of their pupil +being elliptical when contracted. _Nyctereutes_ (one species, _C. +procyonides_, from Japan and North-East Asia) has no claims to generic +distinction but such as are founded upon its long loose fur, short ears, +and short bushy tail, which give it some superficial resemblance to a +Raccoon. + +B. _Alopecoid or Vulpine Series._—The _Vulpine_ group (_Vulpes_) includes +the true Foxes, of which there are numerous varieties and species, spread +over North America, Eurasia, and Africa, which have been described under +the names of _C. vulpes_ (_Vulpes alopex_), the common Fox of Europe; +_C. niloticus_, _adustus_, and _variegatus_, Africa; _C. flavescens_, +_montanus_, _bengalensis_, _japonicus_, _corsac_, Asia; _C. fulvus_, +_macrurus_, _velox_, North America. Mr. Blanford[474] concludes, however, +that the Asiatic _C. flavescens_ and _C. montanus_, and very probably +the North American Cross-Fox (_C. fulvus_) are merely local races of +_C. vulpes_, distinguished by certain peculiarities of coloration. The +English Fox measures about 2 feet in length exclusive of the tail, which +is about a foot long. Its fur is of a reddish-brown colour above, and +more or less white beneath; the back of the ears and the fore part of +the limbs are black, and the tip of its bushy tail is white. Its long, +sharp muzzle, erect pointed ears, and sharp eye, give it the well-known +appearance of sagacity and cunning. The Fox is a solitary animal, +inhabiting a burrow, which it either excavates for itself, or obtains by +ejecting the badger or the rabbit. So averse, indeed, is the Fox to dig +for itself, that when foiled in its attempts to dispossess the badger, +it has been known to take up its quarters with the latter, and it can be +induced to make its home in artificial burrows constructed of stone and +earth for the purpose of facilitating the operation of digging out the +cubs. The Fox also occurs in woods, and even in the open country without +burrows, lying in its “cover” by day and stealing forth at night in +search of its prey. Remains of the Common Fox occur not unfrequently in +the Pleistocene deposits of Europe. The Indian _C. bengalensis_ is a very +much smaller and well-marked species. + +The tail of the above forms is clothed with soft fur and long hair, +uniformly mixed; from them Baird distinguishes, under the name of +_Urocyon_, other species which have a concealed erect mane of stiff hairs +along the upper line of the tail. These have also a shorter muzzle and a +wide space between the temporal crests; they are _C. virginianus_ and _C. +littoralis_, both from North America. The Arctic Fox (_C. lagopus_, genus +_Leucocyon_, Gray) has the tail very full and bushy and the soles of the +feet densely furred below. Its colour changes according to season from +bluish-gray to pure white. + +Certain small elegant African Foxes (_C. zerda_, _famelicus_, and +_chama_), with very large ears and corresponding large auditory bullæ, +have been separated under the name of _Fennecus_, and are commonly known +as Fennecs. + +The earliest undoubted occurrence of the genus _Canis_ seems to be in the +Upper Miocene of Switzerland, where it is represented by the Fox-like _C. +œningensis_. In the Upper Pliocene of France _C. megamastoides_ is said +to be allied to the Foxes and Jackals, but with some signs of affinity to +the extinct _Cynodictis_. In the Pliocene Siwaliks of India there occurs +_C. curvipalatus_, of the size of a small Fox, which appears to have +certain resemblances to _Otocyon_. + +_Lycaon._[475]—This genus resembles in most of its characters the Dogs +of the Lupine series, but the teeth are rather more massive and rounded, +the skull is shorter and broader, and there are but four toes on each +limb, as in _Hyæna_. The one species, _L. pictus_, the Cape Hunting +Dog (Fig. 253) from South and East Africa, is very distinct externally +from all the other _Canidæ_. It is nearly as large as a Mastiff, with +large, broadly ovate erect ears, and singularly coloured, being not only +variable in different individuals, but unsymmetrically marked with large +spots of white, yellow, and black. It presents some curious superficial +resemblances to _Hyæna crocuta_, perhaps a case of mimetic analogy. +It hunts its prey in large packs. A lower jaw from a cave-deposit in +Glamorganshire, which agrees with that of the existing form in the +presence of an anterior cusp to the last lower premolar, has been made +the type of a distinct species (_L. anglicus_). + +_Icticyon._[476]—The Bush-Dog (_I. venaticus_), from Guiana and Brazil, +is a species about the size of a Fox, with close hair, and short legs and +tail, distinguished from all other Dogs by the reduction of the molar +teeth to ¹⁄₂, and their comparatively small size. The lower carnassial +is also characterised by the loss of the inner cusp of the blade, and +the secant form of its hind talon; both these features indicating a +specialised type. Remains of the Bush-Dog are found in the Pleistocene +cavern-deposits of Brazil, and were originally described under the name +of _Speothos_. + +[Illustration: FIG. 253.—The Cape Hunting Dog (_Lycaon pictus_).] + +_Otocyon._[477]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁻⁴⁄₄; total 46 +or 48. The molar teeth are thus in excess of any other living heterodont +mammal. They have the same general characters as in _Canis_, with +very pointed cusps. The lower carnassial shows little of its typical +characters, having five cusps on the surface; these can, however, be +identified as the inner cusp, the two greatly reduced and obliquely +placed lobes of the blade, and two cusps on the talon. The skull +generally resembles that of the smaller Foxes, particularly the Fennecs. +The auditory bullæ are very large. The hinder edge of the mandible has +a very peculiar form, owing to the great development of an expanded, +compressed, and somewhat inverted subangular process. Vertebræ: C 7, D +13, L 7, S 3, C 22. Ears very large. Limbs rather long. Toes 5-4. One +species, _O. megalotis_, from South Africa, rather smaller than a common +Fox. + +Professor Huxley looks upon this as the least differentiated or most +primitive existing form of the family, regarding the presence of the +four molar teeth as a survival of a condition of the dentition exhibited +by the common ancestors of the existing _Canidæ_ and the existing +carnivorous Marsupials. There is, however, at present no palæontological +proof of this, as none of the numerous fossil forms of _Canidæ_ yet +discovered have more than the normal number of molars. + +_Extinct Genera._—A large number of fossil Carnivora have been described +from various Tertiary deposits which are more or less closely allied to +the existing _Canidæ_, although, as already mentioned, connecting the +latter so closely on the one hand with the _Viverridæ_ and on the other +hand with the _Ursidæ_, that it is almost, if not quite impossible to +say where one family begins and the other ends. A few only of the more +important of these annectant types will be mentioned here. _Temnocyon_, +of the Miocene of the United States, is a true Dog, which agrees with +_Icticyon_ in having a secant hind talon to the lower carnassial, but +preserves a generalised character in having an entepicondylar foramen +to the humerus. An extremely interesting form is _Cynodictis_, of +the Middle Tertiaries of Europe and the United States, which (as now +restricted by Dr. Schlosser) includes a number of species mostly not +larger than Foxes. The dental formula is generally the same as in +_Canis_, but (as in that genus) the last lower molar may be absent. The +teeth are very like those of _Viverridæ_, the lower carnassial never +being greatly elongated antero-posteriorly, and its inner cusp being +situated immediately on the inner side of the hinder lobe of the blade, +instead of somewhat behind it, as is the case in most Dogs. In the +skull the auditory bulla is inflated, but is said to have no distinct +septum; while the humerus invariably has an entepicondylar foramen. It +is suggested that _Cynodictis_ is not far removed from the ancestral +type of many of the Viverroids and Canoids, and may itself have been +derived from the under-mentioned genus _Amphicyon_. M. Boule considers, +indeed, that from the resemblance of the Pliocene _Canis megamastoides_ +(p. 553) to _Cynodictis_ we ought to regard the Foxes and Jackals as the +descendants of _Cynodictis_, while the Wolves have been derived directly +from _Amphicyon_. The last named genus, which includes some species +as large as a Bear, is found in the Upper Eocene and Lower Miocene of +Europe, and is represented in the Miocene of the United States by the +allied _Daphœnus_. It is characterised by the presence of three upper +molars—thus bringing up the dental formula to the full Eutherian number; +by the five digits on all the feet, which were plantigrade; and by +the presence of a third trochanter to the femur and an entepicondylar +foramen to the humerus. The teeth are essentially those of a dog, and +the base of the skull is also dog-like, although it is highly probable +that the auditory bulla had no trace of a septum. According, however, to +Dr. Filhol[478] the minute foramina described by Professor Cope[479] in +the postparietal and mastoid which occur in _Ursus_, but are said to be +absent in _Canis_, are present in _Amphicyon_. So far, however, as we +can see, the presence or absence of those foramina cannot be regarded +as diagnostic of _Ursus_ and _Canis_, although they are generally more +strongly developed in the former. _Amphicyon_ may, indeed, be considered +as a very generalised Dog, with affinities to the Bears in the structure +of its limbs. _Dinocyon_ is a still larger form, from the Middle Miocene +of France, which, so far as its teeth are concerned, connects _Amphicyon_ +with the Ursoid genus _Hyænarctus_ so closely as to render it absolutely +impossible to indicate any characters of family importance by which they +can be distinguished. The upper carnassial of _Dinocyon_ is unknown. For +other genera, see p. 562. + + +_Section_ ARCTOIDEA. + +[Illustration: FIG. 254.—Right half of the palatal aspect of the cranium +of the Raccoon (_Procyon lotor_). Letters as in Fig. 8, p. 38. (From the +_Proc. Zool. Soc._ 1869, p. 10.)] + +This section includes a considerable number of forms which agree in the +essential characteristics of the structures of the base of the cranium +and reproductive organs, and in the absence of a cæcum to the intestinal +canal. They have no Cowper’s glands, but there is a rudimentary prostate +and a large cylindrical penial bone; while all the members of the group +have five completely developed toes on each foot. Considerable diversity +is found in the characters of the base of the skull in the various forms, +but the following features are common to all. The cavity of the auditory +bulla is simple, and has no trace of a dividing septum; the inferior lip +of the auditory meatus (_am_, Fig. 254) is considerably prolonged; the +paroccipital process (_p_) of the exoccipital is more or less triangular, +directed backwards, outwards, and downwards, and standing quite apart +from the bulla; the mastoid process (_m_) of the periotic is always +widely separated from the paroccipital, and generally very prominent; +the carotid foramen (_car_) is large, and placed on the inner margin of +the bulla, usually near the middle, but occasionally more posteriorly; +the condyloid foramen is distinct and exposed, and never sunk into a +common opening with the foramen lacerum posticum; and the glenoid foramen +is always present, and usually conspicuous. The alisphenoid canal is +absent except in _Ursus_, _Melursus_, and _Ælurus_. + +It has been already observed (p. 501) that the evidence of fossil forms, +so far as it goes, is not in favour of the Arctoidea being a natural +group; so that its retention must be regarded as a somewhat provisional +measure, largely based on its convenience. The group may be divided into +the three families, _Ursidæ_, _Procyonidæ_, and _Mustelidæ_.[480] + + +_Family_ URSIDÆ. + +In existing forms the true molars ²⁄₃, with broad, flat tuberculated +crowns. Typically the three anterior premolars of both jaws rudimentary +and often deciduous. Fourth upper premolar (carnassial) with no third or +inner root. An alisphenoid canal (except in _Æluropus_). Skull with the +auditory bulla depressed, and scarcely at all inflated. Feet plantigrade. +No entepicondylar foramen to the humerus. Kidneys conglomerate. +Geographical distribution extensive. + +_Ursus._[481]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₃; total 42. +The three anterior premolars above and below one-rooted, rudimentary, and +frequently wanting. Usually the first (placed close to the canine) is +present, and after a considerable interval the third, which is situated +close to the other teeth of the molar series. The second is very rarely +present in the adult state. The fourth (upper carnassial) differs +essentially from the corresponding tooth of other Carnivores in wanting +the inner tubercle supported by a distinct root. Its sectorial characters +are very slightly marked, and it is much smaller than the first molar. +The crowns of both the true molars are longer than broad, with flattened, +tuberculated, grinding surfaces. The second has a large backward +prolongation or heel. The lower carnassial has a small and indistinct +blade and greatly developed tubercular heel. The second molar is of +about the same length, but with a broader and more flattened tubercular +crown. The third is smaller. The milk-teeth are comparatively small, and +shed at an early age. Skull more or less elongated. Orbits small and +incomplete behind. Palate prolonged considerably behind the last molar +tooth. Vertebræ: C 7, D 14, L 6, S 5, C 8-10. Body heavy. Feet broad, +completely plantigrade; the five toes on each foot all well developed, +and armed with long compressed and moderately curved non-retractile +claws. Palms and soles naked. Tail very short. Ears moderate, erect, +rounded, hairy. Fur generally long, soft, and shaggy. + +[Illustration: FIG. 255.—Head of the Brown Bear (_Ursus arctos_). From +Sclater, _Proc. Zool. Soc._ 1867, p. 817.] + +The Bears are all animals of considerable bulk, and include among them +the largest members of the order. Though the species are not numerous, +they are widely spread over the earth’s surface (but absent from the +Ethiopian and Australian regions, and only represented by one species in +the Neotropical region), and differ much among themselves in their food +and manner of life. They are mostly omnivorous or vegetable feeders, and +even the Polar Bear, usually purely carnivorous or piscivorous, devours +grass with avidity in summer. The various species maybe arranged in the +following groups:— + +_Thalassarctine Group._—Head comparatively small, molar teeth small and +narrow. Soles more covered with hair than in the others. This group is +represented only by the well-known Polar or White Bear (_U. maritimus_) +of the Arctic regions, which is one of the few mammals which are +completely white at all seasons of the year. + +The typical, or _Ursine_, group includes a number of species, of which +the Common Brown Bear (_U. arctos_) is the best known example. This +species is an exceedingly variable one, and has a very wide range in +the Palæarctic region; the Syrian form described as _U. syriacus_, as +well as the Hairy-eared Bear (_U. piscator_, Fig. 255) of North-Eastern +Asia, and the Snow-Bear (_U. isabellinus_) of Kashmir and Nipal, not +being specifically separable. The Brown Bear hibernates in cold regions, +and in the Himalaya keeps to comparatively high regions, emerging +from its winter lair in March, April, or May, according to the season +and elevation, to feed on the numerous bulbous plants which abound in +the regions it inhabits. Both the Syrian and Himalayan varieties are +generally of lighter colour and smaller size than the typical European +form. Bears were at one time found in the British Isles, from which, +however, they have been long since exterminated. They are still found in +the Pyrenees, and are comparatively abundant in parts of Norway, Hungary, +and Russia. In the Kashmir Himalaya they were very abundant in some +districts a few years ago, one of the present writers having in 1874 seen +no less than seven examples at one time from the top of a mountain ridge; +of late years their numbers have, however, been greatly diminished. The +Brown Bear, although with strong powers of smelling, is very slow of +sight and hearing, and in the Himalaya it is easy to approach so near +that they may be shot with a smooth-bore gun. The Grizzly Bear (_U. +horribilis_) of North America is so closely allied to the Brown Bear +that some writers think it should only rank as a very well-marked local +variety. The Black Bears of the Himalaya (_U. torquatus_), Japan (_U. +japonicus_), and North America (_U. americanus_) belong to this group. +The Himalayan species ranges from Persia to Assam, and thence to China +and Formosa. In the greater part of this area it is essentially a forest +animal, and may be found in autumn in the forests of the Kashmir valley +feeding upon chestnuts and other fruits. It is also exceedingly fond +of maize, mulberries, and walnuts; and a few years ago it was no very +uncommon sight to see three or even five of these bears up a single +mulberry or walnut tree in Kashmir. The Spectacled Bear (_U. ornatus_) of +the Peruvian Andes is another member of this group. + +The _Helarctine_ group is represented only by the Malay Bear or Sun Bear +(_U. malayanus_), in which the head is short and broad; the molar teeth +are comparatively broad (but the length still exceeding the breadth), +the tongue is very long and extensile, and the fur short and smooth. +This small species inhabits the Malay Peninsula, Sumatra, Java, Borneo, +Tenasserim, Arakan, Chittagong, and the Garo hills of India; it inhabits +forest districts, and is an expert climber. + +The earliest known occurrence of the genus is in the Lower Pliocene of +the Indian Siwalik Hills; where it is represented by _U. theobaldi_, +which was probably the ancestor of the existing _Melursus_. The genus is +represented in the Upper Pliocene of Europe by the small _U. etruscus_; +and in the Pleistocene by the existing _U. arctos_, as well as by the +great extinct Cave-Bear (_U. spelæus_), distinguished by the complexity +of the crowns of the molars and the total loss of the three anterior +premolars in the adult condition. Remains of Bears are also found in +cavern-deposits in the north of Africa. The small _U. namadicus_, from +the Pleistocene of the Narbada valley, India, may have been allied to _U. +malayanus_. + +_Melursus._[482]—This differs from the true Bears in the first upper +incisor being absent or shed at a very early age, in the very small +size of the other teeth, in the very large extensile lips, the deep +concavity of the palate, and other minor characters. The one species, +_M. labiatus_, the well-known Sloth-Bear of India, feeds chiefly on +black ants, termites, beetles, fruit, honey, etc. This species inhabits +peninsular India, from near the Himalaya to Cape Comorin and Ceylon, and +its remains are found in the cavern-deposits of Madras. The black hair +is very long and coarse; there is a light horse-shoe-shaped mark on the +chest (as in _Ursus torquatus_), and the extremity of the muzzle is of an +ashy gray. + +[Illustration: FIG. 256.—_Æluropus melanoleucus._ (From Milne-Edwards.)] + +_Æluropus._[483]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₃, _m_ ²⁄₃; total 40. +Premolars large, increasing in size from first to last, and two-rooted +except the first. First upper molar with quadrate crown, broader than +long; second larger than the first. Cranium with zygomatic arches and +sagittal crest immensely developed, and ascending ramus of mandible +very high, giving greater spaces for attachments of temporal muscle +than in any other existing member of the order. Facial portion short. +Bony palate not extending behind the last molar tooth. No alisphenoid +canal. Feet bear-like, but soles more hairy, and perhaps less completely +plantigrade. Fur long and thick. Tail very short. One extremely rare +species, _A. melanoleucus_ (Fig. 256), discovered by Père David in 1869, +in the most inaccessible mountains of Moupin in Eastern Tibet. Said to +feed principally on roots, bamboos, and other vegetables. It is of the +size of a small Brown Bear, of a white colour, with ears, spots round the +eyes, shoulders and limbs black. In the large size and complex crowns of +the upper premolars this genus differs very markedly from the true Bears. +The fourth upper premolar (carnassial) makes no approach to the markedly +sectorial type presented by the corresponding tooth of _Hyænarctus_, its +structure being, on the whole, more like that of _Ælurus_. + +[Illustration: FIG. 257.—Palate of _Arctotherium bonariense_, +Pleistocene, South America—¼ natural size. (From the _Palæontologia +Indica_.)] + +_Extinct Genera._—The genus _Arctotherium_ includes some very large +Bear-like animals from the Pleistocene of South America and California, +in which the dentition departs less widely from a normal carnivorous +type than in the true Bears. Thus the upper carnassial (Fig. 257) is +relatively larger than in _Ursus_; while the crowns of the upper molars +are broader and shorter. The humerus is said to have an entepicondylar +foramen. _Hyænarctus_, of the Miocene and Pliocene of Europe and Southern +Asia, has the crowns of the upper molars either square or triangular; +the upper carnassial having three distinct lobes to the blade, while +the lower carnassial is practically indistinguishable from that of the +Dog-like _Dinocyon_ (p. 556). The proximal extremity of the ulna differs +from that of _Ursus_ in having a long olecranon, and thereby resembles +the corresponding bone of the Dogs. Indeed all the characters at present +available tend to show a complete passage from the Tertiary Dog-like +animals, through _Dinocyon_, _Hyænarctus_, and _Arctotherium_, to the +true Bears. Most of the species of _Hyænarctus_ were of very large +dimensions, but smaller forms occur in the Miocene. _Cephalogale_, of +the Continental Tertiaries, is a genus represented by several species +of medium size showing evident signs of affinity with _Hyænarctus_. The +upper molars have subtriangular crowns, while the carnassial is short, +and has two comparatively low lobes. Here also may be mentioned several +other genera, apparently more or less closely allied to the present +group, some of which are regarded by Dr. Schlosser as showing marked +signs of affinity to the _Procyonidæ_. Among these are _Simocyon_ from +the Pliocene of Europe, with _p_ ²⁄₂₋₄, _m_ ²⁄₂; and _Enhydrocyon_ of +the North American Miocene, with _p_ ³⁄₃, _m_ ²⁄₂, a secant talon to +the lower carnassial, and a very short skull. The Miocene _Ælurodon_ +comprises several large North American forms, having a trilobed upper +carnassial like that of _Hyænarctus_, and a dental formula similar to +that of the latter and _Canis Prohyæna_ is founded upon a much-worn jaw +of _Ælurodon_. _Hyænocyon_, of the Miocene of the United States, with _p_ +³⁄₃, _m_ ¹⁄₂, appears to be an allied form, also having a trilobed upper +carnassial. + + +_Family_ PROCYONIDÆ. + +True molars ²⁄₂, tuberculated or multicuspid; upper carnassial short and +broad. Alisphenoid canal absent, except in _Ælurus_. Feet plantigrade. +Tail generally annulated. In some cases an entepicondylar foramen to +the humerus. Typically American, but with the outlying Oriental genus +_Ælurus_. + +_Ælurus._[484]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₄, _m_ ²⁄₂; total +38. First lower premolar very minute and deciduous. Molars (Fig. 259) +remarkable for their great transverse breadth and the numerous cusps of +their crowns. Vertebræ: C 7, D 14, L 6, S 3, C 18. Skull (Fig. 259) high +and compressed, very convex, with the facial portion short, the palate +convex antero-posteriorly, and the ascending ramus of mandible extremely +high. Head round. Face short and broad. Ears large, erect, pointed. +Limbs stout, with large sharp semiretractile claws. Tail nearly as long +as body, cylindrical, annulated, and clothed with long hairs. Fur long +and thick. One existing species, _Æ. fulgens_, the Panda (Fig. 258), +an animal rather larger than a Cat, found in the South-East Himalaya, +at heights of from 7,000 to 12,000 feet above the sea, among rocks and +trees, and chiefly feeding on fruits and other vegetable substances. Its +fur is of a remarkably rich reddish-brown colour, darker below. + +The genus _Ælurus_ has been made the type of a distinct family, but its +relationship to the Raccoons is regarded by Mr. W. T. Blanford[485] as +sufficiently close to admit of its being included in the same family. +According to this zoölogist the Panda often sleeps coiled up like a Cat, +with the bushy tail over its head, but at other times resting on its legs +with the head tucked under the chest and between the fore legs, after a +manner said to be common with the Raccoons. Although by no means strictly +nocturnal, these animals sleep much during the day, and roam out in +search of food in the morning and evening. The young are born in a very +helpless condition, and remain for a long period concealed in the holes +of trees or rocks. + +[Illustration: FIG. 258.—The Panda (_Ælurus fulgens_). The dark nasal +stripe shown in this figure is generally absent. (From Sclater, _Proc. +Zool. Soc._ 1869, p. 408.)] + +Fossil remains of a species of _Ælurus_ (_Æ. anglicus_) have been +obtained from the English Pliocene Crag deposits which indicate an animal +of about one and half times the size of _Æ. fulgens_. The first evidence +of this fossil species was afforded by part of the mandible with the +last molar in place, and the subsequent discovery of an entire first +upper molar renders full confirmation of the generic determination. This +distribution of _Ælurus_ is very important, as showing how its area +may have once approximated to that of the ancestors of the American +representatives of the family. It is probable that the genus existed in +India during the Siwalik period. + +The whole of the under-mentioned genera are American, and are +characterised by the absence of an alisphenoid canal in the skull. + +[Illustration: FIG. 259.—Lateral view of skull and right half of palate +of _Ælurus fulgens_. (From Blanford, _Mammalia of British India_, p. +190.)] + +_Procyon._[486]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₂; total 40. +The molar teeth broad and tuberculated (Fig. 259). The upper carnassial +with three cusps along the outer margin, and a very broad bicuspid +inner tubercle, giving an almost quadrate form to the crown. First +molar with a large tuberculated crown, rather broader than long; second +considerably smaller, with transversely oblong crown. Lower carnassial +with an extremely small and ill-defined blade, placed transversely in +front, and a large inner cusp and hind talon. Second molar as long as the +first, but narrower behind, with five obtuse cusps. Vertebræ: C 7, D +14, L 6, S 3, C 16-20. Body stout. Head broad behind, but with a pointed +muzzle. Limbs plantigrade, but in walking the entire sole is not applied +to the ground as it is when the animal is standing. Toes, especially of +the fore foot, very free, and capable of being spread wide apart. Claws +compressed, curved, pointed, and non-retractile. Tail moderately long, +cylindrical, thickly covered with hair, annulated, non-prehensile. Fur +long, thick, and soft. The well-known Raccoon[487] (_Procyon lotor_, +Fig. 260) of North America is the type of this genus. It is a clumsy +thickly-built animal about the size of a Badger, with a coat of long +coarse grayish-brown hairs, short ears, and a bushy black and white +ringed tail. Its range extends over the whole of the United States, and +stretches on the west northwards to Alaska and southwards into Central +America, where it attains its maximum size. The following notes on the +habits of the Raccoon are taken from Dr. C. H. Merriam’s _Mammals of the +Adirondack Region_:— + +[Illustration: FIG. 260.—The Raccoon (_Procyon lotor_).] + +“Raccoons are omnivorous beasts, and feed upon mice, small birds, birds’ +eggs, turtles and their eggs, frogs, fish, crayfish, molluscs, insects, +nuts, fruits, maize, and sometimes poultry. Excepting the bats and flying +squirrels, they are the most strictly nocturnal of all our mammals, and +yet I have several times seen them abroad on cloudy days. They haunt the +banks of ponds and streams, and find much of their food in these places, +such as crayfish, mussels, and fish, although they are unable to dive and +pursue the latter under water, like the otter and mink. They are good +swimmers, and do not hesitate to cross rivers that lie in their path.... +The Raccoon hibernates during the severest part of the winter, retiring +to its nest rather early, and appearing again in February or March, +according to the earliness or lateness of the season. It makes its home +high up in the hollow of some large tree, preferring a dead limb to the +trunk itself. It does little in the way of constructing a nest, and from +four to six young are commonly born at a time, generally early in April +in this region. The young remain with the mother about a year.” + +The South-American _P. cancrivorus_, the Crab-eating Raccoon, is very +similar to _P. lotor_, but differs by its much shorter fur, larger size, +proportionally more powerful teeth, and other minor characters. It +extends over the whole of South America, as far south as the Rio Negro, +and is very common in all suitable localities. Its habits are similar to +those of the North-American species. Fossil remains of _Procyon_ have +been described from the Pleistocene deposits of the United States. + +_Bassaris._[488]—A form closely allied to _Procyon_, but of more slender +and elegant proportions, with a sharper nose, longer tail, and more +digitigrade feet, and with teeth otherwise like, but smaller, and more +sharply denticulated. It was formerly, but erroneously, placed among the +_Viverridæ_. Two species:—_B. astuta_, from the southern parts of the +United States and Mexico, and _B. sumichrasti_, from Central America. + +_Bassaricyon._[489]—This name has been given to a distinct modification +of the Procyonine type of which at present only two examples are known, +one from Costa Rica and the other from Ecuador, which, appearing to be +different species, have been named _B. gabbi_ and _B. alleni_. They much +resemble the Kinkajou (_Cercoleptes_) in external appearance, but the +skull and teeth are more like those of _Procyon_ and _Nasua_. + +_Nasua._[490]—Dentition as in _Procyon_, but the upper canines are +larger and more strongly compressed, and the molars smaller. The facial +portion of the skull is more elongated and narrow. Vertebræ: C 7, D 14, +L 6, S 3, C 22-23. Body elongated and rather compressed. Nose prolonged +into a somewhat upturned, obliquely truncated, mobile snout. Tail long, +non-prehensile, tapering, annulated. These animals, commonly called +Coatis or Coati-Mundis, live in small troops of eight to twenty, are +chiefly arboreal, and feed on fruits, young birds, eggs, insects, etc. +Recent researches have reduced the number of supposed species to two, _N. +narica_ of Mexico and Central America, and _N. rufa_ of South America +from Surinam to Paraguay. Remains of this genus, mostly referable to the +existing species, occur in the cavern-deposits of Brazil. + +_Cercoleptes._[491]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ²⁄₂; total +36. Molars with low flat crowns, very obscurely tuberculated. Skull short +and rounded, with flat upper surface. Vertebræ: C 7, D 14, L 6, S 3, +C 26-29. Clavicles present, but in a very rudimentary condition. Head +broad and round. Ears short. Body long and musteline. Limbs short. Tail +long, tapering, and prehensile. Fur short and soft. Tongue long and very +extensile. But one species of this somewhat aberrant genus is known, _C. +caudivolvulus_, the Kinkajou, found in the forests of the warmer parts of +South and Central America. It is about the size of a Cat, of a uniform, +pale, yellowish-brown colour, nocturnal and arboreal in its habits, +feeding on fruit, honey, eggs, and small birds and mammals, and is of a +tolerably gentle disposition and easily tamed. + + +_Family_ MUSTELIDÆ. + +True molars ¹⁄₂ (or ¹⁄₁ in _Mellivora_[492]). No alisphenoid canal. In +the upper molar the inner tubercular portion is always longer in the +antero-posterior direction than the secant external portion; the degree +of inflation of the auditory bulla is but slight; and the palate is +generally much produced behind the last molars, as is the case with the +members of the preceding family. The post-glenoid process of the cranium +is generally considerably curved over the glenoid fossa, so as to hold +very tightly the condyle of the mandible. The humerus may or may not have +an entepicondylar foramen. Except in the Otters, the kidneys resemble +those of the _Procyonidæ_ in being of simple structure. + +This family is a large and widely distributed one, especially in the +northern temperate regions of the earth. The different genera, which are +very difficult to arrange in any natural order, are rather artificially +divided, chiefly according to the characters of their feet and claws, +into the Otter-like (Lutrine), Badger-like (Meline), and Weasel-like +(Musteline) forms. + +Subfamily =Lutrinæ=.—Feet short, rounded (except the hind feet of +_Latax_). Toes webbed. Claws small, curved, blunt. Head broad and +much depressed. Upper molar large and quadrate, with its inner +tubercular portion much expanded antero-posteriorly (Fig. 261). Kidneys +conglomerate. Habits aquatic. + +_Lutra._[493]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₃, _m_ ¹⁄₂; total 36. +Upper carnassial with a trenchant tricuspid blade, and a very large +inner lobe, hollowed on the free surface, with a raised sharp edge, and +extending along two-thirds or more of the length of the blade. True molar +large, with a quadricuspidate crown, broader than long. First upper +premolar very small, and in some cases absent (Fig. 261). Skull broad and +depressed, contracted immediately behind the orbits. Facial portion very +short; brain case large. Vertebræ: C 7, D 14-15, L 6-5, S 3, C 20-26. +Body very long. Ears short and rounded. Limbs short. Feet more or less +completely webbed; claws usually well developed on all the toes, although +they may be rudimentary or absent. Tail long, thick at the base and +tapering, rather depressed. Fur short and close. The humerus may or may +not have an entepicondylar foramen. In conformity with the shape of the +skull, the posterior part of the brain is expanded laterally. + +[Illustration: FIG. 261.—Palate of _Lutra cinerea_. (From the +_Palæontologia Indica_.)] + +The Common British Otter (_L. vulgaris_), as the type of the genus, may +be described somewhat fully. It has an elongated, low body, short limbs, +short broad feet, with five toes on each, connected together by webs, and +all with short, moderately strong, compressed, curved, pointed claws. +Head rather small, broad, and flat; muzzle very broad; whiskers thick +and strong; eyes small and black; ears short and rounded. Tail a little +more than half the length of the body and head together, very broad and +strong at the base, and gradually tapering to the end, somewhat flattened +horizontally. The fur is of very fine quality, consisting of a short soft +under fur of a whitish-gray colour, brown at the tips, interspersed with +longer, stiffer, and thicker hairs, very shining, grayish at the base, +bright rich brown at the points, especially on the upper parts and outer +surface of the legs; the throat, cheeks, under parts and inner surface of +the legs brownish-gray throughout. Individual Otters vary much in size; +but the total length from the nose to the end of the tail averages about +3½ feet, of which the tail occupies 1 foot 3 or 4 inches. The weight of a +full-sized male is from 18 to 24 lbs., that of a female about 4 lbs. less. + +As the Otter lives almost exclusively on fish, it is rarely met with far +from water, and usually frequents the shores of brooks, rivers, lakes, +and, in some localities, the sea itself. It is a most expert swimmer and +diver, easily overtaking and seizing fish in the water, but when it has +captured its prey it brings it to shore to devour it. When lying upon the +bank it holds the fish between its forepaws, commences at the head, and +then eats gradually towards the tail, which it is said always to leave. +The female produces three to five young ones at a time, in the month of +March or April, and brings them up in a nest formed of grass or other +herbage, usually placed in a hollow place in the bank of a river, or +under the shelter of the roots of some overhanging tree. The Common Otter +is found in localities suitable to its habits throughout Great Britain +and Ireland, though far less abundantly than formerly, for, being very +destructive to fish, and thus coming into keen competition with those +who pursue the occupation of fishing either for sport or for gain, it +is rarely allowed to live in peace when once its haunts are discovered. +Otter-hunting with packs of hounds of a special breed, and trained for +the purpose, was formerly a common pastime in the country. When hunted +down and brought to bay by the dogs, the Otter is finally despatched by +long spears carried for the purpose by the huntsmen. + +The Common Otter ranges throughout the greater part of Europe and Asia, +the Indian _L. nair_ not being distinct. A closely allied but larger +species, _L. canadensis_, is extensively distributed throughout North +America, where it is systematically pursued by professional trappers +for the value of its fur. The Common Otter is regularly trained by the +natives of some parts of Bengal to assist them in fishing, by driving the +fish into the nets. In China Otters are taught to catch fish, being let +into the water for the purpose attached to a long cord. + +Otters are widely distributed over the earth, and, as they are much +alike in size and coloration, their specific distinctions are by no +means well defined.[494] Besides those mentioned above, the following +may be noticed. In the Oriental region there are _L. ellioti_[495] of +India, _L. sumatrana_ of the Malay countries, and _L. cinerea_ ranging +over the greater part of the region. The latter species (often known +as _L. leptonyx_) is of small size, with a short head, and rudimentary +claws, which may be absent; it was at one time regarded as generically +distinct, under the name of _Aonyx_. The upper true molar (Fig. 261) is +characterised by the great development of its inner tubercular portion, +and the first upper premolar is absent. In the Ethiopian region there +are two species, _L. capensis_ and _L. maculicollis_. Of the Neotropical +forms it will suffice to mention the small _L. felina_ and the large _L. +brasiliensis_. The latter is by far the largest of the existing forms, +and is characterised by the presence of a prominent flange-like ridge +along each lateral margin of the tail, on which account it was referred +by Dr. Gray to a distinct genus, with the name of _Pteronura sambachi_. +It should be observed that all Otters have a very distinct inner cusp to +the blade of the lower carnassial, but that the relative size of this +cusp varies in the different species. + +_Extinct Otters._—Several species of fossil Otters have been +described. Thus in the Indian Siwaliks we have _L. palæindica_, which +is closely allied to _L. sumatrana_, and a larger form described +as _L. bathygnathus_. The Pliocene of Hessen-Darmstadt yields _L. +hessica_; while _L. dubia_, of the Middle Miocene of France, is a +species characterised by the small size of the inner cusp of the lower +carnassial—a character in which it resembles those Tertiary forms +described as _Trochictis_, which are believed to connect _Lutra_ with the +_Mustelinæ_. Two very large Otters, respectively from the Indian Siwaliks +and the Italian Miocene, named _L. sivalensis_ and _L. campanii_, may +be regarded either as representing a very distinct _Enhydriodont_ group +of _Lutra_ or as referable to a separate genus _Enhydriodon_. They are +characterised by certain peculiarities in the structure of the teeth, +and the second upper premolar may be absent in the Indian form. Lastly, +the genus _Potamotherium_ contains a small Otter (_P. valetoni_) from +the Lower Miocene of the Continent, which differs from all other known +_Mustelidæ_ in having a minute second upper true molar. This species is +evidently a very generalised form approximating to the _Viverridæ_ in +its dental formula, and also in the characters of the teeth themselves. +The brain, as recently described by Dr. Filhol, differs from that +of _Lutra_ and other Mustelines in the great relative width of the +anterior extremity of the hemispheres and olfactory lobes, and also in +the disposition of the sulci, in both of which respects it more nearly +resembles the _Viverridæ_. + +_Latax._[496]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ¹⁄₂; total 32. +Differs from all other existing Carnivora in having but two incisors on +each side of the lower jaw, the one corresponding to the first (very +small in the true Otters) being constantly absent. Though the molar teeth +generally resemble those of _Lutra_ in their proportions, they differ +very much in the exceeding roundness and massiveness of their crowns +and bluntness of their cusps. Feet webbed. Fore feet small, with five +subequal toes, furnished with short compressed claws; palms naked. Hind +feet very large, depressed, and fin-like. The phalanges flattened as in +the Seals. The fifth toe the longest and stoutest, the rest gradually +diminishing in size to the first, all with moderate claws. Tail +moderate, cylindrical, and obtuse; about one-fourth the length of the +head and body. + +The Sea-Otter (_L. lutris_, Fig. 262) is the sole representative of +this genus. The entire length of the animal from nose to end of tail +is about 4 feet, so that the body is considerably larger and more +massive than that of the English Otter. The skin is peculiarly loose, +and stretches when removed from the animal so as to give the idea of +a still larger creature than it really is. The pellage is remarkable +for the preponderance of the beautifully soft woolly under fur, the +longer stiffer hairs being very scanty. The general colour is a deep +liver brown, everywhere silvered or frosted with the hoary tips of the +longer hairs. These are, however, removed when the skin is dressed for +commercial purposes. + +[Illustration: FIG. 262.—The Sea-Otter (_Latax lutris_). From Wolf, +_Proc. Zool. Soc._ 1865, pl, vii.] + +Sea-Otters are only found upon the rocky shores of certain parts of +the North Pacific Ocean, especially the Aleutian Islands and Alaska, +extending as far south on the American coast as Oregon; but, owing to the +unremitting persecution to which they are subjected for the sake of their +skins, which rank among the most valuable known to the furrier, their +numbers are greatly diminishing, and, unless some restriction can be +placed upon their destruction, such as that which protects the Fur-Seals +of the Pribyloff Islands, the species is threatened with extermination, +or, at all events, excessive scarcity. When this occurs, the occupation +of five thousand of the half-civilised natives of Alaska, who are +dependent upon Sea-Otter hunting as a means for obtaining their living, +will be gone. The principal hunting grounds at present are the little +rocky islets and reefs around the island of Saanach and the Chernobours, +where they are captured by spearing, clubbing, or nets, and recently +by the more destructive rifle bullet. They do not feed on fish, like +the true Otters, but on clams, mussels, sea-urchins, and crabs, for the +mastication of which the blunt cusps of their teeth are admirably suited. +The female brings forth but a single young one at a time, apparently +at any season of the year. They are excessively shy and wary, and all +attempts to rear the young ones in captivity have hitherto failed. + +Subfamily =Melinæ=.—Feet elongated. Toes straight. Claws non-retractile, +slightly curved, subcompressed, blunt; those of the fore foot especially +large. Upper molar variable. Kidneys simple. Habits mostly terrestrial +and fossorial. + +_Mephitis._[497]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ¹⁄₂; total +34. Upper molar larger than the carnassial, subquadrate, rather broader +than long. Lower carnassial with talon less than half the length of +the whole tooth. Bony palate terminating posteriorly opposite the +hinder border of the last molar tooth. Facial portion of skull short +and somewhat truncated in front. Vertebræ: C 7, D 16, L 6, S 2, C 21. +Head small. Body elongated. Limbs moderate, subplantigrade. Ears short +and rounded. Tail long, abundantly clothed with very long fine hair. +Anal glands largely developed. The secretion of these glands, which can +be discharged at the will of the animal, has an intolerably offensive +odour, which circumstance has rendered the Skunks, as they are commonly +called, proverbial. They are strictly nocturnal animals, terrestrial and +burrowing, feeding chiefly on small mammals, birds, reptiles, insects, +worms, roots, and berries. All the known species have a prevalent black +colour, varied by white strips or spots on the upper part (Fig. 263). +They generally carry the body, much arched, and the tail erect, the long +loose hair of which waves like a plume over the back. There are three +species, all inhabitants of the American continent, over which they have +an extensive range. + +[Illustration: FIG. 263.—The Common Skunk (_Mephitis mephitica_).] + +The Common Skunk (_M. mephitica_, Fig. 263) is an animal of about +the size of a small Cat, ranging from Hudson’s Bay to Guatemala. The +following account of its habits is given by Dr. C. H. Merriam in his +_Mammals of the Adirondack Region_:— + +“The skunk preys upon mice, salamanders, frogs, and the eggs of birds +that nest on or within reach from the ground. At times he eats carrion, +and if he chances to stumble upon a hen’s nest the eggs are liable to +suffer; and once in a while he acquires the evil habit of robbing the +hen-roost, but as a rule skunks are not addicted to this vice. Of all +our native mammals perhaps no one is so universally abused and has so +many unpleasant things said about it as the innocent subject of the +present biography; and yet no other species is so valuable to the farmer. +Pre-eminently an insect-eater, he destroys more beetles, grasshoppers, +and the like than all our other mammals together, and in addition to +these he devours vast numbers of mice. He does not evince that dread of +man that is so manifest in the great majority of our mammals, and when +met during any of his circumambulations rarely thinks of running away. He +is slow in movement and deliberate in action, and does not often hurry +himself in whatever he does. His ordinary gait is a measured walk, but +when pressed for time he breaks into a low shuffling gallop. It is hard +to intimidate a skunk, but when once really frightened he manages to get +over the ground at a very fair pace. Skunks remain active throughout the +greater part of the year in this region, and hibernate only during the +severest portion of the winter. They differ from most of our hibernating +mammals in that the inactive period is apparently dependent solely on the +temperature, while the mere amount of snow has no influence whatever upon +their movements. Skunks, particularly when young, make very pretty pets, +being attractive in appearance, gentle in disposition, interesting in +manners, and cleanly in habits—rare qualities indeed! They are playful, +sometimes mischievous, and manifest considerable affection for those who +have the care of them. Their flesh is white, tender, and sweet, and is +delicious eating. Skunks have large families, from six to ten young being +commonly raised each season; and as a rule they all live in the same hole +until the following spring.” + +The two ducts leading from the anal glands open at the tips of two small +conical papillæ placed in such a position that the animal can protrude +them externally, and can thus guide the direction of the jet of nauseous +fluid, which can be propelled by the powerful muscles surrounding the +glands to a distance of from 8 to 12 feet. + +The Long-tailed Skunk (_M. macrura_), from Central and Southern Mexico, +has two lateral stripes, and a longer and more bushy tail than the +common species. _M. putorius_, of the Southern United States and thence +southwards to Yucatan and Guatemala, is of a much smaller size, with four +interrupted white lateral stripes, and a skull differing considerably in +form from that of the type species. It is regarded by some writers as +representing a distinct genus, _Spilogale_; and has been recently divided +by Dr. C. H. Merriam into several nominal species. + +_Conepatus._[498]—The Skunk of tropical America (_C. mapacito_), ranging +from Texas to Chili and Patagonia, differs considerably from the true +Skunks, although in colour it is almost precisely similar to the common +species, with which it also agrees in the variation of the relative +development of the black and white. Its build is heavier than that of +_Mephitis_; the snout and head are more Pig-like; and the nostrils open +downwards and forwards instead of laterally on the sides of the muzzle. +The skull also has many special characters, and the teeth are different +in shape and, as, a rule, in number also, the first minute premolar of +_Mephitis_ being almost invariably absent, so that the dental formula is +_i_ ³⁄₃, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ¹⁄₂; total 32. + +Remains of _Conepatus_, which have been referred to three species, are +found in the cavern-deposits of Brazil. + +_Arctonyx._[499]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ¹⁄₂; total +38. Incisor line curved, the outer teeth being placed posteriorly to the +others. Lower incisors proclivous. First premolars often rudimentary +or absent. Upper molar much larger than the carnassial, longer in the +antero-posterior direction than broad; lower carnassial with a very +large, low, tuberculated talon. Cranium elongated and depressed; face +long, narrow, and concave above. Bony palate extending as far backwards +as the level of the glenoid fossa; palatal bones dilated; suborbital +foramina very large. Vertebræ: C 7, D 16, L 4, S 4, C 20. Snout long, +naked, mobile, and truncated, with large terminal nostrils, much like +that of a Pig. Eyes small. Ears very small and rounded. Body compressed +rather than depressed. Limbs of moderate length and digitigrade in +walking. Tail moderate, tapering. A full soft under fur, with longer, +bristly hairs interspersed. The best-known species is _A. collaris_, +the Sand-Badger, or _Bhálu-soor_[500] (_i.e._ Bear-pig) of the natives, +found in the mountains of the north-east of India and Assam. It is rather +larger than the English Badger, higher on its legs, and very Pig-like +in general aspect, of a light gray colour, with flesh-coloured snout +and feet; and is nocturnal and omnivorous in habits. The imperfectly +known _A. taxoides_ from Assam and Arakan, and perhaps China, is a much +smaller species. A third form probably exists in Eastern Tibet. Professor +Mivart remarks that the brain-case of _Arctonyx_ is narrower than in any +other Arctoid; while the palate is relatively longer than in any other +Carnivore except _Procyon_; and the metatarsus is relatively shorter than +in any other member of the order. + +_Mydaus._[501]—Dentition as in the last genus, but the cusps of the +teeth more acutely pointed. Cranium elongated, face narrow and produced. +Suborbital foramen small, and the palate, as in all the succeeding genera +of this group, produced backwards about midway between the last molar +tooth and the glenoid fossa. Vertebræ: C 7, D 14-15, L 6-5, S 3, C 12. +Head pointed in front; snout produced, mobile, obliquely truncated, the +nostrils being inferior. Limbs rather short and stout. Tail extremely +short, but clothed with rather long bushy hair. Anal glands largely +developed, and emitting an odour like that of the American Skunks. One +species, _M. meliceps_, the Teledu, a small burrowing Badger, found +in the mountains of Java at an elevation of 7000 or more feet above +sea-level. + +_Meles._[502]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ¹⁄₂; total 38. +The first premolar in both jaws extremely minute and often deciduous. +Upper molar very much larger than the carnassial, subquadrate, as broad +as long. Lower carnassial with a broad, low, tuberculated talon, more +than half the length of the whole tooth. The post-glenoid processes of +the skull are so strongly developed, and the glenoid fossa is so deep, +that the condyle of the lower jaw is firmly held in its place even after +all the surrounding soft parts are removed. Vertebræ: C 7, D 15, L 5, S +3, C 18. Muzzle pointed. Ears very short. Body stout, broad. Limbs short, +strong, subplantigrade. Tail short. The best-known species is the common +Badger (_M. taxus_) of Europe and Northern Asia, still found in many +parts of England, where it lives in woods, is nocturnal, burrowing, and +very omnivorous, feeding on mice, reptiles, insects, fruit, acorns, and +roots. Other nearly allied species, _M. leucurus_ and _M. chinensis_, are +found in continental Asia, _M. canescens_ in Persia, and _M. anakuma_ in +Japan. + +The appearance of the common Badger is too well known to need +description, but, it may be mentioned that a full-grown individual stands +about a foot in height at the shoulder, and measures from 2½ to 3 feet +in length. The young are born in a naked and blind condition, usually in +litters of three or four. It appears that the usual period of gestation +is about eleven and a half months, but instances are recorded where the +period has been protracted to upwards of fifteen months. + +Fossil remains of the common Badger are found in the Pleistocene deposits +of Europe, while extinct species have been described from the Lower +Pliocene beds of Maragha, in Persia. + +_Taxidea._[503]—Dental formula as in _Meles_, except that the rudimentary +anterior premolar appears to be always wanting in the upper jaw. The +upper carnassial much larger in proportion to the other teeth. Upper +molar about the same size as the carnassial, triangular, with the apex +turned backwards. Talon of lower carnassial less than half the length +of the tooth. Skull very wide in the occipital region; the lambdoidal +crest very greatly developed, and the sagittal but slightly, contrary to +what obtains in _Meles_. Vertebræ: C 7, D 15, L 5, S 3, C 16. Body very +stoutly built and depressed. Tail short. The animals of this genus are +peculiar to North America, where they represent the Badgers of the Old +World, resembling them much in appearance and habits. _T. americana_ is +the common American Badger of the United States; _T. berlandieri_, the +Mexican Badger, is perhaps only a local variety. + +_Mellivora._[504]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ¹⁄₁; total +32. Upper carnassial large, with its inner tubercle quite at the anterior +end of the blade, as in the following genera; molar much smaller and +transversely extended, having a very small outer and a larger rounded +inner lobe. Talon of lower carnassial very small, scarcely one-fourth of +the whole length of the tooth, and with but one cusp; lower tubercular +molar absent. Vertebræ: C 7, D 14, L 4, S 4, C 15. Body stout, depressed. +Limbs short, strong. Head depressed, nose rather pointed. External ears +rudimentary. Tail short. The animals of this genus are commonly called +Ratels. _M. indica_ from India, and, _M. ratel_ (Fig. 264) from South +and West Africa, have nearly the same general appearance and size, being +rather larger than a common Badger. Their coloration is peculiar, all +the upper surface of the body, head, and tail being ashy gray, while the +lower parts, separated by a distinct longitudinal boundary line, are +black. The two species may be distinguished by the circumstance that the +African one has a distinct white line round the body at the junction of +the gray of the upper side with the black of the lower, while in the +Indian form this line is absent; the teeth also of the former are, on the +whole, larger, rounder, and heavier than those of the latter. In spite of +these differences the two are, however, so nearly allied that they might +almost be considered as local races of a single widely spread species. + +[Illustration: FIG. 264.—The African Ratel (_Mellivora ratel_).] + +The following account of the Indian species is extracted from Dr. +Jerdon’s _Mammals of India_: “The Indian badger is found throughout the +whole of India, from the extreme south to the foot of the Himalayas, +chiefly in hilly districts, where it has greater facilities for +constructing the holes and dens in which it lives; but also in the north +of India in alluvial plains, where the banks of large rivers afford +equally suitable localities wherein to make its lair. It is stated to +live usually in pairs, and to eat rats, birds, frogs, white ants, and +various insects, and in the north of India it is accused of digging out +dead bodies, and is popularly known as the grave-digger. It doubtless +also, like its Cape congener, occasionally partakes of honey. It is often +very destructive to poultry, and I have known of several having been +trapped and killed whilst committing such depredations in Central India +and in the northern Circars. In confinement the Indian badger is quiet +and will partake of vegetable food, fruits, rice, etc.” + +A fossil species of _Millivora_, apparently closely allied to the +existing forms, occurs in the Pliocene Siwaliks of India. The same +deposits have also yielded remains of an extinct genus described as +_Mellivorodon_. + +[Illustration: FIG. 265.—_Helictis personata._ (From Blanford, _Mammalia +of British India_, p. 175.)] + +_Helictis._[505]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ¹⁄₂; total +38. Upper carnassial with a large bicuspid inner tubercle; upper molar +smaller, wider transversely than in the antero-posterior direction. +Lower carnassial with talon about one-third the length of the tooth. +Skull elongated, rather narrow and depressed. Facial portion especially +narrow. Infraorbital foramen very large. Head rather small and produced +in front, with an elongated, obliquely truncated, naked snout. Ears +small. Body elongated. Limbs short. Tail short or moderate, bushy. +Several species are described (_H. orientalis_, _personata_ [Fig. 265], +_moschata_, _subaurantiaca_), all from Eastern Asia; they are all small +animals compared with the other members of the subfamily, climbing trees +with agility and living much on fruit and berries as well as on small +mammals and birds. The two first named species occur in British India, +_H. orientalis_ also ranging into Java; the Chinese _H. subaurantiaca_ is +brilliantly coloured in the region of the throat.[506] + +[Illustration: FIG. 266.—Left lateral and superior aspect of the brain of +_Helictis subaurantiaca_. (From Garrod, _Proc. Zool. Soc._ 1879, p. 307.)] + +The brain of _Helictis_, represented in the accompanying figure, shows +the general type of cerebral structure characteristic of the _Mustelidæ_. +The brain of this genus differs, however, from that of every other +Carnivore in that the hippocampal gyrus rises to the surface on either +side of the great longitudinal fissure, in consequence of which there is +no crucial fissure, and the so-called “Ursine lozenge,” so characteristic +of the Arctoidea, is incomplete behind. The superior gyrus, as in +_Ictonyx_ and _Mustela_, ceases at the superior posterior angle of the +hemisphere. + +_Ictonyx._[507]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ¹⁄₂; total +34. In general characters the teeth much resemble those of the Polecats +(_Mustela_), being more delicately cut and sharply cusped than in most +of the foregoing. Upper molar smaller than the carnassial, narrow from +before backwards. Lower carnassial with a small narrow talon and distinct +inner cusp. General form of body Musteline. Limbs short. Fore feet large +and broad, with five stout, nearly straight, blunt, and non-retractile +claws, of which the first and fifth are considerably shorter than the +others. Tail moderate, with longer hairs towards the end, giving it a +bushy appearance. Hairs generally long and loose. The best known species +of this genus, _I. zorilla_, the Cape Polecat, was placed by Cuvier in +the genus _Mustela_, and by Lichtenstein in _Mephitis_; and in many +characters it forms a transition between these genera. It is about the +size of an English Polecat, but conspicuous by its coloration, having +broad, longitudinal bands of dark brown, alternating with white. Its +odour is said to be as offensive as that of the American Skunks. From the +Cape of Good Hope it ranges as far north as Senegal. Another species, _I. +frenata_, from Sennaar and Egypt, has been described. + +Subfamily =Mustelinæ=.—Toes short, partially webbed; claws short, +compressed, acute, curved, often semiretractile. Upper molar of moderate +size, wide transversely. Kidneys simple. Terrestrial and arboreal in +habits. + +_Galictis._[508]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ¹⁄₂; total 34. +Molars small but stout. Upper carnassial with the inner tubercle near +the middle of the inner border of the tooth. Lower carnassial with talon +small, and inner cusp small or absent. Body long. Limbs short; claws +non-retractile. Palms and soles naked. Head broad and depressed. Tail +of moderate length. The best-known species are _G. vittata_, the Grison +(genus _Grisonia_, Gray), and _G. barbara_, the Tayra (genus _Galera_, +Gray), both South American; _G. allamandi_ is an intermediate form. + +Remains of _Galictis_ occur in the Pleistocene cavern-deposits of Brazil, +and also in the Pleistocene of North America. + +_Mustela._[509]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁻⁴⁄₃₋₄, _m_ ¹⁄₂; total +34 or 38. Upper carnassial with inner tubercle close to the anterior edge +of the tooth. Molar nearly as large as carnassial. Lower carnassial with +small or no inner cusp. Vertebræ: C 7, D 14, L 6, S 3, C 18-23. Body long +and slender. Limbs short, digitigrade. Feet rounded; toes short, with +compressed, acute, semiretractile claws. Tail moderate or long, more or +less bushy. + +The genus _Mustela_, as restricted by Cuvier (_Règne Animal_, 1817), +contains a very natural assemblage of animals commonly called Martens, +Sables, Polecats, Stoats, Ermines, and Weasels, all closely allied in +structure and habits. A structural division, however, occurs between the +two first-named and all the others, especially shown in the presence +of an additional small premolar tooth on each side of the jaw; and, +availing himself of this and some other minor characters, Cuvier divided +the genus into two subgenera, for the first of which he retained the +name of _Mustela_, and to the second assigned that of _Putorius_. Three +years later Nilsson (_Skand. Fauna_, 1820) definitely constituted the +two groups into genera, applying to the first the name of _Martes_, by +which the animals composing it had been generally designated by the Latin +writing zoologists of the preceding century, and keeping _Mustela_ for +the more typical Weasels and their immediate allies. Later zoologists +have been divided between the nomenclature of Cuvier, which has the +priority, and that of Nilsson, which on other grounds is preferable. +Those who adopt the latter affirm that Cuvier’s names, being only used +by him in a subgeneric sense, and not binominally, need not be applied +generically, but this is contrary to the practice usually followed in +such cases; and therefore, if the original genus be divided, the name +_Mustela_ should be retained for the Martens, and _Putorius_ for the +Polecats and Weasels. Here, however, the genus will be employed in its +wider sense, and divided into two groups. + +The typical group of the Martens[510] presents the following distinctive +features. Body long, slender, and very flexible, though less so than in +the true Weasels. Head somewhat triangular; muzzle pointed, the nose +extending a little beyond the lips; eyes large and prominent; ears +conspicuous, broad, somewhat triangular, rounded at the ends, furred +outside and in. Limbs short; feet rounded; toes short, five on each +foot, all with short, compressed, curved, sharp-pointed claws; soles +densely furred between the naked pads. Tail moderately long, more or +less bushy. Outer fur long, strong, and glossy; a very abundant soft +under fur. Skull elongated and depressed. Facial portion moderate and +rather compressed. Zygomata arched and wide, but slender. Postorbital +processes small. Auditory bullæ large, but not very globose. Mandible +with a strong triangular vertical coronoid process and a well-developed +angular process. Premolars ⁴⁄₄. Upper incisors in a straight transverse +line, rather long and compressed; first and second subequal, third +considerably larger. Lower incisors very small, especially the first, and +crowded together, the second placed rather behind the others. Canines +long and sharp-pointed. Upper premolars: first very small, with simple +crown and one root; second and third nearly equal in size and two-rooted, +with simple compressed sharp-pointed crowns, with very slightly developed +accessory cusps; fourth (the carnassial) with blade consisting chiefly of +the central and posterior lobes, the anterior being rudimentary, inner +tubercle small and confined to the anterior part of the tooth. True molar +tubercular, about twice as wide transversely as in the antero-posterior +direction, having an outer, more elevated, but smaller portion, bearing +three blunt tubercles; to the inner side of this the crown is contracted, +and its surface deeply hollowed; it then expands again into a broad low +lobe, with the central part elevated, and a raised, even, semicircular, +slightly crenated internal border. Lower premolars: first very small, +simple, and one-rooted; second, third, and fourth increasing slightly in +size, with high compressed pointed crowns and posterior accessory cusps, +best marked in the third. First molar (carnassial) with well-marked +bilobed blade, talon scarcely more than one-third of the length of the +tooth, and a very small inner cusp. Second molar small, single-rooted, +with a low, flattened, subcircular or oval tubercular crown. + +In geographical distribution the Martens are limited to the northern +hemisphere, ranging throughout the greater part of the temperate regions +of both Old and New Worlds, as far north as conditions of existence +suited to their habits are met with, and southwards in America to 35° N. +lat., while in Asia one species is met with as far in this direction as +the island of Java. + +The various species appear to be very similar in their habits. They +live in woods and rocky places, and are thoroughly arboreal, spending +most of their time in trees, although descending to the ground in quest +of prey. They climb with great facility, and are agile and graceful in +their movements. Some species are said occasionally to resort to berries +and other fruit for food, but as a rule they are strictly carnivorous, +feeding chiefly on birds and their eggs, small mammals, as squirrels, +hares, rabbits, and moles, but chiefly mice of various kinds, of which +they destroy great numbers, and occasionally snakes, lizards, and frogs. +In proportion to their size they are among the most bloodthirsty of +animals, though less so than the true Weasels. The female usually makes +her nest of moss, dried leaves, and grass in the hollow of a tree, but +sometimes in a hole among rocks or ruined buildings, and produces several +young at a birth, usually from four to six. Though wild and untameable +to a great degree if captured when fully grown, when taken young they +are very docile, and have frequently been made pets of, not having the +strong unpleasant odour of the smaller _Mustelidæ_. The common European +Marten appears to have been partially domesticated by the Greeks and +Romans, and to have been used to keep houses clear from rats and mice +before cats were introduced.[511] In the same way, according to Hodgson, +the Yellow-bellied Weasel (_M. cathia_) “is exceedingly prized by the +Nipalese for its service in ridding houses of rats. It is easily tamed; +and such is the dread of it common to all Murine animals that not one +will approach a house where it is domiciled.” It is, however, to the +great value attached to the pelts of these animals that their importance +to man is chiefly due. Though all yield fur of serviceable quality, the +commercial value varies immensely, not only according to the particular +species from which it is obtained, but according to individual variation, +depending upon age, sex, season, and other trifling circumstances. The +skins from northern regions are more full and of a finer colour and gloss +than those from more temperate climates, as are those of animals killed +in winter compared with the same individuals in the summer season. The +caprices of fashion have, moreover, set wholly factitious values upon +slight shades of colour, recognised and named by experienced furriers, +but not indicating any specific or other distinctions of which zoologists +have any cognisance. Enormous numbers of animals are annually caught, +chiefly in traps, to supply the demand of the fur trade, Siberia and +North America being the principal localities from which they are obtained. + +With the exception of the Pekan (_M. pennanti_) all the Martens are so +much alike in size, general colouring, and cranial and dental characters +that the discrimination of the species, and assignment of the proper +geographical distribution to each, has been a subject which has sorely +perplexed the ingenuity and patience of zoologists. The following +description by Dr. Elliott Coues of the external characters of the +American Pine Marten (_M. americana_) will apply almost equally well +to most of the others: “It is almost impossible to describe the colour +of the Pine Marten, except in general terms, without going into the +details of the endless diversities occasioned by age, sex, season, or +other incidents. The animal is ‘brown,’ of various shades from orange or +tawny to quite blackish; the tail and feet are ordinarily the darkest, +the head lightest, often quite whitish; the ears are usually rimmed +with whitish; on the throat there is usually a large tawny-yellowish or +orange-brown patch, from the chin to the fore legs, sometimes entire, +sometimes broken into a number of smaller, irregular blotches, sometimes +wanting, sometimes prolonged on the whole under surface, when the animal +is bicolor like a Stoat in summer. The general ‘brown’ has a grayish +cast, as far as the under fur is concerned, and is overlaid with rich +lustrous blackish-brown in places where the long bristly hairs prevail. +The claws are whitish; the naked nose pad and whiskers are black. The +tail occasionally shows interspersed white hairs, or a white tip.” + +The species generally recognised as distinct are the following, the first +five belonging to the Old and the last two to the New World:— + +_M. foina_, the Beech Marten, Stone Marten, or White-breasted +Marten.—Distinguished from the following by the greater breadth of the +skull, and some minute but constant dental characters, by the dull +grayish-brown colour of the fur of the upper parts, and the pure white +of the throat and breast. It inhabits the greater part of the continent +of Europe, but is more southern than the next in its distribution, not +being found in Sweden or Norway, nor, according to the investigations of +Mr. Alston, in the British Isles, although included in their fauna by +all earlier writers; to the eastward it ranges into Afghanistan and the +Himalaya. + +[Illustration: FIG. 267.—The Pine Marten (_Mustela martes_).] + +_M. martes_, the Pine Marten (Fig. 267).—Outer fur rich dark brown; under +fur reddish-gray, with clear yellow tips; breast spot usually yellow, +varying from bright orange to pale cream-colour or yellowish-white. +Length of head and body 16 to 18 inches; of tail (including the hair) 9 +to 12 inches. This species is extensively distributed throughout northern +Europe and Asia, and was formerly common in most parts of Great Britain +and Ireland. Though commonly called “Pine Marten,” it does not appear to +have any special preference for coniferous trees, except that, inasmuch +as they constitute the greater proportion of the forests of the countries +which it inhabits, it is more often met with in them than in any other. +With regard to its recent occurrence in the British Isles, Mr. Alston +writes in the _Proc. Zool. Soc._ 1879:— + +“Although greatly reduced in numbers by persecution, it still maintains +its ground in the wilder districts of Scotland, the north of England, +Wales, and Ireland; and occasionally specimens are killed in counties +where the species was thought to have been long extinct. In Scotland it +is still found, though comparatively rarely, in the Lews and in most of +the Highland mainland counties, being perhaps most abundant in Sutherland +and Ross-shire, especially in the deer forests. In the Lowlands a Marten +is now a very great rarity; but a fine example was killed in Ayrshire +in the winter of 1875-76. In the north of England Mr. W. A. Durnford +says the species is still plentiful in the wilder parts of Cumberland, +Westmoreland, and Lancashire, and in Lincolnshire several have been +recorded, the latest killed in 1865, by Mr. Cordeaux. In Norfolk one +was shot last year; and I have myself examined a fine example which was +shot in Hertfordshire, within 20 miles of London, in December 1872. In +Dorsetshire the last is said to have been killed in 1804; but a specimen +occurred in Hampshire about forty years ago, and another in Surrey in +1847. In Ireland the following counties were enumerated by Thompson as +habitats of this species: Donegal, Londonderry, Antrim, Down, Armagh, +Fermanagh, Longford, Galway, Tipperary, Cork, and Kerry. The _Cat-crann_ +is probably now a rarer animal in Ireland than it was when Thompson +wrote; but it still exists in various districts, especially in County +Kerry, whence the society has received several living examples; and +Professor A. Leith Adams states that it has been seen of late years even +in county Dublin.” + +_M. zibellina_, the Sable (German, _Zobel_ and _Zebel_; Swedish, _sabel_; +Russian, _sobel_, a word probably of Turanian origin).—Closely resembling +the last, if indeed differing from it except in the quality of the fur, +which is the most highly valued of that of all the group. Found chiefly +in Eastern Siberia. + +_M. flavigula_, the Indian Marten.—Inhabits the southern slopes of the +Himalaya, the Nilgiri Hills, the interior of Ceylon, the Malay Peninsula, +and Java. The coloration of this species is very striking, the upper +parts being blackish-brown, and the throat and breast yellow or orange, +in the bright coloured variety. It differs from the other species in +having the soles of the feet more or less naked. + +_M. melampus._—Japan. + +_M. americana_, the North-American Sable or Marten.—A species so closely +allied to the European Pine Marten and Asiatic Sable that it is very +difficult to assign constant distinguishing characters between them. The +importance of the fur of this animal as an article of commerce may be +judged of from the fact that 15,000 skins were sold in one year by the +Hudson’s Bay Company as long ago as 1743, and the more recent annual +imports into Great Britain have exceeded 100,000. It is ordinarily caught +in wooden traps of very simple construction, being little enclosures of +stakes or brush in which the bait is placed upon a trigger, with a short +upright stick supporting a log of wood, which falls upon its victim on +the slightest disturbance. A line of such traps, several to a mile, often +extends many miles. The bait is any kind of meat, a mouse, squirrel, +piece of fish, or bird’s head. It is principally trapped during the +colder months, from October to April, when the fur is in good condition, +as it is nearly valueless during the shedding in summer. Dr. Coues tells +us that, notwithstanding the persistent and uninterrupted destruction to +which the American Sable is subjected, it does not appear to diminish +materially in numbers in unsettled parts of the country. It holds its own +partly in consequence of its shyness, which keeps it away from the abodes +of men, and partly because it is so prolific, bringing forth six to eight +young at a litter. Its home is sometimes a den under ground or beneath +rocks, but oftener the hollow of a tree, and it is said frequently to +take forcible possession of a squirrel’s nest, driving off or devouring +the rightful proprietor. + +_M. pennanti_, the Pekan or Pennant’s Marten, also called Fisher +Marten, though there appears to be nothing in its habits to justify the +appellation.—This is the largest species of the group, the head and +body measuring from 24 to 30 inches, and the tail 14 to 18 inches. It +is also more robust in form than the others, its general aspect being +more that of a Fox than a Weasel; in fact, its usual name among the +American hunters is “Black Fox.” Its general colour is blackish, lighter +by mixture of brown or gray on the head and upper fore part of the body, +with no light patch on the throat, and unlike the other Martens generally +darker below than above. It was generally distributed in wooded districts +throughout the greater part of North America, as far north as Great Slave +Lake, 63° N. lat., and Alaska, and extending south to the parallel of +35°; but at the present time it is almost exterminated in the settled +parts of the United States east of the Mississippi. + +Fossil remains of a Marten from the Pliocene Siwaliks of India indicate a +species which cannot be distinguished from those now inhabiting the same +region; while remains of _M. martes_ occur in European cavern-deposits, +and in the fens of Cambridgeshire. + +With the _Putoriine_ group (genus _Putorius_) we come to those smaller +forms distinguished by having only three premolars in each jaw, by the +absence of an inner cusp to the blade of the lower carnassial, as well as +by certain external characters. This group contains a few species known +as Minks, differing from the rest by slight structural modifications, +and especially by their semiaquatic habits. They are distinguished +from the Polecats, Stoats, and Weasels, which constitute the remainder +of the group, by the facial part of the skull being narrower and +more approaching in form that of the Martens, by the premolar teeth +(especially the anterior one in the upper jaw) being larger, by the toes +being partially webbed, and by the absence of hair in the intervals +between the naked pads of the soles of the feet. The two best-known +species, so much alike in size, form, colour, and habits that although +they are widely separated geographically some zoologists question their +specific distinction, are _M. lutreola_, the _Nörz_ or _Sumpfotter_ +(Marsh-Otter) of Eastern Europe, and _M. vison_, the Mink of North +America. The former inhabits Finland, Poland, and the greater part of +Russia, though not found east of the Ural Mountains. Formerly it extended +westward into Central Germany, but is now very rare, if not extinct, +in that country. The latter is found in places which suit its habits +throughout the whole of North America. Another form, _M. sibirica_, from +Eastern Asia, of which much less is known, appears to connect the true +Minks with the Polecats. + +For the following description, chiefly taken from the American form +(though almost equally applicable to that of Europe), we are mainly +indebted to Dr. Coues’s _Fur-bearing Animals of North America_. In size +it much resembles the English Polecat,—the length of the head and body +being usually from 15 to 18 inches, that of the tail to the end of the +hair about 9 inches. The female is considerably smaller than the male. +The tail is bushy, but tapering at the end. The ears are small, low, +rounded, and scarcely project beyond the adjacent fur. The pellage +consists of a dense, soft, matted under fur, mixed with long, stiff, +lustrous hairs on all parts of the body and tail. The gloss is greatest +on the upper parts; on the tail the bristly hairs predominate. Northern +specimens have the finest and most glistening pellage; in those from +southern regions there is less difference between the under and over +fur, and the whole pellage is coarser and harsher. In colour different +specimens present a considerable range of variation, but the animal is +ordinarily of a rich dark brown, scarcely or not paler below than on the +general upper parts; but the back is usually the darkest, and the tail is +nearly black. The under jaw, from the chin about as far back as the angle +of the mouth, is generally white. In the European Mink the upper lip is +also white, but as this occasionally occurs in American specimens it +fails as an absolutely distinguishing character. Besides the white on the +chin, there are often other irregular white patches on the under parts of +the body. In very rare instances the tail is tipped with white. The fur, +like that of most of the animals of the group to which it belongs, is an +important article of commerce. + +The principal characteristic of the Mink in comparison with its congeners +is its amphibious mode of life. It is to the water what the other Weasels +are to the land, or Martens to the trees, being as essentially aquatic +in its habits as the Otter, Beaver, or Musk-Rat, and spending perhaps +more of its time in the water than it does on land. It swims with most of +the body submerged, and dives with perfect ease, remaining long without +coming to the surface to breathe. It makes its nest in burrows in the +banks of streams, breeding once a year about the month of April, and +producing five or six young at a birth. Its food consists of frogs, fish, +freshwater molluscs and crustaceans, as well as mice, rats, musk-rats, +rabbits, and small birds. In common with the other animals of the genus, +it has a very peculiar and disagreeable effluvium, which, according to +Coues, is more powerful, penetrating, and lasting than that of any animal +of the country except the Skunk. It also possesses the courage, ferocity, +and tenacity of life of its allies. When taken young, however, it can be +readily tamed, and lately Minks have been extensively bred in captivity +in America, both for the sake of their fur and for the purpose of using +them in like manner as Ferrets in England, to clear buildings of rats. + +[Illustration: FIG. 268.—The Common Polecat (_Mustela putorius_).] + +The Polecats include four species confined to the northern hemisphere, +the best known of which is the Common Polecat (_M. putorius_, Fig. +268). The Ferret is a domesticated variety of this species, generally of +a yellowish-white colour; whereas the Wild Polecat is dark brown above +and black beneath, the face being variegated with dark brown and white +markings. + +The skull is rough, strongly ridged, and of a far more powerful type than +that of the Stoats, Weasels, or Martens; being in the female much smaller +and lighter than in the male. The fur, which is long, coarse, and of +comparatively small value, changes its colour very little, if at all, at +the different seasons of the year. + +The distribution and habits of this species have been described by +Blasius, the following being an abstract of his account. The Polecat +ranges over the greater part of Europe, reaching northwards into Southern +Sweden, and in Russia to the region of the White Sea. It does not occur +in the extreme South, but is common everywhere throughout Central Europe. +In the Alps it ranges far above the tree-line during the summer, but +retreats in winter to lower ground. In fine weather it lives either in +the open air, in holes, fox-earths, rabbit-warrens, under rocks, or +in wood-stacks, while in winter it seeks the protection of deserted +buildings. During the day it sleeps in its hiding-place, sallying forth +at night to plunder dovecots and hen-houses. It climbs but little, and +shows far less activity than the Marten. It feeds ordinarily on small +mammals, such as rabbits, hamsters, rats, and mice, on such birds as it +can catch, especially poultry and pigeons, and also on snakes, lizards, +frogs, fish, and eggs. Its prey is devoured only in its lair, but, +even though it can carry away but a single victim, it commonly kills +everything that comes in its way, often destroying all the inhabitants of +a hen-house in order to gratify its passion for slaughter. The pairing +time is towards the end of the winter, and the young, from three to +eight in number, are born in April or May, after a period of gestation +of about two months. The young, if taken early, may be easily trained, +like Ferrets, for rabbit catching. The Polecat is very tenacious of life, +and will bear many severe wounds before succumbing; it is also said to +receive with impunity the bite of the adder. Its fetid smell has become +proverbial. + +Four other species of Polecats are known, viz.—The Siberian Polecat +(_M. eversmanni_) of Western and Northern Asia is nearly allied to the +European species, but the head and back are almost white, and the skull +is stouter and more constricted behind the orbits. The Tibetan _M. +larvata_ is distinguished from the last by the presence of a process +connecting the pterygoid with the auditory bulla, and by a difference +in the shape of the upper molar. The American Polecat (_M. nigripes_), +inhabiting the central plateau of the United States, and extending +southwards into Texas, is another closely allied species, although some +zoologists have made it the type of the genus _Cynomyonax_. Finally, +the Mottled Polecat (_M. sarmatica_) is a species sparsely distributed +in Eastern Europe and parts of Western Asia, but common in Southern +Afghanistan. Its skull, although smaller, resembles that of the common +species; but the coloration is very different, all the upper parts being +mottled with large irregular reddish spots on a white ground, and the +under side, limbs, and tail deep shining black. The tail is long. + +The Common Polecat occurs in a fossil condition in the cave-deposits of +Europe. + +[Illustration: FIG. 269.—The Common Weasel (_Mustela vulgaris_).] + +The remaining members of the genus comprise the true Weasels and Stoats, +which are of almost cosmopolitan distribution. In the Common Weasel (_M. +vulgaris_, Fig. 269) the upper parts, outside of limbs and tail, are a +uniform reddish-brown, the under parts pure white. In very cold regions, +both in Europe and America, it turns completely white in winter, but less +regularly and at a lower temperature than the Stoat, from which it is +easily distinguished by its smaller size, and by its wanting the black +end of the tail. The length of the head and body of the male is usually +about 8 inches, that of the tail 2½ inches; the female is smaller. + +This species is pretty generally distributed throughout Europe, Northern +and Central Asia, British North America, and the northern portions of the +United States. It possesses in a full degree all the active, courageous, +and bloodthirsty disposition of the rest of the genus, but its diminutive +size prevents it attacking and destroying any but the smaller mammals +and birds. Mice, rats, voles, moles, and frogs constitute its principal +food. It is generally found on or near the surface of the ground, but it +can not only pursue its prey through very small holes and crevices of +rocks and under dense tangled herbage, but follow it up the stems and +branches of trees, or even into the water, swimming with perfect ease. It +constructs a nest of dried leaves and herbage, placed in a hole in the +ground or a bank or hollow tree, in which it brings up its litter of four +to six (usually five) young ones. The mother will defend her young with +the utmost desperation against any assailant, having been often known to +sacrifice her own life rather than desert them. + +The Stoat or Ermine (_M. erminea_) has nearly the same distribution as +the Weasel, but in Asia it is said to extend into parts of the Kashmir +Himalaya. Its size, as already mentioned, considerably exceeds that +of the Weasel; and its most distinctive feature is the black tip at +the end of the tail, which remains when the rest of the pellage turns +white. The white winter skins from the northern regions of its habitat, +where the fur is thick and close, form the well-known and valuable +ermine of commerce. Remains of the Stoat are found in the Pleistocene +cavern-deposits of Europe. The other species of Weasels are very numerous +and widely distributed. + +_Extinct Mustelines._—A number of European Miocene Carnivores may be +referred to the genus _Mustela_ in its wider sense, and serve to confirm +the propriety of this use of the term. Thus _M. sectoria_ is a species +of somewhat larger size than the Stoat, with _p_ ⁴⁄₄, while in _M. +angustifrons_ the number of premolars is ³⁄₄, and in _M. mustelina_ +⁴⁄₃; the latter species agreeing very closely in size with the Stoat. +The extinct _Plesictis_, in which there are _p_ ⁴⁄₄ and the lower +carnassial has a large inner cusp, is distinguished from _Mustela_ by the +circumstance that the temporal ridges of the skull never unite to form +a sagittal crest. Moreover, the inner tubercular portion of the upper +molar (as in some of the Miocene species of _Mustela_) is shorter in an +antero-posterior direction than the secant outer moiety; and the auditory +bulla is more inflated than in _Mustela_, although it has no septum. +Both these features indicate a decided approximation to the Viverroid +genus _Stenoplesiotis_ (p. 539); and since there are no well-marked +characters of family value by which these two genera can be distinguished +the available evidence points to a transition from the Viverroid to the +Musteloid type. _Mustela larteti_, of the Middle Miocene of France, +should perhaps be referred to _Ictonyx_. + +_Pœcilogale._[512]—This genus has been made for the reception of the +South African _Mustela albinucha_, in which the coloration is similar +to that of _Ictonyx_, but the number of cheek-teeth is usually reduced +to _p_ ²⁄₂, _m_ ¹⁄₁, although there may be a second lower molar. The +auditory bulla is quite flat. + +_Lyncodon._[513]—This name has been proposed for a small Musteline from +Patagonia, with _p_ ²⁄₂, _m_ ¹⁄₁, which Mr. O. Thomas suggests may be +nothing more than an aberrant southern form of _Mustela_ (_Putorius_) +_brasiliensis_. The auditory bulla is more inflated than in the typical +Weasels. This animal is somewhat larger than the Stoat. + +[Illustration: FIG. 270.—The Wolverene (_Gulo luscus_).] + +_Gulo._[514]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ¹⁄₂; total 38. +Crowns of the teeth very stout. Upper molar very much smaller than the +carnassial. Lower carnassial large, with very small talon and no inner +cusp. Third upper incisor unusually large, almost like a canine. The +dentition, though really but a modification of that of the Weasels, +presents a great general resemblance to that of the Hyæna. Palate +prolonged somewhat behind the last molar. Humerus with an entepicondylar +foramen. Vertebræ: C 7, D 15, L 5, S 3, C 15. Body and limbs stoutly +made. Feet large and powerful, subplantigrade, with large, compressed, +much curved, and sharp-pointed claws. Soles of the feet (except the +pads of the toes) covered with thick bristly hairs. Ears very small, +nearly concealed by the fur. Eyes small. Tail short, thick, and bushy. +Fur full, long, and rather coarse. The one species, the Wolverene or +Glutton (_G. luscus_, Fig. 270), an inhabitant of the forest regions +of Northern Europe, Asia, and America, much resembles a small Bear in +appearance. It is a very powerful animal for its size, climbs trees, and +lives on grouse, squirrels, hares, foxes, beavers, reindeer, and is said +to attack even horses and cows. The Wolverene has a curious habit of +stealing and secreting articles of which it can make no possible use, as +is exemplified in the following instance related by Dr. Coues: “A hunter +and his family, having left their lodge unguarded during their absence, +on their return found it completely gutted—the walls were there, but +nothing else. Blankets, guns, kettles, axes, cans, knives, and all the +other paraphernalia of a trapper’s tent had vanished, and the tracks left +by the beast showed who had been the thief. The family set to work, and, +by carefully following up all his paths, recovered, with some trifling +exceptions, the whole of the lost property.” The pairing season occurs in +March, and the female, secure in her burrow, produces her young, four or +five at a birth, in June or July. In defence of these she is exceedingly +bold, and the Indians, according to Coues, “have been heard to say that +they would sooner encounter a she-bear with her cubs than a carcajou (the +Indian name of the glutton) under the same circumstances.” + +Fossil remains of the Wolverene are found in cavern and other Pleistocene +deposits in various parts of Europe. + + +_Suborder_ PINNIPEDIA. + +The Eared-Seals, Walruses, and Seals differ from the rest of the +Carnivora mainly in the structure of their limbs, which are modified +for aquatic progression,—the two proximal segments being very short +and partially enveloped in the general integument of the body; while +the third segment, especially in the hinder extremities, is elongated, +expanded, and webbed. There are always five well-developed digits on +each limb. In the hind limb the two marginal digits (first and fifth) +are stouter and generally longer than the others. The teeth also differ +from those of the more typical Carnivora. The incisors are always fewer +than ³⁄₃. The cheek series consists generally of four premolars and one +molar of very uniform characters, with never more than two roots, and +with conical, more or less compressed, pointed crowns, which may have +accessory cusps, placed before or behind the principal one, but are never +broad and tuberculated; and there is no differentiated carnassial tooth. +The milk-teeth are very small and simple, and are shed or absorbed at a +very early age, usually either before or within a few days after birth. +The brain is relatively large; the cerebral hemispheres being broad in +proportion to their length, with numerous and complex convolutions. There +is a very short cæcum. The kidneys are divided into numerous distinct +lobules. There are no Cowper’s glands. The mammæ are either two or four, +and abdominal in position. No clavicles. Tail always very short. Eyes +very large and exposed, with flat cornea. + +The animals of this group are all aquatic in their mode of life, spending +the greater part of their time in the water, swimming and diving with +great facility, feeding mainly on fish, crustaceans, and other marine +animals, and progressing on land with difficulty. They always come on +shore, however, for the purpose of bringing forth their young. They +are generally marine, but they occasionally ascend large rivers, and +some inhabit inland seas and lakes, as the Caspian and Baikal. Though +not numerous in species, they are widely distributed over the world, +but occur most abundantly on the coasts of lands situated in cold and +temperate zones. The suborder is divisible into three well-marked +families: the _Otariidæ_, Fur-Seals or Sea-Bears, which form a transition +from the Fissiped Carnivora to the Seals; the _Trichechidæ_, containing +the Walrus; and the _Phocidæ_ or typical Seals. + +The resemblances between the skull and other parts of the body of the +Fur Seals and the Ursoid true Carnivora is suggestive of some genetic +relationship between the two groups, and Professor Mivart[515] expresses +the opinion that the one group is the direct descendant of the other. The +same writer goes on to suggest that if the Eared-Seals have been derived +from Bear-like Carnivores this need not necessarily hold good with the +true Seals, which may have had another, and possibly Lutrine, origin. +The presence of an alisphenoid canal in _Ursus_ and the _Otariidæ_, +and its absence in _Lutra_ and the _Phocidæ_, together with other +osteological features, are cited in support of this view; but although +these resemblances and differences are certainly remarkable, yet much +more evidence is required before the hypothesis can be accepted as even +a probable one. It must, moreover, be borne in mind that the true Bears +are a very modern group; and there is a possibility that the Pinnipeds +may prove to have been independently derived from the extinct Carnivora +noticed below under the name of Creodonta. + + +_Family_ OTARIIDÆ. + +When on land the hind feet are turned forwards under the body, and aid +in supporting and moving the trunk as in ordinary mammals. A small +external ear. Testes suspended in a distinct external scrotum. Skull +with postorbital processes, and an alisphenoid canal. Angle of mandible +inflected. Palms and soles of feet naked. + +_Otaria._[516]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ¹⁻²⁄₁; total +34 or 36. First and second upper incisors small, with the summits of +the crowns divided by a deep transverse groove into an anterior and a +posterior cusp of nearly equal height; the third large and canine-like. +Canines large, conical, pointed, recurved. Molars and premolars usually +⁵⁄₅, of which the second, third, and fourth are preceded by milk-teeth +shed a few days after birth; sometimes (as in Fig. 271) a sixth upper +molar (occasionally developed on one side and not the other); all with +similar characters, generally uniradicular; crown moderate, compressed, +pointed, with a single principal cusp, and sometimes a cingulum, and more +or less developed anterior and posterior accessory cusps. Vertebræ: C 7, +D 15, L 5, S 4, C 9-14. Head rounded. Eyes large. Pinna of ear small, +narrow, and pointed. Neck long. Skin of all the feet extended far beyond +the nails and ends of the digits, with a deeply-lobed margin. The nails +small and often quite rudimentary, especially those of the first and +fifth toes of both feet, the best developed and most constant being the +three middle claws of the hind foot, which are elongated, compressed, and +curved. + +[Illustration: FIG. 271.—Skull of _Otaria forsteri_. (From Gray, _Proc. +Zool. Soc._ 1872, p. 660.)] + +The Eared-Seals, commonly called Sea-Bears or Sea-Lions, are widely +distributed, especially in the temperate regions of both hemispheres, +though absent from the coasts of the North Atlantic. As might be +inferred from their power of walking on all fours, they spend more of +their time on shore, and range inland to greater distances, than the +true Seals, especially at the breeding time, though they are obliged +always to return to the water to seek their food. They are gregarious +and polygamous, and the males are usually much larger than the females, +a circumstance which has given rise to some of the confusion existing +in the specific determination of the various members of the genus. Some +of the species possess, in addition to the stiff, close, hairy covering +common to all the group, an exceedingly fine, dense, woolly under fur. +The skins of these, when dressed and deprived of the longer harsh outer +hairs, constitute the “seal-skin” of commerce, so much valued for +wearing apparel, which is not the product of any of the true Seals. +The best-known species are _O. stelleri_, the Northern Sea Lion, the +largest of the genus, from the North Pacific, about 10 feet in length; +_O. jubata_, the Patagonian or Southern Sea Lion (Fig. 272), from the +Falkland Islands and Patagonia; _O. californiana_, from California, +frequently exhibited alive in menageries in Europe; _O. ursina_, the +common Sea-Bear or Fur-Seal of the North Pacific, the skins of which are +imported in immense numbers from the Prybiloff Islands; _O. pusilla_, +from the Cape of Good Hope; _O. forsteri_ and others, from the coasts of +Australia and various islands scattered over the southern hemisphere. +These have been grouped by some zoologists into many genera, founded upon +very trivial modifications of teeth and skull. In a recent memoir Mr. +Beddard[517] concludes that if the genus be split up at all, it should +be divided into _Otaria_, containing only _O. jubata_ (with its numerous +synonyms), and _Arctocephalus_, comprising all the other species. The +latter group is distinguished by the more narrow and pointed nose, the +longer ears, the palate not excavated nor truncated posteriorly, the +presence of a hook-like process to the pterygoids, and by the posterior +border of the nasals extending behind the zygoma. + +[Illustration: FIG. 272.—The Patagonian Sea-Lion (_Otaria jubata_). From +Sclater, _Proc. Zool. Soc._ 1866, p. 80.] + +The following account of _O. ursina_ in the Prybiloff Islands is taken, +with slight verbal alteration, from Nordenskiöld’s _Voyage of the Vega_: +“The Sea-Bears are found year after year during summer at certain parts +of the coast, known as ‘rookeries,’ where, collected in hundreds of +thousands, they pass several months without the least food. The males +or ‘bulls’ come first to the place, most of them in the month of May +or in the beginning of June. The most violent conflicts, often with a +deadly issue for one of the parties, now arise regarding the space of +about a hundred square feet which each bull-seal considers necessary for +his home. The strongest and most successful in fight retain the best +places near the shore; the weaker have to crawl farther up on land, +where the chances of getting a sufficient number of spouses are not +particularly great. The fighting goes on with many feigned attacks and +parades. At first the contest concerns only the proprietorship of the +soil. The attacked, therefore, never follows his opponent beyond the area +he has once taken up, but haughtily lays itself down, when the enemy +has retired, in order to collect strength for a new combat. The animal +in such a case grunts with satisfaction, throws himself on his back, +scratches himself with his fore feet, attends to his toilet, or cools +himself by slowly fanning with one of his hind feet; but he is always on +the alert and ready for a new fight, until he is tired out and meets his +match and is driven farther up from the beach. In the middle of June the +females come up from the sea. At the water’s edge they are received in +a very gallant way by some strong bulls that have succeeded in securing +for themselves places next the shore, and now are bent by fair means or +foul on annexing the females for their harem. But scarcely is the female +that has come up out of the water established with male No. 1 than he +rushes towards a new female on the surface of the water. Male No. 2 now +stretches out his neck and without ceremony lays hold of the female of +No. 1, to be afterwards exposed to a similar trick by No. 3. In such +cases the females are quite passive, never fall out with each other, and +bear with patience the severe wounds they often get when they are pulled +about by the combatants, now in one direction, now in another. All the +females are finally distributed in this way after furious combats among +the males, those of the latter who are nearest the beach getting from +12 to 15 consorts to their share. Soon after landing the females bring +forth their young, which are treated with great indifference, and are +protected by their adopted father only within the limits of the harem. +Next comes the pairing season, and when it has passed there is an end +to the arrangement and distribution into families at first so strictly +maintained. The males, rendered lean by three months’ absolute fasting, +by degrees leave the rookery, which is left in possession of the Walruses +and the young Sea Bears, including a number of young males that have not +ventured to the place before. In the middle of September, when the young +have learned to swim, the place is quite abandoned, with the exception of +single animals that have for some reason remained behind.” + + +_Family_ TRICHECHIDÆ. + +In many characters the single genus representing this family is +intermediate between the _Otariidæ_ and _Phocidæ_, but it has a +completely aberrant dentition. It has no external ears, as in the +_Phocidæ_; but when on land the hind feet are turned forwards and used +in progression, though less completely than in the _Otariidæ_. The upper +canines are developed into immense tusks, which descend a long distance +below the lower jaw. All the other teeth (Fig. 273), including the lower +canines, are much alike, small, simple, and one-rooted, the molars +with flat crowns. The skull is without postorbital process, but has an +alisphenoid canal. + +[Illustration: FIG. 273.—Diagram of the dentition of the Walrus +(_Trichechus rosmarus_). The denticles placed apart from the others are +milk-teeth, and disappear soon after birth. The small teeth in connection +with the jaws frequently persist throughout life.] + +_Trichechus._[518]—Dentition of young: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ and _m_ ⁵⁄₄. +Many of these teeth are, however, lost early or remain through life in +a rudimentary state concealed by the gums. The teeth which are usually +developed functionally are _i_ ¹⁄₀, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ⁰⁄₀; total +18. Vertebræ: C 7, D 14, L 6, S 4, C 12. Head round. Eyes rather small. +Muzzle short and broad, with on each side a group of long, very stiff, +bristly whiskers. The remainder of the hair-covering very short and +adpressed. Tail very rudimentary. Fore feet with subequal toes, carrying +five minute flattened nails. Hind feet with subequal toes, the fifth +slightly the largest, having cutaneous lobes projecting beyond the ends +as in _Otaria_; first and fifth with minute flattened nails; second, +third, and fourth with large, elongated, subcompressed pointed nails. + +_Trichechus_ is the almost universally accepted generic name by which +the Walrus or Morse[519] is known to zoologists, but some confusion has +been introduced into literature by the revival of the nearly obsolete +terms _Rosmarus_ by some authors and _Odobænus_ by others. _T. rosmarus_ +is the name of the species met with in the Arctic seas; that of the +North Pacific, if distinct, is _T. obesus_. The preceding and following +descriptions will apply equally to both. A full-grown male Walrus +measures from 10 to 11 feet from the nose to the end of the very short +tail, and is a heavy, bulky animal, especially thick about the shoulders. +The soles of both fore and hind feet are bare, rough, and warty. The +surface of the skin generally is covered with short, adpressed hair of +a light, yellowish-brown colour, which, on the under parts of the body +and base of the flippers, passes into dark reddish-brown or chestnut. +In old animals the hair becomes more scanty, sometimes almost entirely +disappearing, and the skin shows ample evidence of the rough life and +pugnacious habits of the animal in the innumerable scars with which it is +usually covered. It is everywhere more or less wrinkled, but especially +over the shoulders, where it is thrown into deep and heavy folds. + +[Illustration: FIG. 274.—The Walrus (_Trichechus rosmarus_).] + +The tusks are formidable weapons of defence, but their principal use +seems to be scraping and digging among the sand and shingle for the +molluscs and crustaceans on which the Walrus feeds. They are said also +to aid in climbing up the slippery rocks and ledges of ice on which +so much of the animal’s life is passed. Although this function of the +tusks is affirmed by numerous authors, some of whom appear to have had +opportunities of actual observation, it is explicitly denied by Malmgren. + +Walruses are more or less gregarious in their habits, being met with +generally in companies or herds of various sizes. They are only found +near the coast or on large masses of floating ice, and rarely far out in +the open sea; and, though often moving from one part of their feeding +ground to another, they have no regular seasonal migrations. Their young +are born between the months of April and June, usually but one at a +time, never more than two. Their strong affection for their young, and +their sympathy for each other in times of danger, have been particularly +noticed by all who have had the opportunity of observing them in their +native haunts. When one of their number is wounded, the whole herd +usually join in a concerted and intelligent defence. Although harmless +and inoffensive when not molested, they exhibit considerable fierceness +when attacked, using their great tusks with tremendous effect either on +human enemies who come into too close quarters or on Polar Bears, the +only other adversaries they can meet with in their own natural territory. +Their voice is a loud roaring, and can be heard at a great distance; it +is described by Dr. Kane as “something between the mooing of a cow and +the deepest baying of a mastiff, very round and full, with its bark or +detached notes repeated rather quickly seven or nine times in succession.” + +The principal food of the Walrus consists of bivalved molluscs, +especially _Mya truncata_ and _Saxicava rugosa_, two species very +abundant in the Arctic regions, which it digs up from the mud and sand +in which they lie buried at the bottom of the sea by means of its tusks. +It crushes and removes the shells by the aid of its grinding teeth and +tongue, swallowing only the soft part of the animal. It also feeds on +other molluscs, sand-worms, star-fishes, and shrimps. Portions of various +kinds of algæ or sea-weeds have been found in its stomach, but whether +swallowed intentionally or not is still doubtful. + +The commercial products of the Walrus are its oil, hide (used to +manufacture harness and sole-leather and twisted into tiller ropes), and +tusks. The ivory of the latter is, however, inferior in quality to that +of the Elephant. Its flesh forms an important article of food to the +Eskimo and Tchuktchis. Of the coast tribes of the last-named people the +Walrus forms the chief means of support. “The flesh supplies them with +food, the ivory tusks are made into implements used in the chase and for +other domestic purposes, as well as a affording a valuable article of +barter, and the skin furnishes the material for covering their summer +habitations, harness for their dog-teams, and lines for their fishing +gear” (Scammon). + +Geographically the Walrus is confined to the northern circumpolar +regions of the globe, extending apparently as far north as explorers +have penetrated, but its southern range has been much restricted of late +in consequence of the persecutions of man. On the Atlantic coast of +America it was met with in the sixteenth century as low as the southern +coast of Nova Scotia, and in the last century it was common in the Gulf +of St. Lawrence and on the shores of Labrador. It still inhabits the +coast round Hudson’s Bay, Davis Straits, and Greenland, where, however, +its numbers are daily decreasing. It is not found on the Arctic coast +of America between the 97th and 158th meridians. In Europe occasional +stragglers have reached the British Isles, and it was formerly abundant +on the coasts of Finmark. It is rare in Iceland, but Spitzbergen, Nova +Zembla, and the western part of the north coast of Siberia are still +constant places of resort, in all of which a regular war of extermination +is carried on. The North Pacific, including both sides of Behring’s +Strait, northern Kamschatka, Alaska, and the Pribyloff Islands, are also +the haunts of numerous Walruses, which are isolated from those of the +North Atlantic by the long stretches of coast, both of Siberia and North +America, where they do not occur. The Pacific Walrus appears to be as +large as, if not larger than, that of the Atlantic; its tusks are longer +and more slender, and curved inwards; the whiskers are smaller, and the +muzzle (of the skull) relatively deeper and broader. These and certain +other minor differences have induced some naturalists to consider it +specifically distinct under the name of _Trichechus obesus_. Its habits +appear to be quite similar to those of the Atlantic form. Though formerly +found in immense herds, it is rapidly becoming scarce, as the methods of +destruction used by the American whalers, who have systematically entered +upon its pursuit, are far more certain and deadly than those of the +native Tchuktchis, to whom, as mentioned before, the Walrus long afforded +the principal means of subsistence. + +Fossil remains of Walruses and closely allied animals have been found in +the United States, and in England, Belgium, and France, in deposits of +Pliocene age. + + +_Family_ PHOCIDÆ. + +The true Seals are the most completely adapted for aquatic life of all +the Pinnipeds. When on land the hind limbs are extended behind them and +take no part in progression, which is effected by a series of jumping +movements produced by the muscles of the trunk, in some species aided by +the fore limbs only. The palms and soles of the feet are hairy. There +is no pinna to the ear, and no scrotum, the testes being abdominal. The +upper incisors have simple, pointed crowns, and vary in number in the +different groups. All the forms have well-developed canines and ⁵⁄₅ teeth +of the cheek-series. In those species of which the milk-dentition is +known, there are three milk molars (Fig. 275), which precede the second, +third, and fourth permanent molars; the dentition is therefore _p_ ⁴⁄₄, +_m_ ¹⁄₁, the first premolar having as usual no milk-predecessor. The +skull has no postorbital process and no alisphenoid canal; and the angle +of the mandible is not inflected. The fur is stiff and adpressed, without +woolly under fur. + +Subfamily =Phocinæ=.—Incisors ³⁄₂. All the feet with five well-developed +claws. The toes on the hind feet subequal, the first and fifth not +greatly exceeding the others in length, and with the interdigital +membrane not extending beyond the toes. + +_Halichœrus._[520]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ¹⁄₁; +total 34. Crowns of molars large, simple, conical, recurved, slightly +compressed, with sharp anterior and posterior edges, but without +accessory cusps, except sometimes in the two hinder ones of the lower +jaw. With the exception of the last one or two in the upper jaw and the +last in the lower jaw they are all uniradicular. Vertebræ: C 7, D 15, L +5, S 4, C 14. + +One species, _H. grypus_, the Gray Seal of the coasts of Scandinavia and +the British Isles (see page 604.) + +[Illustration: FIG. 275.—Upper permanent and deciduous dentition of the +Greenland Seal (_Phoca grœnlandica_). The first and second deciduous +incisors are already absorbed.] + +_Phoca._[521]—Dental formula as the last. Teeth smaller and more pointed. +Molars (Figs. 275 and 276) with two roots (except the first in each jaw); +and their crowns with accessory cusps. Vertebræ: C 7, D 15, L 5, S 4, +C 12-15. Head round and short. Fore feet short, with five very strong, +subcompressed, slightly curved, rather sharp claws, subequal in length. +On the hind feet the claws much narrower and less curved. The species of +this genus are widely distributed throughout the northern hemisphere, and +include _P. barbata_, the Bearded Seal; _P. grœnlandica_, the Greenland +Seal; _P. vitulina_, the Common Seal (Fig. 277); and _P. hispida_, the +Ringed Seal of the North Atlantic; _P. caspica_, from the Caspian and +Aral Seas; and _P. sibirica_, from Lake Baikal. + +[Illustration: FIG. 276.—Skull of Common Seal, showing form of teeth.] + +Although the members of this subfamily swim and dive with the greatest +ease, often remaining as much as a quarter of an hour or more below the +surface, and are dependent for their sustenance entirely on living prey +captured in the water, yet they frequently resort to sandy beaches, +rocks, or ice-floes, either to sleep or to bask in the sun, and +especially for the purpose of bringing forth their young. The latter +appears to be the universal habit, and, strange as it may seem, the +young seals—of some species at least—take to the water at first very +reluctantly, and have actually to be taught to swim by their parents. The +number of young produced is usually one annually, though occasionally +two. They are at first covered with a coat of very thick, soft, nearly +white fur, and until it falls off they do not usually enter the water. +This occurs in the Greenland and Gray Seal when from two to three weeks +old, but in the Common Seal apparently much earlier. One of this species +born in the London Zoological Gardens had shed its infantile woolly +coat and was swimming and diving about in its pond within three hours +after its birth. The movements of the true Seals upon the ground or ice +are very different from those of the Eared-Seals. Thus the hinder limbs +(by which mainly they propel themselves through the water) are on land +always perfectly passive, stretched backwards, with the soles of the +feet applied to each other, and often raised to avoid contact with the +ground. Sometimes the fore limbs are equally passive, being placed close +to the sides of the body, and motion is then effected by a shuffling or +wriggling action produced by the muscles of the trunk. When, however, +there is any necessity for a more rapid mode of progression the animals +use the fore paws, either alternately or simultaneously, pressing the +palmar surface on the ground and lifting and dragging the body forwards +in a succession of short jumps. In this way they manage to move so fast +that a man has to step out beyond a walk to keep up with them; but such +rapid action costs considerable effort, and they very soon become heated +and exhausted. These various modes of progression appear to be common to +all species so far as has been observed. + +Most kinds of Seals are gregarious and congregate, especially at the +breeding season, in immense herds. Such is the habit of the Greenland +Seal (_Phoca grœnlandica_), which resorts in the spring to the ice-floes +of the North Sea, around Jan Mayen Island, where about 200,000 are +killed annually by the crews of the Scotch, Dutch, and Norwegian sealing +vessels. Others, like the Common Seal of the British islands (_P. +vitulina_), though having a wide geographical range, are never met with +in such large numbers or far away from land. This species is stationary +all the year round, but some have a regular season of migration, moving +south in winter and north in summer. They are usually harmless, timid, +inoffensive animals, though, being polygamous, the old males often fight +desperately with each other, their skins being frequently found covered +with wounds and scars. They are greatly attached to their young, and +remarkably docile and easily trained when in captivity; indeed, although +there would seem little in the structure or habits of the Seal to fit +it by nature to be a companion of man, yet there is perhaps no wild +animal which attaches itself so readily to the person who takes care +of and feeds it. Seals appear to have much curiosity, and it is a very +old and apparently well-attested observation that they are strongly +attracted by musical sounds. Their sense of smell is very acute, and +their voice varies from a harsh bark or grunt to a plaintive bleat. +Seals feed chiefly on fish, of which they consume enormous quantities; +some, however, subsist largely on crustaceans, especially species +of _Gammarus_, which swarm in the northern seas, also on molluscs, +echinoderms, and even occasionally sea-birds, which they seize when +swimming or floating on the water. + +[Illustration: FIG. 277.—The Common Seal (_Phoca vitulina_).] + +Although the true Seals do not possess the beautiful under fur +(“seal-skin” of the furriers) which makes the skin of the Sea-Bears so +precious, yet their hides are still sufficiently valuable as articles of +commerce, together with the oil yielded by their fat, to subject them to +a devastating persecution, by which their numbers are being continually +diminished. + +Two species of seals only are met with regularly on the British +coasts, the Common Seal and the Gray Seal. The former (Fig. 277) is +a constant resident in all suitable localities round the Scottish, +Irish, and English coasts, from which it has not been driven away by +the molestations of man. Although, naturally, the most secluded and +out-of-the-way spots are selected as their habitual dwelling-places, +there are few localities where they may not be occasionally met with. +Within the writers’ knowledge one was seen not many years ago lying on +the shingly beach at so populous a place as Brighton, and another was +caught in the river Welland, near Stamford, 30 miles from the sea. They +frequent bays, inlets, and estuaries, and are often seen on sandbanks +or mudflats left dry at low tide, and, unlike some of their congeners, +are not found on the ice-floes of the open sea, nor, though gregarious, +are very large numbers ever seen in one spot. The young are produced +at the end of May or beginning of June. They feed chiefly on fish, and +the destruction they occasion among salmon is well known to Scottish +fishermen. The Common Seal is widely distributed, being found not only on +the European and American coasts bordering the Atlantic Ocean, but also +in the North Pacific. It is from 4 to 5 feet in length, and variable in +colour, though usually yellowish-gray, with irregular spots of dark brown +or black above and yellowish-white beneath. The Gray Seal (_Halichœrus +grypus_) is of considerably larger size, the males attaining when fully +adult a length of 8 feet from nose to end of hind feet. It is of a +yellowish-gray colour, lighter beneath, and with dark gray spots or +blotches, but, like most other Seals, is liable to great variations of +colour according to age. This species appears to be restricted to the +North Atlantic, having been rarely seen on the American coasts, but not +farther south than Nova Scotia; it is chiefly met with on the coasts of +Ireland, England, Scotland, Norway, and Sweden, including the Baltic +and Gulf of Bothnia, and Iceland, though it does not appear to range +farther north. It is apparently not migratory, and its favourite breeding +places are rocky islands; the young being born in the end of September or +beginning of October. + +Subfamily =Monachinæ=.—Incisors ²⁄₂. Cheek-teeth two-rooted, except the +first. On the hind feet the first and fifth toes greatly exceeding the +others in length, with nails rudimentary or absent. + +_Monachus._[522]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ¹⁄₁; total 32. +Crowns of molars strong, conical, compressed, hollowed on the inner side, +with a strongly marked lobed cingulum, especially on the inner side, and +slightly developed accessory cusps before and behind. The first and last +upper and the first lower molar considerably smaller than the others. +Vertebræ: C 7, D 15, L 5, S 2, C 11. All the nails of both fore and +hind feet very small and rudimentary. One species, _M. albiventer_, the +Monk-Seal of the Mediterranean and adjacent parts of the Atlantic. + +The other genera[523] of this section have the same dental formula, but +are distinguished by the characters of the cheek-teeth and the feet. They +are all inhabitants of the shores of the southern hemisphere. + +_Ogmorhinus._[524]—All the teeth of the cheek-series with three distinct +pointed cusps, deeply separated from each other; of these the middle or +principal cusp is largest and slightly recurved; the other two (anterior +and posterior) are nearly equal in size, and have their apices directed +towards the middle one. Skull much elongated. One species, _O. leptonyx_, +the Sea-Leopard, widely distributed in the Antarctic and southern +temperate seas. + +_Lobodon._[525]—Cheek-teeth with much-compressed elongated crowns and a +principal recurved cusp, rounded and somewhat bulbous at the apex, and +one anterior, and one, two, or three posterior, very distinct accessory +cusps. One species, _L. carcinophaga_. + +_Pœcilophoca._[526]—Cheek-teeth small, with simple, subcompressed, +conical crowns, having a broad cingulum, but no distinct accessory cusps. +One species, _P. weddelli_. + +_Ommatophoca._[527]—All the teeth very small; those of the cheek-series +with pointed recurved crowns, and small posterior and still less +developed anterior accessory cusps. Orbits very large. Nails quite +rudimentary on front, and absent on hind feet. The skull bears a +considerable resemblance to that of the members of the next subfamily, +towards which it may form a transition. There is one species, _O. rossi_, +of which very little is known. + +Subfamily =Cystophorinsæ=.—Incisors ²⁄₁. Teeth of cheek-series generally +one-rooted. Nose of males with an appendage capable of being inflated. +First and fifth toes of hind feet greatly exceeding the others in length, +with prolonged cutaneous lobes, and rudimentary or no nails. + +_Cystophora._[528]—Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ¹⁄₁; total +30. The last molar has generally two distinct roots. Beneath the skin +over the face of the adult male, and connected with the nostrils, is a +sac which, when inflated, forms a kind of hood covering the upper part of +the head. Nails present, though small, on the hind feet. One species, _C. +cristata_, the Hooded or Bladder-Nose Seal of the Polar Seas. + +_Macrorhinus._[529]—Dentition as the last, but cheek-teeth of simpler +character, and all one-rooted. All the teeth, except the canines, very +small relatively to the size of the animal. Hind feet without nails. +Vertebræ: C 7, D 15, L 5, S 3, C 11. Nose of adult male produced into a +short tubular proboscis, ordinarily flaccid, but capable of dilatation +and elongation under excitement. One species, _M. leoninus_, the +Elephant Seal, or Sea-Elephant of the whalers, the largest of the whole +family, attaining the length of nearly 20 feet. Formerly abundant in the +Antarctic Seas, and also found on the coast of California. + +_Extinct Seals._—Remains of animals of this group have been found in late +Miocene and Pliocene strata in Europe and America, the most abundant and +best-preserved being those of the Pliocene Antwerp Crag, the subject of +an illustrated monograph by Van Beneden. Nothing has, however, yet been +discovered which throws any light upon the origin of the group, since +all the extinct forms at present known come within the definition of +the existing families; and, though annectant forms between these occur, +there are as yet no transitions to a more generalised type of mammal. +Indeed, all those of which the characters are best known belong to the +completely developed Phocine or Trichechine, and not to the Otariine, +type. The typical genus _Phoca_ occurs in the Antwerp Crag, while remains +of Seals provisionally referred to this genus are found in the Pliocene +of the Crimea and the Miocene of Malta and Virginia. Of the other +Antwerp forms _Callophoca_ is said to be allied to _Phoca grœnlandica_, +_Platyphoca_ to _Phoca barbata_, _Phocanella_ to _Phoca foetida_, +_Gryphoca_ to _Halichœrus_, _Palæophoca_ and _Monatherium_ to _Monachus_, +and _Mesotaria_ to _Cystophora_; while _Prophoca_ does not appear to +come very close to any existing form. It should be observed that it is +extremely doubtful whether all these fossil Seals are really entitled to +generic distinction. + + _Bibliography of Pinnipedia._—J. A. Allen, _History of North + American Pinnipeds_, 1880; St. George Mivart, “Notes on the + Pinnipedia,” _Proc. Zool. Soc._ 1885, p. 484; P. J. Van + Beneden, _Ossements fossiles d’Anvers_, in the _Mém. Acad. Roy. + d. Belgique_. + + +_Suborder_ CREODONTA. + +The discovery of fossil remains in Eocene and early Miocene formations +both in Europe and North America shows that numerous species of +terrestrial carnivorous animals existed upon the earth during those +periods which cannot be referred to either of the sections into which +the order has now become broken up. By some zoologists these have been +supposed to be Marsupials, or at least to show transitional characters +between the Metatherian and Eutherian subclasses. By others they are +looked upon as belonging altogether to the latter group, and as the +common ancestors of existing Carnivores and Insectivores, or perhaps +rather as descendants or relatives of such common ancestors, retaining +more of the generalised characters than any of the existing species. They +shade off almost insensibly into numerous other forms less distinctly +carnivorous, to the whole of which, including the modern Insectivora, +Cope (to whom we are indebted for much of our knowledge of the American +extinct species) gives the name of BUNOTHERIA, those more specially +related to the existing Carnivora forming the suborder Creodonta. These +are instances, however, in which the application of the principles of +classification adopted in the case of existing species, of which the +entire structure is known, and which have become divided into isolated +groups by the extinction of intermediate forms, is almost impossible. +If the generally accepted view of evolution is true, and the extreme +modifications pass insensibly into each other by minute gradations (a +view the palæontological proof of which becomes strengthened by every +fresh discovery), there must be many of these extinct forms which cannot +be assigned to definitely characterised groups. There are, however, some +which stand out prominently from the others as formed on distinct types, +having no exact representatives at present living on the earth. + +[Illustration: FIG. 278.—Anterior portion of the skull of _Hyænodon +leptorhynchus_. (After Filhol.)] + +The more typical Creodonts appear, however, to be so closely related to +the true Carnivora through the extinct _Miacidæ_ (p. 539), that it is on +the whole advisable to regard them as representing a distinct suborder +of Carnivora. In the strong development of the canines (Fig. 278) they +are distinguished from the modern Insectivora; and they also differ from +the latter and resemble the true Carnivores in the form of the incisors, +the second one in the lower jaw (when three are present) being thrust +up above the level of the other two in the manner obtaining in most of +the modern Carnivora. Some of the most generalised forms included in the +present group approximate so closely to the Condylarthrous Ungulates as +to indicate that both groups have probably had a common origin. + +The Creodonta as a whole are characterised by the small size of the +brain, the absence of a single differentiated carnassial tooth, and the +triangular form or secant character of their upper molars. In the carpus +the scaphoid and lunar were usually distinct; the femur has a third +trochanter; the upper or tibial surface of the astragalus usually wants +the groove found in modern Carnivores: and the feet were plantigrade. The +curious resemblance of the molars of many of these forms to those of the +Marsupials may indicate a genetic relationship between the two groups; +but, on the other hand, the presence of a full set of milk-teeth and the +absence of palatal vacuities, or of an inflection of the angle of the +mandible, sharply distinguishes them from that order. Space permits of a +notice only of the more interesting forms. + +_Hyænodontidæ._—This family is taken to include some of the more +specialised types, such as the European and American _Hyænodon_ and +_Oxhyæna_ and the European _Pterodon_. In _Hyænodon_ (Fig. 278) the +dental formula is _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₃; the fourth premolar +above and the first true molar below being formed upon the “carnassial” +plan, but the teeth behind these, instead of being tuberculated as in all +existing Carnivora, repeat the characters of the carnassial, and also +increase in size, especially in the lower jaw, from before backwards. +The last lower molar differs from the two preceding teeth, and is very +like the carnassial of _Felis_. The scaphoid and lunar of the carpus +were fused together. Some species, as _H. leptorhynchus_, were as large +as a Wolf, while others did not exceed a Fox in size. _Pterodon_ is +readily distinguished by having _m_ ³⁄₃, by the larger size of the inner +tubercles of the upper molars, and the similarity in the form of the +three lower molars. In some species there were only two upper incisors, +and the first lower premolar may be wanting. _Oxhyæna_ is a specialised +form with _i_ ²⁻³⁄₀, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₂, and a very long +mandibular symphysis. + +_Proviverridæ._—The European and American genus _Proviverra_ +(_Cynohyænodon_ or _Stypolophus_) may be regarded as representing a +second family. The dental formula in this genus is the typical _i_ +³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃, the upper molars have a large inner +tubercle, while the lower molars are differentiated into a blade and +talon, the blade having a large inner cusp. The upper teeth closely +resemble the molars of _Dasyurus_, while the lower molars are like the +lower carnassial of _Cynodictis_ and _Viverra_; and thus indicate how the +Creodonts may have passed into the true Carnivores through the extinct +_Miacidæ_. + +[Illustration: FIG. 279.—The three right upper molars of _Arctocyon +dueli_ (_a_), and the second of _A. gervaisi_ (_b_); from the lowest +Eocene of Rheims. _pr_, protocone; _pa_, paracone; _me_, metacone; _hy_, +hypocone; _ml_, metaconule; _pl_, paraconule. (From Osborn.)] + +_Arctocyonidæ and Mesonychidæ._—The first of these families is +represented by _Arctocyon primævus_, one of the oldest known Tertiary +mammals, from the lowest Eocene beds of La Fère, department of Aisne, +France, and also by other species from corresponding beds at Rheims. The +dental formula is _i_ ³⁄₃, _c_ ¹⁄₁, _p_?⁄₃₋₄, _m_ ³⁄₃. The upper molars +(Fig. 279) are tritubercular, with an incipient postero-internal column +(hypocone); the lower are quadritubercular; and the premolars simple. +The typical species was of large size, but the two of which the teeth +are figured were considerably smaller. In the American _Mesonyx_ the +dental formula was the typical one, the jaws were comparatively short, +the mandibular symphysis was elongated, the cheek-teeth were of simple +structure, and resembled the premolars of many of the true Carnivora, +and the astragalus had a grooved tibial surface and distinct distal +facets for the cuboid and navicular, resembling in the latter respect the +corresponding bone of a Perissodactyle Ungulate. The terminal phalanges +had deeply fissured extremities, and are said to be more like those of +Rodents than true Carnivores. _Mesonyx ossifragus_ was larger than a +Grizzly Bear. _Amblyctonus_, of the same deposits, differs by the smooth +tibial face of the astragalus and the development of an anterior cusp to +the lower molars. + + + + +CHAPTER XII + +THE ORDER INSECTIVORA + + +[Illustration: FIG. 280.—Right lateral aspect of the anterior portion of +the cranium of _Erinaceus collaris_. Enlarged. (From Dobson, _Proc. Zool. +Soc._ 1881, p. 403.)] + +The Insectivora comprise a number of comparatively small mammals, +generally of terrestrial, although rarely of arboreal or aquatic habits, +and presenting the following common features. They are unguiculate, and +have plantigrade or subplantigrade, and generally pentadactylate feet, in +which the pollex and hallux are not opposable to the other digits. They +are diphyodont and heterodont, and the teeth are rooted. The molars are +studded with sharp cusps, the crowns of the upper molars being either +quadrangular or triangular; there are never less than two incisors in +either side of the mandible; and in many cases the incisors, canines, and +anterior premolars are not clearly differentiated from one another (Fig. +280); the canines being usually weak. Clavicles are present, except in +_Potamogale_. The body is clothed with fur or protected by an armature +of spines; the testes are inguinal or placed near the kidneys, and are +not received into a scrotum; the penis is pendent or suspended from the +wall of the abdomen; the uterus is two-horned and with or without a +distinct corpus uteri; the placenta is discoidal and deciduate; and the +smooth cerebral hemispheres do not extend backwards over the cerebellum +(Fig. 281). The projection of the muzzle far beyond the extremity +of the lower jaw is a very general feature. The humerus generally +has an entepicondylar foramen. Certain forms, such as _Talpa_ and +_Galeopithecus_, are unique among mammals in having ossified intercentra +in the dorso-lumbar region of the vertebral column. + +Representatives of this order are found throughout the temperate and +tropical parts of both hemispheres (except South America and Australia), +and exhibit much variety both in organisation and in habits. With the +exception of the _Tupaiidæ_, all are nocturnal; the greater number +are cursorial, but some (_Talpa_, _Chrysochloris_, _Oryzorictes_) are +fossorial; some (_Potamogale_, _Nectogale_, _Myogale_) are natatorial, +and a few (_Tupaiidæ_) arboreal; while the species of the aberrant +genus _Galeopithecus_ glide through the air like the Flying Squirrels. +To the great majority the term insectivorous is strictly applicable, +_Galeopithecus_ alone being phytophagous; while _Potamogale_ is said to +feed on fish, and the different species of Moles live chiefly on worms. +The general organisation of the Insectivora indicates a very low type, +and were it not for the specialised character of their placentation and +the tendency to lose the differentiated characters of the anterior teeth +they might be regarded as closely allied to the ancestral type of many of +the heterodont mammals. The strongly marked distinction of the canines +from the incisors and anterior premolars in the Mesozoic and most of +the Tertiary mammals (excepting some of the Ungulates) points, however, +very decidedly to the conclusion that the want of definition between +these teeth in many of the modern Insectivora is an acquired feature. +Fossil forms apparently indicate a relationship on the one hand with the +Creodont Carnivora, and on the other with the Lemuroid Primates; indeed +it is in some instances impossible to say whether extinct genera are +really Insectivores or Lemuroids. + +[Illustration: FIG. 281.—Upper surface of the brain of _Tupaia +ferruginea_. (From Garrod, _Proc. Zool. Soc._ 1879, p. 304.)] + +In most Insectivora the cranial cavity is of small relative size, and +in none is the brain-case elevated to any considerable extent above the +facial line. The facial part of the skull is generally much produced, +and the premaxillary and nasal bones are well developed. The zygomatic +arch is usually slender or deficient, the latter being the case in most +of the species; and postorbital processes of the frontals are found only +in the _Galeopithecidæ_, _Tupaiidæ_, and _Macroscelididæ_. The number +of dorsal vertebræ varies from 13 in _Talpa_ to 19 in _Centetes_; that +of the lumbar from 3 in _Chrysochloris_ to 6 in _Talpa_ and _Sorex_; +and of the caudal from the rudimentary series of 8 in _Centetes_ to the +40 or more of _Microgale_. Not less variable are the characters of the +vertebræ themselves; the spinous processes often being very long in one +and short in another species of the same genus. In the _Soricidæ_ and +_Myogale_ the neural arches of the cervical vertebræ are very slender. +In the _Soricidæ_ and _Gymnura_ the four anterior vertebræ develop large +single hypapophyses. In _Galeopithecus_ the centrum of each vertebra +supports posteriorly a pair of intercentral ossifications; while in +_Erinaceus_, _Myogale_, and _Talpa_ small oval ossicles are found on +the inferior surfaces of the lumbar interspaces. In _Erinaceus_, owing +to the thickness of the neural cord in the cervical region and its +abrupt termination, the diameter of the neural canal in the cervical +and first two dorsal vertebræ greatly exceeds that of any of the +succeeding vertebræ. The sternum is variable, but generally narrow, +bilobate in front, and divided into segments. The pectoral girdle +presents some remarkable adaptive modifications, most fully expressed +in _Talpa_, having relation to the use of the fore limbs in burrowing; +but in the Golden Moles (_Chrysochloris_) the forearm and manus alone +become specially modified for this purpose. In _Galeopithecus_ and +_Macroscelides_ the bones of the forearm (radius and ulna) are distally +united. The manus has generally five digits, but in _Rhynchocyon_ and +in one species of _Oryzorictes_ the pollex is wanting, while in the +true Moles it is extremely modified. The femur has, in most species, +a prominent ridge below the greater trochanter representing a third +trochanter. In _Galeopithecus_, _Tupaia_, _Centetes_, _Hemicentetes_, +_Ericulus_, and _Solenodon_ the tibia and fibula are distinct, but in all +the other genera more or less united together. The pes usually possesses +five digits (rarely four by reduction of the hallux); and in some forms, +as in the leaping species (_Macroscelides_, _Rhynchocyon_), the tarsal +bones are greatly elongated. The form of the pelvis, and especially of +the symphysis pubis, varies within certain limits; and these differences +have been proposed by Leche as a basis for the classification of the +families. Thus in the _Galeopithecidæ_, _Tupaiidæ_, and _Macroscelididæ_ +there is a long symphysis; in the _Erinaceidæ_, _Centetidæ_, and +_Potamogalidæ_ the symphysis is short; and in the _Soricidæ_, _Talpidæ_, +and _Chrysochloridæ_ there is none. + +Space does not admit of attempting a sketch of the modifications of the +muscular system, which will be found fully described in Dr. Dobson’s +_Monograph_, referred to in the bibliography. As to the nervous system, +it has been already mentioned that the brain throughout the order +presents a low type of organisation; in none of the members do the +cerebral hemispheres present any trace of convolutions, nor do they +extend backwards so as to cover the cerebellum, while the olfactory +lobes are large and project in front, and the corpus callosum is short +and thin. In the Hedgehogs (_Erinaceus_) the spinal column ends abruptly +opposite the third or fourth dorsal vertebra in a slender filament, +and the dorsal and lumbar nerves, given off in front of this point, +are carried backwards in two compressed bundles occupying the suddenly +narrowed spinal canal as far as the sacrum. + +Owing to the similarity in the character of the food, the truly +insectivorous species, forming more than nine-tenths of the order, +present little variety in the structure of their digestive organs. Except +in _Galeopithecus_ the stomach is a simple, thin-walled sac; but in some, +as in _Centetes_ and allied genera, the pyloric and œsophageal openings +are very close together. The intestinal canal has much the same calibre +throughout, and varies from three (in the Shrews) to twelve times (in +the Hedgehogs) the length of the head and body. In the arboreal genera, +_Galeopithecus_ and _Tupaia_, as well as in the _Macroscelididæ_, all of +which probably feed in part on vegetable substances, most of the species +possess a cæcum. The liver is deeply divided into lobes, the right and +left lateral being cut off by deep fissures; and both the caudate and +Spigelian lobes being generally well developed. The gall-bladder, which +is usually large and globular, is placed on the middle of the posterior +surface of the right central lobe. + +In most of the members of the order (_Soricidæ_, _Centetidæ_, +_Chrysochloridæ_) the penis is capable of being more or less completely +retracted within the fold of integument surrounding the anus; in some +(_Galeopithecidæ_, _Talpidæ_) it is pendent in front of the anus; while +in others (_Macroscelididæ_, _Erinaceidæ_, _Solenodontidæ_) it is +carried forwards and suspended from the abdominal wall. In the subfamily +_Centetinæ_ and _Chrysochloris_ the testes lie immediately behind the +kidneys, but in others more or less within the pelvis. During the rutting +season they become greatly enlarged, forming protrusions in the inguinal +region. Except in _Rhynchocyon_ the uterine cornua are long and open +into a short corpus uteri, which in many species (_Soricidæ_, _Talpidæ_, +_Centetidæ_, _Chrysochloridæ_) is not separated from the vagina by a +distinct os uteri. With the exception of _Galeopithecus_ all Insectivora +appear to be multiparous, the number of young at a birth varying from two +to eight in _Erinaceus_, and from twelve to twenty in _Centetes_. The +position of the mammary glands and the number of the teats vary greatly. +Thus in _Galeopithecus_ there are two pairs of axillary teats, and in +_Solenodon_ a single post-inguinal pair; but in most species they range +from the thorax to the abdomen, varying from two pairs in _Gymnura_ to +twelve in _Centetes_. In _Chrysochloris_ the thoracic and inguinal teats +are lodged in deep cup-shaped depressions. + +Odoriferous glands exist in many species. In most Shrews these glands +occur on the sides of the body at a short distance behind the axilla, +and their exudation is probably protective, since few carnivorous +animals will eat the dead bodies of these creatures. In both species of +_Gymnura_ and in _Potamogale_ large pouches are situated on either side +of the rectum and discharge their secretions by ducts, opening in the +first-named genus in front of, and in the latter within the margin of the +anus. In _Centetes_ the ducts of similarly situated racemose glands open +by pores at the bottom of deep pits placed at either side of the anus. + +The integument is thin, but in many species is lined by a muscular coat, +which is probably more developed in the Hedgehogs (_Erinaceidæ_) than in +any other mammal. In this family and the _Centetidæ_ most of the species +are protected by spines implanted in the panniculus carnosus muscle, and +more or less replacing the fur of the upper surface of the body. + +The order is usually divided into two suborders, but the very aberrant +genus which constitutes the first might well be raised to ordinal rank. +It has little in common with the true Insectivora, but as it certainly +belongs to no other of the recognised mammalian orders it is retained +among them chiefly to avoid the inconvenience of increasing the number of +ordinal divisions for the sake of a single isolated form. + + +_Suborder_ DERMOPTERA. + +Upper and lower incisors compressed, multicuspidate, the lower deeply +pectinated; fore and hind limbs connected by a broad integumentary +expansion forming a parachute. + + +_Family_ GALEOPITHECIDÆ. + +In addition to the characters given under the head of the suborder it may +be mentioned that the orbit is nearly surrounded by bone, the zygomatic +arches are well developed, the tympanic forms a bulla, the ulna is +distally united with the radius, the tibia and fibula are distinct, the +pubic symphysis is long, the penis is pendent, the testes are received +into inguinal pouches, the mammæ are axillary, the uterus is two-horned, +and there is a large cæcum. + +_Galeopithecus._[530]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃; +total 34. Second upper incisor and canine with two roots. Two species—_G. +volans_ and _G. philippinensis_. The former, which is distinguished +from the latter by the form of the upper incisors, has a total length +of nearly 2 feet. The long and slender limbs are connected by a broad +integumentary expansion extending outwards from the sides of the neck +and body, and forming also a web between the fingers and toes as far as +the base of the claws (Fig. 282); the hind limbs are further connected by +a similar expansion passing outwards along the back of the feet to the +base of the claws, and, inwardly, involving the long tail to the tip, +forming a true interfemoral membrane, as in the Bats. + +The two species of Flying Lemurs, as the representatives of this genus +are commonly but erroneously called, live in the forests of the Malay +Peninsula, Sumatra, Borneo, and the Philippine Islands, where they feed +chiefly on the leaves and fruits of trees. Their habits are nocturnal, +and during the daytime they cling to the trunks or limbs of trees, head +downwards, in a state of repose. With the approach of night their season +of activity commences, when they may be seen gliding from tree to tree +supported on their cutaneous parachute, and they have been observed to +traverse in this way a space of 70 yards with a descent of only about one +in five. + +[Illustration: FIG. 282.—Feet of _Galeopithecus philippinensis_.] + +_Galeopithecus_ was referred by some of the older zoologists and +anatomists to the Bats, and by others to the Lemurs, but Professor +Peters’s view, that it belongs to neither of these orders, and should be +considered an aberrant Insectivore, has been very generally accepted, +although, as mentioned above, the association is by no means a close one. +Besides differing from the Bats in the form of the anterior limbs and of +the double-rooted outer incisor and canine, it also contrasts strongly +with them in the presence of a large sacculated cæcum, and in the great +length of the colon, which is so remarkably short in all the Chiroptera. +From the Lemurs, on the other hand, the form of the brain, the characters +of the teeth, the structure of the skull, and the deciduate discoidal +placenta completely separate it. In a recent elaborate memoir on the +myology and affinities of _Galeopithecus_ Dr. Leche[531] considers that +we have in this genus an indication of the mode in which the Insectivora +were modified into the Chiroptera, although it is completely off the +direct line of descent. The deeply pectinated crowns of the lower +incisors of _Galeopithecus_ are quite unique in the class, and the only +approach to the double-rooted canine, except in _Erinaceus_ and _Talpa_, +is found among the Marsupials in _Perameles_, where the root of the +canine is grooved. + + +_Suborder_ INSECTIVORA VERA. + +Upper and lower incisors conical, unicuspidate or with basal cusps only, +the lower not pectinated; limbs free, formed for terrestrial progression. + +The following table gives a key to the distinctive characters of the +existing families:— + + I. Upper molars broad, multicuspidate, with more or less + well-defined W-shaped crowns. + + A. Symphysis pubis long; generally a cæcum; cerebral cavity + comparatively large. + + _a._ Orbit encircled by bone; metatarsus moderate; arboreal. + _Tupaiidæ_. + + _b._ Orbit not encircled by bone; metatarsus greatly elongated; + terrestrial. _Macroscelididæ._ + + B. Symphysis pubis short or none; no cæcum; cerebral cavity + small; skull without postorbital processes. + + _a._ First and second upper molars with a central fifth cusp. + + _a′._ Tympanic annular, not forming a bulla. _Erinaceidæ._ + + _b._ No central fifth cusp to upper molars. + + _a′._ Tympanic annular, not forming a bulla; no zygomatic + arch. _Soricidæ._ + + _b′._ Tympanic forming a bulla; zygomatic arch developed. + _Talpidæ._ + + II. Upper molars narrow, with V-shaped crowns. + + _a′._ Tympanic annular, not forming a bulla; zygomatic + arch imperfect. + + _a″._ No clavicles. _Potamogalidæ._ + + _b″._ Clavicles well developed. + + _a‴._ Skull constricted between the orbits; + penis suspended. _Solenodontidæ._ + + _b‴._ Skull not constricted; penis pendent, + retractile. _Centetidæ._ + + _b′._ Tympanic forming a bulla; zygomatic arch well + developed. _Chrysochloridæ._ + +The second section, in which the molars are of the primitive +tritubercular type, should probably be regarded as containing the most +generalised representatives of the order; and it is noteworthy that the +whole of them are confined to Africa, Madagascar, and the West Indies, +whereas most of the first section are widely distributed over the +Palæarctic and Oriental regions. None of the existing families of the +second section are known in a fossil condition, although it is suggested +that the extinct _Leptictidæ_ includes allied types. + + +_Family_ TUPAIIDÆ. + +Skull with comparatively large brain-case, orbit surrounded by bone, +well-developed zygomatic arch, perforated jugal, and a tympanic bulla. +Upper molar broad, with cusps arranged in a W. Pubic symphysis long; +radius and ulna, and tibia and fibula separate; metatarsus only slightly +longer than tarsus. Usually a short cæcum. Habits arboreal and diurnal. +Confined to the Oriental region. + +[Illustration: FIG. 283.—The Pentailed Tree-Shrew (_Ptilocercus lowi_). +From Gray, _Proc. Zool. Soc._ 1848. ½ natural size.] + +_Tupaia._[532]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total +38. Feet naked beneath, the sole furnished with projecting pads; claws +moderate, curved, and sharp; head pointed; ears rounded; tail bushy, +distichous, with short hair below. The Tree-Shrews, of which there are +some nine species, are found in India, Burma, the Malay Peninsula, +the Nicobars, Sumatra, Java, and Borneo. The species closely resemble +one another, differing chiefly in size and in the colour and length of +the fur. Their general appearance is very Squirrel-like. Their food +consists of insects and fruit, which they usually seek in the trees, but +also occasionally on the ground. When feeding they often sit on their +haunches, holding the food, after the manner of Squirrels, between their +forepaws. + +_Ptilocercus._[533]—Represented only by the Pentailed Tree-Shrew (_P. +lowi_, Fig. 283) of Borneo, in which the tail is of extraordinary length, +with the proximal two-thirds naked, and the remaining third furnished +with a bilateral fringe of long hairs, from which the genus takes its +name. + +_Extinct Genera._—An Insectivore from the Middle Miocene of France, +described as _Lantanotherium_, is said to be nearly allied to _Tupaia_. +The genus _Parasorex_, from strata of similar age, has the dental formula +_i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃, and is regarded as connecting the +present with the following family. + + +_Family_ MACROSCELIDIDÆ. + +Skull with comparatively large brain-case, strong zygomatic arch, a +tympanic bulla, orbit surrounded by bone, imperforate jugal, and usually +no postorbital process. Molars broad, with four cusps arranged in a W. +Pubic symphysis long; proximal end of tibia and fibula united; radius +and ulna united or separate; metatarsus much longer than tarsus. A large +cæcum. Habits terrestrial, saltatorial, and nocturnal. The family is +confined to Africa. + +_Macroscelides._[534]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₂₋₃; +total 40 or 42. Distal extremity of radius and ulna united. Five digits +in manus, and five or four in pes. This genus, which is taken to include +_Petrodromus_, comprises ten species widely distributed throughout the +African continent. All are closely related, resembling one another +in general form, and even in the colour of the fur. They fall into +two groups, distinguished by the presence or absence of a small third +lower molar.[535] _M. tetradactylus_ (Fig. 284), the type of the genus +_Petrodromus_, differs from all the other species in the absence of the +hallux, and of the third lower molar. These animals are commonly known +as Jumping Shrews, and, like the following genus, have the muzzle much +produced. + +_Rhynchocyon._[536]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ²⁄₂; +total 36. Upper incisor frequently shed in the adult. Radius and ulna +distinct; hind limbs relatively shorter, and proboscis longer than in the +type genus; four digits in each foot. Four closely allied species have +been described from East Africa. The head and body of the type species +measures about 8 inches in length; and the long tail is covered with a +ringed skin, sparsely haired. Its habits are fossorial. + +[Illustration: FIG. 284.—_Macroscelides tetradactylus._ × ½. (From +Peters, _Reise nach Mossambique._)] + + +_Family_ ERINACEIDÆ. + +Skull with a small brain-case; no postorbital process; slender and +occasionally imperfect zygomatic arch, and an annular tympanic, which +does not form a bulla. Upper molars with four principal cusps and a small +central median cusp. Acromion of scapula bifid; pubic symphysis short; +radius and ulna free, but tibia and fibula united proximally. No cæcum; +penis carried forward and suspended from the wall of the abdomen. Habits +terrestrial. Found in the Palæarctic, Ethiopian, and Oriental regions. + +Subfamily =Gymnurinæ=.—Palate completely ossified; pelvis very narrow; +fur without spines. + +_Gymnura._[537]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃; total 44. +This genus, if _Hylomys_ is rightly included, is represented by the two +species, _G. rafflesi_ and _G. suilla_, from the Malay Peninsula and +Indian Archipelago. The former has the appearance of a large Rat with +a long tail and head and projecting mobile snout; the latter, which is +much smaller, with a short tail and small third upper premolar, has long +been known under the name of _Hylomys suillus_, and classed with the +_Tupaiidæ_. Both species present a very generalised type of dentition, +in this respect occupying an almost central position in the order. +_G. suilla_ is represented in Mount Kina-Balu, Borneo, by a variety +characterised by the presence of a dark dorsal streak. Many zoologists +prefer to retain _Hylomys_ as a distinct genus. + +Subfamily =Erinaceinæ=.—Palate imperfectly ossified; pelvis wide; fur +with spines. + +_Erinaceus._[538]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₁, _p_ ³⁄₂, _m_ ³⁄₃; total +36. The first pair of upper incisors (Fig. 285) are considerably larger +than the others, and are widely separated from one another in the middle +line; the canine is very similar to the third incisor; and, except +in _E. europæus_ (Fig. 285), each of these teeth is inserted by two +distinct roots (Fig. 280, p. 610). The first lower incisor is large and +proclivous. The number of vertebræ is C 7, D 15, L 6, S 3, C 11. + +[Illustration: FIG. 285.—Right lateral aspect of the anterior portion of +the skull of the Hedgehog (_Erinaceus europæus_). Enlarged. (From Dobson, +_Proc. Zool. Soc._ 1881, p. 403.)] + +The Hedgehogs comprise nearly twenty species, distributed throughout +Europe, Africa, and the greater part of Asia, but not found in +Madagascar, Ceylon, Burma, Siam, the Malay Peninsula, or Australia. All +the species resemble one another in the armature of spines investing the +upper surface and sides of the body; and all possess the power of rolling +themselves up into the form of a ball, protected on all sides by the +strong spines; the dorsal integument being brought downwards and inwards +over the head and tail, so as to include the limbs also, by the action of +special muscles. The common Hedgehog (_E. europæus_) is the most aberrant +species, differing from all the rest in the peculiarly shaped and +single-rooted third upper incisor and canine (Fig. 285), and in its very +coarse, harsh fur. The dentition of the long-eared North Indian form, +_E. collaris_ (Fig. 280), may be considered characteristic of all the +other species, the only important differences being found in the variable +size and position of the second upper premolar, which is very small, +external, and deciduous in the Indian _E. micropus_ and _pictus_. The +former species, limited to South India, is further distinguished by the +absence of the jugal bone. Of the African species, _E. diadematus_, with +long frontal spines, is probably the commonest; while _E. albiventris_ +has been made the type of a separate genus on account of the total +absence of the hallux. + +The well-known European species feeds on insects, worms, slugs, mice, +rats, lizards, snakes, etc., as well as on eggs, fruit, and roots. It +hibernates during the winter. The young are usually produced in July +or August in litters of not more than four, but there may be a second +litter in October; and the period of gestation is believed not to exceed +a month. The Indian, and probably also the African species, do not +hibernate. + +The existing _E. europæus_ dates from the Pleistocene period, and extinct +species of the genus are found in the Upper and Middle Miocene of the +Continent. + +_Extinct Genera._—The French Lower Miocene genus, _Palæoerinaceus_, +appears to be allied to _Erinaceus_, but is distinguished by the +wider and completely ossified palate. In the Upper Eocene of Central +France there are two genera, which appear to be most nearly allied to +_Gymnura_, although connected by _Palæoerinaceus_ with _Erinaceus_. Of +these _Necrogymnurus_,[539] with which _Cayluxotherium_ is apparently +identical, has teeth like _Gymnura_, but an imperfectly ossified palate +like _Erinaceus_; and the skull is remarkable for the peculiar rugose +structure of the parietal and temporal regions. _Comphotherium_ is +distinguished by the presence of a cingulum to the lower molars, like +that found in _Gymnura_. + + +_Family_ SORICIDÆ. + +Skull (Fig. 286) long and narrow, with no zygomatic arch or postorbital +process, and the tympanic ring-like and not forming a bulla. Upper molars +with the cusps arranged in a distinct W. No pubic symphysis. The tibia +and fibula united. No cæcum. Habits usually terrestrial, rarely aquatic. +Distribution extensive. + +The Shrews are Rat-like or Mouse-like insectivores, with the body covered +with hair, and the muzzle long and pointed. Their dentition (Fig. 286) +is peculiar and characteristic. Thus the first upper incisor is large +and hook-like, with a more or less developed basal cusp on the posterior +border. Between this and the last premolar there are a variable number +of small teeth, representing the other incisors, the canine, and the +anterior premolars; although, owing to the early obliteration of the +maxillo-premaxillary suture, their homology is exceedingly difficult to +determine. Three molars are invariably present, of which the third is +much the smallest. In the mandible there are always six teeth, but in one +species of _Myosorex_ there may be a seventh. The first lower incisor +is usually directed horizontally forwards; the second incisor (formerly +reckoned as the canine) is the smallest tooth of the series, the fourth +premolar being slightly larger. + +This family, which includes considerably more than half the +representatives of the order, has a distribution coextensive with the +latter. Many classifications of this difficult group have been attempted, +but according to the latest proposal of Dr. Dobson,[540] the genera may +be divided into two subfamilies, distinguished by the apparently trivial +character of the colour of the teeth. + +[Illustration: FIG. 286.—Left lateral view of the cranium and mandible +of _Sorex veræpacis_. In the cranium—_i_, first incisor; _c_, fourth +incisor; _p_, canine; _m_, fourth premolar: in the mandible—_i_, first +incisor; _c_, second incisor; _p_, fourth premolar; _m_, first molar. +(From Alston, _Proc. Zool. Soc._ 1877.)] + +Subfamily =Soricinæ=.—Summits of the teeth coloured red. + +_Sorex._[541]—Dentition: _i_ ⁴⁄₂, _c_ ¹⁄₀, _p_ ²⁄₁, _m_ ³⁄₃; total 32. +Openings of male and female generative organs separated from the anal +orifice; penis cylindrical or tapering; ear well developed; tail long, +covered with equal or subequal hairs. + +It has been shown by Brandt that the position of the premaxillo-maxillary +sutures in the type of the genus is between the fourth and fifth tooth, +so that it appears that we must regard this genus as differing from all +other Eutherian mammals in having four upper incisors. Dr. Dobson, in +his paper quoted, classes the tooth here reckoned as the upper canine +with the premolar series in all the Shrews. Habits terrestrial. Species +numerous, inhabiting the Palæarctic and Nearctic regions. + +Of the two species found in the British Isles the Common Shrew (_S. +vulgaris_, Fig. 287) is by far the most common in England, and is about +the size of the House Mouse, to which it approximates in general form. +The body is clothed with close long fur, very soft and dense, and varying +in colour from light reddish to dark brown above, rarely speckled or +banded with white. The under surface of both the body and the tail is +grayish. The basal four-fifths of all the hairs above and beneath are +dark bluish-gray; the hairs of the tail are less densely set and coarser. +On each side of the body, at a point about one-third of the distance +between the elbow and the knee, may be found, especially in the rutting +season, a gland covered by two rows of coarse hairs. This secretes a +peculiar fluid, on which the odour of the animal depends; this odour +being evidently protective, and rendering the creature secure against the +attacks of many predaceous animals. + +The geographical range of the Common Shrew is exceedingly wide, extending +eastwards through Europe and Asia (north of the Himalayas) to North +America. + +[Illustration: FIG. 287.—The Common Shrew (_Sorex vulgaris_).] + +The Lesser Shrew (_S. pygmæus_[542]) is far less common in England and +Scotland, although more abundant in Ireland, where _S. vulgaris_ is +unknown. It is distinguished from the latter not only by its inferior +dimensions, but also by the circumstance that the third upper incisor is +not longer than the fourth, and by the considerably shorter length of the +forearm and manus. This species extends through Europe and Asia as far +as the inland of Saghalin. Both this and the preceding species generally +live in wooded districts, making their nests under the roots of trees, or +in slight hollows. The great mortality noticeable among the Shrews in the +early part of the autumn is probably due to insufficiency of food. The +breeding season extends from the latter part of April to the beginning of +August. The young, which are blind, naked, and toothless at birth, are +very quickly developed. The number in a litter is usually from five to +seven, but may be as many as ten. + +The Alpine Shrew (_S. alpinus_), which is restricted to the Alpine region +of Central Europe, is slightly larger than the common species, from which +it is distinguished by the longer tail, the length of which exceeds that +of the head and body, by the fur being dark on both surfaces of the body, +and also by the larger size of the upper canine. + +In North America _S. bendirei_ is by far the largest species of the +genus; and, as in many other species of the same country, the fourth +upper incisor is relatively small. In _S. hoyi_ (separated by some +writers as _Microsorex_), of the same country, this tooth is rudimentary. + +Other North American Shrews, which are regarded by some zoologists as +generically distinct under the name of _Neosorex_, are aquatic, and +thus take the place of the Old World genus _Crossopus_. These are _S. +palustris_ of the Rocky Mountains and _S. hydrodromus_ of Unalaska +Island, both of which resemble _Crossopus_ in having the feet provided +with swimming fringes, but agree with the other species of _Sorex_ in +their dentition and the character of the tail. The former species is +about the size of _Crossopus fodiens_, while the latter is scarcely +larger than _S. pygmæus_. + +_Soriculus._[543]—Dentition: _i_ ⁴⁄₂, _c_ ¹⁄₀, _p_ ¹⁻²⁄₁, _m_ ³⁄₃; total +30, or rarely 32. Opening of male or female generative organs forming +with the anal orifice a shallow cloaca. Ear and tail as in _Sorex_. First +upper incisor with an internal cusp. Habits terrestrial. + +This genus is the only representative in the Oriental region of the +_Soricinæ_, which are otherwise confined to the Palæarctic and Nearctic +regions. The Indian and Burmese species comprise _S. nigrescens_, _S. +caudatus_, and _S. macrurus_. + +_Notiosorex._[544]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ¹⁄₁, _m_ ³⁄₃; total +28. Tail moderate; first upper incisor without an inner cusp; other +characters as in _Soriculus_. Habits terrestrial. + +This American genus is represented by _S. crawfordi_ and _S. evotis_, +which are found in Central America and Mexico, and are thus some of the +most southerly representatives of the Shrews in that continent. Their +external appearance is very similar to that of the Old World genus +_Crocidura_. + +_Blarina._[545]—Dentition: _i_ ⁴⁻³⁄₂, _c_ ¹⁄₀, _p_ ²⁄₁, _m_ ³⁄₃; total +32 or 30. Ear truncated above; tail short; otherwise as in _Soriculus_. +This group of so-called Earless or Short-tailed Shrews is mainly North +American, the common forms being _B. dekayi_ and _B. brevicauda_. The +species vary considerably in size; and _B. mexicana_ and _micrura_ extend +the range of the genus into Mexico and Guatemala. The following account +of the habits of _B. brevicauda_ is taken from Dr. Merriam’s _Mammals +of the Adirondack Region_: “The rigours of our northern winters seem to +have no effect in diminishing its activity, for it scampers about on the +snow during the severest weather, and I have known it to be out when the +thermometer indicated a temperature of -20° Fahr. It makes long journeys +over the snow, burrowing down whenever it comes to an elevation that +denotes the presence of a log or stump, and I am inclined to believe that +at this season it must feed largely upon the chrysalides and larvæ of +insects that are always to be found in such places.” Dr. Merriam has made +the interesting discovery that the common short-tailed North American +Shrew supplements its insectivorous fare by feeding on beech-nuts, which +will account for the generally very worn state of the teeth in this +species. + +_Crossopus._[546]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ²⁄₁, _m_ ³⁄₃; total +30. Opening of male or female generative organs enclosed within the same +ring as the anal orifice; penis broad, with lateral processes. Ears +small, not truncated. Tail long, with an inferior fringe of elongated +hair; feet also fringed. Habits aquatic. The Palæarctic Water-Shrew (_C. +fodiens_) is considerably larger than the Common Shrew, from which it is +readily distinguished externally by its shorter and much broader muzzle, +comparatively smaller eyes, and larger feet adapted for swimming,—the +sides of the feet and toes being provided with comb-like fringes of stiff +hairs. The tail is longer than the body, and possesses a well-developed +swimming fringe of moderately long, regularly arranged hairs, which +extend along the middle of the flat under surface from the end of its +basal third to its extremity. The fur of the body is long and very dense, +varying much in colour in different individuals, and this has given rise +to descriptions of many nominal species; the prevailing shades are dark +brown, almost black, above, and more or less bright ashy tinged with +yellowish beneath; sometimes in the same litter there are individuals +with the under surface more or less dark coloured. In the number as well +as in the shape of the teeth the Water-Shrew differs from the Common +Shrew: there is a premolar less on each side above; the bases of the +teeth are much more prolonged posteriorly; and their cusps are much less +stained brown, so that in old individuals with worn teeth they often +appear altogether white. This species resembles the otter in its aquatic +habits, swimming and diving with great agility. It frequents rivers and +lakes, making its burrows in the overhanging banks, from which when +disturbed it escapes into the water. Its food consists of insects and +their larvæ, small crustaceans, and probably the fry of small fishes. It +is generally distributed throughout England, is less common in Scotland, +and as yet it has not been recorded in Ireland; specimens have been +obtained from many parts of Europe, and also from Asia as far eastward as +the Altai Mountains. + +Subfamily =Crocidurinæ=.—Teeth completely white. + +_Myosorex._[547]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ²⁄₁₋₂, _m_ ³⁄₃; total +30 or 32. Penis cylindroid and tapering; male or female generative +organs opening close to anal orifice, but not forming a cloaca. Ears +well developed; tail long, clothed with equal or subequal hairs. Habits +terrestrial. + +This genus is typically represented by _M. varius_, a very small Shrew +from the Cape, which is quite unique among the whole family in having a +rudimental seventh pair of lower teeth. + +_Crocidura._[548]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ²⁻¹⁄₁, _m_ ³⁄₃; total +28 or 30. Male or female generative organs forming a short cloaca with +the anal orifice. Tail long, with a mixture of long and short hairs. +Other characters as in _Myosorex_. Habits terrestrial. + +This Old World genus includes over seventy nominal species, which have +been divided into four subgenera, _C. aranea_ and _C. suaveolens_ of +Continental Europe, and _C. cœrulea_ of India, being well-known forms. +The species are very variable and difficult to discriminate. _C. aranea_ +has a very wide distribution, ranging from Central and Southern Europe +to North Africa and Central Asia. The name Musk-Rat is popularly applied +in India to _C. cœrulea_, which frequents houses at night, hunting round +rooms for cockroaches and other insects, and occasionally uttering a +sharp shrill cry. The strong musky odour of this animal arises from +large glands situated beneath the skin of the side of the body, a short +distance behind the fore limbs. This odour is so powerful and penetrating +that it is popularly believed in India that if the animal runs over a +corked bottle of wine or beer it will infect the fluid within. Jerdon +says that certainly many bottles are met with quite undrinkable from the +peculiar musky odour of their contents, but, rejecting the possibility of +its passing through the glass, he attributes it to the corks having been +infected previously to bottling, stating in corroboration of this view +that he has never found the odour in liquors bottled in England. + +_Diplomesodon._[549]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₀, _p_ ¹⁄₁, _m_ ³⁄₃; +total 26. Tail moderate; soles of the feet hairy. Other characters as in +_Crocidura_. Habits terrestrial. + +This genus is represented only by _D. pulchellus_ of the Kirghiz steppes, +which is allied to the following form, although retaining the normal +Shrew-like external contour. + +_Anurosorex._[550]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₀, _p_ ¹⁄₁, _m_ ³⁄₃; total +26. Ear very short; tail rudimental or short; soles of feet naked. Other +characters as in _Diplomesodon_. + +The two species of this genus are Mole-like terrestrial forms, of which +the typical _A. squamipes_ occurs in Tibet, while _A. assamensis_ is +found in Assam. The latter species has the longer tail. The habits of +both are probably fossorial. + +_Chimarrogale._[551]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ¹⁄₁, _m_ ³⁄₃; +total 28. Penis broad, with lateral processes; male or female generative +organs opening within the same integumentary ring as the anal orifice. +Tail long, with an inferior fringe of elongated hairs; ears small; +plantar callosities simple; toes free. Habits aquatic. + +This genus includes _C. himalayica_ of the Himalaya and _C. +platycephalus_ of Japan. Both have the feet fringed, and, together with +the next genus, may be regarded as the eastern analogues of _Crossopus_ +among the red-toothed series; their structural resemblances to the +latter, if Dr. Dobson’s classification is a natural one, being probably +due to adaptation for a similar mode of life. + +_Nectogale._[552]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ¹⁄₁, _m_ ³⁄₃; +total 28. External ears not forming a conch, valvular. Plantar +callosities forming adhesive pads; toes webbed. Other characters as in +_Chimarrogale_. Habits aquatic. + +[Illustration: FIG. 288.—_Nectogale elegans._ (From Milne-Edwards, +_Mammif. Tibet_.)] + +The sole representative of this genus is the Tibetan Water-Shrew (_N. +elegans_, Fig. 288), which differs from all other members of the family +by the webbed toes and the presence of the disc-like adhesive pads on the +under surface of the feet, which are believed to enable the creature to +hold on to smooth rocks or stones in the beds of the streams it inhabits. +This species is probably more completely aquatic in its habits than the +allied _Chimarrogale_. + +_Fossil Soricidæ._—Remains of existing species of _Sorex_ or _Crossopus_ +occur in the Norfolk Forest bed, while an extinct species has been found +in the Pleistocene of Sardinia. _Crocidura_ occurs in the cavern-deposits +of Madras. Shrews from the Miocene and Upper Eocene of Europe have been +referred to _Sorex_ and the genus _Amphisorex_, which is a synonym of +_Crossopus_. + + +_Family_ TALPIDÆ. + +Allied to the _Soricidæ_, but distinguished by the presence of a +zygomatic arch and auditory bulla in the skull, and by the form of +the teeth. The eyes are very small, and in some species covered with +skin; the ears are short and concealed by the fur; the fore limbs are +generally more or less modified for digging; there is no symphysis pubis; +the intestine has no cæcum; the tibia and fibula are united; and the +unicuspidate first upper and lower incisors are not extended horizontally +forwards. + +This family is connected with the _Soricidæ_ by _Urotrichus_ and +_Uropsilus_. All the members are limited to the temperate regions +of Europe, Asia, and North America; and the majority of them are of +fossorial habits, although a few are aquatic or cursorial. The family has +been divided into two subfamilies by Professor Mivart, and since this +arrangement has been very generally adopted it will be followed here. +From the presence of intermediate forms like _Scaptonyx_ Dr. Dobson, in +the second part of his _Monograph of the Insectivora_, has proposed a +different arrangement, which, with the omission of some forms which are +of not more than subgeneric value, is as follows:— + + MYOGALÆ—_Myogale_. + CONDYLURÆ—_Condylura_. + SCALOPES { _Scapanus_. + { _Scalops_. + TALPÆ—_Talpa_. + UROTRICHI { _Scaptonyx_. + { _Urotrichus_. + UROPSILI—_Uropsilus_. + +Subfamily =Myogalinæ=.—Clavicles and humerus moderately elongated; manus +without falciform bone. + +_Myogale_.[553]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃; total +44. Feet webbed. Habits aquatic. This genus is represented by the two +species _M. moschata_ (Fig. 289) and _M. pyrenaica_, of which the former +is by far the largest member of the family, its total length being about +16 inches. Its long proboscis-like snout projects far beyond the margin +of the upper lip; the toes are webbed as far as the bases of the claws; +and the long scaly tail is laterally flattened, so as to form a powerful +instrument of propulsion when swimming. This species inhabits the banks +of streams and lakes in South-East Russia, where its food consists of +various aquatic insects. _M. pyrenaica_, living in a similar manner in +the region of the Pyrenees, is very much smaller, has a round tail, and +a proportionally longer snout. Fossil remains of _M. moschata_ occur in +the Norfolk Forest bed, and were originally described under the name of +_Palæospalax_. The genus is also represented in the Middle and Lower +Miocene of the Continent. + +[Illustration: FIG. 289.—The Desman (_Myogale moschata_). ¹⁄₃ natural +size.] + +_Urotrichus._[554]—Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ⁴⁄₃ or ³⁄₄, _m_ +³⁄₃; total 36. Feet not webbed; manus broad. Habits fossorial. The +Mole-Shrews, as these animals are called, are represented by _U. +talpoides_ of the mountains of Japan and _U. gibbsi_ of North America. +These two species are small and closely allied animals; the American form +(which it has been proposed to separate subgenerically as _Neurotrichus_) +having _p_ ³⁄₄. + +_Uropsilus._[555]—Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total +34. Manus narrow; tail naked and scaly. Habits cursorial. The single +species, _U. soricipes_, from the borders of Tibet, is a slate-coloured +animal with the external form of a Shrew but the skull of a Mole. + +Subfamily =Talpinæ=.—Clavicle and humerus very short and broad; manus +with a large falciform bone. + +A. First upper incisor much larger than the second (New World Moles). + +_Scalops._[556]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₀, _p_ ³⁄₃, _m_ ³⁄₃; total +36. Extremity of muzzle simple; hind feet webbed; tail short and nearly +naked. Represented by three species in the United States. + +_Scapanus._[557]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃; total +44. Extremity of muzzle simple. The two North American species of this +genus resemble _Scalops_ in general characters, but have a dentition like +_Condylura_. The habits are like those of the latter, and the right to +generic distinction is doubtful. + +_Condylura._[558]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃; +total 44. Extremity of muzzle surrounded by filiform appendages. The +Star-nosed Mole (_C. cristata_) derives its name from the star-like ring +of appendages at the extremity of the muzzle, with the nostrils in the +centre. The general contour is Mole-like, but the tail is nearly as long +as the body, and the manus is somewhat less powerful, with its terminal +phalanges not cleft. The length of the head and body is about 5 inches. +This species is common in parts of North America, and forms tunnels in +the ground like the Common Mole. + +B. First upper incisor scarcely larger than the second (Old World Moles). + +_Scaptonyx._[559]—Dentition: _i_ ³⁄₂, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃; total +42. Manus moderately broad, as in _Urotrichus_. Represented only by _S. +fusicaudatus_ of Eastern Tibet, which may be regarded as connecting +_Talpa_ with _Urotrichus_, having the head of the former and the limbs of +the latter. + +_Talpa._[560]—Dentition (usually): _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃; +total 44. Manus extremely broad. + +This genus includes the true Moles, of which the common English +Mole[561] (_T. europæa_) is the type. This animal is about 6 inches in +total length, of which rather more than one inch is occupied by the +tail. The body is elongated and cylindrical, and, owing to the very +anterior position of the fore limbs, the head appears to rest between +the shoulders; the muzzle is long and obtusely pointed, terminated by +the nostrils, which are close together; the minute eye is almost hidden +by the fur; the ear is without a conch, and opens on a level with the +surrounding integument. The fore limbs are rather short and very +muscular, terminating in broad, naked, shovel-shaped feet, with the palms +normally directed outwards, and each with five subequal digits armed with +strong flattened claws. The hind feet are long and narrow, and the toes +are provided with slender claws. The body is densely covered with soft, +erect, velvety fur, the hairs being uniform in length and thickness, +except on the muzzle and short tail. The colour of the fur is generally +black, with a more or less grayish tinge, or brownish-black, but various +paler shades up to pure white have been observed. + +The food of the Mole consists chiefly of the earth-worm, in pursuit of +which it forms its well-known underground excavations. Its habits were +many years ago studied and described by M. Henri le Court. Like many +other mammals, the Mole has a lair to which it may retire for security. +This consists of a central nest formed under a hillock, placed in some +protected situation, as under a bank, or between the roots of trees. The +nest, which is lined with dried grass or leaves, communicates with the +main run by four passages, of which only one joins it directly, leading +downwards for a short distance and then ascending again. The other +three are directed upwards and communicate at regular intervals with a +circular gallery constructed in the upper part of the hillock, which in +turn communicates by five passages leading downwards and outwards with +another much larger gallery placed lower down on a level with the central +nest, from which passages proceed outwards in different directions, one +only communicating directly with the main run, while the others, curving +round, either soon join or end blindly. The main run is somewhat wider +than the animal’s body: its walls are smooth, and formed of closely +compressed earth, the depth varying according to the nature of the soil, +but ordinarily from 4 to 6 inches. Along this tunnel the animal passes +backwards and forwards several times daily, and here traps are laid by +mole-catchers for its capture. From the main run numerous passages are +formed on each side, along which the animal hunts its prey, throwing out +the soil in the form of mole-hills. The Mole is one of the most voracious +of mammals, and, if deprived of food, is said to die in from ten to +twelve hours. Almost any kind of flesh is eagerly devoured by captive +Moles, which have been seen by various observers, as if maddened by +hunger, to attack animals nearly as large as themselves, such as birds, +lizards, frogs, and even snakes; toads, however, they will not touch, and +no form of vegetable food attracts their notice. If two Moles be confined +together without food, the weaker is invariably devoured by the stronger. +Moles take readily to the water, in which respect they resemble their +representatives on the North American continent. Bruce, writing in 1793, +remarks that he saw a Mole paddling towards a small island in the Loch of +Clunie, 180 yards from land, on which he noticed mole-hills. + +The sexes come together about the second week in March, and the +young—generally from four to six in number—which are brought forth in +about six weeks, quickly attain their full size. + +[Illustration: FIG. 290.—Skeleton of Mole × ⅔ (lower jaw removed to +show base of skull). _c_, Calcaneum; _c.h._, clavicular articulation +of the humerus; _cl._, clavicle; _e.c_, external condyle of humerus; +_f._, femur; _fb_, fibula; _fc_, falciform bone (radial sesamoid); _h_, +humerus; _i.c_, internal condyle of humerus; _il_, left ilium; _i.p_, +ramus of the ilium and pubis; _is._, ischium; _l.d_, ridge of insertion +of latissimus dorsi muscle; _l.t_, lesser trochanter; _m_, manubrium +sterni; _o_, fourth intercentral ossicle; _ol_, olecranon; _p._, pubis +widely separated from that of the opposite side; _pa._, patella; _p.m._, +ridge for insertion of pectoralis major muscle; _pt._, pectineal +eminence; _r_, radius; _rb_, first rib; _s_, plantar sesamoid ossicle +corresponding to the radial sesamoid (os falciforme) in the manus; _sc._, +scapula; _s.h._, scapular articulation of the humerus; _t_, tibia; _u_, +ulna.] + +The Mole exhibits in the whole of its organisation a perfect adaptation +to its peculiar mode of life. In the structure of the skeleton (Fig. +290) very striking departures from the typical mammalian form are +noticeable. Thus the presternum is so much produced anteriorly as to +extend forward as far as a vertical line from the second cervical +vertebra, carrying with it the very short and almost quadrate clavicle, +which is articulated with its anterior extremity and distally with the +humerus; being also connected ligamentously with the scapula. The fore +limbs are thus brought opposite the sides of the neck, and from this +position a threefold advantage is derived: in the first place, as this +is the narrowest part of the body, they add but little to the general +width, which if increased, would lessen the power of movement in a +confined space; secondly, this position allows of a longer fore limb than +would otherwise be possible, and so increases its power; and, thirdly, +although the entire limb is relatively very short, its anterior position +enables the animal, when burrowing, to thrust the claws so far forward +as to be in a line with the end of the muzzle, the importance of which +is evident. Posteriorly, the hind limbs are similarly removed out of the +way by approximation of the hip-joints to the centre line of the body. +This is effected by inward curvature of the innominate bones at the +acetabula to such an extent that they almost meet in the centre, while +the pubic bones are widely separated behind. The shortness of the fore +limb is caused by the great reduction in the length of the humerus, which +has lost all resemblance to its normal shape. In addition to the usual +articulation with the glenoid cavity of the scapula, the humerus also has +a separate articulation with the extremity of the clavicle. The bones +of the manus are enormously expanded laterally; this expansion being +increased by the large sickle-like bone on the radial side of the carpus, +which is considered by some anatomists to represent the prepollex. The +skull is long and tapering, with very slender zygomatic arches and +elongated nasals, which are ankylosed together, and in advance of which +the mesethmoid is more or less ossified. The vertebræ are usually C 7, +D 13, L 6, S 6, C 10-12; all having very strong surfaces for mutual +articulation. The upper incisors are chisel-like, and the canine has two +roots; the first three upper premolars are simple and conical, but the +fourth is much larger, and canine-like. In the mandible the incisors are +small and somewhat proclivous, while the canine can only be distinguished +from them by its position: the first lower premolar is larger than the +others. + +The Common Mole has an exceedingly wide distribution, ranging over the +greater part of the Palæarctic region, where it is met with in places so +widely sundered as England and Japan. It occurs in both the Himalaya and +Altai mountains. In Ireland it is unknown, and in Scotland it extends as +far north as Caithness. Eight species of the genus are recognised, which +may be grouped, from the characters of their dentition, as follows, viz.: +_i_ ³⁄₃, _c_ ¹⁄₀, _p_ ⁴⁄₄, _m_ ³⁄₃, _T. wogura_; _i_ ³⁄₃, _c_ ¹⁄₁, _p_ +⁴⁄₄, _m_ ³⁄₃, _T. europæa_, _cæca_, _longirostris_, _micrura_; _i_ ³⁄₃, +_c_ ¹⁄₁, _p_ ³⁄₄, _m_ ³⁄₃, _T. leucura_, _leptura_; _i_ ³⁄₃, _c_ ¹⁄₁, _p_ +³⁄₃, _m_ ³⁄₃, _T. moschata_. + +Except in _T. europæa_, the eyes are covered by a membrane. In _T. +micrura_ the short tail is concealed by the fur. _T. cæca_ is found south +of the Alps; the remaining species are Asiatic, and two only—_T. micrura_ +and _T. leucura_—occur south of the Himalaya. _T. moschata_, of Tibet, +is regarded by some zoologists as generically distinct under the name of +_Scaptochirus_. + +Remains of _T. europæa_ occur in the Norfolk Forest bed, while extinct +species are found in the European Tertiaries as far down as the Lower +Miocene, although it has been proposed to separate some of these forms +generically. _Protalpa_, of the Upper Eocene Phosphorites of Central +France, is very closely allied, but the structure of the humerus is +somewhat less specialised. + +_Extinct Genera._—A number of extinct Insectivora from the European +Tertiaries more or less closely allied to the Moles have been described, +but since our knowledge of most of them is extremely imperfect their +precise affinities are in many instances problematical. Of these, the +Lower Miocene _Tetracus_ is said to have affinity both with _Myogale_ and +_Erinaceus_; while the forms described as _Mysarachne_ and _Echinogale_, +are considered to connect the present with the two preceding families. +_Plesiosorex_ is another Lower Miocene type known only by the mandible, +in which there are ten teeth; it is generally referred to the +_Myogalinæ_. The minute _Amphidozotherium_, of the French Phosphorites, +is considered to be allied to _Urotrichus_. + + +_Family_ ADAPISORICIDÆ. + +This extinct family is represented by the genera _Adapisorex_ and +_Adapisoriculus_, of the lowest Eocene of Rheims, which are regarded as +allied to the _Soricidæ_, but somewhat more specialised. In the type +genus the formula of the lower teeth is _i_ 2, _c_ 1, _p_ 4, _m_ 3; the +incisors and canine being proclivous, and the molars (of which the last +is small and without a third lobe) quadritubercular. _Adapisoriculus_ is +a smaller form with differently shaped molars. + +[Illustration: FIG. 291.—The last left upper cheek-teeth of +_Pleuraspidotherium aumonieri_; from the Lowest Eocene of Rheims. _pr_, +protocone; _me_, metacone; _pa_, paracone; _b_, cingulum-cusp. (From +Osborn.)] + +Here also may be mentioned the genera _Orthaspidotherium_ and +_Pleuraspidotherium_, from the above-mentioned deposits, which are +probably members of the present order. They appear to have been animals +somewhat smaller than a Hedgehog, with quadritubercular upper molars +(Fig. 291), and the hinder premolars more complex than those of the +_Erinaceidæ_. In the first-named genus the dental formula is _i_ ³⁄₃, _c_ +¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃; the third and fourth upper premolars having one +outer column. _Pleuraspidotherium_ has apparently only three premolars, +of which the third and fourth (Fig. 291) have two outer columns. The +humerus in both has no entepicondylar foramen, the femur has a third +trochanter, and the astragalus is vertically perforated. + + +_Family_ POTAMOGALIDÆ. + +Skull with a small brain-case, no zygomatic arch or postorbital process, +and the tympanic annulate and not forming a bulla. Upper molars with the +cusps arranged in a broad V, and somewhat intermediate in structure +between those of the preceding and succeeding families. No clavicle; +pubic symphysis ligamentous; tibia and fibula typically united distally. +No cæcum. Confined to the Ethiopian region. + +[Illustration: FIG. 292.—_Potamogale velox._ × ¼. (From Allman, _Trans. +Zool. Soc._ vol. vi. pl. i.)] + +_Potamogale._[562]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total +40. Represented only by _P. velox_ of Western Equatorial Africa. This +animal (Fig. 292) inhabits the banks of streams, and is thoroughly +adapted for an aquatic life; it is nearly 2 feet in length, the +tail measuring about half. The long cylindrical body is continued +uninterruptedly into the thick laterally compressed tail, the legs are +very short, and the toes are not webbed, progression through the water +evidently depending wholly on the action of the powerful tail, while the +limbs are folded inwards and backwards. The muzzle is broad and flat, and +the nostrils are protected by valves. The fur is dark brown above, the +extremities of the hairs on the back being of a metallic violet hue by +reflected light, beneath whitish. This curious animal was discovered by +M. du Chaillu. + +_Geogale._[563]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₂, _m_ ³⁄₃; total 34. +This genus is known solely by _G. aurita_, a small Mouse-like species +from Madagascar, agreeing closely with _Potamogale_ in the general form +of the skull and teeth. The tibia and fibula are distinct, but it is not +known whether a clavicle exists; and the material at present available is +insufficient to definitely fix the natural position of the genus. + + +_Family_ SOLENODONTIDÆ. + +Skull with a small brain-case constricted between the orbits, no +zygomatic arch or postorbital process, and the tympanic annulated and not +forming a bulla. Upper molars tritubercular, the cusps being arranged in +a V. Pubic symphysis short; tibia and fibula distinct. Vertebræ: C 7, D +15, L 4, S 5, C 23. No cæcum. The penis is carried forwards and suspended +from the abdomen; the testes are received into perineal pouches; the +mammary glands are post-inguinal; the uterine cornua end in cæcal sacs. + +[Illustration: FIG. 293.—_Solenodon cubanus._ × ⅕ (From Peters, _Abh. +Akad. Berlin_.)] + +_Solenodon._[564]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total +40. This genus, with _S. paradoxus_ and _S. cubanus_ (Fig. 293), from +Hayti and Cuba respectively, alone represents the family. These species, +which differ chiefly in the colour and quality of the fur, have a +remarkably long cylindrical snout, a long naked tail, feet formed for +running, and the body clothed with long, coarse fur. + +The position of the mammæ quite behind on the buttocks is unique among +Insectivora. The first upper incisor is much enlarged, and this and +the other incisors, canines, and premolars, closely resemble those of +_Myogale_; the second lower incisor is, as in _Potamogale_, much larger +than the anterior one, and is deeply hollowed out internally. While thus +apparently showing relationship with the _Talpidæ_, the form of the +crowns of the molar teeth connects them with the next family. + + +_Family_ CENTETIDÆ. + +Skull (Fig. 294) with a small cylindrical brain-case not constricted +between the orbits, no zygomatic arch or postorbital process, and the +tympanic annulate and not forming a bulla. Upper molars tritubercular. +Pubic symphysis short; and the tibia and fibula either united or free. +No cæcum. The penis is pendent and retractile within the fold of the +integument surrounding the anus; the testes are abdominal; the mammæ +are thoracic and ventral; and the uterine cornua are terminated by the +Fallopian tubes. All the species are limited to Madagascar. + +[Illustration: FIG. 294.—Left lateral view of the skull of the Tenrec +(_Centetes ecaudatus_). Reduced.] + +Subfamily =Centetinæ=.—Tibia and fibula distinct; testes near kidneys; +fur with spines. + +_Centetes._[565]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total 38. +Vertebræ: C 7, D 19, L 5, S 3, C 8. The single species is the well-known +Tenrec (_C. ecaudatus_), characterised by the absence of a tail; it +reaches a total length of from 12 to 16 inches, and is the largest known +Insectivore. The adult males have long canines, the extremities of the +lower pair being received into pits in front of the upper ones (Fig. +294). It is probably the most prolific of all mammals, since as many as +twenty-one young are said to have been brought forth at a birth. The +young have strong white spines arranged in longitudinal lines along the +back, but these are lost in the adult animal, which is provided only with +a nuchal crest of long rigid hairs. In rare instances a fourth upper +molar may be developed. + +_Hemicentetes._[566]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total +40. This genus is represented by the two species _H. semispinosus_ (of +which the skull is shown in Fig. 295) and _H. nigriceps_. It differs from +_Centetes_ by the presence of the third upper incisor, the much smaller +canines, and by the form of the skull. Both species are very much +smaller than _C. ecaudatus_, and the dorsal spines are retained in the +adult state. Vertebræ: C 7, D 16, L 5, S 3, C 9. + +_Ericulus._[567]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total 36. +Vertebræ: C 7, D 17, L 6, S 4, C 9. The single species, _E. setosus_, +is a Hedgehog-like animal, having the whole upper surface and the short +tail densely covered with close-set spines. The facial bones are much +shorter than in any of the preceding genera, and the first upper incisor +is elongated, as in _Erinaceus_. Judging from the slight development of +the cutaneous muscles compared with those of the true Hedgehogs, it is +probable that complete involution of the body does not take place. + +Subfamily =Oryzorictinæ=.—Tibia and fibula united; testes near urethra; +fur without spines. + +[Illustration: FIG. 295.—Skull of _Hemicentetes semispinosus_. × 2. (From +Mivart, _Proc. Zool. Soc._ 1871.)] + +_Microgale._[568]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total +40. This genus includes _M. longicaudata_ and _M. cowani_, both of which +are small Mouse-like species, the former with a tail double the length +of the head and body, and having 43 caudal vertebræ; teeth like those +of _Centetes ecaudatus_, but, owing to the comparatively much shorter +muzzle, not separated by wide spaces, and the last premolar and molar +with internal basal processes. + +_Oryzorictes._[569]—Represented by two species, _O. hova_ and _O. +tetradactylus_, the latter distinguished by the presence of only four +digits in the manus, the three inner having long laterally compressed +fossorial claws. The general form of the head and body of the two species +known is like that of a Mole. These animals burrow in the rice-fields and +do much damage to the crops. + + +_Family_ CHRYSOCHLORIDÆ. + +Skull conical, not constricted between the orbits, without postorbital +process, but with well-developed zygomatic arch and tympanic bulla. Upper +molars tritubercular, with the crowns very tall. No pubic symphysis; the +tibia and fibula united. The eyes are covered by the hairy integument; +the ears short and concealed by the fur; the internal generative organs +are as in _Centetinæ_; the mammæ are thoracic and inguinal and placed in +cup-shaped depressions. Habits fossorial. Confined to the southern part +of the Ethiopian region, not extending to Madagascar. + +This family is closely allied to the _Centetidæ_, occupying the same +relative position with respect to that family that the _Talpidæ_ does +to the _Soricidæ_. Compared with the _Talpidæ_, we find the following +differences in the structural adaptation to a fossorial life; the +manubrium sterni is not anteriorly elongated, neither are the clavicles +shortened; but this is compensated for by a deep hollowing out of the +antero-lateral walls of the thorax, the ribs in these parts and the +sternum being convex inwards. The long clavicles have their distal +extremities pushed forward, and the concavities on the sides and inferior +surface of the thorax lodge the thick muscular arms. + +[Illustration: FIG. 296.—The Golden Mole (_Chrysochloris obtusirostris_).] + +_Chrysochloris._[570]—Dentition: _i_ ³⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁻²⁄₃₋₂; +total 40 or 36. Vertebræ: C 7, D 19, L 3, S 5, C 8. This genus includes +some seven or eight South African species, commonly known as Golden +Moles (Fig. 296). Those species, in which the molars are reduced to ²⁄₂, +with a basal talon to the lower ones, and without a prominence in the +temporal fossa, have been placed in a separate genus, _Chalcochloris_, +by Professor Mivart. Nearly all the species have the fur of the upper +surface of a brilliant metallic lustre, varying from golden bronze to +green and violet of different shades. The manus has four digits, of which +the two outer are small, while the middle ones are large, with immensely +powerful claws. + +_Extinct Types._—The only fossil forms which can be referred to +the section of the Insectivora with tritubercular molars are the +_Leptictidæ_, of the Eocene and Miocene of North America. This family +includes the genera _Leptictis_, _Mesodectes_, and _Ictops_, all of which +are regarded by Dr. Schlosser as true Insectivora, although they were +placed by Professor Cope with the Creodont Carnivora. + + _Bibliography of Insectivora._—Peters, _Reise nach + Mossambique—Säugeth._ 1852; Id. “Ueber die Classification + der Insectivora,” _Monatsb. Akad. Wissensch. Berlin_, 1865, + and other papers; Mivart, “On the Osteology of Insectivora,” + _Journ. Anat. and Phys._ 1867, 1868, and _Proc. Zool. Soc._ + 1871; Gill, “Synopsis of Insectivorous Mammals,” _Bull. Geol. + and Geog. Survey, U.S.A._ Washington, 1875 (includes a + general bibliography of the order); Dobson, _Monograph of the + Insectivora, Systematic and Anatomical_, London, 1882-90. + + + + +CHAPTER XIII + +THE ORDER CHIROPTERA. + + +Mammals, having their fore limbs specially modified for flight. The +forearm consists of a rudimentary ulna, and a long curved radius. +The carpus has six bones supporting a small pollex and four greatly +elongated fingers, between which and the sides of the body and the +hinder extremities a thin expansion of the integument (the wing-membrane +or patagium) is extended. The knee is directed backwards, owing to the +rotation of the hind limb outwards by the wing membrane; a peculiar +elongated cartilaginous process (the calcar), rarely rudimentary or +absent, arising from the inner side of the ankle-joint, is directed +inwards, and supports part of the posterior margin of an accessory +membrane of flight, extending from the tail or posterior extremity of +the body to the hinder limbs (the interfemoral membrane). The penis +is pendent; the testes are abdominal or inguinal; the mammary glands +thoracic and generally postaxillary; the uterus is simple or with more or +less long cornua; the placenta discoidal and deciduate; and the smooth +cerebral hemispheres do not extend backwards over the cerebellum. The +dental series includes incisors, canines, premolars, and molars and never +exceeds _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total 38. + +The animals comprised in this order are at once distinguished by the +presence of true wings, and this peculiarity is accompanied by other +modifications of bodily structure having special relation to flight. +Thus, in contrast to most other mammals, in which the hind limbs greatly +preponderate in size over the fore, in the present order the fore limbs +immensely exceed the short and weak hinder extremities. The thorax, as +giving origin to the great muscles which sustain flight, and containing +the proportionately large lungs and heart, is remarkably capacious, and +the ribs are flattened and close together; the shoulder-girdle is also +greatly developed in comparison with the weak pelvic bones. + +Linnæus included the Bats among the Primates, mainly on account of the +number of their upper incisors, supposed to be always four, the thoracic +position of the mammæ, and the pendent condition of the penis. Many +other zoologists, taking into consideration the placental characters and +the form of the uterus, have followed him; but it is evident that the +situation of the mammæ is related to the necessarily central position of +the young during flight, the shortness of the uterine cornua, observable +in so many species, to the generally uniparous gestation requiring less +room, while the discoidal deciduate placenta is equally present in and +characteristic of the Insectivora, many species of which also have the +penis pendent. Thus, the reasons for maintaining the Bats in this high +position being disposed of, we find in the low organisation of their +brain a proof of their inferior status; while furthermore, although they +differ widely from all other mammals in external form, it is evident that +this is only the result of special adaptation to aerial locomotion; and, +taking into account their whole bodily structure, we may accept the view +of Professor Huxley that they should merely be regarded as exceedingly +modified Insectivora. + +So thoroughly, however, has this adaptation for flight been carried out +that of all animals the Bats are the least terrestrial, not one of them +being equally well fitted for progression on the earth. This is due to +the hind as well as the fore limbs being pressed into the service of +aerial locomotion. Thus the hind limb is so rotated outwards by the +wing-membrane that, contrary to what obtains in all other vertebrates, +the knee is directed backwards, and corresponds in position to its serial +homologue the elbow. It necessarily follows from this arrangement that +when a Bat is on the ground it rests on all fours, having the knees +directed upwards; while, in order to bring it into a position for forward +progression, the foot rotates forwards and inwards on the ankle. Walking +under these circumstances is at best only a kind of shuffle, and that +this is fully recognised by the animal is evidenced by its great anxiety +to take wing, or, if this be impracticable, to ascend to some point +where it can hitch itself up by the claws of the hind legs in its usual +position when at rest. + +[Illustration: FIG. 297.—Skeleton and flying-membranes of the Noctule +Bat (_Vesperugo noctula_). × ⅓. _c_, Clavicle; _h_, humerus; _r_, +radius; _u_, ulna (rudimentary); _d¹_, pollex; _d²_, _d³_, _d⁴_, _d⁵_, +other digits of the manus supporting _wm_, the wing-membrane; _m_, _m_, +metacarpal bones; _ph¹_, first phalanx; _ph²_, second phalanx; _ph³_, +third phalanx; _am_, antebrachial membrane; _f_, femur; _t_, tibia; _fb_, +fibula (rudimentary); _c_, calcar supporting _im_, the interfemoral +membrane; _pcl_, postcalcaneal lobe.] + +The bones of the skeleton are characterised by their slenderness and +the great size of the medullary canals in those of the extremities. +The vertebral column is short, and the vertebræ differ very slightly +in number and form throughout the species. The general number of the +dorso-lumbar vertebræ is 17, of which 12 are dorsal; the cervicals are +very broad, but short from before backwards, their breadth being due to +the great transverse diameter of the spinal canal rendered necessary by +the comparatively large size of the spinal cord, which, after giving off +the nerves to the fore limbs and thorax, rapidly diminishes in size, +and in the lumbo-sacral region is reduced to a fine thread. Except in +the frugivorous _Pteropodidæ_, the vertebræ, from the third cervical +backwards, are devoid of neural spines. From the first dorsal to the +last lumbar vertebra the spinal column forms a single curve backwards, +which is most pronounced in the lumbar region. The centra of the vertebræ +are but slightly movable upon each other, and in old individuals appear +to become partially ankylosed together. The caudal vertebræ are simple +cylindrical bones without processes; their number and length being +extremely variable even in closely allied species; and the anterior +caudals are generally united to the ischial tuberosities. The relative +development of the caudal vertebræ is, indeed, intimately correlated +to the habits of the animals; the long tail in the insectivorous forms +supporting and controlling the position of the large interfemoral +membrane, which appears not only to aid their rapid motions when in +pursuit of their prey by acting as a rudder, but also to assist in the +capture and retention of the larger insects. In the frugivorous types, +on the other hand, this is not required, and the tail is accordingly +rudimentary or absent. In all Bats the presternum has a prominent keel +for the attachment of the great pectoral muscles. In most species the +ribs are much flattened, and in some they are partially ankylosed by +their contiguous margins. + +The skull is subject to considerable structural variations, even +within the limits of a single family. Postorbital processes to the +frontals are found only in the _Pteropodidæ_, and some _Nycteridæ_ and +_Emballonuridæ_. _Pteropus leucopterus_ and _Pteralopex_ are peculiar in +having the orbit completely surrounded by bone. A slender zygomatic arch +is present, except in some of the _Phyllostomatidæ_. + +The milk-teeth are peculiar in that they are utterly unlike those of the +permanent series. They are slender, with sharp recurved cusps; and as a +rule are shed at an early period (in the _Rhinolophidæ_ before birth), +but may coexist with some of the fully developed permanent teeth. The +permanent teeth are subject to great variation of form, although they +always have distinct roots. In the Insectivorous types they are acutely +cusped, the cusps in those of the upper jaw being arranged in a more or +less distinct W; but in the frugivorous forms, like the _Pteropodidæ_ and +some of the _Phyllostomatidæ_, the molars are longitudinally grooved or +hollowed out. + +The pectoral girdle maintains a very constant type. Thus the clavicle is +very long, strong, and curved; and the scapula large, oval, triangular, +with a long curved coracoid process. The humerus, though long, is +scarcely two-thirds the length of the radius. The ulna is rudimentary, +its proximal extremity, which articulates with but a small part of the +humerus, being ankylosed to the radius; and immediately beyond the joint +it is reduced to a slender splint-like bone, extending about as far +as the middle of the radius. In all species a detached sesamoid bone +exists in the tendon of the triceps muscle. The radius is very long, +in some species actually equal to the length of the head and body. The +proximal row of the carpus consists of a single bone formed by the united +scaphoid, lunar, and cuneiform; which, with the extremity of the radius, +forms the radio-carpal joint. In the distal row the trapezium, trapezoid, +and magnum vary in size in the different families, the unciform appearing +to be the most constant, and the pisiform being generally very small. + +The manus is always furnished with five digits. The first, fourth, and +fifth digits consist of a metacarpal and two phalanges; but in the +second and third digits the number of phalanges is different in certain +families. The pollex always terminates in a claw, which—like the proximal +phalanx—is best developed in the frugivorous species. In most of the +frugivorous _Pteropodidæ_ the second digit is provided with a claw; but +in all other Bats this and the remaining digits are unarmed. In the +genus _Triænops_ alone a very peculiar short bony process projects from +the outer side of the proximal extremity of the terminal phalanx of the +fourth digit. The relative development of the digits and their phalanges +will be noticed under each family. + +As might be expected from the small size of the posterior limbs, the +pelvic girdle is relatively weak. The ilia are long and narrow. In the +males of most species the pubic bones of opposite sides are very loosely +united in front, while in females they are widely separated; and in +the family _Rhinolophidæ_ alone do these bones form a symphysis. The +ileo-pectineal eminence develops a long pectineal process, which in the +subfamily _Hipposiderinæ_ is continued forwards to the anterior extremity +of the ilium enclosing a preacetabular foramen unique among mammals. The +acetabulum is small and directed outwards and slightly upwards; and with +this is related the peculiar position of the hind limb already noticed +as one of the chief characteristics of the order. The femur is slender +and cylindrical, with a small head and very short neck, and scarcely +differs in form throughout the order. The bones of the leg and foot are +variable; in the subfamily _Molossinæ_ alone is there a well-developed +fibula, while in all other species this bone is either very slender, or +cartilaginous and ligamentous in its upper third, or reduced to a small +bony process above the heel, as in _Megaderma_, or altogether absent, as +in _Nycteris_. + +The foot consists of a very short tarsus, and of slender, laterally +compressed toes, with much curved claws. The hallux is composed of a +metacarpal, a proximal and an ungual phalanx, and is slightly shorter +than the other four toes, each of which has an additional phalanx, except +in the subfamily _Hipposiderinæ_ and in the anomalous genera _Thyroptera_ +and _Myxopoda_, where all the toes have the same number of phalanges as +the first digit, and are equal to it in length. In the genus _Chiromeles_ +the first digit is thumb-like and separated from the others, and in the +typical _Molossinæ_ the first and fifth digits are much thicker than the +intermediate toes. + +The most noticeable peculiarities in the myology of the order consist in +the separated bands or slips into which the platysma is divided, and in +the presence of the remarkable muscle termed occipito-pollicalis, which +extends from the occipital bone to the base of the terminal phalanx of +the pollex. + +Although, as already mentioned, the brain presents a low type of +organisation, yet probably no animals possess so delicate a sense of +touch as the Chiroptera. It is undoubtedly this perceptive power which +enabled the individuals deprived of sight, hearing, and smell, in +Spallanzani’s well-known experiments, to avoid the numerous threads hung +across the rooms in which they were permitted to fly about. In the +common Bats the tactile organs evidently exist, not only in the delicate +vibrissæ which spring from the sides of the muzzle, but also in the +highly sensitive and widely extended integumentary structures entering +into the formation of the wing-membranes and ear-conchs; while in many +other species, notably in the tropical Rhinolophine and Phyllostomatine +Bats, peculiar foliaceous cutaneous expansions surrounding the nasal +apertures or extending backwards behind them are added. These structures, +collectively known as the “nose-leaf” (whence the term “leaf-nosed +Bats”), have been shown by Dr. Dobson to be made up partly of the +extended and thickened marginal integument of the nostrils, and partly of +the highly differentiated glandular eminences occupying the sides of the +muzzle, in which, in all the common Bats, the vibrissæ are implanted. + +In all species of leaf-nosed Bats, and especially in the _Rhinolophidæ_, +where the nasal appendages reach their highest development, the superior +maxillary division of the fifth nerve is of remarkably large calibre. +The nasal branch of this nerve, which is given off immediately beyond +the infraorbital foramen, is by far the largest portion; the palpebral +and labial branches consisting of a few slender nerve-fibres only. This +branch passes forwards and upwards on the side of the maxilla, but soon +spreads out into numerous filaments extending into the muscles and +integument above, and into the base of the nose-leaf. The nerve supply +of the nose-leaf is further augmented by the large nasal branch of the +ophthalmic division of the fifth nerve. While the many foliations, +elevations, and depressions which vary the form of the nose-leaf +greatly increase the sensory surface supplied by the fifth nerve, and +during rapid flight intensify the vibrations conveyed to it, the great +number of sweat and oil glands which enter into its structure perform +a function analogous to that of the glands of the auditory canal in +relation to the membrana tympani in maintaining its surface in a highly +sensitive condition. The nasal appendages of the Chiroptera may thus be +regarded as performing the office of an organ of a very exalted sense +of touch standing in the same relation to the nasal branches of the +fifth nerve as the aural apparatus to the auditory nerve; for, as the +latter organ collects and transmits the waves of sound, so the former +receives impressions arising from vibrations communicated to the air by +approaching objects. + +In no order of mammals is the ear-conch so greatly developed or so +variable in form. Thus in most of the insectivorous species the ears +are longer than the head, while in some, as in the common Long-eared +Bat (_Plecotus auritus_), their length nearly equals that of the head +and body. The form of the conch is very characteristic of the various +families; in most the tragus is remarkably large, in some extending +nearly to the outer margin of the conch; and its function appears to be +to cause undulations in the waves of sound, and so intensify and prolong +them. It is worthy of notice that in the _Rhinolophidæ_, the only family +of insectivorous Bats wanting the tragus, the auditory bullæ reach their +greatest size, and the highly sensitive nasal appendages their highest +development; and that in the typical group of the _Molossinæ_ the +ear-conch is divided by a prominent keel; and the antitragus is unusually +large in those species in which the tragus is minute (see Fig. 298, _a_). +In the frugivorous Bats the form of the ear-conch is very simple, and but +slightly variable, throughout the various types. + +[Illustration: FIG. 298.—Head of _Molossus glaucinus_. (From Dobson, +_Proc. Zool. Soc._ 1876.) _a_, Antitragus; _b_, keel of the ear-conch; +_c_, notch behind antitragus.] + +In all Bats the ears are extremely mobile, each moving independently at +the will of the animal. This has been observed even in the frugivorous +_Pteropodidæ_, in which the peculiar vibratory movements first noticed in +_Artibeus perspicillatus_ may also be seen when the animals are alarmed. + +The opening of the mouth is anterior in most species, but in many it is +inferior, the extremity of the nose being more or less produced beyond +the lower lip,—so much so indeed in the small South-American species +_Rhynchonycteris naso_ as to resemble that of the Shrews. The lips +exhibit the greatest variety in form, which will be referred to under +each family. The absence of a fringe of hairs is characteristic of all +fruit-eating Bats, and probably always distinguishes them from the +insectivorous species, which they may resemble in the form of their teeth +and other respects. + +The œsophagus is narrow in all species, and especially so in the +sanguivorous Desmodont _Phyllostomatidæ_. The stomach presents two +principal types of structure, which correspond respectively to the two +great divisions of the order, the Megachiroptera and the Microchiroptera; +in the former (with the exception of _Harpyia_) the pyloric extremity +is more or less elongated and folded upon itself, in the latter it is +simple, as in the Insectivora Vera; a third exceptional type is met with +in the Desmodont _Phyllostomatidæ_, where the left or cardiac extremity +is greatly elongated, forming a long narrow cæcum-like appendage. +The intestine is comparatively short, varying from one and a half +to four times the length of the head and body, being longest in the +frugivorous and shortest in the insectivorous species. Only in _Rhinopoma +microphyllum_ and _Megaderma spasma_ has a very small cæcum been found. + +The liver is characterised by the great size of the left lateral lobe, +which occasionally equals half the size of the whole organ; the right +and left lateral fissures are usually very deep; in the Megachiroptera +(_Harpyia_ excepted) the Spigelian lobe is ill-defined or absent, and +the caudate is generally very large; but in the Microchiroptera, on the +other hand, the Spigelian lobe is very large, while the caudate is small, +in most species forming a ridge only. The gall-bladder is generally +well developed and attached to the right central lobe, except in the +_Rhinolophidæ_, where it is connected with the left central. + +In most species the hyoids are simple, consisting of a chain of +slender, elongated, cylindrical bones connecting the small basi-hyoid +with the cranium, while the pharynx is short, the larynx shallow with +feebly developed vocal cords, and guarded by a short, acutely-pointed +epiglottis, which in some genera (_Harpyia_, _Vampyrus_) is almost +obsolete. In _Epomophorus_, however, we find a remarkable departure +from the general type. Thus the pharynx is long and very capacious; the +aperture of the larynx is far removed from the fauces, and, opposite to +it, opens a canal, leading from the narial chambers, and extending along +the back of the pharynx; the laryngeal cavity is spacious and its walls +are ossified; the hyoid bone is quite unconnected, except by muscle, with +the cranium; the ceratohyals and epihyals are cartilaginous and greatly +expanded, entering into the formation of the walls of the pharynx, and in +the males of three species at least, supporting the orifices of a large +pair of air-sacs communicating with the pharynx (Fig. 299). + +[Illustration: FIG. 299.—Head and neck of _Epomophorus franqueti_ (adult +male, natural size). The anterior (_a.ph.s_) and posterior (_p.ph.s_) +pharyngeal sacs are opened from without, the dotted lines indicating the +points where they communicate with the pharynx; _s_, thin membranous +septum in middle line between the anterior pharyngeal sacs of opposite +sides; _s.m._, sterno-mastoid muscle separating the anterior from the +posterior sac. (Dobson, _Proc. Zool. Soc._ 1881.)] + +In extent, peculiar modifications, and sensitiveness the cutaneous +system reaches its highest development in this order. As a sensory organ +its chief modifications in connection with the external ear and with the +nasal and labial appendages have been described when referring to the +nervous system. It remains therefore to consider its relative development +as part of the organs of flight. + +The extent and shape of the flying-membranes depend mainly on the form of +the bones of the anterior extremities, and on the presence or absence of +the tail. Certain modifications of these membranes, however, are met with +which do not depend on the skeleton, but are related to the habits of the +animals, and to the manner in which the wing is folded in repose. + +These membranes consist of the “antebrachial membrane,” extending from +the point of the shoulder along the humerus and more or less of the +forearm to the base of the pollex, the metacarpal bone of which is +partially or wholly included in it; the “wing-membrane,” which is spread +out between the greatly elongated fingers, and extends along the sides +of the body to the posterior extremities, generally reaching to the +feet; and the “interfemoral membrane,” the most variable of all, which +is supported between the extremity of the body, the legs, and the calcar +(Fig. 297). + +[Illustration: FIG. 300.—Frontal sac and nose-leaf in male and female of +_Hipposiderus larvatus_. (Dobson, _Proc. Zool. Soc._ 1873.)] + +The antebrachial and wing-membranes are most developed in those species +fitted only for aerial locomotion, which when at rest hang with the body +enveloped in the wings; but in the family _Emballonuridæ_, and especially +in the subfamily _Molossinæ_ (the species of which are the best fitted +of all Bats for terrestrial progression), the antebrachial membrane is +reduced to the smallest size, and is not developed along the forearm, +leaving also the pollex quite free, and the wing-membrane is very +narrow and folded in repose completely under the forearm. The relative +development of the interfemoral membrane has been referred to above +in describing the caudal vertebræ. Its small size in the frugivorous +and sanguivorous species, in which its presence would be injurious as +impeding their motions when searching for food as they hang suspended +by their feet, is easily understood. Odoriferous glands and pouches +opening on the surface of the outer skin are developed in many species, +but in most cases more so in males than in females, and thus constitute +secondary sexual characters, which will be referred to when treating of +the peculiarities of certain species. + +All the fossil Chiroptera at present known are true Bats in every sense +of the word, and therefore throw no light on the origin of the order. +The earliest representatives of the order occur in beds of Upper Eocene +(Lower Oligocene) age. + +The order is divided by Dobson into the suborders Megachiroptera and +Microchiroptera. + + +_Suborder_ MEGACHIROPTERA. + +Frugivorous Bats, generally of large size. Crowns of molars smooth, +marked with a longitudinal groove (cuspidate in _Pteralopex_); bony +palate continued behind the last molar, narrowing slowly backwards; three +phalanges in the index finger, the third phalanx generally terminated by +a claw; sides of the ear-conch forming a complete ring at the base; tail, +when present, inferior to (not contained in) the interfemoral membrane; +pyloric extremity of the stomach generally much elongated; the Spigelian +lobe of the liver ill-defined or absent, and the caudate well developed. + +Limited to the tropical and subtropical parts of the eastern hemisphere. + +Mr. O. Thomas[571] considers that the ordinary type of molar dentition +found in this suborder is a specialised adaptation from the cuspidate +type of the Microchiroptera; the genus _Pteralopex_ retaining the +ancestral form of teeth. + + +_Family_ PTEROPODIDÆ. + +Since all the forms are included in this family its characters may be +taken to be the same as those of the suborder. + +Subfamily =Pteropodinæ=.—Tongue moderate; molars well developed. + +_Epomophorus._[572]—Dentition: _i_ ²⁻¹⁄₂, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ¹⁄₂; +total 28 or 26. Tail absent or very short, when present free from +interfemoral membrane; second digit of manus clawed; premaxillæ united. +This genus includes some seven species inhabiting Africa south of the +Sahara. The head is large and long, and the lips are expansible, and +frequently with peculiar folds. The ears have a white tuft of hair on +the margin; and in the males of most species there are large glandular +pouches in the skin of the side of the neck near the shoulder, from the +mouth of which project long and coarse yellowish hairs, forming tufts +on the shoulders, from which the genus takes its name. Another male +secondary sexual character consists in the presence of a pair of large +air-sacs extending outwards on each side from the pharynx beneath the +integument of the neck, in the position shown in Fig. 299. These sacs +are evidently capable of being greatly distended at the will of the +animal, and their inflation probably occurs under the same circumstances +that the wattles of male gallinaceous birds swell up, namely, when +engaged in courting the females. Other remarkable conditions in which +these Bats appear to differ from all other species occur in the form of +the hyoid bones and larynx. These Bats appear to live principally on +figs, the juicy contents of which their large lips and capacious mouths +enable them to swallow without loss. + +[Illustration: FIG. 301.—Head of Fox-Bat (_Pteropus personatus_). From +Gray, _Proc. Zool. Soc._ 1866.] + +_Pteropus._[573]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ²⁄₃; total 34. +This genus has more than forty species, and thus includes more than half +the members of the family. All are of large size, and the absence of a +tail, the long pointed muzzle (Fig. 301), and the woolly fur covering the +neck render their recognition easy. They are commonly known as “Flying +Foxes,” or Fox-Bats; and one of the species (_P. edulis_) inhabiting Java +measures 5 feet across the fully extended wings, and is thus the largest +known species of the order. All the species closely resemble one another +in dentition, and are mainly distinguished by the form of the ears and +the quality of the fur. _P. scapulatus_, from North-East Australia, +approaches the species of the second subfamily in the remarkable +narrowness of its molars and premolars. + +The range of this genus extends from Madagascar and the neighbouring +islands through the Seychelles to India, Ceylon, Burma, the Malay +Archipelago, Southern Japan, New Guinea, Australia, and Polynesia (except +the Sandwich Islands, Ellice’s Group, Gilbert’s Group, Tokelau, and the +Low Archipelago). Of the islands inhabited by it some are very small and +remote from any continent, such as Savage Island in the South Pacific and +Rodriguez in the Indian Ocean. Although two species inhabit the Comoro +Islands, which are scarcely 200 miles from the African coast, not a +single species is found in Africa; but in India, separated by thousands +of miles of almost unbroken ocean, a species exceedingly closely allied +to the common Madagascar Fox-Bat is abundant. The Malay Archipelago +and Australia are their headquarters; and in some places they occur in +countless multitudes. Mr. Macgillivray remarks of _P. conspicillatus_: +“On the wooded slope of a hill on Fitzroy Island I one day fell in with +this Bat in prodigious numbers, looking while flying in the bright +sunshine (so unusual for a nocturnal animal) like a large flock of rooks. +On close approach a strong musky odour became apparent, and a loud +incessant chattering was heard. Many of the branches were bending under +their load of Bats, some in a state of inactivity, suspended by their +hind claws, others scrambling along among the boughs, and taking to wing +when disturbed.” + +[Illustration: FIG. 302.—Female and young of _Xantharpyia collaris_. +(From Sclater, _Proc. Zool. Soc._ 1870, p. 127.)] + +_Xantharpyia._[574]—Dentition as in _Pteropus_, but a short tail present, +and the fur on the back of the neck similar to that of the body. This +genus is represented by some nine species, which have a distribution very +similar to that of _Pteropus_, except that they extend into Africa, and +are not found in Australia and Polynesia. _X. ægyptiaca_ inhabits the +chambers of the Great Pyramid and other deserted buildings in Egypt, and +is probably the species so generally figured in Egyptian frescoes. Fig. +302 exhibits an African species of this genus in the attitude assumed by +the Fox-Bats when at rest. + +_Boneia._[575]—This genus, as represented by _B. bidens_ of Borneo, +differs from _Xantharpyia_ in having only a single pair of upper incisors. + +_Cynopterus._[576]—Dentition: _i_ ²⁄₂₋₁, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ²⁄₂; total +32 or 30. Muzzle short, grooved like _Pteropus_ in front; tail and fur +generally as in _Xantharpyia_, but the former sometimes wholly absent. +This genus, with seven species, is almost limited to the Oriental region. +_C. marginatus_ is very common in India, and extremely destructive to +ripe fruit of every description. Dr. Dobson states that “he gave to a +specimen of this Bat obtained at Calcutta a ripe banana, which, with the +skin removed, weighed exactly 2 ounces; the animal immediately, as if +famished with hunger, fell upon the fruit, seizing it between the thumbs +and the index fingers, and took large mouthfuls out of it, opening the +mouth to the fullest extent with extreme voracity. In the space of three +hours the whole fruit was consumed. Next morning the Bat was killed, and +found to weigh one ounce, or half the weight of the food eaten in three +hours. Indeed the animal when eating seemed to be a kind of living mill, +the food passing from it almost as fast as devoured, and apparently +unaltered, eating being, as it were, performed only for the pleasure of +eating.” + +_Harpyia._[577]—Dentition: _i_ ¹⁄₀, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ²⁄₂; total 24. +Premaxillæ well developed and united in front; facial bones much elevated +above the margin of the jaw, nostrils tubular (Fig. 303); body and +limbs as in _Cynopterus_. Includes two species from the Austro-Malayan +sub-region, readily recognised by the peculiar tubular and projecting +nostrils, as shown in the accompanying woodcut. + +[Illustration: FIG. 303.—Head of _Harpyia major_. (From Dobson, _Proc. +Zool. Soc._ 1877.)] + +_Cephalotes._[578]—Dentition: _i_ ¹⁄₁, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ²⁄₃; total +28. Premaxillæ separate in front; nostrils simple; muzzle short; index +finger without a claw; tail short. Includes one species, having the same +distribution as _Harpyia_. The wing-membrane arises from the middle line +of the back, to which it is attached by a longitudinal very thin process +of the integument; the wings are quite naked, but the back covered by +them is clothed with hair. + +_Pteralopex._[579]—External characters as in _Pteropus_; ears short +and hairy; wings arising from the middle line of the back. Muzzle very +short; plane of orbit directed more upwards than in _Pteropus_; orbit +surrounded by bone; sagittal crest strongly developed. Teeth cuspidate; +upper incisors with broad posterior ledges; upper canine short and thick, +with a stout secondary cusp in the middle of the posterior border, and +two smaller postero-internal basal cusps; cheek-teeth short and broad, +with their anterior and posterior basal ledges so developed and the main +cusps so nearly conical as to obliterate the longitudinal grooving of +_Pteropus_. Lower incisors very disproportionate, the outer pair being +nearly twenty times the bulk of the inner; lower canine stout, with a +simple posterior basal ledge. Represented by _P. atrata_ of the Solomon +Islands. As already mentioned, Mr. Thomas regards the dentition of this +genus as the most generalised type found in the suborder. + +Subfamily =Carponycterinæ=.—Facial part of skull much produced; molars +narrow, and scarcely raised above the gum; and the tongue exceedingly +long, attenuated in the anterior third, and armed with long recurved +papillæ near the tip. + +_Notopteris._[580]—Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ²⁄₂; total +28. Index finger without a claw; wings arising from the middle line of +the back; tail long; first upper premolar long, with two roots. The +single representative of the genus, _N. macdonaldi_, inhabits the Fiji +Islands, Aneiteum Island, and New Guinea. It is at once distinguished +from all other Bats of this family by the length of its tail, which is +nearly as long as the forearm. + +_Eonycteris._[581]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ²⁄₃; +total 34. First upper premolar small, with a single root. This genus +is likewise represented by a single species (_E. spelæa_), from the +Farm Caves, Moulmein, Burma, which has somewhat the appearance of +_Xantharpyia_; but the absence of a claw to the index finger and the +characteristic tongue and teeth at once distinguish it. + +_Carponycteris_[582] and _Melonycteris_,[583] each with a single +species, are closely allied; the index finger in both has a claw, and +the number of the teeth is the same as in _Eonycteris_. _Carponycteris +minima_ is the smallest known species of the suborder, being much smaller +than the common Noctule Bat of Europe, and its forearm scarcely longer +than that of the Long-eared Bat. It is nearly as common in certain +parts of India as _Cynopterus marginatus_ (compared with which it is +proportionally equally destructive to fruit), and extends eastward +through the Malay Archipelago as far as New Ireland, where it is +associated with _Melonycteris melanops_, distinguished from it by its +larger size and the total absence of the tail. + +_Nesonycteris._[584]—Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ²⁄₃; total +32. Allied to _Melonycteris_, but distinguished by the absence of the +inner pair of lower incisors, and of a claw to the index finger. Tail +wanting. Represented by _N. woodfordi_, of the Solomon Islands. + +_Callinycteris._[585]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃; +total 32. Allied to the preceding, but with a short tail; no claw to +index. One species from Celebes. + +_Trygenycteris._[586]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ²⁄₃; +total 34. No external tail; a claw on index. One species from West Africa. + + +_Suborder_ MICROCHIROPTERA. + +Insectivorous (rarely frugivorous or sanguivorous) Bats, of comparatively +small size. Crowns of molars acutely cusped, marked by transverse +grooves; bony palate narrowing abruptly, not continued backwards +laterally behind the last molar; one rudimentary phalanx (rarely two +phalanges or none) in the index finger, which is never terminated +by a claw; outer and inner sides of ear-conch commencing inferiorly +from separate points of origin; tail, when present, contained in the +interfemoral membrane, or appearing upon its upper surface; stomach +simple (except in the Desmodont _Phyllostomatidæ_); Spigelian lobe of the +liver very large, and the caudate generally small. Inhabit the tropical +and temperate regions of both hemispheres. The members of this suborder +may be divided into two sections. + + +_Section_ VESPERTILIONINA. + +Tail contained within the interfemoral membrane; the middle pair of upper +incisors never large, and separated from each other by a more or less +wide space. Middle finger with two osseous phalanges only (except in +_Myxopoda aurita_, _Thyroptera tricolor_, and _Mystacops tuberculatus_). +First phalanx of the middle finger extended (in repose) in a line with +the metacarpal bone. + + +_Family_ RHINOLOPHIDÆ. + +In all the species of this family the nasal appendages are highly +developed, and surround the sides of the nasal apertures, which are +situated in a depression on the upper surface of the muzzle; the ears are +large and generally separate, without trace of a tragus; the premaxillæ +are rudimentary, suspended from the nasal cartilages, and supporting +a pair of very small incisors; the molars have acute W-shaped cusps; +the skull is large, and the nasal bones which support the large nasal +cutaneous appendages are much expanded vertically and laterally; in +the females a pair of teat-like appendages are found in front of the +pubis; and the tail is long and produced to the posterior margin of the +interfemoral membrane. This family is found in the temperate and tropical +parts of the eastern hemisphere. + +From whatever point of view the _Rhinolophidæ_ may be considered, they +are evidently the most highly organised of insectivorous Bats. In them +the osseous and cutaneous systems reach the most elaborate development. +Compared with those of the present family the bones of the extremities +and the flying-membranes of other Bats appear coarsely formed, and +even their teeth seem less perfectly fitted to crush the hard bodies +of insects. The very complicated nasal appendages, which evidently act +as delicate organs of special perception, here reach their highest +development, and the differences in their form afford valuable characters +in the discrimination of the species, which resemble one another very +closely in dentition and in the colour of the fur. + +Subfamily =Rhinolophinæ=.—First toe with two, other toes with three, +phalanges each; ilio-pectineal spine not connected by bone with the +antero-inferior surface of the ilium. + +[Illustration: FIG. 304.—Head of Indian Horse-shoe Bat (_Rhinolophus +mitratus_). (From Dobson, _Monogr. Asiat. Chiropt._)] + +_Rhinolophus._[587]—Dentition: _i_ ¹⁄₂, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; +total 32. Nose-leaf (Fig. 304) with a central process behind and +between the nasal orifices, posterior extremity lanceolate, antitragus +large. Includes more than twenty species. _R. luctus_, in which the +forearm has a length of 3 inches, is the largest species, inhabiting +elevated hill tracts in India and Malayana; _R. hipposiderus_ of Europe, +extending into South England and Ireland, forearm 1·5 inches, is one +of the smallest; and _R. ferrum-equinum_, with the forearm 2·3 inches +in length, represents the average size of the species, which are +mainly distinguished from one another by the form of the nose-leaf. +The last-named species extends from England to Japan, and southward to +the Cape of Good Hope. The genus is represented in the Himalaya by the +closely allied _R. tragatus_, distinguished by having three vertical +grooves on the lower lip, in place of the single groove found in _R. +ferrum-equinum_. _Rhinolophus_ is represented in the Upper Eocene +Phosphorites of Central France by _R. antiquus_ and _R. dubius_; the +former appears to have the same dental formula as in the existing +species, but differs slightly in the structure of some of the lower +molars, so that it is separated generically by some writers under the +name of _Pseudorhinolophus_. The face is also longer than in existing +forms, and there are certain differences in the structure of the skull. +_Alastor_, from the same deposits, differs from _Rhinolophus_ by the +extreme shortness of the nasal region. _Palæonycteris_, from the Lower +Miocene of France, is said to be allied to _Rhinolophus_, but the +premolars are ³⁄₃, and the limb bones are stated to resemble those of +_Molossus_. + +Subfamily =Hipposiderinæ=.—Toes equal, of two phalanges each; +ilio-pectineal spine united by a bony isthmus with a process derived from +the antero-inferior surface of the ilium. + +[Illustration: FIG. 305. Head of _Hipposiderus calcaratus_. (From Dobson, +_Proc. Zool. Soc._ 1877.)] + +_Hipposiderus._[588]—Dentition: _i_ ¹⁄₂, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂, _m_ ³⁄₃; +total 30 or 28. Tail well developed. This genus, of which more than +twenty species have been described, differs from _Rhinolophus_ in the +form of the nose-leaf, which is not lanceolate behind and is unprovided +with a central process covering the nostrils. The largest species, +_H. armiger_, appears to be the most northerly, having been taken at +Amoy in China, and in the Himalaya at an elevation of 5,500 feet. Many +of the species are provided with a peculiar frontal sac behind the +nose-leaf, rudimentary in females (Fig. 305), which the animal can evert +at pleasure; the sides of this sac secrete a waxy substance, and its +extremity supports a pencil of straight hairs. + +_Anthops._[589]—Like _Hipposiderus_, but with the tail rudimentary, +consisting merely of three or four vertebræ hidden in the base of the +interfemoral membrane. Nose-leaf very complicated, its upright transverse +portion emarginate above, and the projections rounded and hollowed +behind, and their substance quite thin. Premolars ²⁄₂. Represented by _A. +ornatus_ of the Solomon Islands. + +Mr. O. Thomas, the describer of this Bat, remarks that it is evidently +more nearly allied to the preceding than to the succeeding genera, +although it agrees with _Cœlops_ in the rudimentary tail. + +_Rhinonycteris_[590] and _Triænops_.[591]—These are two allied genera +with well-developed tails; the former being represented by _R. aurantia_ +from Australia, and the latter by _T. persicus_ from Persia and Eastern +Africa. _Triænops_ (Fig. 306) is characterised by the remarkable form of +its nasal appendages and ears, and the presence of a peculiar osseous +projection from the proximal extremity of the second phalanx of the +fourth finger. + +[Illustration: FIG. 306.—Head of _Triænops persicus_. × 2. (From Dobson, +_Monogr. Asiat. Chiropt._)] + +_Cœlops._[592]—This genus is known only by a single species, _C. frithi_, +from the Bengal Sunderbans, Java, and Siam (in the roof of the great +pagoda at Laos); and is distinguished, not only by the form of its +nose-leaf, but also by the great length of the metacarpal of the index +finger, as well as by the shortness of the calcar and interfemoral +membrane and the rudimental tail. + + +_Family_ NYCTERIDÆ. + +This small family, including only two genera of Bats of peculiar aspect, +limited to the tropical and subtropical parts of the eastern hemisphere, +is distinguished from the _Rhinolophidæ_ by the presence of a distinct +tragus to the ear, and by the premaxillæ being cartilaginous or small and +separated from one another in front by a distinct space. + +_Megaderma._[593]—Dentition: _i_ ⁰⁄₂, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂, _m_ ³⁄₃; total +28 or 26. This genus, which is represented by five species, is readily +recognised by the absence of upper incisors, the cylindrical narrow +muzzle surmounted by an erect naked cutaneous nose-leaf, the base of +which conceals the nasal orifices, by the immense connate ears with large +bifid tragi, and by the great extent of the interfemoral membrane, in +the base of which the very short tail is concealed. _M. gigas_ (Fig. +307), from Central Queensland (length of forearm 4·2 inches), is not +only the largest species of the genus but also of the suborder. _M. +lyra_, common in India (forearm 2·7 inches), has been caught in the act +of sucking the blood, while flying, from a small species of _Vesperugo_, +which it afterwards devoured, so that it is probable that the Bats of +this genus do not confine themselves to insect prey alone, but also feed, +when they can, upon the smaller species of Bats and other small mammals. + +[Illustration: FIG. 307.—_Megaderma gigas._ × ½. (From Dobson, _Proc. +Zool. Soc._ 1880.)] + +The Oriental _M. spasma_ and _M. lyra_ differ from the Ethiopian _M. cor_ +and _M. frons_ in having two upper premolars instead of one, and also in +the shape of the frontals and nasals. + +_Nycteris._[594]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total +32. This genus, of which there are seven species, differs so much from +_Megaderma_ that it may be considered the type of a separate subfamily. +As in that genus, the frontal bones are deeply hollowed out and expanded +laterally, the muzzle presents a similar cylindrical form, and the lower +jaw also projects, but the single elevated nose-leaf is absent, and +instead of it the face is marked by a deep, longitudinal, sharp-edged +groove extending from the nostrils (which are on the upper surface of +the muzzle, near its extremity) to the low band connecting the bases of +the large ears, the sides of this depression being margined as far back +as the eyes by small horizontal cutaneous appendages. All the species +resemble one another closely, and are mainly distinguished by the form +of the tragus and the size and relative position of the second lower +premolar. With the exception of _N. javanica_, they are all limited to +the Ethiopian region. + + +_Family_ VESPERTILIONIDÆ. + +Nostrils opening by simple crescentic or circular apertures at the +extremity of the muzzle, not surrounded by distinct foliaceous cutaneous +appendages; premaxillæ small, lateral, and separated by a wide space +in front; tragus distinct. In addition to these characters, it may be +observed that the skull is of moderate size, the nasal and frontal +bones not being much extended laterally or vertically, nor furrowed by +deep depressions. The number of incisors varies from ²⁄₃ to ¹⁄₃, rarely +(in _Antrozous_ only) ¹⁄₂, premolars ³⁄₃, or ²⁄₂, or ¹⁄₂, rarely (in +_Vesperugo noctivagans_ of North America) ²⁄₃; the upper incisors are +small, separated by a wide space in the middle line, and placed in pairs +or singly near the canine; the molars are well-developed, with acute +W-shaped cusps. + +This family, which may be regarded as occupying a central position in +the suborder, includes the common simple-faced Bats of all countries, +of which the well-known Pipistrelle and the Whiskered Bat (_Vespertilio +mystacinus_) may be taken as familiar types, and its species number more +than 150, or considerably more than one-third the total number of the +known species of the entire order. The various genera may be conveniently +grouped into the _Plecotine_, _Vespertilionine_, _Miniopterine_, and +_Thyropterine_ divisions. + +In the _Plecotine_ division, of which the common Long-eared Bat +(_Plecotus auritus_) is the type, the crown of the head is but slightly +raised above the face-line, the outermost upper incisor is close to the +canine, and the nostrils are margined behind by grooves on the upper +surface of the muzzle, or by rudimentary nose-leaves; the ears also are +generally very large and united. + +_Plecotus._[595]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; total +36. Outer margin of ear-conch ending abruptly near the angle of the +mouth, the inner margin with a more or less prominent rounded projection +directed inwardly above the base; tragus very large, tapering upwards, +with a lobe at the base of its outer margin, rounded, and placed half +horizontally. This genus is represented by the European Long-eared Bat +(_P. auritus_), and _P. macrotis_, restricted to North America. The +latter is distinguished by the great size of the glandular prominences of +the sides of the muzzle, which meet in the centre above and behind the +nostrils. _P. auritus_ extends over the greater part of the Palæarctic +region, occurring in Ireland in the west and the Himalaya in the east. + +_Synotus._[596]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃; total 34. +This genus is distinguished from the preceding by the loss of one lower +premolar and by the outer margin of the ear being carried forwards above +the mouth and in front of the eye; it includes the European Barbastelle +Bat (_S. barbastellus_) and _S. darjilingensis_ from the Himalaya. + +_Otonycteris._[597]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total +30. The reduction in the number of upper incisors readily characterises +this genus, which appears to connect the typical representatives of the +section, through _Scotophilus_, with the Vespertilionine division. It is +represented by a single species, _O. hemprichi_, from North Africa and +the Himalaya. + +_Nyctophilus._[598]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; +total 30. This and the following genera are distinguished from all the +preceding by the presence of a rudimentary nose-leaf. The present genus +contains _N. timoriensis_ of the Australian region, and _N. microtis_ of +New Guinea. + +_Antrozous._[599]—Dentition: _i_ ¹⁄₂, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total +28. Readily distinguished from the other members of the whole family +by having but two lower incisors, and from the other species of the +section by the separate ears. The single species, _A. pallidus_, inhabits +California. + +The _Vespertilionine_ division includes some nine-tenths of all the +representatives of the family. They are distinguished from the preceding +section by the simple nostrils, opening by crescentic or circular +apertures at the extremity of the muzzle, the generally small size of the +ears, and the absence of grooves on the forehead. + +_Vesperugo._[600]—Dentition: _i_ ²⁻¹⁄₃, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂₋₃, _m_ +³⁄₃; total 34, 30, or 36. This large genus comprises about one-third +of the section, and is divided into groups or subgenera, according to +the number of premolars and incisors; the latter varying from ²⁄₃ to +¹⁄₃ in the subgenera _Scotozous_ and _Rhogeëssa_, and the premolars +from ²⁄₂ to ¹⁄₂ (in the subgenus _Lasionycteris_ ²⁄₃). The Bats of +this genus are generally easily distinguished by their comparatively +thickly formed bodies, flat broad heads and obtuse muzzles, short, +broad, and triangular obtusely-pointed ears, obtuse and usually slightly +incurved tragus, short legs, and by the presence in most species of a +well-developed post-calcaral lobule. This lobule (which is supported +by a cartilaginous process derived from the calcar) may act as a kind +of adhesive disc in securing the animal’s grasp when climbing over +smooth surfaces. _Vesperugo_ probably contains the greatest number of +individuals among the genera of Chiroptera, and, with the exception of +_Vespertilio_, its species have also the widest geographical range, being +almost cosmopolitan; and one of the species, the well-known Serotine +(_V. [Vesperus] serotinus_) is remarkable as the only species of Bat +known to inhabit both the Old and the New World; one (_V. borealis_) +has been found close to the limits of the Arctic circle, and another +(_V. magellanicus_) inhabits the cold and desolate shores of the Straits +of Magellan, being doubtless the Bat referred to by Mr. Darwin in the +_Naturalist’s Voyage_. The Common Pipistrelle (_V. pipistrellus_), +ranging over the greater part of the Palæarctic region, is the best known +species. + +_Chalinolobus._[601]—This genus agrees with _Vesperugo_ in the dental +formula, but is readily distinguished by the presence of a well-defined +lobe projecting near the angle of the mouth from the lower lip, and +by the unicuspidate first upper incisor. The species fall into two +subgenera—_Chalinolobus_ proper, with _p_ ²⁄₂, represented by _C. morio_ +from New Zealand, Tasmania, and Australia, and three other species from +Australia; and _Glauconycteris_, with _p_ ¹⁄₂, limited to Southern +and Equatorial Africa, and known by _C. argentatus_ and two other +species, the Bats of this subgenus being especially remarkable for their +peculiarly thin membranes, traversed by very distinct reticulations and +parallel lines. + +[Illustration: FIG. 308.—Head of _Scotophilus emarginatus_. (Dobson, +_Monogr. Asiat. Chiropt._)] + +_Scotophilus._[602]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total +30. This genus comprises a comparatively small number of species nearly +allied to _Vesperugo_, and some of which approach so closely to the +aberrant types of the latter ranged under the subgenus _Scotozous_, as to +render the definition of the present genus almost impossible.[603] The +species are restricted to the tropical and subtropical regions of the +eastern hemisphere, though widely distributed within these limits. The +more typical species are distinguished especially by the single pair of +unicuspidate upper incisors separated by a wide space and placed close +to the canines, by the small transverse first lower premolar squeezed in +between the canine and second premolar, and, generally, by their conical +nearly naked muzzles and remarkably thick leathery membranes. _S. kuhli_ +is probably the commonest species of Bat in India, and appears often on +the wing even before the sun has touched the horizon, especially when +the white-ants are swarming, feeding eagerly upon them as they rise in +the air. _S. gigas_, from Equatorial Africa, with the forearm measuring +3·4 inches, is by far the largest species. _S. albofuscus_, from the +Gambia, which is readily distinguished from the other species by its +white wings, is an aberrant form, in which the lower premolars are long +and not crowded together, and thereby so closely resembles _Vesperugo_ +(_Scotozous_) _dormeri_ as to render it almost impossible to distinguish +_Scotophilus_ and _Vesperugo_. The figured species is from India. + +_Nycticejus._[604]—This genus, with the same dental formula as +_Scotophilus_, is distinguished by the first lower premolar not being +squeezed in between the adjoining teeth, and by the comparatively much +greater size of the last upper molar. It includes only the common North +American _N. humeralis_ (_crepuscularis_), a small Bat scarcely larger +than the Pipistrelle. It seems, however, as pointed out by Mr. O. Thomas, +that the discovery of _Scotophilus albofuscus_ renders the generic +distinctness of _Nycticejus_ no longer tenable, and that the species +should be known as _Scotophilus humeralis_. + +_Atalapha._[605]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂, _m_ ³⁄₃; total +32 or 30. The five species of this genus, which are confined to the +New World, are generally characterised by the interfemoral membrane +being more or less covered with hair (in the two commonest species, _A. +noveboracensis_ and _A. cinerea_, wholly covered), and by the peculiar +form of the tragus, which is expanded above and abruptly curved inwards. +These species have two upper premolars, of which the first is extremely +small and quite internal to the tooth-row. + +_Harpyiocephalus._[606]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ +³⁄₃; total 34. This genus includes some eight species of small +Bats distinguished by their prominent tube-like nostrils and hairy +interfemoral membrane. _H. suillus_, from Java and neighbouring +islands, is the best-known species, and another closely allied (_H. +hilgendorfi_)has been described by Professor Peters from Japan. The +remaining six species are known only from the Himalaya and Tibet. All +appear to be restricted to the hill tracts of the countries in which they +are found. + +_Vespertilio._[607]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total +38. Next to _Vesperugo_, this genus includes by far the largest number +of species, amounting to over forty; it has, however, rather a wider +geographical distribution in both hemispheres, one species at least being +recorded from the Navigators’ Islands. The species are easily recognised +by the peculiar character of the upper incisors, the crowns of which +diverge from each other; by the large number of premolars, of which the +second upper one is always very small; and by the oval elongated ear and +narrow attenuated tragus. In the British Isles this genus is represented +by four species, viz. Bechstein’s Bat (_V. bechsteini_); the Reddish-Gray +Bat (_V. nattereri_), of very local occurrence; Daubenton’s Bat (_V. +daubentoni_); and the Whiskered Bat (_V. mystacinus_). + +_Cerivoula._[608]—This genus, which has the same dental formula as +_Vespertilio_, is distinguished by the parallel upper incisors, and the +comparatively large size of the second upper premolar. Some ten species +have been described from the Ethiopian and Oriental regions, of which _C. +picta_, from India and the Indo-Malayan sub-region, is the best-known, +being well characterised by its brilliantly coloured orange fur and +conspicuously marked membranes, which are variegated with orange and +black. This genus includes the most delicately formed and most truly +insectivorous, tropical, forest-haunting Bats, which appear to stand +as regards the species of _Vespertilio_ in a position similar to that +occupied by _Chalinolobus_ with respect to _Vesperugo_. + +[Illustration: FIG. 309.—Side and front views of the head of _Cerivoula +hardwickei_. (Dobson, _Monogr. Asiat. Chiropt._)] + +The _Miniopterine_ division includes only two genera, and is +characterised by the great elevation of the crown of the head above the +facial line, and also by the upper incisors being separated from the +canine and also in the middle line. + +_Natalus._[609]—This genus, while having the divisional characters +mentioned above, agrees in the dental formula and its general external +form with _Cerivoula_, from which it is distinguished by the short +triangular tragus. It includes three species, restricted to South and +Central America and the West Indies; the head of _N. micropus_ being +shown in Fig. 310. + +[Illustration: FIG. 310.—Head of _Natalus micropus_. × 3. (Dobson, _Proc. +Zool. Soc._ 1880.)] + +_Miniopterus._[610]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; total +36. In addition to the difference in the number of the teeth, this genus +is distinguished by the shortness of the first phalanx of the middle +finger and the great length of the tail, which is wholly contained +within the interfemoral membrane; it includes four species, restricted +to the eastern hemisphere. Of these the best-known, _M. schreibersi_, +is very widely distributed, being found almost everywhere throughout +the tropical and warmer temperate regions of the eastern hemisphere; +specimens from Germany, Madagascar, Japan, and Australia differing in no +appreciable respect from one another. + +The last or _Thyropterine_ division, which likewise comprises only two +genera, is characterised by the presence of an additional osseous phalanx +in the middle finger and an equal number of phalanges in the toes, and +also by peculiar accessory clinging organs attached to the extremities. + +_Thyroptera._[611]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total +38. In the single species _T. tricolor_ of Brazil the clinging organs +have the appearance of small, circular, pedunculated, hollow discs (Fig. +311), resembling in miniature the sucking cups of cuttle-fishes, and are +attached to the inferior surfaces of the thumbs and soles of the feet. +With these the animal is enabled to maintain its hold when creeping over +smooth vertical surfaces. + +[Illustration: FIG. 311.—Suctorial discs in _Thyroptera tricolor_. _a_, +Side and _b_, concave surface, of thumb-disc; _c_, foot with disc, and +calcar with projections (all much enlarged). Dobson, _Proc. Zool. Soc._ +1876.] + +_Myxopoda._[612]—The second genus is likewise represented only by a +single species—_M. aurita_ of Madagascar—and is distinguished from the +preceding by the characters of the teeth and the form of the ears. +The whole inferior surface of the pollex supports a large sessile +horse-shoe-shaped adhesive pad, with the circular margin directed +forwards and notched along its edge, and a smaller pad occupies part of +the sole of the foot. + +_Fossil Vespertilionidæ._—It is not improbable that _Vesperugo_ is +represented in the Upper Eocene of the Paris basin by _V. parisiensis_, +which appears to be allied to _V. serotina_, although it has been +regarded by some writers as generically distinct, under the name of +_Nyctitherium_. _Vesperugo_ (_Nyctitherium_) also occurs in the Bridger +Eocene of the United States; _Nyctilestes_ from the same deposits being +an allied extinct genus. A number of European Miocene species have been +referred to _Vespertilio_, but the term in these cases must be used in +a somewhat wide sense. _Vespertiliavus_, of the Phosphorites of Central +France, differs from _Vespertilio_ in the proportions of its premolars. + + +_Section_ EMBALLONURINA. + +Tail perforating the interfemoral membrane and appearing on its upper +surface, or produced considerably beyond the truncated membrane; the +middle pair of upper incisors generally large and close together. + + +_Family_ EMBALLONURIDÆ. + +First phalanx of the middle finger folded (in repose) on the dorsal +surface of the metacarpal bone (except in _Noctilio_ and _Mystacops_). +Nostrils opening by simple circular or valvular apertures at the +extremity of the muzzle, not surrounded or margined by foliaceous +cutaneous appendages; tragus distinct. + +The _Emballonuridæ_ are generally easily distinguished by the peculiar +form of the muzzle, which is obliquely truncated, the nostrils projecting +more or less in front beyond the lower lip; by the first phalanx of the +middle finger being folded in repose forwards on the upper surface of the +metacarpal bone; by the tail, which either perforates the interfemoral +membrane or is produced far beyond it; and by the upper incisors, which +are generally a single pair separated from the canine and also in the +middle line. The family is cosmopolitan like the _Vespertilionidæ_, but +rarely extends north or south of the thirtieth parallel of latitude. + +Subfamily =Emballonurinæ=.—Tail slender, perforating the interfemoral +membrane, and appearing upon its upper surface, or terminating in it; +legs long, fibula very slender; upper incisors weak. + +In the _Furipterine_ division the tail terminates in the interfemoral +membrane; the crown of the head is greatly elevated above the face-line; +the thumb and first phalanx of the middle finger are very short; and the +dentition is _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; total 38. + +Represented by two genera, _Furipterus_[613] and _Amorphochilus_,[614] +each including one species of peculiar aspect; the latter distinguished +from the former by the widely separated nostrils and the great extension +backwards of the bony palate. Habitat South America. + +In the typical or _Emballonurine_ division part of the tail is included +in the basal half of the interfemoral membrane, the remaining part +passing through and appearing upon its upper surface; the crown of the +head is slightly elevated; the pollex and first phalanx of the middle +finger are moderately long; and the number of the premolars is always ²⁄₂. + +_Emballonura._[615]—Incisors ²⁄₃. Extremity of the muzzle more or less +produced beyond the lower lip, forehead flat. Contains some five species, +inhabiting islands from Madagascar through the Malay Archipelago to the +Navigators’ Islands. + +[Illustration: FIG. 312.—Ear of _Emballonura raffrayana_, × 2. (Dobson, +_Proc. Zool. Soc._ 1878.)] + +_Coleüra._[616]—Incisors ¹⁄₃. Extremity of the muzzle broad, forehead +concave. Has two species from East Africa and the Seychelles Islands. + +_Rhynchonycteris._[617]—This genus is distinguished from _Coleüra_ by the +much-produced extremity of the muzzle. The single species, _R. naso_, +from Central and South America, is very common in the vicinity of streams +throughout the tropical parts of these countries; it is usually found +during the day resting on the vertical faces of rocks, or on the trunks +of trees growing over the water, and, owing to the peculiar grayish +colour of the fur covering the body and growing in small tufts from +the antebrachial membrane, so as to counterfeit the weathered surfaces +of rocks and the bark of trees, easily escapes notice. As the shades +of evening approach it appears early on the wing, flying close to the +surface of the water, and seizing the minute insects that hover over it. + +_Saccopteryx._[618]—Incisors ¹⁄₃. Antebrachial membrane with a pouch +opening on its upper surface. This genus contains six species from +Central and South America. In the adult males a valvular longitudinal +opening is found on the upper surface of the membrane, varying in +position in different species. This opening leads into a small pouch (in +some species large enough to hold a pea), the interior of which is lined +with a glandular membrane secreting an unctuous substance of a reddish +colour with a strong ammoniacal odour. The presence of this sac only in +males indicates that it is a secondary sexual character analogous to the +shoulder-pouches of _Epomophorus_ and the frontal sacs of _Hipposiderus_. +It is quite rudimentary in the females. + +_Taphozous._[619]—Incisors ¹⁄₂; upper pair deciduous. This genus, +represented by some ten species, inhabiting the tropical and subtropical +parts of all the eastern hemisphere except Polynesia, forms the +second group of this division, distinguished by the cartilaginous +premaxillaries, deciduous upper incisors, and the presence of only +two lower incisors. Most of the species have a peculiar glandular sac +(Fig. 313) placed between the angles of the lower jaw. This is a sexual +character, for, while always more developed in males than in females, in +some species, although distinct in the male, it is quite absent in the +female. An open gular sac is wanting in both sexes in _T. melanopogon_, +but about its usual position the openings of small pores may be seen, the +secretion exuding from which probably causes the hairs to grow very long, +forming the black beard found in many male specimens of this species. + +[Illustration: FIG. 313.—Heads of _Taphozous longimanus_, showing +relative development of gular sacs in male and female. (Dobson, _Proc. +Zool. Soc._ 1873.)] + +In the _Diclidurine_ division there is but a single genus, represented by +two species. + +_Diclidurus._[620]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃; total +32. Both species are from the Neotropical region, the typical _D. +albus_ ranging as far north as Central America. This Bat resembles the +species of _Taphozous_ in the form of the head and ears, but, besides +other characters, differs from all other Bats in possessing a peculiar +pouch, opening on the centre of the inferior surface of the interfemoral +membrane; the extremity of the tail enters this, and perforates its +fundus. + +The _Noctilionine_ division is likewise represented only by a single +genus, with two species. This genus connects the present with the +following family, possessing characters common to both, but also so many +remarkable special peculiarities as almost to warrant the formation of a +separate family for its reception. + +_Noctilio._[621]—Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total +28. The two species _N. leporinus_ and _N. albiventer_ inhabit Central +and South America. The typical _N. leporinus_ is a Bat of very curious +aspect, with strangely folded lips, erect cutaneous processes on the +chin, and enormous feet and claws. The first upper incisors are close +together, and so large as to conceal the small outer ones, while in the +lower jaw there is one pair of small incisors. This apparent resemblance +to a Rodent actually led Linnæus to remove this species from the Bats and +place it in the Rodents. This Bat is remarkable for feeding on fish—a +circumstance which has only recently been fully authenticated. + +The remaining genus of this subfamily is regarded as representing another +division, which may be known as the _Rhinopomatine_ division. + +_Rhinopoma._[622]—This genus, represented by the single species _R. +microphyllum_, might also be elevated to the rank of a family, for it is +difficult to determine its exact affinities, a kind of cross relationship +attaching it to the _Nycteridæ_ on the one hand and to this family, +in which it is here placed provisionally, on the other. This species, +distinguished from all other Microchiroptera as well by the presence of +two phalanges in the index finger as by its remarkably long and slender +tail projecting far beyond the narrow interfemoral membrane, inhabits +the subterranean tombs in Egypt and deserted buildings generally from +North-East Africa to Burma. + +[Illustration: FIG. 314.—Skull of _Rhinopoma microphyllum_. × 2. (Dobson, +_Monogr. Asiat. Chiropt._)] + +Subfamily =Molossinæ=.—Tail thick, produced far beyond the posterior +margin of the interfemoral membrane (except in _Mystacops_); legs short +and strong, with well-developed fibula; upper incisors strong. This +subfamily includes all the species of _Emballonuridæ_ with short and +strong legs and broad feet (whereof the first toe, and in most species +the fifth also, is much thicker than the others, and furnished with long +curved hairs), well-developed callosities at the base of the thumbs, +and a single pair of large upper incisors occupying the centre of the +space between the canines. In all the species the feet are free from the +wing-membrane, which folds up perfectly under the forearm and legs; the +interfemoral membrane is retractile, being movable backwards and forwards +along the tail, and this power of varying its superficial extent must +confer upon these Bats great dexterity in quickly changing the direction +of their flight, as when obliged to double in pursuing their swift +insect prey, which their extremely expansible lips evidently enable them +to secure with ease. Like the preceding subfamily, the genera may be +arranged in divisions, of which there are two. + +The _Molossine_ division is characterised by the production of the tail +beyond the posterior margin of the interfemoral membrane; it includes +three genera. + +_Chiromeles._[623]—Dentition: _i_ ¹⁄₁, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total +26. Hallux much larger than the other toes and separable from them, ears +separate. This genus is represented by a single species, _C. torquatus_, +of large size (forearm 3·1 inches) and peculiar aspect, inhabiting the +Indo-Malayan sub-region. This Bat is nearly naked, a collar only of +thinly spread hairs half surrounding the neck; and is further remarkable +for its enormous throat-sac and curious nursing-pouches. The former +consists of a great semicircular fold of skin forming a deep pouch round +the neck beneath, and concealing the orifices of large subcutaneous +pectoral glands, which discharge an oily fluid of insufferably offensive +smell. The nursing-pouch is formed on each side by an extension of a fold +of skin from the side of the body to the inferior surfaces of the humerus +and femur. In the anterior part of this pouch the mammæ are placed. + +_Molossus._[624]—Dentition: _i_ ¹⁄₁₋₂, _c_ ¹⁄₁, _p_ ¹⁻²⁄₁, _m_ ³⁄₃; +total 24 or 28. Upper incisors close together in the middle line. +There are some ten species, restricted to the tropical and subtropical +regions of the New World. The woodcut of the head of _M. glaucinus_ +(Fig. 315) exhibits the general physiognomy of the Bats of this genus. +_M. obscurus_, a small species, is very common in tropical America. It +inhabits the hollow trunks of palms and other trees, and also the roofs +of houses. The males and females live apart (as, indeed, appears to be +the case in most, if not in all, species of Bats). In the hollow trunk +of a palm two colonies were discovered, one consisting of from 150 to +200 individuals, exclusively males, while the other was composed almost +entirely of females. + +[Illustration: FIG. 315.—Head of _Molossus glaucinus_. (Dobson, _Proc. +Zool. Soc._ 1876.)] + +_Nyctinomus._[625]—Dentition: _i_ ¹⁄₃₋₂, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂, _m_ ³⁄₃; +total 32 or 28. Upper incisors separated in the middle line. The +genus contains about twenty-five species, inhabiting the tropical and +subtropical parts of both hemispheres. The lips of the Bats of this genus +are even more expansible than in _Molossus_, in many of the species (as +in the woodcut of the head of _N. macrotis_, Fig. 316) showing vertical +wrinkles. _N. tæniotis_, one of the largest species, alone extends into +Europe, and has been taken as far north as Switzerland. _N. johorensis_, +from the Malay Peninsula, is remarkable from the extraordinary form of +its ears. _N. brasiliensis_ is nearly as common as _Molossus obscurus_ +in tropical America, and extends farther north (California) and south +than that species. + +In the _Mystacopine_ division the tail perforates the interfemoral +membrane and appears upon the upper surface. + +[Illustration: FIG. 316.—Head of _Nyctinomus macrotis_. (Dobson, _Proc. +Zool. Soc._ 1876.)] + +_Mystacops._[626]—This genus includes only _M. tuberculatus_ of New +Zealand, where, together with _Chalinolobus tumorio_, it represents the +whole indigenous mammalian fauna of the islands. There are three distinct +phalanges in the middle finger; the greater part of the wing-membrane is +exceedingly thin, but a narrow portion along the forearm, the sides of +the body, and the legs is remarkably thick and leathery; beneath this +thickened portion the wings are folded. With the wings thus encased, this +species is the most quadrupedal of Bats. Other peculiarities of structure +are found in the remarkable form of the claws of the thumbs and toes, +which have each a small talon projecting from its concave surface near +the base, also in the sole of the foot and inferior surface of the leg, +as shown in Fig. 317. The plantar surface, including the toes, is covered +with soft and very lax integument deeply wrinkled, and each toe is marked +by a central longitudinal groove with short grooves at right angles to +it. The lax wrinkled integument is continued along the inferior flattened +surface of the ankle and leg. These peculiarities appear to be related to +climbing habits in the species. + +[Illustration: FIG. 317.—Pollex and leg and foot of _Mystacops +tuberculatus_, enlarged. (Dobson, _Proc. Zool. Soc._ 1876.)] + +_Fossil Emballonuridæ._—In the cavern-deposits of Madras remains of +the existing _Taphozous saccolæmus_ are not uncommon; while in the +corresponding beds of Brazil bones of a _Molossus_, probably referable +to _M. temmincki_, now inhabiting the same region, are met with. It has +been suggested that remains from the Upper Eocene Phosphorites of Central +France may indicate the existence of the genus _Taphozous_ at that early +epoch. + + +_Family_ PHYLLOSTOMATIDÆ. + +Middle finger with three well-developed bony phalanges; first phalanx +of the middle finger short; nostrils in the front part of the cutaneous +nasal appendages, or opening by simple apertures at the extremity of +the muzzle; chin with warts or erect cutaneous ridges; premaxillæ well +developed, united in front. + +The members of this family are readily distinguished by the third phalanx +in the middle finger, associated either with distinct cutaneous nasal +appendages, or with well-developed first upper incisors, or with both. +Unlike the _Rhinolophidæ_, their eyes are generally large; and the tragus +is well developed, maintaining almost the same form throughout the +species, however much the other parts of the body may vary. The fur is of +a dull colour, and the face and back (in the _Stenodermatine_ division +especially) are often marked with white streaks, as in the _Pteropodidæ_, +of which these Bats take the place in the western hemisphere. A few +species, probably all those with the tail and interfemoral membrane well +developed, feed principally on insects, while the greater number of the +species of the _Vampirine_ and _Glossophagine_ divisions appear to live +on a mixed diet of insects and fruits; and the _Desmodontine_ division, +of which two species only are known, are true blood-suckers, and have +their teeth and intestinal tract specially modified in accordance with +their habits. The family is restricted to the tropical and subtropical +parts of Central and South America. + +Subfamily =Chilonycteriinæ=.—Nostrils opening by simple apertures at the +extremity of the muzzle in front, not margined by a distinct nose-leaf; +chin with expanded leaf-like appendages. It includes two genera. + +[Illustration: FIG. 318.—Head of _Mormops blainvillei_. (Dobson, _Cat. +Chiropt. Brit. Mus._)] + +_Chilonycteris._[627]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; +total 34. The crown of the head is moderately elevated above the facial +line, and the basicranial axis is almost in the same plane as the facial. +There are about half a dozen species. + +_Mormops._[628]—The two species of this genus are distinguished from +_Chilonycteris_ by the great elevation of the crown of the head above +the line of the face, as well as by the basicranial plane being nearly +at right angles to the facial. Both species are noticeable for their +peculiar physiognomy, as is shown in the accompanying woodcut (Fig. 318). + +Subfamily =Phyllostomatinæ=.—Nostrils opening on the upper surface of +the muzzle, the nasal apertures more or less surrounded or margined by +well-developed cutaneous appendages, forming a distinct nose-leaf; chin +with warts. The numerous genera, most of which can only be mentioned here +by name, may be arranged under four divisions. + +In the first or _Vampirine_ division the muzzle is long and narrow in +front; the distance between the eyes is generally less than, rarely equal +to, that from the eye to the extremity of the muzzle; the nose-leaf +is well developed, horse-shoe shaped in front, and lanceolate behind; +interfemoral membrane well developed; tail generally distinct, rarely +absent; inner margin of the lips not fringed. The dentition is: _i_ +²⁄₂₋₁, _c_ ¹⁄₁, _p_ ²⁄₂₋₃, _m_ ³⁄₃; total 32. The cusps of the upper +molars are usually well developed, and arranged in a W. Nearly all the +species of this division appear to be insectivorous, so that the name +applied to them must not be considered as having any relation to their +habits. _Vampyrus spectrum_, a large Bat inhabiting Brazil, of forbidding +aspect, which was long considered by naturalists to be sanguivorous +in its habits, and named accordingly by Geoffroy, has been shown by +the observations of modern travellers to be mainly frugivorous, and is +considered by the inhabitants of the countries in which it is found to +be perfectly harmless. It is the largest Bat in America, the length of +the forearm being 4·2 inches. _Otopterus waterhousei_ appears to prey +occasionally on small species of Bats, like _Megaderma lyra_ of the +eastern hemisphere, which it resembles in many respects. + +_Lonchorhina_,[629] _Otopterus_,[630] _and Dolichophyllum_.[631]—These +three genera are characterised by the tail continuing to the hinder +margin of the interfemoral membrane. _Lonchorhina_ is represented by the +single species _L. aurita_, in which the nose-leaf is much elongated, and +the ear-conch and tragus are unusually large. + +_Vampyrus_,[632] _etc._—In all the remaining genera of this division the +tail perforates the interfemoral membrane, so as to appear upon its upper +surface. These genera are _Vampyrus_, _Lophostoma_, _Micronycteris_,[633] +_Trachyops_, _Phylloderma_, _Phyllostoma_, _Anthorhina_,[634] _Mimon_, +_Hemiderma_[635] and _Rhinophylla_; all, with the exception of the last, +being distinguished from one another chiefly by the form of the skull +and the presence or absence of the second lower premolar. _Trachyops_, +_Phylloderma_, and the three last-named genera are each represented by a +single species. _Phyllostoma hastatum_, in which the forearm has a length +of 3·2 inches, and next in point of size to _Vampyrus spectrum_, is a +well-known species in South America; _P. elongatum_ (Fig. 319) differs +in its smaller size and much larger nose-leaf. _Hemiderma brevicauda_ +is a small species, which forms a connecting link between this and the +next division. _Rhinophylla pumilio_, the smallest known species of the +family, is further distinguished by the narrowness of its molars, which +do not form W-shaped cusps, and by the very small size of the last upper +molar; characters connecting it with the _Stenodermatine_ division. + +[Illustration: FIG. 319.—Head of _Phyllostoma elongatum_. (From Dobson, +_Proc. Zool. Soc._ 1866.)] + +In the second or _Glossophagine_ division of the subfamily the muzzle +is long and narrow; the tongue remarkably long and extensible, much +attenuated towards the tip, and beset with very long filiform recurved +papillæ; lower lip with a wide groove above, and in front margined by +small warts; nose-leaf small; tail short or absent. Dentition: _i_ ¹⁄₁, +_c_ ²⁄₂, _p_ ²⁻³⁄₃₋₂, _m_ ²⁄₃₋₂; teeth very narrow; molars with narrow +W-shaped cusps, sometimes indistinct or absent; lower incisors very small +or deciduous. + +The ten species included in this division are arranged under seven +genera,[636] distinguished principally by differences in the form and +number of the teeth and the presence or absence of the zygomatic arch. +The form and position of the upper incisors are extremely variable. +In _Glossophaga_ and _Phyllonycteris_ the upper incisors form, as in +the _Vampyrine_ division, a continuous row between the canines; in +_Monophylla_ and _Leptonycteris_[637] they are separated into pairs by +a narrow interval in front; while in _Lonchoglossa_, _Glossonycteris_, +and _Chœronycteris_ they are widely separated and placed in pairs near +the canines. In the first four genera the lower incisors are present (at +least up to a certain age), while in the last three they are deciduous +even in youth. The zygomatic arch is wanting in _Phyllonycteris_, +_Glossonycteris_, and _Chœronycteris_. + +The typical species is _Glossophaga soricina_, which so closely resembles +_Hemiderma brevicauda_, both in external form and dentition, that it has +frequently been confounded with it. Its long fimbriated tongue, which +it possesses in common with other species of the division, led Spix to +describe it as a blood-sucker, believing that this organ was used to +increase the flow of blood. This view is, however, without foundation, +and from later observations it is evident that the peculiarly shaped +tongue is used by the animal to lick out the pulpy contents of fruits +having hard rinds. The food of the species of this division appears to +consist of both fruit and insects, and the long tongue may also be used +for extracting the latter from the deep corollæ of certain flowers. This +type of tongue is shown in the woodcut of the head of _Chœronycteris_ +(Fig. 320); and it is paralleled among the Megachiroptera by the +Carponycteriine _Pteropodidæ_. + +[Illustration: FIG. 320.—Head of _Chœronycteris mexicana_, showing +fimbriated tongue. (Dobson, _Cat. Chiropt. Brit. Mus._)] + +The _Stenodermatine_ division is characterised by the muzzle being very +short and generally broad in front, the distance between the eyes nearly +always exceeding (rarely equal to) that from the eye to the extremity +of the muzzle; nose-leaf short, horse-shoe shaped in front, lanceolate +behind (except in _Brachyphylla_ and _Centurio_); interfemoral membrane +always concave behind; tail none; inner margin of the lips fringed +with conical papillæ. Dentition: _i_ ²⁄₂₋₁, _p_ ²⁄₂, _m_ ³⁻²⁄₃₋₂; the +number of the molars being either ³⁄₃, ²⁄₃, or ²⁄₂ in different species; +premolars and molars very broad (except in _Sturnira_), the latter with +concave or flat crowns margined externally by raised cutting-edges. +Although the members of this division are usually distinguished from +those of the Vampirine division by the peculiar shortness and breadth of +the muzzle and the form of the molars, yet certain species of the latter +closely resemble those of the former in external appearance, agreeing +almost absolutely in the form of the nose-leaf, of the ears and tragus, +and of the warts on the chin. These resemblances indicate that, while +the form of the teeth and jaws has become modified to suit the nature of +the food, the external characters, being but slightly affected by this +cause, have remained much the same. The food of these Bats appears to +be wholly or in great part fruit. The twenty species have been grouped +into nine genera, distinguished by the form of the skull and teeth. +_Artibeus_, with six species, includes the well-known frugivorous Bat, +_A. perspicillatus_. Waterton believed that _A. planirostris_, a common +Bat in British Guiana, usually found in the roofs of houses, and now +known to be frugivorous, was the true blood-sucking Vampire. _Stenoderma +achradophilum_, found in Jamaica and Cuba, associated with _Artibeus +perspicillatus_, from which it is scarcely distinguishable externally +except by its much smaller size, differs altogether in the absence of +the horizontal plate of the palatal bones. _Sturnira lilium_, while +agreeing with the above in the form of the nose-leaf and ears, differs +from all the species of the family in its longitudinally-grooved molars, +which resemble those of the _Pteropodidæ_ more closely than those of +any other Bats; and the presence of tufts of long differently coloured +hairs over glands in the sides of the neck shows another common character +still more remarkable, which can scarcely be considered the result of +adaptive change. _Centurio senex_ is the type of a genus distinguished +from _Stenoderma_ and other genera of this division by the absence +of a distinct nose-leaf; its facial aspect, as shown in Fig. 321, is +altogether bizarre. + +[Illustration: FIG. 321.—Head of _Centurio senex_. (Dobson, _Cat. +Chiropt. Brit. Mus._)] + +In the last or _Desmodont_ division the muzzle is conical and short; +there is a distinct nose-leaf; the interfemoral membrane is very +short; and the tail is wanting. Dentition: _i_ ¹⁄₂, _c_ ¹⁄₁, _p_ ²⁄₃, +_m_ ¹⁻⁰⁄₁₋₀; total 24 or 20. Upper incisors very large, trenchant, +occupying the whole space between the canines; premolars very narrow, +with sharp-edged longitudinal crowns; molars rudimentary or wanting; +stomach greatly elongated, intestiniform. There are only two genera, the +single species of each of which are the true blood-sucking Vampires. +They appear to be confined chiefly to the forest-clad parts, and their +attacks on men and other warm-blooded animals were noticed by some of +the earliest writers. Thus Peter Martyr (Anghiera), who wrote soon after +the conquest of South America, says that in the Isthmus of Darien there +were Bats which sucked the blood of men and cattle when asleep to such a +degree as to kill them. Condamine, a writer of the eighteenth century, +remarks that at Borja (Ecuador) and in other places they had entirely +destroyed the cattle introduced by the missionaries. Sir Schomburgk +relates that at Wicki, on the river Berbice, no fowls could be kept on +account of the ravages of these creatures, which attacked their combs, +causing them to appear white from loss of blood. Although these Bats +were known thus early to Europeans, the species to which they belonged +were not determined until about sixty years ago, several of the large +frugivorous species having been wrongly set down as blood-suckers and +named accordingly; and it fell to the lot of Darwin to determine at least +one of the blood-sucking species, the following being his account of the +circumstances under which the discovery of the sanguivorous habits of +_Desmodus rufus_ was made: “The Vampire Bat is often the cause of much +trouble by biting the horses on their withers. The injury is generally +not so much owing to the loss of blood as to the inflammation which +the pressure of the saddle afterwards produces. The whole circumstance +has lately been doubted in England; I was therefore fortunate in +being present when one was actually caught on a horse’s back. We were +bivouacking late one evening near Coquimbo, in Chili, when my servant, +noticing that one of the horses was very restive, went to see what was +the matter, and, fancying he could detect something, suddenly put his +hand on the beast’s withers and secured the Vampire.” + +These Bats present, in the extraordinary differentiation of the +manducatory and digestive apparatus, a departure from the type of +other members of the family unparalleled in any of the other orders of +Mammalia, standing apart from all other mammals as being fitted only +for a diet of blood, and capable of sustaining life upon that alone. +Travellers describe the wounds inflicted by the large sharp-edged +incisors as similar to those caused by a razor when shaving: a portion of +the skin being shaved off and a large number of severed capillary vessels +thus exposed, from which a constant flow of blood is maintained. From +this source the blood is drawn through the exceedingly narrow gullet—too +narrow for anything solid to pass—into the intestine-like stomach, whence +it is probably gradually drawn off during the slow process of digestion, +while the animal, sated with food, is hanging in a state of torpidity +from the roof of a cave or the inner side of a hollow tree. + +[Illustration: FIG. 322.—Head of Vampire Bat (_Desmodus rufus_).] + +_Desmodus._[638]—No true molar, and no calcar. The Common Vampire (_D. +rufus_) is widely spread over the tropical and subtropical parts of +Central and South America from Oaxaca to Southern Brazil and Chili. It is +a comparatively small species, a little larger than the common Noctule, +the head and body being about 3 inches in length, the forearm 2½, with a +remarkably long and strong thumb; it is destitute of a tail, and has a +peculiar physiognomy, well represented in Fig. 322. The body is covered +with rather short fur of a reddish-brown colour, but varying in shade; +the extremities of the hairs being sometimes ashy. The teeth are peculiar +and admirably adapted for the purposes for which they are employed. The +upper incisor is greatly enlarged, and of somewhat triangular shape (Fig. +323); the canine, although smaller than the incisor, is large and sharp; +but the cheek-teeth are very small, with laterally compressed crowns +rising but slightly above the level of the gum, their longitudinally +disposed cutting-edges being continuous with the base of the canine and +with each other. The lower incisors are small, bifid, and separated from +the canine, with a space in front. The lower cheek-teeth are narrow, like +those in the upper jaw, but the anterior tooth is slightly larger than +the others, and separated by a small space from the canine. Behind the +lower incisors the jaw is deeply hollowed out to receive the extremities +of the large upper incisors. The exceedingly narrow œsophagus opens at +right angles into the slender, intestine-like stomach, which almost +immediately terminates on the right, without a distinct pylorus, in the +duodenum, but on the left forms a greatly elongated fundus, bent and +folded upon itself, appearing at first sight like part of the intestines. +This cardiac extremity of the stomach is, for a short distance, to the +left of the entrance of the œsophagus, still very narrow, but soon +increases in size, till near its termination it attains a diameter quite +three times that of the short pyloric portion. The length of this cardiac +diverticulum of the stomach appears to vary from 2 to 6 inches, the size +in each specimen probably depending on the amount of food obtained by the +animal before it was captured. + +[Illustration: FIG. 323.—Dentition of _Desmodus rufus_. _a_, Front view +of upper teeth; _b_, left lateral view of upper and lower teeth.] + +_Diphylla._[639]—A small true molar in each jaw, and a rudimentary +calcar. The single species _D. ecaudata_ inhabits Brazil, and appears to +be much less abundant than _Desmodus rufus_, from which, in addition to +the characters already mentioned, it is distinguished by its slightly +smaller size, the absence of a groove in the front of the lower lip, +the non-development of the interfemoral membrane in the centre, and the +peculiar form of the lower incisors, which are much expanded in the +direction of the jaws and pectinated, forming a semicircular row touching +each other, the outer pair being wider than the inner ones, and having +six notches, the inner pair having only three notches. + +_Fossil Phyllostomatidæ._—Remains of _Vampyrus spectrum_, as well as of +several species of _Phyllostoma_ or closely allied types, are found in +the cavern deposits of Brazil. The mandible of a large Bat from the Upper +Eocene Phosphorites of Central France, described as _Necromantis_, has +been referred to this family—a determination which, if confirmed, will be +of great interest from a distributional point of view. + + _Bibliography of Chiroptera._—G. E. Dobson, _Catalogue of the + Chiroptera in the Collection of the British Museum_, 1878, + including descriptions of all the species of Bats then known; + subsequent papers by the same author in _Rep. Brit. Assoc._, + _Proc. Zool. Soc._, _Ann. Mag. Nat. Hist._, and _Bull. Soc. + Zool. de France_; by Peters in _Monatsb. Akad. Wiss. Berlin_; + by O. Thomas in _Ann. Mag. Nat. Hist._, _Proc. Zool. Soc._, + and _Ann. Mus. Genova_; and by J. Scully in _Ann. Mag. Nat. + Hist._ and _Journ. As. Soc. Bengal_; H. A. Robin, _Recherches + Anatomiques sur les Mammifères de l’Ordre des Chiroptères_, + Paris, 1881; W. T. Blanford, “Notes on Indian Chiroptera,” + _Journ. As. Soc. Bengal_, vol. lviii. (1888). See also papers + by Jentink, Bocage, and others. + + + + +CHAPTER XIV + +THE ORDER PRIMATES + + +This order in the system of Linnæus includes Man, the Monkeys, the +Lemurs, and the Bats. By common consent of all zoologists the last-named +animals have been removed into a distinct order; but with regard to the +association of the others there has been, and still is, much difference +of opinion. + +That all the Monkeys, from the highest Anthropoid Apes to the lowest +Marmosets, form a natural and tolerably homogeneous group seems never +to have been questioned; but whether the Lemurs on the one hand and Man +on the other should be united with them in the same order are points of +controversy. If, in accordance with the traditional views of zoologists, +the former are still considered to be members of this order, they must +form a suborder apart from all the others, with which they have really +very little in common except the opposable hallux of the hind foot, a +character also met with in the Opossums, and which is therefore of very +secondary importance.[640] + +Using the term Primates in this wider sense it is not easy to give +any precise definition of the order. The dentition is diphyodont and +heterodont; the number of incisors being very generally ²⁄₂, and that +of the molars, with the exception of the _Hapalidæ_, being ³⁄₃. The +cheek-teeth are adapted for grinding, the molars being more complex than +the premolars, and usually having four main tubercles, which may be +either subconical or more or less compressed. The orbit is invariably +surrounded by a ring of bone; the clavicles are well developed; and the +radius and ulna are never united. The scaphoid and lunar of the carpus, +and commonly also the centrale, remain distinct from one another. There +are usually five digits furnished with well-developed nails in both +the manus and the pes; but the pollex may be rudimentary or wanting. +The hallux, except in Man, is opposable to the other digits, and has a +flat nail (absent in _Simia_); and the pollex, when present, is usually +also more or less opposable. The terminal phalanges of the digits are +flattened (except in the second digit of the pes of the Lemuroidea), and +not cleft at their extremities. The fingers and toes generally do not +taper towards their extremities, but (except in _Chiromys_) are dilated, +flattened, and rounded at their tips. The humerus has no entepicondylar +foramen, nor the femur a third trochanter. In the alimentary canal +(Fig. 324) the stomach is generally simple, although sacculated in the +subfamily _Semnopithecinæ_ of the _Cercopithecidæ_; and there is always +a cæcum, which is generally of large size. The placenta may be either +non-deciduous, or discoidal and deciduous. There are always two mammæ in +the pectoral region, except in _Chiromys_; and the testes descend into a +scrotum. + +[Illustration: FIG. 324.—Alimentary canal of _Galago_, the greater part +of the small intestine being omitted. _d_, duodenum; _i_, ileum; _cm_, +cæcum; _r_, rectum.] + +The Lemuroidea are decidedly low in the scale of organisation, their +placentation being of a lower type than that of the Insectivora; and all +the Primates retain generalised features in their pentadactylate limbs +and more or less bunodont cheek-teeth. In respect to cerebral characters +and other features the higher representatives of the order have, however, +acquired a specialisation clearly indicating their right to occupy +the highest position in the animal kingdom. So far as the available +material admits of forming an opinion, fossil forms appear to indicate +an intimate connection between the Lemuroidea and Insectivora, so that +in some cases it is almost impossible to determine whether an extinct +type should be referred to the former or to the latter group. It is +noteworthy that while in all existing Primates the upper molars are of +a quadrituberculate type, in the extinct Lemuroid genus _Anaptomorphus_ +they are trituberculate. + + +_Suborder_ LEMUROIDEA. + +The Latin term _Lemur_ was applied by Linnæus to the typical +representatives of the present group of Primates, having been suggested +by the nocturnal habits and strange ghost-like appearance of some of +its members. As these animals had previously no vernacular appellation +in English, this name has been generally adopted, and is now completely +anglicised, making “Lemurs” in the plural. The French call them _Makis_, +and the Germans _Halbaffen_, in allusion to their forming a transition +from monkeys to ordinary quadrupeds. For the same reason they are called +_Prosimiæ_ by some systematic writers. When the name was bestowed by +Linnæus only five species were known, of which one, _L. volans_, Linn. +(_Galeopithecus volans_ of modern writers), is now removed by common +consent from the group. Notwithstanding the discovery of many new and +curious forms, the Lemurs remain a very natural and circumscribed +division of the animal kingdom, though no longer considered a single +genus, but divided up into many genera and even families. + +The existing species are not numerous, and do not diverge widely in their +organisation or habits, being all of small or moderate size, all adapted +to an arboreal life, climbing with ease, and, as they find their living, +which consists of fruits, leaves, birds’ eggs, small birds, reptiles, and +insects, among the branches of the trees, they rarely have occasion to +descend to the ground. None are aquatic, and none burrow in the earth. +Many of the species, although by no means all, are nocturnal in their +habits, spending the day in sleeping in holes, or rolled up in a ball, +perched on a horizontal branch, or in the fork of a tree, and seeking +their food by night. Their geographical distribution is very peculiar; by +far the larger proportion of species, including all those to which the +term “Lemur” is now especially restricted, being exclusively inhabitants +of Madagascar, where they are so abundant and widely distributed that +it is said by M. Grandidier, who has contributed more than any other +traveller to enrich our knowledge of the structure and manners of these +animals, that there is not a little wood in the whole island in which +some of them cannot be found. From Madagascar as a centre a few species +less typical in character extend through the African continent westward +as far as Senegambia, and others are found in the Oriental region as far +east as the Philippine Islands and Celebes. + +The following are the essential characters by which the suborder as a +whole is distinguished from the Anthropoidea. Skull with the orbit +opening freely into the temporal fossa beneath the postorbital bar +(except in _Tarsius_); and the lachrymal foramen situated externally to +the margin of the orbit (Fig. 327). The pollex and hallux are always +well developed, the latter being especially large; the second or index +digit of the manus may be rudimentary; while in the pes the second digit +invariably terminates in a long pointed claw. The cerebral hemispheres do +not completely overlap the cerebellum, and are but slightly convoluted. +The uterus is bicornuate. The placenta is non-deciduate, and either +diffused or bell shaped—the whole of the chorion except the cephalic +pole being covered with villi; and the allantois is of very great size. +There may be abdominal mammæ. Except in _Chiromys_, the first pair of +upper incisors are separated in the middle line. In marked contrast to +the Anthropoidea, the middle or transverse portion of the colon is almost +always folded or convoluted on itself. (See Fig. 324.) + +In subdividing the group for the purpose of a more detailed description +of the different animals of which it is composed it must first be noted +that there are two very aberrant forms, each represented by a single +species—the little _Tarsius_ of the Indian archipelago, and the singular +_Chiromys_ or Aye-aye, which, though an inhabitant of Madagascar, the +headquarters of the suborder, and living in the same forests and under +the same external conditions as the most typical Lemurs, exhibits a most +remarkable specialisation in the structure of its limbs and teeth, the +latter being modified so as to resemble, at least superficially, those of +the Rodents, in which order it was once placed. The differences between +these two forms and the remaining Lemurs are so great that the whole +suborder naturally divides itself into three families, the first of which +may be again divided into four subfamilies. + + +_Family_ LEMURIDÆ. + +Upper incisors two on each side, small and separated by an interval in +the middle line. Upper canine large, conical, compressed, and pointed. +Premolars two or three, molars three on each side above and below, with +numerous more or less pointed cusps. In the front of the lower jaw are +on each side two or three closely approximated, long, slender teeth +lying almost horizontally and projecting forwards. These are generally +considered to represent the incisors and canine, but there is some doubt +about their homologies, and they may be all considered as incisors, the +canine being absent. The first lower premolar larger than those behind +it, and shaped like a canine, of which it performs the function (Fig. +327). The orbit and temporal fossa widely continuous beneath the bar +of bone (formed by the frontal and jugal) constituting the posterior +boundary of the former cavity. The fibula well developed and distinct +from the tibia. All the digits of both feet (except the second of the +hind foot) with flat nails, and corresponding form of ungual phalanges. + +Subfamily =Indrisinæ=.—The dentition of the adult consists of thirty +teeth, usually expressed by the formula _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ +³⁄₃; but, as indicated above, they may be _i_ ²⁄₂, _c_ ¹⁄₀, _p_ ²⁄₂, _m_ +³⁄₃. In the milk-dentition there are twenty-two teeth, the true molars +of course not being represented, but there are two additional teeth in +the fore part of the lower jaw which have no successors in the permanent +series. Hind limbs greatly developed, but the tarsus normal. Hallux of +large size, and very opposable. The other toes united at their base by a +fold of skin, which extends as far as the end of the first phalanx. Mammæ +two, pectoral. Cæcum very large, and colon extremely long and spirally +coiled. + +The animals of this group are, as their organisation indicates, +essentially arboreal, and feed exclusively on fruit, leaves, buds, and +flowers. They are restricted geographically to the island of Madagascar. +Among them are the largest members of the suborder. A detailed and +beautifully illustrated account of their characters, external and +internal, and distribution and habits, is given in the _Histoire +Naturelle de Madagascar_, by A. Grandidier and Alphonse Milne-Edwards +(1875). The species are not numerous and are distributed into three +genera. + +_Indris._[641]—Upper incisors subequal in size. Upper canine larger than +the first premolar. Muzzle moderately long. Ears exserted. Carpus without +an os centrale. Tail rudimentary. Vertebræ: C 7, D 12, L 9, S 4, C 9. + +The only well-established species is the Indris (_I. brevicaudata_, Fig. +325), discovered by Sonnerat in 1780. It is the largest of the Lemurs, +the length of the head and body being about 2 feet, and the tail 2 +inches. It is very variable in colour, for although usually nearly black, +marked with whitish spots principally in the lumbar region and forearm, +individuals have been found quite white. It inhabits exclusively the +forests of a part of the east coast of Madagascar, living in small troops +of four or five in number, and resembling in most of its habits the +animals of the next genus. + +_Propithecus._[642]—Second upper incisor much smaller than the first. +Upper canine larger than the first premolar. Muzzle rather short. Ears +short, concealed by the fur. An os centrale in the carpus. Tail long. +Vertebræ: C 7, D 12, L 8, S 3, C 28. + +[Illustration: FIG. 325.—Indris (_Indris brevicaudata_). From +Milne-Edwards and Grandidier, _Mammifères de Madagascar_, pl. 12.] + +The species are all subject to great variations in colour, which has +led to much difficulty in discriminating them, and to much confusion of +synonymy. Grandidier and Milne-Edwards recognise three as certainly +distinct—_P. diadema_, _P. verreauxii_, and _P. coronatus_ (Fig. 326). +Some of these are to be found in almost every part of the island of +Madagascar, living in the woods in small bands of six or eight together, +and feeding exclusively on buds, flowers, and berries. Their powerful +hind limbs enable them to leap from tree to tree, often to a distance of +10 yards, without any apparent effort, and thus seeming to fly through +the air. When obliged to descend to the ground to pass from one clump +of trees to another they do not run on all fours, but stand erect, and +throwing their arms above their heads progress by a series of short +jumps, producing an effect which is described by travellers who have +seen them thus in their native haunts as exceedingly ludicrous. They are +not nocturnal, but most active in the morning and evening, remaining +seated or coiled up among the branches during the heat of the day. They +are naturally of a quiet and gentle disposition, and do not show much +intelligence. All the species are also less vociferous than the true +Lemurs, only when alarmed or angered making a noise which has been +compared to the clucking of a fowl. Like the rest of the subfamily they +never have more than a single young one at a time. + +[Illustration: FIG. 326.—_Propithecus coronatus._ (From Milne-Edwards and +Grandidier, _Mammifères de Madagascar_, pl. 7.)] + +_Avahis._[643]—Second upper incisor larger than the first. Upper canine +scarcely larger than the first premolar. Muzzle very short. Ears very +small and hidden in the fur, which is very soft and woolly. Carpus +without an os centrale. Tail long. Vertebræ: C 7, D 11, L 9, S 3, C 23. + +One species, _A. laniger_, the Woolly Lemur, or Avahis, considerably +smaller than any of the last genus. It differs from them in its habits, +being quite nocturnal, and not associating in small troops, but being +always met with either alone or in pairs. It is very slow in its +movements, and rarely descends to the ground, but when it does it walks +upright like the other _Indrisinæ_. It is found throughout the forests +which clothe the mountains on the east coast of Madagascar, and also in a +limited district on the north-west coast, the specimens from the latter +locality being of smaller size and rather different in colour. + +Subfamily =Lemurinæ=.—The dentition in the adult consists of thirty-six +teeth, which, as usually enumerated, are _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ +³⁄₃. In the fore part of the lower jaw are on each side three elongated, +compressed, procumbent teeth, of which the outer, usually considered +the homologue of the canine, is larger than the others. All the forms +have long tails. Hind limbs not of the same disproportionate size as in +the last group; and the cæcum much less developed. Tarsus but slightly +elongated, the calcaneum being always less than one-fourth the length of +the tibia. Toes of the hind feet free to the base. Habitat, Madagascar, +and some of the adjacent Comoro Islands. + +[Illustration: FIG. 327.—Skull of Ring-tailed Lemur (_Lemur catta_). × ⅓; +_uc_, Upper canine; _lc_, lower canine; _pm_, premolars; _m_, molars.] + +This group contains the typical Lemurs, or rather those to which the +term is now chiefly restricted. Two somewhat aberrant members make it +necessary to divide it into three genera. + +_Lemur._[644]—Upper incisors separated by an interval in the middle, and +not in contact with each other or the canine, in front of which they are +both placed. Muzzle elongated. Ears conspicuous and tufted. Mammæ two, +pectoral. Vertebræ: C 7, D 12, L 7 (or D 13, L 6), S 3, C 27. + +[Illustration: FIG. 328.—The Ring-tailed Lemur (_Lemur catta_).] + +Animals much about the size of a common Cat, with Fox-like faces, soft +thick fur, and long tails well clothed with hair. Not having the same +disproportionate size of the limbs as the last group, they are much +more quadrupedal in their actions, walking on the ground or running +along the branches of trees on all four feet, but also jumping with +marvellous agility. They are gregarious, living in small troops, are +diurnal in their habits, but most active towards evening, when they make +the woods resound with their loud cries. They feed not only on fruits +and buds, but also on eggs, young birds, and insects. When at rest or +sleeping they generally coil their long, bushy tails around their bodies, +apparently for the sake of the warmth it affords. They have either one +or two young ones at a birth, which are at first nearly naked, and are +carried about, hanging close to and almost concealed by the hair of the +mother’s belly. After a while they change their position and mount upon +the mother’s back, where they are carried about until they are able to +climb and leap by themselves. Though no member of the _Indrisinæ_ has as +yet lived long enough in captivity to be brought alive to Europe, various +species of _Lemurinæ_ are commonly seen in menageries, and often breed in +England. They present a great tendency to variation in their colouring, +in consequence of which many nominal species have been made. The most +distinct, and at the same time most beautiful, is the Ring-tailed Lemur +(_L. catta_, Fig. 328), of a delicate gray colour, and with a long tail +marked with alternating rings of black and white. This is said by Mr. +G. A. Shaw[645] to be an exception to all the other Lemurs in not being +arboreal, but living chiefly among rocks and bushes. Pollen, however, +says that it inhabits the forests of the south-west parts of Madagascar, +living, like its congeners, in considerable troops, and not differing +from them in its habits. He adds that it is extremely gentle, and active +and graceful in its movements, and utters at intervals a little plaintive +cry like that of a domestic cat. All the others have the tail of uniform +colour. The largest species is _L. varius_, the Ruffed Lemur, sometimes +black and white, and sometimes reddish-brown, the variation apparently +not depending on sex or age, but on the individual. In _L. macaco_ the +male is black and the female red. _L. mongoz_, _L. collaris_, and _L. +albifrons_ are other well-known species. + +_Hapalemur._[646]—Upper incisors very small, subequal, separated widely +in the middle line. Those of either side in contact with each other and +with the canine, the posterior one being placed on the inside, and not in +front of the latter. Muzzle very short and truncated. Mammæ four. There +is apparently but one species, _H. griseus_, smaller than any of the true +Lemurs, of a dark gray colour, with round face and short ears. It is +quite nocturnal, and lives chiefly among bamboos, subsisting on the young +shoots. A second species has been named _H. simus_, but it is doubtful if +it is more than a variety. + +_Lepidolemur._[647]—Upper incisors absent or rudimentary. Muzzle more +elongated than in the last. No distinct os centrale in the carpus. +_L. mustelinus_ is the best-known species. It has, at all events when +adult, no upper incisors. It is rare, and like _Hapalemur_ nocturnal in +its habits. A second closely allied species, but with better developed +premaxillæ, containing a pair of small styliform incisors, has been +described by Peters[648] under the name of _Myxocebus caniceps_. + +Subfamily =Galaginæ=.—Dentition as in _Lemurinæ_, from which the members +of this subfamily are distinguished by the elongation of the tarsus, +caused by a peculiar modification of the calcaneum and the navicular, the +distal portion of the former and the whole of the latter having the form +of almost cylindrical rods placed side by side, while the other bones +retain nearly their normal form and proportion. + +_Chirogaleus._[649]—Last upper premolar very much smaller than the first +molar, with only one external cusp. The animals included under this name +appear to form a transition between the true Lemurs and the Galagos. The +genus was originally established by Geoffroy St. Hilaire in 1812 for +the reception of three species only known at that time by drawings made +in Madagascar by the traveller Commerson. Subsequent discoveries have +brought to light several others that may be referred to it, including +one or two which are sometimes considered as forming a genus apart under +the name of _Microcebus_. They are all small, some being less than a +rat in size, long-tailed, and nocturnal in their habits. One of the +largest, _C. furcifer_, is of a reddish-gray colour, and distinguished +by a dark median stripe on its back which divides on the top of the head +into two branches, one of which passes forwards above each eye. The most +interesting peculiarity of these animals, a knowledge of which we owe +to M. Grandidier, is that certain species (_C. samati_, _C. gliroides_, +_C. milii_, etc.) during the dry season coil themselves up in holes of +trees and pass into a state of torpidity like that of the hibernating +animals in the winter of northern climates. Before this takes place +an immense deposit of fat accumulates upon certain parts of the body, +especially upon the basal portion of the tail, which has then dimensions +corresponding to that of the well-known fat-tailed Sheep of the Cape, but +which by the time they emerge from their torpor has acquired its normal +proportions. The smallest species, to which many names have been given +(_C. pusillus_, _rufus_, _smithi_, etc.), lives among the small branches +on the tops of the highest trees, feeding on fruit and insects, and +making nests which resemble those of birds. + +_Galago._[650]—Last upper premolar with two large external cusps, and +nearly equalling the first molar in size. Calcaneum about one-third the +length of the tibia, and the navicular much longer than the cuboid. +Vertebræ: C 7, D 13, L 6, S 3, C 22-26. Tail long, and generally bushy. +Ears large, rounded, naked, and capable of being folded at the will of +the animal. Mammæ four, two pectoral and two inguinal. + +The Galagos differ from all the Lemuroids previously mentioned, inasmuch +as they are inhabitants, not of Madagascar, but of the African continent, +being widely distributed in the wooded districts from Senegambia in the +west to Abyssinia in the east, and as far south as Natal. They pass the +day in sleep, but are very active at night, feeding on fruit, insects, +and small birds. When they descend to the ground they sit upright, and +move about by jumping with their hind legs, like jerboas and kangaroos. +They are pretty little animals, varying in size from that of a small cat +to less than a rat, with large eyes and ears, soft woolly fur, and long +tails. There are several species, of which _G. crassicaudatus_, from +Mozambique, is the largest. A similar species, or perhaps variety, from +Angola is _G. montieri_. _G. garnetti_, _alleni_, _maholi_, _demidoffi_, +and _senegalensis_ are other recognised species. The last-mentioned was +the first known to science, having been brought from Senegal by Adanson, +and described in 1796 by Geoffroy, who adopted the name _Galago_, by +which it was said to be called by the natives. + +Subfamily =Lorisinæ=.—Dental formula as in _Lemurinæ_. Index finger very +short, sometimes rudimentary and nailless. Fore and hind limbs nearly +equal in length. Tarsus not specially elongated. Pollex and hallux +diverging widely from the other digits, the hallux especially being +habitually directed backwards. Tail short or quite rudimentary. Mammæ +two, pectoral. + +A small group of very peculiar animals, of essentially nocturnal habits, +and remarkable for the slowness of their movements. They are completely +arboreal, their limbs being formed only for climbing and clinging to +branches, not for jumping or running. They have rounded heads, very +large eyes, short ears, and thick, short, soft fur. They feed not only +on vegetable substances, but, like many of the _Lemuridæ_, on insects, +eggs, and also birds, which they steal upon while roosting at night. None +of the species are found in Madagascar. One of the greatest anatomical +peculiarities of these animals is the breaking up of the large arterial +trunks of the limbs into numerous small parallel branches, constituting a +_rete mirabile_, which is found also in the Sloths, with which the Loris +are sometimes confounded on account of the slowness of their movements. +The animals of this group are usually divided into four genera, though +the characters by which they are separated are very trivial. There are +more properly two natural divisions. + +_A._ Characterised by the index finger being small, but having the +complete number of phalanges, and by their Asiatic habitat. + +These form the genus _Loris_ of Geoffroy St. Hilaire (1796), _Stenops_ +of Illiger (1811), but they were in 1812 divided by Geoffroy into two +genera, _Nycticebus_ and _Loris_, a division which has been accepted by +most modern zoologists. + +_Nycticebus._[651]—First upper incisor larger than the second, which is +often early deciduous. Inner margins of the orbits separated from each +other by a narrow flat space. Nasal and premaxillary bones projecting +but very slightly in front of the maxillæ. Body and limbs stout. No +external tail. Vertebræ: C 7, D 17, L 6, S 3, C 12. The species are _N. +tardigradus_, the common Slow Lemur or Loris, of the Malay Countries, +Sumatra, and Borneo; _N. javanicus_, of Java; and _N. cinereus_ (Fig. +329) of Siam and Cochin China. The habits of all are much alike. They +lead a solitary life in the recesses of large forests, chiefly in +mountainous districts, where they sleep during the day in holes or +fissures of large trees, rolled up into a ball, with the head between the +hind legs. On the approach of evening they awake; and during the night +they ramble among the branches of trees, slowly and quietly, in search +of their food, which consists of tender leaves and fruit, small birds, +insects, and mice. When in quest of living prey they move noiselessly +till quite close, and then suddenly seize it with one of their hands. The +female produces but one young one at a time. _L. tardigradus_ was placed +by Linnæus at the head of the list of species of his genus _Lemur_, and +its habits doubtless suggested the generic name which was transferred by +Geoffroy to the less nocturnal and spectre-like Madagascar members of the +group.[652] + +[Illustration: FIG. 329.—The Gray Loris (_Nycticebus cinereus_). From A. +Milne-Edwards, _N. Archives du Muséum_, vol iii. pl 3.] + +_Loris_.[653]—Upper incisors very small and equal. Orbits very large, +and only separated in the middle line above by a thin vertical plate of +bone. Nasals and premaxillæ produced forwards considerably beyond the +anterior limits of the maxillæ, and supporting a pointed nose. Body and +limbs slender. No external tail. Vertebræ: C 7, D 14, L 9, S 3, C 6. +This genus is represented only by the Slender Loris (_L. gracilis_) of +Southern India and Ceylon (Fig. 330). This species is common in some +of the forest regions of Southern India, and may be purchased in the +bazaars at Madras, its eyes being regarded as a remedy by the natives for +ophthalmic diseases. It is a strange-looking creature, about the size +of a squirrel, of a yellowish-brown colour, with large, prominent eyes, +pointed nose, long thin body, long, angularly bent, slender limbs, and no +tail. Its habits, according to Mr. W. T. Blanford,[654] are “very similar +to those of _Nycticebus tardigradus_, except that the Slender Loris is +rather quicker in its movements, though still slow in general. Like its +ally, it is purely nocturnal and arboreal, living upon shoots and young +leaves, insects, birds’ eggs, birds, and lizards. It is said to be very +fond of honey or syrup. It sleeps rolled up in a ball with its head +between its legs, grasping its perch with its arms.” + +[Illustration: FIG. 330.—The Slender Loris (_Loris gracilis_). From +Blanford, _Mammalia of British India_, p. 47.] + +_B._ Index fingers reduced to a mere tubercle without nail. Both the +known species are from West Africa. + +_Perodicticus._[655]—A short tail, about a third of the length of the +trunk. Two or three of the anterior dorsal vertebræ have very long +slender spinous processes which in the living animal project beyond the +general level of the skin, forming distinct conical prominences, covered +only by an exceedingly thin and naked integument. The Potto, _P. potto_, +is one of the oldest known members of the lemuroid group, having been +described in 1705 by Bosman, who met with it in his voyage to Guinea. +It was, however, lost sight of until 1825, when it was rediscovered in +Sierra Leone, and fully described by Bennett in 1830 under the name of +_Perodicticus geoffroyi_. Bennett’s generic name has been retained, but +the specific name bestowed by Gmelin, adopted from Bosman, has been +restored. It is also found in the Gaboon. It is strictly nocturnal, +and slower in its movements even than _Nycticebus tardigradus_, which +otherwise it much resembles in its habits. + +A second species, the Awantibo (_P. calabarensis_), rather smaller and +more delicately made, with smaller hands and feet and rudimentary tail, +constitutes the genus _Arctocebus_ of Gray. It is found at Old Calabar, +and is very rare, only a few individuals having as yet been met with. +Vertebræ: C 7, D 15, L 7, S 3, C 9.[656] + + +_Family_ TARSIIDÆ. + +Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total 34. The first upper +incisor large, and in contact with its fellow of the opposite side. +Canine of moderate size. Molars with numerous pointed cusps. Lower canine +semi-erect, its apex diverging from that of the single incisor. First +lower premolar smaller than those behind it. Orbit to a large extent +separated from the temporal fossa by a bony partition. Fibula slender, +with its lower half confluent with the tibia. Second and third digits of +the hind foot with compressed claws; all the other digits of both feet +with flat nails. Calcaneum and navicular bone of the foot elongated as in +the Chirogales and Galagos, but to a still greater extent. Colon short +and not folded. Vertebræ: C 7, D 13, L 6, S 3, C 27. + +_Tarsius._[657]—The family contains the single genus _Tarsius_, of which +but one species is known, _T. spectrum_, the Tarsier, a very singular +little animal, rather smaller than an English squirrel, with very large +eyes and ears, a long thin tail, tufted at the end, and immensely +elongated tarsal portion of the foot, in allusion to which its generic +name was given to it. It inhabits the forests of many of the islands of +the Indo-Malayan archipelago, including Sumatra, Borneo, Celebes, and +some of the Philippines, feeds chiefly on insects and lizards, sleeps +during the day, but is tolerably active at night, moving chiefly by +jumping from place to place, an action for which the structure of its +hind legs, which present a curious resemblance to those of a frog, seems +particularly well adapted. It is rare, not more than two being generally +found together, and only brings forth one young at a time.[658] + + +_Family_ CHIROMYIDÆ. + +Dentition of adult: _i_ ¹⁄₁, _c_ ⁰⁄₀, _p_ ¹⁄₀, _m_ ³⁄₃; total 18. +Incisors very large, compressed, curved, with persistent pulps and enamel +only in front, as in Rodents. Teeth of cheek series with flat, very +indistinctly tuberculated crowns. In the young the first set of teeth +more resemble those of the normal lemurs, being _i_ ²⁄₂, _c_ ¹⁄₀, _m_ +²⁄₂, all very small. Orbit surrounded by a ring of bone posteriorly, +beneath which it communicates freely with the temporal fossa. Fibula well +developed and distinct from the tibia. All the digits of both feet with +pointed rather compressed claws, except the hallux, which has a flattened +nail. Middle digit of the hand excessively attenuated. Vertebræ: C 7, D +12, L 6, S 3, C 27. + +[Illustration: FIG. 331.—Skull of Aye-aye (_Chiromys madagascariensis_). +× ⅙ Mus. Roy. Coll. Surgeons.] + +_Chiromys._[659]—This family, like the last, is formed for the +reception of a single genus, _Chiromys_,[660] containing one species, +_C. madagascariensis_, the Aye-aye, an animal about the size of a cat, +with a broad rounded head, short face, and large and naked ears. It has +very large hands and long thin fingers with pointed claws, one of which +(the middle or third) is remarkable for its extreme slenderness. The +foot resembles that of the other lemurs in its large opposable hallux, +with a flat nail, but all the other toes have pointed compressed claws, +like that of the second toe in the _Lemurinæ_ and the second and third +in the _Tarsiidæ_. Tail long and bushy. General colour dark brown, the +outer fur being long and rather loose, with a woolly undercoat. Mammæ +two, inguinal in position. It is a native of Madagascar, where it was +discovered by Sonnerat in 1780. The specimen brought to Paris by that +traveller was the only one known until 1860. Since then many others have +been obtained, and they may frequently be seen living in the gardens of +the Zoological Society of London. Like so many of the Lemurs, the Aye-aye +is completely nocturnal in its habits, living either alone or in pairs, +chiefly in the bamboo forests. Observations upon captive specimens have +led to the conclusion that it feeds principally on succulent juices, +especially of the sugar-cane, which it obtains by tearing open the hard +woody circumference of the stalk with its strong incisor teeth. It is +said also to devour certain species of wood-boring caterpillars, which +it obtains by first cutting down with its teeth upon their burrows, and +then picking them out of their retreat with the claw of its attenuated +middle finger. It constructs large ball-like nests of dried leaves, +lodged in a fork of the branches of a tree with the opening on one side. +The resemblance of its teeth to those so characteristic of the Rodentia +caused it to be placed formerly in that order, and it was only when its +anatomical characters were fully known that its true affinities with the +Lemurs became apparent.[661] + + +_Extinct_ LEMUROIDS. + +The discoveries of the last few years have revealed the former existence, +both in Europe and North America, of a number of extinct animals more +or less closely allied to the living Lemurs, which are of especial +interest as showing in some instances characters of a more generalised +type than is the case with the living representatives of the suborder. +It is, however, in some cases very difficult to determine whether these +extinct forms should be referred to the Lemuroidea or Insectivora; and +if those naturalists are right who regard these groups as survivors of a +very generalised ancestral type of mammalian organisation, it is to be +expected that as we recede in time we should find that the two groups +show more and more marked signs of a natural connection. The earliest +reference of one of these extinct Upper Eocene types to the Primates was +made in 1862 by Professor L. Rütimeyer, of Basle, who described part of +an upper jaw with three teeth from the so-called Bohnerz of Egerkingen, +near Soleure in Switzerland, under the name of _Cænopithecus lemuroides_, +regarding the animal to which the specimen belonged as partaking of +the characters both of the Lemurs and the American Monkeys. Most other +palæontologists refused, however, to accept this determination, and it +was not until many years later that the researches of Gaudry and Filhol +showed not only that _Cænopithecus_ was indeed a true Lemuroid, but also +that it was either identical with or closely allied to a form described +by Cuvier in the early part of this century under the name of _Adapis_ +and regarded as referable to the Ungulata. Later researches have brought +to light other Lemuroids in the Tertiaries of both the Old and the New +World; and it is very noteworthy that all these types seem to have +disappeared from both regions with the close of the upper portion of the +Eocene period. + +[Illustration: FIG. 332.—The last five right upper cheek-teeth of +_Microchœrus antiquus_ (_A_) and _Microchœrus erinaceus_ (_B_). Twice +natural size, and natural size.] + +Among the more interesting of the forms which are generally regarded +as true Lemuroids we may first mention a small species from the Quercy +Phosphorites, of which the hinder cheek-teeth are shown in Fig. 332, +_A_, which was originally described as _Necrolemur antiquus_, but +appears to be generically identical with _Microchœrus erinaceus_, of the +upper Eocene of Hampshire, of which the corresponding teeth are shown +in _B_ of the same figure. In this genus, according to Dr. Schlosser, +the dental formula is _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃, or the same +as in the existing _Tarsius_; but it is not improbable that in some +instances the first lower premolar may have been developed. The upper +molars of _M. erinaceus_ differ from those of _M. antiquus_ by the +simpler structure of their columns and the smaller size of the external +cingulum, which lacks the median cusp found in the latter. The angle of +the mandible is produced into a large hook-like flange which at once +distinguishes the genus from all existing Lemurs; and the anterior lower +premolar is not canine-like. _M. antiquus_ is of very small size, but +the larger _M. edwardsi_ of the same deposits comes nearer in dimensions +to _M. erinaceus_. The upper molars decrease in size from the first to +the third, the first and second having a median cusp in the external +cingulum, by which they are readily distinguished from the corresponding +teeth of the under-mentioned genus _Hyopsodus_. The third upper molar +differs from that of _Hyopsodus_ by its small size and the abortion of +its posterior columns. The skull approximates to that of the living genus +_Galago_, exhibiting the same inflation of the auditory bulla. The upper +molars are also not unlike one species of that genus, but the fourth +upper premolar has but one outer cusp, as in _Chirogaleus_. + +The small _Anaptomorphus_, from the North American Eocene, has a skull of +about the same size as that of the smallest species of _Microchœrus_, but +the dental formula is _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃, and the upper +molars are of the tritubercular type. + +[Illustration: FIG. 333.—The left upper cheek-teeth of _Adapis magna_, +from the Upper Eocene of Hampshire.] + +The well-known _Adapis_ (_Aphelotherium_ or _Palæolemur_), of the Upper +Eocene of France and England, differs from all existing Lemuroids in +possessing four premolars[662]; the dental formula being _i_ ²⁄₂, _c_ +¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃. The fourth upper premolar has two outer cusps, +and the upper molars (Fig. 333) resemble those of _Lepidolemur_ and +_Hapalemur_, while the lower canine is a well-developed tooth performing +the usual function of biting against the canine of the upper jaw. The +lower incisors have upright, spatulate crowns, as in the true Apes. The +skull is said to approximate in contour to that of _Propithecus_. The +typical _A. parisiensis_ is of comparatively small size, but the species +of which the upper cheek-teeth are shown in the woodcut is of much larger +dimensions. The skull of _A. magna_, which measures upwards of 4 inches +in length, resembles that of _A. parisiensis_ in its general characters, +but is modified much in the way that the skulls of larger animals differ +from the smaller ones of the same natural group. Thus the brain-chamber +and orbits are relatively smaller, the face larger, the muscular crests +more developed, and the constriction between the cerebral and the facial +portion of the skull more marked. These modifications remove the skull +in its general characters still farther from the existing Lemurs—so +much so that M. Filhol refers it and the other species of _Adapis_ to +a distinct zoological type, intermediate between the lemurs and the +pachyderms, to which he gives the name of _Pachylemuriens_, but later +researches do not support this view. As mentioned above, it has been +suggested that _Cænopithecus lemuroides_ is inseparable from _Adapis +parisiensis_, but the postero-internal column of the upper molars is said +to be larger. The genera _Tomitherium_ and _Notharctus_, of the Eocene +of the United States, appear to be allied to _Adapis_, but the second +has a larger lower canine. The same deposits have also yielded more or +less imperfect remains of other forms departing more widely from the +existing Lemuroid type. Of these _Hyopsodus_, of the Wasatch and Bridger +Eocene of the United States, has the dental formula _i_ ²⁄₂, _c_ ¹⁄₁, +_p_ ⁴⁄₄, _m_ ³⁄₅. The quadrituberculate upper molars have well-developed +accessory intermediate columns (protoconule and metaconule), and thus +resemble those of _Microchœrus_; the external surfaces of the outer +columns of their teeth being flattened, with vertical ridges and a +distinct cingulum. The third upper molar has its postero-internal column +(hypocone) partly aborted, but is otherwise as well developed as the +preceding molars. _Microsyops_, of the North American Eocene, appears +to have been an allied form in which there were probably only three +premolars. + +[Illustration: FIG. 334.—The right upper cheek-teeth of _Plesiadapis +remensis_; from the Lowest Eocene of Rheims. × ³⁄₂. _p_, 3, 4, premolars; +_m_, 1, 2, 3, molars. (From Osborn.)] + +The genera _Protoadapis_ and _Plesiadapis_, from the lowest Eocene of +Rheims, may not improbably be regarded as primitive Lemuroids. The lower +molars are quinquetubercular, and not unlike those of _Microsyops_; the +dental formula of the lower jaw is _i_ 2, _c_ 1, _p_ 3-4, _m_ 3 in the +first-named genus, but in the second the dentition is reduced to _i_ +²⁄₁, _c_ ¹⁄₀, _p_ ²⁄₂, _m_ ³⁄₃. In _Plesiadapis_ the lower and the first +upper incisor are enlarged, the upper molars (Fig. 334) tritubercular, +and the lower quadritubercular. _Indrodon_, of the lowest Eocene of the +United States, resembles _Plesiadapis_ in its tritubercular upper molars, +and appears to have a nearly similar dental formula. _Mixodectes_, of +the same deposits, was probably a more or less closely allied type. +_Pelycodus_ of the Wasatch Eocene of North America, in which the hallux +was not opposable, and _Cryptopithecus_ of the German Eocene, may be +regarded as very generalised Lemuroids. + + _Bibliography._—Besides the works and memoirs on particular + families and genera referred to above, see St. G. Mivart, + “Notes on the Crania and Dentition of the _Lemuridæ_,” in + _Proc. Zool. Soc._ 1864 (pp. 611-648) and 1867 (pp. 960-975); + Mivart and Murie, “On the Anatomy of the _Lemuroidea_,” in + _Trans. Zool. Soc._ 1872, vol. vii. pp. 1-113; W. Turner, “On + the Placentation of the Lemurs,” in _Phil. Trans._ vol. clxvi. + pp. 569-587; F. Pollen and D. C. Van Dam, _Recherches sur la + Faune de Madagascar_. 2ᵐᵉ parte, “Mammifères,” 1868. For the + fossil types see M. Schlosser, “Die Affen, Lemuren, etc., des + Europäischen Tertiärs,” in _Beitr. Pal. Œstr-Ungar_, 1888. + + +_Suborder_ ANTHROPOIDEA. + +This suborder includes the whole of the remaining members of the +Primates, namely, those animals commonly known as Marmosets, Monkeys, +Baboons, and Apes, together with Man himself. The characters by which +the Anthropoidea are distinguished as a whole from the Lemuroidea may be +summarised as follows. Skull with the orbit separated from the temporal +fossa by a vertical plate of bone joining the postorbital bar, and +the lachrymal foramen situated within the margin of the orbit. Pollex +sometimes rudimentary or absent; second digit of manus always well +developed, and that of the pes usually with a flattened nail (not so in +_Hapalidæ_). The cerebral hemispheres of the brain either completely +or almost completely cover the cerebellum, and are much convoluted. +Uterus not bicornuate. The placenta is deciduate and discoidal; and the +allantois is small. There are never abdominal mammæ. As additional points +of distinction from the Lemuroidea, it may be mentioned that the anterior +cornu of the hyoid is shorter than the posterior; the inner pair of upper +incisors are in contact in the middle line; and the transverse portion of +the colon extends uninterruptedly across the abdomen. + +The Anthropoidea may be divided into the five families—_Hapalidæ_, +_Cebidæ_, _Cercopithecidæ_, _Simiidæ_, and _Hominidæ_, of which the first +and second are confined to the New, and the third and fourth to the Old +World. + +In noticing some of the salient features in the external and internal +structure of the Anthropoidea it will be found convenient to allude to +all the members of the first four families as Apes, in contradistinction +to Man. In respect to relative size the extremes are found in the Gorilla +on the one hand and _Hapale_ on the other; the difference in this +respect between these two forms being greater than that between Man and +a Squirrel. The relative proportions between the limbs and the body, and +also between the fore and hind limbs, are subject to great variation. +Thus in _Hylobates_ and _Ateles_ both pairs of limbs are much elongated; +in the former case the pectoral being much longer than the pelvic pair +(Fig. 335). In other cases, as in the Orang (Fig. 354), while the arms +are very long, the legs are short; but in the subfamily _Cercopithecinæ_ +both pairs are short and subequal. Only in the _Hapalidæ_ and some of the +_Cebidæ_ are the legs proportionately as long as in Man. + +The tail is as much as three times the length of the body in _Ateles_; +while in the _Simiidæ_ it is totally absent. In the majority of genera it +is long in all the species; but in some cases, as in _Macacus_, it may be +either long, short, or absent in the different species of a single genus. + +Equally marked variations occur in the shape of the head. Thus in +_Ateles_ it is rounded; while in the Orang it is elevated vertically; +in _Chrysothrix_ it is produced posteriorly; and in the Baboons +(_Cynocephalus_) it is characterised by the great production of +the muzzle and the terminal position of the nostrils, whereby a +characteristic Dog-like form is assumed. The eyes are always directed +forwards, and are never more separated from one another than in Man, +although, as in _Chrysothrix_, they may be closer together. They are +of very large size in _Nyctipithecus_, while in the Baboons they are +relatively small in proportion to the size of the head. The ears +are invariably well developed, and are usually pointed at their +postero-superior angle. Those of man are characterised by the soft +depending portion known as the “lobule,” of which there is a rudiment +in the Gorilla. In the majority of Apes the nose is but very slightly +prominent; but it attains an extraordinary development in _Nasalis +larvatus_, and is scarcely less remarkable in _Semnopithecus roxellanæ_ +(Fig. 349). Among the Gibbons the Hoolock has a distinctly aquiline nose. +The nostrils are terminal in the true Baboons; and while in all the Old +World Apes they are approximated, in those of the New World they are +separated by a broad septum. With the exception of the Orang, the lips of +the Apes are thin. + +The pollex makes a nearer approach in form to the human thumb in the +Chimpanzee than in any other Ape. Man differs from all the Apes in having +the hallux frequently longer instead of shorter than the other digits of +the foot. The hallux of the Orang is peculiar in having no nail, but in +other cases the nail is flat; the nails of the other digits of the Apes +are never quite flat, and in some of the _Cebidæ_ they are decidedly +compressed laterally, while in the _Hapalidæ_ they assume the form of +sharp and curved claws. + +All the Apes have the greater part of the body well clothed with hair. In +the Gibbons and the _Cercopithecidæ_ the buttocks have naked ischiatic +callosities, which attain their greatest development in _Cynocephalus_ +and its allies. The male of the Orang has a well-developed beard, and in +_Cercopithecus diana_ there is long hair on the cheeks and chin, while +in _Macacus silenus_ the face is surrounded by a fringe of long hair, +separated by an interval on the forehead. Long hair is found on the +head in _Hapale œdipus_ and in some species of _Semnopithecus_; while +in the Bonnet Monkey (_Macacus sinicus_) it radiates in all directions +from a central point on the vertex. Long hair clothes the shoulders +in _Cynocephalus hamadryas_ and _Hapale humeralifer_; and the end of +the tail has a tuft in two species of _Cynocephalus_ and in _Macacus +sinicus_. Many of the African _Colobi_ and some species of the Howlers +have very long hair on the flanks; and in _Pithecia_ this development of +hair extends to the greater part of the body and the tail, _P. satanas_ +also having a long beard. In all the lower Apes the hairs on the arm and +forearm are directed towards the hand quite down to the wrist; and the +same arrangement obtains in _Hylobates_. In the other _Simiidæ_, however +(as in man), the points of the hairs of the arm and forearm converge +at the elbow. Darwin’s explanation of this peculiarity is that these +Apes are accustomed to sit with the arms bent, so that the rain is thus +enabled to run off at the elbow. + +In one species of _Hapale_ the hair is of a silky texture, and in the +South American _Eriodes_, and _Macacus tibetanus_ (as in all the mammals +inhabiting the arid and severe climate of Tibet) it becomes woolly. + +The development of very brilliant colours on the naked parts of the body, +such as the face, sexual organs, and ischiatic callosities is a marked +feature of many of the _Cercopithecidæ_ and some other Apes. + +With the exception of the long tail found in most forms, the general +structure of the skeleton of the Apes is very similar to that of man, +but there are marked differences in the form of the jaws and of the +innominate bones. The proportion of the facial to the cranial region +of the skull varies with the shape of the head, of which brief mention +has already been made; the greatest development of the facial portion +being in the Baboons. Curiously enough, some of the lower American +Monkeys, and more especially _Chrysothrix_, have the greatest relative +development of the cranial part of the skull of all the Apes; this +character being, however, one common to all the smaller representatives +of particular groups, and obviously necessary to provide the requisite +amount of brain-space. In the convexity of the frontal region of the +skull the American forms, and more especially _Pithecia_, make the +nearest approximation to man, and the same is true with regard to the +occipital production, which is most developed in _Chrysothrix_. Most of +the _Simiidæ_ exhibit, however, a distinct convexity of the occiput, +and thereby differ markedly from the _Cercopithecidæ_, in which this +region is flat. The rotundity of the cranium is obscured in the larger +Apes, such as the Orang (Fig. 353) and Gorilla, by the development of +prominent bony ridges for muscular attachment; these attaining their +maximum in the males of the species last named, where the sagittal crests +and the supraorbital ridges are very prominent. The mastoid process is +always smaller in the Apes than in Man, and as it diminishes in size the +petrosal tends to assume an inflated or bullate condition. The orbits in +shape are most like that of Man in the Gorilla; and, in accordance with +the size of the eyes, they are of enormous dimensions in _Nyctipithecus_. + +The angle formed by the plane of the foramen magnum with that of the +basicranial axis is subject to variation according to the degree of +convexity of the occiput, but is generally smaller than in Man, although +larger in _Chrysothrix_. There is an external bony meatus auditorius in +Man, the _Simiidæ_, and the _Cercopithecidæ_, but none in the _Cebidæ_ +and _Hapalidæ_. + +The premaxillæ of the Apes are always large; and, except in the +Chimpanzee, the premaxillo-maxillary suture persists until after the +permanent dentition has been developed. The nasals are smaller and +flatter than in Man, but are largest in _Mycetes_. The two rami of the +mandible are invariably completely ankylosed at the symphysis in the +adult. The Siamang (_Hylobates syndactylus_) is the only ape in which the +mandibular symphysis slows a slight projection in front corresponding +to the human chin. In _Mycetes_ the angle of the mandible attains an +enormous development (Fig. 338) to protect the huge inflated basihyal. +The frontal sinuses, though present, in the _Simiidæ_, are generally +replaced in the _Cercopithecidæ_ by a coarse diploë, but they are present +in the _Cebidæ_ and _Hapalidæ_, being especially large in _Cebus_. In +fully adult individuals the cranial sutures become obliterated, the +internasal suture disappearing at an early age in the _Simiidæ_ and most +of the _Cercopithecidæ_. As in many Carnivora, the tentorium, or membrane +separating the cerebrum from the cerebellum, may become ossified in some +of the American forms. + +The number of the teeth in the Old World Apes is invariably the same as +in Man, namely _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃, total 32; but in the +_Cebidæ_ the cheek-teeth are _p_ ³⁄₃, _m_ ³⁄₃, and in the _Hapalidæ_ _p_ +³⁄₃, _m_ ²⁄₂. It is probable that the two pairs of incisors correspond +to the first and third of the typical series of three. In all Apes the +dental series is interrupted by a diastema, and the canines of the +males are large. Man alone has an uninterrupted dental series of a +horse-shoe-form, without prominent canines. + +According to recent researches the Chimpanzee and some of the other +_Simiidæ_ exhibit a more or less close approximation to the sigmoid +curvature of the vertebral column which is so characteristic of Man, +and there is also some approach to it in the Baboons. The number of +dorsal vertebræ in the Apes may vary from eleven, as in some species +of _Cercopithecus_ and _Macacus_, to fourteen in certain forms of +_Hylobates_, and to fifteen in _Nyctipithecus_. The _Cebidæ_ generally +have thirteen; and the same number obtains in the Chimpanzee and Gorilla, +while the Orang resembles Man in having but twelve. The lumbar vertebræ +show a range in number of from four to seven. In the _Simiidæ_ there are +four or five of these vertebræ, the length of the lumbar region being +shorter in this family than in the other Apes, with the exception of +_Ateles_. The shortness of the lumbar region in the last-named genus is +compensated by the relative length of the dorsal region, as is shown in +Fig. 335. + +[Illustration: FIG. 335.—Skeleton of the Black-handed Spider Monkey +(_Ateles geoffroyi_). From De Blainville.] + +The sacrum is longest in the _Simiidæ_ and Man, its greatest absolute +length occurring in the Gorilla, and the relative greatest length being +found in _Hylobates_. The _Simiidæ_ never have less than five, and may +have six sacral vertebræ; while in the lower forms there are generally +only two or three, although occasionally four in some of the American +forms. The Orang and some of the Baboons make the nearest approximation +to Man in the marked angle formed at the junction of the sacrum with +the lumbar vertebræ. Except in the _Simiidæ_ and _Macacus inuus_, the +number of caudal vertebræ in the Apes always exceeds four, but they may +be reduced to five in the Mandrill (_Cynocephalus maimon_). In _Macacus_ +and _Uacaria_ the shortness of the tail is attained by the small size +of the vertebræ themselves, the number of which may be from fifteen to +seventeen. Other forms usually have from twenty to thirty-three caudals, +the latter number occurring in _Ateles_ (Fig. 335), where the tail is +relatively the longest. The tail is, however, absolutely longest in +_Semnopithecus_, _Colobus_, and their allies, the length being partly +due to the size of the component vertebræ. Chevron bones are present in +all forms having a distinct tail; and, together with other processes for +muscular attachment, attain their greatest development in _Ateles_. + +The vertebral processes known as metapophyses and anapophyses, which +are generally inconspicuous in Man, and are but small in the _Simiidæ_, +attain a large development in the lower forms. The metapophyses +generally commence in the eighth or ninth dorsal, and continue to the +anterior caudals, where they gradually merge in the prezygapophyses. +The anapophyses, which are most developed in the _Cebidæ_, project +outwards and backwards from one vertebra to embrace the prezygapophyses +of the succeeding one. They occur generally in the same region as the +metapophyses, but usually cease at the penultimate lumbar, although in +some cases they can be traced on to the posterior cervicals and anterior +caudals, in the latter region passing into the transverse processes. + +In most Apes the sternum is narrow, and consists of a more or +less enlarged manubrium, followed by a chain of subequal and +antero-posteriorly elongated bones, from three to six in number. In +the _Simiidæ_ alone is there a broad sternum, or one consisting of a +manubrium, followed by a single bone only, as in _Hylobates_. The Orang +presents a peculiarity, in that the sternum long remains made up of +ossifications arranged in pairs, side by side, successively. The true +ribs are seven in number on each side in the highest forms, but in +_Hylobates_ there are sometimes eight. In _Ateles_ there are sometimes +nine pairs. In _Hapale_ the number varies from six to eight, and it is +seven or eight in the other genera. The angles of the ribs are never so +marked as in Man; although most marked in _Hylobates_. _Pithecia_ is +distinguished by the greater relative breadth of the ribs. In no Ape is +the thorax half as broad again as it is deep from back to breast; but in +the _Simiidæ_ its transverse diameter exceeds its depth by from about +one-fourth to a little under one-third of the latter. In _Ateles_, and +sometimes in _Mycetes_, the thorax is wider than deep, but in all the +rest it is deeper than wide. + +In regard to the appendicular skeleton it may be observed that the +Gorilla and Orang make the nearest approach to Man in the form of the +scapula; and that the supraspinous fossa of this bone is largest in +_Gorilla_ and _Mycetes_, being remarkably small in _Simia_. The _Cebidæ_ +have a distinct suprascapular notch which is often converted by a bar of +bone into a foramen; this bar in _Mycetes_ giving rise to a peculiar flat +process. The acromion and coracoid processes are most developed in the +_Simiidæ_ and _Ateles_. + +The relative length of the fore and hind limbs has been already briefly +touched upon. The humerus closely resembles that of Man throughout the +suborder; the nearest approximation occurring in the _Simiidæ_. As in the +Lemuroidea, this bone never has an entepicondylar foramen, but in many +of the American forms it has a supracondylar perforation. The radius and +ulna, like the tibia and fibula, are always perfectly distinct throughout +their length; and the hand can be pronated and supinated upon the +forearm. Man, the Gorilla, and the Chimpanzee differ from other forms in +having no os centrale in the carpus. + +The brain of Apes is always much smaller in absolute dimensions than in +Man. Thus, according to Professor Mivart,[663] “the cranial capacity is +never less than 55 cubic inches in any normal human subject, while in +the Orang and Chimpanzee it is but 26 and 27½ cubic inches respectively. +The relative size of the brain varies inversely with the size of the +whole body, but this is the case in warm-blooded vertebrates generally. +The extreme length of the cerebrum never exceeds, as it does in Man, two +and a quarter times the length of the basicranial axis. The proportion +borne by the brain to its nerves is less in the Apes than in Man, as also +is that borne by the cerebrum to the cerebellum. In general structure +and form the brain of Apes greatly resembles that of Man. Each half +of the cerebrum contains a triradiate lateral ventricle, and though +in some _Cercopithecidæ_ the posterior cornu is relatively shorter +than in man, it again becomes elongated in the _Cebidæ_, and in many +of the latter it is actually longer relatively than it is in man. The +posterior lobes of the cerebrum are almost always so much developed as +to cover over the cerebellum, the only exceptions being the strangely +different forms _Mycetes_ and _Hylobates syndactylus_. In the latter +the cerebellum is slightly uncovered, but it is so considerably in the +former. In _Chrysothrix_ the posterior lobes are much more largely +developed relatively than they are in man. The cerebrum has almost always +a convoluted external surface. In this group, however, as in mammals +generally, a much-convoluted cerebrum is correlated with a considerable +absolute bulk of body. Thus in _Hapale_ (and there only) we find the +cerebrum quite smooth, the only groove being that which represents the +Sylvian fissure. In _Simia_ and _Gorilla_ and _Anthropopithecus_, on the +contrary, it is very richly convoluted. A hippocampus minor is present +in all Apes, and in some of the _Cebidæ_ it is much larger relatively +than it is in Man, and is absolutely larger than the hippocampus major. +Of all Apes, the Orang has a brain which is most like that of Man; +indeed, it may be said to be like Man’s in all respects, save that it +is much inferior in size and weight, and that the cerebrum is more +symmetrically convoluted and less complicated with secondary and tertiary +convolutions. If the brain of _Simia_ be compared with that of _Gorilla_ +and _Anthropopithecus_, we find the height of the cerebrum in front +greater in proportion in the former than in the latter; also the bridging +convolutions, though small, are still distinguishable, while they are +absent in the Chimpanzee. Nevertheless this character cannot be of much +importance, since it reappears in _Ateles_, while two kinds of the genus +_Cebus_ (so closely allied as to have been sometimes treated as one +species) differ strangely from each other in this respect. The corpus +callosum, in Apes generally, does not extend so far back as in Man, and +it is very short in _Pithecia_. In the Orang and Chimpanzee there are, +as in Man, two corpora albicantia, while in the lower Monkeys there is +but one. The vermis of the cerebellum is larger in the _Cebidæ_ than +in the _Simiidæ_ and _Cercopithecidæ_. In all Apes below the _Simiidæ_ +each lateral lobe of the cerebellum gives off a small lobule, which is +received into a special fossa of the petrous bone. Certain prominences +of the medulla oblongata, termed corpora trapezoidea, which are found in +lower mammals, begin to make their appearance in the _Cebidæ_.” + +The organs connected with the functions of alimentation, circulation, +and excretion, as well as the muscles, conform generally to the type +obtaining in Man, of which full description will be found in works on +human anatomy. The tongue is longer in Apes than in Man; and a uvula is +generally present, although rudimentary in the _Cebidæ_. The peculiar +sacculation of the stomach in the subfamily _Semnopithecinæ_ has been +already mentioned; this sacculation is most developed at the cardiac +extremity, where it somewhat resembles a colon spirally coiled. In +_Hylobates_ the stomach is very like that of Man, differing only in the +more elongated and distinct pylorus. _Pithecia_ has a more globular +stomach, while in _Hapale_ the cardiac and pyloric apertures are +approximated. The intestine of Apes is devoid of valvulæ conniventes, +and it is only in Man and the _Simiidæ_ that the colon is furnished with +a vermiform appendage. The colon varies from a fully sacculated form in +_Hylobates_ to a smooth one in _Cebus_. + +The liver of Apes is subject to a considerable amount of variation. In +the _Simiidæ_ it comes more or less close to the human type; that of +the Orangs being usually divided only into two principal lobes by the +umbilical vein, and showing no trace of lateral fissures. In the Gorilla +these fissures are present, so as to produce right and left lateral +and central lobes. _Hylobates_ has a liver (Fig. 352) which perhaps +is nearer to the human than that of any of the other _Simiidæ_. In the +_Cercopithecidæ_ the liver differs from that of the _Simiidæ_ by the +deeply cleft lateral fissures, and has a comparatively small and pointed +caudate lobe. The enormous size of the stomach in _Colobus_ causes the +liver to be very narrow, and pushed to the left side. The liver of the +_Cebidæ_ (Fig. 336) and _Hapalidæ_, in addition to the deeply cleft +lateral fissures, is characterised by the great size and quadrangular +form of the caudate lobe (_c_), which attains its maximum development in +_Ateles_. The gall-bladder is always present. + +[Illustration: FIG. 336.—Under surface of the liver of the Black-handed +Spider Monkey (_Ateles melanochir_). _u_, Umbilical fissure; _vc_, vena +cava; _ll_, left lateral lobe; _lc_, left central lobe; _rc_, right +central lobe; _rl_, right lateral lobe; _s_, Spigelian lobe; _c_, caudate +lobe; _g_, gall-bladder.] + +The larynx is in many Apes furnished with sac-like appendages, which are +variable in different species as regards number, size, and situation. +They may be dilatations of the laryngeal ventricle, as in _Simia_, +_Gorilla_, and _Anthropopithecus_, or they may open above the false +vocal chords so as to be extensions of the thyro-hyoid membrane, +as in _Hylobates_. There may be but a single median opening in the +front part of that membrane at the base of the epiglottis, as in the +_Cercopithecidæ_. There may be a single median opening at the back of the +trachea, just below the cricoid cartage, as in _Ateles_; there may be but +a single sac, or there may be five, as sometimes in _Mycetes_. These may +be enormous, meeting in the middle line in front and extending down to +the axillæ, as in the Gorilla and Orang. A sac may occupy the cavity of +the expanded body of the hyoid, as in _Mycetes_. + +The hyoid has its basilar part generally somewhat more convex and +enlarged than in Man; but in _Mycetes_ it becomes greatly enlarged and +deeply excavated, so as to form a great bony bladder-like structure. The +posterior cornua of the hyoid (thyrohyals) are never entirely absent, but +the anterior or lesser cornua may be so, as in _Mycetes_. The anterior +cornua never exceed the posterior cornua in length; but they may be +(_e.g._ in _Cercopithecus_) more largely developed relatively than in +Man, and may even be jointed, as in _Lagothrix_. + +The lungs have generally the form of those of man; but the right lung +may have four lobes, as in _Hylobates_. The great arterial trunks in +_Simia_, _Gorilla_, and _Anthropopithecus_ are arranged as in Man. In +_Hylobates_ and the lower Apes, however, the left carotid artery may take +its origin from the innominate artery. + +In regard to their distribution in time the earliest record that we as +yet have of the occurrence of Apes is in the Middle Miocene of Europe, +where forms are met with apparently so closely allied to some of the +higher existing types that it is evident we must look much farther +back before we can get any clue to the origin of the suborder. Since +all the known fossil Old World Apes are referable to the _Simiidæ_ or +_Cercopithecidæ_, and no representatives of these families have been +obtained from the Tertiaries of America, it would appear that the +distinction of the Apes of the Old World from those of the New is of very +old standing. + +At the present day Apes are mainly confined to tropical and subtropical +regions. In the Old World _Macacus inuus_ is found as far north as +Gibraltar, _M. tibetanus_ and _Semnopithecus roxellanæ_ inhabit western +Tibet, while in Japan we have _M. speciosus_. In the New World one +species of _Ateles_ is known to occur as far north as latitude 19° in +Southern Mexico, and may range a few degrees higher. To the southward +species are found near the Cape, in Timor, and the Malay Archipelago; +while in America they range in Brazil and Paraguay to about latitude 30°. +The Tibetan species are found at a very high elevation; and in the outer +Himalaya the Langurs (_Semnopithecus_) may be seen in winter and spring +leaping from bough to bough of snow-covered pines. + +Apes are very abundant in the Ethiopian and Oriental regions, as well as +in that part of America which extends from Panama to Southern Brazil. +Ceylon, Borneo, Sumatra, and Java may be mentioned as islands where +Ape-life attains great development; but they are unknown in Madagascar +and the West Indian Islands, and of course in the Australasian region. + +We have already alluded to the circumstance that while the _Simiidæ_ +and _Cercopithecidæ_ are exclusively confined to the Old World, the +_Cebidæ_ and _Hapalidæ_ are equally restricted to the New, and we may +accordingly proceed to notice a few points in relation to generic +distribution. Of the larger _Simiidæ_ the Gorilla and Chimpanzee +are confined to Equatorial Africa, and the Orang to Malayana; but +there is evidence of the former existence of a species of Chimpanzee +(_Anthropopithecus_) and not improbably of an Orang (_Simia_) in Northern +India. The Gibbons (_Hylobates_) are now exclusively Oriental. Europe +has only _Macacus inuus_ of Gibraltar, also found in Africa north of +the Sahara, and therefore strictly Palæarctic in distribution. The +Ethiopian region includes in the _Cercopithecidæ_ the genus _Colobus_ +(the African analogue of _Semnopithecus_), _Cercopithecus_, and the +Baboons (_Cynocephalus_, etc.) The Baboons range, however, into Arabia +and Syria, and also existed during the Pliocene epoch in Northern +India. _Semnopithecus_ and _Macacus_ are very characteristic of the +Oriental region; but, as already mentioned, outlying species extend into +various parts of the Palæarctic region. _Macacus_ has indeed a very +wide distribution, extending from Gibraltar and North Africa to Japan. +The allied _Cynopithecus_, represented only by _C. niger_ of Celebes, +approximates to the Baboons; while the one species of _Nasalis_ is +peculiar to Borneo. Remains of _Semnopithecus_ and _Macacus_ occur in the +Tertiaries of India and Europe, which also yield allied extinct types +noticed in the sequel. + +In America, north of Panama, the genera known to be represented are +_Chrysothrix_, _Nyctipithecus_, _Cebus_, _Ateles_, _Mycetes_ and _Hapale_ +in Veragua; _Nyctipithecus_, _Cebus_, _Ateles_, and _Mycetes_ in Costa +Rica and Nicaragua; _Ateles_ and _Mycetes_ in Guatemala; and _Ateles_ +in Southern Mexico. Brazil is the headquarters of the American Apes; +but different portions of that vast region have a somewhat distinct +Ape fauna. Thus the genus _Eriodes_ appears in South-Eastern Brazil +to represent the species of _Ateles_ inhabiting the more northern and +western parts of the empire. Southwards, the genera _Cebus_, _Mycetes_, +_Chrysothrix_, and _Callithrix_ extend farthest; but they do not probably +all extend to the farthest limit yet known, namely 30° S. The species +found farthest south are _Mycetes caraya_, _Cebus fatuellus_, and +_Callithrix personatus_. + + +_Family_ HAPALIDÆ. + +Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ²⁄₂; total 32. No bony external +auditory meatus, a broad internarial septum, and no cheek-pouches. Tail +non-prehensile; no ischiatic callosities. Pollex not opposable; a long, +curved, and pointed claw to all the digits except the hallux. + +This family, which includes the smallest representatives of the suborder, +commonly known as Marmosets, is confined to the New World. In addition +to the diagnostic characters given above, it may be mentioned that the +pollex is elongated and the hallux very small, while the pectoral limbs +are not longer than the pelvic pair; and the tail is long and more or +less thickly covered with elongated hairs. + +The dentition of the Marmosets sufficiently distinguishes them from all +other members of the suborder, although they are evidently nearly allied +to the _Cebidæ_. The small size of the hallux, and the total incapacity +of the pollex to oppose itself in the least degree to the other digits, +as well as the presence of claws on all the digits of the manus, are, +however, equally characteristic features. These animals (Fig. 337) are +not larger than Squirrels, and are of active arboreal habits, living +in small companies, and adding insects to the ordinary fruit diet. +Frequently, as in the figured species, the head is furnished on either +side with a long tuft of hair projecting outwards and backwards. They +give birth to as many as three young ones at a time, and thereby differ +from all other members of the suborder, in which one is the normal +number. They are divided into two genera, according to the proportionate +size of the lower canine to the incisors; but some species present an +intermediate condition, so as to render this distinction of somewhat +doubtful value. + +_Hapale._[664]—Lower canine not longer than the incisors. A number of +species have been described, among which may be mentioned _H. jacchus_, +_H. albicollis_, _H. aurita_, and _H. humeralifer_. Remains of species of +this genus have been found in the cavern-deposits of Brazil. + +[Illustration: FIG. 337.—The Golden Marmoset (_Midas chrysoleucas_). From +_Proc. Zool. Soc._ 1868, pl. 24.] + +_Midas._[665]—Lower canine considerably longer than the incisors. No +less than twenty-four species of this genus have been named, among +which the Silky Marmoset (_M. rosalia_) of Columbia, the Pinche Monkey +(_M. œdipus_) of South-Eastern Brazil, and the Golden Marmoset (_M. +chrysoleucas_, Fig. 337) are well-known types. + + +_Family_ CEBIDÆ. + +Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total 36. Tail frequently +prehensile; digits with nails; other characters as in the _Hapalidæ_. + +The members of this American family are at once distinguished by the +dental formula, which is numerically higher than in any other Apes. +The various species range over the whole of tropical America, but are +most abundant in the dense forest regions of Brazil, where they live +a completely arboreal life, to which the prehensile tails of many of +them are so specially adapted. They are in most respects closely allied +to the _Hapalidæ_, but the pollex diverges somewhat from the plane of +the other digits; while the retention of the third molar is a very +distinctive feature. None of the species attain the dimensions of the +larger _Cercopithecidæ_ of the Old World. The genera are usually arranged +in five subfamilies. + +Subfamily =Mycetinæ=.—Lower incisors vertical; hyoid bones enormously +inflated; tail long and prehensile, naked beneath at the end; pollex well +developed. + +[Illustration: FIG. 338.—Side view of skull and hyoid bone of the Red +Howling Monkey (_Mycetes seniculus_). From De Blainville.] + +_Mycetes._[666]—The sole representatives of this subfamily are the +well-known Howling Monkeys, all of which are included in the genus +_Mycetes_. They are of more bulky build, and have more produced muzzles +than the other members of the family. The truncated occipital region, and +the extraordinary development of the rami of the mandible, especially +of their angular and ascending portions, are the chief peculiarities +by which the skulls (Fig. 338) of the members of this genus are +characterised. The last named character, which is more marked in the male +than in the female sex, is related to the enormous size of the vocal +organs, which the rami of the mandible enclose and protect. The inflated +hyoid bone, which forms a deep cup, is shown in the figure. The Howlers +are subject to great individual and sexual variation of colours, so that +the discrimination of species from local races is difficult. In one +species the male is black and the female straw-coloured; and several of +the species have bright red or golden hair on the flanks. In disposition +these creatures are sluggish and stupid, but their chief characteristic +is their prodigious power of voice. Mr. Bates, in his _Naturalist on the +Amazons_, observes that “when Howlers are seen in the forest there are +generally three or four of them mounted on the topmost branches of a +tree. It does not appear that their harrowing roar is emitted from sudden +alarm; at least it was not so in captive individuals. It is probable, +however, that the noise serves to intimidate their enemies.” + +Several species have been described, the Red Howler (_M. seniculus_) and +the Ursine Howler (_M. ursinus_) being well-known forms. Remains of this +genus probably referable to existing types are found fossilised in the +cavern-deposits of Brazil. An allied fossil form from the South American +Pleistocene has been described as _Protopithecus_. + +Subfamily =Pitheciinæ=.—Lower incisors inclined forward at their +summits; hyoid bone normal; tail long or short, non-prehensile; pollex +well developed. Two genera are included in this subfamily, readily +distinguished by the length of the tail. + +_Pithecia._[667]—The Sakis, as the representatives of this genus are +commonly termed, are readily characterised by the length of the tail; the +angle of the mandible is expanded, although less so than in _Mycetes_. A +number of species have been described, the Black Saki (_P. satanas_) of +the Lower Amazons, being one of the best known. While some species, like +_P. hirsuta_, have long hair covering the whole of the head, body, and +tail, in others only the head, or the cheeks and chin, are so clothed. + +_Uacaria._[668]—The Uakari Monkeys differ from all the other _Cebidæ_ +by their short Baboon-like tail. The Bald Uakari (_U. calva_) of the +Rio Negro, and the closely allied _U. rubicunda_ of the Upper Amazons, +are remarkable for their scarlet face, which forms a striking contrast +to the long, silky, whitish hair covering the body. According to Mr. +Bates, the Uakaris live in forests which are inundated during a great +part of the year, and never descend to the ground; they appear to be +rare and of local distribution. The third species, _U. melanocephala_, +differs considerably from both the others. The cæcum of _U. calva_, +according to Mr. F. E. Beddard, measures upwards of “10 inches along +the greater curvature; it is separated from the colon by a very marked +constriction; it is not sacculated, and when fully distended with air is +curved on itself into a little less than a circle; it is furnished with a +well-developed median frenum carrying blood-vessels.” A similar type of +cæcum is also found in _Callithrix_ and _Pithecia_. + +Subfamily =Nyctipithecinæ=.—Lower incisors vertical; hyoid normal; tail +long, non-prehensile; pollex well developed. + +Three genera are included in this subfamily, the species being partly +insectivorous. + +[Illustration: FIG. 339.—The Moloch Teetee (_Callithrix moloch_). From +_Archives du Muséum_, vol. iv. pt. 3.] + +_Callithrix._[669]—Head small, depressed, and not elongated; nares widely +separated; canines small; angle of mandible expanded as in _Pithecia_; +tail with long hair. + +This genus comprises several small species, mostly from Brazil and the +Amazons, and commonly known as Teetees, one of the best-known species +(_C. moloch_, Fig. 339) being represented in the accompanying woodcut. +The smaller eyes and the more widely separated nostrils distinguish them +from _Nyctipithecus_; while the small canines and the bushy tail readily +mark their distinction from _Chrysothrix_. Remains of _Callithrix_ have +been found in the Brazilian caves. + +_Chrysothrix._[670]—Head greatly elongated; orbits large and closely +approximated; canines well developed; tail with comparatively short hair. + +[Illustration: FIG. 340.—The Lemurine Douroucouli (_Nyctipithecus +lemurinus_). From _Archives du Muséum_, vol. iv, pl. 2.] + +The small Squirrel Monkeys, of which four species have been described, +are characterised by the great backward projection of the occipital +region of the skull, and by orbits approximating in size to those of the +next genus. + +_Nyctipithecus._[671]—Head rounded; orbits very large, separated by a +narrow septum; nares somewhat approximated. + +The Douroucoulis (Fig. 340), as the members of this genus are called, are +of nocturnal habits, in association with which the eyes are of enormous +dimensions, as in the Lemuroid genus _Loris_. The following account, of +two species of this genus is taken from Mr. Bates’s _Naturalist on the +Amazons_: “They sleep all day long in hollow trees, and come forth to +prey on insects and eat fruit only in the night. They are of small size, +the body being about a foot long, and the tail 14 inches, and are thickly +clothed with soft gray and brown fur, similar in substance to that of the +Rabbit. Their physiognomy reminds one of the Owl or Tiger-Cat; the face +is rounded and encircled by a ruff of whitish fur; the muzzle is not at +all prominent; the mouth and chin are small; the ears are very short, +scarcely appearing above the hair of the head; and the eyes are large +and yellowish in colour, imparting the staring expression of nocturnal +birds of prey. The forehead is whitish, and decorated with black stripes, +which in one of the species (_N. trivirgatus_) continue to the crown, +and in the other (_N. felinus_) meet on the top of the forehead. _N. +trivirgatus_ was first described by Humboldt, who discovered it on the +banks of the Cassiquiare, near the headquarters of the Rio Negro.” + +Subfamily =Cebinæ=.—Lower incisors vertical; hyoid bone normal; tail long +and prehensile; pollex present or absent. + +This subfamily includes the typical members of the family, which are +arranged in four genera. + +_Ateles._[672]—Form slender; limbs very long; fur not woolly; pollex +absent; tail naked beneath distally; nails not much laterally compressed +and pointed. + +This genus includes the well-known Spider Monkeys (Fig. 341), which by +their long limbs and tail are admirably adapted to a purely arboreal +life, although they lack the active and agile habits of the Old World +Gibbons. The tail with the under surface of its extremity naked affords +the most completely prehensile type of this organ, and can sustain the +weight of the whole body. Objects are not unfrequently grasped by it and +brought within reach of the hand or mouth. Owing to the absence of the +pollex the power of grasping is very imperfect in the hand. At least +fourteen species of this genus have been described, among the best-known +being _A. melanochir_ (Fig. 341), _A. paniscus_ of Guiana, _A. geoffroyi_ +of Central America, _A. ater_ of Eastern Peru, and _A. hybridus_ of +Colombia. + +_Eriodes._[673]—Form slender; limbs very long; fur woolly; internasal +septum narrower than usual in the family; pollex rudimentary; tail naked +beneath distally; nails exceedingly compressed laterally, and pointed. + +This genus is represented by three species from South-East Brazil, which, +while closely allied to the true Spider Monkeys, differ by their woolly +hair, the narrow internasal septum, the presence of a rudimentary pollex, +and the great compression of the nails. The species are _E. arachnoides_, +_E. hemidactylus_, and _E. hypoxanthus_. + +_Lagothrix._[674]—Form rather robust; limbs moderate; fur woolly; pollex +well developed; tail distally naked beneath. + +[Illustration: FIG. 341.—The Black-handed Spider Monkey (_Ateles +melanochir_). From _Proc. Zool. Soc._ 1871, pl. 15.] + +The Woolly Monkeys differ from the preceding genera by the presence +of a well developed pollex. They resemble _Eriodes_ in their fur and +compressed nails, but differ in the more widely separated nares. The tail +resembles that of the preceding genera. Speaking of these Monkeys Mr. +Bates observes that “the Barrigudos are very bulky animals, whilst the +Spider Monkeys are remarkable for the slenderness of their bodies and +limbs. I obtained specimens of what have been considered two species, +one (_L. olivaceus?_) having the head clothed with gray, the other (_L. +humboldti_, Fig. 342) with black fur. They both live together in the same +places, and are probably only differently coloured individuals of one and +the same species. I sent home a very large male of one of these kinds, +which measured 27 inches in length of trunk, the tail being 26 inches +long; it was the largest monkey I saw in America, with the exception of +a black Howler, whose body was 28 inches in height. The skin of the face +in the Barrigudo is black and wrinkled, the forehead is low, with the +eyebrows projecting.... In the forests the Barrigudo is not a very active +animal; it lives exclusively on fruits, and is much persecuted by the +Indians on account of the excellence of its flesh as food.” Five species +are usually recognised, viz. _L. canus_, _L. humboldti_, _L. castelnaui_, +_L. tschudii_, and _L. geoffroyi_. + +[Illustration: FIG. 342.—Humboldt’s Lagothrix (_Lagothrix humboldti_). +From _Proc. Zool. Soc._ 1863, pl. 31.] + +_Cebus._[675]—Form rather robust; limbs moderate; fur not woolly; pollex +well developed; tail not naked beneath distally. + +This, the typical, genus includes the Sapajous or Capuchins (Fig. +343), which are so commonly seen in this country in captivity, being +the favourite Monkeys of itinerant musicians. They are smaller and +stouter in build than the Spider Monkeys, from which they are readily +distinguished by the well-developed pollex, and the absence of a naked +under surface to the extremity of the tail. At least twenty species +have been described (_C. fatuellus_, _C. lunatus_, _C. capucinus_, _C. +albifrons_, _C. hypoleucus_, etc.), but it is probable that some of these +are not entitled to stand, since there is a large amount of individual +variation. Fossil remains of species of _Cebus_ have been described from +the Pleistocene cavern-deposits of Brazil. + +[Illustration: FIG. 343.—The White-cheeked Sapajou (_Cebus lunatus_). +From _Proc. Zool. Soc._ 1865, pl. 45.] + + +_Family_ CERCOPITHECIDÆ. + +Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃; total 32. Crowns of molars +elongated antero-posteriorly, with the tubercles forming a pair of +imperfect transverse ridges, and the last lower molar usually with a hind +talon. A bony external auditory meatus. A narrow internarial septum. Tail +non-prehensile. Ischiatic callosities present. Cheek-pouches present or +absent. Pollex, when present, opposable. Pelvic limbs never much longer +than pectoral. Sternum narrow. Cæcum without vermiform appendage. + +This family includes all the Old World Apes, with the exception of the +_Simiidæ_, and may be divided into the subfamilies _Cercopithecinæ_ and +_Semnopithecinæ_. + +Subfamily =Cercopithecinæ=.—Pelvic and pectoral limbs approximately +equal; tail variable; cheek-pouches present; stomach simple. + +This subfamily comprises, the African Baboons, the common Indian +Monkeys constituting the genus _Macacus_, together with the African +_Cercopithecus_ and _Cercocebus_ and a few allied types. + +_Cynocephalus._[676]—Muzzle much elongated (Fig. 344), with the nostrils +terminal; ischial callosities very large; tail more or less short; muzzle +swollen by enlargement of the maxillæ. Now confined to Africa and Arabia. + +[Illustration: FIG. 344.—Skeleton of the Chacma Baboon (_Cynocephalus +porcarius_). From De Blainville.] + +This genus comprises the typical Baboons, and we may select the +well-known Mandrill (_C. maimon_), of tropical West Africa, as a good +illustrative example. It may be mentioned in passing that the name +Mandrill appears to have been first introduced into English literature by +William Smith in his _New Voyage to Guinea_, published in 1744, wherein +he mentions among the animals of Sierra Leone one “called by the white +men in this country Mandrill,” but adds, “why it is so called I know +not.”[677] Smith gives sufficiently accurate details to show that his +animal is not that now called Mandrill, but the Chimpanzee. Buffon, +however, while quoting Smith’s description, transferred the name to the +very different species now under consideration, and to that it has been +attached ever since. + +The Baboons generally are distinguished from most other Monkeys by +the comparative equality of the length of their limbs, which with the +structure of the vertebral column adapts them rather for quadrupedal +progression on the ground than for climbing among the branches of trees; +and some of them, like the South African Chacma (_C. porcarius_), of +which the skeleton is shown in Fig. 344, live habitually among rocks, +and are much less completely frugivorous than other Apes. They are also +remarkable for the great size of their face and jaws as compared with the +part of the skull which encloses the brain. The Mandrill, in addition +to these characters, is distinguished by the heaviness of its body, +stoutness and strength of its limbs, and exceeding shortness of its tail, +which is a mere stump, not 2 inches long, and usually carried erect. It +is, moreover, remarkable for the prominence of its brow ridges, beneath +which the small and closely approximated eyes are deeply sunk; the +immense size of the canine teeth; the great development of a pair of oval +bony prominences on the maxillary bones in front of the orbits, rising on +each side of the median line of the face, and covered by a longitudinally +ribbed naked skin; and more especially for the extraordinarily vivid +colouring of some parts of the skin. The body generally is covered with a +full soft coating of hair of a light olive-brown above and silvery-gray +beneath, and the chin is furnished underneath with a small pointed +yellow beard. The hair of the forehead and temples is directed upwards +so as to meet in a point on the crown, which gives the head a triangular +appearance. The ears are naked and of a bluish-black colour. The hands +and feet are naked and black. A large space around the greatly developed +ischial callosities, as well as the upper part of the insides of the +thighs, are naked and of a crimson colour, shading off on the sides to +lilac or blue, which, depending not upon pigment but upon injection of +the superficial blood-vessels, varies in intensity according to the +condition of the animal—increasing under excitement, fading during +sickness, and disappearing after death. But it is in the face that the +most remarkable disposition of vivid hues occur, more resembling those +of a brilliantly coloured flower than what might be expected in the +cutaneous covering of a mammal. The cheek-prominences are of an intense +blue, the effect of which is heightened by deeply sunk longitudinal +furrows of a darker tint, while the central line and termination of the +nose are a bright scarlet. Notwithstanding the beauty of these colours +in themselves, the whole combination, with the form and expression of +features, quite justifies Cuvier’s assertion that “il serait difficile de +se figurer un être plus hideux que le Mandrill.” + +It is only to fully adult males that this description applies. The female +is of much smaller size, and of more slender make; and, though the +general tone of the hairy parts of the body is the same, the prominences, +furrows, and colouring of the face are very much less marked. The young +males have black faces. At the age of three the blue of the cheeks begins +to appear, but it is not until they are about five, when they cut their +great canine teeth, that they acquire the characteristic red of the end +of the nose. + +[Illustration: FIG. 345.—The Yellow Baboon (_Cynocephalus babuin_). From +_Archives du Muséum_, Vol. ii. pl. 34.] + +The Mandrills, especially the old males, are remarkable for the ferocity +of their disposition, as well as for other disagreeable qualities, which +are fully described in Cuvier’s account of the animal in _La Ménagerie +du Muséum d’Histoire Naturelle_ (1801), but when young they can easily +be tamed. Like the rest of the Baboons, they appear to be rather +indiscriminate eaters, feeding upon fruit, roots, reptiles, insects, +scorpions, etc., and inhabit open rocky ground rather than forests. Not +much is known of the Mandrill’s habits in the wild state, nor of the +exact limits of its geographical distribution. The specimens brought to +Europe all come from the west coast of tropical Africa, from Guinea to +the Gaboon. + +An allied species, the Drill (_C. leucophæus_), which resembles the +Mandrill in size, general proportions, and shortness of tail, but wants +the bright colouring of the face which makes that animal so remarkable, +inhabits the same district. Other well-known species are the Yellow +Baboon (_C. babuin_), of West Africa (Fig. 345); the Arabian Baboon +(_C. hamadryas_), of Arabia and Abyssinia; and the Anubis Baboon (_C. +anubis_), of West Africa. + +It is very noteworthy from a distributional point of view, as showing +the former intimate connection between the faunas of the Oriental and +Ethiopian regions, that fossil remains of Baboons have been found in the +Pleistocene cavern-deposits of Madras, and also in the older Pliocene +beds of the Siwalik Hills in Northern India; the two species from the +latter deposits having been described as _C. subhimalayanus_ and _C. +falconeri_. + +_Theropithecus._[678]—Distinguished from _Cynocephalus_ by the nostrils +not being terminal, but situated as in _Macacus_. This genus is +represented by the Abyssinian Gelada (_T. gelada_) and the allied _T. +obscurus_. + +_Cynopithecus._[679]—The Black Ape of Celebes (_C. niger_) forms a +connecting link between the Baboons and the genus _Macacus_; the skull +differing from that of the latter in the development of longitudinal +ridges on the sides of the upper surface of the maxillæ, as in some of +the species of _Cynocephalus_. The muzzle is also more produced than in +_Macacus_. + +[Illustration: FIG. 346.—The Tibetan Macaque (_Macacus tibetanus_). From +Milne-Edwards, _Recherches des Mammifères_, pl. 34.] + +_Macacus._[680]—Muzzle considerably produced; nostrils not terminal; +cheek-pouches and ischial callosities well developed; tail long, short, +or absent; a distinct talon to the third lower molar. + +With the exception of the Barbary Ape (_M. inuus_) of Northern Africa +and Gibraltar, the Macaques are now exclusively Asiatic, one species +(Fig. 346) occurring in Tibet, and another (_M. speciosus_) being found +in Japan. All these Monkeys are of stout build, and it is chiefly by the +greater production of the muzzle, the larger ischiatic callosities, and +the frequent shortness of the tail that they are distinguished from the +under-mentioned African genera. The transition from the longer-tailed +to the short-tailed forms is so complete that the proposed generic +separation of the latter as _Innus_ is impracticable. In _M. innus_ the +tail is wanting; in _M. tibetanus_ (Fig. 346) and _M. nemestrinus_ of +Tenasserim it is short; in the common Bengal Monkey (_M. rhesus_) it is +about one-half the length of the head and body, while in _M. cynomolgus_ +and its allies it is still longer. In the Indian Lion-tailed Monkey (_M. +silenus_) it is tufted at the end. + +The following summary of the habits of the Macaques is taken from Mr. W. +T. Blanford’s _Mammals of British India_: “The species of the present +genus resemble each other in their habits; they are found in flocks, +often of considerable size, and generally composed of individuals +of both sexes and of all ages. They are active animals, though less +rapid in their movements, whether on trees or on the ground than the +_Semnopitheci_. Their food is varied, most of the species, if not all, +eating insects as well as seeds, fruits, etc., and one kind feeding +partly on crustacea. They have occasionally been known to devour lizards, +and, it is said, frogs also. All have the habit of cramming food into +their cheek-pouches for mastication at leisure—a practice that must be +familiar to any one who has fed monkeys in confinement. The voice and +gestures of all the species are similar, and differ entirely from those +of both the Gibbons and _Semnopitheci_.... The majority of the species +are very docile when young. They thrive well, and several of them have +bred in confinement. The period of gestation is almost seven months, only +a single young one, as a rule, being produced at a birth. They become +adult at the age of four or five years, but breed earlier.” + +The Common Indian _M. rhesus_ is found in the Himalaya at an elevation of +over 8000 feet. + +Fossil remains of _Macacus_ are found in India in the Pleistocene of +Madras and the Pliocene of the Punjab; and they also occur in the +Pliocene of France and Italy, those from the latter deposits having been +incorrectly separated as _Aulaxinuus_. Part of the jaw of a Monkey from +the Pleistocene of Essex has been described as _Macacus pliocenus_, and +is very interesting as showing the presence of Apes in Europe at that +late period. + +_Cercocebus._[681]—An African genus agreeing with _Macacus_ in the +presence of a hind talon to the third lower molar, but with the other +characters of _Cercopithecus_. The species of this genus are known as +Mangabeys, or White-eyelid Monkeys, and include _C. collaris_, _C. +fuliginosus_, _C. æthiops_, and _C. albigena_; all being from West Africa. + +_Cercopithecus._[682]—Muzzle more or less short; ischial callosities +moderate; tail long; no talon to third lower molar. Build more slender +than in _Macacus_. Confined to Africa. + +The members of this and the last genus include those Monkeys which in +their comparative slender build and length of tail make the nearest +approach to the next subfamily. There are numerous species, among which +the Green Monkey (_C. cullitrichus_), the Grivet (_C. griseo-viridis_), +the Vervet (_C. lalandi_), the Pluto Monkey (_C. pluto_, Fig. 347). The +Patas (_C. ruber_), the Diana Monkey (_C. diana_), and the Mona Monkey +(_C. mona_) are well-known types. + +Subfamily =Semnopithecinæ=.[683]—Pelvic limbs longer than the pectoral, +tail very long; no cheek-pouches; stomach sacculated. Build slender. + +[Illustration: FIG. 347.—The Pluto Monkey (_Cercopithecus pluto_). From +Gray, _Proc. Zool. Soc._ 1848, p. 57.] + +This subfamily is represented by three genera, of which one is African +and two are Asiatic. Mr. W. T. Blanford, in his _Mammals of British +India_, observes that “the members of this subfamily are readily +distinguished by their slender form, and by the absence of cheek-pouches. +They are more purely herbivorous than the Macaque Monkeys, and a +considerable portion of their food consists of leaves and young shoots. +In consequence probably of the nature of their food, these Monkeys are +more delicate than the species of _Macacus_, and are thus less easily +kept in captivity. They are consequently far less well represented in +European museums, and have been less studied by European naturalists. +Very little is known of their general life-history or of their feeding +habits.” + +Their digestive organs are much modified, the stomach attaining an +extraordinary complexity, which may be described as follows. An ordinary +stomach must be supposed to lie immensely elongated, and gradually +tapering from the cardiac end to a very prolonged, narrow, pyloric +extremity. Then two longitudinal muscular bands, corresponding in +situation to the greater and lesser curvatures of an ordinary stomach—the +former commencing just below the fundus, and the latter at the cardiac +orifice, and both proceeding towards the pylorus—are developed, so as +to pucker up the cavity into a number of pouches, exactly in the same +principle as the human colon is puckered up by its three longitudinal +bands. These pouches are largest and most strongly marked at the +œsophageal end, and becoming less and less distinct, quite cease several +inches before the pylorus is reached, the last part of the organ being +a simple smooth-walled tube. The fundus, or cardiac end of the stomach, +is formed by a single large sac, slightly constricted on its under +surface by the prolongation of the interior longitudinal band, or that +corresponding to the great curvature. The œsophagus enters into the upper +part of the left, or pyloric end of this sac, or rather at the point +of junction between it and the second (also a very large) sacculus. +Furthermore, the whole of this elongated sacculated organ is, by the +brevity, as it were, of the lesser curvature, coiled upon itself in an +irregularly spiral manner, so that when _in situ_ the pylorus comes to be +placed very near the œsophageal entrance. + +[Illustration: FIG. 348.—Lateral view of the skull and palatal aspect of +the cranium of _Semnopithecus nemæus_. (From De Blainville.)] + +_Nasalis._[684]—Skull resembling that of the _Cercopithecinæ_ in that the +lower border of the nasal bones extends considerably below the lower +border of the orbits, whereas in the other _Semnopithecinæ_ the aperture +of the nares extends upwards between the orbits. Nose produced into a +large proboscis. Other characters as in _Semnopithecus_. + +This genus includes only the Proboscis Monkey (_N. larratus_) of Borneo, +remarkable for the great prolongation of the nose in the adult. In young +animals the nose is relatively much shorter, and bent upwards after the +manner of that of _Semnopithecus roxellanæ_ (Fig. 349). + +[Illustration: FIG. 349.—_Semnopithecus roxellanæ._ (From Milne-Edwards, +_Recherches des Mammifères_, pl. 36.)] + +_Semnopithecus._[685]—Pollex small; narial aperture extending upwards +between the orbits. Now confined to Asia. + +This genus is characteristic of South-Eastern Asia from the Himalaya +southwards, the Oriental region being its headquarters. The development +of the muzzle is less than in the Macaques, and the facial angle is +higher, but it does not appear that this indicates greater intellectual +capacity. The outlying _S. roxellanæ_[686] (Fig. 349), of the highlands +of Eastern Tibet and Kansu, is remarkable for the peculiar upturned nose, +in which respect, as already mentioned, it recalls the young of _Nasalis +larvatus_. The genus is represented in India and Burma by no less than +fourteen species, of which the common Indian Langur, or Hanuman Monkey +(_S. entellus_) and the larger Himalayan Langur (_S. schistaceus_) are +two of the best known. In the former the length of the head and body is +about 24, and that of the tail 38 inches in adult males. This monkey, +owing to the veneration in which it is held by the Hindus, is a great +pest in many parts of India, frequently pilfering grain from the shops +in the native bazaars. According to Mr. Blanford, it “is usually found +in smaller or larger communities, composed of individuals of both sexes +and of all ages, the youngest clinging to their mothers and being carried +by them, especially when alarmed. An old male is occasionally found +solitary, as with so many other mammals.... Apart from villages, the +high trees on the banks of streams or of tanks, and, in parts of Central +India, rocky hills are the favourite haunts of these monkeys. Whether +on trees, on rocks, or on the ground, they are exceedingly active.” The +closely allied _S. schistaceus_ attains a larger average size, full grown +males attaining a length of 30 inches, the tail measuring 36 inches. +In the spring and winter this species may be observed in the Kashmir +Himalaya leaping among the snow-laden trees of the forest. In a fossil +state _Semnopithecus_ occurs in the Pleistocene and Pliocene of India, +and it has also been recorded from the Pliocene of France and Italy. + +_Colobus._[687]—This African genus differs from _Semnopithecus_ in that +the pollex is absent or reduced to a small tubercle, which may or may not +carry a nail. About eleven species have been described, some of which are +remarkable for the beautiful mantle of long silky hair which hangs down +from each side of the body, and for their tufted tails. In _C. guereza_ +from Abyssinia these are white, and the rest of the body and limbs black. +Others (as _C. satanas_) are entirely black. The skins of the long-haired +species are largely imported into Europe for the manufacture of ladies’ +muffs, etc. + +_Extinct Genera._—Certain types of Apes from the European Tertiaries +indicate genera referable to the _Cercopithecidæ_, but distinct from +any of those now living. Of these _Mesopithecus_,[688] from the Lower +Pliocene Pikermi beds of Attica, is known by almost complete skeletons, +and resembles _Macacus_ in the shortness and stoutness of the limbs, but +agrees with _Semnopithecus_ in the characters of the skull and teeth. An +allied Monkey from the Lower Pliocene of Perpignan, in France, differs +from _Mesopithecus pentelici_ by its superior size, proportionately more +produced muzzle, and larger hind talon to the last lower molar; it has +been described under the name of _Dolichopithecus_.[689] + +The genus _Oreopithecus_[690] was founded upon the remains of an Ape +from the Middle Miocene of Monte Bamboli, in Tuscany, of somewhat larger +size than a Gibbon, and apparently presenting characters connecting +the _Cercopithecidæ_ and _Simiidæ_. According to Dr. Ristori,[691] it +resembles the former, especially _Cynocephalus_ and _Semnopithecus_, in +the long dental series and the elongation of the last molars; but in the +shortness of the face, rounding of the chin, and the diagonal arrangement +of the molar tubercles, it approximates to the _Simiidæ_, of which it may +have been an ancestral type. + + +_Family_ SIMIIDÆ. + +Crowns of molars relatively wide, with the angles more or less rounded +off, the tubercles not forming transverse ridges, and the last lower +molar without a hind talon. No tail. No cheek-pouches. Ischiatic +callosities, if present, small. Pectoral limbs much longer than pelvic. +Sternum broad. Cæcum with vermiform appendage. Centrale of carpus +sometimes absent. Other characters as in _Cercopithecidæ_. + +This family contains the true Anthropoid Old World Apes, namely the +Gibbons, Orangs, Chimpanzees, and Gorillas, which are the most highly +organised of all the Apes, and thus make the nearest approach to Man. + +_Hylobates._[692]—Skull not produced at the vertex; body and limbs +slender, the pectoral limbs being so elongated that the hands reach +the ground when walking upright; hallux well developed; a centrale in +the carpus; and small ischiatic callosities. Size smaller than in the +following genera, the height of the largest species (_H. syndactylus_) +not much exceeding 3 feet. Now confined to Asia. + +The Gibbons, or Long-armed Apes (Figs. 350, 351), are readily +distinguished from the remaining members of the family by the characters +given above, as well as by the circumstance that they are the only Apes +which habitually walk in an upright position. It is in these animals +that we meet with the last traces of the ischial callosities so largely +developed in the _Cercopithecidæ_. The species are now restricted to +South-Eastern Asia, being especially abundant in the Malay Archipelago +and adjacent regions. + +The largest species is the Sumatran Siamang (_H. syndactylus_), which +attains a height of 3 feet, and has been generically separated by some +writers as _Siamanga_. It is remarkable as having a better developed +chin and wider sternum than any other Ape, and differs from the other +members of the genus by the circumstance that the second and third digits +of the pes are united by skin as far as their last joints. Exclusive of +this species, the Gibbons differ but little from one another in size and +general conformation, and since the colour of individuals undoubtedly +referable to a single species is remarkably variable, there is much +uncertainty about the number of species, and much confusion in the +nomenclature. Among well-marked species we may mention the Hoolock (_H. +hoolock_), ranging from the South of Assam through Sylhet and Cachar +to the Irawadi Valley near Bhamo, the White-handed Gibbon (_H. lar_, +Fig. 350), which is found in Tenasserim and throughout Malayana, the +Dun-coloured Gibbon (_H. entelloides_, Fig. 351) of Malayana, and the +Tufted Gibbon (_H. pileatus_) of Siam and Cambogia. + +[Illustration: FIG. 350.—The White-handed Gibbon (_Hylobates lar_). From +Blanford, _Mammals of British India_, p. 8.] + +The following account of the habits of the Gibbons is taken from Mr. +W. T. Blanford’s _Mammals of British India_. “Gibbons are thoroughly +arboreal, and Hoolocks are almost, if not entirely, confined to +hill-forest. They move chiefly by means of their long arms, by which +they swing themselves for prodigious distances from branch to branch +and from tree to tree. They descend hillsides at a surprising pace, +their descent being accomplished by grasping bamboos or branches that +bend beneath their weight, and allow them to drop until they can seize +the ends of other bamboos or branches lower on the slope, and take +another mighty swing downwards. They also ascend with great rapidity, +swinging themselves from tree to tree. When walking on the ground the +Hoolock rests on its hind feet alone, with the sole flat on the ground, +and the great toe widely separated from the other digits. The arms are +usually held upwards, sometimes horizontally, their great length giving +the animal a very peculiar aspect. Gibbons walk rather quickly, with a +waddling gait, and can easily be overtaken by men when on the ground. The +food of these Apes consists of fruit, leaves, young shoots, spiders (of +which they are very fond), insects, birds’ eggs, and almost certainly of +young birds, if not of any birds they can capture. Anderson found that +small birds were killed and devoured by Hoolocks in confinement with a +method and eagerness that showed this prey to be the natural food of the +Apes. The Hoolock drinks with its lips, putting its head down to the +water as Monkeys do. All species of _Hylobates_ have a powerful voice, +and the common name of the Hoolock is taken from its peculiar double +call, which is repeated several times. At a distance the sound much +resembles a human voice; it is a peculiar wailing note, audible from +afar, and in the countries inhabited by these animals is one of the most +familiar forest sounds. The calls commence at daybreak, and are continued +till 9 or 10 A.M., several of the flock joining in the cry, like hounds +giving tongue. After 9 or 10 o’clock in the morning the animals feed or +rest, and remain silent throughout the middle of the day, but recommence +calling towards evening, though to a less extent than in the earlier part +of the day.” + +[Illustration: FIG. 351.—The Dun-coloured Gibbon (_Hylobates +entelloides_). From _Archiv. du Muséum_, vol. ii. pl. 29.] + +The skull of the Gibbons, although agreeing with that of other Apes in +its prognathism, presents a somewhat human appearance, and the molar +teeth are also very like diminutive human molars. In the anterior inward +inclination of the two series of cheek-teeth and the inward position +of the upper premolars the Gibbons make an approach to the human type +unknown in other Apes. + +The figure of the liver of one species of this genus is introduced to +show the general absence of lateral fissures and the small size of the +caudate lobe (_c_) characteristic of the liver of all the _Simiidæ_, +except _Gorilla_ (see p. 706), as well as that of Man. Another specimen +of the liver of the same species showed scarcely any trace of a caudate +lobe. + +[Illustration: FIG. 352.—Under surface of the liver of _Hylobates lar._ +_u_, Umbilical fissure; _p_, portal fissure; _vc_, vena cava; _l_, left +lobe; _r_, right lobe; _s_, Spigelian lobe; _c_, caudate lobe; _g_, +gall-bladder.] + +A fossil Ape from the Middle Miocene of France, originally described as +_Pliopithecus_, indicates an extinct Gibbon which does not appear to be +generically separable from _Hylobates_. + +_Simia._[693]—Skull (Fig. 353) produced at the vertex; body and limbs +massive; the pectoral limbs reaching to the ankle; a centrale in the +carpus; hallux very small; sixteen dorso-lumbar vertebræ, and twelve +pairs of ribs; no ischiatic callosities. Oriental. + +[Illustration: FIG. 353.—Side view of the skull of adult Orang (_Simia +satyrus_). From _Trans. Zool. Soc._ vol. i. pl. 53.] + +This genus includes the large red-haired Apes from Sumatra and Borneo +commonly known as Orangs, or Orang-Utans,[694] of which there is probably +only a single species (_S. satyrus_). These animals inhabit the swampy +forests near the coasts; and the males attain a height of about 4 feet 4 +inches. The body is very bulky and the legs exceedingly short, but the +arms are very long, reaching in the erect posture down to the ankles. +The Orang walks resting on the knuckles of the hands and the outer sides +of the feet, with the soles of the latter turned mainly inwards, as in +Fig. 354. Its movements appear to be slow and deliberate, and in those +specimens which have been kept in captivity in this country the demeanour +is languid and melancholy, although this is far from being the case with +those shown in the more congenial climate of the Zoological Gardens at +Calcutta. The habits of these animals are arboreal, and they build a kind +of shelter or nest of boughs and leaves; their food appears to consist +mainly of fruits, and is exclusively of a vegetable nature. The whole +of the body is clothed with long hair of a reddish-brown colour, and +full-grown males have a well developed beard; the males not unfrequently +also develop a large warty protuberance, formed of fibro-cellular tissue, +on either side of the face. The hands are long, and are characterised +by the small size of the pollex, which does not reach to the end of +the metacarpal of the index finger. The feet have a similar structure, +the hallux only reaching to the middle of the proximal phalange of the +adjacent toe, and being often destitute not only of a nail, but likewise +of the terminal phalange. The presence of a centrale in the carpus is a +feature in which _Simia_ agrees with _Hylobates_ and the lower Apes, and +differs from the two following genera and Man. With very rare exceptions +the number of dorso-lumbar vertebræ is sixteen, of which twelve carry +ribs, and therefore belong to the dorsal series, while the remaining +four are lumbar. The distinction between the last lumbar and the first +sacral vertebræ is clearly marked in young skeletons by the additional +pleurapophysial ossifications (sacral ribs) in the transverse processes +of the latter. Thus though _Simia_ presents a closer resemblance to +Man than does _Anthropopithecus_ in the number of ribs, it differs +in the more important characters of that of the whole series of +trunk-vertebræ.[695] The hemispheres of the brain are much convoluted; +the whole brain being more human-like than in any other Ape. The larynx +is remarkable for having a prolongation from each ventricle, which in the +adult become of enormous dimensions, and unite in front of the trachea to +form one large sac extending downwards between the muscles to the axilla. + +[Illustration: FIG. 354.—The Orang-Utan (_Simia satyrus_). From Mr. +Wolf’s sketch at the Zoological Gardens.] + +The skull of the Orang (Fig. 353) is characterised by its highly vaulted +cranial portion, which is comparatively short (brachycephalic). The +sagittal crest is well developed on the vertex, and has a highly convex +contour; the superciliary ridges are but moderately developed, and do not +stand out in the prominent manner so characteristic of the Gorilla. The +aperture of the nares in the skull is more pear-shaped than in the two +following genera. + +The canines of the male Orang attain a great development; and the molars +are characterised by the complex structure of their cusps and the +numerous rugosities on the crown surface. The outer border of the upper +premolars is placed in the same line as that of the molars. + +The broken canine tooth of a large Anthropoid Ape from the Lower Pliocene +of the Siwalik Hills probably indicates the existence at that period of a +species of _Simia_ in Northern India. + +_Gorilla._[696]—Skull not produced at the vertex; body and limbs massive, +the pectoral limb not reaching below the middle of the lower leg (Fig. +355); no centrale in the carpus: hallux well developed; seventeen +dorso-lumbar vertebræ, of which thirteen carry ribs; no ischiatic +callosities. Male much larger than female, and with very strongly marked +cranial ridges, which are wanting in the latter. Mandibular symphysis +long. Ethiopian. + +The well-known Gorilla (Fig. 356), of which there seems to be only one +species (_G. savagei_), is found in Western Equatorial Africa, chiefly or +entirely in the district enclosed by the Cameroon and Congo rivers. It +is the largest of all the Apes, its bulk considerably exceeding that of +man, although from the shortness of the legs it appears never to attain a +greater height than 5½ feet. The first introduction of this animal to the +notice of zoologists was made in 1847 by Dr. Thomas Savage, but it was +not fully known till many years later. + +[Illustration: FIG. 355.—Skeleton of the Gorilla. (From De Blainville.)] + +The skin of the Gorilla is entirely black, the hair being blackish, but +turning more or less gray in old individuals. The arms reach down as far +as the middle of the lower leg; while the pollex extends only a short +distance beyond the base of the first phalange of the index finger, +and the hallux reaches nearly as far as the distal extremity of the +corresponding digit of the foot. The digits of both the hand and foot are +united together by integument as far as the distal extremities of the +first phalanges. The larynx has very capacious air-sacs, which meet in +front of the trachea and communicate with the ventricles; and in advanced +age these sacs may extend to the axilla. The ears are relatively small. +The skull is of an elongated or dolichocephalic type; that of the adult +male being characterised by the enormous development of the supraorbital +ridges, which form a kind of penthouse over the eyes, and contribute to +the peculiarly ferocious appearance of the animal. The sagittal crest is +also very large. The canine teeth of the male are very large, and are +inclined outwards in both jaws. In the cheek-teeth the upper premolars +are of considerable antero-posterior extent, with their outer border +placed in the same line as that of the molars; and the third upper molar +is larger than either of the others. + +[Illustration: FIG. 356.—The Gorilla (_Gorilla savagei_). From _Trans. +Zool. Soc._ vol. iv. pl. 43.] + +The posterior cervical vertebræ are characterised by the great height +of their neural spines, which thus form a strong basis for the powerful +cervical muscles supporting the massive skull. In some instances +the fourth lumbar vertebra becomes ankylosed to the sacrum, as is +occasionally found to be the case in some of the lower human races. + +In the absence of a centrale to the carpus, and also in the number of +the dorso-lumbar vertebræ, the present and following genus resemble man; +although they both differ in having thirteen in place of twelve pairs of +ribs. + +The brain of the Gorilla, according to Dr. Hartmann, resembles that +of the Orang in the complexity of its convolutions, and is thereby +distinguished from that of the Chimpanzee. In form it is of the long oval +characteristic of Man; the brain of the Chimpanzee and Orang being more +rounded. + +Gorillas live in family parties in the depths of the dense forests of +Western Equatorial Africa, seeking their food during the day, while at +night it is said that the female and young ascend a tree at the foot of +which the male sleeps. They walk with the backs of their closed hands and +the flat soles of the feet placed on the ground. Although there has been +much exaggeration on this point, it appears certain that the male Gorilla +is an extremely ferocious and dangerous animal when brought to bay, but +the statements as to its making unprovoked assaults on men do not appear +authentic. They utter deep guttural sounds, which on some occasions may +be described as grunts and at others as a roar. + +_Anthropopithecus._[697]—One of the most important differences of this +genus from the preceding is the absence of any marked disparity between +the two sexes, either in the size or the conformation of the skull, +although the male can always be distinguished by the larger size of the +canine teeth. The mandibular symphysis is also much shorter. Differences +in the characters of the teeth are described below. The genus is confined +at the present day to the Ethiopian region. + +The Chimpanzees (Fig. 357) inhabit Western and Central Equatorial +Africa; and there has been much discussion whether they should all be +included under one specific name (_A. troglodytes_), or whether there are +really two or more species. A female specimen now living in the London +Zoological Gardens, characterised among other distinctive features by the +nearly bald head, clearly indicates, however, a second species, which +probably corresponds to the imperfectly defined _A. calvus_ of Du Chaillu. + +The region inhabited by the Chimpanzees extends from the Gambia to the +Benguela, reaching as far inland as 28° E. long. The Common Chimpanzee is +a smaller animal than the Gorilla, its height not exceeding 5 feet. In +colour it is darker than the latter, and the ears are relatively larger. +In the upright position the arms reach only a short distance below the +knee, in which respect the Chimpanzee is more human-like than any of the +other Apes. The face is furnished with distinct whiskers, eyebrows, and +eyelashes. The pollex reaches nearly or quite to the base of the first +phalange of the index finger, and the hallux to the base of the second +phalange of the corresponding digit of the foot. The laryngeal sacs are +as largely developed as in the Gorilla. + +[Illustration: FIG. 357.—The Chimpanzee (_Anthropopithecus troglodytes_). +From Mr. Wolf’s drawing of a young individual in the Zoological Society’s +Gardens.] + +Although the skull of the Chimpanzee has distinct superciliary ridges, +yet the high bony crests of the calvarium of the male Gorilla are +wanting, and the whole coronal region of the skull is more rounded and +far less rugged. + +The canine teeth of the male Chimpanzee are relatively much smaller than +in the Gorilla and Orang. The upper molars are characterised by the +third one being smaller than either of the other two, as well as by the +presence of an indistinct cingulum on their inner surfaces. The upper +premolars differ from those of the other genera of the family by the +shortness of their antero-posterior diameter, and also by the larger +size of their external as compared with their internal cusps; while the +outer border of these teeth is placed internally to that of the upper +molars. In all these respects the teeth of the Chimpanzee make a decided +approximation to the human type. + +Many young individuals of the Chimpanzee have been brought to Europe, but +they appear to succumb sooner or later to the effects of an unsuitable +climate. All these examples show that the disposition of this Ape is +gentle, lively, and intelligent, and in all respects markedly opposite +to that of the Orang. In a wild state these Apes are essentially +forest-dwellers, and are more arboreal in their habits than the Gorilla. +They live either in families, or in small parties of several families. +Frequently at least they construct a kind of nest in the trees as a +sleeping-place; the male being said to sleep on a forked branch below the +level of this nest. In walking the Chimpanzee usually supports himself on +the backs of his closed fingers, and either on the soles of the feet or +on the closed toes. + +From a distributional point of view the discovery of a fossil Ape in the +Pliocene of the Punjab, apparently closely allied to the Chimpanzee, +is of great interest. This determination rests upon the evidence of an +imperfect palate originally described under the name of _Palæopithecus_, +but subsequently referred to the present genus. The teeth of this jaw +present all the essential characters of those of the Chimpanzee, but +the two series of cheek-teeth have a slight anterior convergence, the +premolars are shorter in the antero-posterior direction than is usually +the case in that species, and the outer incisor is relatively narrower +than in the latter. In these features the extinct _A. sivalensis_ makes a +nearer approximation to the human type than is the case with its living +congeners. + +_Dryopithecus._[698]—The extinct _Dryopithecus_ of the Middle Miocene of +France is represented by a single species of the approximate size of the +Chimpanzee, and appears to be the most generalised member of the family. +According to the recent observations of Professor Gaudry,[699] while it +resembles the Gorilla in that the two series of lower cheek-teeth diverge +anteriorly and the penultimate premolar is larger than the last of that +series, it differs in having a much longer and narrower mandibular +symphysis, and thus indicates a transition to the _Cercopithecidæ_. A +gradual transition in the form of the mandible may, indeed, be traced +from _Dryopithecus_, through _Gorilla_, to _Anthropopithecus_; the latter +having a short and wide symphysis, with the two series of cheek-teeth +slightly converging anteriorly, and the penultimate premolar being not +larger than the last. In all these specialised characters the jaw of +the Chimpanzee approximates to that of Man, in which the symphysis is +still further shortened and widened, and the anterior convergence of the +cheek-teeth so much increased as to produce a horse-shoe-like form in the +whole dental series. + + +_Family_ HOMINIDÆ. + +In the _Systema Naturæ_ of Linnæus Man was separated only generically +from the Apes, but in the next great work which exercised a widespread +influence over the progress of zoological science, the _Règne Animal_ of +Cuvier, he forms a distinct order under the name of Bimana, the Monkeys +and Lemurs being associated together as Quadrumana. This has been the +prevailing arrangement in the zoological systems of the present century, +though in the classification of Owen his position is still farther +removed from that of the Monkeys, as in it the genus _Homo_ forms one +of the four primary divisions or subclasses of the Mammalia, called +Archencephala, the Quadrumana being united with the Carnivora, Ungulata, +and others in another division called Gyrencephala. On the other hand, +the tendency of most modern systematists, for reasons which have been +fully stated by Professor Huxley,[700] is to revert towards the Linnæan +position. + +Considering solely the facts of Man’s bodily structure, it can be +clearly demonstrated that the points in which he differs from the Ape +most nearly resembling him are not of greater importance than those by +which that Ape differs from other universally acknowledged members of +the group; and therefore, in any natural system, if Man is to be made a +subject of zoological classification upon the same principles as those +applied elsewhere, he must be included in the order which comprises +the Monkeys. We say upon the same principles as are applied elsewhere, +since zoological classification has never taken into consideration +the psychological characteristics which distinguish the subjects of +its investigations, but only their tangible and physical structure, +otherwise endless confusion would result, at all events with our very +imperfect knowledge of animal psychology. The essential attributes which +distinguish Man, and give him a perfectly isolated position among living +creatures, are not to be found in his bodily structure, and should +therefore either be left entirely out of consideration, or have such +weight given to them as would remove him completely out of the region +of zoological classification. To profess to classify Man as if he were +one of the animals (as in all points of the structure and functions of +his organs he undoubtedly is), to place him in the class Mammalia, and +then to allow other considerations to influence the judgment as to the +particular position he should occupy in the class, is most illogical. + +Man, therefore, considered from a zoological point of view, must be +included in the order Primates, even if the Lemurs be removed from it, +since his structural affinities with the Monkeys are far closer than +are those of the so-called “Half-Apes.” We may, without treading upon +debatable ground, go farther, and say that the differences between Man +and the Anthropoid Apes are really not so marked as those which separate +the latter from the American Monkeys. This being admitted, perhaps the +best exposition relating to the present condition of the order will be +to regard Man as representing a fifth family of the Anthropoidea, which +should be known as the _Hominidæ_. In thus ranking Man as one of the five +principal families or sections of the suborder it should, however, be +observed that this course does not in the least degree imply that such +families are precisely equivalent to one another, or that the intervals +by which they are separated are of equal importance; all that we commit +ourselves to being that they are five perfectly distinct groups, all +branches from a common stem, and in the present state of nature not +united by any intermediate types. + +The distinctions between the _Hominidæ_ and _Simiidæ_ are chiefly +relative, being greater size of brain and of brain-case as compared +with the facial portion of the skull, smaller development of the +canine teeth of the males, complete adaptation of the structure of the +vertebral column to the vertical position, greater length of the lower +as compared with the upper extremities, and greater length of the hallux +or great toe, with almost complete absence of the power of bringing it +in opposition to the other four toes. The last feature together with the +small size of the canine teeth are perhaps the most marked and easily +defined distinctions that can be drawn between the two groups. + +Man is universally admitted to form a single genus, _Homo_ of Linnæus, +but a question of considerable importance in treating of him from a +zoological point of view, and one which has been a subject of much +controversy, is whether all men should be considered as belonging to a +single or to several species. This question is perhaps of less importance +now than formerly, when those who maintained a plurality of species +associated with the hypothesis plurality of origin. One of the strongest +arguments against the view that the various races of Man represent more +than one species is that none of those who have maintained it have been +able to agree as to how many distinct specific modifications can be +defined, almost every number from three to twenty or more having been +advocated by different authors. If the distinguishing characters of +the so-called species had been so marked, there could not be such a +remarkable diversity of opinion upon them. Again, the two facts—(1) that, +however different the extremes of any two races may be in appearance +(and it must be admitted that, as advocated by many polygenists, the +differences are greater than many which are considered specific among +other animals), every intermediate gradation can be found through which +the one passes into the other, and (2) that all races are fertile _inter +se_—are quite conclusive in favour of considering Man as representing a +single species in the ordinary sense in which the word is now used, and +of treating of all his various modifications as varieties or races. + +The great problem at the root of all zoology, the discovery of a natural +classification which shall be an expression of our knowledge of the real +relationship or consanguinity of different forms, is also applicable to +the study of the races of Man. When we can satisfactorily prove that any +two of the known groups of mankind are descended from the same common +stock, a point is gained. The more such points we have acquired the more +nearly shall we be able to picture to ourselves, not only the present, +but also the past distribution of the races of Man upon the earth, and +the mode and order in which they have been derived from one another. +But the difficulties in the way of applying zoological principles to +the classification of Man are vastly greater than in the case of most +animals. When groups of animals become so far differentiated from each +other as to represent separate species, they remain isolated; they +may break up into further subdivisions—in fact, it is only by further +subdivision that new species can be formed; but it is of the very essence +of species, as now universally understood by naturalists, that they +cannot recombine, and so give rise to new forms. With the varieties of +Man it is otherwise. They have never so far separated as to answer to +the physiological definition of species. All races, as said above, are +fertile with one another, though perhaps in different degrees. Hence new +varieties have constantly been formed, not only by the segmentation of +portions of one of the old stocks, but also by various combinations of +those already established. + +Without entering into the difficult question of the method of Man’s first +appearance upon the world, we must assume for it vast antiquity,—at all +events as measured by any historical standard. Of this there is now +ample proof. During the long time Man existed in a savage state—a time +compared to which the dawn of our historical period is as yesterday—he +was influenced by the operation of those natural laws which have +produced the variations seen in other regions of organic nature. The +first Men may very probably have been all alike; but when spread over +the face of the earth and subjected to all kinds of diverse external +conditions,—climate, food, competition with members of their own +species or with wild animals,—racial differences began slowly to be +developed through the potency of various kinds of selection acting upon +the slight variations which appeared in individuals in obedience to the +tendency planted in all living things. These differences manifested +themselves externally in the colour of the skin, the colour, quality, +and distribution of the hair, the form of the head and features, and the +proportions of the limbs, as well as in the general stature. + +Geographical position must have been one of the main elements in +determining the formation and permanence of races. Groups of Men isolated +from their fellows for long periods, such as those living on small +islands, to which their ancestors may have been accidentally drifted, +would naturally, in course of time, develop a new type of features, of +skull, of complexion, or hair. A slight set in one direction in any of +these characters would constantly tend to intensify itself, and so new +races would be formed. In the same way different intellectual or moral +qualities would be gradually developed or transmitted in different groups +of Men. The longer a race thus formed remained isolated the more strongly +impressed and the more permanent would its characteristics become, and +less liable to be changed or lost when the surrounding circumstances +were altered or under a moderate amount of intermixture from other +races—the more “true,” in fact, would it be. On the other hand, on large +continental tracts, where no mountain ranges or other natural barriers +form obstacles to free intercourse between tribe and tribe, there would +always be a tendency towards uniformity, from the amalgamation of races +brought into close relation by war or by commerce. Smaller or feebler +races would be destroyed or absorbed by others impelled by superabundant +population or other causes to spread beyond their original limits; or +sometimes the conquering race would itself disappear by absorption into +the conquered. + +Thus for untold ages the history of Man has presented a shifting +kaleidoscopic scene: new races gradually becoming differentiated out of +the old elements, and, after dwelling a while upon the earth, becoming +either suddenly annihilated or gradually merged into new combinations; +a constant destruction and reconstruction; a constant tendency to +separation and differentiation, and a tendency to combine again into +a common uniformity—the two tendencies acting against and modifying +each other. The history of these processes in former times, except in +so far as they may be inferred from the present state of things, is +a difficult study, owing to the scarcity of evidence. If we had any +approach to a complete palæontological record, the history of Man could +be reconstructed; but nothing of the kind is forthcoming. Evidence of +the anatomical characters of Man as he lived on the earth during the +time when the most striking racial characteristics were being developed, +during the long ante-historic period in which the Negro, the Mongolian, +and the Caucasian were being gradually fashioned into their respective +types, is entirely wanting, or if any exists it is at present safely +buried in the earth, perhaps to be revealed at some unexpected time and +in some unforeseen manner. Even the materials from which a history of +the modifications of the human species as known to our generation must +be constructed are rapidly passing away, since the age in which we live +is an age in which, in a far greater degree than any previous one, the +destruction of races, both by annihilation and absorption, is going +on. Owing to the rapid extension of maritime discovery and commerce, +changes such as have never been witnessed before are now taking place +in the ethnology of the world—changes especially affecting the island +populations among which, more than elsewhere, the solution of many of +those problems may be looked for. The subject is, however, attracting the +attention of observers of all countries to a greater degree than it ever +has before, and such progress has been made in perfecting the methods of +investigation of racial characteristics that we are beginning to learn +what lines of research are profitable and what are barren, so that we +may hope the time is not far distant when we may get some clear insight +into the knowledge of the natural classification and relationships of the +races of Man. + +The following is a brief summary of the principal results which appear to +have been attained up to the present time by the study of this somewhat +difficult subject.[701] + +The most ordinary observation is sufficient to demonstrate the fact +that certain groups of men are strongly marked from others by definite +characters common to all members of the group, and transmitted regularly +to their descendants by the laws of inheritance. Thus the Chinaman +and the Negro, the native of Patagonia and the Andaman Islander, are +as structurally distinct from each other as are many of the so-called +species of any natural group of animals. Indeed, it may be said with +truth that their differences are even greater than those which mark the +groups called genera by many naturalists of the present day. Nevertheless +the difficulty of parcelling out all the individuals composing the +human species into certain definite groups, and of saying of each man +that he belongs to one or other of such groups, is insuperable. No such +classification has ever been, or, indeed, can ever be obtained. There +is not one of the most characteristic and most extreme forms, like +those just named, from which transitions cannot be traced by almost +imperceptible gradations to any of the other equally characteristic +and equally extreme forms. Indeed, a large proportion of mankind is +made up, not of extreme or typical, but of more or less generalised +or intermediate forms, the relative numbers of which are continually +increasing, as the long-existing isolation of nations and races breaks +down under the ever-extending intercommunication characteristic of the +period in which we live. + +The difficulties of framing a natural classification of Man, or one +really representing the relationship of the various minor groups to each +other, are well exemplified by a study of the numerous attempts which +have been made from the time of Linnæus and Blumenbach onwards. Even in +the first step of establishing certain primary groups of equivalent rank +there has been no accord. Thus four primitive types were sketched out by +Linnæus—the European, Asiatic, African, and American. These were expanded +into five by Blumenbach by the addition of the Malay,[702] and reduced by +Cuvier to three by the suppression of the last two. Many later writers +have largely increased the number of these so-called primary divisions, +but the conclusion, so often arrived at by various anthropologists, and +so often abandoned for some more complex system, that the primitive +man, whatever he may have been, has in the course of ages divaricated +into three extreme types, represented by the Caucasian of Europe, the +Mongolian of Asia, and the Ethiopian of Africa, and that all existing +individuals of the species can be ranged around these types, or somewhere +or other between them, seems, on the whole, to give the clearest view +of the facts of the case. Large numbers are doubtless the descendants +of direct crosses in varying proportions between well-established +extreme forms; for, notwithstanding opposite views formerly held by some +authors on this subject, there is now abundant evidence of the wholesale +production of new races in this way. Others may be the descendants of +the primitive stock before the strongly marked existing distinctions had +taken place, and therefore present, though from a different cause from +the last, equally generalised characters. In these cases it can only be +by most carefully examining and balancing all characters, however minute, +and finding out in what direction the preponderance lies, that a place +can be assigned to them. It cannot be too often insisted on that the +various groups of mankind, owing to their probable unity of origin, the +great variability of individuals, and the possibility of all degrees of +intermixture of races at remote or recent periods of the history of the +species, have so much in common that it is extremely difficult to find +distinctive characters capable of strict definition by which they may be +differentiated. It is more by the preponderance of certain characters +in a large number of members of a group, than by the exclusive or even +constant possession of these characters in each of its members, that the +group as a whole must be characterised. + +Bearing these principles in mind, we may endeavour to formulate, as far +as they have as yet been worked out, the distinctive features of the +typical members of each of the three great divisions, and then show into +what subordinate groups each of them seems to be divided. + +We begin with the Ethiopian, Negroid, or Melanian, or “black” type. It +is characterised by a dark, often nearly black, complexion; black hair, +of a kind called “frizzly” or, incorrectly, “woolly,” _i.e._ each hair +is closely rolled up on itself, a condition always associated with a +more or less flattened or elliptical transverse section; a moderate +or scanty development of beard, an almost invariably dolichocephalic +skull; small and moderately retreating jugal bones (mesopic face); a +very broad and flat nose, platyrhine in the skeleton; moderate or low +orbits; prominent eyes; thick, everted lips; prognathous jaws; large +teeth (macrodont); a narrow pelvis (index in the male 90 to 100); a +long forearm (humero-radial index 80); and certain other proportions of +the body and limbs which are being gradually worked out, and reduced to +numerical expression as material for so doing accumulates. + +The most characteristic examples of the second great type, the Mongolian +or Xanthous, or “yellow,” have a yellow or brownish complexion; black +coarse straight hair, without any tendency to curl, and nearly round +in section; on all other parts of the surface except the scalp scanty +and late in appearing; a skull of variable form, mostly mesocephalic +(though extremes both of dolichocephalism and brachycephalism are found +in certain groups of this type); a broad and flat face, with prominent, +anteriorly-projecting jugal bones (platyopic face); nose small, mesorhine +or leptorhine; orbits high and round, with very little development of +glabella or supraciliary ridges; eyes sunken, and with the aperture +between the lids narrow; in the most typical members of the group with a +vertical fold of skin over the inner canthus, and with the outer angle +slightly elevated; jaws mesognathous; teeth of moderate size (mesodont). +The proportions of the limbs and form of the pelvis have yet to be worked +out, the results at present obtained showing great diversity among +different individuals of what appear to be well-marked races of the +group, but this is perhaps due to the insufficient number of individuals +as yet examined with accuracy. + +The last type, which, for want of a better name, we must still call by +the misleading one that has the priority, Caucasian, or “white,” has +usually a light-complexioned skin (although in some, in so far aberrant +cases, it is as dark as in the Negroes); hair fair or black, soft, +straight, or wavy, in section intermediate between the flattened and +cylindrical form; beard fully developed; form of cranium variable, mostly +mesocephalic; jugal bones retreating; face narrow and projecting in +the middle line (pro-opic); orbits moderate; nose narrow and prominent +(leptorhine); jaws orthognathous; teeth small (microdont); pelvis +broad (pelvic index of male 80); forearm short, relatively to humerus +(humero-radial index 74). + +In endeavouring to subdivide into minor groups the numerous and +variously-modified individuals which cluster around one or other of +these great types—a process quite necessary for many practical or +descriptive purposes—the distinctions afforded by the study of physical +characters are often so slight that it becomes necessary to take other +considerations into account, among which geographical distribution and +language hold an important place. + +I. The Ethiopian or Negroid races may be primarily arranged as follows:— + +A. African or Typical Negroes.—Inhabitants of all the central portion +of the African continent, from the Atlantic on the west to the Indian +Ocean on the east, greatly mixed all along their northern frontier with +Hamitic and Semitic Melanochroi, a mixture which, taking place in various +proportions and under varied conditions, has given rise to many of the +numerous races and tribes inhabiting the Sudan. + +A branch of the African Negroes are the Bantu—distinguished chiefly, +if not entirely, by the structure of their language. Physically +indistinguishable from the other negroes with whom they come in contact +in the Equatorial regions of Africa, the Southern Bantu, or Kaffirs, +as they are generally called, show a marked modification of type, +being lighter in colour, having a larger cranial capacity, less marked +prognathism, and smaller teeth. Some of these changes are probably due to +crossing with other races. + +B. The Negrillos—diminutive sub-brachycephalic tribes, inhabiting the +dense forests of Central and Western Equatorial Africa—represent a +distinct section of the Negro race. They form the only exceptions to the +general dolichocephaly of the African branch of the Negroid division, and +when found in a pure state are the smallest of all known human races, +averaging scarcely more than 4 feet in height. The colour of their skin +is yellowish rather than black. + +C. The Bushmen (Bosjesmen, men of the woods, of the Dutch colonists of +South Africa) constitute a very distinct modification of the Negro type. +The hair shows the extreme of the frizzly character; being shorter and +less abundant than that of the ordinary Negro, it has the appearance of +growing in separate tufts, which coil up together into rounded balls +compared to “peppercorns.” In their yellow complexion, wide cheek-bones, +and peculiar form of the eyes they so much resemble some of the Mongolian +races that anthropologists have been inclined to trace affinities to +or admixture with them, although the character of the hair makes such +a supposition almost inadmissible. The width of the cheek-bones and +the narrowness of the forehead and chin give a lozenge shape to the +front view of the face. The forehead is prominent and straight; the +nose extremely flat and broad, more so than in any other race; the lips +prominent and thick, although the jaws are less prognathous than in the +true Negro races. The cranium has many special characters by which it +can be easily distinguished from that of any other race. The average +height of the males is about 4 feet 8 inches. There is every reason to +believe that the Bushmen represent the earliest race of which we have +any knowledge inhabiting the southern part of the African continent, but +that long before the advent of Europeans upon the scene they had been +invaded from the north by Negro tribes, who, being superior in size, +strength, and civilisation, had taken possession of the greater part of +their territories, and, mingling freely with the aborigines, had produced +the mixed race called Hottentots, who retained the culture and settled +pastoral habits of the Negroes, with many of the physical features of the +Bushmen. These in their turn, encroached upon by the Kaffirs from the +north and by Europeans from the south, are now greatly diminished, and +threatened with the same fate which will surely soon befall the scanty +remnant of the early inhabitants who still retain their primitive type. + +D. Oceanic Negroes or Melanesians.—These include the Papuans of New +Guinea and the majority of the inhabitants of the islands of the Western +Pacific, and form also a substratum of the population, greatly mixed with +other races, of regions extending far beyond the present centre of their +area of distribution. + +They are represented, in what may be called a hypertypical form, by the +extremely dolichocephalic Kai Colos, or mountaineers of the interior of +the Fiji Islands, although the coast population of the same group has +lost the distinctive characters by crossing. In many parts of New Guinea +and the great chain of islands extending eastwards and southwards ending +with New Caledonia they are found in a more or less pure condition, +especially in the interior and more inaccessible portions of the islands, +almost each of which shows special modifications of the type recognisable +in details of structure. Taken altogether, their chief physical +distinction from the African Negroes lies in the fact that the glabella +and supraorbital ridges are generally well developed in the males, +whereas in Africans this region is usually smooth and flat. The nose +also, especially in the northern part of their geographical range, New +Guinea, and the neighbouring islands, is narrower (often mesorhine) and +prominent. The cranium is generally higher and narrower. It is, however, +possible to find African and Melanesian skulls quite alike in essential +characters. + +The now extinct inhabitants of Tasmania were probably pure, but aberrant, +members of the Melanesian group, which had undergone a modification from +the original type, not by mixture with other races, but in consequence +of long isolation, during which special characters had been gradually +developed. Lying completely out of the track of all civilisation and +commerce, even of the most primitive kind, they were little liable to +be subject to the influence of any other race; and there is in fact +nothing among their characters which could be accounted for in the way +above suggested, as they were intensely, even exaggeratedly, Negroid in +the form of nose, projection of mouth, and size of teeth, typically so +in character of hair, and aberrant chiefly in the width of the skull in +the parietal region. A cross with any of the Polynesian or Malay races +sufficiently strong to produce this would, in all probability, have also +left some traces on other parts of their organisation. + +On the other hand, in many parts of the Melanesian region there +are distinct evidences of large admixture with Negrito, Malay, and +Polynesian elements in varying proportions, producing numerous physical +modifications. In many of the inhabitants of the great island of New +Guinea itself and of the islands lying around it this mixture can be +traced. In the people of Micronesia in the north and New Zealand in the +south, although the Melanesian element is present, it is completely +overlaid by the Polynesian, but there are probably few, if any, of the +islands of the Pacific in which it does not form some factor in the +composite character of the natives. + +The inhabitants of the continent of Australia have long been a puzzle to +ethnologists. Of Negroid complexion, features, and skeletal characters, +yet without the characteristic frizzly hair, their position has been +one of great difficulty to determine. They have, in fact, been a +stumbling-block in the way of every system proposed. The solution, +supported by many considerations too lengthy to enter into here, appears +to lie in the supposition that they are not a distinct race at all, that +is, not a homogeneous group formed by the gradual modification of one +of the primitive stocks, but rather a cross between two already-formed +branches of these stocks. According to this view, Australia was +originally peopled with frizzly-haired Melanesians, such as those who +still do, or did before the European invasion, dwell in the smaller +islands which surround the north, east, and southern portions of the +continent, but that a strong infusion of some other race, probably a +low form of Caucasian Melanochroi, such as that which still inhabits +the interior of the southern parts of India, has spread throughout the +land from the north-west, and produced a modification of the physical +characters, especially of the hair. This influence did not extend across +Bass’s Straits into Tasmania, where, as just said, the Melanesian element +remained in its purity. It is more strongly marked in the northern +and central parts of Australia than on many portions of the southern +and western coasts, where the lowness of type and more curly hair, +sometimes closely approaching to frizzly, show a stronger retention +of the Melanesian element. If the evidence should prove sufficiently +strong to establish this view of the origin of the Australian natives, +it will no longer be correct to speak of a primitive Australian, or even +Australoid, race or type, or look for traces of the former existence of +such a race anywhere out of their own land. Absolute proof of the origin +of any race is, however, very difficult, if not impossible, to obtain, +and there is nothing to exclude the possibility of the Australians being +mainly the direct descendants of a very primitive human type, from which +the frizzly-haired Negroes may be an offset. This character of hair is +probably a specialisation, for it seems very unlikely that it was the +attribute of the common ancestors of the human race. + +E. The fourth branch of the Negroid race consists of the diminutive +round-headed people called Negritos, still found in a pure or unmixed +state in the Andaman Islands, and forming a substratum of the population, +though now greatly mixed with invading races, especially Malays, in the +Philippines, and many of the islands of the Indo-Malayan Archipelago, +and of some parts of the southern portion of the mainland of Asia. They +also contribute to the varied population of New Guinea, where they appear +to merge into the taller, longer-headed, and longer-nosed Melanesians +proper. They show in a very marked manner some of the most striking +anatomical peculiarities of the Negro race, such as the frizzly hair, +the proportions of the limbs, especially the humero-radial index, and +the form of the pelvis; but they differ in many cranial and facial +characters, both from the African Negroes on the one hand, and the +typical Oceanic Negroes, or Melanesians, on the other, and thus form a +very distinct and well-characterised group. Wherever they are still found +they are obviously holding their own with difficulty, if not actually +disappearing, and there is much about their condition of civilisation and +the situations in which they occur to induce us to look upon them, as in +the case of the Negrillos of Central and the Bushmen of South Africa, as +the remains of a population which occupied the land before the incoming +of the present dominant races. + +II. The principal groups that can be arranged round the Mongolian type +are as follows:— + +A. The Eskimo appear to be a branch of the typical North Asiatic Mongols, +who in their wanderings northwards and eastwards across the American +continent, where they have been isolated almost as perfectly as an island +population would be, hemmed in on one side by the eternal Polar ice, +and on the other by hostile tribes of American Indians, with which they +rarely, if ever, mingled, have gradually developed characters, most of +which are strongly-expressed modifications of those seen in their allies +who still remain on the western side of Behring Strait. It has also been +shown that these special characteristics gradually increase from west to +east, and are seen in their greatest perfection in the inhabitants of +Greenland, at all events in those where no crossing with the Danes has +taken place. A typical Eskimo skull presents a combination of characters +by which it can be at once distinguished from that of any other of the +groups of mankind. Such scanty remains as have yet been discovered of the +earliest inhabitants of Europe do not present any structural affinities +to this type, and there is therefore no justification for the supposition +that they belonged to the same race, although it is not unlikely that +similar external conditions may have led them to adopt similar modes of +life. + +B. The typical Mongolian races constitute the present population of +Northern and Central Asia. They are not very distinctly, but still +conveniently for descriptive purposes, divided into a Northern and a +Southern group. + +_a._ The members of the former, Mongolo-Altaic or Sibiric group, are +united by the affinities of their language. These people, from the cradle +of their race in the great plateau of Central Asia, have at various +times poured out their hordes upon the lands lying to the west, and +thence penetrated almost to the heart of Europe. The Lapps, Finns, the +Magyars, and the Turks are each the descendants of one of these waves of +incursion, but they have for so many generations intermingled with the +peoples through whom they have passed in their migrations, or whom they +have found in the countries in which they have ultimately settled, that +their original physical characters have been completely modified. Even +the Lapps, that diminutive tribe of nomads inhabiting the most northern +parts of Europe, supposed to be of Mongolian descent, show so little of +the special attributes of that branch that it is difficult to assign them +a place in it in a classification based upon physical characters. The +Japanese are said by their language to be allied rather to the Northern +than to the following branch of the Mongolian stock. + +_b._ The southern Mongolian or Sinitic group, divided from the former +chiefly by language and habits of life, includes the greater part of the +population of China, Tibet, Burma, and Siam. + +C. The next great division of Mongoloid people is the Malay, forming the +bulk of the population of the Indo-Malayan Archipelago and (mixed with +the Negro) of Madagascar, subtypical it is true, but to which an easy +transition can be traced from the most characteristic members of the type. + +D. The brown Polynesians, Malayo-Polynesians, Mahoris, Sawaioris, or +Kanakas, as they have been variously called, seen in their greatest +purity in the Samoan, Tongan, and Eastern Polynesian Islands, are still +more modified, and possess less of the characteristic Mongolian features; +but yet it is difficult to place them anywhere else in the system. The +large infusion of the Melanesian element throughout the Pacific must +never be forgotten in accounting for the characters of the people now +inhabiting the islands—an element in many respects so diametrically +opposite to the Mongolian that it would materially alter the characters, +especially of the hair and beard, which has been with many authors a +stumbling-block to the affiliation of the Polynesian with the Mongolian +stock. This mixture is physically a fine one, and in some proportions +produces a combination, as seen, for instance, in the Maories of New +Zealand, which in all definable characters approaches quite as near, or +nearer, to the Caucasian type than to either of the stocks from which it +may be presumably derived. This resemblance has led some ethnologists +to infer a real extension of the Caucasian element at some very early +period into the Pacific Islands, and to look upon their inhabitants as +the product of a mingling of all the three great types of men. Though +this is a very plausible theory, it rests on little actual proof, +since the combination of Mongolo-Malayan and Melanesian characters in +different degrees, together with the local variations certain to arise +in communities so isolated from each other and exposed to such varied +conditions as the inhabitants of the Pacific Islands, would probably +account for all the modifications observed among them. + +E. The native population (before the changes wrought by the European +conquest) of the great continent of America, excluding the Eskimo, +present, considering the vast extent of the country they inhabit and +the great differences of climate and other surrounding conditions, a +remarkable similarity of essential characters with much diversity of +detail. + +The construction of the numerous American languages, of which as many +as twelve hundred have been distinguished, is said to point to unity of +origin, as, though widely different in many respects, they are all, or +nearly all, constructed on the same general grammatical principle—that +called _polysynthesis_—which differs from that of the languages of any +of the Old World nations. The mental characteristics of all the American +tribes have much that is in common, and the very different stages of +culture to which they had attained at the time of the conquest, as that +of the Incas and Aztecs and the hunting or fishing tribes of the north +and south, which have been quoted as evidence of diversities of race, +were not greater than those between different nations of Europe, as +Gauls and Germans on the one hand, and Greeks and Romans on the other, +in the time of Julius Cæsar. Yet all these were Aryans, and in treating +the Americans as one race it is not intended to imply that they are more +closely allied than the different Aryan peoples of Europe and Asia. The +best argument that can be used for the unity of the American race—using +the word in a broad sense—is the great difficulty of forming any natural +divisions in it founded upon physical characters. Thus there is no +difference throughout the whole continent in the important character of +the hair, this being always straight and lank, long and abundant on the +scalp, but sparse elsewhere. The colour of the skin, notwithstanding the +enormous differences of climate under which many members of the group +exist, varies but little. It is true that in the features and cranium +certain special modifications prevail in different districts, but the +same forms reappear at widely separated parts of the continent. Thus +skulls almost undistinguishable from one another may be met with from +Vancouver’s Island, from Peru, and from Patagonia. + +Naturalists who have admitted but three primary types of the human +species have always found a difficulty with the Americans, hesitating +between placing them with the Mongolian or so-called “yellow” races, or +elevating them to the rank of a primary group. Cuvier, indeed, does not +seem to have been able to settle this point to his own satisfaction, and +leaves it an open question. Although the large majority of Americans have +in the special form of the nasal bones, leading to the characteristic +high bridge of the nose of the living face, in the well-developed +superciliary ridge and retreating forehead, characters which distinguish +them from the typical Asiatic Mongol, yet in many other respects they +resemble them so closely that, while still admitting the difficulties +of the case, we are inclined to include them as aberrant members of the +Mongolian type.[703] It is, however, quite open to any one adopting the +Negro, Mongolian, and Caucasian groups as primary divisions to place the +Americans apart as a fourth. + +Now that the high antiquity of man in America—perhaps as high as that +which he has in Europe—has been discovered, the puzzling problem, from +which part of the Old World the people of America have sprung, has lost +its significance. It is, indeed, quite as likely that the people of Asia +may have been derived from America as the reverse. However this may be, +the population of America, except at the extreme north, was, before the +time of Columbus, practically isolated from the rest of the world. +Such visits as those of the early Norsemen to the coasts of Greenland, +Labrador, and Nova Scotia, or the occasional accidental stranding of +a canoe containing survivors of a voyage across the Pacific or the +Atlantic, can have had little appreciable effect upon the characteristics +of the people. It is difficult, therefore, to look upon the anomalous and +special characters of the American people as the effects of crossing, as +was suggested in the case of the Australians—a consideration which gives +more weight to the view of treating them as a distinct primary division. + +III. The Caucasian, Eurafrican, or white division, includes the two +groups called by Professor Huxley Xanthochroi and Melanochroi, which, +though differing in colour of eyes and hair, agree so closely in all +other anatomical characters, so far, at all events, as has at present +been demonstrated, that it seems preferable to consider them both as +modifications of one great type than as primary divisions of the species. +Whatever their origin may have been, they are now intimately blended, +though in different proportions, throughout the whole of the region of +the earth they inhabit; and it is to the rapid extension of both branches +of this race that the great changes now taking place in the ethnology of +the world are mainly due. + +A. The Xanthochroi, or blonde type, with fair hair, eyes, and complexion, +chiefly inhabit Northern Europe (Scandinavia, Scotland, and North +Germany), but, although much mixed with the next group, they also extend +as far as Northern Africa and Afghanistan. Their mixture with Mongoloid +people has given rise to the Lapps, Finns, and some of the tribes of +Northern Siberia. + +B. Melanochroi, with black hair and eyes, and skin of almost all shades +from white to black. They comprise the great majority of the inhabitants +of Southern Europe, Northern Africa, and South-West Asia, and consist +mainly of the Aryan, Semitic, and Hamitic families. The Dravidians of +India, the Veddahs of Ceylon, and probably the Ainos of Japan, and the +Maoutze of China, also belong to this race, which may have contributed +something to the mixed character of some tribes of Indo-China and +the Polynesian Islands, and, as before said, have given at least the +characters of the hair to the otherwise Negroid inhabitants of Australia. +In Southern India they are largely mixed with a Negrito element, and in +Africa, where their habitat becomes coterminous with that of the Negroes, +numerous cross-races have sprung up between them all along the frontier +line. The ancient Egyptians were nearly pure Melanochroi, though often +showing in their features traces of their frequent intermarriages with +their Ethiopian neighbours to the south. The Copts and fellahs of modern +Egypt are their little-changed descendants. + +In offering this scheme of classification of the varieties of the human +species, it is not suggested that it is one universally accepted by +anthropologists, or that it is likely to be final. Whatever care be +bestowed upon the arrangement of already acquired details, or whatever +judgment be shown in their due subordination one to another, the +acquisition of new knowledge may at any time call for a complete or +partial rearrangement of the system. The difficulties which encompass +the subject have, indeed, been already indicated, and will be found +abundantly illustrated in the writings of those authors who have +specially devoted themselves to its elucidation. + + _Bibliography._—P. Topinard, _Éléments d’Anthropologie + Générale_, 1885; A. de Quatrefages, _Histoire Générale + des Races Humaines_ (1. _Questions Générales_, 1887; 2. + _Classification des Races Humaines_, 1889); Quatrefages and + Hamy, _Crania Ethnica_ (1873-1879); D. G. Brinton, _Races and + Peoples_, 1890. + + + + +FOOTNOTES + + +[1] Galton’s _South Africa_, p. 187. + +[2] L. F. E. Rousseau, _Anatomie comparée du Système dentaire chez +l’Homme et chez les principaux Animaux_, 2d ed., 1839; F. Cuvier, _Des +Dents des Mammifères considérées comme caractères zoologiques_, 1822-25; +R. Owen, _Odontography_, 1840-45; C. G. Giebel, _Odontographie_, 1855; C. +S. Tomes, _Manual of Dental Anatomy, Human and Comparative_, 3d ed., 1889. + +[3] The lower incisors of some species of Shrews are, however, said to +become ankylosed to the jaw in adult age. + +[4] The teeth of the extinct Dinosaurian reptile _Triceratops_ have two +distinct roots, placed transversely to the axis of the jaws. + +[5] This and other questions concerning the homologies, notation, and +succession of the teeth of mammals are more fully developed in two +memoirs by one of the present writers:—“Remarks on the Homologies and +Notation of the Teeth of the Mammalia,” in the _Journal of Anatomy and +Physiology_, vol. iii. p. 262, 1869; and “Notes on the First or Milk +Dentition of the Mammalia,” in the _Trans. Odontological Society of Great +Britain_, 1871. See also an important memoir by Oldfield Thomas on the +“Homologies and Succession of the teeth in the Dasyuridæ,” _Phil. Trans._ +1887, pp. 443-462. + +[6] By many writers the letters indicating the different kinds of teeth +are printed in capitals, as _I_, _C_, _P_, and _M_; while very frequently +the symbol _Pm_ is employed in place of _p_. + +[7] According to Mr. G. E. Dobson there are four upper incisors in some +of the _Soricidæ_. + +[8] See for the principal modifications of the skeleton of the class, +the large and beautifully illustrated _Ostéographie_ of De Blainville, +1835-54; the section devoted to the subject in Bronn’s _Klassen und +Ordnungen des Thier-Reichs_, by Giebel, 1874-79; and _An Introduction to +the Osteology of the Mammalia_, by W. H. Flower, 3d ed., 1885. + +[9] This and many of the following figures in this chapter are taken from +Flower’s _Osteology of the Mammalia_. + +[10] For the sake of uniformity, in all the following descriptions of +the vertebral column, the long axis of the body is supposed to be in the +horizontal position. + +[11] The opinion has recently been expressed by Baur that bone termed +radiale in Fig. 17 is really a second centrale, and that the radiale is +represented by a minute bone generally known as the radial sesamoid. The +mammalian scaphoid is accordingly also regarded as a second centrale. In +the same communication, Dr. Baur expresses his disbelief in the existence +of remnants of a prepollex and of a seventh digit in mammals and other +vertebrates. (See _Anat. Anzeiger_, vol. iv. pp. 49-52, 1889.) + +[12] On the Præpollex and Præhallux, etc., _Proc. Zool. Soc._ 1889, pp. +259-262. + +[13] Cope and Baur consider that the astragalus corresponds only with the +intermedium, and that the tibiale may exist as a distinct element. + +[14] For further details of these modifications, see Flower’s “Lectures +on the Comparative Anatomy of the Organs of Digestion of the Mammalia,” +_Medical Times and Gazette_, Feb.-Dec. 1872. + +[15] G. Gulliver, _Proc. Zool. Soc._, 1862, p. 91. + +[16] The modifications of these bones are fully described by A. Doran, +“Morphology of the Mammalian _Ossicula auditus_,” _Trans. Linn. Soc._ +ser. 2, vol. i. pp. 371-497, pl. lviii.-lxiv. (1878). + +[17] See B. H. Caldwell—“The Embryology of Monotremata and Marsupialia,” +_Phil. Trans._ for 1887, p. 463. + +[18] _Proc. Acad. Nat. Sci. Philadelphia_, 1881, p. 468. + +[19] “_Studien ueber Entwickelungeschichte der Thiere_,” pt. 4, +Wiesbaden, 1886. + +[20] _Journal of Morphology_, vol. i. p. 373 (1887). + +[21] For a full exposition of the present state of knowledge on this +subject, see the various memoirs of Sir William Turner, also F. M. +Balfour’s _Treatise on Comparative Embryology_, vol. ii. (1881), and J. +A. Ryder in _American Naturalist_, vol. xxi. p. 780 (1887). + +[22] _Proceedings of the Royal Society of London_, vol. xxviii. p. 395 +(1879). + +[23] “The Relations between the Theromorphous Reptiles and the Monotreme +Mammalia,” _Proceedings of the American Association for the Advancement +of Science_, vol. xxxiii. p. 471 (1885). + +[24] “On the Phylogenetic Arrangement of the Sauropsida,” _Journal of +Morphology_, vol. i. pp. 93-104 (1887). + +[25] The names of the groups containing only extinct forms are printed in +heavier type than those which contain species still existing. + +[26] On this subject see A. Murray, _Geographical Distribution of +Mammals_, 1866; and especially A. R. Wallace, _The Geographical +Distribution of Animals_, 2 vols., 1876, and _Island Life_, 1881; also A. +Heilprin, _The Geographical and Geological Distribution of Animals_, 1887. + +[27] _Distribution of Animals._ + +[28] Generally known, as _Hyomoschus_, but first described as an extinct +form under the above name. + +[29] The fore limb from S. Africa described as _Theriodesmus_, which +appears to be mammalian, and may belong to _Tritylodon_. + +[30] The subjects referred to under this heading are mostly described +and figured in detail in Owen’s “Monograph of the Fossil Mammalia of the +Mesozoic Formations,” _Palæontographical Society’s Publications_, 1871; +and in various papers by Marsh, in the _American Journal of Science and +Arts_, 1878-89. Important contributions to our knowledge of these forms +have also been made by Professors Cope and Osborn, and the reader should +especially consult the memoir by the latter writer on the “Structure and +Affinities of the Mesozoic Mammals,” published in the _Journal of the +Philadelphia Academy_ (1888), vol. ix. + +[31] The whole discussion is contained in the following memoirs: (1) +H. Falconer, “Description of Two Species of the Fossil Mammalian genus +_Plagiaulax_, from Purbeck,” _Quart. Journ. Geol. Soc._ vol. xiv. +1857; (2) R. Owen, art. “Palæontology,” _Encyclopædia Britannica_, 8th +ed., 1859; (3) H. Falconer, “On the Disputed affinity of the Mammalian +genus _Plagiaulax_,” _Quart. Journ. Geol. Soc._ vol. xviii. 1862; (4) +R. Owen, “Monograph of the Fossil Mammalia of the Mesozoic Formation,” +_Palæontographical Society_, 1871. + +[32] Blumenbach, _Voigts Magazin_, vol. ii. p. 205 (1800). + +[33] _Proceedings of the Royal Society of London_, vol. xliii. p. 353 +(1888). + +[34] _Ibid._ vol. xlvi. p. 126 (1889). + +[35] Cuvier, _Tableau Élémentaire d’Hist. Nat._ p. 143 (1798). + +[36] Gervais, _Ostéographie des Monotremes_, p. 43 (1877). + +[37] For the detailed characters of all the genera and species of +Marsupials the reader should consult the British Museum _Catalogue of +Marsupialia and Monotremata_, by Oldfield Thomas, 1888. + +[38] Except in _Petaurus (Belideus) breviceps_ (Forbes, _Proc. Zool. +Soc._ 1881, p. 188). + +[39] Including the transitional Austro-Malayan region. + +[40] Illiger, _Prod. Syst. Mamm. et Aves_, p. 76 (1811). + +[41] Linn. _Syst. Nat._ Ed. 12, vol. i. p. 71 (1766). + +[42] Temminck, _Monographies de Mammalogie_, vol. i. p. 60 (1827). + +[43] F. Cuvier, _Hist. Nat. des Mammifères_, iv. (1837). + +[44] Geoffroy, _Bull. Soc. Philom._ vol. i. p. 106 (1796). + +[45] Temminck, _Monographies de Mammalogie_, vol. i. p. 56 (1827). + +[46] Thomas, _Ann. Mus. Genov._ sér. 2, vol. iv. p. 503 (1887). + +[47] Krefft, _Proc. Zool. Soc._ 1866, p. 434. + +[48] Waterhouse, _Proc. Zool. Soc._ 1836, p. 69. + +[49] Geoffroy, _Bull. Soc. Philom._ vol. iii. p. 249 (1803). + +[50] Grey, in _Grey’s Australia_, vol. ii, p. 401 (1841). + +[51] Ogilby, _Proc. Zool. Soc._ 1838, p. 25. + +[52] Geoffroy, _Ann. du Muséum_, vol. ii. p. 365 (1803). + +[53] Owen, _Phil. Trans._ 1872, p. 257. + +[54] Gervais and Verraux, _Proc. Zool. Soc._ 1842, p. 1. + +[55] Storr, _Prodromus Meth. Mamm._ p. 33 (1780). Syn. _Phalangista_, +Geoffroy, _Bull. Soc. Philom._ vol i. p. 106 (1796). + +[56] Lesson, _Dict. Class. d’Hist. Nat._ vol. xiii. p. 333 (1828). + +[57] Ogilby, _Proc. Zool. Soc._ 1836, p. 26. + +[58] Thomas, _Cat. Marsupials Brit. Mus._ p. 163 (1888). + +[59] Gray, _Proc. Zool. Soc._ 1858, p. 109. + +[60] Shaw, _Naturalist’s Miscellany_, vol. ii. pl. lx. (1791). + +[61] M’Coy, _Ann. Mag. N. H._ (3) xx. p. 287 (1867). + +[62] Grey, in _Grey’s Australia_, appendix, vol. ii. p. 407 (1841). + +[63] Peters, _Ann. Mus. Genov._ vol. vi. p. 303 (1874). + +[64] Desmarest, _Nouv. Dict. d’Hist. Nat._ sér. 2, vol. xxv. p. 405 +(1817). + +[65] _Cf._ W. A. Forbes, “Anatomy of the Koala,” _Proc. Zool. Soc._ 1881, +p. 180. + +[66] Blainville, _Bull. Soc. Philom._ 1816, p. 116. + +[67] Owen, in _Gervais’s Zool. et Pal. françaises_, 1st ed. pt. i. p. 192 +(1849-52). + +[68] Ramsay, _Proc. Linn. Soc. N. S. Wales_, vol. i. p. 33 (1876). + +[69] De Vis, _Proc. Roy. Soc. Queensland_, ser. 2, vol. iii. p. 8 (1888). + +[70] Desmarest, _Nouv. Dict. d’Hist. Nat._ sér. 1, vol. xxiv. _Table +Méth._ p. 20 (1804). Syn. _Hypsiprymnus_, Illiger, _Prodromus Syst. +Mamm._ p. 79 (1811). + +[71] Gray, _Charlesworth’s Mag. Nat. Hist._ vol. i. p. 584 (1837). + +[72] Thomas, _Cat. Marsup. Brit. Mus._ p. 114 (1888). + +[73] Garrod, _Proc. Zool. Soc._ 1875, p. 59. + +[74] Thomas, _Proc. Zool. Soc._ 1886, p. 544. + +[75] Schlegel and Müller, _Verh. Nat. Ges. Nederland_, p. 138 (1839-44). + +[76] Schlegel and Müller, _Verh. Nat. Ges. Nederland_, p. 130 (1839-44). + +[77] Gould, _Monograph of Macropodidæ_, pl. xiii. (1841). + +[78] Grey, in _Grey’s Australia_, vol. ii. appendix, p. 402 (1841). + +[79] Gray, _Charlesworth’s Mag. Nat. Hist._ vol. i. p. 583 (1837). + +[80] Shaw, _Naturalist’s Miscellany_, vol. i. pl. xxxiii. (1790). + +[81] For the characters of these species and the under-mentioned distinct +genera, see Owen’s _Extinct Mammals of Australia_ (1877), and Lydekker’s +_Catalogue of Fossil Mammalia in the British Museum_, pt. v. (1887). + +[82] Owen, _Phil. Trans._ 1874, p. 264. + +[83] Owen, _op. cit._ p. 788. + +[84] Owen, _op. cit._ p. 797. + +[85] Owen, in _Mitchell’s Eastern Australia_, 2d ed. vol. ii. p. 362 +(1838). + +[86] Owen, _Cat. Mamm. and Aves, Mus. R. Coll. Surgeons_, p. 314 (1845). + +[87] The characters of the chief groups of the Eutheria here given are, +in some measure, a fuller recapitulation of those already detailed in +Chapter III., pp. 83-88. + +[88] The name Paratheria has been suggested for this proposed subclass. + +[89] In some few Armadillos the suture between the premaxilla and maxilla +passes behind the first upper tooth; but in all other known members of +the order all the teeth are implanted in the maxilla. + +[90] See Flower, “On the Mutual Affinities of the Animals composing the +Order Edentata,” _Proceedings of the Zoological Society_, 1882, p. 358. + +[91] An attempt has been made to represent these views by the following +classification: + + Order EDENTATA. + Suborder PILOSA. + _Bradypodidæ._ + _Megatheriidæ._ + _Myrmecophagidæ._ + Suborder LORICATA. + _Dasypodidæ._ + Suborder SQUAMATA. + _Manidæ._ + Suborder TUBULIDENTATA. + _Orycteropodidæ._ + +It may be objected to this arrangement that the _present_ divergence +between the Sloths and Anteaters is hardly sufficiently indicated by +their association in one suborder.—Flower, “On the Arrangement of the +Orders and Families of Mammals,” _Proc. Zool. Soc._ 1883, p. 178. + +[92] Linn. _Syst. Nat._ 12th ed. vol. i. p. 50 (1766). + +[93] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 108 (1811). + +[94] Burmeister, _Sitzb. Ak. Berlin_, vol. xxviii. p. 613 (1882). + +[95] Lydekker, in Nicholson and Lydekker’s _Manual of Palæontology_, +vol. ii. p. 1299 (1889). Originally described under the preoccupied name +_Cœlodon_. + +[96] Cuvier, _Tableau Élém. d’Hist. Nat. des Animaux_, p. 146 (1798). + +[97] An excellent figure of this skeleton, which unfortunately was +incorrectly articulated, and wanted the greater part of the tail, +was published by Pander and D’Alton in 1821, and has been frequently +reproduced in subsequent works. + +[98] See E. D. Cape, _Amer. Naturalist_, vol. xxiii. p. 152 (1889). + +[99] Linn. _Syst. Nat._ 12th ed. vol. i. p. 51 (1766). + +[100] Professor Cope has recently come to the conclusion that there are +three species; but further evidence is required in support of this view. + +[101] Gray, _Annals of Philosophy_, new series, vol. x. p. 343 (1825). + +[102] Gray, _Annals of Philosophy_, new series, vol. x. p. 343 (1825). + +[103] Harlan, _Ann. New York Lyceum Nat. Hist._ vol. i. p. 237 +(1824).—Amended from _Chiamyphorus_. + +[104] Linn. _Syst. Nat._, 12th ed. vol. i. p. 54 (1766). + +[105] Wagler, _Syst. Amphibien_, etc., p. 36 (1830). + +[106] F. Cuvier, _Hist. Nat. des Mammifères_ (1822).—_Priodontes._ + +[107] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 111 (1811). + +[108] Lesson, _Man. de Mammalogie_, p. 309 (1827); _ex._ F. Cuvier, +_Tatusie_. + +[109] A single imperfect skin, brought from the province of Ceara in +Brazil, indicates a very remarkable form of Armadillo, named by A. +Milne-Edwards _Scleropleura brunetti_ (_Ann. Sc. Nat._ xvi. p. 8, 1872). +The dermal scutes are said to be much less developed than in other +members of the family, and confined to the sides, all the median portion +of the back being clothed with a flexible hairy skin. The head is broad +and short, the ears small and far apart. The tail is long, and almost +entirely devoid of scutes. The feet are unknown. + +[110] Linn. _Syst. Nat._ 12th ed. vol. i. p. 52 (1766). + +[111] _Mammalian Descent_, p. 95. + +[112] _Mammalian Descent_, p. 99. + +[113] Forsyth-Major, _Comptes Rendus_, vol. cvii. p. 1180 (1888). + +[114] Geoffroy, _Décade Philosophique_, 1795 (_teste_ Agassiz). + +[115] _Proceedings of the Royal Society_; vol. xlvii. p. 246 (1890). + +[116] Storr, _Prodromus Meth. Mamm._ p. 41 (1780). + +[117] _Zool. Jahrbuch_, vol. i. p. 1 (1886). + +[118] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 140 (1811). + +[119] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 141 (1811).—Amended +from _Rytina_. + +[120] Nordenskiöld, during his voyage in the _Vega_, obtained some +information from the natives of Behring Island which led him to believe +that a few individuals may have survived to a much later date, even to +1854; but this conclusion is disputed by later writers. + +[121] Kaup, _Neues Jahrbuch_, 1838, pp. 319 and 536. + +[122] This is an important distinction from the Sirenia, but a character +common to nearly all other mammals. It is doubtful whether there is any +foundation for the statement that these epiphyses remain ununited for an +exceptionally long period in the Cetacea. + +[123] A character repeated in some of the Seals. + +[124] These have been described in detail by Professor Struthers in the +_Journal of Anatomy and Physiology_, 1881. + +[125] The ankylosed mass of cervical vertebræ, on which the genus +_Palæocetus_ was established, was regarded by its describer as having +probably come from the Kimeridge Clay, but the mineral condition of the +specimen points to the Red Crag as the place of origin. + +[126] There is much resemblance in the larynx of the Hippopotamus, but +none in that of the Seal, to the same organ in the Cetacea. + +[127] German _Meerschwein_, whence the French _Marsouin_. “Porpoise” is +said to be derived from “_Porc-poisson_.” + +[128] Icel. _hvalr_; Dan. and Swed. _hval_; Anglo-Saxon _hwæl_; Germ. +_wal_, _walfisch_. The meaning apparently is “roller,” the word being +closely allied to “wheel” (Skeat). + +[129] These were discovered in the Greenland Whale by Geoffroy St. +Hilaire, whose observations were confirmed and extended to other genera +by Eschricht. They have been very fully described in _Balænoptera +rostrata_ by Julin (_Archives de Biologie_, i. 1880). + +[130] For the structure of whalebone see Hunter, “Observations on the +Structure and Economy of Whales,” _Phil. Trans._ 1787; Eschricht and +Reinhardt, _On the Greenland Right Whale_, English translation by the Ray +Society, 1866, pp. 67-78; and Sir W. Turner, in _Trans. Roy. Soc. Edin._ +1870. + +[131] Linn. _Syst. Nat._ 12th ed. vol. i. p. 105 (1766). + +[132] Gray, _Suppl. Cat. Seals and Whales in Brit. Mus._ p. 39 (1871). + +[133] Cope, _Proc. Ac. Nat. Sci. Philad._ 1869, p. 15. + +[134] Gray, _Zoology of Erebus and Terror_, p. 16 (1846). + +[135] See J. Struthers, “On the Anatomy of _Megaptera longimana_,” +_Journ. Anatomy and Physiology_, 1887-89. + +[136] Lacépède, “Table des Ordres,” _Hist. Nat. des Cétacés_, p. xxxvi. +(1804). + +[137] See P. J. Van Beneden, “Histoire Naturelles des Balénoptères,” +_Mém. Acad. Belgique_, xli. 1887. + +[138] In a recent memoir Professor D’Arcy Thompson has brought forward +some arguments to show that the Zeuglodonts have no direct affinities +with the Cetacea, but have on the other hand the strongest possible +relation with the Pinnipede Carnivora. “On the Systematic position of +Zeuglodon,” _Studies from the Museum of Zoology, Dundee_, vol. i. No. 9, +1890. + +[139] An appearance in one specimen has been described by C. G. Carus +as indicating a vertical succession of the teeth, but the evidence upon +which this rests is by no means satisfactory, and appears to admit of +another explanation. + +[140] A mutilated humerus of _Zeuglodon cetoides_ has given rise to many +conjectures, appearing to some anatomists to indicate seal-like freedom +of motion at the elbow-joint, while to others its characters appear to be +truly Cetacean. + +[141] See _Trans. Geol. Soc._ ser. 2, vol. vi. p. 67. + +[142] Linn. _Syst. Nat._ 12th ed. vol. i. p. 107 (1766). + +[143] Gray, _Zoology of Erebus and Terror_, p. 22 (1846). Usually spelt +_Kogia_. + +[144] Lacépède, “Table des Ordres,” _Hist. Nat. des Cétacés_, p. xliv. +(1804). + +[145] See the figures in the _Proc. Zool. Soc._ 1882, pp. 728, 729. + +[146] Cuvier, _Ossemens Fossiles_, 2d ed. vol. v. p. 352 (1823). + +[147] Gervais, _Ann. Sci. Nat._ ser. 3, vol. xiv. p. 16 (1850). For the +very complicated synonymy of this genus, see _Trans. Zool. Soc._ vol. +viii. p. 208. + +[148] Duvernoy, _Ann. Sci. Nat.-Zoologie_, sér. 3, vol. xv. p. 41 (1851). + +[149] Duvernoy, _op. cit._ p. 61. + +[150] Grateloup, _Act. Ac. R. Sci. Bordeaux_, 1840, p. 208. + +[151] Wagler, _Syst. Amphib._ etc., p. 35 (1830). + +[152] The anatomy of _Platanista_ is fully described by J. Anderson, +_Zoological Results of Two Expeditions to Western Yunnan_, 1878. + +[153] D’Orbigny, _Nouv. Ann. Mus. Paris_, vol. iii. p. 31 (1834). + +[154] Gray, _Zoology of Erebus and Terror_, p. 46 (1846). + +[155] Linn. _Syst. Nat._ 12th ed. vol. i. p. 105 (1766). + +[156] Lacépède, _Hist. Nat. des Cétacés_, p. xli. (1804). + +[157] Cuvier, _Règne Animal_, vol. i. p. 279 (1817). + +[158] _Zoology of Erebus and Terror_, p. 30 (1846). The name is +preoccupied by Lamarck for a genus of Polyzoa (1816). + +[159] Gray, _Cat. Cetacea Brit. Mus._ p. 106 (1850). + +[160] Gray, _Cat. Seals and Whales in Brit. Mus._ p. 285 (1866). + +[161] _Anatomical and Zoological Researches, comprising an Account of the +Zoological Results of the two Expeditions to Western Yunnan, in 1868 and +1875_ (1878). + +[162] Gray, _Zoology of Erebus and Terror_, p. 33 (1846). + +[163] Reinhardt, _Overs. Dan. Sezsk. Forh._ 1862, p. 151. + +[164] Lesson, _N. Tab. d. Règne Animal—Mamm._ p. 200 (1842). + +[165] Gray, _Zoology of Erebus and Terror_, p. 30 (1846). + +[166] Gray, _Proc. Zool. Soc._ 1870, p. 77. + +[167] Gray, _Zoology of Erebus and Terror_, p. 35 (1846). + +[168] Linn. _Syst. Nat._ 12th ed. vol. i. p. 108 (1766). + +[169] Gervais, _Hist. Nat. des Mammifères_, vol. ii. p. 323 (1855). + +[170] Gervais, _Ostéographie des Cétacés_, p. 604 (1880). + +[171] Gray, _Zoology of Erebus and Terror_, p. 43 (1846). + +[172] Gray, _Cat. Seals and Whales Brit. Mus._ 2d ed. p. 393 (1866). + +[173] Since this was in type the discovery of transient rudimentary +clavicles in the embryo of the Sheep has been announced by Wineza +(_Morpholog. Jahrb._ xvi. p. 647). + +[174] Also known as Diplarthra. + +[175] The pollex is present in the manus of the extinct _Cotylops_. + +[176] In the table on p. 89 the Peccaries are included in the _Suidæ_. + +[177] Linn. _Syst. Nat._ 12th ed. vol. i. p. 101 (1766). + +[178] Linn. _Syst. Nat._ 12th ed. vol. i. p. 102 (1766). + +[179] If from any accidental circumstances these teeth are not constantly +worn down by friction, they grow into a complete circle, the point +penetrating the bone of the jaw close to the root of the tooth. The +natives of the Fiji Islands avail themselves of this circumstance to +produce one of their most valued ornaments—a circular boar’s tusk: the +upper canines being extracted, the lower ones are allowed to grow to the +desired form. + +[180] See Garson, _Proc. Zool. Soc. Lond._ 1883, p. 413. + +[181] Lesson, _Man. d. Mamm._, p. 337 (1827), “Babirusa.” + +[182] Cuvier, _Règne-Animal_, vol. i. p. 236 (1817). + +[183] Cuvier, _Règne Animal_, vol. i. p. 237 (1817). + +[184] Professor Cope considers that there is a third species, for which +he has proposed the name _D. angularis_. + +[185] This name (Leidy, 1851) is preoccupied by _Orodus_ (Agassiz, 1838). + +[186] The stomach of the Camel inhabiting the Arabian desert is commonly +looked upon as a striking example of specialised structure, adapted or +modified in direct accordance with a highly specialised mode of life; it +is therefore very remarkable to find an organ exactly similar, except in +some unessential details, in the Llamas of the Peruvian Andes and the +Guanacos of the Pampas. No hypothesis except that of a common origin will +satisfactorily account for this, and, granting that this view is correct, +it becomes extremely interesting to find for how long a time two genera +may be isolated and yet retain such close similarities in parts which in +other groups appear readily subject to adaptive modifications. + +[187] Linn. _Syst. Nat._ 12th ed. vol. i. p. 90 (1766). + +[188] There is much confusion as to the proper use of the names Camel and +Dromedary. It is now generally accepted that the former is the common +term for all the members of the genus, and that Dromedary should be +confined to the lighter and swifter breeds of the one-humped species. One +of the oldest pictures of the two-humped Camel extant, painted on the +wall of the Chapter House of Westminster Abbey, has, however, “Dromedary” +inscribed under it. + +[189] Illiger, _Prodromus Syst. Mamm._ p. 103 (1811). + +[190] _Natural History of the Strait of Magellan_, 1871. + +[191] Pallas, _Spicilegia Zoologica_, vol. xiii. p. 27 (1779). + +[192] Kaup, _Ossemens Fossiles de Darmstadt_, pt. 5, p. 92 (1836). This +name, which was proposed for a fossil species, antedates _Hyomoschus_, +Gray, applied to the living form. + +[193] For the anatomy of this group see A. H. Garrod, _Proc. Zool. Soc._ +1877, p. 2. + +[194] Linn. _Syst. Nat._ 12th ed. vol. i. p. 91 (1766). + +[195] For the anatomy of _Moschus_ see Flower, _Proc. Zool. Soc._ 1875, +p. 159; and Garrod, _ibid._ 1877, p. 287. + +[196] _Proc. Zool. Soc._ 1878, p. 889. + +[197] De Blainville, _Bull. Soc. Philom._ 1816, p. 74. + +[198] Milne-Edwards, _Nouv. Arch. du Muséum_, vol. vii. Bull. p. 93 +(1872). + +[199] Linn. _Syst. Nat._ 12th ed. vol. i. p. 92 (1766). + +[200] Hamilton-Smith, in _Griffith’s Animal Kingdom_, vol. v. p. 304 +(1827). + +[201] Hamilton-Smith, in _Griffith’s Animal Kingdom_, vol. v. p. 303 +(1827). + +[202] Scott, _Proc. Ac. Nat. Sci. Philad._ 1885, p. 181. + +[203] Hamilton-Smith, in _Griffith’s Animal Kingdom_, vol. v. p. 313 +(1827). + +[204] Swinhoe, _Proc. Zool. Soc._ 1870, p. 90. + +[205] Gray, _Proc. Zool. Soc._ 1850, p. 237. + +[206] Gray, _Proc. Zool. Soc._ 1850, p. 242. + +[207] This accessory column is shown in the figure of the molar of +_Boselaphus_ on p. 311. + +[208] Zimmermann, _Geograph. Geschichte_, vol. ii. p. 125 (1780). + +[209] Ord. _Journ. de Physique_, vol. lxxxvii. p. 149 (1818). + +[210] Blainville, _Bull. Soc. Philom._ 1816, p. 75. + +[211] Lichtenstein, _Berlin Ges. Natuforsch. Freunde Magazin_, vol. vi. +pp. 152, 165 (1814). + +[212] F. E. Blaauw, _Proc. Zool. Soc._ 1889, p. 2. + +[213] Hamilton-Smith, in _Griffith’s Animal Kingdom_, vol. iv. p. 258 +(1827). Taken to include _Grimmia_, _Terphone_, etc., of Gray. + +[214] Leach, _Trans. Linn. Soc._ vol. xiv. p. 524 (1823). + +[215] Hamilton-Smith, in _Griffith’s Animal Kingdom_, vol. iv. p. 269 +(1827). + +[216] _Geology and Zoology of Abyssinia_, p. 268. + +[217] Sundevall, _Kongl. Vetensk. Akad. Handl._ for 1844, p. 191. Taken +to include _Calotragus_, _Scopophorus_, _Nesotragus_, _Pediotragus_, and +_Oreotragus_ of Gray. + +[218] See V. Brooke, _Proc. Zool. Soc._ 1872, pp. 642 and 875. + +[219] Gray, _Cat. Ungulate Mamm. Brit. Mus._ p. 90 (1852). + +[220] Andrew Smith, _Illustrations of Zoology of South Africa_, No. 12 +(1840), “Kobus.” Is taken to include _Adenota_ and _Onotragus_ of Gray. + +[221] De Blainville, _Bull. Soc. Philom._ 1816, p. 75. Syn. _Eleotragus_. + +[222] Pallas, _Spicilegia Zoologica_, vol. i. p. 3 (1767). + +[223] Sundevall, _Kongl. Vetensk. Akad. Handl._ for 1845, p. 271. + +[224] Gray, _List Mamm. Brit. Mus._ p. 160 (1843). + +[225] Hodgson, _Proc. Zool. Soc._ 1834, p. 81. + +[226] De Blainville, _Bull. Soc. Philom._ 1816, p. 75. Is taken to +include _Procapra_ and _Tragops_. + +[227] _Proc. Zool. Soc._ 1873, p. 537. Three species subsequently +described are here added to the list. + +[228] Sundevall, _Kongl. Vetensk. Akad. Handl._ for 1844, p. 196. + +[229] De Blainville, _Bull. Soc. Philom._ 1816, p. 75. + +[230] Rafinesque, _Anal. Nat._ 1815, p. 56. + +[231] De Blainville, _Bull. Soc. Philom._ 1816, p. 75. Syn. _Portax_, +Hamilton-Smith. + +[232] De Blainville, _Bull. Soc. Philom._ 1816, p. 75. Includes +_Euryceros_, Gray. + +[233] Gray, _List. Mamm. Brit. Mus._ p. 155 (1843). + +[234] Desmarest, _Mammalogie_, p. 471 (1822). + +[235] De Blainville, _Bull. Soc. Philom._ 1816, p. 75. + +[236] Hamilton-Smith, in _Griffith’s Animal Kingdom_, vol. v. p. 352 +(1827). + +[237] Hamilton-Smith, in _Griffith’s Animal Kingdom_, vol. v. p. 354 +(1827). Amended from “Aplocerus.” + +[238] Hodgson, _Journ. As. Soc. Bengal_, vol. xix. p. 65 (1850). + +[239] See A. O. Hume, _Proc. Zool. Soc._ 1887, pp. 483-486. + +[240] Linn. _Syst. Nat._ 12th ed. vol. i. p. 94 (1766). + +[241] _Proc. Zool. Soc._ 1886, p. 314; and 1887, p. 552. + +[242] Specimens referred by Dinnik to _C. caucasica_ have been made the +types of another species—_C. severtzovi_. + +[243] Linn. _Syst. Nat._ 12th ed. vol. i. p. 97 (1766). + +[244] There may be a beard on the throat, as in _O. cycloceros_. + +[245] _Proc. Zool. Soc._ 1884, p. 326. + +[246] De Blainville, _Bull. Soc. Philom._ 1816, p. 76. + +[247] _Zoologist_, September 1877. + +[248] Linn. _Syst. Nat._ 12th ed. vol. i. p. 98 (1766). + +[249] _Proc. Zool. Soc._ 1873, p. 474. + +[250] Sir V. Brooke states that this species is distinguished from _B. +pumilus_ by the absence of a fringe to the ears, but specimens in the +British Museum show that this is not the case. + +[251] _The Extirpation of the American Bison_, 1889. + +[252] The late Mr. Alston, _Fauna of Scotland_, “Mammalia” (Glasgow, +1880), p. 25, considers that the Chillingham cattle are descendants of a +race which had escaped from domestication. + +[253] Wanting in the aberrant _Chalicotherium_. + +[254] See W. N. Parker, _Proc. Zool. Soc._ 1882, p. 775. + +[255] Cuvier, _Tableau Élément. de l’Hist. Nat._ p. 152 (1798); _ex_ +Brisson. + +[256] See J. Murie, _Journ. Anat. and Physiol._ vol. vi. p. 131, 1871; +W. N. Parker. _Proc. Zool. Soc._ 1882, p. 768; and F. E. Beddard, _Proc. +Zool. Soc._ 1889, p. 252. + +[257] The Swiss _P. siderolithicus_ has only one cusp in the last upper +premolar. + +[258] Leidy, _Proc. Ac. Nat. Sci. Philad._ 1858, p. 26. + +[259] Christol, _Ann. Sci. Indust. Mid. France_, vol. i. p. 180 (1832). + +[260] Linn. _Syst. Nat._ 12th ed. vol. i. p. 100 (1766). + +[261] Darwin, _Variation of Animals and Plants under Domestication_, +1868, vol. i. chap. ii. + +[262] See _Nature_, 21st August 1884, and _Zool. Garten._ vol. xxviii. p. +453. + +[263] See Sclater, _Proc. Zool. Soc._ 1884, p. 542. + +[264] See Blanford, _Zoology and Geology of Eastern Persia_ (_Journeys of +the Persian Boundary Commission_), p. 84. + +[265] This must not be confounded with the navicular of the tarsus. + +[266] Want of space and of the necessary illustrations rendered it +impossible to give an account of mammalian myology in the earlier +chapters of this work. + +[267] Linn. _Syst. Nat._ 12th ed. vol. i. p. 104 (1766). + +[268] Many authors use Cuvier’s name, _R. indicus_, in preference to +this, on the ground that there are more than one species with one +horn, forgetting that the name substituted is equally inconvenient, +as more than one species live in India. The fact of a specific name +being applicable to several members of a genus is no objection to its +restriction to the first to which it was applied; otherwise changes +in old and well-received names would constantly have to be made in +consequence of new discoveries. + +[269] _Trans. Zool. Soc._ vol. xii.; see also _Proc. Zool. Soc._ 1889, p. +9. + +[270] See Beddard and Treves, _Proc. Zool. Soc._ 1889, p. 9. + +[271] For the internal anatomy of _R. sumatrensis_ see Garrod, _Proc. +Zool. Soc._ 1873, p. 92; and Beddard and Treves, _loc. cit._ + +[272] Those external points of distinction from _R. simus_ are taken from +a paper by Sclater in the _Proc. Zool. Soc._ 1886, p. 143. + +[273] _Proc. Zool. Soc._ 1881, p. 726. + +[274] This name is the earliest, but is preoccupied. + +[275] Hermann, _Tab. Affinit. Anim._ p. 115 (1783). It has recently +been proposed to substitute the earlier name _Procavia_ in lieu of +_Hyrax_. The anatomy of Hyrax was first described by Pallas (_Spicilegia +Zoologica_). Besides minor memoirs, two detailed accounts of its +structure have appeared—one by Brandt, in _Mém. Acad. Nat. Scien. St. +Pétersbourg_, 7ⁱᵉᵐᵉ sér. vol. xiv. No. 2, 1869; and another by George, +in _Annales des Sciences Naturelles_, 6ⁱᵉᵐᵉ sér. tom. i. 1874, in which +references to all the previous literature will be found. The mechanism +by which the sole of the foot is enabled to adhere to smooth surfaces is +fully described by G. E. Dobson, _Proc. Zool. Soc._ 1876, p. 526. + +[276] Gray, _Ann. Mag. Nat. Hist._ ser. 4. vol. i. p. 48 (1868). + +[277] See a paper by J. V. Barboza du Bocage, in the _Jorn. Sci. Phys. +Nat. Lisboa_ (2), vol. i. p. 186 (1889), where a list of all the known +species will be found. + +[278] These teeth are by some writers classed as canines, as their roots +are implanted in the maxillæ; but, as in Rodents, they are originally +developed in the gum covering the premaxillæ, in which bones their +primitive alveoli are sunk. As growth proceeds, however, firm support +for such massive and weighty bodies can only be obtained by their roots +gradually sinking through the premaxillæ into the great and specially +modified alveolar processes of the maxillæ, but this does not vitiate +their homology with the incisors of other mammals. + +[279] Linn. _Syst. Nat._ 12th ed. vol. i. p. 48 (1766). + +[280] In the Gulf of Cambay,—not the island of the same name in the Red +Sea. + +[281] The word Mammoth was introduced into the languages of Western +Europe about two centuries ago from the Russian, and is thought by +Pallas and Nordenskiöld to be of Tartar origin, but others, as Witzen, +Strahlenburg, and Howorth, have endeavored to prove that it is a +corruption of the Arabic word _Behemoth_, or great beast. + +[282] The best known of these is the etching upon a portion of tusk +found in the cave of La Madelaine in the Dordogne, figured in Lartet and +Christy’s _Reliquiæ Aquitanicæ_, and in many other works bearing on the +subject of the antiquity of man. + +[283] Cuvier, _Ann. du Muséum_, vol. viii. p. 270 (1806). + +[284] This, and the larger number of ridges in the latter, are the only +absolute distinctions which Falconer could find between _Mastodon_ and +_Elephas_ (_Palæont. Memoirs_, ii. p. 9), and it is clear that they are +somewhat arbitrary. The line between the two genera is drawn at this +point more as a matter of convenience for descriptive purposes than as +indicating any great natural break in the sequence of modifications of +the same type. + +[285] Also found beyond the extreme north-western frontier of India. + +[286] Kaup, _Isis_, vol. xxii. p. 401 (1829). + +[287] Leidy, _Proc. Ac. Nat. Sci. Philad._ 1872, p 169. + +[288] For detailed descriptions and figures of this group, see Marsh, +“Monograph of the Dinocerata,” _Rep. U.S. Geol. Surv._ vol. x. (1884). + +[289] Owen, _Brit. Foss. Mamm. and Birds_, p. 299 (1846). + +[290] See G. E. Dobson, _Journ. Anat. Phys._ vol. xvii. + +[291] Waterhouse, _Proc. Zool. Soc._ 1842, p. 124. + +[292] _Proc. Zool. Soc._ 1882, p. 8. + +[293] Linn. _Syst. Nat._ 12th ed. vol. i. p. 86 (1766). + +[294] Gray, _Ann. Mag. Nat. Hist._ ser. 3, vol. xx. p. 272 (1867). + +[295] Hemprich and Ehrenberg, _Symbol. Phys. Mamm._ vol. i. (1832). + +[296] Illiger, _Prodromus Syst. Mamm._ p. 83 (1811). + +[297] Some American zoologists have recently proposed to raise a large +number of the forms usually regarded as local races to the rank of +species. + +[298] Cuvier, _Leçons d’Anatomie Comp._ (1800). + +[299] Cuvier, _Ann. du Muséum_, vol. x. p. 126 (1825). + +[300] O. Thomas, _Journ. As. Soc. Bengal_, vol. lvii. p. 256 (1888). + +[301] Schreber, _Säugethiere_, vol. iv. p. 721 (1792). + +[302] Rafinesque, _Amer. Monthly Mag._ vol. ii. p. 45 (1817). + +[303] F. Cuvier, _Mém. du Muséum_, vol. vi. p. 293 (1822). + +[304] Richardson, _Zool. Journ._ vol. iv. p. 334 (1829). Amended. + +[305] Linn. _Syst. Nat._ 12th ed. vol. i. p. 78 (1766). + +[306] For a monograph of the _Myoxidæ_, see C. L. Reuvens, _Die Myoxidæ_, +etc., 4to, Leyden, 1890. + +[307] Schreber, _Säugethiere_, vol. iv. p. 824 (1792). + +[308] Wagner, _Abh. baier. Akad._ vol. iii. p. 179 (1843). + +[309] F. Cuvier, _Mammifères_, 60ᵐᵉ livr. (1845). + +[310] Jentink, _Notes Leyd. Mus._ vol. x. p. 41 (1888). + +[311] Kaup, _Entwickl. Europ. Thierwelt_, p. 139 (1829). + +[312] A. Milne-Edwards, _L’Institut_, vol. xxxv. p. 46 (1867). + +[313] _Sminthus_ is referred to the _Dipodidæ_. + +[314] Geoffrey, _Ann. du Muséum_, vol. vi. p. 81 (1805). + +[315] For the anatomy of this animal see B. C. A. Windle, _Proc. Zool. +Soc._ 1887, p. 53. + +[316] O. Thomas, _Proc. Zool. Soc._ 1889, p. 247. + +[317] Blyth, _Proc. As. Soc. Bengal_, vol. xxviii. p. 289 (1859). + +[318] Desmarest, _Nouv. Dict. d’Hist. Nat._ vol. xxiv. p. 22 (1804). + +[319] Lataste, _Le Nat._ vol. i. p. 314 (1880). + +[320] Wagner, _Wiegmann’s Archiv_, 1841, p. 132. + +[321] F. Cuvier, _Dents des Mammifères_, p. 168 (1825). + +[322] Peters, _Monatsber. Ak. Berlin_, 1875, p. 12. + +[323] A. Milne-Edwards, _Bull. Soc. Philom._ sér. 6, vol. xi. p. 9 (1877). + +[324] _Nesocia_ was included by Alston in this subfamily. + +[325] Waterhouse, _Proc. Zool. Soc._ 1839, p. 108. + +[326] Andrew Smith, _S. African Quart. Journ._ vol. ii. p. 158 (1834). + +[327] Peters, _Reise n. Mossambique_, vol. i. p. 162 (1852). + +[328] Peters, _Monatsber. Ak. Berlin_, 1874, p. 234. + +[329] Cuvier, _Règne Animal_, vol. i. p. 198 (1817). + +[330] _Proc. Zool. Soc._ 1888, p. 133. + +[331] _Proc. Zool. Soc._ 1884, p. 451. + +[332] Brandt, _Mém. Acad. Imp. St. Pétersbourg_, sér. 3, iii. p. 428 +(1835). + +[333] Say and Ord, _Journ. Acad. Philad._ vol. iv. p. 352 (1825). + +[334] Waterhouse, _Proc. Zool. Soc._ 1837, p. 29. + +[335] Coues, _Proc. Acad. Philad._ 1874, p. 184. + +[336] Say and Ord, _Journ. Acad. Philad._ vol. iv. p. 346 (1825). + +[337] Grandidier, _Rev. and Mag. Zool._ 1869, p. 388. + +[338] Peters, _Sitzber. Ges. Nat. Freunde_, 1870, p. 54 (1871). + +[339] Günther, _Proc. Zool. Soc._ 1875, p. 79. + +[340] Jentink, _Notes Leyd. Mus._ vol. i. p. 107, note 27 (1879). + +[341] Milne-Edwards, _Ann. Sci. Nat._ sér. 6, vol. xx. art. 1, _bis_, p. +1 (1886). + +[342] Merriam, _Fauna of North America_, No. 2, p. 28 (1889). + +[343] Lacépède, _Mém. de l’Institut_, vol. iii. p. 495 (1801). Many +writers employ the earlier name _Microtus_ for the true Voles. + +[344] Baird, _Mamm. North America_, pp. xliv. 558 (1857). + +[345] Pallas, _Zoogr. Rosso-Asiat._ vol. i. p. 173 (1811). + +[346] Wagler, _Isis_, 1832, p. 1220. + +[347] Cuvier, _Leçons d’Anatomie Compar._ tab. 1 (1800). + +[348] True, _Proc. U.S. Nat. Mus._ vol. vii. p. 170 (1884). + +[349] Fischer, _Zoognosia_, vol. iii. p. 72 (1814). + +[350] Brants, _Het. Geslact der Muizen_, p. 20 (1827). + +[351] O. Thomas. _Proc. Zool. Soc._ 1888, p. 130. + +[352] Linn. _Syst. Nat._ 12th ed. vol. i. p. 79 (1766). + +[353] Gray, _Ann. Mag. Nat. Hist._ vol. x. p. 264 (1842). Amended from +_Nesokia_. + +[354] Gray, Charlesworth’s, _Mag. Nat. Hist._ vol. i. p. 586 (1837). Syn. +_Pelomys_, Peters (1852). + +[355] Peters, _Monatsber. Ak. Berlin_, 1867, p. 343. + +[356] O. Thomas, _Proc. Zool. Soc._ 1888, p. 237. + +[357] Lichtenstein, _Darst. neu. Säugethiere_, pt. iv. pl. 29 (1829). + +[358] O. Thomas, _Ann. Mag. Nat. Hist._ ser. 5, vol. ix. p. 413 (1882). + +[359] Geoffroy, _Ann. Sci. Nat._ sér. 2, vol. x. p. 126 (1840). _Acomys._ + +[360] Gray, _Proc. Zool. Soc._ 1867, p. 599. Amended from _Echimys_. + +[361] Milne-Edwards, _Bull. Soc. Philom._ sér. 6, vol. xi. p. 9 (1877). + +[362] Waterhouse, _Proc. Zool. Soc._ 1840, p. 2. + +[363] Peters, _Monatsber. Ak. Berlin_, 1846, p. 258. + +[364] Güldenstädt, _Nov. Comment. Petrop._ vol. xiv. art. i. p. 409 +(1770). + +[365] Gray, _Proc. Zool. Soc._ 1830, p. 95. + +[366] Illiger, _Prodromus Syst. Mamm._ p. 86 (1811). + +[367] Illiger, _loc. cit._ p. 87. + +[368] O. Thomas, _Proc. Zool. Soc._ 1890, p. 448 = _Heliophobius_; +Peters, _Monatsber. Ak. Berlin_, 1846, p. 243.—Preoccupied. + +[369] Rüppel, _Mus. Senkenb._ vol. i. Säugeth. p. 99 (1834). + +[370] Including the _Saccomyidæ_ of Coues. + +[371] Rafinesque, _Amer. Monthly Mag._ vol. ii. p. 45 (1817). + +[372] Wied, _Nova Acta Ac. Cæs. Leop.-Car._ vol. xix. pt. i. p. 383 +(1839). + +[373] Gray, _Ann. Mag. Nat. Hist._ vol. vii. p. 521 (1840). + +[374] Wied, _Nova Acta Ac. Cæs. Leop.-Car._ vol. xix. pt. i. p. 369 +(1839). + +[375] Desmarest, _Mammalogie_, p. 313 (1820). + +[376] Keyserling und Blasius, _Wirbelthiere Europ._ p. 38 (1840). + +[377] Coues, _Bull. U.S. Geol. Surv. Terrs._ ser. 2, No. 5, p. 253 +(1873). Syn. _Jaculus_, Wagler. + +[378] Gmelin, _Syst. Nat._, vol. i. p. 157 (1788). + +[379] F. Cuvier, _Proc. Zool. Soc._ 1836, p. 141. + +[380] Brandt, _Bull. Ac. St. Pétersbourg_, 1844, p. 209. + +[381] = _A. jaculus_, Auct. + +[382] Illiger, _Prodromus Syst. Mamm._ p. 81 (1811). + +[383] Gray, _Spicilegia Zoologica_, p. 10 (1830). + +[384] Blyth, _Journ. As. Soc. Bengal_, vol. xxxiv. p. 294 (1855). + +[385] Bennett, _Proc. Zool. Soc._ 1832, p. 46. + +[386] Waterhouse, _Proc. Zool. Soc._ 1837, p. 30. Amended from _Abrocoma_. + +[387] Waterhouse, _Proc. Zool. Soc._ 1841, p. 91. + +[388] De Blainville, _Bull. Soc. Philom._ 1826, p. 62. + +[389] Wagler, _ibid._ p. 1219. + +[390] Andrew Smith, _S. African Quart. Journ._ vol. ii. p. 2 (1831). + +[391] Geoffroy, _Ann. du Muséum_, vol. vi. p. 81 (1805). + +[392] Desmarest, _Mém. Soc. d’Hist. Nat._ vol. i. p. 44 (1822). + +[393] For description and anatomy of this species see Dobson, _Proc. +Zool. Soc._ 1884, p. 233. + +[394] Temminck, _Monographies des Mammifères_, vol. i. p. 245 (1827). + +[395] Cuvier, _Ann. Sci. Nat._ sér. 2, vol. vi. p. 347 (1836). Amended. + +[396] Illiger, _Prodromus Syst. Mamm._ p. 90 (1811). + +[397] Desmarest, _Nouv. Dict. d’Hist. Nat._ vol. x. p. 45 (1817). Amended +from _Echimys_. + +[398] Wagner, _Wiegmann’s Archiv_, 1845, pt. 2, p. 145. + +[399] Geoffroy, _Ann. Sci. Nat._ sér. 2, vol. x. p. 126 (1838). + +[400] F. Cuvier, _Mammifères_, 6ᵐᵉ livr. (1829). + +[401] Waterhouse, _Nat. Hist. of Mamm._ vol. ii. p. 351 (1848). + +[402] F. Cuvier, _Dents des Mammifères_, p. 256 (1825). + +[403] F. Cuvier, _Mém. du Muséum_, vol. ix. p. 413 (1822). “Sinéthère.” + +[404] Gray, _Proc. Zool. Soc._ 1843, p. 21. + +[405] Linn. _Syst. Nat._ 12th ed. vol. i. p. 76 (1766). + +[406] Cuvier, _Règne-Animal_, 2d ed. vol. i. p. 215 (1829). “Atherure.” + +[407] Günther, _Proc. Zool. Soc._ 1876, p. 739. + +[408] Bennett, _Gardens, etc. Zool. Soc._ pt. i. p. i. (1829). + +[409] Meyer, _Nova Acta Ac. Cæs. Leop.-Car._ vol. xvi. p. 576 (1833). + +[410] Brooks, _Trans. Linn. Soc._ vol. xvi. p. 102 (1828). + +[411] Foster, _Second Rep. Geol. of Ohio_, p. 81 (1838). + +[412] Illiger, _Prodromus Syst. Mamm._ p. 93 (1811). + +[413] F. Cuvier, _Ann. du Muséum_, vol. x. p. 203 (1807). + +[414] Peters, _Monatsber. Ak. Berlin_, 1873, p. 551. + +[415] Pallas, _Misc. Zool._ p. 30 (1766); _ex_ Klein. + +[416] Desmarest, _Mammalogie_, p. 360 (1822). + +[417] Erxleben, _Syst. Règ. Animal_, p. 191 (1777); _ex_ Brisson. + +[418] Cuvier, _Tabl. Élément. de l’Hist. Nat._ p. 132 (1798). + +[419] Linn. _Syst. Nat._ 12th ed. vol. i. p. 77 (1766). + +[420] From the absence of the Common Hare in Scandinavia it is considered +probable that the name _L. timidus_ was really applied to the Mountain +Hare, and some writers accordingly use the name _L. europæus_ for the +former. + +[421] _Variations of Animals and Plants_, 2d ed. vol. i. p. 119. + +[422] The Feræ of Linnæus included all the then known species of the +modern orders Carnivora, Insectivora, and Marsupialia. + +[423] The tusks of the Walrus, altogether so aberrant in its dentition, +are partial exceptions to this statement, but in old individuals the +pulp-cavity fills up, and they cease to grow. + +[424] See Flower, “On the Value of the Characters of the Base of the +Cranium in the Classification of the Order _Carnivora_,” _Proc. Zool. +Soc._ 1869, p. 4; Mivart, “On the Classification and Distribution of +the _Æluroidea_,” _ibid._ 1882, pp. 135 and 459; see also _The Cat, an +Introduction to the Study of Backboned Animals, especially Mammals_, by +the same author, 1881. + +[425] Linn. _Syst. Nat._ 12th ed. vol. i. p. 60 (1766). + +[426] _The Cat_, pp. 392-426 (1881). + +[427] _Fauna of British India_, “Mammalia,” pp. 56-90 (1888). + +[428] _Zoology and Geology of Eastern Persia_ (1876). + +[429] See Blanford, _Fauna of British India_, “Mammalia,” p. 57 (1883). + +[430] _Transactions of the Zoological Society_, vol. i. p. 165 (1835). + +[431] _A Hunter’s Wanderings in Africa_, 1881, p. 258. + +[432] Mr. Selous, whose opportunities for obtaining evidence upon this +subject were very large, says that in the region of South Africa, +between the Zambesi and the Limpopo rivers, he never saw a lion with +any long hair under the body, and that the manes of the wild lions of +that district are far inferior in development to those commonly seen in +menageries in Europe. + +[433] _The Lion and the Elephant_, 1873, p. 19. + +[434] Hon. W. H. Drummond, _The Large Game and Natural History of South +and South-East Africa_, 1875, p. 278. + +[435] _Fauna of British India_, “Mammalia,” p. 59 (1888). + +[436] See W. T. Blanford, _Fauna of British India_, “Mammalia,” p. 69 +(1888). + +[437] _Monographs of the Palæontographical Society_, 1872. + +[438] Syn. _F. macrocelis_. + +[439] Syn. _F. maniculata_ and _caligata_. + +[440] Wagler, _Syst. Amphib._ etc. p. 30 (1830). + +[441] Bennett, _Trans. Zool. Soc._ vol. i. p. 137 (1833). + +[442] Linn. _Syst. Nat._ 12th ed. vol. i. p. 63 (1766). + +[443] Gray, _Proc. Zool. Soc._ 1864, p. 518. + +[444] Cuvier, _Règne-Animal_, vol. i. p. 156 (1817). + +[445] Horsfield, _Zool. Research. Java_ (1824).—_Prionodontidæ._ + +[446] Gray, _Proc. Zool. Soc._ 1864, p. 520. + +[447] F. Cuvier, _Hist. Nat. des Mammifères_, No. 186 (1821). + +[448] See W. T. Blanford, _Proc. Zool. Soc._ 1885, p. 780. + +[449] _Fauna of British India_, “Mammalia,” p. 108 (1888). + +[450] Gray, _Proc. Zool. Soc._ 1864, p. 542, _ex_ Petero. + +[451] Jourdan, _Comptes Rendus_, vol. v. p. 442 (1837). Amended. + +[452] Temminck, _Prospectus de Monographies des Mammifères_, March 1824; +_Monographies_, vol. i. p. xxi. (1827). + +[453] Gray, _List of Mamm. Brit. Mus._ p. 54 (1843). + +[454] Gray, _Proc. Zool. Soc._ 1836, p. 88. + +[455] Illiger, _Prodromus Syst. Mamm._ p. 135 (1811). + +[456] Gray, _Proc. Zool. Soc._ 1861, p. 308. + +[457] Peters, _Mith. Ges. Nat. Freunde Berlin_, 19th November 1850. + +[458] Ogilby, _Proc. Zool. Soc._ 1833, p. 48. + +[459] Gray, _Proc. Zool. Soc._ 1864, p. 573. + +[460] F. Cuvier, _Hist. Nat. des Mammifères_, No. 199 (1825). + +[461] Desmarest, “Tabl. Méth. Mamm.” in _Nouv. Dict. d’Hist. Nat._ vol. +xxiv. (1804). + +[462] Geoffroy, _Comptes Rendus_, 1837, p. 578. + +[463] Geoffroy, _Mag. de Zool._ 1839, pp. 27, 37. + +[464] Doyère, _Ann. Sci. Nat._ vol. iv. p. 281 (1835). + +[465] Jourdan, _Comptes Rendus_, 1837, p. 422. Amended. + +[466] Geoffroy, _Mém. du Muséum_, vol. xi. p. 354 (1824). + +[467] For Anatomy of _Proteles_ see Flower, _Proc. Zool. Soc._ 1869, p. +474. + +[468] Zimmermann, _Specimen Zoologiæ Geographicæ_, p. 365 (1777). + +[469] _Fauna of British India_, “Mammalia,” p. 133 (1888). + +[470] The anatomical peculiarities of _Hyæna crocuta_ have been fully +elucidated in a series of papers by Morrison Watson in the _Proceedings +of the Zoological Society_ for 1877, 1878, 1879, and 1881, in which +references to previous authors on the subject will be found. + +[471] Linn. _Syst. Nat._ 12th ed. vol. i. p. 56 (1766). + +[472] In Domestic Dogs a hallux is frequently developed, though often in +a rudimentary condition, the phalanges and claw being suspended loosely +in the skin, without direct connection with the other bones of the foot; +it is called by dog-fanciers the “dew claw.” + +[473] _Proc. Zool. Soc. Lond._, 1880, p. 238. See also Mivart, _Dogs, +Jackals, Wolves, and Foxes; a Monograph of the Canidæ_ (1890). + +[474] _Fauna of British India_, “Mammalia,” pp. 153, 154 (1888). + +[475] Brookes, _Griffith’s Animal Kingdom_, vol. v. p. 151 (1827). + +[476] Lund, _K. Danks. Vid. Selsk. Afhand._ vol. xi. p. 62 (1845). + +[477] Lichtenstein, _Wiegmann’s Archiv._ 1838, vol. i. p. 290. + +[478] _Arch. Mus. Lyon._ vol. iii. art. 1, p. 85 (1881). + +[479] _Proc. Amer. Phil. Soc._ vol. xviii. p. 452 (1880). + +[480] For full details of the Arctoidea see Mivart, _Proc. Zool. Soc._ +1885, p. 340. + +[481] Linn. _Syst. Nat._ 12th ed. vol. i. p. 69 (1766). + +[482] Meyer, _Uebersicht d. neu. Zool. Entdeckungen_, etc. p. 155 (1793). + +[483] A. Milne-Edwards, _Nouv. Arch. du Muséum_, vol. vii. _Bull._ p. 88 +(1871). Amended from “Ailuropus.” + +[484] F. Cuvier, _Hist. Nat. des Mammifères_ (1825). Amended from +“Ailurus.” For anatomy, see Flower, _Proc. Zool. Soc._, 1870, p. 752. + +[485] _Fauna of British India_, “Mammalia,” p. 189 (1888). + +[486] Storr, _Prodromus Meth. Mamm._ p. 35 (1780). + +[487] A corruption of the North American Indian “arrathkune” or +“arathcone.” The French _raton_ or _raton laveur_, German _Waschbär_, and +other European names are derived from a curious habit the Raccoon has of +dipping or washing its food in water before eating it. + +[488] Lichtenstein, _Isis_, 1831, p. 512. + +[489] Allen, _Proc. Ac. Nat. Sci. Philad._ 1876, p. 20. + +[490] Storr, _Prodromus Meth. Mamm._ p. 35 (1780). + +[491] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 127 (1811). + +[492] Also in two other species noticed below. One extinct Otter has two +upper molars. + +[493] Erxleben, _Syst. Règn. Animal_, p. 445 (1777). + +[494] See Thomas, _Proc. Zool. Soc._ 1889, p. 190. + +[495] The synonymy of this species is not settled, and the adoption of +the name given here only preliminary. + +[496] Gloger, _Nova Acta Ac. Cæs. Leop.-Car._ vol. xiii. pt. 2, p. 511 +(1827): Syn. _Enhydra_; Fleming, _Philosophy of Zoology_, vol. ii. p. 187 +(1822). Preoccupied by _Enhydris_, Merrem, _Tent. Syst. Amphib._ p. 140 +(1820). + +[497] Cuvier, “Tabl. de Classif.” in _Leçons d’Anat. Compar._ vol. i. +(1800). + +[498] Gray, _Ann. Mag. Nat. Hist._ ser. 2, vol. i. p. 581 (1837). + +[499] F. Cuvier, _Hist. Nat. des Mammifères_ (1825). + +[500] Possibly the name should be Bálu-soor (Sand-pig). + +[501] F. Cuvier, _Hist. Nat. des Mammifères_ (1825). + +[502] Storr, _Prodromus Meth. Mamm._ p. 34 (1780). + +[503] Waterhouse, _Proc. Zool. Soc._ 1838, p. 154. + +[504] Storr, _Prodromus Meth. Mamm._ p. 34 (1780). + +[505] Gray, _Proc. Zool. Soc._ 1831, p. 94. + +[506] Garrod, _ibid._ 1879, pl. xxix. + +[507] Kaup, _Thierreich_, vol. i. p. 352 (1835). + +[508] Bell, _Proc. Zool. Soc._ 1837, p. 45. + +[509] Linn. _Syst. Nat._ 12th ed. vol. i. p. 66 (1766). + +[510] By all old authors of authority, as Ray, Pennant, Shaw, and +Fleming, the word is written “Martin,” but this form of spelling is +now generally reserved by way of distinction for the bird. The term +“Marten-Cat,” often used, is a misnomer. + +[511] See Rolleston, “On the Domestic Cats, _Felis domesticus_ and +_Mustela foina_, of Ancient and Modern Times,” _Journal of Anatomy and +Physiology_, vol. ii. p. 47, 1868. + +[512] O. Thomas, _Ann. Mag. Nat. Hist._ ser. 5, vol. xi. p. 370 (1883). + +[513] Gervais, _Dict. Univ. d’Hist. Nat._ t. iv. p. 685 (1849). + +[514] Storr, _Prodromus Meth. Mamm._ p. 34 (1780). + +[515] _Proc. Zool. Soc._ 1885, p. 497. + +[516] Péron, _Voyage aux Terres Australes_, vol. ii. p. 37 note (1816). + +[517] “On the structure of Hooker’s Sea-Lion (_Arctocephalus hookeri_),” +_Trans. Zool. Soc._ vol. xii. p. 369 (1890). + +[518] Linn, _Syst. Nat._ 12th ed. vol. i. p. 49 (1766). + +[519] The former word is a modification of the Scandinavian _vallross_ or +_hvalros_ (“whale-horse”), the latter an adaptation of the Russian name +for the animal. + +[520] Nilsson, _Faun. Scandinav._ vol. i. p. 377 (1820). + +[521] Linn. _Syst. Nat._ 12th ed. vol. i. p. 55 (1766). + +[522] Fleming, _Philosophy of Zoology_, vol. ii. p. 187 (1822). + +[523] For details of these and the other genera see Mivart, _Proc. Zool. +Soc._ 1885, p. 486, _et seq._ + +[524] Peters, _Monatsb. K. P. Akad. Wissensch. zu Berlin_, p. 393 (1875), +substituted for _Stenorhynchus_, F. Cuvier; preoccupied for a genus of +Crustacea. + +[525] Gray, _Zoology of Erebus and Terror_, vol. i. p. 5 (1844). + +[526] New name, _Syn. Leptonyx_, Gray, _Charlesworth’s Mag. Nat. Hist._ +vol. i. p. 582 (1837); preoccupied by Swainson, 1821. + +[527] Gray, _Zoology of Erebus and Terror_, vol. i. p. 7 (1844). + +[528] Nilsson, _Faun. Scandinav._ vol. i. p. 382 (1820). + +[529] F. Cuvier, _Mém. du Muséum_, vol. xi. p. 200 (1824), “Macrorhine.” + +[530] Pallas, _Acta Acad. Sci. Imp. Petropolis_, vol. iv. pt. 1, p. 208 +(1780). + +[531] _Ueber die Säugethiergattung Galeopithecus._ _Sv. Ak. Handl._ vol. +xxi. pt. xi. (1886). + +[532] Raffles, _Trans. Linn. Soc._ vol. xiii. p. 256 (1822). + +[533] Gray, _Proc. Zool. Soc._ 1848, p. 23. + +[534] Andrew Smith, _S. African Quart. Journ._ vol. ii. No. 1, p. 64 +(1833). + +[535] The above correct formula of the dentition of this family has been +recently worked out by O. Thomas, _Proc. Zool. Soc._ 1890, pp. 445, 446. + +[536] Peters, _Bericht k. preuss. Ak. Wiss._ 1847, p. 36. + +[537] Horsfield and Vigors, _Zool. Journ._ vol. iii. p. 246 (1828). + +[538] Linn. _Syst. Nat._ 12th ed. vol. i. p. 75 (1766). + +[539] Originally given incorrectly as _Neurogymnurus_. + +[540] _Proc. Zool. Soc._ 1890, p. 49. + +[541] Linn. _Syst. Nat._ 12th ed. vol. i. p. 73 (1766). + +[542] Syn. _S. minutus_. + +[543] Blyth, _Journ. As. Soc. Bengal_, vol. xxiv. p. 36 (1855). + +[544] Coues, _Bull. U.S. Geol. Surv. Terrs._ vol. iii. p. 646 (1877). + +[545] Gray, _Proc. Zool. Soc._ 1837, p. 124. + +[546] Wagler, _Isis_, 1832, p. 275. + +[547] Gray, _Proc. Zool. Soc._ 1837, p. 124. + +[548] Wagler, _Isis_, 1832, p. 275. + +[549] Brandt, in _Lehmann’s Reise.-Zool. Anh._ p. 299 (1852). + +[550] Milne-Edwards, _Comptes Rendus_, vol lxx. p. 341 (1870). + +[551] Anderson, _Journ. As. Soc. Bengal_, vol. xlvi. p. 262 (1877). + +[552] Milne-Edwards, _Comptes Rendus_, vol. lxx. p. 341 (1870). + +[553] Cuvier, “Tabl. de Classif.” in _Leçons d’Anat. Compar._ vol. i. +(1800). + +[554] Temminck, _Fauna Japonica_, vol. i. p. 22 (1842). + +[555] Milne-Edwards, _Arch. du Muséum_, vol. vii. Bull. p. 92 (1872). + +[556] Cuvier, “Tabl. de Classif.” in _Leçon d’Anat. Comp._ vol. i. (1800). + +[557] Pomel, _Arch. Sci. Phys. Nat._ vol. ix. p. 247 (1848). + +[558] Illiger, _Prodromus Syst. Mamm. et Avium_. p. 125 (1811). + +[559] Milne-Edwards, _N. Arch. du Muséum_, vol. vii. Bull. p. 92 (1872). + +[560] Linn, _Syst. Nat._ 12th ed. p. 73 (1766). + +[561] The following account is taken almost entirely from Dr. Dobson. + +[562] Du Chaillu, _Proc. Boston Soc. Hist. Nat._ vol. vii. p. 363 (1860). + +[563] Milne-Edwards, _Ann. Sci. Nat._ vol. xv. p. 5 (1872). + +[564] Brandt, _Mém. Ac. Imp. St. Pétersbourg_, 1833, vol. ii. p. 459. + +[565] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 124 (1811). + +[566] Mivart, _Proc. Zool. Soc._ 1871, p. 72. + +[567] I. Geoffroy, _Ann. Sci. Nat._ sér. 2, vol. viii. p. 60 (1837). + +[568] Thomas, _Journ. Linn. Soc.—Zool._ vol. xvi. p. 319 (1882). + +[569] Grandidier, _Rev. and Mag. Zool._ 1870, p. 50. + +[570] Lacépède, _Mém. de l’Institut_, vol. iii. p. 493 (1801—read 1799). + +[571] _Proc. Zool. Soc._ 1888, p. 473. + +[572] Bennett, _Trans. Zool. Soc._ vol. ii. p. 38 (1835). + +[573] Geoffroy, _Ann. du Muséum_, vol. xv. p. 90 (1810).—_Ex._ Brisson. + +[574] Gray, _List. Spec. Mamm. Brit. Mus._ pp. 37, 38 (1843): Syn. +_Cynonycteris_. + +[575] Jentink, _Notes Leyd. Mus._ vol. i. p. 117 (1879).—Amended. + +[576] F. Cuvier, _Dents des Mammifères_, p. 39 (1825). + +[577] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 118 (1811). + +[578] Geoffroy, _Ann. du Muséum_, vol. xvi. p. 99 (1810). + +[579] O. Thomas, _Ann. Mag. Nat. Hist._ ser. 6, vol. i. p. 155 (1888). + +[580] Gray, _Proc. Zool. Soc._ 1859, p. 36. + +[581] Dobson, _Journ. As. Soc. Bengal_, vol. xlii. p. 204 (1873). + +[582] New name: Syn. _Macroglossus_, F. Cuvier, _Dents des Mammifères_, +p. 40 (1825). Preoccupied by _Macroglossum_, Scopoli, 1777. + +[583] Dobson, _Proc. Zool. Soc._ 1877, p. 119. + +[584] O. Thomas, _Ann. Mag. Nat. Hist._ ser. 5, vol. xix. p. 417 (1887). + +[585] Jentink, _Notes Leyd. Mus._ vol. xi. p. 209 (1889). + +[586] New name: Syn. _Megaloglossus_; Pagenstecher, _J. B. Mus. Hamburg_, +vol. ii. p. 125 (1885). Preoccupied by _Megaglossa_, Rond., 1865. + +[587] Geoffroy, _Nouv. Dict. d’Hist. Nat._ vol. xix. p. 383 (1803). + +[588] Gray, _Proc. Zool. Soc._ 1834, p. 53. The Bats of this genus are +usually described as _Phyllorhina_, but this use has been shown to be +incorrect; see Blanford, _Proc. Zool. Soc._ 1887, p. 637. + +[589] O. Thomas, _Ann. Mag. Nat. Hist._ ser. 6, vol. i. p. 156 (1888). + +[590] Gray, _Proc. Zool. Soc._ 1847, p. 16. + +[591] Dobson, _Journ. As. Soc. Bengal_, vol. xl. p. 455 (1871). + +[592] Blyth, _Journ. As. Soc. Bengal_, vol. xvii. p. 251 (1848). + +[593] Geoffroy, _Ann. du Muséum_, vol. xv. p. 197 (1810). + +[594] Geoffroy, _Nouv. Dict. d’Hist. Nat._ vol. xv. p. 501 (1803). + +[595] Geoffroy, _Descript. de l’Egypte_, vol. ii. p. 112 (1812). + +[596] Keyserling and Blasius, _Wirbelthiere Europ._ p. 55 (1840). + +[597] Peters, _Monatsber. Ak. Berlin_, 1859, p. 222. + +[598] Leach, _Trans. Linn. Soc._ vol. xiii. p. 78 (1822). + +[599] Allen, _Proc. Ac. Nat. Sci. Philad._ 1862, p. 247. + +[600] Keyserling and Blasius, _Wiegmann’s Archiv_, 1839, p. 312. + +[601] Peters, _Monatsber. Ak. Berlin_, 1866, p. 672. + +[602] Leach, _Trans. Linn. Soc._ vol. xiii. p. 71 (1822). + +[603] See O. Thomas, _Ann. Mus. Genova_ (2), vol. ix. pp. 84-88 (1890). + +[604] Rafinesque, _Journ. de Physique_, vol. lxxxviii. p. 417 (1819). + +[605] Rafinesque, _Précis des Decouvértes et Trav. Somiol._ p. 12 (1814). + +[606] Gray, _Ann. Mag. Nat. Hist._ vol. x. p. 259 (1842). + +[607] Linn. _Syst. Nat._ 12th ed. vol. i. p. 46 (1766). + +[608] Gray, _Ann. Mag. Nat. Hist._ vol. x. p. 258 (1842), _Kerivoula_. + +[609] Gray, _Mag. Zool. Bot._ vol. ii. p. 496 (1838). + +[610] Bonaparte, _Fauna Italica_, fasc. xxi. (1837). + +[611] Spix, _Sim. and Vesp. Bresil_, p. 61 (1823). + +[612] A. Milne-Edwards, _Bull. Soc. Philom._ sér. 7, vol. ii. p. 1 (1878). + +[613] Bonaparte, _Faun. Ital._ vol. i. (1832-41): Syn. _Furia_, F. +Cuvier, _Mém. du Muséum_, vol. xvi. p. 150 (1828). Preoccupied by Linn. +1766. + +[614] Peters, _Monatsber. Ak. Berlin_, 1877, p. 185. + +[615] Temminck (Van der Hoeven), _Tijdsch. Nat. Ges._ 1839, p. 22. + +[616] Peters, _Monatsber. Ak. Berlin_, 1867, p. 479. + +[617] Peters, _loc. cit._ p. 477. + +[618] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 121 (1811). + +[619] Geoffroy, _Descript. de l’Egypte_, vol. ii. p. 126 (1812). + +[620] Wied, _Isis_, 1819, p. 1629. + +[621] Linn. _Syst. Nat._ 12th ed. vol. i. p. 88 (1766). + +[622] Geoffroy, _Descript. de l’Egypte_, vol. ii. p. 123 (1812). + +[623] Horsfield, _Zool. Research Java_ (1824). + +[624] Geoffroy, _Ann. du Muséum_, vol. vi. p. 154 (1805). + +[625] Geoffroy, _Descript. de l’Egypte_, vol. ii. p. 114 (1812). + +[626] New name: Syn. _Mystacina_; Gray, _Voyage of the “Sulphur,”_ +“Mamm.” p. 23 (1843). Preoccupied by _Mystacina_, Boie, 1822. + +[627] Gray, _Ann. Mag. Nat. Hist._ vol. iv. p. 4 (1839). + +[628] Leach, _Trans. Linn. Soc._ vol. xiii. p. 76 (1820-22).—Amended. + +[629] Tomes, _Proc. Zool. Soc._ 1863, p. 81. + +[630] New name: Syn. _Macrotus_; Gray, _Proc. Zool. Soc._ 1843, p. 21. +Preoccupied by _Macrotis_, Dej. 1833. + +[631] New name: Syn. _Macrophyllum_; Gray, _Mag. Zool. Bot._ vol. ii. p. +489 (1838). Preoccupied by _Macrophylla_, Hope, 1837. + +[632] Leach, _Trans. Linn. Soc._ vol. xiii. pp. 74, 75 (1822). For the +references to the other genera see Dobson, _Cat. Chiropt. Brit. Mus._ + +[633] Gray, _Proc. Zool. Soc._ 1866, p. 113. Syn. _Schizostoma_; Gervais, +1855. Preoccupied by Broun, 1835. + +[634] New name: Syn. _Tylostoma_; Gervais, 1855. Preoccupied by Sharpe, +1849. + +[635] Gervais, Castlenau’s _Exped.-Zool._ p. 43 (1855): Syn. _Carollia_, +Gray, 1838. Preoccupied by _Carolia_, Cantraine, 1837. + +[636] The references to the genera of this and the following division +will be found in Dobson’s _Catalogue_. + +[637] New name: Syn. _Ischnoglossa_, Saussure, 1860. Preoccupied by +Kraatz, 1856. + +[638] Wied, _Beitr. Natgesch. Brasil_, vol. ii. p. 231 (1826). + +[639] Spix, _Sim. et Vesp. Brasil_, p. 68 (1823). + +[640] For the arguments in favour of placing the Lemurs in a separate +order see Milne-Edwards, “Observations sur quelques points de +l’embryologie des Lemuriens et sur les affinités zoologiques de ces +animaux,” in the _Ann. des Sciences Nat._ October 1871; and P. Gervais, +“Encephale des Lemures,” in _Journ. de Zoologie_, tom. i. p. 7. For those +for retaining them among the Primates, see Mivart, “On _Lepilemur_ and +_Chirogaleus_, and on the Zoological Rank of the Lemuroidea,” in _Proc. +Zool. Soc._ 1873, p. 484. + +[641] Geoffroy, _Mag. Encyclop._ 2d ann. vol. i. p. 46 (1796), “Indri.” + +[642] Bennett, _Proc. Zool. Soc._ 1832, p. 20. + +[643] Jourdan, _Mém. de l’Institut_, vol. ii. p. 231 (1834). + +[644] Linn. _Syst. Nat._ 12th ed. vol. i. p. 44 (1766). + +[645] _Proc. Zool. Soc._ 1879, p. 132. + +[646] Gray, _Proc. Zool. Soc._ 1870, p. 829. + +[647] I. Geoffroy, _Cat. Mus. Hist. Nat. Paris_, p. 75 (1851). Amended +from _Lepilemur_. + +[648] _Monatsb. Ak. Berlin_, 1874, p. 690. + +[649] Geoffroy, _Ann. du Muséum_, vol. xix. p. 171 (1812). + +[650] Geoffroy, _Mag. Encyclop._ 2d ann. vol. i. p. 49 (1796). + +[651] Geoffroy, _Ann. du Muséum_, vol. xix. pp. 162, 163 (1812). + +[652] For the anatomy of this genus, see J. L. C. Shroeder van der Kolk +and W. Vrolik, “Recherches d’Anatomie comparée sur le genre _Stenops_ +d’Illiger,” in _Bijdragen tot de Dierkunde_, Part 1, Amsterdam, 1848-54. + +[653] Geoffroy, _Mag. Encyclop._ 2d ann. vol. i. p. 48 (1796). + +[654] _Mammalia of British India_, p. 48 (1888). + +[655] Bennett, _Proc. Zool. Soc._ 1839, p. 109. + +[656] For the anatomy of _P. potto_, see Van der Hoeven and Van Campen +(_Ontleedkundige Onderzoek van den Potto van Bosman_, 1859) for _P. +calabarensis_, Huxley, _Proc. Zool. Soc._ 1864, p. 314. + +[657] Storr, _Prodromus Meth. Mamm._ (1780). + +[658] H. Burmeister, _Beiträge zur nähreren Kenntniss der gattung +Tarsius_, 1846. + +[659] Cuvier, “Table de Class.” in _Leçons d’Anat. Comp._ vol. i. (1800). + +[660] It was first named _Daubentonia_ by Geoffroy; but this name +was withdrawn by its author in favour of _Chiromys_, as it had been +previously given to a genus in the vegetable kingdom. This would not, +however, constitute preoccupation according to the modern rules of +nomenclature. + +[661] R. Owen, “On the Aye-aye,” in _Trans. Zool. Soc._ 1862, vol. v. +p. 33; W. Peters, “Ueber die Säugethiergattung _Chiromys_,” in _Abhand. +Königl. Akad. der Wissenschaften_, Berlin, 1865, p. 79. + +[662] One specimen has been seen with only three lower premolars. + +[663] Article Ape, _Encyclopædia Britannica_, ninth edition. + +[664] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 71 (1811). + +[665] Geoffroy, _Ann. du Muséum_, vol. xix. p. 120 (1812). + +[666] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 70 (1811). + +[667] Geoffroy, _Ann. du Muséum_, vol. xix. p. 115 (1812). + +[668] Gray, _Proc. Zool. Soc._ 1849, p. 9. Amended from _Ouakaria_: Syn. +_Brachyurus_; Spix, _Sim. et Vesp. Brasil_, p. 11 (1823). Preoccupied by +Fischer, 1814. + +[669] Geoffroy, _Ann. du Muséum_, vol. xix. p. 112 (1812). + +[670] Kaup, _Thierreich_, vol i. p. 51 (1835). + +[671] Spix, _Sim. et Vesp. Brasil_, p. 25 (1823). + +[672] Geoffroy, _Ann. du Muséum_, vol. vii. p. 260 (1806). + +[673] I. Geoffroy, _Dict. Class._ vol. xv. p. 443 (1829). + +[674] Geoffrey, _Ann. du Muséum_, vol. xix. p. 106 (1812). + +[675] Erxleben, _Syst. Règne Animal_, p. 44 (1777). + +[676] Lacépède, “Nouv. tabl. méth.” (1799) in _Mém. de l’Institut_, vol. +iii. p. 490 1801. + +[677] “‘Mandrill’ seems to signify a ‘man-like Ape,’ the word ‘Drill’ +or ‘Dril’ having been anciently employed in England to denote an Ape or +Baboon. Thus in the fifth edition of Blount’s ‘_Glossographia_, or a +dictionary interpreting the hard words of whatsoever language now used +in our refined English tongue ... very useful for all such as desire +to understand what they read,’ published in 1681, I find ‘Dril, a +stonecutter’s tool wherewith he bores little holes in marble, etc. Also a +large overgrown Ape and Baboon, so called.’ ‘Drill’ is used in the same +sense in Charlton’s _Onomasticon Zoicon_, 1668. The singular etymology of +the word given by Buffon seems hardly a probable one.”—Huxley’s _Man’s +Place in Nature_, p. 10, 1863. + +[678] I. Geoffroy, _Arch. du Muséum_, vol. ii. p. 576 (1841). + +[679] I. Geoffroy, _Voyage de Belanger_, p. 66 (1834). + +[680] Lacépède, _Mém. de l’Institut_, vol. iii. p. 450 (1801). Amended. + +[681] Geoffroy, _Ann. du Muséum_, vol. xix. p. 97 (1812). + +[682] Erxleben, _Syst. Règne. Animal_, p. 22 (1777). + +[683] Or _Colobinæ_. + +[684] Geoffroy, _Ann. du Muséum_, vol. xix. p. 90 (1812). + +[685] F. Cuvier, _Hist. Nat. des Mammifères_ (1821), “Semno-pithèque.” + +[686] Separated generically by some writers as _Rhinopithecus_. + +[687] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 69 (1811). + +[688] Wagner, _Gelehrte Anzeigen_, vol. viii. No. 38, p. 310 (1839). + +[689] Depéret, _Comptes Rendus_, vol. cix. p. 982 (1889); see also _Mém. +Soc. Géol. France_, “Palæontologie,” vol. i. (1890). + +[690] Gervais, _Comptes Rendus_, vol. lxxiv. p. 1217 (1872). + +[691] Scimmie Fossili Italiane, _Boll. Comm. Geol._ 1890. + +[692] Illiger, _Prodromus Syst. Mamm. et Avium_, p. 67 (1811). + +[693] Linn. _Syst. Nat._ 12th ed. vol. i. p. 34 (1766). + +[694] A Malay word, signifying “Man of the Woods.” + +[695] One skeleton in the Museum of the Royal College of Surgeons has +five lumbar vertebræ, and has thus given rise to the statement that the +number of vertebræ in the Orang is the same as in Man. + +[696] I. Geoffroy, _Comptes Rendus_, vol. xxxiv. p. 84 (1852). + +[697] De Blainville, _Leçons Orales_ (1839). The Chimpanzees have been +very generally described under the name of _Troglodytes_, but since this +name is preoccupied for a genus of birds, it is incumbent to follow the +strict rule, and adopt the name _Anthropopithecus_, although both the +present writers have elsewhere expressed the opposite opinion. + +[698] Lartet, _Comptes Rendus_, vol. xliii. p. 219 (1856). + +[699] _Mém. Soc. Géol. France_, “Palæontologie,” vol. i. Mém. No. 1 +(1890). + +[700] _Man’s Place in Nature_, 1863, and _Anatomy of Vertebrated +Animals_, 1871. See also the more recent investigations of Broca into the +comparative structure of Man and the higher Apes, published mostly in the +_Revue d’Anthropologie_. + +[701] “On the Classification of the Varieties of the Human Species,” by +W. H. Flower, _Journal of the Anthropological Institute of Great Britain +and Ireland_, May 1885. + +[702] The Malay of Blumenbach was a strange conglomeration of the then +little known Australian, Papuan, and true Malay types. + +[703] No one can have seen a group of Botocudos from Brazil or of +natives of Tierra del Fuego without being struck by their markedly +Mongolian external characteristics. + + + + +INDEX + + + Aard-Wolf, 540 + + Aard-Vark, 211 + + Absorbent system, 63 + + _Acanthoglossus_, 125 + + _Acanthomys_, 476 + + _Aceratherium_, 411 + + _Achænodon_, 292 + + _Achyrodon_, 114 + + _Acrobates_, 155 + + _Acrotherium_, 440 + + _Adapis_, 697 + + _Adapisorex_, 634 + + _Adapisoricidæ_, 634 + + _Adapisoriculus_, 634 + + _Addax_, 345 + + _Adenota_, 339 + + _Adinotherium_, 440 + + _Ælurictis_, 524 + + _Ælurodon_, 562 + + _Æluroidea_, 501 + + _Æluropus_, 560 + + _Ælurus_, 562 + + _Æpyceros_, 341 + + _Æpyprymnus_, 164 + + _Agabelus_, 260 + + Agouti, 488 + + _Agriochœrus_, 293 + + Ai, 182 + + Air-sacs, 68 + + _Alactaga_, 480 + + Albinism, 10 + + _Alcelaphus_, 334 + + _Alces_, 326 + + Allantois, 77 + + _Allodon_, 111 + + _Allops_, 413 + + Allotheria, 109 + + Alpaca, 303 + + _Amblotherium_, 114 + + Amblypoda, 436 + + _Amorphochilus_, 666 + + _Amphictis_, 539 + + _Amphicyon_, 555 + + _Amphidozotherium_, 634 + + _Amphilestes_, 114 + + _Amphiperatherium_, 135 + + _Amphisorex_, 628 + + _Amphitherium_, 114 + + _Amphitragulus_, 330 + + _Amynodon_, 412 + + _Anaptomorphus_, 697 + + _Anchilophus_, 376 + + _Anchippodus_, 441 + + _Anchitherium_, 376 + + Ancylopoda, 413 + + _Ancylotherium_, 413 + + _Anoa_, 361 + + _Anomaluridæ_, 449 + + _Anomalurus_, 449 + + _Anoplotheriidæ_, 293 + + _Anoplotherium_, 294 + + Anteater, 191 + Scaly, 205 + + Antebrachium, 47 + + _Antechinomys_, 139 + + Antelopes, 334 + + _Anthops_, 657 + + _Anthorhina_, 674 + + _Anthracotheriidæ_, 292 + + Anthropoidea, 699 + + _Anthropopithecus_, 736 + + _Antilocapra_, 333 + + _Antilocapridæ_, 333 + + _Antilope_, 340 + + Antlers, 308 + + _Antrozous_, 661 + + _Anurosorex_, 626 + + Aoudad, 356 + + Apar, 199 + + Ape, 699 + + _Aphelops_, 411 + + _Aphelotherium_, 697 + + _Archælurus_, 524 + + Archæoceti, 246 + + _Archæomys_, 484 + + _Archizonurus_, 157 + + _Arctictis_, 534 + + _Arctocebus_, 693 + + _Arctocephalus_, 595 + + _Arctocyon_, 609 + + _Arctocyonidæ_, 609 + + _Arctogale_, 533 + + Arctoidea, 556 + + Arctomyinæ, 454 + + _Arctomys_, 454 + + _Arctonyx_, 574 + + _Arctotherium_, 561 + + Argali, 355 + + Armadillo, 195 + + _Artibeus_, 676 + + Artiodactyla, 275 + + _Arvicola_, 466 + + Arvicolinæ, 465 + + Ass, 383 + + _Atalapha_, 663 + + _Ateles_, 715 + + _Atherura_, 487 + + _Auchenia_, 298 + + _Aulacodus_, 483 + + _Aulaxinuus_, 723 + + Aurochs, 367 + + Australasian region, 102 + + _Avahis_, 686 + + Axis, 320 + + Aye-aye, 695 + + + _Babirusa_, 287 + + Baboon, 719 + + _Bachitherium_, 307 + + Badger, 575 + American, 576 + Sand, 575 + + _Balæna_, 236 + + _Balænidæ_, 234 + + _Balænodon_, 251 + + Balænoidea, 234 + + _Balænoptera_, 242 + + _Balænotus_, 240 + + Bandicoot, 141 + + Banteng, 365 + + _Bassaricyon_, 566 + + _Bassaris_, 566 + + Bats, 641 + + _Bathyergus_, 478 + + _Bdeogale_, 537 + + Bear, 558 + + Beaver, 458 + + Beisa, 343 + + Beluga, 262 + + _Berardius_, 256 + + _Bettongia_, 163 + + Bharal, 356 + + _Bibos_, 360 + + Bighorn, 355 + + Binturong, 534 + + Bison, 362 + + Black-Fish, 269 + + Bladder, 69 + + _Blarina_, 624 + + _Blastomeryx_, 330 + + Blaubok, 343 + + Blessbok, 335 + + Blood, 63 + + _Bolodon_, 111 + + _Boncia_, 653 + + Bontebok, 334 + + Bosch-Vark, 286 + + _Boselaphus_, 345 + + _Bothriolabis_, 291 + + Bottlenose, 253, 270 + + _Bovidæ_, 334 + + Brachium, 47 + + _Brachyphylla_, 675 + + _Brachytarsomys_, 465 + + _Brachyurus_, 712 + + _Bradypodidæ_, 179 + + _Bradypus_, 181 + + Brain, 69 + + _Bramatherium_, 333 + + Brocket, 330 + + _Brontotherium_, 413 + + Bruta, 176 + + _Bubalus_, 361 + + _Budorcas_, 351 + + Buffalo, 361 + + Bush-dog, 553 + + + Cachalot, 249 + + _Cadurcotherium_, 412 + + Cæcum, 59 + + _Cælogenys_, 489 + + _Cænopithecus_, 696 + + _Cænotheriidæ_, 294 + + _Cænotherium_, 294 + + _Callinycteris_, 655 + + _Callithrix_, 713 + + _Callophoca_, 606 + + _Calomys_, 463 + + _Caloprymnus_, 164 + + _Calotragus_, 339 + + Camel, 296 + + _Camelidæ_, 295 + + _Camelus_, 296 + + _Canidæ_, 544 + + _Canis_, 546 + + _Capra_, 352 + + _Capreolus_, 327 + + _Capromys_, 482 + + Capybara, 491 + + Caracal, 518 + + _Cardiatherium_, 491 + + _Cardiomys_, 491 + + _Cariacus_, 329 + + Caribou, 324 + + Carnivora, 496 + + _Carollia_, 674 + + _Carponycteris_, 654 + + Carpus, 48 + + _Carterodon_, 484 + + _Castor_, 457 + + _Castoridæ_, 457 + + _Castoroididæ_, 488 + + _Castoroides_, 488 + + Cat, 517 + + _Cavia_, 489 + + _Caviidæ_, 489 + + Cavy, 490 + + _Cayluxotherium_, 621 + + _Cebidæ_, 711 + + _Cebochœrus_, 292 + + _Cebus_, 717 + + Cement, 15 + + _Centetes_, 637 + + _Centetidæ_, 637 + + _Centurio_, 676 + + _Cephalogale_, 562 + + _Cephalophus_, 338 + + _Cephalorhynchus_, 266 + + _Cephalotes_, 653 + + _Cercocebus_, 723 + + _Cercoleptes_, 567 + + _Cercomys_, 483 + + _Cercopithecidæ_, 718 + + _Cercopithecus_, 724 + + _Cerivoula_, 664 + + _Cervalces_, 327 + + _Cervicapra_, 340 + + _Cervidæ_, 313 + + _Cervinæ_, 316 + + _Cervulus_, 316 + + _Cervus_, 319 + + _Cetacea_, 225 + + _Cetotherium_, 245 + + _Chænohyus_, 291 + + _Chætomys_, 486 + + _Chalcochloris_, 639 + + _Chalicomys_, 458 + + _Chalicotheriidæ_, 413 + + _Chalicotherium_, 413 + + _Chalinolobus_, 662 + + Chamois, 349 + + _Champsodelphis_, 259 + + Cheeta, 523 + + Chevrotain, 305 + Water, 306 + + _Chilonycteris_, 672 + + _Chimarrogale_, 626 + + Chimpanzee, 736 + + _Chinchilla_, 487 + + _Chinchillidæ_, 487 + + _Chirogaleus_, 689 + + _Chiromeles_, 669 + + _Chiromyidæ_, 694 + + _Chiromys_, 695 + + _Chironectes_, 134 + + Chiroptera, 641 + + Chiru, 341 + + _Chiruromys_, 476 + + _Chlamydophorinæ_, 196 + + _Chlamydophorus_, 196 + + _Chlamydotherium_, 201 + + _Chœronycteris_, 674 + + _Chœropotamidæ_, 292 + + _Chœropotamus_, 292 + + _Chœropsis_, 280 + + _Chœropus_, 143 + + _Cholœpus_, 182 + + Chorion, 77 + + _Chrysochloridæ_, 638 + + _Chrysochloris_, 639 + + _Chrysothrix_, 714 + + _Cimoliomys_, 113 + + Circulation, 63 + + Civet, 526 + Palm, 532 + + Classification, 84, 88 + + _Claviglis_, 460 + + Claws, 12 + + Coati, 566 + + _Cobus_, 339 + + _Cœlodon_, 184 + + _Cœlops_, 658 + + _Cogia_, 250 + + _Coleüra_, 667 + + _Colobus_, 727 + + Colour, 8 + + _Comphotherium_, 621 + + Condylarthra, 438 + + _Condylura_, 630 + + _Conepatus_, 574 + + _Connochætes_, 336 + + _Contracavia_, 491 + + _Coryphodon_, 437 + + _Coryphodontidæ_, 438 + + Cotylophora, 307 + + _Cotylopidæ_, 293 + + _Cotylops_, 293 + + Coypu, 482 + + Cranium, 35 + + _Crassitherium_, 223 + + Creodonta, 606 + + _Cricetodipus_, 479 + + _Cricetodon_, 464 + + _Cricetomys_, 477 + + _Cricetus_, 463 + + _Criotherium_, 349 + + _Crocidura_, 626 + + _Crossarchus_, 537 + + _Crossopus_, 625 + + Crusta Petrosa, 15 + + _Cryptophractus_, 201 + + _Cryptopithecus_, 699 + + _Cryptoprocta_, 525 + + _Ctenacodon_, 112 + + _Ctenodactylus_, 481 + + _Ctenomys_, 482 + + _Cuniculus_, 470 + + _Cuscus_, 149 + + _Cyclopidius_, 293 + + _Cycloturus_, 193 + + _Cynælurus_, 523 + + _Cynictis_, 537 + + _Cynocephalus_, 719 + + _Cynodictis_, 555 + + _Cynogale_, 534 + + _Cynohyænodon_, 608 + + Cynoidea, 544 + + _Cynomys_, 455 + + _Cynonycteris_, 652 + + _Cynopithecus_, 722 + + _Cynopterus_, 653 + + _Cyon_, 551 + + _Cystophora_, 605 + + + _Dacrytherium_, 294 + + _Dactylomys_, 483 + + _Dactylopsila_, 152 + + _Damalis_, 351 + + _Daphœnus_, 555 + + _Dasymys_, 462 + + _Dasypodidæ_, 194 + + _Dasypodinæ_, 197 + + _Dasypotherium_, 201 + + _Dasyprocta_, 488 + + _Dasyproctidæ_, 488 + + _Dasypus_, 197 + + _Dasyuridæ_, 136 + + _Dasyurus_, 138 + + _Daubentonia_, 695 + + Deer, 317, 319 + + _Delphinapterus_, 262 + + _Delphinidæ_, 260 + + Delphinoidea, 247 + + _Delphinus_, 271 + + _Dendrohyrax_, 418 + + _Dendrolagus_, 165 + + _Dendromys_, 463 + + Dental system, 13 + + Dentine, 14 + + _Deomys_, 473 + + Dermoptera, 614 + + Desman, 629 + + _Desmodus_, 677 + + _Desmotylus_, 223 + + Diaphragm, 67 + + _Diceratherium_, 411 + + _Dichobunus_, 294 + + _Dichodon_, 294 + + _Dichodontidæ_, 294 + + _Diclidurus_, 668 + + _Dicolpomys_, 484 + + _Dicotyles_, 289 + + _Dicotylidæ_, 289 + + Didelphia, 128 + + _Didelphyidæ_, 133 + + _Didelphys_, 134 + + _Didymictis_, 539 + + Digestive system, 53 + + _Dinictis_, 523 + + _Dinoceras_, 437 + + _Dinocyon_, 556 + + _Dinomyidæ_, 489 + + _Dinomys_, 489 + + _Dinotheriidæ_, 435 + + _Dinotherium_, 435 + + _Dinoziphius_, 251 + + _Diobroticus_, 458 + + _Dioplotherium_, 223 + + _Diphylla_, 678 + + Diphyodont, 20 + + Diplarthra, 275 + + _Diplomesodon_, 626 + + _Dipodidæ_, 479 + + _Dipodomys_, 479 + + _Dipodops_, 479 + + _Diprotodon_, 171 + + Diprotodontia, 144 + + _Diprotodontidæ_, 171 + + _Dipus_, 480 + + _Distœchurus_, 155 + + _Dœdicurus_, 203 + + Dog, 551 + + _Dolichophyllum_, 673 + + _Dolichopithecus_, 728 + + _Dolichotis_, 490 + + Dolphin, 270 + + _Dorcatherium_, 306 + + _Dorcopsis_, 166 + + Dormouse, 459 + + Douroucouli, 714 + + _Dremotherium_, 330 + + _Dromatherium_, 113 + + _Dromicia_, 154 + + _Dryolestes_, 114 + + _Dryopithecus_, 738 + + Duck-bill, 120 + + Ductless glands, 65 + + Dugong, 221 + + Duikerbok, 338 + + Duplicidentata, 491 + + + _Echidna_, 125 + + _Echidnidæ_, 124 + + _Echinogale_, 634 + + _Echinomys_, 483 + + _Echinothrix_, 477 + + Edentata, 176 + + Effodientia, 178 + + Eland, 348 + + _Elaphodus_, 318 + + _Elasmognathus_, 371 + + _Elasmotherium_, 411 + + _Eleotragus_, 340 + + Elephant, 424 + + _Elephantidæ_, 423 + + _Elephas_, 424 + + _Eleutherocercus_, 203 + + _Eliomys_, 459 + + _Eliurus_, 465 + + Elk, 326 + + _Ellobius_, 472 + + _Elotherium_, 292 + + _Emballonura_, 667 + + _Emballonuridæ_, 666 + + Enamel, 15 + + _Enhydra_, 570 + + _Enhydriodon_, 570 + + _Enhydrocyon_, 562 + + Entomophaga, 178 + + _Eohippus_, 374 + + _Eomys_, 464 + + _Eonycteris_, 654 + + _Eotherium_, 224 + + _Epiblema_, 488 + + Epiglottis, 67 + + _Epihippus_, 374 + + _Epomophorus_, 650 + + _Eporeodon_, 293 + + _Equidæ_, 376 + + _Equus_, 381 + + _Erethizon_, 484 + + _Ericulus_, 638 + + _Erinaceidæ_, 619 + + _Erinaceus_, 620 + + _Eriodes_, 715 + + Ermine, 590 + + _Eschatius_, 303 + + Ethiopian region, 98 + + _Eucastor_, 458 + + _Eucetus_, 251 + + _Eupetaurus_, 454 + + _Eupleres_, 538 + + _Euryceros_, 346 + + _Euryurus_, 203 + + _Eusmilus_, 524 + + _Eutatus_, 201 + + Eutheria, 173 + + _Evotomys_, 467 + + Eye, 72 + + + Fallow Deer, 323 + + _Felidæ_, 502 + + _Felis_, 502 + + _Felsinotherium_, 223 + + Fennec, 553 + + _Fennecus_, 553 + + _Feresia_, 270 + + _Fiber_, 470 + + Flying Fox, 651 + Lemur, 615 + Squirrel, 453 + + Foot, 52 + + _Fossa_, 527 + + Foussa, 525 + + Fox, 552 + + Fox-Bat, 651 + + _Furia_, 666 + + _Furipterus_, 666 + + + _Galago_, 690 + + _Galeopithecidæ_, 614 + + _Galeopithecus_, 614 + + _Galera_, 579 + + _Galictis_, 579 + + _Galidea_, 538 + + _Galidictis_, 538 + + Gaur, 365 + + Gayal, 365 + + _Gazella_, 341 + + _Gelocus_, 294 + + Gemsbok, 343 + + Genet, 528 + + _Genetta_, 528 + + _Geogale_, 635 + + Geographical distribution, 93 + + Geological distribution, 107 + + _Geomyidæ_, 478 + + _Geomys_, 478 + + _Georychus_, 478 + + Gerbillinæ, 462 + + _Gerbillus_, 462 + + Gibbon, 728 + + _Giraffa_, 331 + + _Giraffidæ_, 330 + + Glands, 12 + + _Glauconycteris_, 662 + + _Globicephalus_, 268 + + _Glossonycteris_, 674 + + Glossophaga, 674 + + Glutton, 591 + + _Glyptodon_, 203 + + _Glyptodontidæ_, 202 + + Gnu, 336 + + _Golunda_, 476 + + Goat, 352 + + Gopher, 478 + + Goral, 351 + + _Gorilla_, 734 + + Grampus, 267 + + _Grampus_, 270 + + _Graphiurus_, 459 + + Greenland Whale, 236 + + _Grimmia_, 338 + + _Grisonia_, 579 + + Ground Sloth, 184 + + _Gryphoca_, 606 + + _Grypotherium_, 189 + + Guanaco, 301 + + Guib, 347 + + Guinea-Pig, 490 + + _Gulo_, 591 + + _Gymnobelideus_, 154 + + _Gymnoptychus_, 454 + + _Gymnura_, 619 + + + _Habrocoma_, 482 + + _Habrothrix_, 464 + + Hair, 7 + + _Halichœrus_, 601 + + _Halicore_, 220 + + _Halicoridæ_, 220 + + _Halitheriidæ_, 222 + + _Halitherium_, 222 + + _Hallomys_, 465 + + Hamster, 463 + + _Hapale_, 710 + + _Hapalemur_, 689 + + _Hapalidæ_, 709 + + _Hapalotis_, 476 + + _Haploceros_, 351 + + _Haplodon_, 457 + + _Haplodontidæ_, 457 + + Hare, 492 + + _Harpyia_, 653 + + _Harpyiocephalus_, 663 + + Harte-beest, 335 + + Hearing, 73 + + Heart, 63 + + Hedgehog, 620 + + _Helicophora_, 340 + + _Helictis_, 578 + + _Heliophobius_, 478 + + _Helladotherium_, 333 + + _Helogale_, 537 + + _Hemiauchenia_, 303 + + _Hemicentetes_, 637 + + _Hemiderma_, 674 + + _Hemigale_, 533 + + _Hemigalidea_, 538 + + _Hemitragus_, 354 + + _Herpestes_, 535 + + _Herpetocetus_, 245 + + _Herpetotherium_, 135 + + _Heterocephalus_, 478 + + _Heterocetus_, 245 + + Heterodont, 23 + + _Heterohyrax_, 418 + + _Heteromys_, 479 + + _Hipparion_, 380 + + _Hippodactylus_, 381 + + _Hippohyus_, 291 + + _Hippopotamidæ_, 278 + + _Hippopotamus_, 278 + + _Hipposiderus_, 657 + + _Hippotigris_, 384 + + _Hippotragus_, 343 + + _Holochilus_, 464 + + _Holomeniscus_, 303 + + _Homalodontotherium_, 412, 414 + + _Hominidæ_, 740 + + _Homo_, 739 + + Homodont, 22 + + Hoofs, 12 + + Hoolock, 729 + + _Hoplocetus_, 251 + + _Hoplophoneus_, 524 + + _Hoplophorus_, 202 + + Horns, 310 + + Horse, 382 + + Hunting dog, 553 + + _Hyæna_, 540 + + _Hyænarctus_, 561 + + _Hyænidæ_, 540 + + _Hyænocyon_, 562 + + _Hyænodon_, 608 + + _Hyænodontidæ_, 608 + + _Hydaspitherium_, 333 + + _Hydrochœrus_, 490 + + Hydromyinæ, 461 + + _Hydromys_, 461 + + _Hydropotes_, 328 + + _Hylobates_, 728 + + _Hylomys_, 619 + + Hyoid, 39 + + _Hyomoschus_, 306 + + _Hyopotamus_, 292 + + _Hyopsodus_, 698 + + _Hyotherium_, 291 + + _Hypertragulus_, 307 + + _Hypogeomys_, 465 + + _Hypsiprymnodon_, 162 + + _Hypsiprymnodontinæ_, 162 + + _Hypsiprymnopsis_, 111 + + _Hypsiprymnus_, 163 + + _Hyrachyus_, 373 + + _Hyracidæ_, 415 + + _Hyracodon_, 412 + + _Hyracodontotherium_, 439 + + Hyracoidea, 415 + + _Hyracotherium_, 373 + + _Hyrax_, 417 + + _Hystricidæ_, 484 + + Hystricomorpha, 480 + + _Hystrix_, 486 + + + Ibex, 353 + + Ichneumon, 535 + + _Icticyon_, 553 + + _Ictitherium_, 539 + + _Ictonyx_, 579 + + _Ictops_, 640 + + _Indris_, 684 + + _Indrodon_, 699 + + _Inia_, 259 + + Insectivora, 610 + + Intestine, 59 + + _Inuus_, 723 + + _Ischnoglossa_, 674 + + _Isectolophus_, 374 + + _Issiodoromys_, 491 + + Ivory, 14 + + _Ixacanthus_, 259 + + + Jackal, 550 + + Jaguar, 521 + + Jerboa, 480 + + + Kangaroo, 159 + + _Kerivoula_ = _Cerivoula_ + + Kidney, 69 + + Killer, 267 + + Kinkajou, 567 + + Koala, 156 + + _Koalemus_, 157 + + _Kobus_ = _Cobus_ + + _Kogia_ = _Cogia_ + + Kudu, 348 + + Kusimanse, 538 + + + _Lagenorhynchus_, 270 + + _Lagidium_, 488 + + _Lagomyidæ_, 491 + + _Lagomys_, 491 + + _Lagorchestes_, 166 + + _Lagostomus_, 488 + + _Lagostrophus_, 165 + + _Lagothrix_, 716 + + _Lambdotheriidæ_, 413 + + _Lambdotherium_, 413 + + Langur, 727 + + _Lantanotherium_, 618 + + Larynx, 67 + + _Lasionycteris_, 661 + + _Latax_, 570 + + Leg, 51 + + Lemming, 467 + + _Lemur_, 687 + + _Lemuridæ_, 683 + + Lemuroidea, 682 + + Leopard, 514 + + _Lepidolemur_, 689 + + _Leporidæ_, 492 + + _Leptictidæ_, 640 + + _Leptictis_, 640 + + _Leptobos_, 367 + + _Leptomeryx_, 307 + + _Leptonycteris_, 674 + + _Leptonyx_, 605 + + _Leptotragulus_, 304 + + _Lepus_, 492 + + _Lestodon_, 189 + + _Leucocyon_, 553 + + _Limnosyops_, 413 + + Linsang, 530 + + Lion, 504 + + _Liotomus_, 113 + + _Listriodon_, 291 + + Liver, 60 + + Llama, 299, 302 + + _Lobodon_, 605 + + _Loncheres_, 483 + + _Lonchoglossa_, 674 + + _Lonchorhina_, 673 + + _Lophiodon_, 373 + + _Lophiodontidæ_, 373 + + _Lophiomeryx_, 294 + + _Lophiomyidæ_, 460 + + _Lophiomys_, 460 + + _Lophiotherium_, 374 + + _Lophocetus_, 259 + + _Lophostoma_, 673 + + Loricata, 179 + + _Loris_, 692 + + _Loxolophodon_, 437 + + Lungs, 68 + + _Lutra_, 567 + + _Lycalopex_, 552 + + _Lycaon_, 553 + + Lymphatics, 65 + + _Lyncodon_, 590 + + Lynx, 518 + + + _Macacus_, 722 + + _Machærodus_, 524 + + _Macrauchenia_, 414 + + _Macraucheniidæ_, 414 + + _Macroglossus_, 654 + + _Macrophyllum_, 673 + + _Macropodidæ_, 158 + + _Macropodinæ_, 164 + + _Macropus_, 167 + + _Macrorhinus_, 606 + + _Macroscelides_, 618 + + _Macroscelididæ_, 618 + + _Macrotherium_, 413 + + _Macrotus_, 673 + + _Malacomys_, 462 + + Mammary glands, 75 + + Mammoth, 428 + + Man, 739 + + Manatee, 215 + + _Manatidæ_, 215 + + _Manatus_, 215 + + Mandrill, 719 + + _Manidæ_, 204 + + _Manis_, 204 + + Manus, 48 + + Maral, 322 + + Markhoor, 354 + + Marmoset, 709 + + Marmot, 454 + Prairie, 456 + + Marsupialia, 128 + + Marten, 580 + + _Martes_, 580 + + _Mastacomys_, 476 + + _Mastodon_, 431 + + Megachiroptera, 650 + + _Megaderma_, 658 + + _Megaloglossus_, 655 + + _Megamys_, 488 + + _Megaptera_, 241 + + _Megatheriidæ_, 183 + + _Megatherium_, 185 + + Melanism, 9 + + _Meles_, 575 + + _Mellivora_, 576 + + _Melonycteris_, 654 + + _Melursus_, 560 + + _Menacodon_, 115 + + _Meniscoëssus_, 113 + + _Meniscomys_, 454 + + _Meniscotherium_, 439 + + _Menodus_, 413 + + _Mephitis_, 572 + + _Merychippus_, 380 + + _Merycochœrus_, 293 + + _Mesodectes_, 640 + + _Mesohippus_, 376 + + _Mesomys_, 483 + + _Mesonychidæ_, 609 + + _Mesonyx_, 609 + + _Mesopithecus_, 727 + + _Mesoplodon_, 254 + + _Mesotaria_, 606 + + _Mesotherium_, 440 + + Mesozoic mammals, 108 + + Metacarpus, 49 + + _Metamynodon_, 412 + + Metatheria, 128 + + _Metriotherium_, 294 + + _Miacidæ_, 539 + + _Miacis_, 539 + + _Microcavia_, 491 + + _Microcebus_, 690 + + _Microchœrus_, 696 + + _Microchiroptera_, 655 + + Microconodon, 113 + + _Microgale_, 638 + + _Microlestes_, 111 + + _Micromeryx_, 330 + + _Micronycteris_, 673 + + _Microsorex_, 624 + + _Microsyops_, 698 + + _Microtus_, 466 + + _Midas_, 710 + + Milk-teeth, 20 + + _Mimon_, 674 + + _Miniopterus_, 664 + + Mink, 586 + + _Miohippus_, 376 + + _Miosiren_, 223 + + _Mixodectes_, 699 + + Mole, 630 + Golden, 639 + Star-nosed, 630 + + Mole-Rat, 477 + + _Molossus_, 670 + + _Monachus_, 604 + + _Monatherium_, 606 + + Monkey, 699 + + Monodelphia, 173 + + _Monodon_, 260 + + _Monophylla_, 674 + + Monophyodont, 20 + + Moose, 326 + + _Morenia_, 484 + + _Mormops_, 672 + + _Moropus_, 413 + + _Morotherium_, 413 + + Morse, 597 + + _Moschinæ_, 314 + + _Moschus_, 314 + + Moufflon, 356 + + Mouse, 475 + + Mouth, 54 + + Mulita, 201 + + Multituberculata, 109 + + Mungoose, 535 + + Muntjac, 316 + + _Muridæ_, 461 + + _Mus_, 473 + + _Muscardinus_, 460 + + Musk Deer, 314 + Ox, 358 + Rat, 470, 626 + + Musquash, 470 + + _Mustela_, 579 + + _Mustelidæ_, 567 + + _Mycetes_, 711 + + _Mydaus_, 575 + + _Mylodon_, 189 + + _Myodes_, 467 + + _Myogale_, 628 + + _Myolagus_, 492 + + Myomorpha, 459 + + _Myopotamus_, 482 + + _Myoscalops_, 478 + + _Myosorex_, 625 + + _Myoxidæ_, 459 + + _Myoxus_, 459 + + _Myrmecobiinæ_, 140 + + _Myrmecobius_, 140 + + _Myrmecophaga_, 190 + + _Myrmecophagidæ_, 190 + + _Mysarachne_, 634 + + _Mystacina_, 671 + + Mystacoceti, 234 + + _Mystacops_, 671 + + _Mystromys_, 462 + + _Myxocebus_, 689 + + _Myxopoda_, 665 + + + Nails, 12 + + Nakong, 346 + + _Nandinia_, 534 + + _Nanotragus_, 339 + + Nares, 66 + + Narwhal, 261 + + _Nasalis_, 725 + + _Nasua_, 566 + + _Natalus_, 664 + + Nearctic region, 102 + + _Necrogymnurus_, 621 + + _Necrolemur_, 696 + + _Necromantis_, 679 + + _Nectogale_, 627 + + _Nectomys_, 464 + + _Nemorhædus_, 350 + + _Neobalæna_, 241 + + _Neofiber_, 472 + + _Neomeris_, 266 + + _Neoplagiaulax_, 113 + + _Neosorex_, 624 + + _Neotoma_, 464 + + _Neotragus_, 338 + + Neotropical region, 103 + + Nerves, 71 + + _Nesocerodon_, 491 + + _Nesocia_, 475 + + _Nesodon_, 439 + + _Nesomys_, 465 + + _Nesonycteris_, 655 + + _Nesotragus_, 339 + + _Neurotrichus_, 629 + + Nilghai, 345 + + _Nimravus_, 524 + + _Noctilio_, 668 + + Nostrils, 66 + + _Notharctus_, 698 + + _Nothropus_, 183 + + _Nothrotherium_, 184 + + _Notiosorex_, 624 + + _Notopteris_, 654 + + _Nototheriidæ_, 172 + + _Nototherium_, 171 + + _Nyctereutes_, 552 + + _Nycteridæ_, 658 + + _Nycteris_, 659 + + _Nycticebus_, 691 + + _Nycticejus_, 662 + + _Nyctilestes_, 665 + + _Nyctinomus_, 670 + + _Nyctipithecus_, 714 + + _Nyctitherium_, 665 + + _Nyctophilus_, 661 + + + Ocelot, 521 + + _Ochetodon_, 464 + + _Octodon_, 481 + + _Octodontidæ_, 480 + + _Odobænus_, 597 + + Odontoceti, 247 + + _Ogmorhinus_, 605 + + _Ommatophoca_, 605 + + _Onotragus_, 339 + + _Onychogale_, 166 + + _Onychomys_, 463 + + Opossum, 133 + + Orang, 731 + + _Orca_, 267 + + _Orcella_, 267 + + _Oreas_, 348 + + _Oreodon_, 293 + + _Oreopithecus_, 728 + + _Oreotragus_, 339 + + Oriental region, 100 + + Ornithodelphia, 117 + + _Ornithorhynchidæ_, 119 + + _Ornithorhynchus_, 119 + + _Orohippus_, 374 + + _Orotherium_, 374 + + _Orthaspidotherium_, 634 + + _Orthomys_, 484 + + _Orycteropodidæ_, 208 + + _Orycteropus_, 208 + + _Oryx_, 343 + + _Oryzomys_, 463 + + _Oryzorictes_, 638 + + _Otaria_, 593 + + _Otariidæ_, 593 + + _Otocyon_, 554 + + _Otomys_, 462 + + _Otonycteris_, 661 + + _Otopterus_, 673 + + Otter, 568 + Sea, 571 + + Ounce, 517 + + Ovaries, 75 + + _Ovibos_, 357 + + Oviduct, 75 + + _Ovis_, 354 + + Oxen, 360 + + _Oxhyæna_, 608 + + _Oxymycterus_, 464 + + + Paca, 489 + + _Pachyacanthus_, 224 + + Pachydermata, 87 + + _Pachynolophus_, 374 + + _Pachyuromys_, 462 + + _Paciculus_, 465 + + Palæarctic region, 97 + + _Palæocastor_, 458 + + _Palæocetus_, 245 + + _Palæoerinaceus_, 621 + + _Palæolemur_, 697 + + _Palæomanis_, 208 + + _Palæomeryx_, 330 + + _Palæonycteris_, 657 + + _Palæophoca_, 606 + + _Palæopontoporia_, 259 + + _Palæoprionodon_, 539 + + _Palæoreas_, 348 + + _Palæoryx_, 344 + + _Palæospalax_, 629 + + _Palæosyops_, 413 + + _Palæotapirus_, 373 + + _Palæotheriidæ_, 375 + + _Palæotherium_, 375 + + _Palæotragoceros_, 349 + + _Palauchenia_, 303 + + _Palhyæna_, 544 + + Palla, 341 + + Palm-Civet, 532 + + _Paloplotherium_, 375 + + _Palorchestes_, 170 + + Panda, 562 + + Pangolin, 205 + + _Panochthus_, 203 + + Panther, 514 + + _Pantholops_, 341 + + _Paradoxurus_, 532 + + _Paramys_, 457 + + _Parasorex_, 618 + + Peccary, 289 + + Pecora, 307 + + _Pectinator_, 481 + + _Pedetes_, 480 + + _Pediotragus_, 339 + + _Pelea_, 339 + + _Pellegrinia_, 484 + + Pelvis, 50 + + _Pelycodus_, 699 + + _Peragale_, 143 + + _Peralestes_, 115 + + _Peramelidæ_, 141 + + _Perameles_, 142 + + _Peratherium_, 135 + + _Periptychus_, 439 + + Perissodactyla, 368 + + _Perodicticus_, 693 + + _Perognathus_, 479 + + Pes, 52 + + _Petauroides_, 152 + + _Petaurus_, 153 + + _Petrodromus_, 618 + + _Petrogale_, 167 + + _Petromys_, 482 + + _Phacochœrus_, 288 + + _Phalanger_, 149 + + _Phalangeridæ_, 147 + + _Phalangerinæ_, 149 + + Phalanges, 49 + + _Phalangista_, 149 + + _Phascolarctinæ_, 155 + + _Phascolarctus_, 156 + + _Phascologale_, 139 + + _Phascolomyidæ_, 144 + + _Phascolomys_, 145 + + _Phascolonus_, 146 + + _Phascolotherium_, 114 + + _Phenacodus_, 439 + + _Phenacomys_, 466 + + Phlœomyinæ, 462 + + _Phlœomys_, 462 + + _Phloramys_, 484 + + _Phoca_, 601 + + _Phocæna_, 263 + + _Phocanella_, 606 + + _Phocidæ_, 600 + + _Phylloderma_, 674 + + _Phyllonycteris_, 674 + + Phyllophaga, 178 + + _Phyllorhina_, 657 + + _Phyllostoma_, 674 + + _Phyllostomatidæ_, 672 + + _Physeter_, 248 + + _Physeteridæ_, 247 + + _Physeterinæ_, 248 + + _Physeterula_, 251 + + _Physetodon_, 251 + + _Physodon_, 251 + + Pica, 492 + + Pichiciago, 196 + + Pig, 282 + + Pilosa, 179 + + Pinnipedia, 592 + + _Pithanotomys_, 484 + + _Pithechirus_, 477 + + _Pithecia_, 712 + + Placenta, 75 + + _Plagiaulacidæ_, 113 + + _Plagiaulax_, 111 + + _Plagiodon_, 483 + + _Platacanthomyinæ_, 461 + + _Platacanthomys_, 462 + + _Platanista_, 258 + + _Platanistidæ_, 257 + + _Platycercomys_, 480 + + _Platygonus_, 291 + + _Platyonyx_, 188 + + _Platyphoca_, 606 + + _Platypus_, 120 + + _Plecotus_, 660 + + _Plesiadapis_, 698 + + _Plesiarctomys_, 457 + + _Plesictis_, 590 + + _Plesiocetus_, 245 + + Plesiometacarpalia, 316 + + _Plesiosorex_, 634 + + _Plesispermophilus_, 457 + + _Pleuraspidotherium_, 634 + + _Pleurolichus_, 479 + + _Plexochœrus_, 491 + + _Pliauchenia_, 304 + + _Pliolagostomus_, 488 + + _Pliolophus_, 374 + + _Pliopithecus_, 731 + + _Poëbrotherium_, 304 + + _Pœcilogale_, 590 + + _Pœcilophoca_, 605 + + _Poëphagus_, 360 + + _Pogonodon_, 524 + + _Poiana_, 531 + + Polecat, 587 + + _Polymastodon_, 113 + + Polyprotodontia, 133 + + _Pontistes_, 259 + + _Pontoporia_, 259 + + Porcupine, 486 + Tree, 485 + + Porpoise, 263 + + _Potamarchus_, 488 + + _Potamochœrus_, 286 + + _Potamogale_, 635 + + _Potamogalidæ_, 634 + + _Potamophilus_, 534 + + _Potamotherium_, 570 + + _Potoroinæ_, 162 + + Potoroo, 163 + + _Potorous_, 163 + + Pouched-Rat, 478 + + _Praopus_, 201 + + Prehallux, 49 + + Prepollex, 49 + + Primates, 680 + + _Priodon_, 198 + + _Prionodon_, 530 + + _Priscodelphinus_, 259 + + _Proælurus_, 523 + + Proboscidea, 418 + + _Probubalus_, 361 + + _Procamelus_, 304 + + _Procapra_, 341 + + _Procavia_, 417 + + _Procoptodon_, 170 + + _Procyon_, 564 + + _Procyonidæ_, 562 + + _Prodelphinus_, 271 + + _Prodremotherium_, 307 + + _Proechidna_, 126 + + _Prohalicore_, 223 + + _Prohyæna_, 562 + + _Prolagostomus_, 488 + + _Promegatherium_, 189 + + _Promylodon_, 190 + + Prong-buck, 333 + + _Prophoca_, 606 + + _Propithecus_, 684 + + _Prorastomatidæ_, 224 + + _Prorastomus_, 224 + + _Protechinomys_, 484 + + _Proteleidæ_, 539 + + _Proteles_, 539 + + _Proterotheriidæ_, 414 + + _Proterotherium_, 414 + + _Protoadapis_, 698 + + _Protohippus_, 380 + + _Protolabis_, 304 + + _Protoreodon_, 293 + + Prototheria, 117 + + _Protoxodon_, 440 + + _Protragelaphus_, 349 + + _Protragoceros_, 349 + + _Proviverra_, 608 + + _Proviverridæ_, 608 + + _Prox_, 317 + + _Pseudælurus_, 523 + + _Pseudalopex_, 552 + + _Pseudochirus_, 151 + + _Pseudois_, 355 + + _Pseudorca_, 268 + + _Pseudorhinolophus_, 657 + + _Pseudosciurus_, 454 + + _Psittacotherium_, 442 + + _Pteralopex_, 654 + + _Pterodon_, 608 + + _Pteromys_, 453 + + _Pteropodidæ_, 650 + + _Pteropus_, 651 + + _Ptilocercus_, 618 + + _Ptilodus_, 113 + + _Pudua_, 330 + + Puma, 520 + + _Putorius_, 585 + + + Quagga, 384 + + + Rabbit, 494 + Bandicoot, 143 + + Raccoon, 565 + + _Rangifer_, 324 + + Rasse, 527 + + Rat, 474 + + Ratel, 576 + + Rat-Kangaroo, 163 + + Red Deer, 322 + + Rehbok, 339 + + Reitbok, 349 + + Reproductive organs, 74 + + Respiratory system, 63 + + _Rhabdosteus_, 259 + + _Rhachianectes_, 241 + + _Rhinoceros_, 402 + + _Rhinocerotidæ_, 402 + + _Rhinogale_, 537 + + _Rhinolophidæ_, 656 + + _Rhinolophus_, 656 + + _Rhinonycteris_, 658 + + _Rhinophylla_, 674 + + _Rhinopithecus_, 726 + + _Rhinopoma_, 669 + + _Rhipidomys_, 463 + + _Rhithrodon_, 464 + + _Rhithrosciurus_, 452 + + _Rhizomys_, 477 + + _Rhizoprion_, 257 + + _Rhogeëssa_, 661 + + _Rhynchocyon_, 618 + + _Rhynchonycteris_, 667 + + _Rhytina_, 221 + + _Rhytinidæ_, 221 + + Ribs, 44 + + River-Hog, 286 + + Rock-Wallaby, 167 + + Rodentia, 443 + + Roe, 327 + + Rorqual, 242 + + _Rosmarus_, 597 + + Ruminants, 307 + + _Rupicapra_, 349 + + _Rytiodus_, 223 + + + Sable, 584 + + _Saccomys_, 479 + + _Saccopteryx_, 667 + + _Saccostomus_, 477 + + Sacrum, 43 + + _Saiga_, 341 + + Saki, 712 + + Salivary glands, 55 + + Sambur, 320 + + _Samotherium_, 333 + + Sapajou, 717 + + _Sarcophilus_, 137 + + _Scaldicetus_, 251 + + Scales, 11 + + _Scalops_, 630 + + _Scapanus_, 630 + + _Scapteromys_, 464 + + _Scaptochirus_, 633 + + _Scaptonyx_, 630 + + _Scelidotherium_, 188 + + _Schizodelphis_, 259 + + _Schizodon_, 482 + + _Schizostoma_, 673 + + _Sciuravus_, 457 + + _Sciuridæ_, 450 + + _Sciurodon_, 454 + + _Sciuroides_, 454 + + Sciuromorpha, 448 + + _Sciuropterus_, 453 + + _Sciurus_, 450 + + _Scopophorus_, 339 + + _Scotophilus_, 662 + + _Scotozous_, 661 + + Sea-Leopard, 605 + + Sea-otter, 571 + + Seal, 600 + Eared, 594 + + _Selenacodon_, 113 + + _Semnopithecus_, 726 + + Sense organs, 69 + + Serow, 351 + + Sheep, 354 + + Shoulder-girdle, 46 + + Shrew, 622 + Tree, 617 + Water, 625 + + Siamang, 728 + + _Siamanga_, 728 + + Sight, 72 + + _Sigmodon_, 464 + + _Simia_, 731 + + _Simiidæ_, 728 + + _Simocyon_, 562 + + Simplicidentata, 448 + + _Siphneus_, 472 + + Sirenia, 212 + + _Sivatherium_, 322 + + Skeleton, 33 + + Skull, 34 + + Skunk, 572 + + Sloth, 180 + + Sloth, Ground, 184 + + Smell, 72 + + _Sminthopsis_, 139 + + _Sminthus_, 479 + + _Solenodon_, 636 + + _Solenodontidæ_, 635 + + _Sorex_, 622 + + _Soricidæ_, 621 + + _Soriculus_, 624 + + _Sotalia_, 272 + + Souslik, 456 + + _Spalacidæ_, 477 + + _Spalacopus_, 482 + + _Spalacotherium_, 115 + + _Spalax_, 477 + + _Spaniotherium_, 294 + + _Spermophilus_, 456 + + Sperm Whale, 249 + + Spider Monkey, 715 + + _Spilogale_, 574 + + Spiny Anteater, 124 + + Spleen, 65 + + _Squalodon_, 257 + + _Squalodontidæ_, 257 + + Squamata, 179 + + Squirrel, 451 + + _Stegodon_, 427 + + _Steneofiber_, 458 + + _Steno_, 271 + + _Stenoderma_, 676 + + _Stenoplesictis_, 539 + + _Stenops_, 691 + + _Stenorhynchus_, 605 + + _Stereognathus_, 110 + + Sternum, 44 + + _Sthenurus_, 170 + + Stoat, 590 + + Stomach, 57 + + _Strepsiceros_, 347 + + _Sturnira_, 676 + + _Stylacodon_, 114 + + _Stylinodon_, 442 + + _Styloceros_, 317 + + _Stylodon_, 114 + + _Stypolophus_, 608 + + Subungulata, 414 + + _Suidæ_, 281 + + Suina, 278 + + _Suricata_, 538 + + _Sus_, 281 + + _Syllophodus_, 484 + + _Symborodon_, 413 + + _Synaptomys_, 467 + + _Synetheres_, 485 + + _Synotus_, 661 + + _Systemodon_, 374 + + + Takin, 351 + + _Talpa_, 630 + + _Talpidæ_, 628 + + _Tamandua_, 192 + + _Tamias_, 452 + + _Taphozous_, 667 + + Tapir, 371 + + _Tapiridæ_, 370 + + _Tapirulus_, 294 + + _Tapirus_, 370 + + Tardigrada, 178 + + _Tarsiidæ_, 694 + + _Tarsipedinæ_, 148 + + _Tarsipes_, 148 + + _Tarsius_, 694 + + Taste, 72 + + Tatouay, 198 + + _Tatusia_, 200 + + _Tatusiinæ_, 200 + + _Taxidea_, 576 + + Tayra, 579 + + Teetee, 713 + + Teeth, 13 + + Tegument, 7 + + Teledu, 575 + + Telemetacarpalia, 323 + + _Temnocyon_, 555 + + Tenrec, 637 + + _Terphone_, 338 + + Tertiary mammals, 115 + + _Tetraceros_, 338 + + _Tetraconodon_, 292 + + _Tetracus_, 634 + + _Tetrastylus_, 488 + + _Theridomyidæ_, 484 + + _Theridomys_, 484 + + _Theropithecus_, 722 + + Thigh, 51 + + _Thomomys_, 478 + + _Thoracophorus_, 203 + + Thylacine, 137 + + _Thylacinus_, 136 + + _Thylacoleo_, 157 + + Thymus gland, 66 + + Thyroid body, 66 + + _Thyroptera_, 665 + + Tiger, 511 + + Tillodontia, 441 + + _Tillotherium_, 441 + + _Tinoceras_, 437 + + _Titanomys_, 492 + + _Titanotheriidæ_, 413 + + _Titanotherium_, 413 + + _Tolypeutes_, 199 + + _Tomitherium_, 698 + + _Toxodon_, 439 + + Toxodontia, 439 + + Touch, 72 + + Trachea, 67 + + _Trachyops_, 674 + + _Trachytherium_, 224 + + _Tragelaphus_, 346 + + _Tragoceros_, 349 + + _Tragops_, 341 + + _Tragulidæ_, 305 + + Tragulina, 305 + + _Tragulus_, 305 + + _Trechomys_, 484 + + _Triacanthodon_, 113 + + _Triænops_, 658 + + _Trichechidæ_, 596 + + _Trichechus_, 597 + + _Trichosurus_, 150 + + _Trichys_, 487 + + _Triclis_, 162 + + _Triconodon_, 113 + + _Trilodon_, 484 + + Trituberculism, 30 + + _Tritylodon_, 111 + + _Trochictis_, 570 + + _Troglodytes_, 736 + + _Trogontherium_, 458 + + _Trygenycteris_, 655 + + Tubulidentata, 179 + + _Tupaia_, 617 + + _Tupaiidæ_, 617 + + _Tursiops_, 271 + + Tylopoda, 295 + + _Tylostoma_, 674 + + _Typhlomys_, 477 + + _Typotherium_, 440 + + + _Uacaria_, 712 + + Uakari, 712 + + _Uintatheriidæ_, 437 + + _Uintatherium_, 436 + + Umbilical vesicle, 77 + + Unau, 183 + + Ungulata, 273 + + Urinary organs, 69 + + _Urocyon_, 553 + + _Uromys_, 476 + + _Uropsilus_, 629 + + _Urotrichus_, 629 + + _Ursidæ_, 557 + + _Ursus_, 557 + + Urus, 367 + + Uses of mammals, 4 + + Uterus, 75 + + + Vampyre, 676 + + _Vampyrus_, 673 + + Vertebræ, 39 + + _Vesperimus_, 463 + + _Vespertiliavus_, 666 + + _Vespertilio_, 663 + + _Vespertilionidæ_, 660 + + _Vesperugo_, 661 + + Vicugna, 300 + + Viscacha, 488 + + _Vishnutherium_, 332 + + _Viverra_, 526 + + _Viverricula_, 527 + + _Viverridæ_, 525 + + Vole, 465 + + _Vulpes_, 552 + + Vulpine Phalanger, 150 + + + Wallaby, 169 + + Walrus, 597 + + Wapiti, 322 + + Wart-Hog, 288 + + Weasel, 589 + + Whale, 225 + + White Whale, 262 + + Wolf, 548 + + Wolverene, 591 + + Wombat, 145 + + + _Xantharpyia_, 652 + + _Xenurus_, 198 + + _Xeromys_, 461 + + _Xerus_, 452 + + _Xiphodon_, 294 + + + Yak, 364 + + Yapock, 134 + + Yolk-sac, 77 + + + _Zapus_, 480 + + Zebra, 385 + + _Zeuglodon_, 246 + + _Zeuglodontidæ_, 246 + + _Ziphiinæ_, 251 + + _Ziphius_, 254 + + Zoological regions, 96 + + +THE END + +_Printed by R. & R. CLARK, Edinburgh_ + + + +*** END OF THE PROJECT GUTENBERG EBOOK 75947 *** |