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-Project Gutenberg's The History of Creation, Vol. II (of 2), by Ernst Haeckel
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-almost no restrictions whatsoever.  You may copy it, give it away or
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-
-Title: The History of Creation, Vol. II (of 2)
-       Or the Development of the Earth and its Inhabitants by the
-       Action of Natural Causes
-
-Author: Ernst Haeckel
-
-Translator: E. Ray Lankester
-
-Release Date: August 14, 2012 [EBook #40473]
-
-Language: English
-
-Character set encoding: UTF-8
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-*** START OF THIS PROJECT GUTENBERG EBOOK HISTORY OF CREATION, VOL II ***
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+*** START OF THE PROJECT GUTENBERG EBOOK 40473 ***
 
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   | Transcriber’s note:                                              |
@@ -14694,361 +14656,4 @@ _D. APPLETON & CO., Publishers, 1, 3, & 5 Bond Street, N. Y._
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 Ernst Haeckel
 
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+*** END OF THE PROJECT GUTENBERG EBOOK 40473 ***
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-Project Gutenberg's The History of Creation, Vol. II (of 2), by Ernst Haeckel
-
-This eBook is for the use of anyone anywhere at no cost and with
-almost no restrictions whatsoever.  You may copy it, give it away or
-re-use it under the terms of the Project Gutenberg License included
-with this eBook or online at www.gutenberg.org
-
-
-Title: The History of Creation, Vol. II (of 2)
-       Or the Development of the Earth and its Inhabitants by the
-       Action of Natural Causes
-
-Author: Ernst Haeckel
-
-Translator: E. Ray Lankester
-
-Release Date: August 14, 2012 [EBook #40473]
-
-Language: English
-
-Character set encoding: ISO-8859-1
-
-*** START OF THIS PROJECT GUTENBERG EBOOK HISTORY OF CREATION, VOL II ***
-
-
-
-
-Produced by Adrian Mastronardi, Turgut Dincer, Jason Palmer
-and the Online Distributed Proofreading Team at
-http://www.pgdp.net (This file was produced from images
-generously made available by The Internet Archive)
-
-
-
-
-
-
-
-
-
-  +------------------------------------------------------------------+
-  | Transcriber's note:                                              |
-  |                                                                  |
-  | This book was published in two volumes, of which this is the     |
-  | second. The first volume was released as Project Gutenberg ebook |
-  | #40472, available at http://www.gutenberg.org/ebooks/40472       |
-  |                                                                  |
-  | Numbers enclosed in square brackets, e.g. [1], relate to         |
-  | footnotes, which have been placed at the end of the text.        |
-  | Numbers enclosed in parentheses, e.g. (1), relate to works       |
-  | referred to in the text and listed at the end of this volume.    |
-  |                                                                  |
-  | In the text versions of these two volumes, words in _italics_    |
-  | are enclosed in underscores, +bold+ words are enclosed in plus   |
-  | signs, and words in =Gothic script= are enclosed in equal signs. |
-  | Curly brackets are used to represent subscripts, e.g. k{1}.      |
-  +------------------------------------------------------------------+
-
-
-
-
-  THE HISTORY OF CREATION.
-
-
-
-
-[Illustration: Hypothetical Sketch of the Monophyletic Origin of Man.]
-
-
-
-
-  THE
-  HISTORY OF CREATION:
-
-  _OR THE DEVELOPMENT OF THE EARTH AND ITS
-  INHABITANTS BY THE ACTION OF NATURAL CAUSES._
-
-  A POPULAR EXPOSITION OF
-  THE DOCTRINE OF EVOLUTION IN GENERAL, AND OF THAT OF
-  DARWIN, GOETHE, AND LAMARCK IN PARTICULAR.
-
-  FROM THE GERMAN OF
-  ERNST HAECKEL,
-  PROFESSOR IN THE UNIVERSITY OF JENA.
-
-  THE TRANSLATION REVISED BY
-  PROFESSOR E. RAY LANKESTER, M.A., F.R.S.,
-  FELLOW OF EXETER COLLEGE, OXFORD.
-
-  _IN TWO VOLUMES._
-  VOL. II.
-
-  NEW YORK:
-  D. APPLETON AND COMPANY,
-  1, 3, AND 5 BOND STREET.
-  1880.
-
-
-
-
-                        A sense sublime
-  Of something far more deeply interfused,
-  Whose dwelling is the light of setting suns,
-  And the round ocean, and the living air,
-  And the blue sky, and in the mind of man;
-  A motion and a spirit that impels
-  All thinking things, all objects of all thought,
-  And rolls through all things.
-
-  In all things, in all natures, in the stars
-  Of azure heaven, the unenduring clouds,
-  In flower and tree, in every pebbly stone
-  That paves the brooks, the stationary rocks,
-  The moving waters and the invisible air.
-
-                                   WORDSWORTH.
-
-
-
-
-CONTENTS OF VOL. II.
-
-
-  CHAPTER XV.
-                                                                    PAGE
-  PERIODS OF CREATION AND RECORDS OF CREATION.
-
-  Reform of Systems by the Theory of Descent.--The Natural System
-  as a Pedigree.--Palæontological Records of the
-  Pedigree.--Petrifactions as Records of Creation.--Deposits of the
-  Neptunic Strata and the Enclosure of Organic Remains.--Division
-  of the Organic History of the Earth into Five Main Periods:
-  Period of the Tangle Forests, Fern Forests, Pine Forests,
-  Foliaceous Forests, and of Cultivation.--The Series of Neptunic
-  Strata.--Immeasurable Duration of the Periods which have elapsed
-  during their Formation.--Deposits of Strata only during the
-  Sinking, not during the Elevation of the Ground.--Other Gaps in
-  the Records of Creation.--Metamorphic Condition of the most
-  Ancient Neptunic Strata.--Small Extent of Palæontological
-  Experience.--Small proportion of Organisms and of Parts of
-  Organisms Capable of Petrifying.--Rarity of many Petrified
-  Species.--Want of Fossilised Intermediate Forms.--Records of the
-  Creation in Ontogeny and in Comparative Anatomy                      1
-
-
-  CHAPTER XVI.
-
-  PEDIGREE AND HISTORY OF THE KINGDOM OF THE PROTISTA.
-
-  Special Mode of Carrying out the Theory of Descent in the
-  Natural System of Organisms.--Construction of Pedigrees.--Descent
-  of all Many-celled from Single-celled Organisms.--Descent of
-  Cells from Monera.--Meaning of Organic Tribes, or Phyla.--Number
-  of the Tribes in the Animal and Vegetable Kingdoms.--The
-  Monophyletic Hypothesis of Descent, or the Hypothesis of one
-  Common Progenitor, and the Polyphyletic Hypothesis of Descent,
-  or the Hypothesis of many Progenitors.--The Kingdom of Protista,
-  or Primæval Beings.--Eight Classes of the Protista Kingdom:
-  Monera, Amoebæ, or Protoplastæ; Whip-swimmers, or Flagellata;
-  Ciliated-balls, Cili Catallacta; Labyrinth-streamers, or
-  Labyrinthuleæ; Flint-cells, or Diatomeæ; Mucous-moulds, or
-  Myxomycetes; Root-footers (Rhizopoda).--Remarks on the General
-  Natural History of the Protista: Their Vital Phenomena,
-  Chemical Composition, and Formation (Individuality and
-  Fundamental Form).--Phylogeny of the Prostista Kingdom              36
-
-
-  CHAPTER XVII.
-
-  PEDIGREE AND HISTORY OF THE VEGETABLE KINGDOM.
-
-  The Natural System of the Vegetable Kingdom.--Division of the
-  Vegetable Kingdom into Six Branches and Eighteen Classes.--The
-  Flowerless Plants (Cryptogamia).--Sub-kingdom of the Thallus
-  Plants.--The Tangles, or Algæ (Primary Algæ, Green Algæ, Brown
-  Algæ, Red Algæ).--The Thread-plants, or Inophytes (Lichens and
-  Fungi).--Sub-kingdom of the Prothallus Plants.--The Mosses, or
-  Muscinæ (Water-mosses, Liverworts, Leaf-mosses,
-  Bog-mosses).--The Ferns, or Filicinæ (Leaf-ferns, Bamboo-ferns,
-  Water-ferns, Scale-ferns).--Sub kingdom of Flowering Plants
-  (Phanerogamia).--The Gymnosperms, or Plants with Naked Seeds
-  (Palm-ferns = Cycadeæ; Pines = Coniferæ).--The Angiosperms, or
-  Plants with Enclosed Seeds.--Monocotylæ.--Dicotylæ.--Cup-blossoms
-  (Apetalæ).--Star-blossoms (Diapetalæ).--Bell-blossoms
-  (Gamopetalæ)                                                        77
-
-
-  CHAPTER XVIII.
-
-  PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-  I. ANIMAL-PLANTS AND WORMS.
-
-  The Natural System of the Animal Kingdom.--Linnæus' and Lamarck's
-  Systems.--The Four Types of Bär and Cuvier.--Their Increase to
-  Seven Types.--Genealogical Importance of the Seven Types as
-  Independent Tribes of the Animal Kingdom.--Derivation of
-  Zoophytes and Worms from Primæval Animals.--Monophyletic and
-  Polyphyletic Hypothesis of the Descent of the Animal
-  Kingdom.--Common Origin of the Four Higher Animal Tribes out of
-  the Worm Tribe.--Division of the Seven Animal Tribes into
-  Sixteen Main Classes, and Thirty-eight Classes.--Primæval
-  Animals (Monera, Amoebæ, Synamoebæ), Gregarines, Infusoria,
-  Planæades, and Gastræades (Planula and Gastrula).--Tribe of
-  Zoophytes.--Spongiæ (Mucous Sponges, Fibrous Sponges, Calcareous
-  Sponges).--Sea Nettles, or Acalephæ (Corals, Hood-jellies,
-  Comb-jellies).--Tribe of Worms                                     117
-
-
-  CHAPTER XIX.
-
-  PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-  II. MOLLUSCA, STAR-FISHES, AND ARTICULATED ANIMALS.
-
-  Tribe of Molluscs.--Four Classes of Molluscs: Lamp-shells
-  (Spirobranchia); Mussels (Lamellibranchia); Snails (Cochlides);
-  Cuttle-fish (Cephalopoda).--Tribe of Star-fishes, or
-  Echinoderma.--Their Derivation from Ringed Worms (Mailed Worms,
-  or Phracthelminthes).--The Alternation of Generation in the
-  Echinoderma.--Four Classes of Star-fish: Sea-stars (Asteridea);
-  Sea-lilies (Crinoidea); Sea-urchins (Echinidea); Sea-cucumbers
-  (Holothuridea).--Tribe of Articulated Animals, or
-  Arthropoda.--Four Classes of Articulated Animals: Branchiata, or
-  Crustacea, breathing through gills; Jointed Crabs; Mailed
-  Crabs; Articulata Tracheata, breathing through Air
-  Tubes.--Spiders (Long Spiders, Round
-  Spiders).--Myriopods.--Insects.--Chewing and Sucking
-  Insects.--Pedigree and History of the Eight Orders of Insects      154
-
-
-  CHAPTER XX.
-
-  PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-  III. VERTEBRATE ANIMALS.
-
-  The Records of the Creation of Vertebrate Animals (Comparative
-  Anatomy, Embryology, and Palæontology).--The Natural System of
-  Vertebrate Animals.--The Four Classes of Vertebrate Animals,
-  according to Linnæus and Lamarck.--Their Increase to Nine
-  Classes.--Main Class of the Tube-hearted, or Skull-less Animals
-  (the Lancelet).--Blood Relationship between the Skull-less Fish
-  and the Tunicates.--Agreement in the Embryological Development
-  of Amphioxus and Ascidiæ.--Origin of the Vertebrate Tribe out of
-  the Worm Tribe.--Main Class of Single-nostriled, or
-  Round-mouthed Animals (Hag and Lampreys).--Main Class of
-  Anamnionate Animals, devoid of Amnion.--Fishes (Primæval Fish,
-  Cartilaginous Fish, Osseous Fish).--Mud-fish, or Dipneusta.--Sea
-  Dragons, or Halisauria.--Frogs and Salamanders, or Amphibia
-  (Mailed Amphibia, Naked Amphibia).--Main Class of Amnionate
-  Animals, or Amniota.--Reptiles (Primary Reptiles, Lizards,
-  Serpents, Crocodiles, Tortoises, Flying Reptiles, Dragons,
-  Beaked Reptiles).--Birds (Feather-tailed, Fan-tailed,
-  Bush-tailed)                                                       192
-
-
-  CHAPTER XXI.
-
-  PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-  IV. MAMMALS.
-
-  The System of Mammals according to Linnæus and
-  Blainville.--Three Sub-classes of Mammals (Ornithodelphia,
-  Didelphia, Monodelphia).--Ornithodelphia, or Monotrema.--Beaked
-  Animals (Ornithostoma).--Didelphia, or Marsupials.--Herbivorous
-  and Carnivorous Marsupials.--Monodelphia, or Placentalia
-  (Placental Animals).--Meaning of the Placenta.--Tuft
-  Placentalia.--Girdle Placentalia.--Disc
-  Placentalia.--Non-deciduates, or Indeciduata.--Hoofed
-  Animals.--Single and Double-hoofed Animals.--Whales.--Toothless
-  Animals.--Deciduates, or Animals with
-  Decidua.--Semi-apes.--Gnawing Animals.--Pseudo-hoofed
-  Animals.--Insectivora.--Beasts of Prey.--Bats.--Apes               231
-
-
-  CHAPTER XXII.
-
-  ORIGIN AND PEDIGREE OF MAN.
-
-  The Application of the Theory of Descent to Man.--Its Immense
-  Importance and Logical Necessity.--Man's Position in the Natural
-  System of Animals, among Disco-placental Animals.--Incorrect
-  Separation of the Bimana and Quadrumana.--Correct Separation of
-  Semi-apes from Apes.--Man's Position in the Order of
-  Apes.--Narrow-nosed Apes (of the Old World) and Flat-nosed Apes
-  (of America).--Difference of the two Groups.--Origin of Man from
-  Narrow-nosed Apes.--Human Apes, or Anthropoides.--African
-  Human-apes (Gorilla and Chimpanzee).--Asiatic Human-apes (Orang
-  and Gibbon).--Comparison between the different Human Apes and
-  the different Races of Men.--Survey of the Series of the
-  Progenitors of Man.--Invertebrate Progenitors (Prochordata) and
-  Vertebrate Progenitors                                             263
-
-
-  CHAPTER XXIII.
-
-  MIGRATION AND DISTRIBUTION OF MANKIND. HUMAN SPECIES AND HUMAN
-  RACES.
-
-  Age of the Human Race.--Causes of its Origin.--The Origin of
-  Human Language.--Monophyletic or Single, Polyphyletic or
-  Multiple Origin of the Human Race.--Derivation of Man from many
-  Pairs.--Classification of the Human Races.--System of Twelve
-  Species of Men.--Woolly-Haired Men, or Ulotrichis.--Bushy-Haired
-  (Papuans, Hottentots).--Fleecy-haired (Caffres,
-  Negroes).--Straight-haired Men, or Lissotrichi.--Stiff-haired
-  (Australians, Malays, Mongols, Arctic, and American
-  Tribes).--Curly-haired (Dravidas, Nubians, Midlanders).--Number
-  of Population.--Primæval Home of Man (South Asia, or
-  Lemuria).--Nature of Primæval Men.--Number of Primæval Languages
-  (Monoglottists and Polyglottists).--Divergence and Migration of
-  the Human Race.--Geographical Distribution of the Human Species    296
-
-
-  CHAPTER XXIV.
-
-  OBJECTIONS AGAINST, AND PROOFS OF THE TRUTH OF, THE THEORY OF
-  DESCENT.
-
-  Objections to the Doctrine of Filiation.--Objections of Faith
-  and Reason.--Immeasurable Length of the Geological
-  Periods.--Transition Forms between Kindred Species.--Dependence
-  of Stability of Form on Inheritance, and of the Variability of
-  Form on Adaptation.--Origin of very Complicated Arrangement of
-  Organisation.--Gradual Development of Instincts and Mental
-  Activities.--Origin of à priori Knowledge from Knowledge a
-  posteriori.--The Knowledge requisite for the Correct
-  Understanding of the Doctrine of Filiation.--Necessary
-  Interaction between Empiricism and Philosophy.--Proofs of the
-  Theory of Descent.--Inner Causal-Connection between all the
-  Biological Series of Phenomena.--The Direct Proof of the Theory
-  of Selection.--Relation of the Theory of Descent to
-  Anthropology.--Proofs of the Animal Origin of Man.--The Pithecoid
-  Theory as an Inseparable Part of the Theory of
-  Descent.--Induction and Deduction.--Gradual Development of the
-  Human Mind.--Body and Mind.--Human Soul and Animal Soul.--A Glance
-  at the Future                                                      334
-
-
-  LIST OF WORKS REFERRED TO IN THE TEXT                              371
-
-  APPENDIX (Explanation of the Plates)                               379
-
-  INDEX                                                              402
-
-
-
-
-LIST OF ILLUSTRATIONS.
-
-
-PLATES.
-
-    XV.--Hypothetical Sketch of the Monophyletic Origin
-          of Man                                          _Frontispiece_
-
-    IV.--Hand of Nine different Mammals                _To face page_ 34
-
-     V.--Single-Stemmed, or Monophyletic, Pedigree of the
-          Vegetable Kingdom                                    "     112
-
-    VI.--Historical Growth of the Six Great Stems of Animals   "     122
-
-   VII.--Animal Plants, or Zoophytes                           "     140
-
-  VIII.--Star Fishes--First Generation            _Between pp._ 170, 171
-
-    IX.--Star Fishes--Second Generation                 "        "    "
-
-     X.--Nauplius-Youth-Form of Six Crab Fish           "       174, 175
-
-    XI.--Adult-Form of the same Six Crab Fish           "        "    "
-
-   XII.--Ascidia and Amphioxus                          "       201, 202
-
-  XIII.--Ascidia and Amphioxus                          "        "    "
-
-   XIV.--Single, or Monophyletic, Pedigree of Back-boned
-         Animals                                      _To face page_ 222
-
-
-  FIGURES.
-
-   8.--Protamoeba Primitiva                                           52
-
-   9.--Bathybius Hæckelii                                             53
-
-  10.--Amoeba Sphærococcus                                            54
-
-  11.--Euglena Striata                                                57
-
-  12.--Magosphæra Planula                                             58
-
-  13.--Labyrinthula Macrocystis                                       59
-
-  14.--Navicula Hippocampus                                           60
-
-  15.--Physarum Albipes                                               61
-
-  16.--Cyrtidosphæra Echinoides                                       66
-
-  17.--Caulerpa Denticulata                                           87
-
-  18.--Euastrum Rota                                                  88
-
-  19.--Fucus Vesiculosus (egg of)                                     90
-
-
-
-
-THE HISTORY OF CREATION.
-
-
-
-
-CHAPTER XV.
-
-PERIODS OF CREATION AND RECORDS OF CREATION.
-
-
-  Reform of Systems by the Theory of Descent.--The Natural System
-  as a Pedigree.--Palæontological Records of the
-  Pedigree.--Petrifactions as Records of Creation.--Deposits of the
-  Neptunic Strata and the Enclosure of Organic Remains.--Division
-  of the Organic History of the Earth into Five Main Periods:
-  Period of the Tangle Forests, Fern Forests, Pine Forests,
-  Foliaceous Forests, and of Cultivation.--The Series of Neptunic
-  Strata.--Immeasurable Duration of the Periods which have elapsed
-  during their Formation.--Deposits of Strata only during the
-  Sinking, not during the Elevation of the Ground.--Other Gaps in
-  the Records of Creation.--Metamorphic Condition of the most
-  Ancient Neptunic Strata.--Small Extent of Palæontological
-  Experience.--Small proportion of Organisms and of Parts of
-  Organisms Capable of Petrifying.--Rarity of many Petrified
-  Species.--Want of Fossilised Intermediate Forms.--Records of the
-  Creation in Ontogeny and in Comparative Anatomy.
-
-
-The revolutionary influence which the Theory of Descent must exercise
-upon all sciences, will in all probability affect no branch of science,
-excepting Anthropology, so much as the descriptive portion of natural
-history, that which is known as systematic Zoology and Botany. Most
-naturalists who have hitherto occupied themselves with arranging the
-different systems of animals and plants, have collected, named, and
-arranged the different species of these natural bodies with much the
-same interest as antiquarians and ethnographers collect the weapons and
-utensils of different nations. Many have not even risen above the degree
-of intelligence with which people usually collect, label, and arrange
-crests, stamps, and similar curiosities. In the same manner as some
-collectors find their pleasure in the similarity of forms, the beauty or
-rarity of the crests or stamps, and admire in them the inventive art of
-man, so many naturalists take a delight in the manifold forms of animals
-and plants, and marvel at the rich imagination of the Creator, at His
-unwearied creative activity, and at His curious fancy for forming, by
-the side of so many beautiful and useful organisms, also a number of
-ugly and useless ones.
-
-This childlike treatment of systematic Zoology and Botany is completely
-annihilated by the Theory of Descent. In the place of the superficial
-and playful interest with which most naturalists have hitherto regarded
-organic structures, we now have the much higher interest of the
-intelligent understanding which detects in the _related forms_ of
-organisms their true _blood relationships_. The _Natural System of
-animals and plants_, which was formerly valued either only as a registry
-of names, to facilitate the survey of the different forms, or as a table
-of contents for the short expression of their degrees of similarity,
-receives from the Theory of Descent the incomparably higher value of a
-true _pedigree of organisms_. This pedigree is to disclose to us the
-genealogical connection of the smaller and larger groups. It has to show
-us in what way the different classes, orders, families, genera, and
-species of the animal and vegetable kingdoms correspond with the
-different branches, twigs, and groups of twigs of the pedigree. Every
-wider and higher category or stage of the system (for example a class,
-or an order) comprises a number of larger and stronger branches of the
-pedigree; every narrower and lower category (for example a genus, or a
-species) only a smaller and thinner group of twigs. It is only when we
-thus view the natural system as a pedigree that we perceive its true
-value. (Gen. Morph. ii. Plate XVII. p. 397.)
-
-Since we hold fast this genealogical conception of the Organic System,
-to which alone undoubtedly the future of classificatory Zoology and
-Botany belongs, we should now turn our attention to one of the most
-essential, but also one of the most difficult, tasks of the
-"non-miraculous history of creation," namely, to the actual construction
-of the Organic Pedigree. Let us see how far we are already able to point
-out all the different organic forms as the divergent descendants of a
-single or of some few common original forms. But how can we construct
-the actual pedigree of the animal and vegetable group of forms from our
-knowledge of them, at present so scanty and fragmentary? The answer to
-this question lies in what we have already remarked of the parallelism
-of the three series of development--in the important causal relation
-which connects the palæontological development of all organic tribes
-with the embryological development of individuals, and with the
-systematic development of groups.
-
-In order to accomplish our task we shall first have to direct our
-attention to _palæontology_, or _the science of petrifactions_. For if
-the Theory of Descent is really true, if the petrified remains of
-formerly living animals and plants really proceed from the extinct
-primæval ancestors and progenitors of the present organisms, then,
-without anything else, the knowledge and comparison of petrifactions
-ought to disclose to us the pedigree of organisms. However simple and
-clear this may seem in theory, the task becomes extremely hard and
-complicated when it is actually taken in hand. Its practical solution
-would be very difficult even if the petrifactions were to any extent
-completely preserved. But this is by no means the case. The obvious
-records of creation which lie buried in petrifactions are imperfect
-beyond all measure. Hence it is necessary critically to examine these
-records, and to determine the value which petrifactions possess for the
-history of the development of organic tribes. As I have previously
-discussed the general importance of petrifactions as the records of
-creation, when we were considering Cuvier's merits in the science of
-fossils, we may now at once examine the conditions and circumstances
-under which the remains of organic bodies became petrified and preserved
-in a more or less recognizable form.
-
-As a rule we find petrifactions or fossils enclosed only in those stones
-which have been deposited in layers as mud by water, and which are on
-that account called neptunic, stratified, or sedimentary rocks. The
-deposition of such strata could of course only commence after the
-condensation of watery vapour into liquid water had taken place in the
-course of the earth's history. After that period, which we considered in
-our last chapter, not only did life begin on the earth, but also an
-uninterrupted and exceedingly important transformation of the rigid
-inorganic crust of the earth. The water began that extremely important
-mechanical action by which the surface of the earth is perpetually,
-though slowly, transformed. I may surely presume that it is generally
-known what an extremely important influence, in this respect, is even
-yet exercised by water at every moment. As it falls down as rain,
-trickling through the upper strata of the earth's crust, and flowing
-down from heights into hollows, it chemically dissolves different
-mineral parts of the ground, and mechanically washes away the loose
-particles. In flowing down from mountains water carries their debris
-into the plains, or deposits it as mud in stagnant lakes. Thus it
-continually works at lowering mountains and filling up valleys. In like
-manner the breakers of the sea work uninterruptedly at the destruction
-of the coasts and at filling up the bottom of the sea with the debris
-they wash down. The action of water alone, if it were not counteracted
-by other circumstances, would in time level the whole earth. There can
-be no doubt that the mountain masses--which are annually carried down as
-mud into the sea, and deposited on its floor--are so great that in the
-course of a longer or shorter period, say a few millions of years, the
-surface of the earth would be completely levelled and become enclosed by
-a continuous sheet of water. That this does not happen is owing to the
-perpetual volcanic action of the fiery-fluid centre of the earth. The
-surging of the melted nucleus against the firm crust necessitates
-continual alternations of elevation and depression on the different
-parts of the earth's surface. These elevations and depressions for the
-most part take place very slowly; but, as they continue for thousands of
-years, by the combined effect of small, interrupted movements, they
-produce results no less grand than does the counteracting and levelling
-action of water.
-
-Since the elevations and depressions of the different parts of the
-earth alternate with one another in the course of millions of years,
-first this and then that part of the earth's surface is above or below
-the level of the sea. I have already given examples of this in the
-preceding chapter (vol. i. p. 361). Hence, in all probability, there is
-no part of the outer crust of the earth which has not been repeatedly
-above and also below the level of the sea. This repeated change explains
-the variety and the different composition of the numerous neptunic
-strata of rocks, which in most places have been deposited one above
-another in considerable thickness. In the different periods of the
-earth's history during which these deposits took place there lived
-various and different populations of animals and plants. When their dead
-bodies sank to the bottom of the waters, the forms of the bodies
-impressed themselves upon the soft mud, and imperishable parts, such as
-hard bones, teeth, shells, etc., became enclosed in it uninjured. These
-were preserved in the mud, which condensed them into neptunic rock, and
-as petrifactions they now serve to characterise the respective strata.
-By a careful comparison of the different strata lying one above another,
-and the petrifactions preserved in them, it has become possible to
-decide the relative age of the strata and groups of strata, and to
-establish, by direct observation, the principal eras of phylogeny, that
-is to say, the stages in history of the development of animal and
-vegetable tribes.
-
-The different strata of neptunic rocks deposited one above another,
-which are composed in very various ways of limestone, clay, and sand,
-geologists have grouped together into an ideal System or Series, which
-corresponds with the whole course of the organic history of the earth,
-or with that portion of the earth's history during which organic life
-existed. Just as so-called "universal history" falls into larger and
-smaller periods, which are characterized by the conditions of
-development of the most important nations at the respective epochs, and
-are separated from one another by great events, so we also divide the
-infinitely longer organic history of the earth into a series of greater
-and less periods. Each of these periods is distinguished by a
-characteristic flora and fauna, and by the specially strong development
-of certain vegetable or animal groups, and each is separated from the
-preceding and succeeding period by a striking change in the character of
-its animal and vegetable inhabitants.
-
-In relation to the following survey of the historical course of
-development which the large animal and vegetable tribes have passed
-through, it will be desirable to say a few words first as to the
-systematic classification of the neptunic groups of strata, and the
-larger and smaller periods corresponding to them. As will be seen
-directly, we are able to divide the whole of the sedimentary rocks lying
-one above another into five main groups or periods, each period into
-several subordinate groups of strata or _systems_, and each system of
-strata again into still smaller groups or _formations_; finally, each
-formation can again be divided into stages or sub-formations, and each
-of these again into still smaller layers or beds. Each of the five great
-rock-groups was deposited during a great division of the earth's
-history, during a long _era_ or _epoch_; each system during a shorter
-_period_; each formation during a still shorter _period_. In thus
-reducing the periods of the organic history of the earth, and the
-neptunic strata containing petrifactions deposited during those periods
-into a connected system, we proceed exactly like the historian who
-divides the history of nations into the three main divisions of
-Antiquity, the Middle Ages, and Modern Times, and each of those sections
-again into subordinate periods and epochs. But the historian by this
-sharp systematic division, and by fixing the boundary of the periods by
-particular dates, only seeks to facilitate his survey, and in no way
-means to deny the uninterrupted connection of events and the development
-of nations. Exactly the same qualification applies to our systematic
-division, specification, or classification of the organic history of the
-earth. Here, too, a continuous thread runs through the series of events
-unbroken. We must therefore distinctly protest against the idea that by
-sharply bounding the larger and smaller groups of strata, and the
-periods corresponding with them, we in any way wish to adopt Cuvier's
-doctrine of terrestrial revolutions, and of repeated new creations of
-organic populations. That this erroneous doctrine has long since been
-completely refuted by Lyell, I have already mentioned. (Compare vol. i.
-p. 127.)
-
-The five great main divisions of the organic history of the earth, or
-the palæontological history of development, we call the primordial,
-primary, secondary, tertiary, and quaternary epochs. Each is distinctly
-characterized by the predominating development of certain animal and
-vegetable groups in it, and we might accordingly symbolically designate
-the five epochs, on the one hand by the names of the groups of the
-vegetable kingdom, and on the other hand by those of the different
-classes of vertebrate animals. In this case the _first_, or primordial
-epoch, would be the era of the Tangles (Algæ) and skull-less
-Vertebrates; the _second_, or primary epoch, that of the Ferns and
-Fishes; the _third_, or secondary epoch, that of Pine Forests and
-Reptiles; the _fourth_, or tertiary epoch, that of Foliaceous Forests
-and of Mammals; finally, the _fifth_, or quaternary epoch, the era of
-Man, and his Civilization. The divisions or _periods_ which we
-distinguish in each of the five _long eras_ (p. 14) are determined by
-the different _systems_ of strata into which each of the five great
-_rock-groups_ is divided (p. 15). We shall now take a cursory glance at
-the series of these systems, and at the same time at the populations of
-the five great epochs.
-
-The first and longest division of the organic history of the earth is
-formed by the _primordial epoch_, or _the era of the Tangle Forests_. It
-comprises the immense period from the first spontaneous generation, from
-the origin of the first terrestrial organism, to the end of the Silurian
-system of deposits. During this immeasurable space of time, which in all
-probability was much longer than all the other four epochs taken
-together, the three most extensive of all the neptunic systems of strata
-were deposited, namely, the _Laurentian_, upon that the _Cambrian_, and
-upon that the _Silurian_ system. The approximate thickness or size of
-these three systems together amounts to 70,000 feet. Of these about
-30,000 belong to the Laurentian, 18,000 to the Cambrian, and 22,000 to
-the Silurian system. The average thickness of all the four other rock
-groups, the primary, secondary, tertiary, and quaternary, taken
-together, may amount at most to 60,000 feet; and from this fact alone,
-apart from many other reasons, it is evident that the duration of the
-primordial period was probably much longer than the duration of all the
-subsequent periods down to the present day. Many thousands of millions
-of years were required to deposit such masses of strata. Unfortunately,
-by far the largest portion of the primordial group of strata is in the
-metamorphic state (which we shall directly explain), and consequently
-the petrifactions contained in them--the most ancient and most important
-of all--have, to a great extent, been destroyed and become
-unrecognisable. Only in one portion of the Cambrian strata have
-petrifactions been preserved in a recognizable condition and in large
-quantities. The most ancient of all distinctly preserved petrifactions
-has been found in the lowest Laurentian strata (in the Ottawa
-formation), which I shall afterwards have to speak of as the "Canadian
-Life's-dawn" (Eozoon canadense).
-
-Although only by far the smaller portion of the primordial or
-archilithic petrifactions are preserved to us in a recognizable
-condition, still they possess the value of inestimable documents of the
-most ancient and obscure times of the organic history of the earth. What
-seems to be shown by them, in the first place, is that during the whole
-of this immense period there existed only inhabitants of the waters. As
-yet, at any rate, among all archilithic petrifactions, not a single one
-has been found which can with certainty be regarded as an organism which
-has lived on land. All the vegetable remains we possess of the
-primordial period belong to the lowest of all groups of plants, to the
-class of Tangles or Algæ, living in water. In the warm primæval sea,
-these constituted the forests of the period, of the richness of which in
-forms and density we may form an approximate idea from their present
-descendants, the tangle forests of the Atlantic Sargasso sea. The
-colossal tangle forests of the archilithic period supplied the place of
-the forest vegetation of the mainland, which was then utterly wanting.
-All the animals, also, whose remains have been found in archilithic
-strata, like the plants, lived in water. Only crustacea are met with
-among the animals with articulated feet, as yet no spiders and no
-insects. Of vertebrate animals, only a very few remains of fishes are
-known as having been found in the most recent of all primordial strata,
-in the upper Silurian. But the headless vertebrate animals, which we
-call _skull-less_, or _Acrania_, and out of which fishes must have been
-developed, we suppose to have lived in great numbers during the
-primordial epoch. Hence we may call it after the _Acrania_ as well as
-after the _Tangles_.
-
-The _primary epoch_, or _the era of Fern Forests_, the second main
-division of the organic history of the earth, which is also called the
-palæolithic or palæozoic period, lasted from the end of the Silurian
-formation of strata to the end of the Permian formation. This epoch was
-also of very long duration, and again falls into three shorter periods,
-during which three great systems of strata were deposited, namely,
-first, the _Devonian_ system, or the old red sandstone; upon that, the
-_Carboniferous_, or coal system; and upon this, the _Permian_ system.
-The average thickness of these three systems taken together may amount
-to about 42,000 feet, from which we may infer the immense length of time
-requisite for their formation.
-
-The Devonian and Permian formations are especially rich in remains of
-fishes, of primæval fish as well as enamelled fish (Ganoids), but the
-bony fish (Teleostei) are absent from the strata of the primary epoch.
-In coal are found the most ancient remains of animals living on land,
-both of articulated animals (spiders and insects) as well as of
-vertebrate animals (amphibious animals, like newts and frogs). In the
-Permian system there occur, in addition to the amphibious animals, the
-more highly-developed reptiles, and, indeed, forms nearly related to our
-lizards (Proterosaurus, etc.). But, nevertheless, we may call the
-primary epoch that of _Fishes_, because these few amphibious animals and
-reptiles are insignificant in comparison with the immense mass of
-palæozoic fishes. Just as Fishes predominate over the other vertebrate
-animals, so _Ferns_, or Filices, predominate among the plants of this
-epoch, and, in fact, real ferns and tree ferns (leafed ferns, or
-Phylopteridæ), as well as bamboo ferns (Calamophytæ) and scaled ferns
-(Lepidophytæ). These ferns, which grew on land, formed the chief part of
-the dense palæolithic island forests, the fossil remains of which are
-preserved to us in the enormously large strata of coal of the
-Carboniferous system, and in the smaller strata of coal of the Devonian
-and Permian systems. We are thus justified in calling the primary epoch
-either the era of _Ferns_ or that of _Fishes_.
-
-The third great division of the palæontological history of development
-is formed by the _secondary epoch_, or the _era of Pine Forests_, which
-is also called the mesolithic or mesozoic epoch. It extends from the end
-of the Permian system to the end of the Chalk formation, and is again
-divided into three great periods. The stratified systems deposited
-during this period are, first and lowest, the _Triassic_ system, in the
-middle the _Jura_ system, and at the top the _Cretaceous_ system. The
-average thickness of these three systems taken together is much less
-than that of the primary group, and amounts as a whole only to about
-15,000 feet. The secondary epoch can accordingly in all probability not
-have been half so long as the primary epoch.
-
-Just as Fishes prevailed in the primary epoch, _Reptiles_ predominated
-in the secondary epoch over all other vertebrate animals. It is true
-that during this period the first birds and mammals originated; at that
-time, also, there existed important amphibious animals, especially the
-gigantic Labyrinthodonts, in the sea the wonderful sea-dragons, or
-Halisaurii, swam about, and the first fish with bones were associated
-with the many primæval fishes (Sharks) and enamelled fish (Ganoids) of
-the earlier times; but the very variously developed kinds of reptiles
-formed the predominating and characteristic class of vertebrate animals
-of the secondary epoch. Besides those reptiles which were very nearly
-related to the present living lizards, crocodiles, and turtles, there
-were, during the mesolithic period, swarms of grotesquely shaped
-dragons. The remarkable flying lizards, or Pterosaurii, and the colossal
-land-dragons, or Dinosaurii, of the secondary epoch, are peculiar, as
-they occur neither in the preceding nor in the succeeding epochs. The
-secondary epoch may be called the era of _Reptiles_; but on the other
-hand, it may also be called the era of _Pine Forests_, or more
-accurately, of the _Gymnosperms_, that is, the epoch of _plants having
-naked seeds_. For this group of plants, especially as represented by the
-two important classes--the pines, or _Coniferæ_, and the palm-ferns, or
-_Cycadeæ_--during the secondary epoch constituted a predominant part of
-the forests. But towards the end of the epoch (in the Chalk period) the
-plants of the pine tribe gave place to the leaf-bearing forests which
-then developed for the first time.
-
-
-SURVEY
-
-_Of the Palæontological Periods, or of the Greater Divisions of the
-Organic History of the Earth._
-
-
-I. _First Epoch_: ARCHILITHIC ERA. _Primordial Epoch._
-
-(Era of Skull-less Animals and Forests of Tangles.)
-
-  1. Older Primordial Period     or    Laurentian Period.
-  2. Middle Primordial Period    "     Cambrian Period.
-  3. Later Primordial Period     "     Silurian Period.
-
-
-II. _Second Epoch_: PALÆOLITHIC ERA. _Primary Epoch._
-
-(Era of Fish and Fern Forests.)
-
-  4. Older Primary Period    or    Devonian Period.
-  5. Mid Primary Period      "     Coal Period.
-  6. Later Primary Period    "     Permian Period.
-
-
-III. _Third Epoch_: MESOLITHIC ERA. _Secondary Epoch._
-
-(Era of Reptiles and Pine Forests.)
-
-  7. Older Secondary Period     or    Trias Period.
-  8. Middle Secondary Period    "     Jura Period.
-  9. Later Secondary Period     "     Chalk Period.
-
-
-IV. _Fourth Epoch_: CÆNOLITHIC ERA. _Tertiary Epoch._
-
-(Era of Mammals and Leaf Forests.)
-
-  10. Older Tertiary Period     or    Eocene Period.
-  11. Newer Tertiary Period     "     Miocene Period.
-  12. Recent Tertiary Period    "     Pliocene Period.
-
-
-V. _Fifth Epoch_: ANTHROPOLITHIC ERA. _Quaternary Epoch._
-
-(Era of Man and Cultivated Forests.)
-
-  13. Older Quaternary Period     or    Ice or Glacial Period.
-  14. Newer Quaternary Period     "     Post Glacial Period.
-  15. Recent Quaternary Period    "     Period of Culture.
-
-(The Period of Culture is the Historical Period, or the Period of
-Tradition.)
-
-SURVEY
-
-_Of the Palæontological Formations, or those Strata of the Earth's Crust
-containing Petrifactions._
-
-
-  --------------------+-------------------+----------------------+--------------
-     _Rock-Groups._   |    _Systems._     |    _Formations._     | _Synonyms of
-                      |                   |                      |  Formations._
-  --------------------+-------------------+----------------------+-------------
-  V. _Quaternary      {                                          |
-     Group_,          { XIV. Recent       { 36. _Present_        | Upper alluvial
-     or               { (Alluvium)        { 35. _Recent_         | Lower alluvial
-     Anthropolithic   {                                          |
-     (Anthropozoic)   { XIII. Pleistocene { 34. _Post glacial_   | Upper diluvial
-     groups of        { (Diluvium)        { 33. _Glacial_        | Lower diluvial
-     strata           {                                          |
-
-
-  IV. _Tertiary       { XII. Pliocene     { 32. _Arvernian_      | Upper pliocene
-      Group_,         { (Late tertiary)   { 31. _Sub-Appenine_   | Lower pliocene
-      or              {                                          |
-      Cænolithic      { XI. Miocene       { 30. _Falunian_       | Upper miocene
-      (Cænozoic)      { (New tertiary)    { 29. _Limburgian_     | Lower miocene
-      groups of       {                                          |
-      strata          {                   { 28. _Gypsum_         | Upper eocene
-                      {   X. Eocene       { 27. _Nummulitic_     | Mid eocene
-                      { (Old tertiary)    { 26. _London clay_    | Lower eocene
-
-
-                      {                   { 25. _White chalk_    | Upper cretaceous
-                      { IX. Cretaceous    { 24. _Green sand_     | Mid cretaceous
-                      {                   { 23. _Neocomian_      | Lower cretaceous
-  III. _Secondary     {                   { 22. _Wealden_        | The Kentish Weald
-       Group_,        {
-       or             {                   { 21. _Portlandian_    | Upper oolite
-       Mesolithic     {  VIII. Jura       { 20. _Oxfordian_      | Mid oolite
-       (Mesozoic)     {                   { 19. _Bath_           | Lower oolite
-       groups of      {                   { 18. _Lias_           | Lias formation
-       strata         {
-                      {                   { 17. _Keuper_         | Upper trias
-                      {  VII. Trias       { 16. _Muschel-kalk_   | Mid trias
-                      {                   { 15. _Bunter sand_    | Lower trias
-
-
-                      { VI. Permian       { 14. _Zechstein_      | Upper Permian
-  II. _Primary        {                   { 13.                  | Lower Permian
-       Group_,        {                   { 12. _Carboniferous   |
-       or             { V. Carbonic              sandstone_      | Upper carbonic
-       Palæolithic    {     (coal)        { 11. _Carboniferous   |
-      (Palæozoic)     {                   {       limestone_     | Lower carbonic
-       groups of      { IV. Devonian      { 10. _Pilton_         | Upper Devonian
-       strata         {(Old red sandstone){  9. _Ilfracombe_     | Mid Devonian
-                                          {  8. _Linton_         | Lower Devonian
-
-
-  I. _Primordial     {                    {  7. _Ludlow_         | Upper Silurian
-     Group_,         { III. Silurian      {  6. _Llandovery_     | Mid Silurian
-     or              {                    {  5. _Llandeilo_      | Lower Silurian
-     Archilithic     {
-     (Archizoic)     { II. Cambrian       {  4. _Potsdam_        | Upper Cambrian
-     groups of       {                    {  3. _Longmynd_       | Lower Cambrian
-     strata          {
-                     { I. Laurentian      {  2. _Labrador_       | Upper Laurentian
-                     {                    {  1. _Ottawa_         | Lower Laurentian
-
-
-The fourth main division of the organic history of the earth, the
-_tertiary epoch_, or _era of Leafed Forests_, is much shorter and less
-peculiar than the three first epochs. This epoch, which is also called
-the cænolithic or cænozoic epoch, extended from the end of the
-cretaceous system to the end of the pliocene system. The strata
-deposited during it amount only to a thickness of about 3000 feet, and
-consequently are much inferior to the three first great groups. The
-three systems also into which the tertiary period is subdivided are very
-difficult to distinguish from one another. The oldest of them is called
-_eocene_, or old tertiary; the newer _miocene_, or mid tertiary; and the
-last is the _pliocene_, or later tertiary system.
-
-The whole population of the tertiary epoch approaches much nearer, on
-the whole as well as in detail, to that of the present time than is the
-case in the preceding epochs. From this time the class of _Mammals_
-greatly predominates over all other vertebrate animals. In like manner,
-in the vegetable kingdom, the group--so rich in forms--of the
-_Angiosperms_, or _plants with covered seeds_, predominates, and its
-_leafy forests_ constitute the characteristic feature of the tertiary
-epoch. The group of the Angiosperms consists of the two classes of
-single-seed-lobed plants, or _Monocotyledons_, and the double-seed-lobed
-plants, or _Dicotyledons_. The Angiosperms of both classes had, it is
-true, made their appearance in the Cretaceous period, and mammals had
-already occurred in the Jurassic period, and even in the Triassic
-period; but both groups, the mammals and the plants with enclosed seeds,
-did not attain their peculiar development and supremacy until the
-tertiary epoch, so that it may justly be called after them.
-
-The fifth and last main division of the organic history of the earth is
-the _quaternary epoch, or era of Civilization_, which in comparison with
-the length of the four other epochs almost vanishes into nothing, though
-with a comical conceit we usually call its record the "history of the
-world." As the period is characterized by the development of _Man_ and
-his _Culture_, which has influenced the organic world more powerfully
-and with greater transforming effect than have all previous conditions,
-it may also be called the era of Man, the anthropolithic or anthropozoic
-period. It might also be called the era of Cultivated Forests, or
-Gardens, because even at the lowest stage of human civilization man's
-influence is already perceptible in the utilization of forests and their
-products, and therefore also in the physiognomy of the landscape. The
-commencement of this era, which extends down to the present time, is
-geologically bounded by the end of the pliocene stratification.
-
-The neptunic strata which have been deposited during the comparatively
-short quaternary epoch are very different in different parts of the
-earth, but they are mostly of very slight thickness. They are reduced to
-two "systems," the older of which is designated the _diluvial_, or
-_pleistocene_, and the later the _alluvial_, or _recent_. The diluvial
-system is again divided into two "formations," the older _glacial_ and
-the more recent _post glacial_ formations. For during the older diluvial
-period there occurred that extremely remarkable decrease of the
-temperature of the earth which led to an extensive glaciation of the
-temperate zones. The great importance which this "ice" or "glacial
-period" has exercised on the geographical and topographical distribution
-of organisms has already been explained in the preceding chapter (vol.
-i. p. 365). But the _post glacial period_, or the more recent diluvial
-period, during which the temperature again increased and the ice
-retreated towards the poles, was also highly important in regard to the
-present state of chorological relations.
-
-The biological characteristic of the quaternary epoch lies essentially
-in the development and dispersion of the human organism and his culture.
-Man has acted with a greater transforming, destructive, and modifying
-influence upon the animal and vegetable population of the earth than any
-other organism. For this reason, and not because we assign to man a
-privileged exceptional position in nature in other matters, we may with
-full justice designate the development of man and his civilization as
-the beginning of a special and last main division of the organic history
-of the earth. It is probable indeed that the corporeal development of
-primæval man out of man-like apes took place as far back as the earlier
-pliocene period, perhaps even in the miocene tertiary period. But the
-actual development of _human speech_, which we look upon as the most
-powerful agency in the development of the peculiar characteristics of
-man and his dominion over other organisms, probably belongs to that
-period which on geological grounds is distinguished from the preceding
-pliocene period as the pleistocene or diluvial. In fact the time which
-has elapsed from the development of human speech down to the present
-day, though it may comprise many thousands and perhaps hundreds of
-thousands of years, almost vanishes into nothing as compared with the
-immeasurable length of the periods which have passed from the beginning
-of organic life on the earth down to the origin of the human race.
-
-The tabular view given on page 15 shows the succession of the
-palæontological rock-groups, systems, and formations, that is, the
-larger and smaller neptunic groups of strata, which contain
-petrifactions, from the uppermost, or Alluvial, down to the lowest, or
-Laurentian, deposits. The table on page 14 presents the historical
-division of the corresponding eras of the larger and smaller
-palæontological periods, and in a reversed succession, from the most
-ancient Laurentian up to the most recent Quaternary period.
-
-Many attempts have been made to make an approximate calculation of the
-number of thousands of years constituting these periods. The thickness
-of the strata has been compared, which, according to experience, is
-deposited during a century, and which amounts only to some few lines or
-inches, with the whole thickness of the stratified masses of rock, the
-succession of which we have just surveyed. This thickness, on the whole,
-may on an average amount to about 130,000 feet; of these 70,000 belong
-to the primordial, or archilithic; 42,000 to the primary, or
-palæolithic; 15,000 to the secondary, or mesolithic; and finally only
-3,000 to the tertiary, or cænolithic group. The very small and scarcely
-appreciable thickness of the quaternary, or anthropolithic deposit
-cannot here come into consideration at all. On an average, it may at
-most be computed as from 500 to 700 feet. But it is self evident that
-all these measurements have only an average and approximate value, and
-are meant to give only a rough survey of the _relative_ proportion of
-the systems of strata and of the spaces of time corresponding with them.
-
-Now, if we divide the whole period of the organic history of the
-earth--that is, from the beginning of life on the earth down to the
-present day--into a hundred equal parts, and if then, corresponding to
-the thickness of the systems of strata, we calculate the relative
-duration of the time of the five main divisions or periods according to
-percentages, we obtain the following result:--
-
-
-    I. Archilithic, or primordial period       53.6
-   II. Palæolithic, or primary period          32.1
-  III. Mesolithic, or secondary period         11.5
-   IV. Cænolithic, or tertiary period           2.3
-    V. Anthropolithic, or quaternary period     0.5
-                                              -----
-                                      Total   100.0
-
-
-According to this, the length of the archilithic period, during which no
-land-living animals or plants as yet existed, amounts to more than one
-half, more than 53 per cent.; on the other hand the length of the
-anthropolithic era, during which man has existed, amounts to scarcely
-one-half per cent. of the whole length of the organic history of the
-earth. It is, however, quite impossible to calculate the length of these
-periods, even approximately, by years.
-
-The thickness of the strata of mud at present deposited during a
-century, and which has been used as a basis for this calculation, is of
-course quite different in different parts of the earth under the
-different conditions in which these deposits take place. It is very
-slight at the bottom of the deep sea, in the beds of broad rivers with a
-short course, and in inland seas which receive very scanty supplies of
-water. It is comparatively great on the sea-shores exposed to strong
-breakers, at the estuaries of large rivers with long courses, and in
-inland seas with copious supplies of water. At the mouth of the
-Mississippi, which carries with it a considerable amount of mud, in the
-course of 100,000 years about 600 feet would be deposited. At the bottom
-of the open sea, far away from the coasts, during this long period only
-some few feet of mud would be deposited. Even on the sea-shores where a
-comparatively large quantity of mud is deposited the thickness of the
-strata formed during the course of a century may after all amount to no
-more than a few inches or lines when condensed into solid stone. In any
-case, however, all calculations based upon these comparisons are very
-unsafe, and we cannot even approximately conceive the enormous length of
-the periods which were requisite for the formation of the systems of
-neptunic strata. Here we can apply only relative, not absolute,
-measurements of time.
-
-Moreover, we should entirely err were we to consider the size of these
-systems of strata alone as the measure of the actual space of time which
-has elapsed during the earth's history. For the elevations and
-depressions of the earth's crust have perpetually alternated with one
-another, and the mineralogical and palæontological difference--which is
-perceived between each two succeeding systems of strata, and between
-each two of their formations at any particular spot--corresponds in all
-probability with a considerable intermediate space of many thousands of
-years, during which that particular part of the earth's crust was raised
-above the water. It was only after the lapse of this intermediate
-period, when a new depression again laid the part in question under
-water, that there occurred a new deposit of earth. As, in the mean time,
-the inorganic and organic conditions on this part had undergone a
-considerable transformation, the newly-formed layer of mud was
-necessarily composed of different earthy constituents and enclosed
-different petrifactions.
-
-  IV. Tertiary Group of            |
-  Strata, 3,000 feet.              |    Eocene, Miocene, Pliocene.
-  ---------------------------------+------------------------------
-                                   |    IX. Chalk System.
-  III. Mesolithic Group of Strata. |
-                                   |
-  Deposits of the                  |    VIII. Jura System.
-  Secondary Epoch, about           |
-  15,000 feet.                     |
-                                   |   VII. Trias System.
-  ---------------------------------+------------------------------
-                                   |
-                                   |    VI. Permian System.
-  II. Palæolithic Group of Strata. |
-                                   |
-  Deposits of the                  |     V. Coal System.
-  Primary Epoch, about             |
-  42,000 feet.                     |   IV. Devonian System.
-  ---------------------------------+------------------------------
-                                   |
-                                   |   III. Silurian System, about
-                                   |           22,000 feet.
-  I. Archilithic Group of Strata.  |
-                                   |
-  Deposits of the                  |   II. Cambrian System, about
-  Primordial Epoch, about          |           18,000 feet.
-  70,000 feet.                     |
-                                   |   I. Laurentian System, about
-                                   |           30,000 feet.
-
-
-The striking differences which so frequently occur between the
-petrifactions of two strata, lying one above another, are to be
-explained in a simple and easy manner by the supposition that the same
-part of the earth's surface has been exposed to _repeated depressions
-and elevations_. Such alternating elevations and depressions take place
-even now extensively, and are ascribed to the heaving of the fiery fluid
-nucleus against the rigid crust. Thus, for example, the coast of Sweden
-and a portion of the west coast of South America are constantly though
-slowly rising, while the coast of Holland and a portion of the east
-coast of South America are gradually sinking. The rising as well as the
-sinking takes place very slowly, and in the course of a century
-sometimes only amounts to some few lines, sometimes to a few inches, or
-at most a few feet. But if this action continues uninterruptedly
-throughout hundreds of thousands of years it is capable of forming the
-highest mountains.
-
-It is evident that elevations and depressions, such as now can be
-measured in these places, have uninterruptedly alternated one with
-another in different places during the whole course of the organic
-history of the earth. This may be inferred with certainty from the
-geographical distribution of organisms. (Compare vol. i. p. 350.) But to
-form a judgment of our palæontological records of creation it is
-extremely important to show that permanent strata can only be deposited
-during a slow sinking of the ground under water, but not during its
-continued rising. When the ground slowly sinks more and more below the
-level of the sea, the deposited layers of mud get into continually
-deeper and quieter water, where they can become condensed into stone
-undisturbed. But when, on the other hand, the ground slowly rises, the
-newly-deposited layers of mud, which enclose the remains of plants and
-animals, again immediately come within the reach of the play of the
-waves, and are soon worn away by the force of the breakers, together
-with the organic remains which they on close. For this simple but very
-important reason, therefore, abundant layers, in which organic remains
-are preserved, can only be deposited during a continuous sinking of the
-ground. When any two different formations or strata, lying one above the
-other, correspond with two different periods of depression, we must
-assume a long period of rising between them, of which period we know
-nothing, because no fossil remains of the then living animals and plants
-could be preserved. It is evident, however, that those _periods of
-elevation_, which have passed without leaving any trace behind them,
-deserve a no less careful consideration than the greater or less
-alternating _periods of depression_, of whose organic population we can
-form an approximate idea from the strata containing petrifactions.
-Probably the former were not of shorter duration than the latter.
-
-From this alone it is apparent how imperfect our records must
-necessarily be, and all the more so since it can be theoretically proved
-that the variety of animal and vegetable life must have increased
-greatly during those very periods of elevation. For as new tracts of
-land are raised above the water, new islands are formed. Every new
-island, however, is a new centre of creation, because the animals and
-plants accidentally cast ashore there, find in the new territory, in
-the struggle for life, abundant opportunity of developing themselves
-peculiarly, and of forming new species. The formation of new species has
-evidently taken place pre-eminently during these intermediate periods,
-of which, unfortunately, no petrifactions could be preserved, whereas,
-on the contrary, during the slow sinking of the ground there was more
-chance of numerous species dying out, and of a retrogression into fewer
-specific forms. The intermediate forms between the old and the
-newly-forming species must also have lived during the periods of
-elevation, and consequently could likewise leave no fossil remains.
-
-In addition to the great and deplorable gaps in the palæontological
-records of creation--which are caused by the periods of elevation--there
-are, unfortunately, many other circumstances which immensely diminish
-their value. I must mention here especially the _metamorphic state of
-the most ancient formations_, of those strata which contain the remains
-of the most ancient flora and fauna, the original forms of all
-subsequent organisms, and which, therefore, would be of especial
-interest. It is just these rocks--and, indeed, the greater part of the
-primordial, or archilithic strata, almost the whole of the Laurentian,
-and a large part of the Cambrian systems--which no longer contain any
-recognizable remains, and for the simple reason that these strata have
-been subsequently changed or metamorphosed by the influence of the fiery
-fluid interior of the earth. These deepest neptunic strata of the crust
-have been completely changed from their original condition by the heat
-of the glowing nucleus of the earth, and have assumed a crystalline
-state. In this process, however, the form of the organic remains
-enclosed in them has been entirely destroyed. It has been preserved only
-here and there by a happy chance, as in the case of the most ancient
-petrifactions known, the _Eozoon canadense_, from the lowest Laurentian
-strata. However, from the layers of crystalline charcoal (graphite) and
-crystalline limestone (marble), which are found deposited in the
-metamorphic rocks, we may with certainty conclude that petrified animal
-and vegetable remains existed in them in earlier times.
-
-Our record of creation is also extremely imperfect from the circumstance
-that only a small portion of the earth's surface has been accurately
-investigated by geologists, namely, England, Germany, and France. But we
-know very little of the other parts of Europe, of Russia, Spain, Italy,
-and Turkey. In the whole of Europe, only some few parts of the earth's
-crust have been laid open, by far the largest portion of it is unknown
-to us. The same applies to North America and to the East Indies. There
-some few tracts have been investigated; but of the larger portion of
-Asia, the most extensive of all continents, we know almost nothing; of
-Africa nothing, excepting the Cape of Good Hope and the shores of the
-Mediterranean; of Australia almost nothing; and of South America but
-very little. It is clear, therefore, that only quite a small portion,
-perhaps scarcely the thousandth part of the whole surface of the earth,
-has been palæontologically investigated. We may therefore reasonably
-hope, when more extensive geological investigations are made, which are
-greatly assisted by the constructions of railroads and mines, to find a
-great number of other important petrifactions. A hint that this will be
-the case is given by the remarkable petrifactions found in those parts
-of Africa and Asia which have been minutely investigated,--the Cape
-districts and the Himalaya mountains. A series of entirely new and very
-peculiar animal forms have become known to us from the rocks of these
-localities. But we must bear in mind that the vast bottom of the
-existing oceans is at the present time quite inaccessible to
-palæontological investigations, and that the greater part of the
-petrifactions which have lain there from primæval times will either
-never be known to us, or at best only after the course of many thousands
-of years, when the present bottom of the ocean shall have become
-accessible by gradual elevation. If we call to mind the fact that
-three-fifths of the whole surface of the earth consists of water, and
-only two-fifths of land, it becomes plain that on this account the
-palæontological record must always present an immense gap.
-
-But, in addition to these, there exists another series of difficulties
-in the way of palæontology which arises from the nature of the organisms
-themselves. In the first place, as a rule only the hard and solid parts
-of organisms can fall to the bottom of the sea or of fresh waters, and
-be there enclosed in the mud and petrified. Hence it is only the bones
-and teeth of vertebrate animals, the calcareous shells of molluscs, the
-chitinous skeletons of articulated animals, the calcareous skeletons of
-star-fishes and corals, and the woody and solid parts of plants, that
-are capable of being petrified. But soft and delicate parts, which
-constitute by far the greater portion of the bodies of most organisms,
-are very rarely deposited in the mud under circumstances favourable to
-their becoming petrified, or distinctly impressing their external form
-upon the hardening mud. Now, it must be borne in mind that large classes
-of organisms, as for example the Medusæ, the naked molluscs without
-shells, a large portion of the articulated animals, almost all worms,
-and even the lowest vertebrate animals, possess no firm and hard parts
-capable of being petrified. In like manner the most important parts of
-plants, such as the flowers, are for the most part so soft and tender
-that they cannot be preserved in a recognizable form. We therefore
-cannot expect to find any petrified remains of these important
-organisms. Moreover, all organisms at an early stage of life are so soft
-and tender that they are quite incapable of being petrified.
-Consequently all the petrifactions found in the neptunic stratifications
-of the earth's crust comprise altogether but a very few forms, and of
-these for the most part only isolated fragments.
-
-We must next bear in mind that the dead bodies of the inhabitants of the
-sea are much more likely to be preserved and petrified in the deposits
-of mud than those of the inhabitants of fresh water and of the land.
-Organisms living on land can, as a rule, become petrified only when
-their corpses fall accidentally into the water and are buried at the
-bottom in the hardening layers of mud. But this event depends upon very
-many conditions. We cannot therefore be astonished that by far the
-majority of petrifactions belong to organisms which have lived in the
-sea, and that of the inhabitants of the land proportionately only very
-few are preserved in a fossil state. How many contingencies come into
-play here we may infer from the single fact that of many fossil mammals,
-in fact of all the mammals of the secondary, or mesozoic epoch, nothing
-is known except the lower jawbone. This bone is in the first place
-comparatively solid, and in the second place very easily separates
-itself from the dead body, which floats on the water. Whilst the body is
-driven away and dissolved by the water, the lower jawbone falls down to
-the bottom of the water and is there enclosed in the mud. This explains
-the remarkable fact that in a stratum of limestone of the Jurassic
-system near Oxford, in the slates of Stonesfield, as yet only the lower
-jawbones of numerous pouched animals (Marsupials) have been found. They
-are the most ancient mammals known, and of the whole of the rest of
-their bodies not a single bone exists. The opponents of the theory of
-development, according to their usual logic, would from this fact be
-obliged to draw the conclusion that the lower jawbone was the only bone
-in the body of those animals.
-
-Footprints are very instructive when we attempt to estimate the many
-accidents which so arbitrarily influence our knowledge of fossils; they
-are found in great numbers in different extensive layers of sandstone;
-for example, in the red sandstone of Connecticut, in North America.
-These footprints were evidently made by vertebrate animals, probably by
-reptiles, of whose bodies not the slightest trace has been preserved.[1]
-The impressions which their feet have left on the mud alone betray the
-former existence of these otherwise unknown animals.
-
-The accidents which, besides these, determine the limits of our
-palæontological knowledge, may be inferred from the fact that we know of
-only one or two specimens of very many important petrifactions. It is
-not ten years since we became acquainted with the imperfect impression
-of a bird in the Jurassic or Oolitic system, the knowledge of which
-has been of the very greatest importance for the phylogeny of the whole
-class of birds. All birds previously known presented a very uniformly
-organized group, and showed no striking transitional forms to other
-vertebrate classes, not even to the nearly related reptiles. But that
-fossil bird from the Jura possessed not an ordinary bird's tail, but a
-lizard's tail, and thus confirmed what had been conjectured upon other
-grounds, namely, the derivation of birds from lizards. This single
-fossil has thus essentially extended not only our knowledge of the age
-of the class of birds, but also of their blood relationship to reptiles.
-In like manner our knowledge of other animal groups has been often
-essentially modified by the accidental discovery of a single fossil. The
-palæontological records must necessarily be exceedingly imperfect,
-because we know of so very few examples, or only mere fragments of very
-many important fossils.
-
-Another and very sensible gap in these records is caused by the
-circumstance that the _intermediate forms_ which connect the different
-species have, as a rule, not been preserved, and for the simple reason
-that (according to the principle of divergence of character) they were
-less favoured in the struggle for life than the most divergent
-varieties, which had developed out of one and the same original form.
-The intermediate links have, on the whole, always died out _rapidly_,
-and have but rarely been preserved as fossils. On the other hand, the
-most divergent forms were able to maintain themselves in life for a
-longer period as independent species, to propagate more numerously, and
-consequently to be more readily petrified. But this does not exclude the
-fact that in _some_ cases the connecting intermediate forms of the
-species have been preserved so perfectly petrified, that even now they
-cause the greatest perplexity and occasion endless disputes among
-systematic palæontologists about the arbitrary limits of species.
-
-An excellent example of this is furnished by the celebrated and very
-variable fresh-water snail from the Stuben Valley, near Steinheim, in
-Würtemburg, which has been described sometimes as _Paludina_, sometimes
-as _Valvata_, and sometimes as _Planorbis multiformis_. The snow-white
-shells of these small snails constitute more than half of the mass of
-the tertiary limestone hills, and in this one locality show such an
-astonishing variety of forms, that the most divergent extremes might be
-referred to at least twenty entirely different species. But all these
-extreme forms are united by such innumerable intermediate forms, and
-they lie so regularly above and beside one another, that Hilgendorf was
-able, in the clearest manner, to unravel the pedigree of the whole group
-of forms. In like manner, among very many other fossil species (for
-example, many ammonites, terebratulæ, sea urchins, lily encrinites,
-etc.) there are such masses of connecting intermediate forms, that they
-reduce the "dealers in fossil species" to despair.
-
-When we weigh all the circumstances here mentioned, the number of which
-might easily be increased, it does not appear astonishing that the
-natural accounts or records of creation formed by petrifactions are
-extremely defective and incomplete. But nevertheless, the petrifactions
-actually discovered are of the greatest value. Their significance is of
-no less importance to the natural history of creation than the
-celebrated inscription on the Rosetta stone, and the decree of Canopus,
-are to the history of nations--to archæology and philology. Just as it
-has become possible by means of these two most ancient inscriptions to
-reconstruct the history of ancient Egypt, and to decipher all
-hieroglyphic writings, so in many cases a few bones of an animal, or
-imperfect impressions of a lower animal or vegetable form, are
-sufficient for us to gain the most important starting-points in the
-history of the whole group, and in the search after their pedigree. A
-couple of small back teeth, which have been found in the Keuper
-formation of the Trias, have of themselves alone furnished a sure proof
-that mammals existed even in the Triassic period.
-
-Of the incompleteness of the geological accounts of creation, Darwin,
-agreeing with Lyell, the greatest of all recent geologists, says:--
-
-"I look at the geological record as a history of the world imperfectly
-kept, and written in a changing dialect; of this history we possess the
-last volume alone, relating only to two or three countries. Of this
-volume, only here and there a short chapter has been preserved; and of
-each page, only here and there a few lines. Each word of the
-slowly-changing language, more or less different in the successive
-chapters, may represent the forms of life which are entombed in our
-consecutive formations, and which falsely appear to us to have been
-abruptly introduced. On this view, the difficulties above discussed are
-greatly diminished, or even disappear."--_Origin of Species_, 6th
-Edition, p. 289.
-
-If we bear in mind the exceeding incompleteness of palæontological
-records, we shall not be surprised that we are still dependent upon so
-many uncertain hypotheses when actually endeavouring to sketch the
-pedigree of the different organic groups. However, we fortunately
-possess, besides fossils, other records of the history of the origin of
-organisms, which in many cases are of no less value, nay, in several
-cases are of much greater value, than fossils. By far the most important
-of these other records of creation is, without doubt, _ontogeny_, that
-is, the history of the development of the organic individual (embryology
-and metamorphology). It briefly repeats in great and marked features the
-series of forms which the ancestors of the respective individuals have
-passed through from the beginning of their tribe. We have designated the
-palæontological history of the development of the ancestors of a living
-form as the history of a tribe, or _phylogeny_, and we may therefore
-thus enunciate this exceedingly important _biogenetic fundamental
-principle_: "_Ontogeny is a short and quick repetition, or
-recapitulation, of Phylogeny, determined by the laws of Inheritance and
-Adaptation_." As every animal and every plant from the beginning of its
-individual existence passes through a series of different forms, it
-indicates in rapid succession and in general outlines the long and
-slowly changing series of states of form which its progenitors have
-passed through from the most ancient times. (Gen. Morph. ii. 6, 110,
-300.)
-
-It is true that the sketch which the ontogeny of organisms gives us of
-their phylogeny is in most cases more or less obscured, and all the more
-so the more Adaptation, in the course of time, has predominated over
-Inheritance, and the more powerfully the law of abbreviated inheritance,
-and the law of correlative adaptation, have exerted their influence.
-However, this does not lessen the great value which the actual and
-faithfully preserved features of that sketch possess. _Ontogeny is of
-the most inestimable value for the knowledge of the earliest
-palæontological conditions of development_, just because no petrified
-remains of the most ancient conditions of the development of tribes and
-classes have been preserved. These, indeed, could not have been
-preserved on account of the soft and tender nature of their bodies. No
-petrifactions could inform us of the fundamental and important fact
-which ontogeny reveals to us, that the most ancient common ancestors of
-all the different animal and vegetable species were quite simple cells
-like the egg-cell. No petrifaction could prove to us the immensely
-important fact, established by ontogeny, that the simple increase, the
-formation of cell-aggregates and the differentiation of those cells,
-produced the infinitely manifold forms of multicellular organisms. Thus
-ontogeny helps us over many and large gaps in palæontology.
-
-[Illustration: Hand of Nine different Mammals. Pl. IV.
-
-_1. Man_, _2. Gorilla_, _3. Orang_, _4. Dog_, _5. Seal_, _6. Porpoise_,
-_7. Bat_, _8. Mole_, _9. Duck-bill_.]
-
-To the invaluable records of creation furnished by palæontology and
-ontogeny are added the no less important evidences for the blood
-relationship of organisms furnished by _comparative anatomy_. When
-organisms, externally very different, nearly agree in their internal
-structure, one may with certainty conclude that the agreement has its
-foundation in Inheritance, the dissimilarity its foundation in
-Adaptation. Compare, for example, the hands and fore paws of the nine
-different animals which are represented on Plate IV., in which the bony
-skeleton in the interior of the hand and of the five fingers is visible.
-Everywhere we find, though the external forms are most different, the
-same bones, and among them the same number, position, and connection. It
-will perhaps appear very natural that the hand of _man_ (Fig. 1) differs
-very little from that of the _gorilla_ (Fig. 2) and of the
-_orang-outang_ (Fig. 3), his nearest relations. But it will be more
-surprising if the fore feet of the _dog_ also (Fig. 4), as well as the
-breast-fin (the hand) of the _seal_ (Fig. 5), and of the _dolphin_ (Fig.
-6), show essentially the same structure. And it will appear still more
-wonderful that even the wing of the _bat_ (Fig. 7), the shovel-feet of
-the _mole_ (Fig. 8), and the fore feet of the _duck-bill_
-(Ornithorhynchus) (Fig. 9), the most imperfect of all mammals, is
-composed of entirely the same bones, only their size and form being
-variously changed. Their number, the manner of their arrangement and
-connection has remained the same. (Compare also the explanation of Plate
-IV., in the Appendix.) It is quite inconceivable that any other cause,
-except the common inheritance of the part in question from common
-ancestors, could have occasioned this wonderful homology or similarity
-in the essential inner structure with such different external forms.
-Now, if we go down further in the system below the mammals, and find
-that even the wings of birds, the fore feet of reptiles and amphibious
-animals, are composed of essentially the same bones as the arms of man
-and the fore legs of the other mammals, we can, from this circumstance
-alone, with perfect certainty, infer the common origin of all these
-vertebrate animals. Here, as in all other cases, the degree of the
-internal agreement in the form discloses to us the degree of blood
-relationship.
-
-
-
-
-CHAPTER XVI.
-
-PEDIGREE AND HISTORY OF THE KINGDOM OF THE PROTISTA.
-
-
-  Special Mode of Carrying out the Theory of Descent in the
-  Natural System of Organisms.--Construction of Pedigrees.--Descent
-  of all Many-Celled from Single-Celled Organisms.--Descent of
-  Cells from Monera.--Meaning of Organic Tribes, or Phyla.--Number
-  of the Tribes in the Animal and Vegetable Kingdoms.--The
-  Monophyletic Hypothesis of Descent, or the Hypothesis of one
-  Common Progenitor, and the Polyphyletic Hypothesis of Descent,
-  or the Hypothesis of Many Progenitors.--The Kingdom of Protista,
-  or Primæval Beings.--Eight Classes of the Protista
-  Kingdom.--Monera, Amoebæ, or Protoplastæ.--Whip-swimmers, or
-  Flagellata.--Ciliated-balls, or Catallacta.--Labyrinth-streamers,
-  or Labyrinthuleæ.--Flint-cells, or Diatomeæ.--Mucous-moulds, or
-  Myxomycetes.--Root-footers (Rhizopoda).--Remarks on the General
-  Natural History of the Protista: Their Vital Phenomena,
-  Chemical Composition, and Formation (Individuality and
-  Fundamental Form).--Phylogeny of the Protista Kingdom
-
-
-By a careful comparison of the individual and the palæontological
-development, as also by the comparative anatomy of organisms, by the
-comparative examination of their fully developed structural
-characteristics, we arrive at the knowledge of the degrees of their
-different structural relationships. By this, however, we at the same
-time obtain an insight into their true _blood relationship_, which,
-according to the Theory of Descent, is the real reason of the structural
-relationship. Hence by collecting, comparing, and employing the
-empirical results of embryology, palæontology, and anatomy for
-supplementing each other, we arrive at an approximate knowledge of "the
-Natural System," which, according to our views, is the _pedigree_ of
-organisms. It is true that our human knowledge, in all things
-fragmentary, is especially so in this case, on account of the extreme
-incompleteness and defectiveness of the records of creation. However, we
-must not allow this to discourage us, or to deter us from undertaking
-this highest problem of biology. Let us rather see how far it may even
-now be possible, in spite of the imperfect state of our embryological,
-palæontological, and anatomical knowledge, to establish a probable
-scheme of the genealogical relationships of organisms.
-
-Darwin in his book gives us no answer to these special questions of the
-Theory of Descent; at the conclusion he only expresses his conjecture
-"that animals have descended from at most only four or five progenitors,
-and plants from an equal or less number." But as these few aboriginal
-forms still show traces of relationship, and as the animal and vegetable
-kingdoms are connected by intermediate transitional forms, he arrives
-afterwards at the opinion "that probably all the organic beings which
-have ever lived on the earth have descended from some one primordial
-form, into which life was first breathed by the Creator." Like Darwin,
-all other adherents of the Theory of Descent have only treated it in a
-general way, and not made the attempt to carry it out specially, and to
-treat the "Natural System" actually as the pedigree of organisms. If,
-therefore, we venture upon this difficult undertaking, we must take up
-independent ground.
-
-Four years ago I set up a number of hypothetical genealogies for the
-larger groups of organisms in the systematic introduction to my General
-History of Development (Gen. Morph. vol. ii.), and thereby, in fact,
-made the first attempt actually to construct the pedigrees of organisms
-in the manner required by the theory of development. I was quite
-conscious of the extreme difficulty of the task, and as I undertook it
-in spite of all discouraging obstacles, I claim no more than the merit
-of having made the first attempt and given a stimulus for other and
-better attempts. Probably most zoologists and botanists were but little
-satisfied with this beginning, and least so in reference to the special
-domain in which each one is specially at work. However, it is certainly
-in this case much easier to blame than to produce something better, and
-what best proves the immense difficulty of this infinitely complicated
-task is the fact that no naturalist has as yet supplied the place of my
-pedigrees by better ones. But, like all other scientific hypotheses
-which serve to explain facts, my genealogical hypotheses may claim to be
-taken into consideration until they are replaced by better ones.
-
-I hope that this replacement will very soon take place; and I wish for
-nothing more than that my first attempt may induce very many naturalists
-to establish more accurate pedigrees for the individual groups, at least
-in the special domain of the animal and vegetable kingdom which happens
-to be well known to one or other of them. By numerous attempts of this
-kind our genealogical knowledge, in the course of time, will slowly
-advance and approach more towards perfection, although it can with
-certainty be foreseen that we shall never arrive at a complete
-pedigree. We lack, and shall ever lack, the indispensable
-palæontological foundations. The most ancient records will ever remain
-sealed to us, for reasons which have been previously mentioned. The most
-ancient organisms which arose by spontaneous generation--the original
-parents of all subsequent organisms--must necessarily be supposed to
-have been Monera--simple, soft, albuminous lumps, without structure,
-without any definite forms, and entirely without any hard and formed
-parts. They and their next offspring were consequently not in any way
-capable of being preserved in a petrified condition. But we also lack,
-for reasons discussed in detail in the preceding chapter, by far the
-greater portion of the innumerable palæontological documents, which are
-really requisite for a safe reconstruction of the history of animal
-tribes, or phylogeny, and for the true knowledge of the pedigree of
-organisms. If we, therefore, in spite of this, venture to undertake
-their hypothetical construction, we must chiefly depend for guidance on
-the two other series of records which most essentially supplement the
-palæontological archives. These are ontogeny and comparative anatomy.
-
-If thoughtfully and carefully we consult these most valuable records, we
-at once perceive what is exceedingly significant, namely, that by far
-the greater number of organisms, especially all higher animals and
-plants, are composed of a great number of cells, and that they originate
-out of an egg, and that this egg, in animals as well as in plants, is a
-single, perfectly simple cell--a little lump of albuminous constitution,
-in which another albuminous corpuscle, the cell-kernel, is enclosed.
-This cell containing its kernel grows and becomes enlarged. By division
-it forms an accumulation of cells, and out of these, by division of
-labour (as has previously been described), there arise the numberless
-different forms which are presented to us in the fully developed animal
-and vegetable species. This immensely important process--which we may
-follow step by step, with our own eyes, any day in the embryological
-development of any animal or vegetable individual, and which as a rule
-is by no means considered with the reverence it deserves--informs us
-more surely and completely than all petrifactions could do as to the
-original palæontological development of all many-celled organisms, that
-is, of all higher animals and plants. For as ontogeny, or the
-embryological development of every single individual, is essentially
-only a recapitulation of phylogeny, or the palæontological development
-of its chain of ancestors, we may at once, with full assurance, draw the
-simple and important conclusion, that _all many-celled animals and
-plants were originally derived from single-celled organisms_. The
-primæval ancestors of man, as well as of all other animals, and of all
-plants composed of many cells, were simple cells living isolated. This
-invaluable secret of the organic pedigree is revealed to us with
-infallible certainty by the egg of animals, and by the true egg-cell of
-plants. When the opponents of the Theory of Descent assert it to be
-miraculous and inconceivable that an exceedingly complicated many-celled
-organism could, in the course of time, have proceeded from a simple
-single-celled organism, we at once reply that we may see this incredible
-miracle at any moment, and follow it with our own eyes. For the
-embryology of animals and plants visibly presents to our eyes in the
-shortest space of time the same process as that which has taken place in
-the origin of the whole tribe during the course of enormous periods of
-time.
-
-Upon the ground of embryological records, therefore, we can with full
-assurance maintain that all many-celled, as well as single-celled,
-organisms are originally descended from simple cells; connected with
-this, of course, is the conclusion that the most ancient root of the
-animal and vegetable kingdom was common to both. For the different
-primæval "original cells" out of which the few different main groups or
-tribes have developed, only acquired their differences after a time, and
-were descended from a common "primæval cell." But where did those few
-"original cells," or the one primæval cell, come from? For the answer to
-this fundamental genealogical question we must return to the theory of
-plastids and the hypothesis of spontaneous generation which we have
-already discussed (vol. i. p. 327).
-
-As was then shown, we cannot imagine _cells_ to have arisen by
-spontaneous generation, but only _Monera_, those primæval creatures of
-the simplest kind conceivable, like the still living Protamoebæ,
-Protomyxæ, etc. (vol. i. p. 186, Fig. 1). Only such corpuscules of mucus
-without component parts--whose whole albuminous body is as homogeneous
-in itself as an inorganic crystal, but which nevertheless fulfills the
-two organic fundamental functions of nutrition and propagation--could
-have directly arisen out of inorganic matter by autogeny at the
-beginning (we may suppose) of the Laurentian period. While some Monera
-remained at the original simple stage of formation, others gradually
-developed into cells by the inner kernel of the albuminous mass becoming
-separated from the external cell-substance. In others, by
-differentiation of the outermost layer of the cell-substance, an
-external covering (membrane, or skin) was formed round simple cytods
-(without kernel), as well as round naked cells (containing a kernel). By
-these two processes of separation in the simple primæval mucus of the
-Moneron body, by the formation of a kernel in the interior and a
-covering on the outer surface of the mass of plasma, there arose out of
-the original most simple cytods, or Monera, those four different species
-of plastids, or individuals, of the first order, from which, by
-differentiation and combination, all other organisms could afterwards
-develop themselves. (Compare vol. i. p. 347.)
-
-The question now forces itself upon us, Are all organic cytods and
-cells, and consequently also those "original cells" which we previously
-considered to be the primary parents of the few great main groups of the
-animal and vegetable kingdoms, descended from a single original form of
-Moneron, or were there several different organic primary forms, each
-traceable to a peculiar independent species of Moneron which originated
-by spontaneous generation? In other words, _Is the whole organic world
-of a common origin, or does it owe its origin to several acts of
-spontaneous generation?_ This fundamental question of genealogy seems at
-first sight to be of exceeding importance. But on a more accurate
-examination, we shall soon see that this is not the case, and that it is
-in reality a matter of very subordinate importance.
-
-Let us now pass on to examine and clearly limit our conception of an
-_organic tribe_. By _tribe_, or _phylum_, we understand all those
-organisms of whose blood relationship and descent from a common primary
-form there can be no doubt, or whose relationship, at least, is most
-probable from anatomical reasons, as well as from reasons founded on
-historical development. Our tribes, or phyla, according to this idea,
-essentially coincide with those few "great classes," or "main classes,"
-of which Darwin also thinks that each contains only organisms related by
-blood, and of which, both in the animal and in the vegetable kingdoms,
-he only assumes either four or five. In the animal kingdom these tribes
-would essentially coincide with those four, five, or six main divisions
-which zoologists, since Bär and Cuvier, have distinguished as "main
-forms, general plans, branches, or sub-kingdoms" of the animal kingdom.
-(Compare vol. i. p. 53.) Bär and Cuvier distinguished only four of them,
-namely:--1. The vertebrate animals (Vertebrata); 2. The articulated
-animals (Articulata); 3. The molluscous animals (Mollusca); and 4. The
-radiated animals (Radiata). At present six are generally distinguished,
-since the tribe of the articulated animals is divided into two tribes,
-those possessing articulated feet (Arthropoda), and the worms (Vermes);
-and in like manner the tribe of radiated animals is subdivided into the
-two tribes of the star animals (Echinodermata) and the animal-plants
-(Zoophyta). Within each of these six tribes, all the included animals,
-in spite of great variety in external form and inner structure,
-nevertheless possess such numerous and important characteristics in
-common, that there can be no doubt of their blood relationship. The same
-applies also to the six great main classes which modern botany
-distinguishes in the vegetable kingdom, namely:--1. Flowering plants
-(Phanerogamia); 2. Ferns (Filicinæ); 3. Mosses (Muscinæ); 4. Lichens
-(Lichenes); 5. Fungi (Fungi); and 6. Water-weeds (Algæ). The last three
-groups, again, show such close relations to one another, that by the
-name of "Thallus plants" they may be contrasted with the three first
-main classes, and consequently the number of phyla, or main groups, of
-the vegetable kingdom may be reduced to the number of four. Mosses and
-ferns may likewise be comprised as "Prothallus plants" (Prothallophyta),
-and thereby the number of plant tribes reduced to three--Flowering
-plants, Prothallus plants, and Thallus plants.
-
-Very important facts in the anatomy and the history of development, both
-in the animal and vegetable kingdoms, support the supposition that even
-these few main classes or tribes are connected at their roots, that is,
-that the lowest and most ancient primary forms of all three are related
-by blood to one another. Nay, by a further examination we are obliged to
-go still a step further, and to agree with Darwin's supposition, that
-even the two pedigrees of the animal and vegetable kingdom are connected
-at their lowest roots, and that the lowest and most ancient animals and
-plants are derived from a single common primary creature. According to
-our view, this common primæval organism can have been nothing but a
-Moneron which took its origin by spontaneous generation.
-
-In the mean time we shall at all events be acting cautiously if we avoid
-this last step, and assume true blood relationship only within each
-tribe, or phylum, where it has been undeniably and surely established by
-facts in comparative anatomy, ontogeny, and phylogeny. But we may here
-point to the fact that two different fundamental forms of genealogical
-hypothesis are possible, and that all the different investigations of
-the Theory of Descent in relation to the origin of organic groups of
-forms will, in future, tend more and more in one or the other of these
-directions. The unitary, or _monophyletic_, hypothesis of descent will
-endeavour to trace the first origin of all individual groups of
-organisms, as well as their totality, to a single common species of
-Moneron which originated by spontaneous generation (vol. i. p. 343). The
-multiple, or _polyphyletic_, hypothesis of descent, on the other hand,
-will assume that several different species of Monera have arisen by
-spontaneous generation, and that these gave rise to several different
-main classes (tribes, or phyla) (vol. i. p. 348). The apparently great
-contrast between these two hypotheses is in reality of very little
-importance. For both the monophyletic and the polyphyletic hypothesis of
-descent must necessarily go back to the Monera as the most ancient root
-of the one or of the many organic tribes. But as the whole body of a
-Moneron consists only of a simple, formless mass, without component
-particles, made up of a single albuminous combination of carbon, it
-follows that the differences of the different Monera can only be of a
-chemical nature, and can only consist in a different atomic composition
-of that mucous albuminous combination. But these subtle and complicated
-differences of mixture of the infinitely manifold combinations of
-albumen are not appreciable by the rude and imperfect means of human
-observation and are, consequently, at present of no further interest to
-the task we have in hand.
-
-The question of the monophyletic or polyphyletic origin will constantly
-recur within each individual tribe, where the origin of a smaller or of
-a larger group is discussed. In the vegetable kingdom, for example, some
-botanists will be inclined to derive all flowering plants from a single
-form of fern, while others will prefer the idea that several different
-groups of Phanerogama have sprung from several different groups of
-ferns. In like manner, in the animal kingdom, some zoologists will be
-more in favour of the supposition that all placental animals are derived
-from a single pouched animal; others will be more in favour of the
-opposite supposition, that several different groups of placental animals
-have proceeded from several different pouched animals. In regard to the
-human race itself, some will prefer to derive it from a single form of
-ape, while others will be more inclined to the idea that several
-different races of men have arisen, independently of one another, out of
-several different species of ape. Without here expressing our opinion in
-favour of either the one or the other conception, we must, nevertheless,
-remark that in general _the monophyletic hypothesis of descent deserves
-to be preferred to the polyphyletic hypothesis of descent_. In
-accordance with the chorological proposition of a single "centre of
-creation" or of a single primæval home for most species (which has
-already been discussed), we may be permitted to assume that the original
-form of every larger or smaller natural group only originated _once_ in
-the course of time, and only in _one part_ of the earth. We may safely
-assume this simple original root, that is, the monophyletic origin, in
-the case of all the more highly developed groups of the animal and
-vegetable kingdoms. (Compare vol. i. p. 353.) But it is very possible
-that the more complete Theory of Descent of the future will involve the
-polyphyletic origin of very many of the low and imperfect groups of the
-two organic kingdoms.
-
-For these reasons I consider it best, in the mean time, to adopt the
-_monophyletic hypothesis of descent_ both for the animal and for the
-vegetable kingdom. Accordingly, the above-mentioned six tribes, or
-phyla, of the animal kingdom must be connected at their lowest root,
-and likewise the three or six main classes, or phyla, of the vegetable
-kingdom must be traced to a common and most ancient original form. How
-the connection of these tribes is to be conceived I shall explain in the
-succeeding chapters. But before proceeding to this, we must occupy
-ourselves with a very remarkable group of organisms, which cannot
-without artificial constraint be assigned either to the pedigree of the
-vegetable or to that of the animal kingdom. These interesting and
-important organisms are the _primary creatures_, or _Protista_.
-
-All organisms which we comprise under the name of Protista show in their
-external form, in their inner structure, and in all their vital
-phenomena, such a remarkable mixture of animal and vegetable properties,
-that they cannot with perfect justice be assigned either to the animal
-or to the vegetable kingdom; and for more than twenty years an endless
-and fruitless dispute has been carried on as to whether they are to be
-assigned to this or that kingdom. Most of Protista are so small that
-they can scarcely, if at all, be perceived with the naked eye. Hence the
-majority of them have only become known during the last fifty years,
-since by the help of the improved and general use of the microscope
-these minute organisms have been more frequently observed and more
-accurately examined. However, no sooner were they better known than
-endless disputes arose about their real nature and their position in the
-natural system of organisms. Many of these doubtful primary creatures
-botanists defined as animals, and zoologists as plants; neither of the
-two would own them. Others, again, were declared by botanists to be
-plants, and by zoologists to be animals; each claimed them. These
-contradictions are not altogether caused by our imperfect knowledge of
-the Protista, but in reality by their true nature. Indeed, most Protista
-present such a confused mixture of several animal and vegetable
-characteristics, that each investigator may arbitrarily assign them
-either to the animal or vegetable kingdom. Accordingly as he defines
-these two kingdoms, and as he looks upon this or that characteristic as
-determining the animal or vegetable nature, he will assign the
-individual classes of Protista in one case to the animal and in another
-to the vegetable kingdom. But this systematic difficulty has become an
-inextricable knot by the fact that all more recent investigations on the
-lowest organisms have completely effaced, or at least destroyed, the
-sharp boundary between the animal and vegetable kingdom which had
-hitherto existed, and to such a degree that its restoration is possible
-only by means of a completely artificial definition of the two kingdoms.
-But this definition could not be made so as to apply to many of the
-Protista.
-
-For this and other reasons it is, in the mean time, best to exclude the
-doubtful beings from the animal as well as from the vegetable kingdom,
-and to comprise them in a third organic kingdom standing midway between
-the two others. This intermediate kingdom I have established as the
-_Kingdom of the Primary Creatures_ (Protista), when discussing general
-anatomy in the first volume of my General Morphology, pp. 191-238. In my
-Monograph of the Monera,(15) I have recently treated of this kingdom,
-having somewhat changed its limits, and given it a more accurate
-definition. Of independent classes of the kingdom Protista, we may at
-present distinguish the following:--
-
-1. The still living Monera; 2. The Amoeboidea, or Protoplasts; 3. The
-Whip-swimmers, or Flagellata; 4. The Flimmer-balls, or Catallacta; 5.
-The Tram-weavers, or Labyrinthuleæ; 6. The Flint-cells, or Diatomeæ; 7.
-The Slime-moulds, or Myxomycetes; 8. The Ray-streamers, or Rhizopoda.
-
-The most important groups at present distinguishable in these eight
-classes of Protista are named in the systematic table on p. 51. Probably
-the number of these Protista will be considerably increased in future
-days by the progressive investigations of the ontogeny of the simplest
-forms of life, which have only lately been carried on with any great
-zeal. With most of the classes named we have become intimately
-acquainted only during the last ten years. The exceedingly interesting
-Monera and Labyrinthuleæ, as also the Catallacta, were indeed discovered
-only a few years ago. It is probable also that very numerous groups of
-Protista have died out in earlier periods, without having left any
-fossil remains, owing to the very soft nature of their bodies. We might
-add to the Protista from the still living lowest groups of
-organisms--the Fungi; and in so doing should make a very large addition
-to its domain. Provisionally we shall leave them among plants, though
-many naturalists have separated them altogether from the vegetable
-kingdom.
-
-_The pedigree of the kingdom Protista_ is still enveloped in the
-greatest obscurity. The peculiar combination of animal and vegetable
-properties, the indifferent and uncertain character of their relations
-of forms and vital phenomena, together with a number of several very
-peculiar features which separate most of the subordinate classes sharply
-from the others, at present baffle every attempt distinctly to make out
-their blood relationships with one another, or with the lowest animals
-on the one hand, and with the lowest plants on the other hand. It is not
-improbable that the classes specified, and many other unknown classes of
-Protista, represent quite independent organic tribes, or phyla, each of
-which has independently developed from one, perhaps from various, Monera
-which have arisen by spontaneous generation. If we do not agree to this
-polyphyletic hypothesis of descent, and prefer the monophyletic
-hypothesis of the blood relationship of all organisms, we shall have to
-Look upon the different classes of protista as the lower small
-off-shoots of the root, springing from the same simple monera root, out
-of which arose the two mighty and many-branched pedigrees of the animal
-kingdom on the one hand, and of the vegetable kingdom on the other.
-(compare pp. 74, 75.) before i enter into this difficult question more
-accurately, it will be appropriate to premise something further as to
-the contents of the classes of protista given on the next page, and
-their general natural history.
-
-
-SYSTEMATIC SURVEY
-
-_Of the Larger and Smaller Groups of the Kingdom Protista._
-
-  ----------------+--------------------+------------------+-----------------
-   _Classes of    | _Systematic Name   | _Orders of       |  _A name of a
-   the Protista   |  of the Classes_.  | Families of the  |  Genus
-   Kingdom._      |                    | Classes._        |  as an example._
-  ----------------+--------------------+------------------+-----------------
-                                       { 1. Gymnomonera      Protogenes
-  1. MONERS             Monera         { 2. Lepomonera       Protomyxa
-
-                                       { 1. Gymnamoebæ       Amoeba
-  2. PROTOPLASTS        Amoeboida      { 2. Leptamoebæ       Arcella
-                                       { 3. Gregarinæ        Monocystis
-
-                                       { 1. Nudiflagellata   Euglena
-  3. WHIP-SWIMMERS      Flagellata     { 2. Cilioflagellata  Peridinium
-
-  4. FLIMMER-BALLS      Catallacta       1. Catallacta       Magosphæra
-
-  5. TRAM-WEAVERS       Labyrinthuleæ    1. Labyrinthuleæ    Labyrinthula
-
-                                       { 1. Striata          Navicula
-  6. FLINT-CELLS        Diatomea       { 2. Vittata          Tabellaria
-                                       { 3. Areolata         Coscinodiscus
-
-                                       { 1. Physareæ         Æthalium
-  7. SLIME-MOULDS       Myxomycetes    { 2. Stemoniteæ       Stemonitis
-                                       { 3. Trichiaceæ       Arcyria
-                                       { 4. Lycogaleæ        Reticularia
-
-                    {   I. Acyttaria   { 1. Monothalamia     Gromia
-                    {                  { 2. Polythalamia     Nummulina
-  8. RAY-STREAMERS  {
-     OR RHIZOPODS.  {  II. Heliozoa      1. Heliozoa         Actinosphærium
-     (Root-feet)    {
-                    {                  { 1. Monocyttaria     Cyrtidosphæra
-                    { III. Radiolaria  { 2. Polycyttaria     Collosphæra
-
-
-[Illustration: FIG. 8.--Protamoeba primitiva, a fresh-water Moneron,
-much enlarged. _A._ The entire Moneron with its form-changing processes.
-_B._ It begins to divide itself into two halves. _C._ The division of
-the two halves is completed, and each now represents an independent
-individual.]
-
-It will perhaps seem strange that I should here again begin with the
-remarkable _Monera_ as the first class of the Protista kingdom, as I of
-course look upon them as the most ancient primary forms of all organisms
-without exception. Still, what are we otherwise to do with the _still
-living Monera_? We know nothing of their palæontological origin, we know
-nothing of any of their relations to lower animals or plants, and we
-know nothing of their possible capability of developing into higher
-organisms. The simple and homogeneous little lump of slime or mucus
-which constitutes their entire body (Fig. 8) is the most ancient and
-original form of animal as well as of vegetable plastids. Hence it would
-evidently be just as arbitrary and unreasonable to assign them to the
-animal as it would be to assign them to the vegetable kingdom. In any
-case we shall for the present be acting more cautiously and critically
-if we comprise the still living Monera--whose number and distribution is
-probably very great--as a special and independent class, contrasting
-them with the other classes of the kingdom Protista, as well as with the
-animal kingdom. Morphologically considered, the Monera--on account of
-the perfect homogeneity of the albuminous substance of their bodies, on
-account of their utter want of heterogeneous particles--are more closely
-connected with anorgana than with organisms, and evidently form the
-transition between the inorganic and organic world of bodies, as is
-necessitated by the hypothesis of spontaneous generation. I have
-described and given illustrations of the forms and vital phenomena of
-the still living Monera (Protamoeba, Protogenes, Protomyxa, etc.) in my
-Monograph of the Monera,(15) and have briefly mentioned the most
-important facts in the eighth chapter (vol. i. pp. 183-187). Therefore,
-only by way of a specimen, I here repeat the drawing of the fresh-water
-Protamoeba (Fig. 8). The history of the life of an orange-red _Protomyxa
-adrantiaca_, which I observed at Lanzerote, one of the Canary Islands,
-is given in Plate I. (see its explanation in the Appendix). Besides
-this, I here add a drawing of the form of Bathybius, that remarkable
-Moneron discovered by Huxley, which lives in the greatest depths of the
-sea in the shape of naked lumps of protoplasm and reticular mucus (vol.
-i. p. 344).
-
-[Illustration: FIG. 9.--Bathybius Hæckelii, the "creature of primæval
-slime," from the greatest depths of the sea. The figure, which is
-greatly magnified, only shows that form of the Bathybius which consists
-of a naked network of protoplasm, without the discoliths and cyatholiths
-which are found in other forms of the same Moneron, and which perhaps
-may be considered as the products of its secretion.]
-
-The _Amoebæ_ of the present day, and the organisms most closely
-connected with them, _Arcellidæ_ and _Gregarinæ_, which we here unite as
-a second class of Protista under the name of _Amoeboidea_ (Protoplasta),
-present no fewer genealogical difficulties than the Monera. These
-primary creatures are at present usually placed in the animal kingdom
-without its in reality being understood why. For simple naked
-cells--that is, shell-less plastids with a kernel--occur as well among
-real plants as real animals. The generative cells, for example, in many
-Algæ (spores and eggs) exist for a longer or shorter time in water in
-the form of naked cells with a kernel, which cannot be distinguished at
-all from the naked eggs of many animals (for example, those of the
-Siphonophorous Medusæ). (Compare the figure of a naked egg of a
-bladder-wrack in Chapter xvii. p. 90.) In reality every naked simple
-cell, whether it proceeds from an animal or vegetable body, cannot be
-distinguished from an independent Amoeba. For an Amoeba is nothing but a
-simple primary cell, a naked little lump of cell-matter, or plasma,
-containing a kernel. The contractility of this plasma, which the free
-Amoeba shows in stretching out and drawing in its changing processes, is
-a general vital property of the organic plasma of all animal as well as
-of all vegetable plastids. When a freely moving Amoeba, which
-perpetually changes its form, passes into a state of rest, it draws
-itself together into the form of a globule, and surrounds itself with a
-secreted membrane. It can then be as little distinguished from an animal
-egg as from a simple globular vegetable cell (Fig. 10 _A_).
-
-[Illustration: FIG. 10.--Amoeba sphærococcus, greatly magnified. A
-fresh-water Amoeba without a contractile vacuole. _A._ The enclosed
-Amoeba in the state of a globular lump of plasma (_c_) enclosing a
-kernel and a kernel-speck (_a_). The simple cell is surrounded by a
-cyst, or cell membrane (_d_). _B._ The free Amoeba, which has burst and
-left the cyst, or cell-membrane. _C._ It begins to divide by its kernel
-parting into two kernels, and the cell-substance between the two
-contracting. _D._ The division is completed, and the cell-substance has
-entirely separated into two bodies. (_Da_ and _Db_).]
-
-Naked cells, with kernels, like those represented in Fig. 10 _B_, which
-are continuously changing, stretching out and drawing in formless,
-finger-like processes, and which are on this account called amoeboid,
-are found frequently and widely dispersed in fresh water and in the sea;
-nay, are even found creeping on land. They take their food in the same
-way as was previously described in the case of the Protamoeba (vol. i.
-p. 186). Their propagation by division can sometimes be observed. (Fig.
-10 _C_, _D_.) I have described the processes in an earlier chapter (vol.
-i. p. 187). Many of these formless Amoebæ have lately been recognized as
-the early stages of development of other Protista (especially the
-Myxomycetæ), or as the freed cells of lower animals and plants. The
-colourless blood-cells of animals, for example, those of human blood,
-cannot be distinguished from Amoebæ. They, like the latter, can receive
-solid corpuscles into their interior, as I was the first to show by
-feeding them with finely divided colouring matters (Gen. Morph. i. 271).
-However, other Amoebæ (like the one given in Fig. 10) seem to be
-independent "good species," since they propagate themselves unchanged
-throughout many generations. Besides the real, or _naked_, Amoebæ
-(Gymnamoebæ), we also find widely diffused in fresh water _case-bearing_
-Amoebæ (Lepamoebæ), whose naked plasma body is _partially_ protected by
-a more or less solid shell (Arcella), sometimes even by a case
-(Difflugia) composed of small stones. Lastly, we frequently find in the
-body of many lower animals parasitic Amoebæ (Gregarinæ), which, adapting
-themselves to a parasitic life, have surrounded their plasma-body with a
-delicate closed membrane.
-
-The simple naked Amoebæ are, next to the Monera, the most important of
-all organisms to the whole science of biology, and especially to general
-genealogy. For it is evident that the Amoebæ originally arose out of
-simple Monera (Protamoebæ), by the important process of segregation
-taking place in their homogeneous viscid body--the differentiation of an
-inner kernel from the surrounding plasma. By this means the great
-progress from a simple cytod (without kernel) into a real cell (with
-kernel) was accomplished (compare Fig. 8 _A_ and Fig. 10 _B_). As some
-of these cells at an early stage encased themselves by secreting a
-hardened membrane, they formed the first vegetable cells, while others,
-remaining naked, developed into the first aggregates of animal cells.
-The presence or absence of an encircling hard membrane forms the most
-important, although by no means the entire, difference of form between
-animal and vegetable cells. As vegetable cells even at an early stage
-enclose themselves within their hard, thick, and solid cellular shell,
-like that of the Amoebæ in a state of rest (Fig. 10 _A_), they remain
-more independent and less accessible to the influences of the outer
-world than are the soft animal cells, which are in most cases naked, or
-merely covered by a thin pliable membrane. But in consequence of this
-the vegetable cells cannot combine, as do the animal cells, for the
-construction of higher and composite fibrous tracts, for example, the
-nervous and muscular tissues. It is probable that, in the case of the
-most ancient single-celled organisms, there must have developed at an
-early stage the very important difference in the animal and vegetable
-mode of receiving food. The most ancient single-celled animals, being
-naked cells, could admit solid particles into the interior of their soft
-bodies, as do the Amoebæ (Fig. 10 _B_) and the colourless blood-cells;
-whereas the most ancient single-celled plants encased by their membranes
-were no longer able to do this, and could admit through it only fluid
-nutrition (by means of diffusion).
-
-[Illustration: FIG. 11.--A single Whip-swimmer (Euglena striata),
-greatly magnified. Above a thread-like lashing whip is visible; in the
-centre the round cellular kernel, with its kernel speck.]
-
-The _Whip-swimmers_ (Flagellata), which we consider as a third class of
-the kingdom Protista, are of no less doubtful nature than the Amoebæ.
-They often show as close and important relations to the vegetable as to
-the animal kingdom. Some Flagellata at an early stage, when freely
-moving about, cannot be distinguished from real plants, especially from
-the spores of many Algæ; whereas others are directly allied to real
-animals, namely, to the fringed Infusoria (Ciliata). The Flagellata are
-simple cells which live in fresh or salt water, either singly or united
-in colonies. The characteristic part of their body is a very movable
-simple or compound whip-like appendage (whip, or flagellum) by means of
-which they actively swim about in the water. This class is divided into
-two orders. Among the fringed whip-swimmers (Cilioflagellata) there
-exists, in addition to the long whip, a short fringe of vibrating hairs,
-which is wanting in the unfringed whip-swimmers (Nudoflagellata). To the
-former belong the flint-shelled yellow Peridinia, which are largely
-active in causing the phosphorescence of the sea; to the latter belong
-the green Euglenæ, immense masses of which frequently make our ponds in
-spring quite green.
-
-[Illustration: FIG. 12.--The Norwegian Flimmer-ball (Magosphæra planula)
-swimming by means of its vibratile fringes, as seen from the surface.]
-
-A very remarkable new form of Protista, which I have named
-_Flimmer-ball_ (Magosphæra), I discovered only three years ago (in
-September, 1869), on the Norwegian coast (Fig. 12), and have more
-accurately described in my Biological Studies(15) (p. 137, Plate V.).
-Off the island of Gis-oe, near Bergen, I found swimming about, on the
-surface of the sea, extremely neat little balls composed of a number
-(between thirty and forty) of fringed pear-shaped cells, the pointed
-ends of which were united in the centre like radii. After a time the
-ball dissolved. The individual cells swarmed about independently in the
-water like fringed Infusoria, or Ciliata. These afterwards sank to the
-bottom, drew their fringes into their bodies, and gradually changed into
-the form of creeping Amoebæ (like Fig 10 _B_). These last afterwards
-encased themselves (as in Fig. 10 _A_), and then divided by repeated
-halvings into a large number of cells (exactly as in the case of the
-cleavage of the egg, Fig. 6, vol. i. p. 299). The cells became covered
-with vibratile hairs, broke through the case enclosing them, and now
-again swam about in the shape of a fringed ball (Fig. 12). This
-wonderful organism, which sometimes appears like a simple Amoeba,
-sometimes as a single fringed cell, sometimes as a many-celled fringed
-ball, can evidently be classed with none of the other Protista, and must
-be considered as the representative of a new independent group. As this
-group stands midway between several Protista, and links them together,
-it may bear the name of _Mediator_, or _Catallacta_.
-
-[Illustration: FIG. 13.--Labyrinthula macrocystis (much enlarged). Below
-is a large group of accumulated cells, one of which, on the left, is
-separating itself; above are two single cells which are gliding along
-the threads of the retiform labyrinth which form their "tramways."]
-
-The Protista of the fifth class, the _Tram-weavers_, or _Labyrinthuleæ_,
-are of a no less puzzling nature; they were lately discovered by
-Cienkowski on piles in sea water (Fig. 13). They are spindle-shaped
-cells, mostly of a yellow-ochre colour, which are sometimes united into
-a dense mass, sometimes move about in a very peculiar way. They form, in
-a manner not yet explained, a retiform frame of entangled threads
-(compared to a labyrinth), and on the dense filamentous "tramways" of
-this frame they glide about. From the shape of the cells of the
-Labyrinthuleæ we might consider them as the simplest plants, from their
-motion as the simplest animals, but in reality they are neither animals
-nor plants.
-
-[Illustration: FIG. 14.--Navicula hippocampus (greatly magnified). In
-the middle of the cell the cell-kernel (nucleus) is visible, together
-with its kernel speck (nucleolus).]
-
-The _Flint-cells_ (Diatomeæ), a sixth class of Protista, are perhaps the
-most closely related to the Labyrinthuleæ. These primary
-creatures--which at present are generally considered as plants, although
-some celebrated naturalists still look upon them as animals--inhabit the
-sea and fresh waters in immense masses, and offer an endless variety of
-the most elegant forms. They are mostly small microscopic cells, which
-either live singly (Fig. 14), or united in great numbers, and occur
-either attached to objects, or glide and creep about in a peculiar
-manner. Their soft cell-substance, which is of a characteristic brownish
-yellow colour, is always enclosed by a solid and hard flinty shell,
-possessing the neatest and most varied forms. This flinty covering is
-open to the exterior only by one or two slits, through which the
-enclosed soft plasma-body communicates with the outer world. The flinty
-cases are found petrified in masses, and many rocks--for example, the
-Tripoli slate polish, the Swedish mountain meal, etc.,--are in a great
-measure composed of them.
-
-A seventh class of Protista is formed by the remarkable _Slime-moulds_
-(Myxomycetes). They were formerly universally considered as plants, as
-real Fungi, until ten years ago the botanist De Bary, by discovering
-their ontogeny, proved them to be quite distinct from Fungi, and rather
-to be akin to the lower animals. The mature body is a roundish bladder,
-often several inches in size, filled with fine spore-dust and soft
-flakes (Fig. 15), as in the case of the well-known puff-balls
-(Gastromycetes). However, the characteristic cellular threads, or hyphæ,
-of a real fungus do not arise from the germinal corpuscles, or spores,
-of the Myxomycetes, but merely naked masses of plasma, or cells, which
-at first swim about in the form of Flagellata (Fig. 11), afterwards
-creep about like the Amoebæ (Fig. 10 _B_), and finally combine with
-others of the same kind to form large masses of "slime," or "plasmodia."
-Out of these, again, there arises, by-and-by, the bladder-shaped
-fruit-body. Many of my readers probably know one of these plasmodia, the
-Æthalium septicum, which in summer forms a beautiful yellow mass of soft
-mucus, often several feet in breadth, known by the name of "tan
-flowers," and penetrates tan-heaps and tan-beds. At an early stage these
-slimy, freely-creeping Myxomycetes, which live for the most part in damp
-forests, upon decaying vegetable substances, bark of trees, etc., are
-with equal justice or injustice declared by zoologists to be animals,
-while in the mature, bladder-shaped condition of fructification they are
-by botanists defined as plants.
-
-[Illustration: FIG. 15.--A stalked fruit-body (spore-bladder, filled
-with spores) of one of the Myxomycetes (Physarum albipes) not much
-enlarged.]
-
-The nature of the _Ray-streamers_ (Rhizopoda), the eighth class of the
-kingdom Protista, is equally obscure. These remarkable organisms have
-peopled the sea from the most ancient times of the organic history of
-the earth, in an immense variety of forms, sometimes creeping at the
-bottom of the sea, sometimes swimming on the surface. Only very few live
-in fresh water (Gromia, Actinosphærium). Most of them possess solid
-calcareous or flinty shells of an extremely beautiful construction,
-which can be perfectly preserved in a fossil state. They have frequently
-accumulated in such huge numbers as to form mountain masses, although
-the single individuals are very small, and often scarcely visible, or
-completely invisible to the naked eye. A very few attain the diameter
-of a few lines, or even as much as a couple of inches. The name which
-the class bears is given because thousands of exceedingly fine threads
-of protoplasm radiate from the entire surface of their naked slimy body;
-these rays are quasi-feet, or pseudopodia, which branch off like roots
-(whence the term Rhizopoda, signifying root-footed), unite like nets,
-and are observed continually to change form, as in the case of the
-simpler plasmic feet of the Amoeboidea, or Protoplasts. These
-ever-changing little pseudo-feet serve both for locomotion and for
-taking food.
-
-The class of the Rhizopoda is divided into three different legions, viz.
-the chamber-shells, or Acyttaria, the sun-animalcules, or Heliozoa, and
-the basket-shells, or Radiolaria. The _Chamber-shells_ (Acyttaria)
-constitute the first and lowest of these three legions; for the whole of
-their soft body consists merely of simple mucous or slimy cell-matter,
-or protoplasm, which has not differentiated into cells. However, in
-spite of this most primitive nature of body, most of the Acyttaria
-secrete a solid shell composed of calcareous earth, which presents a
-great variety of exquisite forms. In the more ancient and more simple
-Acyttaria this shell is a simple chamber, bell-shaped, tubular, or like
-the shell of a snail, from the mouth of which a bundle of plasmic
-threads issues. In contrast to these _single-chambered forms_
-(Monothalamia), the _many-chambered forms_ (Polythalamia)--to which the
-great majority of the Acyttaria belong--possess a house, which is
-composed in an artistic manner of numerous chambers. These chambers
-sometimes lie in a row one behind the other, sometimes in concentric
-circles or spirals, in the form of a ring round a central point, and
-then frequently one above another in many tiers, like the boxes of an
-amphitheatre. This formation, for example, is found in the nummulites,
-whose calcareous shells, of the size of a lentil, have accumulated to
-the number of millions, and form whole mountains on the shores of the
-Mediterranean. The stones of which some of the Egyptian pyramids are
-built consist of such nummulitic limestone. In most cases the chambers
-of the shells of the Polythalamia are wound round one another in a
-spiral line. The chambers are connected with one another by passages and
-doors, like rooms of a large palace, and are generally open towards the
-outside by numerous little windows, out of which the plasmic body can
-stream or strain forth its little pseudo-feet, or rays of slime, which
-are always changing form. But in spite of the exceedingly complicated
-and elegant structure of this calcareous labyrinth, in spite of the
-endless variety in the structure and the decoration of its numerous
-chambers, and in spite of the regularity and elegance of their
-execution, the whole of this artistic palace is found to be the secreted
-product of a perfectly formless, slimy mass, devoid of any component
-parts! Verily, if the whole of the recent anatomy of animal and
-vegetable textures did not support our theory of plastids, if all its
-important results did not unanimously corroborate the fact that the
-whole miracle of vital phenomena and vital forms is traceable to the
-active agency of the formless albuminous combinations of protoplasm, the
-Polythalamia alone would secure the triumph of that theory. For we may
-here at any moment, by means of the microscope, point out the wonderful
-fact, first established by Dujardin and Max Schulze, that the formless
-mucus of the soft plasma-body, this true "matter of life," is able to
-secrete the neatest, most regular, and most complicated structures. This
-secretive skill is simply a result of _inherited adaptation_, and by it
-we learn to understand how this same "primæval slime"--this same
-protoplasm--can produce in the bodies of animals and plants the most
-different and most complicated cellular forms.
-
-It is, moreover, a matter of special interest that the most ancient
-organism, the remains of which are found in a petrified condition,
-belongs to the Polythalamia. This organism is the "Canadian Life's-dawn"
-(_Eozoon canadense_), which has already been mentioned, and which was
-found a few years ago in the Ottawa formation (in the deepest strata of
-the Laurentian system), on the Ottawa river in Canada. If we expected to
-find organic remains at all in these most ancient deposits of the
-primordial period, we should certainly look for such of the most simple
-Protista as are covered with a solid shell, and in the organization of
-which the difference between animal and plant is as yet not indicated.
-
-We know of but few species of the _Sun-animalcules_ (Heliozoa), the
-second class of the Rhizopoda. One species is very frequently found in
-our fresh waters. It was observed even in the last century by a
-clergyman in Dantzig, Eichhorn by name, and it has been called after
-him, Actinosphærium Eichhornii. To the naked eye it appears as a
-gelatinous grey globule of mucus, about the size of a pin's head.
-Looking at it through the microscope, we see hundreds or thousands of
-fine mucous threads radiating from the central plasma body, and perceive
-that the inner layer of its cell-substance is different from the outer
-layer, which forms a bladder-like membrane. In consequence of its
-structure, this, the little sun-animalcule, although wanting a shell,
-really rises above the structureless Acyttaria, and forms the transition
-from these to the Radiolaria. The genus Cystophrys is of a nature akin
-to it.
-
-The _Basket-shells_ (Radiolaria) form the third and last class of the
-Rhizopoda. Their lower forms are closely allied to the Heliozoa and
-Acyttaria, whereas their higher forms rise far above them. They are
-essentially distinguished from both by the fact that the central part of
-their body is composed of many cells, and surrounded by a solid
-membrane. This closed "central capsule," generally of a globular shape,
-is covered by a mucous layer of plasma, out of which there radiate on
-all sides thousands of exceedingly fine threads, the branching and
-confluent so-called pseudopodia. Between these are scattered numerous
-yellow cells of unknown function, containing grains of starch. Most
-Radiolaria are characterized by a highly developed skeleton, which
-consists of flint, and displays a wonderful richness of the neatest and
-most curious forms. Sometimes this flinty skeleton forms a simple
-trellice-work ball (Fig. 16 _s_), sometimes a marvellous system of
-several concentric trelliced balls, encased in one another, and
-connected by radial staves. In most cases delicate spikes, which are
-frequently branched like a tree, radiate from the surface of the balls.
-In other cases the whole skeleton consists of only one flinty star, and
-is then generally composed of twenty staves, distributed according to
-definite mathematical laws, and united in a common central point. The
-skeletons of other Radiolaria again form symmetrical many-chambered
-structures, as in the case of the Polythalamia. Perhaps no other group
-of organisms develop in the formation of their skeletons such an amount
-of various fundamental forms, such geometrical regularity, and such
-elegant architecture. Most of the forms as yet discovered, I have given
-in the atlas accompanying my Monograph of the Radiolaria.(23) Here I
-shall only give as an example the picture of one of the simplest forms,
-the _Cyrtidosphæra echinoides_ of Nice. The skeleton in this case
-consists only of a simple trelliced ball (_s_), with short radial spikes
-(_a_), which loosely surround the central capsule (_c_). Out of the
-mucous covering, enclosing the latter, radiate a great number of
-delicate little pseudopodia (_p_), which are partly drawn back
-underneath the shell, and fused into a lumpy mass of mucus. Between
-these are scattered a number of yellow cells (_l_).
-
-[Illustration: FIG. 16.--Cyrtidosphæra echinoides, 400 times enlarged.
-_c._ Globular central capsule. _s._ Basket-work of the perforated flinty
-shell. _a._ Radial spikes, which radiate from the latter. _p._ The
-pseudo-feet radiating from the mucous covering surrounding the central
-capsule. _l._ Yellow globular cells, scattered between the latter,
-containing grains of starch.]
-
-Most Acyttaria live only at the bottom of the sea, on stones and
-seaweeds, or creep about in sand and mud by means of their pseudopodia,
-but most Radiolaria swim on the surface of the sea by means of long
-pseudopodia extending in all directions. They live together there in
-immense numbers, but are mostly so small that they have been almost
-completely overlooked, and have only become accurately known during the
-last fourteen years. Certain Radiolaria living in communities
-(Polycyttaria) form gelatinous lumps of some lines in diameter. On the
-other hand, most of those living isolated (Monocyttaria) are invisible
-to the naked eye; but still their petrified shells are found accumulated
-in such masses that in many places they form entire mountains; for
-example, the Nicobar Islands in the Indian Archipelago, and the Island
-of Barbadoes in the Antilles.
-
-As most readers are probably but little acquainted with the eight
-classes of the Protista just mentioned, I shall now add some further
-general observations on their natural history. The great majority of all
-Protista live in the sea, some swimming freely on the surface, some
-creeping at the bottom, and others attached to stones, shells, plants,
-etc. Many species of Protista also live in fresh water, but only a very
-small number on dry land (for example, Myxomycetes and some
-Protoplasta). Most of them can be seen only through the microscope,
-except when millions of individuals are found accumulated. Only a few of
-them attain a diameter of some lines, or as much as an inch. What they
-lack in size of body they make up for by producing astonishing numbers
-of individuals, and they very considerably influence in this way the
-economy of nature. The imperishable remains of dead Protista, for
-instance, the flinty shells of the Diatomeæ and Radiolaria and the
-calcareous shells of the Acyttaria, often form large rock masses.
-
-In regard to their _vital phenomena_, especially those of nutrition and
-propagation, some Protista are more allied to plants, others more to
-animals. Both in their mode of taking food and in the chemical changes
-of their living substance, they sometimes more resemble the lower
-animals, at others the lower plants. _Free locomotion_ is possessed by
-many Protista, while others are without it; but this does not constitute
-a characteristic distinction, as we know of undoubted animals which
-entirely lack free locomotion, and of genuine plants which possess it.
-All Protista have a _soul_--that is to say, are "animate"--as well as
-all animals and all plants. The soul's activity in the Protista
-manifests itself in their _irritability_, that is, in the movements and
-other changes which take place in consequence of mechanical, electrical,
-and chemical irritation of their contractile protoplasm. Consciousness
-and the capability of will and thought are probably wanting in all
-Protista. However, the same qualities are in the same degree also
-wanting in many of the lower animals, whereas many of the higher animals
-in these respects are scarcely inferior to the lower races of human
-beings. In the Protista, as in all other organisms, the activities of
-the soul are traceable to molecular motions in the protoplasm.
-
-The most important _physiological characteristic_ of the kingdom
-Protista lies in the exclusively _non-sexual propagation_ of all the
-organisms belonging to it. The higher animals and plants multiply almost
-exclusively in a sexual manner. The lower animals and plants multiply
-also, in many cases, in a non-sexual manner, by division, the formation
-of buds, the formation of germs, etc. But sexual propagation almost
-always exists by the side of it, and often regularly alternates with it
-in succeeding generations (Metagenesis, vol. i. p. 206). All Protista,
-on the other hand, propagate themselves exclusively in a non-sexual
-manner, and in fact, the distinction of the two sexes among them has not
-been effected--there are neither male nor female Protista.
-
-The Protista in regard to their vital phenomena stand midway between
-animals and plants, that is to say, between their lowest forms; and the
-same must be said in regard to the _chemical composition_ of their
-bodies. One of the most important distinctions between the chemical
-composition of animal and vegetable bodies consists in the
-characteristic formation of the skeleton. The skeleton, or the solid
-scaffolding of the body in most genuine plants, consists of a substance
-called cellulose, devoid of nitrogen, but secreted by the nitrogenous
-cell-substance, or protoplasm. In most genuine animals, on the other
-hand, the skeleton generally consists either of nitrogenous combinations
-(chitin, etc.) or of calcareous earth. In this respect some Protista are
-more like plants, others more like animals. In many of them the skeleton
-is principally or entirely formed of calcareous earth, which is met with
-both in animal and vegetable bodies. But the active vital substance in
-all cases is the mucous protoplasm.
-
-In regard to the _form_ of the Protista, it is to be remarked that the
-_individuality_ of their body almost always remains at an extremely low
-stage of development. Very many Protista remain for life simple plastids
-or individuals of the first order. Others, indeed, form colonies or
-republics of plastids by the union of several individuals. But even
-these higher individuals of the second order, formed by the combination
-of simple plastids, for the most part remain at a very low stage of
-development. The members of such communities among the Protista remain
-very similar one to another, and never, or only in a slight degree,
-commence a division of labour, and are consequently as little able to
-render their community fit for higher functions as are, for example, the
-savages of Australia. The community of the plastids remains in most
-cases very loose, and each single plastid retains in a great measure its
-own individual independence.
-
-A second structural characteristic, which next to their low stage of
-individuality especially distinguishes the Protista, is the low stage of
-development of their stereometrical fundamental forms. As I have shown
-in my theory of fundamental forms (in the fourth book of the General
-Morphology), a definite geometrical fundamental form can be pointed out
-in most organisms, both in the general form of the body and in the form
-of the individual parts. This ideal fundamental form, or type, which is
-determined by the number, position, combination, and differentiation of
-the component parts, stands in just the same relation to the _real_
-organic form as the ideal geometrical fundamental form of crystals does
-to their imperfect _real_ form. In most bodies and parts of the bodies
-of animals and plants this fundamental form is a pyramid. It is a
-regular pyramid in the so-called "regular radiate" forms, and an
-irregular pyramid in the more highly differentiated, so-called
-"bilaterally symmetrical" forms. (Compare the plates in the first volume
-of my General Morphology, pp. 556-558.) Among the Protista this
-pyramidal type, which prevails in the animal and vegetable kingdom, is
-on the whole rare, and instead of it we have either quite irregular
-(amorphous) or more simple, regular geometrical types; especially
-frequent are the sphere, the cylinder, the ellipsoid, the spheroid, the
-double cone, the cone, the regular polygon (tetrahedron, hexahedron,
-octahedron, dodecahedron, icosahedron), etc. All the fundamental forms
-of the pro-morphological system, which are of a low rank in that system,
-prevail in the Protista. However, in many Protista there occur also the
-higher, regular, and bilateral types, fundamental forms which
-predominate in the animal and vegetable kingdoms. In this respect some
-of the Protista are frequently more closely allied to animals (as the
-Acyttaria), others more so to plants (as the Radiolaria).
-
-With regard to the _palæontological development of the kingdom
-Protista_, we may form various, but necessarily very unsafe,
-genealogical hypotheses. Perhaps the individual classes of the kingdom
-are independent tribes, or phyla, which have developed independently of
-one another and independently of the animal and the vegetable kingdoms.
-Even if we adopt the monophyletic hypothesis of descent, and maintain a
-common origin from a single form of Moneron for all organisms, without
-exception, which ever have lived and still live upon the earth, even in
-this case the connection of the neutral Protista on the one hand with
-the vegetable kingdom, and on the other hand with the animal kingdom,
-must be considered as very vague. We must regard them (compare p. 74) as
-lower off-shoots which have developed directly out of the root of the
-great double-branched organic pedigree, or perhaps out of the lowest
-tribe of Protista, which may be supposed to have shot up midway between
-the two diverging high and vigorous trunks of the animal and vegetable
-kingdoms. The individual classes of the Protista, whether they are more
-closely connected at their roots in groups, or only form a loose bunch
-of root offsets, must in this case be regarded as having nothing to do
-either with the diverging groups of organisms belonging to the animal
-kingdom on the right, or to the vegetable kingdom on the left. They must
-be supposed to have retained the original simple character of the common
-primæval living thing more than have genuine animals and genuine plants.
-
-But if we adopt the polyphyletic hypothesis of descent, we have to
-imagine a number of organic tribes, or phyla, which all shoot up by
-spontaneous generation out of the same ground, by the side of and
-independent of one another. (Compare p. 75.) In that case numbers of
-different Monera must have arisen by spontaneous generation whose
-differences would depend only upon slight, to us imperceptible,
-differences in their chemical composition, and consequently upon
-differences in their capability of development. A small number of Monera
-would then have given origin to the animal kingdom, and, again, a small
-number would have produced the vegetable kingdom. Between these two
-groups, however, there would have developed, independently of them, a
-large number of independent tribes, which have remained at a lower stage
-of organization, and which have neither developed into genuine plants
-nor into genuine animals.
-
-A safe means of deciding between the monophyletic and polyphyletic
-hypotheses is as yet quite impossible, considering the imperfect state
-of our phylogenetic knowledge. The different groups of Protista, and
-those lowest forms of the animal kingdom and of the vegetable kingdom
-which are scarcely distinguishable from the Protista, show such a close
-connection with one another and such a confused mixture of
-characteristics, that at present any systematic division and arrangement
-of the groups of forms seem more or less artificial and forced. Hence
-the attempt here offered must be regarded as entirely provisional. But
-the more deeply we penetrate into the genealogical secrets of this
-obscure domain of inquiry, the more probable appears the idea that the
-vegetable kingdom and the animal kingdom are each of independent origin,
-and that midway between these two great pedigrees a number of other
-independent small groups of organisms have arisen by repeated acts of
-spontaneous generation, which on account of their indifferent neutral
-character, and in consequence of their mixture of animal and vegetable
-properties, may lay claim to the designation of independent Protista.
-
-
-         II.                                             III.
-
-  =Vegetable Kingdom=                             =Animal Kingdom=
-        Plantæ                                        _Animalia_
-  /--------^----------\  /-------------------------------^------------\
-   Flowering Plants                               Vertebrate Animals
-   _Phanerogamia_                                   _Vertebrata_
-         |                                         \-----v-------/
-         |                                               |
-         |                                               |
-         |                           Articulated Animals |
-         |                              _Arthropoda_     |
-         |                              \-----v------/   |
-         |                                    |          |
-         |                                    |          |
-         |                  Star-fishes       |          |  Molluscous Animals
-       Ferns              _Echinoderma_       |          |    _Mollusca_
-    _Filicinæ_            \-----v------/      |          |  \-----v------/
-         |                      |             |          |        |
-         |                      |             |          |        |
-         |                      |             |          |        |
-         |                      |             |          |        |
-      Mosses                   \-------------------v---------------/
-   _Muscinæ_        Lichens                       Worms
-         |         _Lichenes_                    _Vermes_
-         |             |                             |
-         |             |                             |
-         |             |               Animal-trees  |
-         |             |              _Zoophytes_    |
-        ----           Fungi                 |         |
-      _Algæ_        _Fungi_                |         |
-         |             |                   |         |
-         |             |                   |         |
-         \-------v-----/                   \-----v---/
-                            =Neutral=
-  =Primæval Plants=   =Primæval Creatures=  =Primæval Animals=
-      Protophyta          Protista            Protozoa
-     \-----v------/      \-----v------/     \-----v------/
-
-          |||             |||||||||||           |||||
-          |||             |||||||||||           |||||
-          |||             |||||||||||           |||||
-     Vegetable Monera     Neutral Monera      Animal Monera
-           |                 |||||                |
-           |                 |||||                |
-           |                 |||||                |
-          \--------------------------v------------/
-
-                                     |
-                                     |
-                            =Archigonic Monera=
-
-  (Pieces of Protoplasm which have originated by Spontaneous Generation)
-
-             ----------------------------------------------------------------
-
-
-  POLYPHYLETIC PEDIGREE.
-
-         II.                                       I.                                III.
-
-    =Vegetable=                               =Protista=                          =Animal=
-     =Kingdom=                                =Kingdom=                           =Kingdom=
-     Vegetabilia                              Protista                            Animalia
-   \------v------/                                |                              \-----v----/
-          |                                       |                                    |
-          |                                       |                                    |
-          |   /-----------------------------------^--------------------------------\   |
-          |    Slime-moulds,                                                           |
-          |        or                                                                  |
-          |    Mucous Fungi                                   Ray-streamers            |
-          |    _Myxomycetes_                                   _Rhizopoda_             |
-          |   \-----v------/                                 \-----v------/            |
-          |         |                                              |                   |
-          |         |   Flint-cells                                |   Flimmer-balls   |
-          |         |    _Diatomæ_                                 |     _Catallacta_  |
-          |         | \-----v------/                               |    \-----v------/ |
-          |         |       |                                      |          |        |
-          |         |       |                      Whip-swimmers   |          |        |
-          |         |       |                       _Flagellata_   |          |        |
-          |         |       |                      \-----v------/  |          |        |
-          |         |       |                            |         |          |        |
-          |         |       |    Tram-weavers            |         |          |        |
-          |         |       |   _Labyrinthulea_          |         |          |        |
-          |         |       |    \-----v------/          |         |          |        |
-          |         |       |          |                 |         |          |        |
-          |         |       |          |     Amoebæ,     |         |          |    =Primæval=
-  =Primæval Plants= |       |          |       or        |         |          |    =Animals=
-       Protophyta   |       |          |   Protoplasta   |         |          |     Protozoa
-   \------v------/  |       |          | \-----v------/  |         |          |  \-----v------/
-         |||        |       |          |     |||||       |         |          |     |||||||
-         |||        |       |          |     |||||       |         |          |     |||||||
-         |||        |       |          |     |||||       |         |          |     |||||||
-         |||        |       |          |     |||||       |         |          |     |||||||
-     =Vegetable=    |       |          |   =Neutral=     |         |          |     =Animal=
-       =Monera=     |       |          |   =Monera=      |         |          |     =Monera=
-          |         |       |          |       |         |     T   |  T T     |  T     |
-     T    |         |   T   |          |  T    |         |   T |   |  | | T   |  |T    |    T
-     |T   |   T     |  T|   |    T     |  |T   |  T      |   | |   |  |T| |   |  ||T   |  T |T
-     ||T  |   |T    |  ||   |    |     |  ||   |  |T     |   |T|   |  |||T|   |  |||T  |  | ||
-    T|||T |  T||T   |  ||T  |   T|T    |  ||T  |  ||T    |   |||   |  |||||   |  ||||  |  |T||T
-    ||||| |  ||||   |  |||  |   |||    |  |||  |  |||    |   |||   |  |||||   |  ||||  |  |||||
-    ||||| |  ||||   |  |||  |   |||    |  |||  |  |||    |   |||   |  |||||   |  ||||  |  |||||
-    -------------------------------------------------------------------------------------------
-
-  N.B.--The lines marked with a T indicate extinct tribes of Protista,
-  which have arisen independently by repeated acts of Spontaneous Generation.
-
-
-Thus, if we assume one entirely independent trunk for the vegetable
-kingdom, and a second for the animal kingdom, we may set up a number of
-independent stems of Protista, each of which has developed, quite
-independently of other stems and trunks, from a special archigonic form
-of Monera. In order to make this relation more clear, we may imagine the
-whole world of organisms as an immense meadow which is partially
-withered, and upon which two many-branched and mighty trees are
-standing, likewise partially withered. The two great trees represent the
-animal and vegetable kingdoms, their fresh and still green branches the
-living animals and plants; the dead branches with withered leaves
-represent the extinct groups. The withered grass of the meadow
-corresponds to the numerous extinct tribes, and the few stalks, still
-green, to the still living phyla of the kingdom Protista. But the common
-soil of the meadow, from which all have sprung up, is primæval by
-protoplasm.
-
-
-
-
-CHAPTER XVII.
-
-PEDIGREE AND HISTORY OF THE VEGETABLE KINGDOM.
-
-
-  The Natural System of the Vegetable Kingdom.--Division of the
-  Vegetable Kingdom into Six Branches and Eighteen Classes.--The
-  Flowerless Plants (Cryptogamia).--Sub-kingdom of the Thallus
-  Plants.--The Tangles, or Algæ (Primary Algæ, Green Algæ, Brown
-  Algæ, Red Algæ).--The Thread-plants, or Inophytes (Lichens and
-  Fungi).--Sub-kingdom of the Prothallus Plants.--The Mosses, or
-  Muscinæ (Water-mosses, Liverworts, Leaf-mosses,
-  Bog-mosses).--The Ferns, or Filicinæ (Leaf-ferns, Bamboo-ferns,
-  Water-ferns, Scale-ferns).--Sub-kingdom of Flowering Plants
-  (Phanerogamia).--The Gymnosperms, or Plants with Naked Seeds
-  (Palm-ferns = Cycadeæ; Pines = Coniferæ).--The Angiosperms, or
-  Plants with Enclosed Seeds.--Monocotylæ.--Dicotylæ.--Cup-blossoms
-  (Apetalæ).--Star-blossoms (Diapetalæ).--Bell-blossoms
-  (Gamopetalæ).
-
-
-Every attempt that we make to gain a knowledge of the pedigree of any
-small or large group of organisms related by blood must, in the first
-instance, start with the evidence afforded by the existing "_natural
-system_" of this group. For although the natural system of animals and
-plants will never become finally settled, but will always represent a
-merely approximate knowledge of true blood relationship, still it will
-always possess great importance as a hypothetical pedigree. It is true,
-by a "natural system" most zoologists and botanists only endeavour to
-express in a concise way the subjective conceptions which each has
-formed of the objective "_form-relationships_" of organisms. These
-form-relationships, however, as the reader has seen, are in reality the
-necessary result of true _blood relationship_. Consequently, every
-morphologist in promoting our knowledge of the natural system, at the
-same time promotes our knowledge of the pedigree, whether he wishes it
-or not. The more the natural system deserves its name, and the more
-firmly it is established upon the concordance of results obtained from
-the study of comparative anatomy, ontogeny, and palæontology, the more
-surely may we consider it as the approximate expression of the true
-pedigree of the organic world.
-
-In entering upon the task contemplated in this chapter, the genealogy of
-the vegetable kingdom, we shall have, according to this principle, first
-to glance at the _natural system of the vegetable kingdom_ as it is at
-present (with more or less important modifications) adopted by most
-botanists. According to the system generally in vogue, the whole series
-of vegetable forms is divided into two main groups. These main
-divisions, or sub-kingdoms, are the same as were distinguished more than
-a century ago by Charles Linnæus, the founder of systematic natural
-history, and which he called _Cryptogamia_, or secretly-blossoming
-plants, and _Phanerogamia_, or openly-flowering plants. The latter,
-Linnæus, in his artificial system of plants, divided, according to the
-different number, formation, and combination of the anthers, and also
-according to the distribution of the sexual organs, into twenty-three
-different classes, and then added the Cryptogamia to these as the
-twenty-fourth and last class.
-
-The _Cryptogamia_, the secretly-blossoming or flowerless plants, which
-were formerly but little observed, have in consequence of the careful
-investigations of recent times been proved to present such a great
-variety of forms, and such a marked difference in their coarser and
-finer structure, that we must distinguish no less than fourteen
-different classes of them; whereas the number of classes of flowering
-plants, or _Phanerogamia_, may be limited to four. However, these
-_eighteen classes of the vegetable kingdom_ can again be naturally
-grouped in such a manner that we are able to distinguish in all _six
-main divisions_ or _branches_ of the vegetable kingdom. Two of these six
-branches belong to the flowering, and four to the flowerless plants. The
-table on page 82 shows how the eighteen classes are distributed among
-the six branches, and how these again fall under the _sub-kingdoms_ of
-the vegetable kingdom.
-
-The one sub-kingdom of the _Cryptogamia_ may now be naturally divided
-into _two_ divisions, or sub-kingdoms, differing very essentially in
-their internal structure and in their external form, namely, the Thallus
-plants and the Prothallus plants. The group of _Thallus plants_
-comprises the two large branches of Tangles, or Algæ, which live in
-water, and the Thread-plants, or Inophytes (Lichens and Fungi), which
-grow on land, upon stones, bark of trees, upon decaying bodies, etc. The
-group of _Prothallus plants_, on the other hand, comprises the two
-branches of Mosses and Ferns, containing a great variety of forms.
-
-All _Thallus plants, or Thallophytes_, can be directly recognized from
-the fact that the two morphological fundamental organs of all other
-plants, stem and leaves, cannot be distinguished in their structure. The
-complete body of all Algæ and of all Thread-plants is a mass composed of
-simple cells, which is called a _lobe_, or _thallus_. This thallus is
-as yet not differentiated into axial-organs (stem and root) and
-leaf-organs. On this account, as well as through many other
-peculiarities, the Thallophytes contrast strongly with all remaining
-plants--those comprised under the two sub-kingdoms of Prothallus plants
-and Flowering plants--and for this reason the two latter sub-kingdoms
-are frequently classed together under the name of _Stemmed plants_, or
-_Cormophytes_. The following table will explain the relation of these
-three sub-kingdoms to one another according to the two different
-views:--
-
-
-                         { A. Thallus Plants      }  I. Thallus Plants
-                         {    (_Thallophyta_)     }    (_Thallophyta_)
-  I. Flowerless Plants.  {
-   (_Cryptogamia_)       {
-                         { B. Prothallus Plants   }
-                         {    (_Prothallophyta_)  }
-                                                  }  II. Stemmed Plants
-                                                  }   (_Cormophyta_)
-                                                  }
-  II. Flowering Plants   { C. Flowering Plants    }
-    (_Phanerogamia_)     {    (_Phanerogamia_)    }
-
-
-The stemmed plants, or Cormophytes, in the organization of which the
-difference of axial-organs (stem and root) and leaf-organs is already
-developed, form at present, and have, indeed, for a very long period
-formed, the principal portion of the vegetable world. However, this was
-not always the case. In fact, stemmed plants, not only of the flowering
-group, but even of the prothallus group, did not exist at all during
-that immeasurably long space of time which forms the beginning of the
-first great division of the organic history of the earth, under the name
-of the archilithic, or primordial period. The reader will recollect that
-during this period the Laurentian, Cambrian, and Silurian systems of
-strata were deposited, the thickness of which, taken as a whole,
-amounts to about 70,000 feet. Now, as the thickness of all the more
-recent super-incumbent strata, from the Devonian to the deposits of the
-present time, taken together, amounts to only about 60,000 feet, we were
-enabled from this fact alone to draw the conclusion--which is probable
-also for other reasons--that the archilithic, or primordial, period was
-of longer duration than the whole succeeding period down to the present
-time. During the whole of this immeasurable space of time, which
-probably comprises many millions of centuries, vegetable life on our
-earth seems to have been represented exclusively by the sub-kingdom of
-Thallus plants, and, moreover, only by the class of marine Thallus
-plants, that is to say, the Algæ. At least all the petrified remains
-which are positively known to be of the primordial period belong
-exclusively to this class. As all the animal remains of this immense
-period also belong exclusively to animals that lived in water, we come
-to the conclusion that at that time organisms adapted to a life on land
-did not exist at all.
-
-For these reasons the first and most imperfect of the great provinces or
-branches of the vegetable kingdom, the division of the Algæ, or Tangles,
-must be of special interest to us. But, in addition, there is the
-interest which this group offers when viewed by itself. In spite of the
-exceedingly simple composition of their constituent cells, which are but
-little differentiated, the Algæ show an extraordinary variety of
-different forms. To them belong the simplest and most imperfect of all
-forms, as well as very highly developed and peculiar forms. The
-different groups of Algæ are distinguished as much by size of body as by
-the perfection and variety of their outer form. At the lowest stage we
-find such species as the minute Protococcus, several hundred thousands
-of which occupy a space no larger than a pin's head. At the highest
-stage we marvel at the gigantic Macrocysts, which attain a length of
-from 300 to 400 feet, the longest of all forms in the vegetable kingdom.
-It is possible that a large portion of the coal has been formed out of
-Algæ. If not for these reasons, yet the Algæ must excite our special
-attention from the fact that they form the beginning of vegetable life,
-and contain the original forms of all other groups of plants, supposing
-that our monophyletic hypothesis of a common origin for all groups of
-plants is correct. (Compare p. 83.)
-
-SYSTEMATIC VIEW
-
-_Of the Six Branches and Eighteen Classes of the Vegetable Kingdom._
-
-
-  ==========================================================================================
-  _Primary Groups_        |                       |                      |
-  _or Sub-Kingdoms_       | _Branches or Clades_  |    _Classes_         | _Systematic Name_
-    _of the_              |      _of the_         |     _of the_         |     _of the_
-  _Vegetable Kingdom._    | _Vegetable Kingdom._  | _Vegetable Kingdom._ |    _Classes._
-  ------------------------+-----------------------+----------------------+------------------
-
-                          {                       {  1. Primæval algæ     1. _Archephyceæ_
-                          {                       {                          (Protophyta)
-                          {                       {
-                          {       I.              {  2. Green algæ        2. _Chlorophyceæ_
-           A.             {    Tangles            {                           (Chloroalgæ)
-    =Thallus Plants=      {     _Algæ_            {
-      Thallophyta         {                       {  3. Brown algæ        3. _Phæophyceæ_
-                          {                       {                          (Fucoideæ)
-                          {                       {
-                          {                       {  4. Red algæ          4. _Rhodophyceæ_
-                          {                       {                          (Florideæ)
-
-                          {      II.              {  5. Lichens           5. _Lichenes_
-                          {  Thread-plants        {
-                          {   _Inophyta_          {  6. Fungi             6. _Fungi_
-                          {
-                          {                       {  7. Tangle-mosses     7. _Charobrya_
-                          {                       {                           (Characeæ)
-                          {                       {
-                          {      III.             {  8. Liverworts        8. _Thallobrya_
-                          {     Mosses            {                           (Hepaticæ)
-                          {    _Muscinæ_          {
-                          {                       {  9. Frondose-mosses   9. _Phyllobrya_
-           B.             {                       {                           (Frondosæ)
-      =Prothallus=        {                       {
-        =Plants=          {                       { 10. Turf-mosses       10. _Sphagnobrya_
-     Prothallophyta       {                                                    (Sphagnaceæ)
-                          {
-                          {                       { 11. Shaft-ferns       11. _Calamariæ_
-                          {                       {                          (Calamophyta)
-                          {      IV.              {
-                          {     Ferns             { 12. Frondose-ferns    12. _Filices_
-                          {   _Felicinæ_          {                           (Pterideæ)
-                          {                       {
-                          {                       { 13. Aquatic ferns     13. _Rhizocarpeæ_
-                          {                       {                           (Hydropterides)
-                          {                       {
-                          {                       { 14. Scale-ferns       14. _Selagineæ_
-                          {                       {                           (Lepidophyta)
-
-                          {       V.              {
-                          {   Plants with         { 15. Palm-ferns        15. _Cycadeæ_
-           C.             {   Naked Seeds         {
-   =Flowering Plants=     {  _Gymnosperma_        { 16. Pines             16. _Coniferæ_
-      Phanerogamia        {
-                          {      VI.              { 17. Plants with       17. _Monocotylæ_
-                          {  Plants with          {    one seed lobe
-                          { Enclosed Seeds        {
-                          {  _Angiosperma_        { 18. Plants with       18. _Dicotylæ_
-                          {                       {    two seed lobes
-
-             ----------------------------------------------------------------
-
-
-              _Gamopetalæ_
-         (Flowers with corolla)
-                    |
-            _Dialypetalæ_
-         (Star-shaped flowers)
-                    |
-             _Monochlamydeæ_                    MONOCOTYLEDONÆ
-          (Flowers with calyx)             (One seed-lobed plants)
-                    |                                  |
-              DICOTYLEDONÆ                             |
-         (Two seed-lobed plants)                       |
-                    |                                  |
-                    \--------------------v-------------/
-              CONIFERÆ             +Angiospermæ+
-  CYCADEÆ     (Pines)         (Plants with enclosed seeds)
-  (Palm-ferns)   |       GNETACEÆ        |
-     |           |           |           |
-     \-----------v-----------------------/
-           +Gymnospermæ+
-    (Plants with naked seeds)   _Phanerogamæ_
-                 |            (Flowering plants) _Pterideæ_
-  _Selagineæ_    | _Rhizocarpeæ_      |       (Frondose-ferns)
-  (Scaled-ferns) |(Water-ferns)       |              |    _Calamariæ_
-      |          |      |             |              |   (Shaft-ferns)
-      |          |      |             |              |         |
-      \-------------------------------v------------------------/
-                                  +Filicinæ+
-    _Frondosæ_     _Sphagnaceæ_    (Ferns)
-   (Leaf-mosses)  (Turf-mosses)       |
-        |                |            |                      CHARACEÆ
-        \----------------v------------/                   (Tangle-mosses)
-                         |                                       |
-               _Hepaticæ_ (Liverworts)                           |
-                         |                                       |
-                         \------------------v--------------------/
-                                        +Muscinæ+ (Mosses)
-                     _Fucoideæ_             |
-  _Florideæ_        (Brown Algæ)            |                _Lichenes_
-  (Red Algæ)              |           _Chlorophyceæ_         (Lichens)
-       |                  |            (Green Algæ)              |
-       |                  |                 |                    |
-       \------------------v-----------------/            +Fungi Inophyta+
-                   +Algæ+ (Tangles)                        (Thread-plants)
-                          |                                      |
-                          \-------v------------------------------/
-                              _Protophyta_
-                           (Primæval Plants)
-                                  |
-                          _Vegetable Monera_
-
-Most people living inland can form but a very imperfect idea of this
-exceedingly interesting branch of the vegetable kingdom, because they
-know only its proportionately small and simple representatives living in
-fresh water. The slimy green aquatic filaments and flakes of our pools
-and ditches and springs, the light green slimy coverings of all kinds of
-wood which have for any length of time been in contact with water, the
-yellowish green, frothy, and oozy growths of our village ponds, the
-green filaments resembling tufts of hair which occur everywhere in fresh
-water, stagnant and flowing, are for the most part composed of different
-species of Algæ. Only those who have visited the sea-shore, and wondered
-at the immense masses of cast-up seaweed, and who, from the rocky coast
-of the Mediterranean, have seen through the clear blue waters the
-beautifully-formed and highly-coloured vegetation of Algæ at the bottom,
-know how to estimate the importance of the class of Algæ. And yet, even
-these marine Algæ-forests of European shores, so rich in forms, give
-only a faint idea of the colossal forests of Sargasso in the Atlantic
-ocean, those immense banks of Algæ, covering a space of about 40,000
-square miles--the same which made Columbus, on his voyage of discovery,
-believe that a continent was near. Similar but far more extensive
-forests of Algæ grew in the primæval ocean, probably in dense masses,
-and what countless generations of these archilithic Algæ have died out
-one after another is attested, among other facts, by the vast thickness
-of Silurian alum schists in Sweden, the peculiar composition of which
-proceeds from those masses of submarine Algæ. According to the recently
-expressed opinion of Frederick Mohr, a geologist of Bonn, even the
-greater part of our coal seams have arisen out of the accumulated dead
-bodies of the Algæ forests of the ocean.
-
-Within the branch of the Algæ we distinguish four different classes,
-each of which is again divided into several orders and families. These
-again contain a large number of different genera and species. We
-designate these four classes as Primæval Algæ, or Archephyceæ, Green
-Algæ, or Chlorophyceæ, Brown Algæ, or Phæophyceæ, and Red Algæ, or
-Rhodophyceæ.
-
-The first class of Algæ, the _Primæval_ Algæ (Archephyceæ), might also
-be called _primæval plants_, because they contain the simplest and most
-imperfect of all plants, and, among them, those most ancient of all
-vegetable organisms out of which all other plants have originated. To
-them therefore belong those most ancient of all vegetable Monera which
-arose by spontaneous generation in the beginning of the Laurentian
-period. Further, we have to reckon among them all those vegetable forms
-of the simplest organization which first developed out of the Monera in
-the Laurentian period, and which possessed the form of a single
-plastid. At first the entire body of one of these small primary plants
-consisted only of a most simple cytod (a plastid without kernel), and
-afterwards attained the higher form of a simple cell, by the separation
-of a kernel in the plasma. (Compare above, vol. i. p. 345.) Even at the
-present day there exist various most simple forms of Algæ which have
-deviated but little from the original primary plants. Among them are the
-Algæ of the families Codiolaceæ, Protococcaceæ, Desmidiaceæ,
-Palmellaceæ, Hydrodictyeæ, and several others. The remarkable group of
-Phycochromaceæ (Chroococcaceæ and Oscillarineæ) might also be comprised
-among them, unless we prefer to consider them as an independent tribe of
-the kingdom Protista.
-
-The monoplastic Protophyta--that is, those primary Algæ formed by a
-single plastid--are of the greatest interest, because the vegetable
-organism in this case completes its whole course of life as a perfectly
-simple "individual of the first order," either as a cytod without
-kernel, or as a cell containing a kernel.
-
-Among the primary plants consisting of a single cytod are the
-exceedingly remarkable Siphoneæ, which are of considerable size, and
-strangely "mimic" the forms of higher plants. Many of the Siphoneæ
-attain a size of several feet, and resemble an elegant moss (Bryopsis),
-or in some cases a perfect flowering plant with stalks, roots, and
-leaves (Caulerpa) (Fig. 17). Yet the whole of this large body,
-externally so variously differentiated, consists internally of an
-entirely simple sack, possessing the negative characters of a simple
-cytod.
-
-[Illustration: FIG. 17.--Caulerpa denticulata, a monoplastic Siphonean
-_of the natural size_. The entire branching primary plant, which appears
-to consist of a creeping stalk with fibrous roots and indented leaves,
-is in reality only _a single plastid_, and moreover a cytod (without a
-kernel), not even attaining the grade of a cell with nucleus.]
-
-These curious Siphoneæ, Vaucheriæ, and Caulerpæ show us to how great a
-degree of elaboration a single cytod, although a most simple individual
-of the first order, can develop by continuous adaptation to the
-relations of the outer world. Even the _single-celled primary
-plants_--which are distinguished from the monocytods by possessing a
-kernel--develop into a great variety of exquisite forms by adaptation;
-this is the case especially with the beautiful _Desmidiaceæ_, of which
-a species of Euastrum is represented in Fig. 18 as a specimen.
-
-[Illustration: FIG. 18.--Euastrum rota, a single-celled Desmid, much
-enlarged. The whole of the star-shaped body of this primæval plant has
-the formal value of a simple cell. In its centre lies the kernel, and
-within this the kernel corpuscle, or speck.]
-
-It is very probable that similar primæval plants, the soft body of
-which, however, was not capable of being preserved in a fossil state, at
-one time peopled the Laurentian primæval sea in great masses and
-varieties, and in a great abundance of forms, without, however, going
-beyond the stage of individuality of a simple plastid.
-
-The group of _Green Tangles_ (Chlorophyceæ), or _Green Algæ_
-(Cloroalgæ), are the second class, and the most closely allied to the
-primæval group. Like the majority of the Archephyceæ, all the
-Chlorophyceæ are coloured green, and by the same colouring matter--the
-substance called leaf-green, or chlorophyll--which colours the leaves of
-all the higher plants.
-
-To this class belong, besides a great number of low marine Algæ, most of
-the Algæ of fresh water, the common water hair-weeds, or Confervæ, the
-green slime-balls, or Gloeosphæræ, the bright green water-lettuce, or
-Ulva, which resembles a very thin and long lettuce leaf, and also
-numerous small microscopic algæ, dense masses of which form a light
-green shiny covering to all sorts of objects lying in water--wood,
-stones, etc.
-
-These forms, however, rise above the simple primary Algæ in the
-composition and differentiation of their body. As the green Algæ, like
-the primæval Algæ, mostly possess a very soft body, they are but rarely
-capable of being petrified. However, it can scarcely be doubted that
-this class of Algæ--which was the first to develop out of the preceding
-one--most extensively and variously peopled the fresh and salt waters of
-the earth in early times.
-
-In the third class, that of the _Brown Tangles_ (Phæophyceæ), or _Black
-Algæ_ (Fucoideæ), the _branch_ of the Algæ attains its highest stage of
-development, at least in regard to size and body. The characteristic
-colour of the Fucoid is more or less dark brown, sometimes tending more
-to an olive green or yellowish green, sometimes more to a brownish red
-or black colour.
-
-Among these are the largest of all Algæ, which are at the same time the
-longest of all plants, namely, the colossal giant Algæ, amongst which
-the Macrocystis pyrifera, on the coast of California, attains a length
-of 400 feet. Also, among our indigenous Algæ, the largest forms belong
-to this group. Especially I may mention here the stately sugar-tangle
-(Laminaria), whose slimy, olive green thallus-body, resembling gigantic
-leaves of from 10 to 15 feet in length, and from a half to one foot in
-breadth, are thrown up in great masses on the coasts of the North and
-Baltic seas.
-
-To this class belongs also the bladder-wrack (Fucus vesiculosus) common
-in our seas, whose fork-shaped, deeply-cut leaves are kept floating on
-the water by numerous air bladders (as is the case, too, with many other
-brown Algæ). The freely floating Sargasso Alga (Sargasso bacciferum),
-which forms the meadows or forests of the Sargasso Sea, also belongs to
-this class.
-
-Although each individual of these large alga-trees is composed of many
-millions of cells, yet at the beginning of its existence it consists,
-like all higher plants, of a single cell--a simple egg. This egg--for
-example, in the case of our common bladder-wrack--is a naked, uncovered
-cell, and as such is so like the naked egg-cells of lower marine
-animals--for example, those of the Medusæ--that they might easily be
-mistaken one for another (Fig. 19).
-
-[Illustration: FIG. 19.--The egg of the common bladder-wrack (Fucus
-vesiculosus), a simple naked cell, much enlarged. In the centre of the
-naked globule of protoplasm the bright kernel is visible.]
-
-It was probably the Fucoideæ, or Brown Algæ, which during the primordial
-period, to a great extent constituted the characteristic alga-forests of
-that immense space of time. Their petrified remains, especially those
-of the Silurian period, which have been preserved, can, it is true,
-give us but a faint idea of them, because the material of these Algæ,
-like that of most others, is ill-suited for preservation in a fossil
-state. As has already been remarked, a large portion of coal is perhaps
-composed of them.
-
-Less important is the fourth class of Algæ, that of the _Rose-coloured
-Algæ_ (Rhodophyceæ), or _Red Sea-weeds_ (Florideæ). This class, it is
-true, presents a great number of different forms; but most of them are
-of much smaller size than the Brown Algæ. Although they are inferior to
-the latter in perfection and differentiation, they far surpass them in
-some other respects. To them belong the most beautiful and elegant of
-all Algæ, which on account of the fine plumose division of their
-leaf-like bodies, and also on account of their pure and delicate red
-colour, are among the most charming of plants. The characteristic red
-colour sometimes appears as a deep purple, sometimes as a glowing
-scarlet, sometimes as a delicate rose tint, and may verge into violet
-and bluish purple, or on the other hand into brown and green tints of
-marvellous splendour. Whoever has visited one of our sea-coast watering
-places, must have admired the lovely forms of the Florideæ, which are
-frequently dried on white paper and offered for sale.
-
-Most of the Red Algæ are so delicate, that they are quite incapable of
-being petrified; this is the case with the splendid Ptilotes, Plocamia,
-Delesseria, etc. However, there are individual forms, like the Chondria
-and Sphærococca, which possess a harder thallus, often almost as hard as
-cartilage, and of these fossil remains have been preserved--principally
-in the Silurian, Devonian, and Carboniferous strata, and later in the
-oolites. It is probable that this class also had an important share in
-the composition of the archilithic Algæ flora.
-
-If we now again take into consideration the flora of the primordial
-period, which was exclusively formed by the group of Algæ, we can see
-that it is not improbable that its four subordinate classes had a share
-in the composition of those submarine forests of the primæval oceans,
-similar to that which the four types of vegetation--trees with trunks,
-flowering shrubs, grass, and tender leaf-ferns and mosses--at present
-take in the composition of our recent land forests.
-
-We may suppose that the submarine tree forests of the primordial period
-were formed by the huge Brown Algæ, or Fucoideæ. The many-coloured
-flowers at the foot of these gigantic trees were represented by the gay
-Red Algæ, or Florideæ. The green grass between was formed by the
-hair-like bunches of Green Algæ, or Chloroalgæ. Finally, the tender
-foliage of ferns and mosses, which at present cover the ground of our
-forests, fill the crevices left by other plants, and even settle on the
-trunks of the trees, at that time probably had representatives in the
-moss and fern-like Siphoneæ, in the Caulerpa and Bryopsis, from among
-the class of the primary Algæ, Protophyta, or Archephyceæ.
-
-With regard to the relationships of the different classes of Algæ to one
-another and to other plants, it is exceedingly probable that the Primary
-Algæ, or Archephyceæ, as already remarked, form the common root of the
-pedigree, not merely for the different classes of Algæ, but for the
-whole vegetable kingdom. On this account they may with justice be
-designated as primæval plants, or Protophyta.
-
-Out of the naked vegetable Monera, in the beginning of the Laurentian
-period, enclosed cytods were probably the first to arise (vol. i. p.
-345), by the naked, structureless, albuminous substance of the Monera
-becoming condensed in the form of a pellicle on the surface, or by
-secreting a membrane. At a later period, out of these enclosed cytods
-genuine vegetable cells probably arose, as a kernel or nucleus separated
-itself in the interior from the surrounding cell-substance or plasma.
-
-The three classes of Green Algæ, Brown Algæ, and Red Algæ, are perhaps
-three distinct classes, which have arisen independently of one another
-out of the common radical group of Primæval Algæ, and then developed
-themselves further (each according to its kind), and have variously
-branched off into orders and families. The Brown and Red Algæ possess no
-close blood relationship to the other classes of the vegetable kingdom.
-These latter have most probably arisen out of the Primæval Algæ, either
-directly or by the intermediate step of the Green Algæ.
-
-It is probable that Mosses (out of which, at a later time, Ferns
-developed) proceeded from a group of Green Algæ, and that Fungi and
-Lichens proceeded from a group of Primæval Algæ. The Phanerogamia
-developed at a much later period out of Ferns.
-
-As a second class of the Vegetable Kingdom we have above mentioned the
-_Thread-plants_ (Inophyta). We understood by this term the two closely
-related classes of _Lichens_ and _Fungi_. It is possible that these
-Thallus plants have not arisen out of the Primæval Algæ, but out of one
-or more Monera, which, independently of the latter, arose by spontaneous
-generation. It appears conceivable that many of the lowest Fungi, as for
-example, many ferment-causing fungi (forms of Micrococcus, etc.), owe
-their origin to a number of different _archigonic_ Monera (that is,
-Monera originating by spontaneous generation).
-
-In any case the Thread-plants cannot be considered as the progenitors of
-any of the higher vegetable classes. Lichens, as well as fungi, are
-distinct from the higher plants in the composition of their soft bodies,
-consisting as it does of a dense felt-work of very long, variously
-interwoven, and peculiar threads or chains of cells--the so-called
-_hyphæ_, on which account we distinguish them as a province under the
-name Thread-plants. From their peculiar nature they could not leave any
-important fossil remains, and consequently we can form only a very vague
-guess at their palæontological development.
-
-The first class of Thread-plants, the _Fungi_, exhibit a very close
-relationship to the lowest Algæ; the Algo-fungi, or Phycomycetes (the
-Saprolegniæ and Peronosporæ) in reality only differ from the
-bladder-wracks and Siphoneæ (the Vaucheria and Caulerpa) mentioned
-previously by the want of leaf-green, or chlorophyll. But, on the other
-hand, all genuine Fungi have so many peculiarities, and deviate so much
-from other plants, especially in their mode of taking food, that they
-might be considered as an entirely distinct province of the vegetable
-kingdom.
-
-Other plants live mostly upon inorganic food, upon simple combinations
-which they render more complicated. They produce protoplasm by the
-combination of water, carbonic acid, and ammonia. They take in carbonic
-acid and give out oxygen. But the Fungi, like animals, live upon organic
-food, consisting of complicated combinations of carbon, which they
-receive from other organisms and assimilate. They inhale oxygen and
-give out carbonic acid like animals. They also never form leaf-green, or
-chlorophyll, which is so characteristic of most other plants. In like
-manner they never produce starch. Hence many eminent botanists have
-repeatedly proposed to remove the Fungi completely out of the vegetable
-kingdom, and to regard them as a special and third kingdom, between that
-of animals and plants. By this means our kingdom of Protista would be
-considerably increased. The Fungi in this case would, in the first
-place, be allied to the so-called "slime moulds," or Myxomycetes (which,
-however, never form any hyphæ). But as many Fungi propagate in a sexual
-manner, and as most botanists, according to the prevalent opinion, look
-upon Fungi as genuine plants, we shall here leave them in the vegetable
-kingdom, and connect them with lichens, to which they are at all events
-most nearly related.
-
-The phyletic origin of Fungi will probably long remain obscure. The
-close relationship already hinted at between the Phycomycetes and
-Siphoneæ (especially between the Saprolegniæ and Vaucheriæ) suggests to
-us that they are derived from the latter. Fungi would then have to be
-considered as Algæ, which by adaptation to a parasitical life have
-become very peculiarly transformed. Many facts, however, support the
-supposition that the lowest fungi have originated independently from
-archigonic Monera.
-
-The second class of Inophyta, the _Lichens_ (Lichenes), are very
-remarkable in relation to phylogeny; for the surprising discoveries of
-late years have taught us that every Lichen is really composed of two
-distinct plants--of a low form of Alga (Nostochaceæ, Chroococcaceæ), and
-of a parasitic form of Fungus (Ascomycetes), which lives as a parasite
-upon the former, and upon the nutritive substances prepared by it. The
-green cells, containing chlorophyll (gonidia), which are found in every
-lichen, belong to the Alga. But the colourless threads (hyphæ) which,
-densely interwoven, form the principal mass of the body of Lichens,
-belong to the parasitic Fungus. But in all cases the two forms of
-plants--Fungus and Alga--which are always considered as members of two
-quite distinct provinces of the vegetable kingdom, are so firmly united,
-and so thoroughly interwoven, that nearly every one looks upon a Lichen
-as a single organism.
-
-Most Lichens form small, more or less formless or irregularly indented,
-crust-like coverings to stones, bark of trees, etc. Their colour varies
-through all possible tints, from the purest white to yellow, red, green,
-brown, and the deepest black.
-
-Many lichens are important in the economy of nature from the fact that
-they can settle in the driest and most barren localities, especially on
-naked rocks upon which no other plant can live. The hard black lava,
-which covers many square miles of ground in volcanic regions, and which
-for centuries frequently presents the most determined opposition to the
-life of every kind of vegetation, is always first occupied by Lichens.
-It is the white or grey Lichens (Stereocaulon) which, in the most
-desolate and barren fields of lava, always begin to prepare the naked
-rocky ground for cultivation, and conquer it for subsequent higher
-vegetation. Their decaying bodies form the first mould in which mosses,
-ferns, and flowering plants can afterwards take firm root. Hardy Lichens
-are also less affected by the severity of climate than any other plants.
-Hence the naked rocks, even in the highest mountains--for the most part
-covered by eternal snow, on which no plant could thrive--are encrusted
-by the dry bodies of Lichens.
-
-Leaving now the Fungi, Lichens, and Algæ, which are comprised under the
-name of Thallus plants, we enter upon the second sub-kingdom of the
-vegetable kingdom, that of the _Prothallus plants_ (Prothallophyta),
-which by some botanists are called phyllogonic Cryptogamia (in
-contradistinction to the Thallus plants, or thallogonic Cryptogamia).
-This sub-kingdom comprises the two provinces of _Mosses_ and _Ferns_.
-
-Here we meet with (except in a few of the lowest forms) the separation
-of the vegetable body into two different fundamental organs,
-axial-organs (stem and root) and leaves (or lateral organs). In this the
-Prothallus plants resemble the Flowering plants, and hence the two
-groups have recently often been classed together as stemmed plants, or
-Cormophytes.
-
-But, on the other hand, Mosses and Ferns resemble the Thallus plants, in
-the absence of the development of flowers and seeds, and even Linnæus
-classed them with these, as Cryptogamia, in contradistinction to the
-plants forming seeds; that is, flowering plants (Anthophyta or
-Phanerogamia).
-
-Under the name of "Prothallus plants" we combine the closely-related
-Mosses and Ferns, because both exhibit a peculiar and characteristic
-"alternation of generation" in the course of their individual
-development. For every species exhibits two different generations, of
-which the one is usually called the _Prothallium_, or _Fore-growth_, the
-other is spoken of as the _Cormus_, or actual _Stem_ of the moss or
-fern.
-
-The first and original generation, the Fore-growth, or Prothallus, also
-called Protonema, still remains in that lower stage of elaboration
-manifested throughout life by all Thallus plants; that is to say, stem
-and leaf-organs have as yet not differentiated, and the entire cell-mass
-of the Fore-growth corresponds to a simple thallus. The second and more
-perfect generation of mosses and ferns--the Stem, or Cormus--develops a
-much more highly elaborate body, which has differentiated into stalk and
-leaf (as in the case of flowering plants), except in the lowest mosses,
-where this generation also remains in the lower stage of the thallus.
-
-With the exception of these latter forms the first generation of Mosses
-and Ferns (the thallus-shaped Fore-growth) always produces a second
-generation with stem and leaves; the latter in its turn produces the
-thallus of the first generation, and so on. Thus, in this case, as in
-the ordinary cases of alternation of generation in animals, the first
-generation is like the third, fifth, etc., the second like the fourth,
-sixth, etc. (Compare vol. i. p. 206.)
-
-Of the two main classes of Prothallus plants, the Mosses in general are
-at a much lower stage of development than the Ferns, and their lowest
-forms (especially in an anatomical respect) form the transition from the
-Thallus plants through the Algæ to Ferns. The genealogical connection of
-Mosses and Ferns which is indicated by this fact can, however, be
-inferred only from the case of the most imperfect forms of the two
-classes; for the more perfect and higher groups of mosses and ferns do
-not stand in any close relation to one another, and develop in
-completely opposite directions. In any case Mosses have arisen directly
-out of Thallus plants, and probably out of Green Algæ.
-
-Ferns, on the other hand, are probably derived from extinct unknown
-Mosses, which were very nearly related to the lowest liverworts of the
-present day. In the history of creation, Ferns are of greater importance
-than Mosses.
-
-The branch of _Mosses_ (Muscinæ, also called Musci, or Bryophyta)
-contains the lower and more imperfect plants of the group of
-Prothallophytes, which as yet do not possess vessels. Their bodies are
-mostly so tender and perishable that they are very ill-suited for being
-preserved in a recognizable state as fossils. Hence the fossil remains
-of all classes of Mosses are rare and insignificant. It is probable that
-Mosses developed in very early times out of the Thallus plants, or, to
-be more precise, out of the Green Algæ. It is probable that in the
-primordial period there existed aquatic forms of transition from the
-latter to Mosses, and in the primary period to those living on land. The
-Mosses of the present day--out of the gradually differentiating
-development of which comparative anatomy may draw some inferences as to
-their genealogy--are divided into two different classes, namely: (1)
-Liverworts; (2) Leafy Mosses.
-
-The first and oldest class of Mosses, which is directly allied to the
-Green Algæ, or Confervæ, is formed by the _Liverworts_ (Hepaticæ, or
-Thallobrya). The mosses belonging to them are, for the most part, small
-and insignificant in form, and are little known. Their lowest forms
-still possess, in both generations, a simple thallus like the Thallus
-plants; as for example, the Ricciæ and Marchantiaceæ. But the more
-highly developed liverworts, the Jungermanniaceæ and those akin to them,
-gradually commence to differentiate stem and leaf, and their most
-highly-developed forms are closely allied to leaf-mosses. By this
-transitional series the liverworts show their direct derivation from
-the Thallophytes, and more especially from the Green Algæ.
-
-The Mosses, which are generally the only ones known to the
-uninitiated--and which, in fact, form the principal portion of the whole
-branch--belong to the second class, or _Leafy Mosses_ (Musci frondosi,
-called Musci in a narrow sense, also Phyllobrya). Among them are most of
-those pretty little plants which, united in dense groups, form the
-bright glossy carpet of moss in our woods, or which, in company with
-liverworts and lichens, cover the bark of trees. As reservoirs,
-carefully storing up moisture, they are of the greatest importance in
-the economy of nature. Wherever man mercilessly cuts down and destroys
-forests, there, as a consequence, disappear the leafy mosses which
-covered the bark of the trees, or, protected by their shade, clothed the
-ground, and filled the spaces between the larger plants. Together with
-the leafy mosses disappear the useful reservoirs which stored up rain
-and dew for times of drought. Thus arises a disastrous dryness of the
-ground, which prevents the growth of any rich vegetation. In the greater
-part of Southern Europe--in Greece, Italy, Sicily, and Spain--mosses
-have been destroyed by the inconsiderate extirpation of forests, and the
-ground has thereby been robbed of its most useful stores of moisture;
-once flourishing and rich tracts of land have been changed into dry and
-barren wastes. Unfortunately in Germany, also, this rude barbarism is
-beginning to prevail more and more. It is probable that the small
-frondose mosses have played this exceedingly important part in nature
-for a very long time, possibly from the beginning of the primary period.
-But as their tender bodies are as little suited as those of all other
-mosses for being preserved in a fossil state, palæontology can give us
-no information about this.
-
-We learn from the science of petrifactions much more than we do in the
-case of Mosses of the importance which the second branch of Prothallus
-plants--that is, Ferns--have had in the history of the vegetable world.
-Ferns, or more strictly speaking, the "plants of the fern tribe"
-(Filicineæ, or Pterideæ, also called Pteridophyta, or Vascular
-Cryptogams), formed during an extremely long period, namely, during the
-whole primary or palæolithic period, the principal portion of the
-vegetable world, so that we may without hesitation call it the _era of
-Fern Forests_. From the beginning of the Devonian period, in which
-organisms living on land appeared for the first time, namely, during the
-deposits of the Devonian, Carboniferous, and Permian strata, plants like
-Ferns predominated so much over all others, that we are justified in
-giving this name to that period. In the stratifications just mentioned,
-but above all, in the immense layers of coal of the Carboniferous or
-coal period, we find such numerous and occasionally well preserved
-remains of Ferns, that we can form a tolerable vivid picture of the very
-peculiar land flora of the palæolithic period. In the year 1855 the
-total number of the then known palæolithic species of plants amounted to
-about a thousand, and among these there were no less than 872 Ferns.
-Among the remaining 128 species were 77 Gymnosperms (pines and
-palm-ferns), 40 Thallus plants (mostly Algæ), and about 20 not
-accurately definable Cormophyta (stem-plants).
-
-As already remarked, Ferns probably developed out of the lower
-liverworts in the beginning of the primary period. In their
-organization Ferns rise considerably above Mosses, and in their more
-highly developed forms even approach the flowering plants. In Mosses, as
-in Thallus plants, the entire body is composed of almost equi-formal
-cells, little if at all differentiated; but in the tissues of Ferns we
-find those peculiarly differentiated strings of cells which are called
-the vessels of plants, and which are universally met with in flowering
-plants. Hence Ferns are sometimes united as "vascular Cryptogams" with
-Phanerogams, and the group so formed is contrasted as that of the
-"vascular plants" with "cellular plants,"--that is, with "cellular
-cryptogams" (Mosses and Thallus plants). This very important process in
-the organization of plants--the formation of vessels--first occurred,
-therefore, in the Devonian period, consequently in the beginning of the
-second and smaller half of the organic history of the earth.
-
-The branch of Ferns, or Filicinæ, is divided into five distinct classes:
-(1) Frondose Ferns, or Pteridæ; (2) Reed Ferns, or Calamariæ; (3)
-Aquatic Ferns, or Rhizocarpeæ; (4) Snakes Tongues, or Ophioglossæ; and
-(5) Scale Ferns, or Lepidophyta. By far the most important of these five
-classes, and also the richest in forms, were first the Frondose Ferns,
-and then the Scale-ferns, which formed the principal portion of the
-palæolithic forests. The Reed Ferns, on the other hand, had at that time
-already somewhat diminished in number; and of the Aquatic Ferns, we do
-not even know with certainty whether they then existed. It is difficult
-for us to form any idea of the very peculiar character of those gloomy
-palæolithic fern forests, in which the whole of the gay abundance of
-flowers of our present flora was entirely wanting, and which were not
-enlivened by any birds. Of the flowering plants there then existed only
-the two lowest classes, the pines and palm ferns, with naked seeds,
-whose simple and insignificant blossoms scarcely deserve the name of
-flowers.
-
-The phylogeny of Ferns, and of the Gymnosperms which have developed out
-of them, has been made especially clear by the excellent investigations
-which Edward Strasburger published in 1872, on "The Coniferæ and
-Gnetaceæ," as also "On Azolla." This thoughtful naturalist and Charles
-Martins, of Montpellier, are among the few botanists who have thoroughly
-understood the fundamental value of the Theory of Descent, and the
-mechanical-causal connection between ontogeny and phylogeny. The
-majority of botanists do not even yet know the important difference
-between homology and analogy, between the morphological and
-physiological comparison of parts--which has long since been recognized
-in zoology--but Strasburger has employed this distinction and the
-principle of evolution in his "Comparative Anatomy of the Gymnosperms,"
-in order to sketch the outlines of the blood relationship of this
-important group of plants.
-
-The class among Ferns which has developed most directly out of the
-Liverworts is the class of real Ferns, in the narrow sense of the word,
-the _Frondose Ferns_ (Filices, or Phyllopterides, also called Pteridæ).
-In the present flora of the temperate zones this class forms only a
-subordinate part, for it is in most cases represented only by low forms
-without trunks. But in the torrid zones, especially in the moist,
-steaming forests of tropical regions, this class presents us with the
-lofty palm-like _fern trees_. These beautiful tree-ferns of the present
-day, which form the chief ornament of our hot-houses, can however give
-us but a faint idea of the stately and splendid frondose ferns of the
-primary period, whose mighty trunks, densely crowded together, then
-formed entire forests. These trunks, accumulated in super-incumbent
-masses, are found in the coal seams of the Carboniferous period, and
-between them, in an excellent state of preservation, are found the
-impressions of the elegant fan-shaped leaves, crowning the top of the
-trunk in an umbrella-like bush. The varied outlines and the
-feather-like forms of these fronds, the elegant shape of the branching
-veins or bunches of vessels in their tender foliage, can still be as
-distinctly recognized in the impressions of the palæolithic fronds as in
-the fronds of ferns of the present day. In many cases even the clusters
-of fruit, which are distributed on the lower surface of the fronds, are
-distinctly preserved. After the Carboniferous period, the predominance
-of frondose ferns diminished, and towards the end of the secondary
-period they played almost as subordinate a part as they do at the
-present time.
-
-The Calamariæ, Ophioglossæ, and Rhizocarpeæ seem to have developed as
-three diverging branches out of the Frondose Ferns, or Pteridæ. The
-Calamariæ, or Calamophyta, have remained at the lowest level among these
-three classes. The Calamariæ comprise three different orders, of which
-only one now exists, namely, the Horse-tails (Equisetaceæ). The two
-other orders, the Giant Reeds (Calamiteæ), and the Star-leaf Reeds
-(Asterophylliteæ), are long since extinct. All Calamariæ are
-characterized by a hollow and jointed stalk, stem, or trunk, upon which
-the branches and leaves (in cases where they exist) are set so as to
-encircle the jointed stem in whorls. The hollow joints of the stalk are
-separated from one another by partition walls. In Horse-tails and
-Calamiteæ the surface is traversed by longitudinal ribs running
-parallel, as in the case of a fluted column, and the outer skin contains
-so much silicious earth in the living forms, that it is used for
-cleansing and polishing. In the Asterophylliteæ, the star-shaped whorls
-of leaves were more strongly developed than in the two other orders.
-There exist, at present, of the Calamariæ only the insignificant
-Horse-tails (Equisetum), which grow in marshes and on moors; but during
-the whole of the primary and secondary periods they were represented by
-great trees of the genus Equisetites. There existed, at the same time,
-the closely related order of the Giant Reeds (Calamites), whose strong
-trunks grew to a height of about fifty feet. The order of the
-Asterophyllites, on the other hand, contained smaller and prettier
-plants, of a very peculiar form, and belongs exclusively to the primary
-period.
-
-Among all Ferns, the history of the third class, that of the _Root_, or
-_Aquatic Ferns_ (Rhizocarpeæ, or Hydropteridæ), is least known to us. In
-their structure these ferns, which live in fresh water, are on the one
-hand allied to the frond ferns, and on the other to the scaly ferns, but
-they are more closely related to the latter. Among them are the but
-little known moss ferns (Salvinia), clover ferns (Marsilea), and pill
-ferns (Pilularia) of our fresh waters; further, the large Azolla which
-floats in tropical ponds. Most of the aquatic ferns are of a delicate
-nature, and hence ill-suited for being petrified. This is probably the
-reason of their fossil remains being so scarce, and of the oldest of
-those known to us having been found in the Jura system. It is probable,
-however, that the class is much older, and that it was already
-developed during the palæolithic period out of other ferns by adaptation
-to an aquatic life.
-
-The fourth class of ferns is formed by the _Tongue Ferns_ (Ophioglossæ,
-or Glossopterides). These ferns, to which belongs the Botrychium, as
-well as the Ophioglossum (adder's-tongue) of our native genera, were
-formerly considered as forming but a small sub-division of the frondose
-ferns. But they deserve to form a special class, because they represent
-important transitional forms from the Pterideæ and Lepidophytes towards
-higher plants, and must be regarded as among the direct progenitors of
-the flowering plants.
-
-The fifth and last class is formed by the _Scale Ferns_ (Lepidophytes,
-or Selagines). In the same way as the Ophioglossæ arose out of the
-frondose forms, the scale ferns arose out of the Ophioglossæ. They were
-more highly developed than all other ferns, and form the transition to
-flowering plants, which must have developed out of them. Next to the
-frondose ferns they took the largest part in the composition of the
-palæolithic fern forests. This class also contains, as does the class of
-reed ferns, three nearly related but still very different orders, of
-which only one now exists, the two others having become extinct towards
-the end of the Carboniferous period. The scaled ferns still existing
-belong to the order of the club-mosses (Lycopodiaceæ). They are mostly
-small, pretty moss-like plants, whose tender, many-branched stalk creeps
-in curves on the ground like a snake, and is densely encompassed and
-covered by small scaly leaves. The pretty creeping Lycopodium of our
-woods, which mountain tourists twine round their hats, is known to all,
-as also the still more delicate Selaginella, which under the name of
-creeping moss is used to adorn the soil of our hot-houses in the form of
-a thick carpet. The largest _club-mosses_ of the present day are found
-in the Sunda Islands, where their stalks rise to the height of
-twenty-five feet, and attain half a foot in thickness. But in the
-primary and secondary periods even larger trees of this kind were widely
-distributed, the most ancient of which probably were the progenitors of
-the pines (Lycopodites). The most important dimensions were, however,
-attained by the class of scale trees (Lepidodendreæ), and by the seal
-trees (Sigillarieæ). These two orders, with a few species, appear in the
-Devonian period, but do not attain their immense and astonishing
-development until the Carboniferous period, and become extinct towards
-the end of it, or in the Permian period directly following upon it. The
-scale trees, or Lepidodendreæ, were probably more closely related to
-club-mosses than to Sigillarieæ. They grew into splendid, straight,
-unbranching trunks which divided at the top into numerous forked
-branches. They bore a large crown of scaly leaves, and like the trunk
-were marked in elegant spiral lines by the scars left at the base of the
-leaf stalks which had fallen off. We know of scale-marked trees from
-forty to sixty feet in length, and from twelve to fifteen feet in
-diameter at the root. Some trunks are said to be even more than a
-hundred feet in length. In the coal are found still larger accumulations
-of the no less highly developed but more slender trunks of the
-remarkable seal trees, Sigillarieæ, which in many places form the
-principal part of coal seams. Their roots were formerly described as
-quite a distinct vegetable form (under the name of Stigmaria). The
-Sigillarieæ are in many respects very like the scale-trees, but differ
-from them and from ferns in general in many ways. They were possibly
-closely related to the extinct Devonian _Lycopterideæ_, combining
-characteristic peculiarities of the club-mosses and the frondose ferns,
-which Strasburger considers as the hypothetical primary form of
-flowering plants.
-
-In leaving the dense forests of the primary period, which were
-principally composed of frond ferns (Lepidodendreæ and Sigillarieæ), we
-pass onwards to the no less characteristic pine forests of the secondary
-period. Thus we leave the domain of the Cryptogamia, the plants forming
-neither flowers nor seeds, and enter the second main division of the
-vegetable kingdom, namely, the sub-kingdom of the _Phanerogamia_,
-_flowering plants_ forming seeds. This division, so rich in forms,
-containing the principal portion of the present vegetable world, and
-especially the majority of plants living on land, is certainly of a much
-more recent date than the division of Cryptogamia. For it can have
-developed out of the latter only in the course of the palæolithic
-period. We can with full assurance maintain that, during the whole
-archilithic period, hence during the first and longer half of the
-organic history of the earth, no flowering plants as yet existed, and
-that they first developed during the primary period out of Cryptogamia
-of the fern kind. The anatomical and embryological relation of
-Phanerogamia to the latter is so close, that from it we can with
-certainty infer their genealogical connection, that is, their true blood
-relationship. Flowering plants cannot have directly arisen out of
-thallus plants, nor out of mosses; but only out of ferns, or Filicines.
-Most probably the scaled ferns, or Lepidophyta, and more especially
-amongst these the Lycopodiaceæ, forms closely related to the
-Selaginella of the present day, have been the direct progenitors of the
-Phanerogamia.
-
-On account of its anatomical structure and its embryological
-development, the sub-kingdom of the Phanerogamia has for a long time
-been divided into two large branches, into the _Gymnosperms_, or plants
-with naked seeds, and the _Angiosperms_, or plants with enclosed seeds.
-The latter are in every respect more perfect and more highly organized
-than the former, and developed out of them only at a late date during
-the secondary period. The Gymnosperms, both anatomically and
-embryologically, form the transition group from Ferns to Angiosperms.
-
-The lower, more imperfect, and the older of the two main classes of
-flowering plants, that of the _Archispermeæ_, or _Gymnosperms_ (with
-naked seeds), attained its most varied development and widest
-distribution during the mesolithic or secondary epoch. It was no less
-characteristic of this period, than was the fern group of the preceding
-primary, and the Angiosperms of the succeeding tertiary, epoch. Hence we
-might call the secondary epoch that of Gymnosperms, or after its most
-important representatives, the era of Pine Forests. The Gymnosperms are
-divided into three classes: the Coniferæ, Cycadeæ, and Gnetaceæ. We find
-fossil remains of the pines, or Conifers, and of the Cycads, even in
-coal, and must infer from this that the transition from scaled ferns to
-Gymnosperms took place during the Coal, or possibly even in the Devonian
-period. However, the Gymnosperms play but a very subordinate part during
-the whole of the primary epoch, and do not predominate over Ferns until
-the beginning of the secondary epoch.
-
-Of the two classes of Gymnosperms just mentioned, that of the _Palm
-Ferns_ (Zamiæ, or Cycadeæ) stands at the lowest stage, and is directly
-allied to ferns, as the name implies, so that some botanists have
-actually included them in the fern group. In their external form they
-resemble palms, as well as tree ferns (or tree-like frond ferns), and
-are adorned by a crown of feathery leaves, which is placed either on a
-thick, short trunk, or on a slender, simple trunk like a pillar. At the
-present day this class, once so rich in forms, is but scantily
-represented by a few forms living in the torrid zones, namely, by the
-coniferous ferns (Zamia), the thick-trunked bread-tree (Encephalartos),
-and the slender-trunked Caffir bread-tree (Cycas). They may frequently
-be seen in hot-houses, and are generally mistaken for palms. A much
-greater variety of forms than occurs among the still existing palm ferns
-(Cycadeæ) is presented by the extinct and fossil Cycads, which occurred
-in great numbers more towards the middle of the secondary period, during
-the Jura, and which at that time principally determined the character of
-the forests.
-
-The class of _Pines_, or _coniferous trees_ (Coniferæ), has preserved
-down to our day a greater variety of forms than have the palm ferns.
-Even at the present time the trees belonging to it--cypresses, juniper
-trees, and trees of life (Thuja), the box and ginko trees (Salisburya),
-the araucaria and cedars, but above all the genus Pinus, which is so
-rich in forms, with its numerous and important species, spruces, pines,
-firs, larches, etc.--still play a very important part in the most
-different parts of the earth, and almost of themselves constitute
-extensive forests. Yet this development of pines seems but weak in
-comparison with the predominance which the class had attained over other
-plants during the early secondary period, that of the Trias. At that
-time mighty coniferous trees--with but proportionately few genera and
-species, but standing together in immense masses of individuals--formed
-the principal part of the mesolithic forests. This fact justifies us in
-calling the secondary period the "era of the pine forests," although the
-remains of Cycadeæ predominate over those of coniferous trees in the
-Jura period.[2]
-
-From the pine forests of the mesolithic, or secondary period, we pass on
-into the leafy forests of the cænolithic, or tertiary period, and we
-arrive thus at the consideration of the sixth and last class of the
-vegetable kingdom, that of the _Metaspermæ_, _Angiospermæ_, or _plants
-with enclosed seeds_. The first certain and undoubted fossils of plants
-with enclosed seeds are found in the strata of the chalk system, and
-indeed we here find, side by side, remains of the two classes into which
-the main class of Angiosperms is generally divided, namely, the _one
-seed-lobed plants_, or _monocotylæ_, and the _two seed-lobed plants_, or
-_dicotylæ_. However, the whole group probably originated at an earlier
-period during the Trias. For we know of a number of doubtful and not
-accurately definable fossil remains of plants from the Oolitic and Trias
-(sic) periods, which some botanists consider to be Monocotylæ, whilst
-others consider them as Gymnosperms. In regard to the two classes of
-plants with enclosed seeds, the Monocotylæ and Dicotylæ, it is
-exceedingly probable that the Dicotyledons developed out of the
-Gnetaceæ, but that the Monocotyledons developed later out of a branch of
-the dicotyledons.
-
-The class of _one seed-lobed plants_ (Monocotylæ, or Monocotyledons,
-also called Endogenæ) comprises those flowering plants whose seeds
-possess but one germ leaf or seed lobe (cotyledon). Each whorl of its
-flower contains in most cases _three_ leaves, and it is very probable
-that the mother plants of all Monocotyledons possessed a regular triple
-blossom. The leaves are mostly simple, and traversed by simple, straight
-bunches of vessels or "nerves." To this class belong the extensive
-families of the rushes, grasses, lilies, irids, and orchids, further a
-number of indigenous aquatic plants, the water-onions, sea grasses,
-etc., and finally the splendid and highly developed families of the
-Aroideæ and Pandaneæ, the bananas and palms. On the whole, the class of
-Monocotyledons--in spite of the great variety of forms which it
-developed, both in the tertiary and the present period--is much more
-simply organized than the class of the Dicotyledons, and its history of
-development also offers much less of interest. As their fossil remains
-are for the most part difficult to recognize, it still remains at
-present an open question in which of the three great secondary
-periods--the Trias, Jura, or chalk period--the Monocotyledons
-originated. At all events they existed in the chalk period as surely as
-did the Dicotyledons.
-
-[Illustration:
-
-  _Haeckel History of Creation._
-
-  _PL. V._
-
-Relative lengths of the 5 Epochs in percentages.
-
-  Quarternary Epoch  0.5
-  Tertiary Epoch     2.3
-  Secondary Epoch   11.5
-  Primary Epoch     32.1
-  Primordial Epoch  53.6
-                   -----
-          _Total_  100.0
-
-  Single-stemmed or
-  MONOPHYLETIC PEDIGREE
-  of the
-  VEGETABLE KINGDOM
-  based on Palæontology.]
-
-The second class of plants with enclosed seeds, the _two seed-lobed_
-(Dicotylæ, or Dicotyledons, also called Exogenæ) presents much greater
-historical and anatomical interest in the development of its subordinate
-groups. The flowering plants of this class generally possess, as their
-name indicates, two seed lobes or germ leaves (cotyledons). The number
-of leaves composing its blossom is generally not three, as in most
-Monocotyledons, but four, five, or a multiple of those numbers. Their
-leaves, moreover, are generally more highly differentiated and more
-composite than those of the Monocotyledons; they are traversed by
-crooked, branching bunches of vessels or "veins." To this class belong
-most of the leafed trees, and as they predominate in the tertiary period
-as well as, at present, over the Gymnosperms and Ferns, we may call the
-cænolithic period that of leafed forests.
-
-Although the majority of Dicotyledons belong to the most highly
-developed and most perfect plants, still the lowest division of them is
-directly allied to the Gymnosperms, and particularly to the Gnetaceæ. In
-the lower Dicotyledons, as in the case of the Monocotyledons, calyx and
-corolla are as yet not differentiated. Hence they are called _Apetalous_
-(Monochlamydeæ, or Apetalæ). This sub-class must therefore doubtless be
-looked upon as the original group of the Angiosperms, and existed
-probably even during the Trias and Jura periods. Among them are most of
-the leafed trees bearing catkins--birches and alders, willows and
-poplars, beeches and oaks; further, the plants of the nettle
-kind--nettles, hemp, and hops, figs, mulberries, and elms; finally,
-plants like the spurges, laurels, and amaranth.
-
-It was not until the chalk period that the second and more perfect class
-of the Dicotyledons appeared, namely, the _group with corollas_
-(Dichlamydeæ, or Corollifloræ). These arose out of the Apetalæ from the
-simple cover of the blossoms of the latter becoming differentiated into
-calyx and corolla. The sub-class of the Corollifloræ is again divided
-into two large main divisions or legions, each of which contains a large
-number of different orders, families, genera, and species. The first
-legion bears the name of star-flowers, or Diapetalæ, the second that of
-the bell-flowers, or Gamopetalæ.
-
-The lower and less perfect of the two legions of the Corollifloræ are
-the star-flowers (also called Diapetalæ or Dialypetalæ). To them belong
-the extensive families of the Umbelliferæ, or umbrella-worts (wild
-carrot, etc.), the Cruciferæ, or cruciform blossoms (cabbage, etc.);
-further, the Ranunculaceæ (buttercups) and Crassulaceæ, the Mallows and
-Geraniums, and, besides many others, the large group of Roses (which
-comprise, besides roses, most of our fruit trees), and the Pea-blossoms
-(containing, among others, beans, clover, genista, acacia, and mimosa).
-In all these Diapetalæ the blossom-leaves remain separate, and never
-grow together, as is the case in the Gamopetalæ. These latter developed
-first in the tertiary period out of the Diapetalæ, whereas the Diapetalæ
-appeared in the chalk period together with the Apetalæ.
-
-The highest and most perfect group of the vegetable kingdom is formed by
-the second division of the Corollifloræ, namely, the legion of
-bell-flowers (Gamopetalæ, also called Monopetalæ or Sympetalæ). In this
-group the blossom-leaves, which in other plants generally remain
-separate, grow regularly together into a more or less bell-like,
-funnel-shaped, or tubular flower. To them belong, among others, the
-Bell-flowers and Convolvulus, Primroses and Heaths, Gentian and
-Honeysuckle, further the family of the Olives (olive trees, privet,
-elder, and ash), and finally, besides many other families, the
-extensive division of the Lip-blossoms (Labiatæ) and the Composites. In
-these last the differentiation and perfection of the Phanerogamic
-blossoms attain their highest stage of development, and we must
-therefore place them at the head of the vegetable kingdom, as the most
-perfect of all plants. In accordance with this, the legion of the
-Gamopetalæ appear in the organic history of the earth later than all the
-main groups of the vegetable kingdom--in fact, not until the cænolithic
-or tertiary epoch. In the earliest tertiary period the legion is still
-very rare, but it gradually increases in the mid-tertiary, and attains
-its full development only in the latest tertiary and the quaternary
-period.
-
-Now if, having reached our own time, we look back upon the _whole
-history of the development of the vegetable kingdom_, we cannot but
-perceive in it a _grand confirmation of the Theory of Descent_. The two
-great principles of organic development which have been pointed out as
-the necessary results of natural selection in the Struggle for Life,
-namely, the laws of _differentiation_ and _perfecting_, manifest
-themselves everywhere in the development of the larger and smaller
-groups of the natural system of plants. In each larger or smaller period
-of the organic history of the earth, the vegetable kingdom increases
-both in _variety_ and _perfection_, as a glance at Plate IV. will
-clearly show. During the whole of the long primordial period there
-existed only the lowest and most imperfect group, that of the Algæ. To
-these are added, in the primary period, the higher and more perfect
-Cryptogamia, especially the main-class of Ferns. During the coal period
-the Phanerogamia begin to develop out of the latter; at first, however,
-they are represented only by the lower main-class, that of Gymnosperms.
-It was not until the secondary period that the higher main-class, that
-of Angiosperms, arose out of them. Of these also there existed at first
-only the lower groups without distinct corollas, the Monocotyledons and
-the Apetalæ. It was not until the chalk period that the higher
-Corollifloræ developed out of the latter. But even this most highly
-developed group is represented, in the chalk period, only by the lower
-stage of Star-flowers, or Diapetalæ, and only at quite a late date, in
-the tertiary period, did the more highly developed Bell-blossoms,
-Gamopetalæ, arise out of them, which at the same time are the most
-perfect of all flowering plants. Thus, in each succeeding later division
-of the organic history of the earth the vegetable kingdom gradually rose
-to a higher degree of perfection and variety.
-
-
-
-
-CHAPTER XVIII.
-
-PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-I. ANIMAL-PLANTS AND WORMS.
-
-
-  The Natural System of the Animal Kingdom.--Linnæus and Lamarck's
-  Systems.--The Four Types of Bär and Cuvier.--Their Increase to
-  Seven Types.--Genealogical Importance of the Seven Types as
-  Independent Tribes of the Animal Kingdom.--Derivation of
-  Zoophytes and Worms from Primæval Animals.--Monophyletic and
-  Polyphyletic Hypothesis of the Descent of the Animal
-  Kingdom.--Common Origin of the Four Higher Animal Tribes out of
-  the Worm Tribe.--Division of the Seven Animal Tribes into
-  Sixteen Main Classes, and Thirty-eight Classes.--Primæval
-  Animals (Monera, Amoebæ, Synamoebæ), Gregarines, Infusoria,
-  Planæades, and Gastræades (Planula and Gastrula).--Tribe of
-  Zoophytes.--Spongiæ (Mucous Sponges, Fibrous Sponges, Calcareous
-  Sponges).--Sea Nettles, or Acalephæ (Corals, Hood-jellies,
-  Comb-jellies).--Tribe of Worms.
-
-
-The natural system of organisms which we must employ in the animal as
-well as in the vegetable kingdom, as a guide in our genealogical
-investigations, is in both cases of but recent origin, and essentially
-determined by the progress of comparative anatomy and ontogeny (the
-history of individual development) during the present century. Almost
-all the attempts at classification made in the last century followed the
-path of the artificial system, which was first established in a
-consistent manner by Charles Linnæus. The artificial system differs
-essentially from the natural one, in the fact that it does not make the
-whole organization and the internal structure (depending upon the blood
-relationship) the basis of classification, but only employs individual,
-and for the most part external, characteristics, which readily strike
-the eye. Thus Linnæus distinguished his twenty-four classes of the
-vegetable kingdom principally by the number, formation, and combination
-of the stamens. In like manner he distinguished six classes in the
-animal kingdom principally by the nature of the heart and blood. These
-six classes were: (1) Mammals; (2) Birds; (3) Amphibious Animals; (4)
-Fishes; (5) Insects; and (6) Worms.
-
-But these six animal classes of Linnæus are by no means of equal value,
-and it was an important advance when, at the end of the last century,
-Lamarck comprised the first four classes as vertebrate animals
-(Vertebrata), and put them in contrast with the remaining animals (the
-insects and worms of Linnæus), of which he made a second main
-division--the invertebrate animals (Invertebrata). In reality Lamarck
-thus agreed with Aristotle, the father of Natural History, who had
-distinguished these two main groups, and called the former
-_blood-bearing animals_, the latter _bloodless animals_.
-
-The next important progress towards a natural system of the animal
-kingdom was made some decades later by two most illustrious zoologists,
-Carl Ernst Bär and George Cuvier. As has already been remarked, they
-established, almost simultaneously and independently of one another, the
-proposition that it was necessary to distinguish several completely
-distinct main groups in the animal kingdom, each of which possessed an
-entirely peculiar type or structure (compare above, vol. i. p. 53). In
-each of these main divisions there is a tree-shaped and branching
-gradation from most simple and imperfect forms to those which are
-exceedingly composite and highly developed. The _degree of development_
-within each type is quite independent of the peculiar _plan of
-structure_, which forms the basis of the type and gives it a special
-characteristic. The "type" is determined by the peculiar relations in
-position of the most important parts of the body, and the manner in
-which the organs are connected. The degree of development, however, is
-dependent upon the greater or less division of labour among organs, and
-on the differentiation of the plastids and organs. This extremely
-important and fruitful idea was established by Bär, who relied more
-distinctly and thoroughly upon the history of individual development
-than did Cuvier. Cuvier based his argument upon the results of
-comparative anatomy. But neither of them recognized the true cause of
-the remarkable relationships pointed out by them, which is first
-revealed to us by the Theory of Descent. It shows us that the common
-_type_ or plan of structure is determined by _inheritance_, and the
-degree of development or differentiation by _adaptation_. (Gen. Morph.
-ii. 10).
-
-Both Bär and Cuvier distinguished four different types in the animal
-kingdom, and divided it accordingly into four great main divisions
-(branches or circles). The first of these is formed by the vertebrate
-animals (Vertebrata), and comprises Linnæus' first four
-classes--mammals, birds, amphibious animals, and fishes. The second type
-is formed by the articulated animals (Articulata), containing Linnæus'
-insects, consequently the six-legged insects, and also the myriopods,
-spiders, and crustacea, but besides these, a large number of the worms,
-especially the ringed worms. The third main division comprises the
-molluscous animals (Mollusca)--slugs, snails, mussels, and some kindred
-groups. Finally, the fourth and last circle of the animal kingdom
-comprises the various radiated animals (Radiata), which at first sight
-differ from the three preceding types by their radiated, flower-like
-form of body. For while the bodies of molluscs, articulated animals, and
-vertebrated animals consist of two symmetrical lateral halves--of two
-counterparts or antimera, of which the one is the mirror of the
-other--the bodies of the so-called radiated animals are composed of more
-than two, generally of four, five, or six counterparts grouped round a
-common central axis, as in the case of a flower. However striking this
-difference may seem at first, it is, in reality, a very subordinate one,
-and the radial form has by no means the same importance in all "radiated
-animals."
-
-The establishment of these natural main groups or types of the animal
-kingdom by Bär and Cuvier was the greatest advance in the classification
-of animals since the time of Linnæus. The three groups of vertebrated
-animals, articulated animals, and molluscs are so much in accordance
-with nature that they are retained, even at the present day, little
-altered in extent. But a more accurate knowledge soon showed the utterly
-unnatural character of the group of the radiated animals. Leuckart, in
-1848, first pointed out that two perfectly distinct types were
-confounded under the name, namely, the _Star-fishes_ (Echinoderma)--the
-sea-stars, lily encrinites, sea-urchins, and sea-cucumbers; and, on the
-other hand, the _Animal-plants_, or _Zoophytes_ (Coelenterata or
-Zoophyta)--the sponges, corals, hood-jellies, and comb-jellies. At the
-same time, Siebold united the Infusoria with the Rhizopoda, under the
-name of Protozoa (lowest animals), into a special main division of the
-animal kingdom. By this the number of animal types was increased to six.
-It was finally increased to seven by the fact that modern zoologists
-separated the main division of the articulated animals into two groups:
-(_a_) those possessing _articulated feet_ (Arthropoda), corresponding to
-Linnæus' Insects, namely, the Flies (with six legs), Myriopods, Spiders,
-and Crustacea; and (_b_) the footless _Worms_ (Vermes), or those
-possessing non-articulated feet. These latter comprise only the real or
-genuine Worms (ring-worms, round worms, planarian worms, etc.), and
-therefore in no way correspond with the Worms of Linnæus, who had
-included the molluscs, the radiates, and many other lower animals under
-this name.
-
-Thus, according to the views of modern zoologists, which are given in
-all recent manuals and treatises on zoology, the animal kingdom is
-composed of seven completely distinct main divisions or types, each of
-which is distinguished by a characteristic plan of structure peculiar to
-it, and perfectly distinct from every one of the others. In the natural
-system of the animal kingdom--which I shall now proceed to explain as
-its probable pedigree--I shall on the whole agree with this usual
-division, but not without some modifications, which I consider very
-important in connection with genealogy, and which are rendered
-absolutely necessary in consequence of our view as to the history of the
-development of animals.
-
-We evidently obtain the greatest amount of information concerning the
-_pedigree of the animal kingdom_ (as well as concerning that of the
-vegetable kingdom) from comparative anatomy and ontogeny. Besides
-these, palæontology also throws much valuable light upon the historical
-succession of many of the groups. From numerous facts in comparative
-anatomy, we may, in the first place, infer the _common origin of all
-those animals which belong to one of the seven "types."_ For in spite of
-all the variety in the external form developed within each of these
-types, the essential relative position of the parts of the body which
-determines the type, is so constant, and agrees so completely in all the
-members of every type, that on account of their relations of form alone
-we are obliged to unite them, in the natural system, into a single main
-group. But we must certainly conclude, moreover, that this conjunction
-also has its expression in the pedigree of the animal kingdom. For the
-true cause of the intimate agreement in structure can only be the actual
-blood relationship. Hence we may, without further discussion, lay down
-the important proposition that all animals belonging to one and the same
-circle or type must be descended from one and the same original primary
-form. In other words, the idea of the circle or type, as it is employed
-in zoology since Bär and Cuvier's time to designate the few principal
-main groups or "sub-kingdoms" of the animal kingdoms, coincides with the
-idea of "tribe" or "phylum," as employed by the Theory of Descent.
-
-If, then, we can trace all the varieties of animal forms to these seven
-fundamental forms, the following question next presents itself to us as
-a second phylogenetic problem--Where do these seven animal tribes come
-from? Are they seven original primary forms of an entirely independent
-origin, or are they also distantly related by blood to one another?
-
-[Illustration: _PL. VI._
-
-Historical Growth of the six great stems of Animals. _See the
-Explanation._]
-
-At first we might be inclined to answer this question in a
-_polyphyletic_ sense, by saying that we must assume, for each of the
-seven great animal tribes, at least one independent primary form
-completely distinct from the others. On further considering this
-difficult problem, we arrive in the end at the notion of a
-_monophyletic_ origin of the animal kingdom, viz., that these seven
-primary forms are connected at their lowest roots, and that they are
-derived from a single, common primæval form. _In the animal as well as
-in the vegetable kingdom, when closely and accurately considered, the
-monophyletic hypothesis of descent is found to be more satisfactory than
-the polyphyletic hypothesis._
-
-It is _comparative ontogeny_ (embryology) which first and foremost leads
-to the assumption of the monophyletic origin of the whole animal kingdom
-(the Protista excepted of course). The zoologist who has thoughtfully
-compared the history of the individual development of various animals,
-and has understood the importance of the biogenetic principle (p. 33),
-cannot but be convinced that a common root must be assumed for the seven
-different animal tribes, and that all animals, including man, are
-derived from a single, common primary form. The result of the
-consideration of the facts of embryology, or ontogeny, is the following
-genealogical or phylogenetic hypothesis, which I have put forward and
-explained in detail in my "Philosophy of Calcareous Sponges" (Monograph
-of the Calcareous Sponges, vol. i. pp. 464, 465, etc.,--"the Theory of
-the Layers of the Embryo, and the Pedigree of Animals").
-
-The first stage of organic life in the Animal kingdom (as in the
-Vegetable and Protista kingdoms) was formed by perfectly simple
-_Monera_, originating by spontaneous generation. The former existence
-of this simplest animal form is, even at present, attested by the fact
-that the egg-cell of many animals loses its kernel directly after
-becoming fructified, and thus relapses to the lower stage of development
-of a cytod without a kernel, like a Moneron. This remarkable occurrence
-I have interpreted, according to the law of latent inheritance (vol. i.
-p. 205), as a phylogenetic _relapse_ of the cellular form into the
-original form of a cytod. The _Monerula_, as we may call this egg-cytod
-without a kernel, repeats then, according to the biogenetic principle
-(vol. ii. p. 33), the most ancient of all animal forms, the common
-primary form of the animal kingdom, namely, the Moneron.
-
-The second ontogenetic process consists in a new kernel being formed in
-the Monerula, or egg-cytod, which thus returns again to the value of a
-true _egg-cell_. According to this, we must look upon the simple animal
-cell, containing a kernel, or the single-celled primæval animal--which
-may still be seen in a living state in the _Amoebæ_ of the present
-day--as the _second_ step in the series of phylogenetic forms of the
-animal kingdom. Like the still living simple Amoebæ, and like the naked
-egg-cells of many lower animals (for example, of Sponges and Medusæ,
-etc.), which cannot be distinguished from them, the remote phyletic
-primary Amoebæ also were perfectly simple naked-cells, which moved about
-in the Laurentian primæval ocean, creeping by means of the ever-changing
-processes of their body-substance, and nourishing and propagating
-themselves in the same way as the Amoebæ of the present day. (Compare
-vol. i. p. 188, and vol. ii. p. 54.) The existence of this Amoeba-like,
-_single-celled primary form_ of the whole animal kingdom is unmistakably
-indicated by the exceedingly important fact that the egg of all animals,
-from those of sponges and worms up to those of the ant and man, is a
-simple cell.
-
-Thirdly, from the "single-cell" state arose the _simplest multicellular
-state_, namely, a heap or a small community of simple, equi-formal, and
-equivalent cells. Even at the present day, in the ontogenetic
-development of every animal egg-cell, there first arises a globular heap
-of equi-formal naked cells, by the repeated self-division of the primary
-cell. (Compare vol. i. p. 190 and the Frontispiece, Fig. 3.) We called
-this accumulation of cells the _mulberry state_ (Morula), because it
-resembles a mulberry or blackberry. This Morula-body occurs in the same
-simple form in all the different tribes of animals, and on account of
-this most important circumstance we may infer--according to the
-biogenetic principle--that the _most ancient, many-celled, primary form
-of the animal kingdom_ resembled a Morula like this, and was in fact a
-simple heap of Amoeba-like primæval cells, one similar to the other. We
-shall call this most ancient community of Amoebæ--this most simple
-accumulation of animal cells--which is recapitulated in individual
-development by the Morula--the _Synamoeba_.
-
-Out of the Synamoebæ, in the early Laurentian period, there afterwards
-developed a fourth primary form of the animal kingdom, which we shall
-call the ciliated germ (Planæa). This arose out of the Synamoeba by the
-outer cells on the surface of the cellular community beginning to extend
-vibrating fringes called cilia, and becoming "ciliated cells," and thus
-differentiating from the inner and unchanged cells. The Synamoebæ
-consisted of completely equi-formed and naked cells, and crept about
-slowly, at the bottom of the Laurentian primæval ocean, by means of
-movements like those of an Amoeba. The Planæa, on the other hand,
-consisted of two kinds of different cells--inner ones like the Amoebæ,
-and external "ciliated cells." By the vibrating movements of the cilia
-the entire multicellular body acquired a more rapid and stronger motion,
-and passed over from the creeping to the swimming mode of locomotion. In
-exactly the same manner the _Morula_, in the ontogenesis of lower
-animals, still changes into a ciliated form of larva, which has been
-known, since the year 1847, under the name of _Planula_. This Planula is
-sometimes a globular, sometimes an oval body, which swims about in the
-water by means of a vibrating movement; the fringed (ciliated) and
-smaller cells of the surface differ from the larger inner cells, which
-are unfringed. (Fig. 4 of the Frontispiece.)
-
-Out of this Planula, or fringed larva, there then develops, in animals
-of all tribes, an exceedingly important and interesting animal form,
-which, in my Monograph of the Calcareous Sponges, I have named
-_Gastrula_ (that is, larva with a stomach or intestine). (Frontispiece,
-Fig. 5, 6). This Gastrula externally resembles the Planula, but differs
-essentially from it in the fact that it encloses a cavity which opens to
-the outside by a mouth. The cavity is the "_primary intestine_," or
-"primary stomach," the _progaster_, the first beginning of the
-alimentary canal; its opening is the "_primary mouth_" (prostoma). The
-wall of the progaster consists of two layers of cells: an outer layer of
-smaller ciliated cells (outer skin, or ectoderm), and of an inner layer
-of larger non-ciliated cells (inner skin, or entoderm). This exceedingly
-important larval form, the "Gastrula," makes its appearance in the
-ontogenesis of all tribes of animals--in Sponges, Medusæ, Corals, Worms,
-Sea-squirts, Radiated animals, Molluscs, and even in the lowest
-Vertebrata (Amphioxus: compare p. 200, Plate XII., Fig. _B_ 4; see also
-in the same place the Ascidian, Fig. _A_ 4).
-
-
-  Definition of the _forms_      |   +Ontogenesis.+             |    +Phylogenesis.+
-  of the five first stages       | The five first stages        | The five first stages
-  of the development of          | of the individual            | of the phyletic or
-  the animal body.               | development.                 | historical development.
-  -------------------------------+------------------------------+------------------------
-                                 |                              |
-  _First Stage of Development._  |             1.               |          1.
-                                 |         +Monerula.+          |       +Moneron.+
-  A simple cytod (a              |                              |
-  plastid without a kernel.)     | Animal egg without a         | Most ancient animal
-             |                   | kernel (when the egg-kernel  | Monera, originating by
-             |                   | has disappeared,             | spontaneous generation.
-             |                   | after being fructified).     |          |
-             |                   |             |                |          |
-             |                   |             |                |          |
-  _Second Stage of Development._ |             2.               |          2.
-                                 |          +Ovulum.+           |       +Amoebæ.+
-  A simple cell (a               |                              |
-  plastid containing a           | Animal egg with kernel       | Animal Amoebæ.
-  kernel.)                       | (a simple egg-cell).         |          |
-              |                  |             |                |          |
-              |                  |             |                |          |
-              |                  |             |                |          |
-  _Third Stage of Development._  |             3.               |          3.
-                                 |          +Morula.+           |     +Synamoeba.+
-  A community (an                |     (_Mulberry form._)       |
-  aggregation of identical       |                              | An aggregation of
-  simple cells).                 | Globular heap of homogeneous | Amoebæ.
-              |                  | "cleavage spheres."          |          |
-              |                  |             |                |          |
-              |                  |             |                |          |
-  _Fourth Stage of Development._ |             4.               |          4.
-                                 |          +Planula.+          |       +Planæa.+
-  A solid or bladder-shaped,     |     (_Ciliated larva_.)      |
-  globular, or oval              |                              | Many-celled primæval
-  body, _composed of two         | Many-celled larva            | animal without
-  kinds of different cells_:     | without mouth, composed      | mouth, composed of
-  externally ciliated,           | of different cells.          | two kinds of different
-  internally non-ciliated        |             |                | cells.
-  cells.                         |             |                |          |
-              |                  |             |                |          |
-              |                  |             |                |          |
-  _Fifth Stage of Development._  |             5.               |          5.
-                                 |          +Gastrula.+         |       +Gastræa.+
-  A globular or oval             |     (_Larva with mouth._)    |
-  _body with simple intestinal   | Many-celled with intestines  | Many-celled primæval
-  cavity and mouth-opening.      | and mouth; intestinal        | animal with intestine
-  Body wall composed             | wall with two                | and mouth; intestinal
-  of two layers_; an             | layers.                      | wall with two
-  externally ciliated ectoderm   |                              | layers. (Primary form
-  (dermal layer), an             |                              | of zoophytes and
-  internally non-ciliated        |                              | worms.)
-  entoderm (gastral layer).      |                              |
-
-
-From the ontogenetic occurrence of the Gastrula in the most different
-animal classes, from Zoophytes up to Vertebrata, we may, according to
-the biogenetic principle, safely draw the conclusion that during the
-Laurentian period there existed a common primary form of the six higher
-animal tribes, which in all essential points was formed like the
-Gastrula, and which we shall call the Gastræa. This Gastræa possessed a
-perfectly simple globular or oval body, which enclosed a simple cavity
-of like form, namely, the progaster; at one of the poles of the
-longitudinal axis the primary intestine opened by a mouth which served
-for the reception of nutrition. The body wall (which was also the
-intestinal wall) consisted of two layers of cells, the unfringed
-entoderm, or intestinal layer, and the fringed ectoderm, or skin-layer;
-by the motion of the cilia or fringes of the latter the Gastræa swam
-about freely in the Laurentian ocean. Even in those higher animals, in
-the ontogenesis of which the original Gastrula form has disappeared,
-according to the laws of abbreviated inheritance (vol. i. p. 212), the
-composition of the Gastræa body has been transmitted to the phase of
-development which directly arises out of the Morula. This phase is an
-oval or round disc consisting of two cell-layers or membranes: the outer
-cell-layer, the _animal or dermal layer_ (ectoblast), corresponds to the
-ectoderm of the Gastræa; out of it develops the external, loose skin
-(epidermis), with its glands and appendages, as well as the central
-nervous system. The inner cell-layer, the _vegetative or intestinal
-layer_ (hypoblast), is originally the entoderm of the Gastræa; out of it
-develops the inner membrane (epithelium) of the intestinal canal and its
-glands. (Compare my Monograph of the Calcareous Sponges, vol. i. p. 466,
-etc.)
-
-By ontogeny we have already gained five primordial stages of development
-of the animal kingdom: (1) the Moneron; (2) the Amoeba; (3) the
-Synamoeba; (4) the Planæa; and (5) the Gastræa. The former existence of
-these five oldest primary forms, which succeeded one another, and which
-must have lived in the Laurentian period, follows as a consequence of
-the biogenetic principle; that is to say, from the parallelism and the
-mechanico-causal connection of ontogenesis and phylogenesis. (Compare
-vol. i. p. 309.) In our genealogical system of the animal kingdom we may
-class all these animal forms, long since extinct, and, which on account
-of the soft nature of their bodies could leave no fossil remains, among
-the tribe of Primæval animals (Protozoa), which also comprises the still
-living Infusoria and Gregarinæ.
-
-The phyletic development of the six higher animal tribes, which are all
-derived from the Gastræa, deviated at this point in two directions. In
-other words, the _Gastræads_ (as we may call the group of forms
-characterized by the Gastræa-type of structure), divided into two
-divergent lines or branches; the one branch of Gastræads gave up free
-locomotion, adhered to the bottom of the sea, and thus, by adopting an
-adhesive mode of life, gave rise to the _Protascus_, the common primary
-form of the _Animal-plants_ (Zoophyta). The other branch of the
-Gastræads retained free locomotion, did not become adherent and later
-on developed into the _Prothelmis_, the common primary form of _Worms_
-(Vermes). (Compare p. 133.)
-
-This latter tribe (as limited by modern zoology) is of the greatest
-interest in the study of genealogy. For among Worms, as we shall see
-later, there are, besides very numerous peculiar families, and besides
-many independent classes, also very remarkable forms, which may be
-considered as _forms of direct transition_ to the four higher animal
-tribes. Both comparative anatomy and the ontogeny of these worms enable
-us to recognize in them the nearest blood relations of those extinct
-animal forms which were the original primary forms of the four higher
-animal tribes. Hence these latter, the Molluscs, Star-fishes,
-Articulated animals, and Vertebrate animals, do not stand in any close
-blood relationship to one another, but have originated independently in
-four different places out of the tribe of Worms.
-
-In this way comparative anatomy and phylogeny lead us to the
-_monophyletic pedigree of the animal kingdom_, the outlines of which are
-given on p. 133. According to it the seven phyla, or tribes, of the
-animal kingdom are of different value in regard to genealogy. The
-original primary group of the whole animal kingdom is formed by the
-Primæval animals (Protozoa), including the Infusoria and Gastræads. Out
-of these latter arose the two tribes of Animal-plants (Zoophyta) and
-Worms as diverging branches. Out of four different groups of the Worm
-tribe, the four higher tribes of the animal kingdom were developed--the
-Star-fishes (Echinoderma) and Insects (Arthropoda) on the one hand, and
-the Molluscs (Mollusca) and Vertebrated animals (Vertebrata) on the
-other.
-
-Having thus sketched out the monophyletic pedigree of the animal kingdom
-in its most important features, we must now turn to a closer examination
-of the historical course of development which the seven tribes of the
-animal kingdom, and the classes distinguished in them, have passed
-through (p. 132). There is a much larger number of classes in the animal
-than in the vegetable kingdom, owing to the simple reason that the
-animal body, in consequence of its more varied and perfect vital
-activity, could differentiate and develop in very many more different
-directions than could the vegetable body. Thus, while we were able to
-divide the whole vegetable kingdom into six main classes and nineteen
-classes, we have to distinguish, at least, sixteen main classes and
-thirty-eight classes in the animal kingdom. These are distributed among
-the seven different tribes of the animal kingdom in the way shown in the
-Systematic Survey on pages 132 and 133.
-
-The group of _Primæval animals_ (Protozoa) within the compass which we
-here assign to this tribe, comprises the most ancient and the simplest
-primary forms of the animal kingdom; for example, the five oldest
-phyletic stages of development previously mentioned, and besides these
-the Infusoria and Gregarinæ, as well as all those imperfect animal
-forms, for which, on account of their simple and indifferent
-organization, no place can be found in any of the other six animal
-tribes. Most zoologists, in addition to these, include among the
-Protozoa a larger or smaller portion of those lowest organisms, which we
-mentioned in our neutral kingdom of Protista (in Chapter XVI.). But
-these Protista, especially the large division of the Rhizopoda, which
-are so rich in forms, cannot be considered as real animals for reasons
-previously given. Hence, if we here leave them out of the question, we
-may accept two main classes or provinces of real Protozoa, namely, _Egg
-animals_ (Ovularia) and _Germ animals_ (Blastularia). To the former
-belong the three classes of Archezoa, Gregarinæ, and Infusoria, to the
-latter the two classes of Planæads and Gastræads.
-
-SYSTEMATIC SURVEY
-
-_Of the 16 Main Classes and 38 Classes of the Animal Kingdom._
-
-
-  ------------------+-----------------------+----------------------+-----------------
-  _Tribes or Phyla_ |  _Main Classes_,      |    _Classes_         |_Systematic Name_
-      _of the_      |_Branches or Clades_   |     _of the_         |    _of the_
-  _Animal Kingdom._ |    _of the_           |  _Animal Kingdom._   |   _Classes._
-                    | _Animal Kingdom._     |                      |
-  ------------------+-----------------------+----------------------+------------------
-
-          A.        {
-       =Primæval=   { I. Egg-animals         { 1. Archaic animals     1. Archezoa
-       =Animals=    {    _Ovularia_          { 2. Gregarines          2. Gregarinæ
-                    {                        { 3. Infusoria           3. Infusoria
-      +Protozoa+    {
-                    {II. Mulberry animals    { 4. Planæads            4. Planæadas
-                    {    _Blastularia_       { 5. Gastræads           5. Gastræadas
-
-
-          B.        {
-        =Animal=    {   III. Sponges         { 6. Sponges             6. Porifera
-        =Plants=    {      _Spongiæ_         {
-                    {
-      +Zoophyta+    {  IV. Sea-nettles       { 7. Corals              7. Coralla
-                    {      _Acalephæ_        { 8. Hood-jellies        8. Hydromedusæ
-                    {                        { 9. Comb-jellies        9. Ctenophora
-
-
-          C.        {V. Bloodless worms      {10. Planary worms      10. Platyhelminthes
-        =Worms=     {   _Acoelomi_
-                    {                        {11. Round worms        11. Nemathelminthes
-      +Vermes+      {  VI. Blood-bearing     {12. Moss-polyps        12. Bryozoa
-                    {        worms           {13. Sac-worms          13. Tunicata
-                    {      _Coelomati_       {14. Proboscideans      14. Rhynchocoela
-                    {                        {15. Star-worms         15. Gephyrea
-                    {                        {16. Wheel animalcules  16. Rotatoria
-                    {                        {17. Ring-worms         17. Annelida
-
-
-          D.        {VII. Headless shellfish {18. Lamp-shells        18. Spirobranchia
-       =Molluscs=   {     _Acephala_         {19. Mussels            19. Lamellibranchia
-                    {
-      +Mollusca+    {  VIII. Head-bearing    {20. Snails             20. Cochlides
-                    {       _Eucephala_      {21. Cuttles            21. Cephalopoda
-
-
-          E.        {  IX. Ringed-arms       {22. Sea-stars          22. Asterida
-      =Star-fishes= {    _Colobrachia_       {23. Lily-stars         23. Crinoida
-                    {
-     +Echinoderma+  {      X. Armless        {24. Sea-urchins        24. Echinida
-                    {      _Lipobrachia_     {25. Sea-cucumbers      25. Holothuriæ
-
-
-          F.        {  XI. Gill-breathers    {26. Crab-fish          26. Crustacea
-      =Articulated= {       _Carides_        {
-        =Animals=   {
-                    {  XII. Tube-breathers   {27. Spiders            27. Arachnida
-      +Arthropoda+  {       _Tracheata_      {28. Centipedes         28. Myriopoda
-                    {                        {29. Flies              29. Insecta
-
-
-                    {   XIII. Skull-less     {30. Lancelets          30. Leptocardia
-                    {        _Acrania_       {
-          G.        {
-      =Vertebrate=  { XIV. Single-nostriled  {31. Lampreys           31. Cyclostoma
-       =Animals=    {    _Monorrhina_        {
-                    {
-     +Vertebrata+   {   XV. Amnion-less      {32. Fishes             32. Pisces
-                    {      _Anamnia_         {33. Mud-fish           33. Dipneusta
-                    {                        {34. Sea dragons        34. Halisauria
-                    {                        {35. Amphibians         35. Amphibia
-                    {
-                    { XVI. Amnion-bearing    {36. Reptiles           36. Reptilia
-                    {      _Amniota_         {37. Birds              37. Aves
-                    {                        {38. Mammals            38. Mammalia
-
-        ----------------------------------------------------------------
-
-                                         +Vertebrata+
-                                      (_Vertebrated animals_)
-                                           Craniota
-                                              |
-                       +Arthropoda+           |               +Mollusca+
-                  (_Articulated Animals_)     |              (_Molluscs_)
-  +Echinoderma+          Tracheata            |               Eucephala
-  (_Star-fishes_)           |                 |                   |
-                            |                 |                   |
-  Lipobrachia          Crustacea           Acrania                |
-       |      Annelida      |                 |  Tunicata     Acephala
-       |         |          |                 |      |  Bryozoa   |
-  Colobrachia    |          |                 |      |     |      |
-       | Gephyrea|          |   Rotatoria     \--v---/     \--v---/
-       |     |   |          |       |            |            |
-       |     |   |          |       |            |            |
-       \---------v-------------------/           \------v-----/
-                 |                                      |
-                 |               +Vermes+               |
-                 |              (_Worms_)               |
-                 \------------------v-------------------/
-                                    |
-                                    |
-                                 COELOMATI
-                      (_Worms with a body-cavity_)
-                                  |     Platyhelminthes
-                                  |            |
-                                  |            |
-                                  \-----v------/
-     +Zoophyta+                         |
-  (_Animal-Plants_)                 +ACOELOMI+
-  Spongiæ        Acalephæ   (_Worms without body-cavity_)
-     |              |                   |
-     |              |                   |
-     \------v-------/                   |
-            |                           |
-        Protascus                   Prothelmis
-            |                           |
-            |                           |
-            \-----------v---------------/
-                        |
-                        |          +Protozoa+
-                        |      (_Primæval animals_)
-                        |
-                        |/-------------^-------------\
-                     +GASTRÆA+
-                        |
-                        |         Infusoria
-                        |             |
-                     +PLANÆA+         |     Gregarinæ
-                        |             |        |
-                        |             |        |
-                   +SYNAMOEBÆ+         \----v---/
-                        |                  |
-                        |                  |
-                        \---------v--------/
-                               +AMOEBÆ+
-                                  |
-                               +MONERA+
-
-
-The first province of the Protozoa consists of the _Egg animals_
-(Ovularia); we include among them all _single-celled animals_, all
-animals whose body, in the fully developed state, possesses the
-form-value of a _simple plastid_ (of a cytod or a cell), also those
-simple animal forms whose body consists of an aggregation of several
-cells perfectly similar one to another.
-
-The _Archaic animals_ (Archezoa) form the first class in the series of
-Egg animals. It contains only the most simple and most ancient primary
-forms of the animal kingdom, whose former existence we have proved by
-means of the fundamental law of biogenesis; they are, (1) Animal Monera;
-(2) Animal Amoebæ; (3) Animal Synamoebæ. We may, if we choose, include
-among them a portion of the still living Monera and Amoebæ, but another
-portion (according to the discussion in Chapter XVI.) must on account of
-their neutral nature be considered as Protista, and a third portion, on
-account of their vegetable nature, must be considered as plants.
-
-A second class of the egg animals consists of the _Gregarines_
-(Gregarinæ), which live as parasites in the intestines and body-cavities
-of many animals. Some of these Gregarines are perfectly simple cells
-like the Amoebæ; some form chains of two or three identical cells, one
-lying behind the other. They differ from the naked Amoebæ by possessing
-a thick, simple membrane, which surrounds their cell-body; they can be
-considered as animal Amoebæ which have adopted a parasitical mode of
-life, and in consequence have surrounded themselves with a secreted
-covering.
-
-As a third class of egg animals, we adopt the real _Infusoria_
-(Infusoria), embracing those forms to which modern zoology almost
-universally limits this class of animals. The principal portion of them
-consists of the small _ciliated Infusoria_ (Ciliata), which inhabit all
-the fresh and salt waters of the earth in great numbers, and which swim
-about by means of a delicate garb of vibratile fringes. A second and
-smaller division consists of the adherent _sucking Infusoria_ (Acinetæ),
-which take their food by means of fine sucking-tubes. Although during
-the last thirty years numerous and very careful investigations have been
-made on these small animalcules,--which are mostly invisible to the
-naked eye,--still we are even now not very sure about their development
-and form-value. We do not even yet know whether the Infusoria are single
-or many-celled; but as no investigator has as yet proved their body to
-be a combination of cells, we are, in the mean time, justified in
-considering them as single-celled, like the Gregarines and the Amoebæ.
-
-The second main class of primæval animals consists of the _Germ animals_
-(Blastularia). This name we give to those extinct Protozoa which
-correspond to the two ontogenetic embryonic forms of the six higher
-animal tribes, namely, the Planula and the Gastrula. The body of these
-Blastularia, in a perfectly developed state, was composed of many cells,
-and these cells moreover differentiated--in two ways at least--into an
-external (animal or dermal) and an internal (vegetative or gastral)
-mass. Whether there still exist representatives of this group is
-uncertain. Their former existence is undoubtedly proved by the two
-exceedingly important ontogenetic animal forms which we have already
-described as Planula and Gastrula, and which still occur as a transient
-stage of development in the ontogeny of the most different tribes of
-animals. Corresponding to these, we may, according to the biogenetic
-principle, assume the former existence of two distinct classes of
-Blastularia, namely, the _Planæada_ and _Gastræada_. The type of the
-_Planæada_ is the _Planæa_--long since extinct--but whose historical
-portrait is still presented to us at the present day in the widely
-distributed _ciliated larva_ (Planula). (Frontispiece, Fig. 4.) The type
-of the _Gastræada_ is the _Gastræa_, of whose original nature the
-mouth-and-stomach larva (Gastrula), which recurs in the most different
-animal tribes, still gives a faithful representation. (Frontispiece Fig.
-5, 6.) Out of the Gastræa, as we have previously mentioned, there were
-at one time developed two different primary forms, the Protascus and
-Prothelmis; the former must be looked upon as the primary form of the
-Zoophytes, the latter as the primary form of Worms. (Compare the
-enunciation of this hypothesis in my Monograph of the Calcareous
-Sponges, vol i. p. 464.)
-
-The _Animal-plants_ (Zoophyta, or Coelenterata) which constitute the
-second tribe of the animal kingdom, rise considerably above the
-primitive animals in the characters of their whole organisation, while
-they remain far below most of the higher animals. For in the latter
-(with the exception only of the lowest forms) the four distinct
-functions of nutrition--namely, digestion, circulation of the blood,
-respiration, and excretion--are universally accomplished by four
-perfectly different systems of organs: by the intestines, the vascular
-system, the organs of respiration, and the urinary apparatus. In
-Zoophytes, however, these functions and their organs are not yet
-separate, and are all performed by a single system of alimentary canals,
-by the so-called gastro-vascular system, or the coelenteric apparatus of
-the intestinal cavity. The mouth, which is also the anus, leads into a
-stomach, into which the other cavities of the body also open. In
-Zoophytes the body-cavity, or "coeloma," possessed by the four higher
-tribes of animals is still completely wanting, likewise the vascular
-system and blood, as also the organs of respiration, etc.
-
-All Zoophytes live in water; most of them in the sea, only a very few in
-fresh water, such as fresh-water sponges (Spongilla) and some primæval
-polyps (Hydra, Cordylophora). A specimen of the pretty flower-like forms
-which are met with in great variety among Zoophytes is given on Plate
-VII. (Compare its explanation in the Appendix.)
-
-The tribe of animal-plants, or Zoophytes, is divided into two distinct
-provinces, the _Sponges_, or _Spongiæ_, and the _Sea-nettles_, or
-_Acalephæ_ (p. 144). The latter are much richer in forms and more highly
-organized than the former. In all Sponges the entire body, as well as
-the individual organs, are differentiated and perfected to a much less
-extent than in Sea-nettles. All Sponges lack the characteristic
-_nettle-organs_ which all Sea-nettles possess.
-
-The common primary form of all Zoophytes must be looked for in the
-_Protascus_, an animal form long since extinct, but whose existence is
-proved according to the biogenetic principle by the Ascula. This Ascula
-is an ontogenetical development form which, in Sponges as well as in
-Sea-nettles, proceeds from the Gastrula. (Compare the Ascula of the
-calcareous sponge on the Frontispiece, Fig. 7, 8.) For after the
-Gastrula of zoophytes has for a time swum about in the water it sinks to
-the bottom, and there adheres by that pole of its axis which is opposite
-to the opening of the mouth. The external cells of the ectoderm draw in
-their vibrating, ciliary hairs, whereas, on the contrary, the inner
-cells of the entoderm begin to form them. Thus the Ascula, as we call
-this changed form of larva, is a simple sack, its cavity (the cavity of
-the stomach or intestine) opening by a mouth externally, at the upper
-pole of the longitudinal axis (opposite the basal point of fixture). The
-entire body is here in a certain sense a mere stomach or intestinal
-canal, as in the case of the Gastrula. The wall of the sack, which is
-both body wall and intestinal wall, consists of two layers or coats of
-cells, a fringed _entoderm_, or gastral layer (corresponding with the
-inner or vegetative germ-layer of the higher animals), and an unfringed
-exoderm or dermal layer (corresponding with the external or animal
-germ-layer of the higher animals). The original _Protascus_, a true
-likeness of which is still furnished by the Ascula, probably formed
-egg-cells and sperm-cells out of its gastral layer.
-
-The Protascads--as we will call the most ancient group of vegetable
-animals, represented by the Protascus-type--divided into two lines or
-branches, the Spongiæ and the Sea-nettles, or Acalephæ. I have shown in
-my Monograph of the Calcareous Sponges (vol. i. p. 485) how closely
-these two main classes of Zoophytes are related, and how they must both
-be derived, as two diverging forms, from the Protascus-form. The primary
-form of Spongiæ, which I have there called Archispongia, arose out of
-the Protascus by the formation of pores through its body-wall; the
-primary form of Sea-nettles, which I there called Archydra, developed
-out of the Protascus by the formation of nettle-organs, as also by the
-formation of feelers or tentacles.
-
-The main-class or branch of the _Sponges_, _Spongiæ_, or _Porifera_,
-lives in the sea, with the single exception of the green fresh-water
-Sponge (Spongilla). These animals were long considered as plants, later
-as Protista; in most Manuals they are still classed among the primæval
-animals, or Protozoa. But since I have demonstrated their development
-out of the Gastrula, and the construction of their bodies of two
-cellular germ-layers (as in all higher animals), their close
-relationship to Sea-nettles, and especially to the Hydrapolyps, seems
-finally to be established. The _Olynthus_ especially, which I consider
-as the common primary form of calcareous sponges, has thrown a complete
-and unmistakable light upon this point.
-
-The numerous forms comprised in the class of Spongiæ have as yet been
-but little examined; they may be divided into three legions and eight
-orders. The first legion consists of the soft, gelatinous _Mucous
-Sponges_ (Myxospongiæ), which are characterized by the absence of any
-hard skeleton. Among them are, on the one hand, the long-since-extinct
-primary forms of the whole class, the type of which I consider to be the
-Archispongia; on the other hand there are the still living, gelatinous
-sponges, of which the _Halisarca_ is best known. We can obtain a notion
-of the Archispongia, the most ancient primæval sponge, if we imagine the
-Olynthus (see Frontispiece), to be deprived of its radiating calcareous
-spiculæ.
-
-The second legion of Spongiæ contains the _Fibrous Sponges_
-(Fibrospongiæ), the soft body of which is supported by a firm, fibrous
-skeleton. This fibrous skeleton often consists merely of so-called
-"horny fibres," formed of a very elastic, not readily destructible,
-organic substance. This is the case for instance in our common bathing
-Sponge (Euspongia officinalis), the purified skeleton of which we use
-every morning when washing. Blended with the horny, fibrous skeleton of
-many of these Sponges, there are numerous flinty spicula; this is the
-case for example with the fresh-water Sponge (Spongilla). In others the
-whole skeleton consists of only calcareous or silicious spicula which
-are frequently interwoven into an extremely beautiful lattice-work, as
-in the celebrated Venus' Flower Basket (Euplectella). Three orders of
-fibrous sponges may be distinguished according to the different
-formation of the spicula, namely, Chalynthina, Geodina, and
-Hexactinella. The natural history of the fibrous sponges is of especial
-interest to the Theory of Descent, as was first shown by Oscar Schmidt,
-the greatest authority on this group of animals. In no other group,
-perhaps, can the unlimited pliability of the specific form, and its
-relation to Adaptation and Inheritance, be so clearly followed step by
-step; perhaps in no other group is the species so difficult to limit and
-define.
-
-[Illustration: Pl. VII.
-
-E. Haeckel del. Lagesse sc.]
-
-This proposition, which applies to the great legion of the Fibrous
-Sponges, applies in a still higher degree to the smaller but exceedingly
-interesting legion of the calcareous sponges (Calcispongiæ), on which in
-1872, after five years' careful examination, I published a comprehensive
-Monograph. The sixty plates of figures accompanying this Monograph
-explain the extreme pliability of these small sponges "good species" of
-which, in fact, cannot be spoken of in the usual systematic sense. We
-find among them only varying series of forms, which do not even
-completely transmit their specific form to their nearest descendants,
-but by adaptation to subordinate, external conditions of existence,
-perpetually change. It frequently occurs here, that there arise out of
-one and the same stock different form-species, which according to the
-usual system would belong to several quite distinct genera; this is the
-case, for instance, with the remarkable Ascometra (Frontispiece, Fig.
-10.) The entire external bodily form is much more pliable and protean in
-Calcareous Sponges than in the silicious sponges, which are
-characterized by possessing silicious spicula, forming a beautiful
-skeleton. Through the study of the comparative anatomy and ontogeny of
-calcareous sponges, we can recognise, with the greatest certainty, the
-common primary form of the whole group, namely, the sack-shaped
-_Olynthus_, whose development is represented in the Frontispiece
-(compare its explanation in the Appendix). Out of the Olynthus (Fig. 9
-on the Frontispiece), the order of the Ascones was the first to develop,
-out of which, at a later period, the two other orders of Calcareous
-Sponges, the _Leucones_ and _Sycones_, arose as diverging branches.
-Within these orders, the descent of the individual forms can again be
-followed step by step. Thus the Calcareous Sponges in every respect
-confirm the proposition which I have elsewhere maintained: that "the
-natural history of sponges forms a connected and striking argument in
-favour of Darwin."
-
-The second main class or branch in the tribe of Zoophytes is formed by
-the Sea-nettles (Acalephæ, or Cnidæ). This interesting group of animals,
-so rich in forms, is composed of three different classes, namely, the
-Hood-jellies (Hydromedusæ), the Comb-jellies (Ctenophora), and the
-Corals (Coralla). The hypothetical, extinct Archydra must be looked upon
-as the common primary form of the whole group; it has left two near
-relations in the still living fresh-water polyps (Hydra and
-Cordylophora). The Archydra was very closely related to the simplest
-forms of Spongiæ (Archispongia and Olynthus), and probably differed from
-them only by possessing nettle organs, and by the absence of cutaneous
-pores. Out of the Archydra there first developed the different Hydroid
-polyps, some of which became the primary forms of Corals, others the
-primary forms of Hydromedusæ. The Ctenophora developed later out of a
-branch of the latter.
-
-The Sea-nettles differ from the Spongiæ (with which they agree in the
-characteristic formation of the system of the alimentary canal)
-principally by the constant possession of nettle organs. These are small
-bladders filled with poison, large numbers--generally millions--of which
-are dispersed over the skin of the sea nettles, and which burst and
-empty their contents when touched. Small animals are killed by this; in
-larger animals this nettle poison causes a slight inflammation of the
-skin, just as does the poison of our common nettles. Any one who has
-often bathed in the sea, will probably have at times come in contact
-with large Hood-jellies (Jelly-fish), and become acquainted with the
-unpleasant burning feeling which their nettle organs can produce. The
-poison in the splendid blue Jelly-fish, Physalia, or Portuguese
-Man-of-war, acts so powerfully that it may lead to the death of a human
-being.
-
-The class of Corals (Coralla) lives exclusively in the sea, and is more
-especially represented in the warm seas by an abundance of beautiful and
-highly-coloured forms like flowers. Hence they are also called
-_Flower-animals_ (Anthozoa). Most of them are attached to the bottom of
-the sea, and contain an internal calcareous skeleton. Many of them by
-continued growth produce such immense stocks that their calcareous
-skeletons have formed the foundation of whole islands, as is the case
-with the celebrated coral reefs and atolls of the South Seas, the
-remarkable forms of which were first explained by Darwin.(13) In corals
-the counterparts, or antimera--that is, the corresponding divisions of
-the body which radiate from and surround the central main axis of the
-body--exist sometimes to the number of four, sometimes to the number of
-six or eight. According to this we distinguish three legions, the
-Fourfold (Tetracoralla), Sixfold (Hexacoralla), and Eightfold corals
-(Octocoralla). The fourfold corals form the common primary group of the
-class, out of which the sixfold and eightfold have developed as two
-diverging branches.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 4 Classes and 30 Orders of the Animal Plants, or Zoophytes._
-
- ----------------+--------------------+--------------------+---------------
-  _Class of the_ | _Legions of the_   | _Orders of the_    | _A Genus Name_
-  _Zoophytes._   |  _Zoophytes._      | _Zoophytes._       |  _as example._
- ----------------+--------------------+--------------------+---------------
-        I.        { I. Myxospongiæ      { 1. Archispongina | Archispongia
-                  { _Mucous Sponges_    { 2. Halisarcina   | Halisarca
-    =Sponges=     {                                        |
-                  { II. Fibrospongiæ    { 3. Chalynthina   | Spongilla
-    +Spongiæ+     {_Fibrous Sponges_    { 4. Geodina       | Ancorina
-        or        {                     { 5. Hexactinella  | Euplectella
-    +Porifera+    {                                        |
-                  { III. Calcispongiæ   { 6. Ascones       | Olynthus
-                  {_Calcareous Sponges_ { 7. Leucones      | Dyssycus
-                  {                     { 8. Sycones       | Sycurus
-                                                           |
-                                                           |
-       II.        { IV. Tetracoralla    { 9. Rugosa        | Cyathophyllum
-                  {_Fourfold Corals_    { 10. Paranemeta   | Cereanthus
-    =Corals=      {                                        |
-                  { V. Hexacoralla      { 11. Cauliculata  | Antipathes
-    +Coralla+     {_Sixfold Corals_     { 12. Madreporaria | Astræa
-        or        {                     { 13. Halirhoda    | Actinia
-    +Anthozoa+    {                                        |
-                  { VI. Octocoralla     { 14. Alcyonida    | Lobularia
-                  {_Eightfold Corals_   { 15. Gorgonida    | Isis
-                  {                     { 16. Pennatulida  | Veretillum
-                                                           |
-                                                           |
-      III.        { VII. Archydræ       } 17. Hydraria     | Hydra
-                  {_Primæval Polyps_    }                  |
-  =Jelly-polyps=  {                                        |
-                  { VIII. Leptomedusæ   { 18. Vesiculata   | Sertularia
-   +Hydromedusæ+  {_Soft Jelly-fish_    { 19. Ocellata     | Tubularia
-                  {                     { 20. Siphonophora | Physophora
-        or        {                                        |
-                  { IX. Trachymedusæ    { 21. Marsiporchida| Trachynema
-  =Hood-jellies=  { _Hard Jelly-fish_   { 22. Phyllorchida | Geryonia
-                  {                     { 23. Elasmorchida | Charybdæ
-     +Medusa+     {                                        |
-                  { X. Calycozoa        } 24. Podactinaria | Lucernaria
-                  { _Stalked Jellies_   }                  |
-                  {                                        |
-                  { XI. Discomedusæ     { 25. Semæostomeæ  | Aurelia
-                  { _Disc-jellies_      { 26. Rhizostomeæ  | Crambessa
-                                                           |
-                                                           |
-       IV.        { XII. Eurystoma      } 27. Beroida      | Beroe
-                  { _Wide-mouthed_      }                  |
-  =Comb-jellies=  {                                        |
-                  { XIII. Stenostoma    { 28. Saccata      | Cydippe
-   +Ctenophora+   { _Narrow-mouthed_    { 29. Lobata       | Eucharis
-                  {                     { 30. Tæniata      | Cestum
-
-        ----------------------------------------------------------------
-
-                 Ctenophora                      Hydromedusæ
-             Tæniata   Lobata                    Rhizostomeæ
-                 |        |                           |
-                 |        |                           |
-                 \---v----/                      Semæostomeæ
-                  Saccata                        DISCOMEDUSÆ
-                STENOSTOMA                            |
-                     |      Trachymedusæ              |   Siphonophora
-                     |            |                   |         |
-                     |            |   Lucernaria      |         |
-                EURYSTOMA>        |   Calycozoa       |         |
-                     |            |       |           |         |
-                     |            |       |           |         |
-                     \-------------------------v----------------/
-                                           LEPTOMEDUSÆ
-                              Coralla          |
-                                   Octocoralla |
-                         Hexacoralla    |      |
-                              |         |      |
-                              |         |      |
-                              \----v----/      |
-                               Tetracoralla    |
-                Spongiæ                 |      |
-        Fibrospongiæ     Calcispongiæ   |      |
-         Chalynthina   Leucones  Sycones|      |
-              |           |        |    |      |
-              |           |        |    |      |
-              |           |        |    |      |
-  Hexactinella|Geodina Dyssycus Sycurus |    Hydroida
-       |      |   |       |        |    |      | Cordylophora
-       |      |   |       |        |    |      |     |     Hydra
-       \------v---/       \-----v--/    |      |     |       |
-              |              Ascones    |      |     |       |
-              |  Myxospongia    |       |      \-----v-------/
-              |  Halisarcina    |       |         HYDROIDA
-              |      |          |   Procorallum        |
-              |      |          |       |              |
-         CHALYNTHUS  |       OLYNTHUS   |              |
-              |      |          |       \-----v--------/
-              \------v----------/        Hydroida
-                Archispongiæ                 |
-                     |                       |
-                     |                    Archydra
-                     |                       |
-                     \--------------v--------/
-                                Protascus
-                                    |
-                                 Gastræa
-
-The second class of Sea-nettles is formed by the _Hood-jellies_ (Medusæ)
-or _Polyp-jellies_ (Hydromedusæ). While most corals form stocks like
-plants, and are attached to the bottom of the sea, the Hood-jellies
-generally swim about freely in the form of gelatinous bells. There are,
-however, numbers of them, especially the lower forms, which adhere to
-the bottom of the sea, and resemble pretty little trees. The lowest and
-simplest members of this class are the little fresh-water polyps (Hydra
-and Cordylophora). We may look upon them as but little changed
-descendants of those _Primæval polyps_ (Archydræ), from which, during
-the primordial period, the whole division of the Sea-nettles originated.
-Scarcely distinguishable from the Hydra are the adherent Hydroid polyps
-(Campanularia, Tubularia), which produce freely swimming medusæ by
-budding, and out of the eggs of these there again arise adherent polyps.
-These freely swimming Hood-jellies are mostly of the form of a mushroom,
-or of an umbrella, from the rim of which many long and delicate
-tentacles hang. They are among the most beautiful and most interesting
-inhabitants of the sea. The remarkable history of their lives, and
-especially the complicated alternation of generation of polyps and
-medusæ, are among the strongest proofs of the truth of the theory of
-descent. For just as Medusæ still daily arise out of the Hydroids, did
-the freely swimming medusa-form originally proceed, phylogenetically,
-out of the adherent polyp-form. Equally important for the theory of
-descent is the remarkable _division of labour_ of the individuals, which
-among some of them is developed to an astonishingly high degree, more
-especially in the splendid _Siphonophora_.(37) (Plate VII. Fig. 13.)
-
-The third class of Sea-nettles--the peculiar division of Comb-jellies
-(Ctenophora), probably developed out of a branch of the Hood-jellies.
-The Ctenophora, which are also called Ribbed-jellies, possess a body of
-the form of a cucumber, which, like the body of most Hood-jellies, is as
-clear and transparent as crystal or cut glass. Comb or Ribbed-jellies
-are characterized by their peculiar organs of motion, namely, by eight
-rows of paddling, ciliated leaflets, which run in the form of eight ribs
-from one end of the longitudinal axis (from the mouth) to the opposite
-end. Those with narrow mouths (Stenostoma) probably developed later out
-of those with wide mouths (Eurystoma). (Compare Plate VII. Fig. 16.)
-
-The third tribe of the animal kingdom, the phylum of _Worms_ or
-worm-like animals (Vermes, or Helminthes), contains a number of
-diverging branches. Some of these numerous branches have developed into
-well-marked and perfectly independent classes of Worms, but others
-changed long since into the original, radical forms of the four higher
-tribes of animals. Each of these four higher tribes (and likewise the
-tribe of Zoophytes) we may picture to ourselves in the form of a lofty
-tree, whose branches represent the different classes, orders, families,
-etc. The phylum of Worms, on the other hand, we have to conceive as a
-low bush or shrub, out of whose root a mass of independent branches
-shoot up in different directions. From this densely branched shrub, most
-of the branches of which are dead, there rise four high stems with many
-branches. These are the four lofty trees just mentioned as representing
-the higher phyla--the Echinoderma, Articulata, Mollusca, and Vertebrata.
-These four stems are directly connected with one another at the root
-only, to wit, by the common primary group of the Worm tribe.
-
-The extraordinary difficulties which the systematic arrangement of Worms
-presents, for this reason merely, are still more increased by the fact
-that we do not possess any fossil remains of them. Most of the Worms had
-and still have such soft bodies that they could not leave any
-characteristic traces in the neptunic strata of the earth. Hence in this
-case again we are entirely confined to the records of creation furnished
-by ontogeny and comparative anatomy. In making then the exceedingly
-difficult attempt to throw a few hypothetical rays of light upon the
-obscurity of the pedigree of Worms, I must therefore expressly remark
-that this sketch, like all similar attempts possesses only a provisional
-value.
-
-The numerous classes distinguished in the tribe of Worms, and which
-almost every zoologist groups and defines according to his own personal
-views, are, in the first place, divided into two essentially different
-groups or branches, which in my Monograph of the Calcareous Sponges I
-have termed Acoelomi and Coelomati. For all the lower Worms which are
-comprised in the class of Flat-worms (Platyhelminthes), (the
-Gliding-worms, Sucker-worms, Tape-worms), differ very strikingly from
-other Worms, in the fact that they possess neither blood nor body-cavity
-(no coelome); they are, therefore, called Acoelomi. The true cavity, or
-coelome, is completely absent in them as in all the Zoophytes; in this
-important respect the two groups are directly allied. But _all other
-Worms_ (like the four higher tribes of animals) possess a genuine
-body-cavity and a vascular system connected with it, which is filled
-with blood; hence we class them together as _Coelomati_.
-
-The main division of _Bloodless Worms_ (Acoelomi) contains, according to
-our phylogenetic views, besides the still living Flat-worms, the unknown
-and extinct primary forms of the whole tribe of Worms, which we shall
-call the Primæval Worms (Archelminthes). The type of these _Primæval
-Worms_, the ancient Prothelmis, may be directly derived from the Gastræa
-(p. 133). Even at present the Gastrula-form--the faithful historical
-portrait of the Gastræa--recurs in the ontogenesis of the most different
-kinds of worms as a transient larva-form. The ciliated Gliding-worms
-(Turbellaria), the primary group of the present Planary or Flat-worms
-(Platyhelminthes), are the nearest akin to the Primæval Worms. The
-parasitical Sucker-worms (Trematoda) arose out of the Gliding-worms,
-which live freely in water, by adaptation to a parasitical mode of life;
-and out of them later on--by an increasing parasitism--arose the
-Tape-worms (Cestoda).
-
-Out of a branch of the Acoelomi arose the second main division of the
-Worm tribe, the Worms with blood and body-cavity (Coelomati): of these
-there are seven different classes.
-
-The Pedigree on p. 151 shows how the obscure phylogeny of the seven
-classes of Coelomati may be supposed to stand. We shall, however,
-mention these classes here quite briefly, as their relationships and
-derivation are, at present, still very complicated and obscure. More
-numerous and more accurate investigations of the ontogeny of the
-different Coelomati will at some future time throw light upon their
-phylogenesis.
-
-The Round Worms (Nemathelminthes) which we mention as the first class of
-the Coelomati, and which are characterized by their cylindrical form,
-consist principally of parasitical Worms which live in the interior of
-other animals. Of human parasites, the celebrated Trichinæ, the
-Maw-worms, Whip-worms, etc., for example, belong to them. The Star-worms
-(Gephyrea) which live exclusively in the sea are allied to round worms,
-and the comprehensive class of Ring-worms (Annelida) are allied to the
-former. To the Ring-worms, whose long body is composed of a number of
-segments, all alike in structure, belong the Leeches (Hirudinea),
-Earth-worms (Lumbricina), and all the marine bristle-footed Worms
-(Chætopoda). Nearly akin to them are the Snout-worms (Rhynchocoela), and
-the small microscopic Wheel-worms (Rotifera). The unknown, extinct,
-primary forms of the tribe of Sea-stars (Echinoderma), and of the tribe
-of the articulated animals (Arthropoda), were nearest akin to the
-Ring-worms. On the other hand, we must probably look for the primary
-forms of the great tribe of Molluscs in extinct Worms, which were very
-closely related to the Moss-polyps (Bryozoa) of the present day; and for
-the primary forms of the Vertebrata in the unknown Coelomati, whose
-nearest kin of the present day are the Sea-sacs, especially the Ascidia.
-
-SYSTEMATIC SURVEY
-
-_Of the 8 Classes and 22 Orders of the Worm Tribe._
-
-(Compare Gen. Morph. ii. Plate V. pp. 75-77.)
-
-
-  ------------------+-------------------------+----------------------+------------------
-  _Classes_         |                         |  _Systematic_        |
-  _of the_          |  _Orders of the_        |  _Name of the_       | _Name of a Genus_
-  _Worm Tribe._     |   _Worm Tribe._         | _Orders of Worms_.   |  _as example._
-                    |                         |                      |
-  ------------------+-------------------------+----------------------+------------------
-  1. _Flat_          {  1. Primæval worms     |  1. Archelminthes    | Prothelmis
-  _Worms_            {  2. Gliding-worms      |  2. Turbellaria      | Planaria
-  Platyhel-          {  3. Sucker-worms       |  3. Trematoda        | Distoma
-  minthes            {  4. Tape-worms         |  4. Cestoda          | Tænia
-                                              |                      |
-  2. _Round_         {  5. Arrow-worms        |  5. Chætognatha      | Sagitta
-  _Worms_            {  6. Thread-worms       |  6. Nematoda         | Trichina
-  Nemathel-          {  7. Hook-headed        |  7. Acanthocephala   | Echinorhynchus
-  minthes            {      worms             |                      |
-                                              |                      |
-  3. _Moss_          }  8. Horse-shoe-lipped  |  8. Lophopoda        | Alcyonella
-  _Polyps_           }  9. Circle-lipped      |  9. Stelmopoda       | Retepora
-  Bryozoa            }                        |                      |
-                                              |                      |
-  4. _Sea-sacs_      { 10. Sea-squirts        | 10. Ascidia          | Phallusia
-  Tunicata           { 11. Sea-barrels        | 11. Thaliacea        | Salpa
-                                              |                      |
-  5. _Proboscideans_ } 12. Tongue-worms       | 12. Enteropneusta    | Balanoglossus
-  Rhynchocoela       } 13. Cord-worms         | 13. Nemertina        | Borlasia
-                                              |                      |
-                     { 14. Star-worms without | 14. Sipunculida      | Sipunculus
-  6. _Star-Worms_    {       bristles         |                      |
-  Gephyrea           { 15. Star-worms with    | 15. Echiurida        | Echiurus
-                     {       bristles         |                      |
-                                              |                      |
-  7. _Wheel_         }                        |                      |
-  _Animalcule_       } 16. Wheel-worms        | 16. Rotatoria        | Hydatina
-  Rotifera           }                        |                      |
-                                              |                      |
-                     { 17. Bear-worms         | 17. Arctisca         | Macrobiotus
-                     { 18. Worms with claws   | 18. Onychophora      | Peripatus
-  8. _Ring_          { 19. Leeches            | 19. Hirudinea        | Hirudo
-  _Worms_            { 20. Land-worms         | 20. Drilomorpha      | Lumbricus
-  Annelida           { 21. Mailed worms       | 21. Phracthelminthes | Crossopodia
-                     { 22. Bristle-footed     | 22. Chætopoda        | Aphrodite
-                     {      worms             |                      |
-
-        ----------------------------------------------------------------
-
-                       Chætopoda
-                           |          Drilomorpha
-                           |               |
-                           \-------v-------/
-                                   |
-                  Phracthelminthes |
-                          |        |
-                 Echiurida|        |   Hirudinea
-        Sipunculida  |    |        |       |
-            |        |    |        |       |   Onychophora
-            \----v---/    |        |       |        |
-               +Gephyrea+ |        |       |        |  Arctisca
-                     |    |        |       |        |     |
-                     |    |        |       |        \--v---/
-      Chætognatha    |    \--v-----/       |           |
-           |         |       |             \-----v-----/
-  Nematoda |         |       |                   |
-     |     |         |       \---------v---------/
-     \--v--/         |              +Annelida+
-        |  Acantho-  |                   |
-        |   cephala  | Stelmopoda        |
-        |     |      |     |             |              Enteropneusta
-        \--v--/      |     |             |                   |
-   +Nemathelminthes+ | Lophopoda         |         Ascidia   |
-           |         |  +Bryozoa+        |  Thalicea |       |  Nemertina
-           |         |     |             |    |      |       |     |
-           |         |     | +Rotifera+  |    |      |       |     |
-           |         |     |    |        |    |      |       \---v-/
-           |         |     |    |        |    |      |    +Rhynchocoela+
-           |         |     |    |        |    \--v---/           |
-           |         |     |    \----v---/    +Tunicata+         |
-           |         |     |         |           |               |
-           \-----------------------v-----------------------------/
-                  +Coelomati+ (_worms with body-cavity_)
-                                   |
-             Cestoda               |
-                 |                 |
-                 |                 |
-             Trematoda             |
-                 |                 |
-                 |                 |
-           Turbellaria             |
-         +Platyhelminthes+         |
-                 |                 |
-                 |                 |
-                 \-------v---------/
-             +Acoelomi+ (_worms without body-cavity_)
-                         |
-                         |
-                   Archelminthes
-                    +Prothelmis+
-                         |
-                         |
-                      +Gastræa+
-
-
-The class of Sea-sacs (Tunicata) is one of the most remarkable among
-Worms. They all live in the ocean, where some of the Ascidiæ adhere to
-the bottom, while others (the sea-barrels, or Thaliacea) swim about
-freely. In all of them the non-jointed body has the form of a simple
-barrel-shaped sack, which is surrounded by a thick cartilaginous mantle.
-This mantle consists of the same non-nitrogenous combination of carbon,
-which, under the name of cellulose, plays an important part in the
-Vegetable Kingdom, and forms the largest portion of vegetable cellular
-membranes, and consequently also the greater part of wood. The
-barrel-shaped body generally possesses no external appendages. No one
-would recognise in them a trace of relationship to the highly
-differentiated vertebrate animals. And yet this can no longer be
-doubted, since Kowalewsky's investigations, which in the year 1867
-suddenly threw an exceedingly surprising and unmistakable light upon
-them. From these investigations it has become clear that the individual
-development of the adherent simple Ascidian Phallusia agrees in most
-points with that of the lowest vertebrate animal, namely, the Lancelet
-(Amphioxus lanceolatus). The early stages of the Ascidia possess the
-beginnings of the _spinal marrow_ and the _spinal column_ (chorda
-dorsalis) lying beneath it, which are the two most essential and most
-characteristic organs of the vertebrate animal. Accordingly, of all
-invertebrate animals known to us, the _Tunicates are without doubt the
-nearest blood relations of the Vertebrates_, and must be considered as
-the nearest relations of those Worms out of which the vertebrate tribe
-has developed. (Compare Plates XII. and XIII.)
-
-While thus different branches of the Coelomatous group of the Worms
-furnish us with several genealogical links leading to the four higher
-tribes of animals, and give us important phylogenetic indications of
-their origin, the lower group of Acoelomi, on the other hand, show close
-relationships to the Zoophytes, and to the Primæval animals. The great
-phylogenetic interest of the Worm tribe rests upon this peculiar
-intermediate position.
-
-
-
-
-CHAPTER XIX.
-
-PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-II. MOLLUSCA, STAR-FISHES, AND ARTICULATED ANIMALS.
-
-
-  Tribe of Molluscs.--Four Classes of Molluscs: Lamp-shells
-  (Spirobranchia); Mussels (Lamellibranchia); Snails (Cochlides);
-  Cuttle-fish (Cephalopoda).--Tribe of Star-fishes, or
-  Echinoderma.--Their Derivation from Ringed Worms (Mailed Worms,
-  or Phracthelminthes).--The Alternation of Generation in the
-  Echinoderma.--Four Classes of Star-fish: Sea-stars (Asteridea);
-  Sea-lilies (Crinoidea); Sea-urchins (Echinidea); Sea-cucumbers
-  (Holothuridea).--Tribe of Articulated Animals, or
-  Arthropoda.--Four Classes of Articulated Animals: Branchiata, or
-  Crustacea, breathing through gills; Jointed Crabs; Mailed
-  Crabs; Articulata Tracheata, breathing through Air
-  Tubes.--Spiders (Long Spiders, Round
-  Spiders).--Myriopods.--Insects.--Chewing and Sucking
-  Insects.--Pedigree and History of the Eight Orders of Insects.
-
-
-The great natural main groups of the animal kingdom, which we have
-distinguished as TRIBES, or PHYLA ("types" according to Bär and Cuvier),
-are not all of equal systematic importance for our phylogeny or history
-of the pedigree of the living world. They can neither be classed in a
-single series of stages, one above another, nor be considered as
-entirely independent stems, nor as equal branches of a single
-family-tree. It seems rather (as we saw in the last chapter) that the
-tribe of Protozoa, the so-called primæval animals, is the common radical
-group of the whole animal kingdom. Out of the Gastræada--which we class
-among the Protozoa--the Zoophytes and the Worms have developed, as two
-diverging branches. We must now in turn look upon the varied and
-much-branching tribe of Worms as the common primary group, out of which
-(from perfectly distinct branches) arose the remaining tribes, the four
-higher phyla of the animal kingdom. (Compare the Pedigree, p. 133.)
-
-Let us now take a genealogical look at these four higher tribes of
-animals, and try whether we cannot make out the most important outlines
-of their pedigree. Even should this attempt prove defective and
-imperfect, we shall at all events have made a beginning, and paved the
-road for subsequent and more satisfactory attempts.
-
-It does not matter in what succession we take up the examination of the
-four higher tribes. For these four phyla have no close relationship
-whatever among one another, but have grown out from entirely distinct
-branches of the group of Worms (p. 133). We may consider the tribe of
-Molluscs as the most imperfect and the lowest in point of morphological
-development. We nowhere meet among them with the characteristic
-articulation or segmented formation of the body, which distinguishes
-even the Ring-worms, and which in the other three higher tribes--the
-Echinoderma, Articulata, and Vertebrata--is most essentially connected
-with the high development of their forms, their differentiation, and
-perfection. The body in all Molluscs--in mussels, snails, etc.--is a
-simple non-jointed sack, in the cavity of which lie the intestines. The
-nervous system consists not of a cord but of several distinct (generally
-three) pairs of knots loosely connected with one another. For these and
-many other anatomical reasons, I consider the tribe of Molluscs (in
-spite of the high physiological development of its most perfect forms)
-to be morphologically the lowest among the four higher tribes of
-animals.
-
-Whilst, for reasons already given, we exclude the Moss-polyps, and
-Tunicates--which have hitherto been generally classed with the tribe of
-Molluscs--we retain as genuine Molluscs the following four classes:
-Lamp-shells, Mussels, Snails, and Cuttles. The two lower classes of
-Molluscs, the Lamp-shells and Mussels, possess neither head nor teeth,
-and they can therefore be comprised under one main class, or branch, as
-headless animals (Acephala), or toothless animals (Anodontoda). This
-branch is also frequently called that of the clam-shells (Conchifera, or
-Bivalvia), because all its members possess a two-valved calcareous
-shell. In contrast to these the two higher classes of Molluscs, the
-snails and cuttles, may be represented as a second branch with the name
-of Head-bearers (Cephalophora), or Tooth-bearers (Odontophora), because
-both head and teeth are developed in them.
-
-The soft, sack-shaped body in most Molluscs is protected by a calcareous
-shell or house, which in the Acephala (lamp-shells and mussels) consists
-of two valves, but in the Cephalophora (snails and cuttles) is generally
-a spiral tube (the so-called snail's house). Although these hard
-skeletons are found in large quantities in a petrified state in all the
-neptunic strata, yet they tell us but little of the historical
-development of the tribe, which must have taken place for the most part
-in the primordial period. Even in the Silurian strata we find fossil
-remains of all the four classes of Molluscs, one beside the other, and
-this, conjointly with much other evidence, distinctly proves that the
-tribe of Molluscs had then obtained a strong development, when the
-higher tribes, especially the Articulates and Vertebrates, had scarcely
-got beyond the beginning of their historical development. In subsequent
-periods, especially in the primary and secondary periods, these higher
-tribes increased in importance more and more at the expense of Molluscs
-and Worms, which were no match for them in the struggle for life, and
-accordingly decreased in number. The still living Molluscs and Worms
-must be considered as only a proportionately small remnant of the vast
-molluscan fauna, which greatly predominated in the primordial and
-primary periods over the other tribes. (Compare Plate VI. and
-explanation in the Appendix.)
-
-No tribe of animals shows more distinctly than do the Molluscs, how very
-different the value of fossils is in geology and in phylogeny. In
-geology the different species of the fossil shells of Molluscs are of
-the greatest importance because they serve as excellent marks whereby to
-characterize the different groups of strata, and to fix their relative
-ages. As far as relates to the genealogy of Molluscs, however, they are
-of very little value, because, on the one hand, the shells are parts of
-quite subordinate morphological importance, and because the actual
-development of the tribe belongs to the earlier primordial period, from
-which no distinct fossils have been preserved. If therefore we wish to
-construct the pedigree of Molluscs, we are mainly dependent upon the
-records of ontogeny and comparative anatomy from which we obtain
-something like the following result. (Gen. Morph. ii. Plate VI. pp.
-102-116.)
-
-The lowest stage of the four classes of genuine Molluscs known to us, is
-occupied by the Lamp-shells or Spiral-gills (Spirobranchia), frequently
-but inappropriately called Arm-footers (Brachiopoda), which have become
-attached to the bottom of the sea. There now exist but few forms of
-this class; for instance, some species of Lingula, Terebratula, and
-others akin to them, which are but feeble remnants of the great variety
-of forms which represented the Lamp-shells in earlier periods of the
-earth's history. In the Silurian period they constituted the principal
-portion of the whole Mollusc tribe. From the agreement which, in many
-respects, their early stage of development presents with the Moss
-animals, it has been concluded that they have developed out of Worms,
-which were nearly related to this class. Of the two sub-classes of
-Lamp-shells, the Hinge-less (Ecardines) must be looked upon as the lower
-and more imperfect, the Hinged (Testicardines) as the higher and more
-fully developed group.
-
-The anatomical difference between the Lamp-shells and the three other
-classes of Molluscs is so considerable that the latter may be
-distinguished from the former by the name of Otocardia. All the
-Otocardia have a heart with chamber (ventricle) and ante-chamber
-(auricle), whereas Lamp-shells do not possess the ante-chamber.
-Moreover, the central nervous system is developed only in the former
-(and not in the latter) in the shape of a complete pharyngeal ring.
-Hence the four classes of Molluscs may be grouped in the following
-manner:--
-
-
-                     {     1. Lamp-shells     }     I. Haplocardia
-  I.  Molluscs       {     (Spirobranchia).   }     (with simple heart).
-  without head.      {
-  _Acephala._        {     2. Mussels         }
-                     {     (Lamellibranchia). }     II. Otocardia
-                                              }     (with chamber
-  II.  Molluscs      {     3. Snails          }     and ante-chamber
-  with head.         {     (Cochlides).       }     to the heart).
-  _Cephalophora._    {     4. Cuttles         }
-                     {     (Cephalopoda).     }
-
-
-The result of these structural dispositions for the history of the
-pedigree of Molluscs, which is confirmed by palæontology, is that
-Lamp-shells stand much nearer to the primæval root of the whole tribe of
-Molluscs than do the Otocardia. Probably Mussels and Snails developed as
-two diverging branches out of Molluscs, which were nearly akin to the
-Lamp-shells.
-
-Mussels, or Plate-gills (Lamellibranchia), possess a bivalved shell like
-the Lamp-shells. In the latter, one of the two valves covers the back,
-the other the belly of the animal; whereas in Mussels the two valves lie
-symmetrically on the right and left side of the body. Most Mussels live
-in the sea, only a few in fresh water. The class is divided into two
-sub-classes, Asiphonia and Siphonida, of which the latter were developed
-at a later period out of the former. Among the Asiphonia are Oysters,
-mother-of-pearl Shells, and fresh water Mussels; among the Siphonida,
-which are characterized by a respiratory tube, are the Venus-shells,
-Razor-shells, and Burrowing Clams. The higher Molluscs seem to have
-developed at a later period out of those without head and teeth; they
-are distinguished from the latter by the distinct formation of the head,
-and more especially by a peculiar kind of tooth apparatus. Their tongue
-presents a curious plate, armed with a great number of teeth. In our
-common Vineyard Snail (Helix pomatia) the number of teeth amount to
-21,000, and in the large Garden Slug (Limax maximus) to 26,800.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 4 Classes, 8 Sub-classes, and 21 Orders of Molluscs._
-
-
-  ------------------+-----------------------+------------------------+-------------------
-    _Classes of_    |    _Sub-classes of_   |    _Orders of_         |  _Systematic Name_
-    _Molluscs._     |      _Molluscs._      |    _Molluscs._         |   _of the Orders._
-  ------------------+-----------------------+------------------------+-------------------
-          I. _Molluscs without head or teeth_: ACEPHALA _or_ ANODONTODA.
-  ---------------------------------------------------------------------------------------
-      I.            {   I. Ecardines        { 1. Stalked              1. Lingulida
-  =Lamp-shells=     {      _Hinge-less_     { 2. Flattened            2. Craniada
-                    {
-  +Spirobranchia+   {
-       or           {
-  +Brachiopoda+     {  II. Testicardines    { 3. Fleshy armed         3. Sarcobrachia
-                    {     _Hinge-less_      { 4. Calcareous-armed     4. Sclerobrachia
-
-
-      II.           { III. Asiphonia        { 5. One-muscled          5. Monomya
-    =Mussels=       { _Mussels without_     { 6. Uneven-muscled       6. Heteromya
-      or            { _respiratory tubes_   { 7. Even-muscled         7. Isomya
-  =Plate-gills=     {
-                    {
-  +Lamellibranchia+ {  IV. Siphonida        { 8. Round-mantled        8. Integripallia
-        or          {  _Mussels with_       { 9. Ray-mantled          9. Sinupalliata
-  +Phyllobranchia+  { _respiratory tubes_   { 10. Tube-mussels       10. Inclusa
-
-  ---------------------------------------------------------------------------------------
-          II. _Molluscs with head and teeth_: CEPHALOPHORA _or_ ODONTOPHORA.
-  ---------------------------------------------------------------------------------------
-
-                    {   V. Stump-headed     { 11. Tube-snails        11. Scaphopoda
-      III.          {      _Perocephala_    { 12. Butterfly-snails   12. Pteropoda
-     =Snails=       {
-                    {                       { 13. With hind gills    13. Opisthobranchia
-   +Cochlides+      {                       { 14. With fore gills    14. Prosobranchia
-       or           {   VI. Large-headed    { 15. Swimming-snails    15. Heteropoda
-  +Gasteropoda+     {      _Delocephala_    { 16. Beetle-snails      16. Chitonoida
-                    {                       { 17. Snails with lungs  17. Pulmonata
-
-
-                       VII. Chamber-Poulps  { 18. Pearl boats        18. Nautilida
-      IV.                  with four gills  { 19. Ammon's horns      19. Ammonitida
-    =Cuttles=       }     _Tetrabranchia_   {
-      or            }
-    =Poulps=        } VIII. Ink-Poulps with { 20. Ten-armed          20. Decabrachiones
-                    }       two gills       {
-  +Cephalopoda+     }       _Dibranchia_    { 21. Eight-armed        21. Octobrachiones
-
-        ----------------------------------------------------------------
-
-                                                      Dibranchia
-                         Heteropoda                        |
-                             |       _Prosobranchia_       |
-  _Pulmonata_                |              |         Tetrabranchia
-      |      Lipobranchia    |              |         Cephalopoda
-      |            |         |              |    (=Cuttles= or =Poulps=)
-      |     Gymnobranchia    |              |               |
-      |            |         \-------v------/               |
-      |            |                 |                      |
-      |     Pleurobranchia           |       Chitonides     |
-      |    _Opisthobranchia_         |            |         |
-      |            |                 |            |         |
-      \---------------------------------v---------/         |
-                                        |                   |
-                                   _Delocephala_            |
-                                        |                   |
-                                        |                   |
-                                        \--------v----------/
-                                                  |
-                                                  |       _Pteropoda_
-                        Inclusa                   |            |
-                           |                      |            |
-                           |                      \------v-----/
-                       Sinupalliata                      |
-                           |                  Scaphopoda |
-                           |                      |      |
-                     Integripalliata              \---v--/
-  Sclerobrachia       _Siphoniata_                    |
-        |                   |                   _Perocephala_
-        |                   |                     Cochlides
-        |                   |                     (=Snails=)
-   Sarcobrachia        _Asiphonia_                    |
-  _Testicardines_     Lamellibranchia                 |
-        |                (=Mussels=)                  |
-        |                    |                        |
-   _Ecardines_               \----------v-------------/
-  Spirobranchia                         |
-   (=Lamp-shells=)                     Otocardia
-        |            (Molluscs with chamber and ante-chamber
-        |                          to the heart)
-        |                                |
-        |                                |
-        \-----------------v--------------/
-                          |
-              Promollusca (Primæval Molluscs)
-                Molluscs with simple heart
-                          |
-                       (Worms)
-                          |
-                       Gastræa
-
-
-We distinguish two sub-classes among the Snails (Cochlides, or
-Gasteropoda), namely, the Stump-headed and the Large-headed Snails. The
-Stump-headed Snails (Perocephala) are very closely allied to Mussels
-(through the Tooth-shells), and also to the Cuttle-fish (through the
-Butterfly-snails). The more highly developed Snails, with large heads
-(Delocephala), can be divided into Snails with gills (Branchiata) and
-Snails with lungs (Pulmonata). Among the latter are the Land-snails, the
-only Molluscs which have left the water and become habituated to a life
-on land. The great majority of Snails live in the sea, only a few live
-in fresh water. Some River-snails in the tropics (the Ampullaria) are
-amphibious, living sometimes on land, sometimes in water, and at one
-time they breathe through gills, at another through lungs. They have
-both kinds of respiratory organs, like the Mud-fish and Gilled Newts
-among the Vertebrata.
-
-The fourth and last class, and at the same time the most highly
-developed class of Molluscs, is that of the Cuttles, or Poulps, also
-called Cephalopoda (foot attached to the head). They all live in the
-sea, and are distinguished from Snails by eight, ten, or more long arms,
-which surround the mouth in a circle. The Cuttles existing in our recent
-oceans--the Sepia, Calamary, Argonaut, and Pearly Nautilus--are, like
-the few Spiral-gill Lamp-shells of the present time, but a poor remnant
-of the host which represents this class in the oceans of the primordial,
-primary, and secondary periods. The numerous fossil "Ammon's horns"
-(Ammonites), "pearl boats" (Nautilus), and "thunderbolts" (Belemnites)
-are evidences of the long since extinct splendour of the tribe. The
-Poulps, or Cuttles, have probably developed out of a low branch of the
-snail class, out of the Butterfly-snails (Pteropoda) or kindred forms.
-
-The different sub-classes and orders, distinguished in the four classes
-of Molluscs, whose systematic succession is given on the Table (p.
-160), furnish various proofs of the validity of the law of progress by
-their historical development and by the systematic development
-corresponding to it. As however these subordinate groups of Molluscs are
-in themselves of no further special interest, I must refer to the sketch
-of their pedigree on p. 161, and to the detailed pedigree of Molluscs
-which I have given in my General Morphology, and I shall now at once
-turn to the consideration of the tribe of Star-fishes.
-
-The Star-fishes (Echinoderma, or Estrellæ) among which are the four
-classes of Sea-stars, Sea-lilies, Sea-urchins, and Sea-cucumbers are one
-of the most interesting divisions of the animal kingdom, and yet we know
-less about them than about any. They all live in the sea. Every one who
-has been at the sea shore must have seen at least two of their forms,
-the Sea-stars and the Sea-urchins. The tribe of Star-fishes must be
-considered as a completely independent tribe of the animal kingdom on
-account of its very peculiar organization, and must be carefully
-distinguished from the Animal-plants--Zoophytes, or Coelenterata, with
-which it is still frequently but erroneously classed under the name
-Radiata (as for example, by Agassiz, who even to this day defends this
-error of Cuvier's, together with many others).
-
-All Echinoderma are characterized, and at the same time distinguished
-from all other animals, by a very remarkable apparatus for locomotion,
-which consists of a complicated system of canals or tubes, filled with
-sea water from without. The sea water in these aqueducts is moved partly
-by the strokes of the cilia, or vibratile hairs lining their walls, and
-partly by the contractions of the muscular walls of the tubes
-themselves, which resemble india-rubber bags. The water is pressed from
-the tubes into a number of little hollow feet, which thereby become
-widely distended, and are then employed for walking and suction. The
-Sea-stars are moreover characterized by a peculiar calcareous formation
-in the skin, which in most cases forms a firm, well-closed coat of mail,
-composed of a number of plates. In almost all Echinoderma the body
-consists of five radii (counterparts, or antimera) standing round the
-main axis of the body, where they meet. It is only in some species of
-Sea-stars that the number of these radii amount to more than five--to
-6-9, 10-12, or even to 20-40; and in this case the number of radii is
-generally not constant, but varies in different individuals of one
-species.
-
-The historical development and the pedigree of the Echinoderma are
-completely revealed to us by their numerous and, in most cases,
-excellently preserved fossil remains, by their very remarkable
-individual developmental history, and by their interesting comparative
-anatomy; this is the case with no other tribe of animals, even the
-Vertebrata themselves are not to be excepted. By a critical use of those
-three archives, and by a careful comparison of the results derived from
-their study, we obtain the following genealogy of the Star-fishes, which
-I have already published in my General Morphology (vol. ii. Plate IV.
-pp. 62-77.)
-
-The most ancient and original group of the Star-fishes, the primary form
-of the whole phylum, consists of the class of the true Sea-stars
-(Asterida). This is established by numerous and important arguments in
-anatomy and the history of development, but above all by the irregular
-and varying number of the radii, or antimera, which in all other
-Echinoderma is limited, without exception, to five. Every Star-fish
-consists of a central, small, body-disc, all round the circumference of
-which are attached five or several long articulated arms. _Each arm of
-the Star-fish essentially corresponds in its organisation with an
-articulated worm_ of the class of Ring-worms, or Annelida (p. 149). I
-therefore consider the Star-fish as a genuine _stock or cormus of five
-or more articulated worms_, which have arisen by the star-wise growth of
-a number of buds out of a central mother-worm. The connected members,
-thus grouped like the rays of a star, have inherited from the
-mother-worm the common opening of the mouth, and the common digestive
-cavity (stomach) lying in the central body-disc. The end by which they
-have grown together, and which fuses in the common central disc,
-probably corresponds to the posterior end of the original independent
-worms.
-
-In exactly the same way several individuals of certain kinds of worms
-are united so as to form a star-like cormus. This is the case in the
-_Botryllidæ_, compound Ascidians, belonging to the class of the
-Tunicata. Here also the posterior ends of the individual worms have
-grown together, and have formed a common outlet for discharges, a
-central cloaca; whereas at the anterior end each worm still possesses
-its own mouth. In Star-fishes the original mouths have probably become
-closed in the course of the historical development of the cormus, or
-colony, whereas the cloaca has developed into a common mouth for the
-whole cormus.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 4 Classes, 9 Sub-classes, and 20 Orders of Star-fishes._
-
-(Compare Gen. Morph. II. Plate IV. pp. 62-67.)
-
-
-  ----------------+-------------------------+---------------------------+------------------
-  _Classes of the | _Sub-classes of the     |    _Orders of the         | _Systematic Name
-  Star-fishes._   | Star-fishes._           |      Star-fishes._        |  of the Orders._
-  ----------------+-------------------------+---------------------------+------------------
-                                                                        |
-                   { I.                      { 1. Primary Stars         | 1. Tecastra
-                   { Sea Stars with radiated { 2. Articulated Stars     | 2. Colastra
-  I.               { stomach                 { 3. Brisinga Stars        | 3. Brisingastra
-  =Sea Stars=      { _Actinogastra_                                     |
-  +Asterida+       {
-                   { II.                     { 4. Serpent Stars         | 4. Ophiastra
-                   { Sea Stars with disc-    { 5. Tree Stars            | 5. Phytastra
-                   { shaped stomach          { 6. Lily Stars            | 6. Crinastra
-                   { _Discogastra_           {                          |
-                                                                        |
-                   { III.                    { 7. Plated Lilies with    | 7. Phatnocrinida
-                   { Lilies with arms        {      arms                |
-                   { _Brachiata_             { 8. Articulated Lilies    | 8. Colocrinida
-                   {                         {      with arms           |
-                                                                        |
-  II.              { IV.                     { 9. Regularly budding     | 9. Pentremitida
-  =Sea Lilies=     { Lilies with buds        {      Lilies              |
-  +Crinoida+       { _Blastoidea_            { 10. Lilies budding on    | 10. Eleutherocrina
-                   {                         {      two sides           |
-                                                                        |
-                   { V.                      { 11. Bladder Lilies       | 11. Agelacrinida
-                   { Bladder Lilies          {       without stalks     |
-                   { _Cystidea_              { 12. Bladder Lilies       | 12. Sphæronitida
-                                             {       with stalks        |
-                                                                        |
-                   { VI.                     { 13. Palechinida with     | 13. Melonitida
-                   { Older Sea Urchins       {       more than 10       |
-                   { (with more than         {       rows of ambulacral |
-                   { 20 rows of plates)      {        plates            |
-  III.             { _Palechinida_           { 14. Palechinida with     | 14. Eocidaria
-  =Sea Urchins=    {                         {       10 rows of         |
-  +Echinida+       { VII.                    {       ambulacral plates  |
-                   { More recent Sea         { 15. Autechinida with     | 15. Desmosticha
-                   { Urchins (with 20        {      band-like ambulacra |
-                   { rows of plates)         { 16. Autechnidia with     | 16. Petalosticha
-                   { _Autechinida_           {      leaf-like ambulacra |
-                                                                        |
-                   { VIII.                   { 17. Eupodia with scuti-  | 17. Aspidochirota
-                   { Sea Cucumbers           {       form tentacles     |
-                   { with aquatic feet       { 18. Eupodia with         | 18. Dendrochirota
-  IV.              { _Eupodia_               {      branching tentacles |
-  =Sea Cucumbers=  {                         {                          |
-                   { IX.                     {                          |
-  +Holothuriæ+     { Sea Cucumbers           { 19. Apodia with water-   | 19. Liodermatida
-                   { without aquatic         {       lungs              |
-                   { feet                    { 20. Apodia without       | 20. Synaptida
-                   { _Apodia_                {       water-lungs        |
-
-             ----------------------------------------------------------------
-
-                                                                    Clypeastridæ
-                                                                         |
-                                                      Spatangidæ         |
-                                                           |             |
-                                              Dysasteridæ  |             |
-                                                   |       |             |
-                             Aspidochirota         |       |             |
-                                   |               |       \------v------/
-         Synaptida                 |               |              |
-             |                     |               |         Cassidulidæ
-             |                     |               |        +Petalosticha+
-             |                     |               |              |
-             |                     |               |              |
-        Liodermatida               |               |              |
-          +Apodia+                 |               \------v-------/     Echinonidæ
-             |                     |                      |                 |
-             |                     |                 Galeritidæ             |
-             |                     |                      |   Echinometridæ |
-             \---------v-----------/                      |         |       |
-                       |                                  \------v---------/
-                 Dendrochirota                                   |
-                   +Eupodia+                                Latistellæ
-                  +Holothuriæ+            Salenidæ               |
-                \------v------/              |                   |
-                       |                     |                   |
-                       |                     \------v------------/
-                       |                            |
-                       |                      Angustistellæ
-                       |                      +Desmosticha+
-                       |                      +Autechinida+
-                       |                            |
-                       |                            |           Colocrinæ
-                       |                            |               |
-                       |                            | Sphæronitidæ  |
-    Phytastra          |                            |       |       |
-        |              |                            |       |       |
-        |              |                       Eocidaridæ   |       |    Eleutherocrina
-        |              |                            |       |       |           |
-        |              |                            |       |       |           |
-    Ophiastra          |                            |   Agelacrinæ  |           |
-  +Discogastra+        |                            |   +Cystidea+  |           |
-        |              |                            |       |       |           |
-        |              |                            |       |       |           |
-        |              |                        Melonitida  |   Phatnocrinæ     |
-   Brisingastra        |                        Palechinida |   +Brahiata+   Pentremitida
-        |              |                        +Echinida+  |       |        +Blastoidea+
-        |              |                            |       |       |           |
-        |              |                            |       |       |           |
-     Colastra          \----------v-----------------/       \-------v-----------/
-        |                         |                             +Brachiata+
-        |                         |                              Crinoida
-        |                         |                              Crinastra
-        |                         |                                  |
-        \-------------------------v----------------------------------/
-                                  |
-                               Tocastra
-                            +Actinogastra+
-                              +Asterida+
-                                  |
-                             Phracthelminthes
-                                  |
-                               Coelomati
-                                  |
-                                Gastræa
-
-
-Hence the Star-fishes would be compound stocks of worms which, by the
-radial formation of buds, have developed out of true articulated worms,
-or Annelids. This hypothesis is most strongly supported by the
-comparative anatomy, and by the ontogeny of some Star-fishes (Colastra),
-and of segmented worms. The many-jointed Ring-worms (Annelida) in their
-inner structure are closely allied to the individual arms or radii of
-the Star-fishes, that is to the original single worms, which each arm
-represents. Each of the five worms of the Star-fish is a chain composed
-of a great number of equi-formal members, or metamera, lying one behind
-the other, like every segmented Worm, and every Arthropod. As in the
-latter a central nervous cord, the ventral nerve cord runs along the
-central line of the ventral wall of each segment. On each metameron
-there is a pair of non-jointed feet, and besides these, in most cases,
-one or more hard thorns or bristles similar to those of many Ring-worms.
-A detached arm of a Star-fish can lead an independent life, and can
-then, by the radially-directed growth of buds at one end, again become a
-complete star.
-
-The most important proofs, however, of the truth of my hypothesis are
-furnished by the ontogeny or the individual development of the
-Echinoderma. The most remarkable facts of this ontogeny were first
-discovered in the year 1848 by the great zoologist, Johannes Müller of
-Berlin. Some of its most important stages are represented on Plates
-VIII. and IX. (Compare their explanation in the Appendix.) Fig. _A_ on
-Plate IX. shows us a common Sea-star (Uraster), Fig. _B_, a Sea-lily
-(Comatula), Fig. _C_, a Sea-urchin (Echinus), and Fig. _D_, a
-Sea-cucumber (Synapta). In spite of the extraordinary difference of form
-manifested by these four representatives of the different classes of
-Star-fishes, yet the beginning of their development is identical in all
-cases. Out of the egg an animal-form develops which is utterly
-different from the fully developed Star-fish, but very like the ciliated
-larvæ of certain segmented Worms (Star-worms and Ring-worms). This
-peculiar animal-form is generally called the "larva," but more correctly
-the "nurse" of these Star-fish. It is very small and transparent, swims
-about by means of a fringe of cilia, and is always composed of two equal
-symmetrical halves or sides. The fully grown Echinoderm, however--which
-is frequently more than a hundred times larger, and quite opaque--creeps
-at the bottom of the sea, and is always composed of at least five
-co-ordinate pieces, or antimera, in the form of radii. Plate VIII. shows
-the development of the "nurses" of the four Echinoderms represented on
-Plate IX.
-
-The fully developed Echinoderm arises by a very remarkable process of
-budding in the interior of the "nurse," of which it retains little more
-than the stomach. The nurse, erroneously called the "larva," of the
-Echinoderm, must accordingly be regarded as a solitary worm, which by
-internal budding produces a second generation, in the form of a stock of
-star-shaped and connected worms. The whole of this process is a genuine
-alternation of generations, or metagenesis, not a "metamorphosis," as is
-generally though erroneously stated. A similar alternation of
-generations also occurs in many other worms, especially in some star
-worms (Sipunculidæ), and cord worms (Nemertinæ). Now if, bearing in mind
-the fundamental law of biogeny, we refer the ontogeny of Echinoderma to
-their phylogeny, then the whole historical development of the
-Star-fishes suddenly becomes clear and intelligible to us, whereas
-without this hypothesis it remains an insoluble mystery. (Compare Gen.
-Morph. ii. pp. 95-99.)
-
-Besides the reasons mentioned, there are many other facts (principally
-from the comparative anatomy of Echinoderma) which most distinctly prove
-the correctness of my hypothesis. I established this hypothesis in 1866,
-without having any idea that _fossil articulated worms_ still existed,
-apparently answering to the hypothetical primary forms. Such have in the
-mean time, however, really been discovered. In a treatise "On the
-Equivalent of the North American Taconic Schist in Germany,"[3] Geinitz
-and Liebe, in 1867, have described a number of articulated Silurian
-worms, which completely confirm my suppositions. Numbers of these very
-remarkable worms are found in an excellent state of preservation in the
-slates of Würzbach, in the upper districts of Reusz. They are of the
-same structure as the articulated arm of a Star-fish, and evidently
-possessed a hard coat of mail, a much denser, more solid cutaneous
-skeleton than other worms in general. The number of body-segments, or
-metamera, is very considerable, so that the worms, although no more than
-a quarter or half an inch in breadth, attained a length of from two to
-three feet. The excellently preserved impressions, especially those of
-the Phyllodocites thuringiacus and Crossopodia Henrici, are so like the
-arms of many Star-fish (Colastra) that their true blood relationship
-seems very probable. This primæval group of worms, which are most
-probably the ancestors of Star-fish, I call Mailed worms
-(Phracthelminthes, p. 150.)
-
-[Illustration: Pl. viii.
-
-STAR FISHES. FIRST GENERATION. WORM PERSON.]
-
-[Illustration: Pl. ix.
-
-STAR FISHES. SECOND GENERATION. WORM STOCK.]
-
-The three other classes of Echinoderma evidently arose at a later period
-out of the class of Sea-stars which have most faithfully retained the
-original form of the stellate colony of worms. The Sea-lilies, or
-Crinoida, differ least from them, but having given up the free, slow
-motion possessed by other Sea-stars, they have become adherent to rocks,
-etc., and form for themselves a long stalk. Some Encrinites, however
-(for example, the Comatulæ, Fig. _B_, on Plates VIII. and IX.),
-afterwards detach themselves from their stalk. The original worm
-individuals in the Crinoida are indeed no longer preserved in the same
-independent condition as in the case of the common star-fish; but they
-nevertheless always possess articulated arms extending from a common
-central disc. Hence we may unite the Sea-lilies and Sea-stars into a
-main-class, or branch, characterized as possessing articulated arms
-(Colobrachia).
-
-In the other two classes of Echinoderma, the Sea-urchins and
-Sea-cucumbers, the articulated arms are no longer present as independent
-parts, but, by the increased centralization of the stock, have
-completely fused so as to form a common, inflated, central disc, which
-now looks like a simple box or capsule without arms. The original stock
-of five individuals has apparently degenerated to the form-value of a
-simple individual, a single person. Hence we may represent these two
-classes as a branch characterized as being without arms (Lipobrachia),
-equivalent to those which possess articulated arms. The first of these
-two classes, that of Sea-urchins (Echinida) takes its name from the
-numerous and frequently very large thorns which cover the hard shell,
-which is itself artistically built up of calcareous plates. (Fig. _C_,
-Plates VIII. and IX.) The fundamental form of the shell itself is a
-pentagonal pyramid. The Sea-urchins probably developed directly out of
-the group of Sea-stars. The different classes and orders of marine
-lilies and stars which are given in the following table, illustrate the
-laws of progress and differentiation in a striking manner. In each
-succeeding period of the earth's history we see the individual classes
-continually increasing in variety and perfection. (Gen. Morph. ii. Plate
-IV.)
-
-The history of three of these classes of Star-fish is very minutely
-recorded by numerous and excellently preserved fossils, but on the other
-hand, we know almost nothing of the historical development of the fourth
-class, that of the Sea-cucumbers (Holothuriæ). These curious
-sausage-shaped Star-fish manifest externally a deceptive similarity to
-worms. (Fig. _D_, Plates VIII. and IX.) The skeletal structures in their
-skin are very imperfect, and hence no distinct remains of their
-elongated, cylindrical, worm-like body could be preserved in a fossil
-state. However, from the comparative anatomy of the Holothuriæ, we can
-infer that they have arisen, by the softening of the cutaneous skeleton,
-from members of the class of Sea-urchins.
-
-From the Star-fish we turn to the fifth and most highly developed tribe
-of the invertebrate animals, namely, the phylum of Articulata, or those
-with _jointed feet_ (Arthropoda). As has already been remarked, this
-tribe corresponds to Linnæus' class of Insects. It contains four
-classes: (1) the genuine six-legged Insects, or Flies; (2) the
-eight-legged Spiders; (3) the Centipedes, with numerous pairs of legs;
-and (4) the Crabs, or Crustacea, whose legs vary in number. The last
-class breathe water through gills, and may therefore be contrasted as
-the main-class of gill-breathing Arthropoda, or Gilled Insects
-(Carides), with the three first classes. The latter breathe air by means
-of peculiar wind-pipes, or tracheæ, and may therefore appropriately be
-united to form the main-class of the trachea-breathing Arthropoda, or
-Tracheate Insects (Tracheata).
-
-In all animals with articulated feet, as the name indicates, the legs
-are distinctly articulated, and by this, as well as by the strong
-differentiation of the separate parts of the body, or metamera, they are
-sharply distinguished from Ringed worms, with which Bär and Cuvier
-classed them. They are, however, in every respect so like the Ringed
-worms that they can scarcely be considered altogether distinct from
-them. They, like the Ringed worms, possess a very characteristic form of
-the central nervous system, the so-called ventral marrow, which
-commences in a gullet-ring encircling the mouth. From other facts also,
-it is evident that the Arthropoda developed at a late period out of
-articulated worms. Probably either the Wheel Animalcules or the Ringed
-worms are their nearest blood relations in the Worm tribe. (Gen. Morph.
-ii. Plate V. pp. 85-102.)
-
-Now, although the derivation of the Arthropoda from ringed Worms may be
-considered as certain, still it cannot with equal assurance be
-maintained that the whole tribe of the former has arisen out of one
-branch of the latter. For several reasons seem to support the
-supposition that the Gilled Arthropods have developed out of a branch of
-articulated worms, different from that which gave rise to the Tracheate
-Arthropods. But on the whole it remains more probable that both
-main-classes have arisen out of one and the same group of Worms. In this
-case the Tracheate Insects--Spiders, Flies, and Centipedes--must have
-branched off at a later period from the gill-breathing Insects, or
-Crustacea.
-
-The pedigree of the Arthropoda can on the whole be clearly made out from
-the palæontology, comparative anatomy, and ontogeny of its four
-classes, although here, as everywhere else, many details remain very
-obscure. Not until the history of the individual development of all the
-different groups has become more accurately known than it is at present,
-can this obscurity be removed. The history of the class of Gilled
-Insects, or Crabs (Carides), is at present that best known to us; they
-are also called encrusted animals (Crustacea), on account of the hard
-crust or covering of their body. The ontogeny of these animals is
-extremely interesting and, like that of Vertebrate animals, distinctly
-reveals the essential outlines of the history of their tribe, that is,
-their phylogeny. Fritz Müller, in his work, "Für Darwin,"(16) which has
-already been referred to, has explained this remarkable series of facts
-in a very able manner.
-
-[Illustration: _Nauplius. Youth-form of six Crab-fish._ _Pl. X._
-
-  A. Limnetis.
-  B. Cyclops.
-  C. Lernacocera.
-  D. Lepas.
-  E. Sacculina.
-  F. Peneus.]
-
-[Illustration: _Adult form of the same six Crab-fish._ _Pl. XI._
-
-  A. Limnetis.
-  B. Cyclops.
-  C. Lernacocera.
-  D. Lepas.
-  E. Sacculina.
-  F. Peneus.]
-
-The common primary form of all Crabs, which in most cases is even now
-the first to develop out of the egg, is originally one and the same, the
-so-called _Nauplius_. This remarkable primæval crab represents a very
-simple form of articulated animal, the body of which in general has the
-form of a roundish, oval, or pear-shaped disc, and has on its ventral
-side only three pairs of legs. The first of these is uncloven, the two
-subsequent pairs are forked. In front, above the mouth, lies a simple,
-single eye. Although the different orders of the Crustacean class differ
-very widely from one another in the structure of their body and its
-appendages, yet the early Nauplius form always remains essentially the
-same. In order to be convinced of this, let the reader look attentively
-at Plates X. and XI., a more detailed explanation of which is given in
-the Appendix. On Plate XI. we see the fully developed representatives of
-six different orders of Crabs, a Leaf-footed Crab (Limnetis, Fig. _A
-c_); a Stalked Crab (Lepas, Fig. _D c_); a Root Crab (Sacculina, Fig.
-_E c_); a Boatman Crab (Cyclops, Fig. _B c_); a Fish Louse (Lernæocera,
-Fig. _C c_); and, lastly, a highly developed Shrimp (Peneus, Fig. _F
-c_). These six crabs vary very much, as we see, in the entire form of
-body, in the number and formation of the legs, etc. When, however, we
-look at the earliest stages, or "nauplius," of these six different
-classes, after they have crept out of the egg--those marked with
-corresponding letters on Plate X. (Fig. _A n-F n_)--we shall be
-surprised to find how much they agree. The different forms of Nauplius
-of these six orders differ no more from one another than would six
-different "good species" of one genus. Consequently, we may with
-assurance infer a common derivation of all those orders from a common
-Primæval Crab, which was essentially like the Nauplius of the present
-day.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 7 Legions and 20 Orders of Crabs, or Crustacea._
-
-
-  -------------------------+--------------------------+----------------------+--------------
-     _Legions of the_      |     _Orders of the_      |    _Systema  Name_   |  _Name of a_
-      _Crustaceæ._         |      _Crustaceæ._        |    _of the Orders._  | _Genus as an_
-                           |                          |                      |  _example._
-  -------------------------+--------------------------+----------------------+--------------
-  I. ENTOMOSTRACA, _Lower Crustacea_, or Segmented Crabs (not passing through the
-                             actual Zoëa form in youth).
-  ------------------------------------------------------------------------------------------
-
-  +I. Branchiopoda+         { 1. Primæval Crabs         1. Archicarida         Nauplius
-  Gill-footed Crabs         { 2. Leaf-foot Crabs        2. Phyllopoda          Limnetis
-                            { 3. Trilobites             3. Trilobita           Paradoxides
-                            { 4. Water Fleas            4. Cladocera           Daphnia
-                            { 5. Bivalve Crabs          5. Ostracoda           Cypris
-
-
-  +II. Pectostraca+         { 6. Barnacle Crabs         6. Cirripedia          Lepas
-    Fixed Crabs             { 7. Root Crabs             7. Rhizocephala        Sacculina
-
-  +III. Copepoda+           { 8. Boatmen Crabs          8. Eucopepoda          Cyclops
-  Oar-footed Crabs          { 9. Fish Lice              9. Siphonostoma        Lernæocera
-
-  +IV. Pantopoda+           {10. No-body Crabs         10. Pycnogonida         Nymphon
-   No-body Crabs            {
-
-  +V. Poecilopoda+          {11. Spear-tails           11.  Xiphosura          Limulus
-   Shield Crabs             {12. Giant Crabs           12.  Gigantostraca      Eurypterus
-
-  ------------------------------------------------------------------------------------------
-  II. MALACOSTRACA, _Higher Crustacea_, or Mailed Crabs (passing through the Zoëa form
-                                     in youth).
-  ------------------------------------------------------------------------------------------
-
-  +VI. Podophthalma+        {13. Zoëa Crabs            13. Zoëpoda            Zoëa
-  Stalk-eyed Mailed         {14. Split-legged Crabs    14. Schizopoda         Mysis
-  Crabs                     {15. Mouth-footed Crabs    15. Stomatopoda        Squilla
-                            {16. Ten-footed Crabs      16. Decapoda           Peneus
-
-  +VII. Edriophthalma+      {17. Cuma Crabs            17. Cumacea            Cuma
-   Mailed Crabs with        {18. Flea Crabs            18. Amphipoda          Gammarus
-    sessile eyes            {19. Wizard Crabs          19. Læmodipoda         Caprella
-                            {20. Louse Crabs           20. Isopoda            Oniscus
-
-        ----------------------------------------------------------------
-
-
-  Brachyura                                            Isopoda
-      |                                                   |
-      |                                    Læmodipoda     |
-      |                                        |          |
-  Anomura                                      |          |
-      |                                        |          |
-      |                                     Amphipoda     |
-      |                                        |          |
-      |                                        \-----v----/
-  Macrura                                           |
-  Decapoda  Stomatopoda                          Cumacea
-      |         |                            +Edriophthalma+
-      |         |                                   |
-      \----v----/                                   |
-           |                                        |
-           |                                        |
-           \---------------------------v------------/
-                                       |
-                                    Schizopoda
-                                  +Podophthalma+
-                                       |
-                                    Zoëpoda
-                                +Malacostraca+
-  Gigantostraca                        |                 Rhizocephala
-         |                             |  Siphonostoma        |
-         |         Xiphosuræ         Zoëa      |          Cirripediæ
-         |             |               |       |         +Pectostraca+
-         |             |               |       |              |
-         \------v------/               |       |              |
-                |                      |       |              |
-        +Poecilopoda+                  |       |              |
-                |            Nebaliæ   |       |              |
-                |               |      |  Eucopepoda          |
-            Belinuroe           |      |  +Copepoda+          |     Pycnogonida
-                |               |      |       |              |     +Pantopoda+
-            Trilobita           |      |       |              |          |
-                |           Phyllopoda |       |  Ostracoda   |          |
-  Cladoceræ     |               |      |       |      |       |          |
-      |         |               |      |       |      |       |          |
-      \-----------------v-------/      |       |      \---v---/          |
-                        |              |       |          |              |
-                 +Branchiopoda+        |       |          |              |
-                        |              |       |          |              |
-                        |              |       |          |              |
-                        \----------------------v-------------------------/
-                                               |
-                                            Nauplius
-                                               |
-                                          +Archicaridæ+
-
-                                        (Articulated Worms)
-
-
-The pedigree on p. 177 will show how we may at present approximately
-conceive the derivation of the twenty orders of Crustacea enumerated on
-p. 176, from the common primary form of the Nauplius. Out of the
-Nauplius form--which originally existed as an independent genus--the
-five legions of lower Crabs developed as diverging branches in different
-directions, which in the systematic survey of the class are united as
-Segmented Crabs (Entomostraca). The higher division of Mailed Crabs
-(Malacostraca) have likewise originated out of the common Nauplius form.
-The Nebalia is still a direct form of transition from the Phyllopods to
-the Schizopods, that is, to the primary form of the stalk-eyed and
-sessile-eyed Mailed Crabs. The Nauplius at this stage gives rise to
-another larva form, the so-called Zoëa, which is of great importance.
-The order of Schizopoda, those with cloven feet (Mysis, etc.), probably
-originated from this curious Zoëa; they are at present still directly
-allied, through the Nebalia to the Phyllopoda, those with foliaceous
-feet. But of all living crabs the Phyllopods are the most closely allied
-to the original primary form of the Nauplius. Out of the Schizopoda the
-stalk-eyed and sessile-eyed Mailed Crabs, or Malacostraca, developed as
-two diverging branches in different directions: the former through
-shrimps (Peneus, etc.), the latter through the Cumacea (Cuma, etc.),
-which are still living and closely allied to the Schizopoda. Among those
-with stalked eyes is the river crab (cray-fish), the lobster, and the
-others with long tails, or the Macrura, out of which, in the chalk
-period, the short-tailed crabs, or Brachyura, developed by the
-degeneration of the tail. Those with sessile eyes divide into the two
-branches of Flea-crabs (Amphipoda) and Louse-crabs (Isopoda); among the
-latter are our common Rock-slaters and Wood-lice.
-
-The second main-class of Articulated animals, that of the Tracheata, or
-air-breathing Tracheate Insects[4] (Spiders, Centipedes, and Flies) did
-not develop until the beginning of the palæolithic era, after the close
-of the archilithic period, because all these animals (in contrast with
-the aquatic crabs) are originally inhabitants of land. It is evident
-that the Tracheata can have developed only after the lapse of the
-Silurian period when terrestrial life first began. But as fossil remains
-of spiders and insects have been found, even in the carboniferous beds,
-we can pretty accurately determine the time of their origin. The
-development of the first Tracheate Insects out of gill-bearing
-Zoëa-crabs, must have taken place between the end of the Silurian and
-the beginning of the coal period, that is, in the Devonian period.
-
-Gegenbaur, in his excellent "Outlines of Comparative Anatomy,"(21) has
-lately endeavoured to explain the origin of the Tracheata by an
-ingenious hypothesis. The system of tracheæ, or air pipes, and the
-modifications of organization dependent upon it, distinguish Flies,
-Centipedes, and Spiders so much from other animals, that the conception
-of its first origin presents no inconsiderable difficulties to
-phylogeny. According to Gegenbaur, of all living Tracheate Insects, the
-Primæval Flies, or Archiptera, are most closely allied to the common
-primary form of the Tracheata. These insects--among which we may
-especially mention the delicate Day flies (Ephemera), and the agile
-dragon-flies (Libellula)--in their earliest youth, as larvæ, frequently
-possess _external tracheate gills_ which lie in two rows on the back of
-the body, and are shaped like a leaf or paint-brush. Similar leaf or
-paint-brush shaped organs are met with as real water-breathing organs or
-gills, in many crabs and ringed worms, and, moreover, in the latter as
-real dorsal appendages or limbs. The "tracheate gills," found in the
-larvæ of many primæval winged insects, must in all probability be
-explained as "_dorsal limbs_," and as having developed out of the
-corresponding appendages of the Annelida, or possibly as having really
-arisen out of similar parts in Crustacea long since extinct. The present
-tracheal respiration of the Tracheata developed at a later period out of
-respiration through the "tracheate gills." The tracheate gills
-themselves, however, have in some cases disappeared, and in others
-become transformed into the _wings_ of the Flies. They have disappeared
-entirely in the classes of Spiders and Centipedes, and these groups must
-accordingly be conceived of as degenerated or peculiarly developed
-lateral branches of the Fly class, which at an early period branched off
-from the common primary form of Flies; Spiders probably did so at an
-earlier period than Centipedes. Whether that common primary form of all
-Tracheata, which in my General Morphology I have named Protracheata, did
-develop directly out of genuine Ringed worms, or at first out of
-Crustacea of the Zoëa form (Zoëpoda, p. 177) will probably be settled at
-some future time by a more accurate knowledge and comparison of the
-ontogeny of the Tracheata, Crustacea, and Annelida. However, the root of
-the Tracheata, as well as that of the Crustacea, must in any case be
-looked for in the group of Ringed worms.
-
-The genuine Spiders (Arachnida) are distinguished from Flies by the
-absence of wings, and by four pairs of legs; but, as is distinctly seen
-in the Scorpion-spiders and Tarantulæ, they, like Flies, possess in
-reality only three pairs of genuine legs. The apparent "fourth pair of
-legs" in spiders (the foremost) are in reality a pair of feelers. Among
-the still existing Spiders, there is a small group which is probably
-very closely allied to the common primary form of the whole class; this
-is the order of Scorpion-spiders, or Solifugæ, (Solpuga, Galeodes), of
-which several large species live in Africa and Asia, and are dreaded on
-account of their poisonous bite. Their body consists--as we suppose to
-have been the case in the common ancestor of the Tracheata--of a head
-possessing several pairs of feelers like legs, of a thorax, to the three
-rings of which are attached three pairs of legs, and of a hinder body,
-or abdomen, consisting of many distinct rings. In the articulation of
-their body, the Solifugæ are therefore in reality more closely related
-to flies than to other spiders. Out of the Devonian Primæval Spiders,
-which were nearly related to the Solifugæ of the present day, the Long
-Spiders, the Tailor Spiders, and the Round Spiders probably developed as
-three diverging branches.
-
-The _Long Spiders_ (Arthrogastres), in which the earlier articulation of
-body has been better preserved than in Round Spiders, appear to be the
-older and more original forms. The most important members of this
-sub-class are the scorpions, which are connected with the Solifugæ
-through the Tarantella (or Phrynidæ). The small book scorpions, which
-inhabit our libraries and herbariums, appear as a degenerate lateral
-branch from the true scorpions. Midway between the Scorpions and Round
-Spiders are the long-legged Tailor-spiders (Opiliones) which have
-possibly arisen out of a special branch of the Solifugæ. The
-Pycnogonida, or No-body Crabs, and the Arctisca, or Bear Worms--still
-generally included among Long Spiders--must be completely excluded from
-the class of Spiders; the former belong to the Crustacea, the latter to
-Ringed worms.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 3 Classes and 17 Orders of the Tracheata._
-
-
-  ------------------+---------------------+----------------------+----------------------
-  _Classes of the_  | _Sub-Classes of the_|   _Order of the_     |   _Two Names of_
-    _Tracheata._    |     _Tracheata._    |     _Tracheata._     |_Genera as examples._
-  ------------------+---------------------+----------------------+----------------------
-                    {                     {  1. Scorpion spiders  { Solpuga
-                    {                     {    _Solifugæ_         { Galeodes
-                    {                     {
-                    {                     {  2. Tarantella        { Phrynus
-                    {                     {    _Phrynida_         { Thelyphonus
-                    {         I.          {
-           I.       {     Long spiders    {  3. Scorpions         { Scorpio
-        =Spiders=   {    _Arthrogastres_  {    _Scorpioda_        { Buthus
-                    {                     {
-       +Arachnida+  {                     {  4. Book scorpions    { Obisium
-                    {                     {    _Pseudoscorpioda_  { Chelifer
-                    {                     {
-                    {                     {  5. Tailor spiders    { Phalangium
-                    {                     {    _Opilionida_       { Opilio
-                    {
-                    {
-                    {         II.         {  6. Spinning spiders  { Epeira
-                    {     Round spiders   {    _Araneæ_           { Mygale
-                    {                     {                       {
-                    {    _Sphærogastres_  {  7. Mites             { Sarcoptes
-                    {                     {    _Acarida_          { Demodex
-
-
-          II.       {          III.
-      =Centipedes=  {      Simple-footed  {  8. Simple-footed     { Scolopendra
-                    {       _Chilopoda_   {    _Chilopoda_        { Geophilus
-                    {                     {
-     +Scolopendria+ {          IV.        {  9. Double-footed     { Julus
-           or       {      Double-footed  {    _Diplopoda_        { Polydesmus
-       +Myriapoda+  {       _Diplopoda_   {
-
-
-                    {                     { 10. Primitive flies   { Ephemera
-                    {                     {    _Archiptera_       { Libellula
-                    {                     {
-                    {                     { 11. Gauze-wings       { Hemerobius
-                    {                     {    _Neuroptera_       { Phryganea
-                    {           V.        {
-                    {        Chewing      { 12. Straight-wings    { Locusta
-                    {     _Masticantia_   {    _Orthoptera_       { Forficula
-                    {                     {
-          III.      {                     { 13. Beetles           { Cicindela
-         =Flies=    {                     {    _Coleoptera_       { Melolontha
-                    {                     {
-       +Hexapoda+   {                     { 14. Bee-wings         { Apis
-                    {                     {    _Hymenoptera_      { Formica
-                    {
-                    {
-                    {                     { 15. Bugs              { Aphis
-                    {          VI.        {    _Hemiptera_        { Cimex
-                    {        Sucking      {
-                    {      _Sugentia_     { 16. Two-wings         { Culex
-                    {                     {    _Diptera_          { Musca
-                    {                     {
-                    {                     { 17. Butterflies       { Bombyx
-
-        ----------------------------------------------------------------
-
-                                Butterflies
-                               _Lepidoptera_
-                                     |
-                     Bees            |           Two-wings
-                 _Hymenoptera_       |           _Diptera_
-                       |             |               |
-                       |             |               |
-      Beetles          |             |               |             Bugs
-  _Coleoptera_         \-------v-----/               |          _Hemiptera_
-        |                      |                     |              |
-        |                 Gauze wings                |              |
-  Straight-wings          _Neuroptera_               \-------v------/
-  _Orthoptera_                 |                             |
-        |                      |                             |
-        |                      |                             |
-        \----------------------v-----------------------------/
-
-                                         Primæval Flies
-                                          _Archiptera_
-                                               |
-                                  Scorpions    |             Double-footed
-                                 _Scorpioda_   |              _Diplopoda_
-             Tailor Spiders            |       |                   |
-              _Opiliones_              |       |                   |
-                   |  Book Scorpions   |       |                   |
-       Mites       | _Pseudoscorpioda_ |       |                   |
-      _Acarida_    |       |           |       |                   |
-          |        |       \-----v-----/       |                   |
-          |        |             |             |                   |
-          |        |         Tarantella        |                   |
-   Weaving Spiders |         _Phrynida_        |              Simple-footed
-      _Araneæ_     |             |             |               _Chilopoda_
-          |        |             |             |               =Centipedes=
-          |        |             |             |               +Myriapoda+
-          \-------------v--------/             |                   |
-                        |                      |                   |
-                 Scorpion Spiders              |                   |
-                   _Solifugæ_                  |                   |
-                    =Spiders.=                 |                   |
-                   +Arachnida+                 |                   |
-                        |                      |                   |
-                        |                    =Flies=               |
-                        |               +Insecta Hexapoda+         |
-                        |                      |                   |
-                        |                      |                   |
-                        \--------------------v---------------------/
-                                             |
-                               Primary Air-breathing Arthropods
-                                        _Protracheata_
-                                             |
-                                             |
-                                      Articulated Worms
-                                        _Coelminthes_
-
-Fossil remains of Long Spiders are found in the Coal. The second
-sub-class of the Arachnida, the _Round Spiders_ (Sphærogastres), first
-appear in the fossil state in the Jura, that is, at a very much later
-period. They have developed out of a branch of the Solifuga, by the
-rings of the body becoming more and more united with one another. In the
-true _Spinning Spiders_ (Araneæ), which we admire on account of their
-delicate skill in weaving, the union of the joints of the trunk, or
-metamera, goes so far, that the trunk now consists of only two pieces,
-of a head-breast (cephalo-thorax) with jaws, feelers, and four pairs of
-legs, and of a hinder body without appendages, where the spinning warts
-are placed. In _Mites_ (Acarida), which have probably arisen by
-degeneration (especially by parasitism) out of a lateral branch of
-Spinning Spiders, even these two trunk pieces have become united and now
-form an unsegmented mass.
-
-The class of _Scolopendria_, _Myriapoda_, or Centipedes, the smallest
-and poorest in forms of the four classes of Arthropoda, is characterized
-by a very elongated body, like that of a segmented Ringed worm, and
-often possesses more than a hundred pairs of legs. But these animals
-also originally developed out of a six-legged form of Tracheata, as is
-distinctly proved by the individual development of the millipede in the
-egg. Their embryos have at first only three pairs of legs, like genuine
-insects, and only at a later period do the posterior pairs of legs bud,
-one by one, from the growing rings of the hinder body. Of the two orders
-of Centipedes (which in our country live under barks of trees, in moss,
-etc.) the round, _double-footed_ ones (Diplopoda) probably did not
-develop until a later period out of the older flat, _single-footed_ ones
-(Chilopoda), by successive pairs of rings of the body uniting together.
-Fossil remains of the Chilopoda are first met with in the Jura period.
-
-The third and last class of the Arthropoda breathing through tracheæ, is
-that of the _Flies_, or _Insects_, in the narrow sense of the word
-(Insecta, or Hexapoda), the largest of all classes of animals, and next
-to that of Mammalia, also the most important. Although Flies develop a
-greater variety of genera and species than all other animals taken
-together, yet these are all in reality only superficial variations of a
-single type, which is entirely and constantly preserved in its essential
-characteristics. In all Flies the three divisions of the trunk--head,
-breast (thorax), and hinder body are quite distinct. The _hinder body_,
-or _abdomen_, as in the case of spiders, has no articulated appendages.
-The central division, the _breast_ or _thorax_, has on its ventral side
-three pairs of legs, on its back _two pairs of wings_. It is true that,
-in very many Flies, one or both pairs of wings have become reduced in
-size or have even entirely disappeared; but the comparative anatomy of
-Flies distinctly shows that this deficiency has arisen only gradually by
-the degeneration of the wings, and that all the Flies existing at
-present are derived from a common, primary Fly, which possessed three
-pairs of legs and two pairs of wings. (Compare p. 256.) These wings,
-which so strikingly distinguish Flies from all other Arthropoda,
-probably arose, as has been already shown, out of the tracheate gills
-which may still be observed in the larvæ of the ephemeral flies
-(Ephemera) which live in water.
-
-The head of Flies universally possesses, besides the eyes, a pair of
-articulated feelers, or antennæ, and also three jaws upon each side of
-the mouth. These _three pairs of jaws_, although they have arisen in all
-Flies from the same original basis, by different kinds of adaptation,
-have become changed to very varied and remarkable forms in the various
-orders, and are therefore employed for distinguishing and characterizing
-the main divisions of the class. In the first place, we may distinguish
-two main divisions, namely, Flies with _chewing_ mandibles (Masticantia)
-and Flies with _sucking_ mouths (Sugentia). On a closer examination each
-of these two divisions may again be divided into two sub-groups. Among
-chewing Flies, or Masticantia, we may distinguish the biting and the
-licking ones. _Biting flies_ (Mordentia) comprise the most ancient and
-primæval winged Flies, the gauzy-winged (Neuroptera), straight-winged
-(Orthoptera), and beetles (Coleoptera). _Licking flies_ (Lambentia) are
-represented by the one order of skin-winged (Hymenoptera) Flies. We
-distinguish two groups of _Sucking Flies_, or Sugentia, namely, those
-which prick and those which sip. There are two orders of pricking Flies
-(Pungentia), those with half wings (Hemiptera) and gnats and blow-flies
-(Diptera); butterflies are the only _sipping_ Flies (Sorbentia),
-Lepidoptera.
-
-Biting Flies, and indeed the order of _Primæval Flies_ (Archiptera, or
-Pseudoneuroptera) are nearest akin to the still living Flies, and
-include the most ancient of all Flies, the primary forms of the whole
-class (hence also those of all Tracheata). Among them are, first of all,
-the Ephemeral Flies (Ephemera) whose larvæ which live in water, in all
-probability still show us in their tracheæ-gills the organs out of which
-the wings of Flies were originally developed. This order further
-contains the well known dragon-flies, or Libellula, the wine-glass sugar
-mites (Lepisma), the hopping Flies with bladder-like feet (Physopoda),
-and the dreaded Termites, fossil remains of which are found even in
-coal. The order of Gauze-winged Flies (Neuroptera), probably developed
-directly out of the primæval Flies, which differ from them only by their
-perfect series of transformations. Among them are the gauze-flies
-(Planipennia), caddis-flies (Phryganida), and fan-flies (Strepsiptera).
-Fossil Flies, which form the transition from the primæval Flies
-(Libellula) to the gauze-winged (Sialidæ), are found even in coal
-(Dictyophylebia).
-
-The order of _Straight-winged Flies_ (Orthoptera) developed at an early
-period out of another branch of the primæval Flies by differentiation of
-the two pairs of wings. This division is composed of one group with a
-great variety of forms--cockroaches, grasshoppers, crickets, etc.
-(Ulonata)--and of a smaller group consisting only of the well-known
-earwigs (Labidura), which are characterised by nippers at the hinder end
-of their bodies. Fossil remains of cockroaches, as well as of crickets
-and grasshoppers, have been found in coal.
-
-Fossil remains of the fourth order of Biting Flies, _beetles_
-(Coleoptera) likewise occur in coal. This extremely comprehensive
-order--the favourite one of amateurs and collectors--shows more clearly
-than any other what infinite variety of forms can be developed
-externally by adaptation to different conditions of life, without the
-internal structure and the original form of the body being in any way
-essentially changed. Beetles have probably developed out of a branch of
-the straight-winged Flies, from which they differ only in their
-transformations (larva, pupa, etc.).
-
-The one order of _Licking Flies_, namely, the interesting group of the
-_Bees_, or _Skin-winged Flies_ (Hymenoptera), is closely allied to the
-four orders of biting Flies. Among them are those Flies which have risen
-to such an astonishing degree of mental development, of intellectual
-perfection, and strength of character, by their extensive division of
-labour, formation of communities and states, and surpass in this not
-merely most invertebrate animals, but even most animals in general. This
-may be said especially of all ants and bees, also of wasps, leaf-wasps,
-wood-wasps, gall-wasps, etc. They are first met with in a fossil state
-in the oolites, but they do not appear in greater numbers until the
-tertiary period. Probably these insects developed either out of a branch
-of the primæval Flies or the gauze-winged Flies.
-
-Of the two orders of _Pricking Flies_ (Hemiptera and Diptera), that
-containing the _Half-winged Flies_ (Hemiptera), also called Beaked Flies
-(Rhynchota), is the older of the two. It includes three sub-orders,
-viz., the leaf-lice (Homoptera), the bugs (Heteroptera), and lice
-(Pediculina). Fossil remains of the first two classes are found in the
-oolites; but an ancient Fly (Eugereon) is found in the Permian system,
-and seems to indicate the derivation of the Hemiptera from the
-Neuroptera. Probably the most ancient of the three sub-orders of the
-Hemiptera are the Homoptera, among which, besides the actual leaf-lice,
-are the shield-lice, leaf-fleas, and leaf-crickets, or Cicadæ. Lice have
-probably developed out of two different branches of Homoptera, by
-continued degeneration (especially by the loss of wings); bugs, on the
-other hand, by the perfecting and differentiation of the two pairs of
-wings.
-
-The second order of _pricking flies_, namely, the _Two-winged Flies_
-(Diptera), are also found in a fossil state in the oolites, together
-with Half-winged Flies; but they probably developed out of the Hemiptera
-by the degeneration of the hind wings. In Diptera the fore wings alone
-have remained perfect. The principal portion of this order consists of
-the elongated gnats (Nemocera) and of the compact blow-flies and
-house-flies (Brachycera), the former of which are probably the older of
-the two. However, remains of both are found in the oolitic period. The
-two small groups of lice-flies (Pupipara) forming chrysales, and the
-hopping-fleas (Aphaniptera), probably developed out of the Diptera by
-degeneration resulting from parasitism.
-
-The eighth and last order of Flies, and at the same time the only one
-with mouth-parts adapted to sipping liquids, consists of _moths_ and
-_butterflies_ (Lepidoptera). This order appears, in several
-morphological respects, to be the most perfect class of Flies, and
-accordingly was the last to develop. For we only know of fossil remains
-of this order from the tertiary period, whereas the three preceding
-orders extend back to the oolites, and the four biting orders even to
-the coal period. The close relationship between some moths (Tineæ) and
-(Noctuæ), and some caddis-flies (Phryganida) renders it probable that
-butterflies have developed from this group, that is, out of the order of
-Gauze-winged Flies, or Neuroptera.
-
-The whole history of Flies, and, moreover, the history of the whole
-tribe of Arthropoda, essentially confirms the great laws of
-differentiation and perfecting which, according to Darwin's theory of
-selection, must be considered as the necessary results of Natural
-Selection. The whole tribe, so rich in forms, begins in the Archilithic
-period with the class of _Crabs_ breathing by gills, and with the lowest
-_Primæval Crabs_, or Archicaridæ. The form of these Primæval Crabs,
-which were developed out of segmented worms, is still approximately
-preserved by the remarkable _Nauplius_, in the common larval stage of so
-many Crabs. Out of the Nauplius, at a later period, the curious Zoëa was
-developed, which is the common larval form of all the higher or mailed
-crabs (Malacostraca), and, at the same time, possibly of that Arthopod
-which at first breathed through tracheæ, and became the common ancestor
-of all _Tracheata_. This Devonian ancestor, which must have originated
-between the end of the Silurian and the beginning of the Coal period,
-was probably most closely related to the still living Primæval Flies, or
-_Archiptera_. Out of these there developed, as the main tribe of the
-Tracheata, the class of Flies, from the lowest stage of which the
-_spiders_ and _centipedes_ separated as two diverging branches.
-Throughout a long period there existed only the four biting orders of
-Flies--the Primæval flies, Gauze-wings, Straight-wings, and the Beetles,
-the first of which is probably the common primary form of the three
-others. It was only at a much later period that the Licking, Pricking,
-and Sipping flies developed out of the Biting ones, which retained the
-original form of the three pairs of jaws most distinctly. The following
-table will show once more how these orders succeeded one another in the
-history of the earth.
-
-
-CLASSIFICATION OF FLIES.
-
-                    {                 { 1. Primæval winged   { M.I.  }
-                    {                 {    _Archiptera_      { A.A.  }
-                    {                 {                              }
-                    {      I.         { 2. Gauze-winged      { M.C.  }
-        A.          {  Biting Flies   {    _Neuroptera_      { A.A.  }
-                    {                 {                              }
-      =Flies=       {  _Mordentia_    { 3. Straight-winged   { M.I.  }
-  =with Chewing=    {                 {    _Orthoptera_      { A.D.  }
-     =Mouths=       {                 {                              }
-                    {                 { 4. Beetles           { M.C.  }
-  +Masticantia+     {                 {    _Coleoptera_      { A.D.  }
-                    {
-                    {
-                    {      II.        { 5. Skin-winged       { M.C.  }
-                    {  Licking Flies  {    _Hymenoptera_     { A.A.  }
-                    {   _Lambentia_   {                              }
-                                                                     }
-                                                                     }
-                    {                 { 6. Half-winged       { M.I.  }
-                    {      III.       {    _Hemiptera_       { A.A.  }
-        B.          {  Stinging Flies {                              }
-      =Flies=       {                 { 7. Tway-flies        { M.C.  }
-  =with Sucking=    {   _Pungentia_   {    _Diptera_         { A.D.  }
-     =Mouths=       {
-                    {
-   +Sugentia+       {      IV.        { 8. Butterflies       { M.C.  }
-                    {  Sipping Flies  {    _Lepidoptera_     { A.A.  }
-                    {                 {                      {       }
-                    {   _Sorbentia_   {                      {       }
-
-
-   _Note._--The difference in the metamorphosis or transformation and in
-   the development of the wings of the eight individual orders of Flies
-   is also specified by the following letters: M.I. = Imperfect
-   Metamorphosis. M.C. = Perfect Metamorphosis. (Compare Gen. Morph. ii.
-   p. 99.) A.A. = Equal wings (fore and hinder wings are the same, or
-   differ but little). A.D. = Unequal wings (fore and hinder wings very
-   different in structure and texture, occasioned by strong
-   differentiation).
-
-
-
-
-CHAPTER XX.
-
-PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-III. VERTEBRATE ANIMALS.
-
-
-  The Records of the Creation of Vertebrate Animals (Comparative
-  Anatomy, Embryology, and Palæontology).--The Natural System of
-  Vertebrate Animals.--The Four Classes of Vertebrate Animals,
-  according to Linnæus and Lamarck.--Their increase to Nine
-  Classes.--Main Class of the Tube-hearted, or Skull-less Animals
-  (the Lancelet).--Blood Relationship between the Skull-less Fish
-  and the Tunicates.--Agreement in the Embryological Development
-  of Amphioxus and Ascidiæ.--Origin of the Vertebrate Tribe out of
-  the Worm Tribe.--Main Class of Single-nostriled, or
-  Round-mouthed Animals (Hag and Lampreys).--Main Class of
-  Anamnionate Animals, devoid of Amnion.--Fishes (Primæval Fish,
-  Cartilaginous Fish, Osseous Fish).--Mud-fish, or Dipneusta.--Sea
-  Dragons, or Halisauria.--Frogs and Salamanders, or Amphibia
-  (Mailed Amphibia, Naked Amphibia).--Main Class of Amnionate
-  Animals, or Amniota.--Reptiles (Primary Reptiles, Lizards,
-  Serpents, Crocodiles, Tortoises, Flying-Reptiles, Dragons,
-  Beaked Reptiles).--Birds (Feather-tailed, Fan-tailed,
-  Bush-tailed).
-
-
-Not one of the natural groups of organisms--which, we have designated as
-tribes, or phyla, on account of the blood-relationship of all the
-species included in them--is of such great and exceeding importance as
-the tribe of Vertebrate Animals. For, according to the unanimous opinion
-of all zoologists, man also is a member of the tribe; and his whole
-organization and development cannot possibly be distinguished from that
-of other Vertebrate animals. But as from the individual history of
-human development, we have already recognized the undeniable fact that,
-in developing out of the egg, man at first does not differ from other
-Vertebrate animals, and especially from Mammals, we must necessarily
-come to the conclusion, in regard to the palæontological history of his
-development, that man has, historically, actually developed out of the
-lower Vertebrata, and that he is directly derived from lower mammals.
-This circumstance, together with the many high interests which, in other
-respects, entitle the Vertebrata to more consideration than other
-organisms, justifies us in examining the pedigree of the Vertebrata and
-its expression in the natural system, with special care.
-
-Fortunately, the records of creation, which must in all cases be our
-guide in establishing pedigrees, are especially complete in this
-important animal tribe, from which our own race has arisen. Even at the
-beginning of our century Cuvier's comparative anatomy and palæontology,
-and Bär's ontogeny of the Vertebrate animals, had brought us to a high
-level of accurate knowledge on this matter. Since then it is especially
-due to Johannes Müller's and Rathke's investigations in comparative
-anatomy, and most recently to those of Gegenbaur and Huxley, that our
-knowledge of the natural relationships among the different groups of
-Vertebrata has become enlarged. It is especially Gegenbaur's classical
-works, penetrated as they are throughout with the fundamental principles
-of the Theory of Descent, which have demonstrated that the material of
-comparative anatomy receives its true importance and value only by the
-application of the Theory of Descent, and this in the case of all
-animals, but especially in that in the Vertebrate tribe. Here, as
-everywhere else, analogies must be traced to Adaptation, homologies to
-Transmission by Inheritance. When we see that the limbs of the most
-different Vertebrata, in spite of their exceedingly different external
-forms, nevertheless possess essentially the same internal structure;
-when we see that in the arm of a man and ape, in the wing of a man or a
-bird, in the breast fins of whales and sea-dragons, in the fore-legs of
-hoofed animals and frogs, the same bones always lie in the same
-characteristic position, articulation and connection--we can only
-explain this wonderful agreement and homology by the supposition of a
-common transmission by inheritance from a single primary form. On the
-other hand, the striking differences of these homologous bodily parts
-proceed from adaptation to different conditions of existence. (Compare
-Plate IV.)
-
-Ontogeny, or the individual history of development, like comparative
-anatomy, is of especial importance to the pedigree of the Vertebrata.
-The first stages of development arising out of the egg are essentially
-identical in all Vertebrate animals, and retain their agreement the
-longer, the nearer the respective Vertebrate animal forms, when fully
-developed, stand to one another in the natural system, that is, in the
-pedigree. How far this agreement of germ forms, or embryos, extends,
-even in the most highly developed Vertebrate animals, I have already had
-occasion to explain (vol i. pp. 306-309). The complete agreement in form
-and structure, for example, in the embryos of a man and a dog, of a bird
-and a tortoise, existing in the stages of development represented on
-Plates II. and III., is a fact of incalculable importance, and furnishes
-us with the most important data for the construction of their pedigree.
-
-Finally, the palæontological records of creation are also of especial
-value in the case of these same Vertebrate animals; for their fossil
-remains belong for the most part to the bony skeleton, a system of
-organs which is of the utmost importance for understanding their general
-organization. It is true that here, as in all other cases, the fossil
-records are exceedingly imperfect and incomplete, but more important
-remains of extinct Vertebrate animals have been preserved in a fossil
-state, than of most other groups of animals; and single fragments
-frequently furnish the most important hints as to the relationship and
-the historical succession of the groups.
-
-The name of _Vertebrate Animals_ (Vertebrata), as I have already said,
-originated with the great Lamarck, who towards the end of the last
-century comprised under this name, Linnæus' four higher classes of
-animals, viz. Mammals, Birds, Amphibious animals, and Fishes, Linnæus'
-two lower classes, Insects and Worms, Lamarck contrasted to the
-Vertebrata as _Invertebrata_, later also called _Evertebrata_.
-
-The division of the Vertebrata into the four classes above named was
-retained also by Cuvier and his followers, and in consequence by many
-zoologists down to the present day. But in 1822 Blanville, the
-distinguished anatomist, found out by comparative anatomy--which Bär did
-almost at the same time from the ontogeny of Vertebrata--that Linnæus'
-class of Amphibious animals was an unnatural union of two very different
-classes. These two classes were separated as early as 1820, by Merrin,
-as two main groups of Amphibious animals, under the names of Pholidota
-and Batrachia. The _Batrachia_, which are at present (in a restricted
-sense) called Amphibious animals, comprise Frogs, Salamanders, gilled
-Salamanders, Cæcilia, and the extinct Labyrinthodonta. Their entire
-organization is closely allied to that of Fishes. The _Pholidota_, or
-Reptiles, on the other hand, are much more closely allied to Birds. They
-comprise lizards, serpents, crocodiles, and tortoises, and the groups of
-the mesolithic Dragons, Flying reptiles, etc.
-
-In conformity with this natural division of Amphibious animals into two
-classes, the whole tribe of Vertebrate animals was divided into two main
-groups. The first main group, containing Amphibious animals and Fishes,
-breathe throughout their lives, or in early life, by means of gills, and
-are therefore called _gilled Vertebrata_ (Branchiata, or Anallantoida).
-The second main group--Reptiles, Birds, and Mammals--breathe at no
-period of their lives through gills, but exclusively through lungs, and
-hence may appropriately be called Gill-less, or _Vertebrata with lungs_
-(Abranchiata, or Allantoida). However correct this distinction may be,
-still we cannot remain satisfied with it if we wish to arrive at a true
-natural system of the vertebrate tribe, and at a right understanding of
-its pedigree. In this case, as I have shown in my General Morphology, we
-are obliged to distinguish three other classes of Vertebrate animals, by
-dividing what has hitherto been regarded as the class of fishes into
-four distinct classes. (Gen. Morph. vol. ii. Plate VII. pp. 116-160.)
-
-The first and lowest of these classes comprises the _Skull-less_ animals
-(Acrania), or animals with _tubular hearts_ (Leptocardia), of which only
-one representative now exists, namely, the remarkable little Lancelet
-(Amphioxus lanceolatus). Nearly allied to this is the second class, that
-of the _Single-nostriled_ animals (Monorrhina), or _Round-mouthed_
-animals (Cyclostoma), which includes the Hags (Myxinoida) and Lampreys
-(Petromyzonta). The third class contains only the genuine Fish (Pisces):
-the Mud-fishes (Dipneusta) are added to these as a fourth class, and
-form the transition from Fish to Amphibious animals. This distinction,
-which, as will be seen immediately, is very important for the genealogy
-of the Vertebrate animals, increases the original number of Vertebrate
-classes from four to eight.
-
-In most recent times a ninth class of Vertebrata has been added to these
-eight classes. Gegenbaur's recently published investigations in
-comparative anatomy prove that the remarkable class of _Sea-dragons_
-(Halisauria), which have hitherto been included among Reptiles, must be
-considered quite distinct from these, and as a separate class which
-branched off from the Vertebrate stock, even before the Amphibious
-animals. To it belong the celebrated large Ichthyosauri and Plesiosauri
-of the oolitic and chalk periods, and the older Simosauri of the Trias
-period, all of which are more closely allied to Fish than to Amphibious
-animals.
-
-These nine classes of Vertebrate animals are, however, by no means of
-the same genealogical value. Hence we must divide them, as I have
-already shown in the Systematic Survey on p. 133, into four distinct
-main-classes or tribes. In the first place, the three highest classes,
-Mammals, Birds, and Reptiles, may be comprised as a natural main-class
-under the name of _Amnion animals_ (Amnionata). The _Amnion-less
-animals_ (Anamnionata), naturally opposed to them as a second
-main-class, include the four classes of Batrachians, Sea-dragons,
-Mud-fish, and Fishes. The seven classes just named, the Anamnionata as
-well as the Amnionata, agree among one another in numerous
-characteristics, which distinguish them from the two lowest classes
-(the single-nostriled and tubular-hearted animals). Hence we may unite
-them in the natural main group of _Double-nostriled_ animals
-(Amphirrhina). Finally, these Amphirrhina on the whole are much more
-closely related to those animals with round mouths or single nostrils
-than to the skull-less or tube-hearted animals. We may, therefore, with
-full justice class the single and double-nostriled animals into one
-principal main group, and contrast them as _animals with skulls_
-(Craniota), or _bulbular hearts_ (Pachycardia), to the one class of
-_skull-less animals_, or animals with _tubular hearts_. This
-classification of the Vertebrate animals proposed by me renders it
-possible to obtain a clear survey of the nine classes in their most
-important genealogical relations. The systematic relationship of these
-groups to one another may be briefly expressed by the following table.
-
-
-          A.
-  =Skull-less Animals=                                     1. Tubular hearts 1. Leptocardia
-      (+Acrania+)
-
-                      { _a._ Single nostriled
-                      {      animals                     { 2. Round-mouths   2. Cyclostoma
-          B.          {    _Monorrhina_                  {
-     =Animals with=   {
-       =Skulls=       { b. Double     {                  { 3. Fish           3. Pisces
-    (+Craniota+)      { nostriled     { I. Non-Amnionate { 4. Mud-fish       4. Dipneusta
-                      { animals       { Anamnia          { 5. Sea-dragons    5. Halisauria
-         or           {               {                  { 6. Batrachians    6. Amphibia
-                      { _Amphirrhina_ {
-     =Thick Hearts=   {               { II. Amnionate.   { 7. Reptiles       7. Reptilia
-    (+Pachycardia+)   {               { Amniota          { 8. Birds          8. Aves
-                      {               {                  { 9. Mammals        9. Mammalia
-
-
-The only one representative of the first class, the small _lanceolate
-fish_, or Lancelet (Amphioxus lanceolatus) (Plate XIII. Fig. _B_),
-stands at the lowest stage of organization of all the Vertebrate
-animals known to us. This exceedingly interesting and important animal,
-which throws a surprising light upon the older roots of our pedigree, is
-evidently the last of the Mohicans--the last surviving representative of
-a lower class of Vertebrate animals, very rich in forms, and very highly
-developed during the primordial period, but which unfortunately could
-leave no fossil remains on account of the absence of all solid skeleton.
-The Lancelet still lives widely distributed in different seas; for
-instance, in the Baltic, North Sea, and Mediterranean, where it
-generally lies buried in the sand on flat shores. The body, as the name
-indicates, has the form of a narrow lanceolate leaf, pointed at both
-extremities. When full grown it is about two inches long, of a white
-colour and semi-transparent. Externally, the little lanceolate animal is
-so little like a vertebrate animal that Pallas, who first discovered it,
-regarded it as an imperfect naked snail. It has no legs, and neither
-head, skull, nor brain. Externally, the fore end of the body can be
-distinguished from the hinder end only by the open mouth. But still the
-Amphioxus in its internal structure possesses those most important
-features, which distinguish all Vertebrate animals from all Invertebrate
-animals, namely, the spinal rod and spinal marrow. The _spinal rod_
-(Chorda dorsalis) is a straight, cylindrical, cartilaginous staff,
-pointed at both ends, forming the central axis of the internal skeleton,
-and the basis of the vertebral column. Directly above the spinal rod, on
-its dorsal side, lies the _spinal marrow_ (medulla spinalis), likewise
-originally a straight but internally hollow cord, pointed at both ends.
-This forms the principal piece and centre of the nervous system in all
-Vertebrate animals. (Compare above vol. i. p. 303.) In all Vertebrate
-animals without exception, man included, these important parts of the
-body during the embryological development out of the egg, originally
-begin in the same simple form, which is retained throughout life by the
-Amphioxus. It is only at a later period that the brain develops by the
-expansion of the fore end of the spinal marrow, and out of the spinal
-rod the skull which encloses the brain. As these two important organs do
-not develop at all in the Amphioxus, we may justly call the class
-represented by it, _Skull-less animals_ (Acrania), in opposition to all
-the others, namely, to the _animals with skulls_ (Craniota). The
-Skull-less animals are generally called _tubular-hearted_ (Leptocardia),
-because a centralized heart does not as yet exist, and the blood is
-circulated in the body by the contractions of the tubular blood-vessels
-themselves. The Skulled animals, which possess a centralized,
-thick-walled, bulb-shaped heart, ought then by way of contrast to be
-called _bulbular-hearted_ animals (Pachycardia).
-
-[Illustration: _Ascidia (A.) and Amphioxus (B.)_ Pl. XII.
-
-  E. Haeckel del.       Legesse sc.]
-
-Animals with skulls and central hearts evidently developed gradually in
-the later primordial period out of those without skulls and with tubular
-hearts. Of this the ontogeny of skulled animals leaves no doubt. But
-whence are these same skull-less animals derived? It is only very lately
-that an exceedingly surprising answer has been given to this important
-question. From Kowalewsky's investigations, published in 1867, on the
-individual development of the Amphioxus and the adhering Sea-squirts
-(Ascidia) belonging to the class of mantled animals (Tunicata), it has
-been proved that the ontogenies of these two entirely different looking
-animal-forms agree in the first stage of development in a most
-remarkable manner. The freely swimming larvæ of the Ascidians (Plate
-XII. Fig. _A_) develop the undeniable beginning of a spinal marrow (Fig.
-5 _g_) and of a spinal rod (Fig. 5 _c_), and this moreover in entirely
-the same way as does the Amphioxus. (Plate XIII. Fig. _B_.) It is true
-that in the Ascidians these most important organs of the Vertebrate
-animal-body do not afterwards develop further. The Ascidians take on a
-retrograde transformation, become attached to the bottom of the sea, and
-develop into shapeless lumps, which when looked upon externally would
-scarcely be supposed to be animals. (Plate XIII. Fig. _A_.) But the
-spinal marrow, as the beginning of the central nervous system, and the
-spinal rod, as the first basis of the vertebral column, are such
-important organs, so exclusively characteristic of Vertebrate animals,
-that we may from them with certitude infer the true blood relationship
-of Vertebrate with Tunicate animals. Of course we do not mean to say by
-this, that Vertebrate animals are derived from Tunicate animals, but
-merely that both groups have arisen out of a common root, and that the
-Tunicates, of all the Invertebrata, are the nearest blood relations of
-the Vertebrates. It is quite evident that genuine Vertebrate animals
-developed progressively during the primordial period (and the skull-less
-animals first) out of a group of worms, from which the degenerate
-Tunicate animals arose in another and a retrograde direction. (Compare
-the more detailed explanation of Plates XII. and XIII. in the Appendix.)
-
-Out of the Skull-less animals there developed, in the first instance, a
-second low class of Vertebrate animals, which still stands far below
-that of fish, and which is now represented only by the Hags (Myxinoida)
-and Lampreys (Petromyzonta). This class also, on account of the absence
-of all solid parts, could, unfortunately, as little as the Skull-less
-animals leave fossil remains. From its whole organization and ontogeny
-it is quite evident that it represents a very important intermediate
-stage between the Skull-less animals and Fishes, and that its few still
-existing members are only the last surviving remains of a probably very
-highly developed animal group which existed towards the end of the
-primordial period. On account of the curious mouth possessed by the Hags
-and Lampreys, which they use for sucking, the whole class is usually
-called _Round-mouthed_ animals (Cyclostoma). The name of
-_Single-nostriled_ animals (Monorrhina) is still more characteristic.
-For all Cyclostoma possess a simple, single nasal tube, whereas, in all
-other Vertebrate animals (with the exception of the Amphioxus) the nose
-consists of two lateral halves, a right and a left nostril. We are
-therefore enabled to comprise these latter (Anamnionata and Amnionata)
-under the heading, _double-nostriled_ animals (Amphirrhina). All the
-Amphirrhina possess a fully developed jaw-skeleton (upper and under
-jaw), whereas it is completely wanting in the Monorrhina.
-
-Apart also from the peculiar nasal formation, and the absence of jaws,
-the Single-nostriled animals are distinguished from those with double
-nostrils by many peculiarities. Thus they want the important sympathetic
-nervous system, and the spleen which the Amphirrhina possess. Of the
-swimming bladder, and the two pairs of legs--which all double-nostriled
-animals have, at least in their embryonic conditions--not a trace exists
-in the Single-nostriled animals, which is the case also in the
-Skull-less animals. Hence, we are surely justified in completely
-separating the Monorrhina, as we have separated the Skull-less animals,
-from the Fishes, with which they have hitherto been erroneously classed.
-
-[Illustration: _Ascidia (A.) and Amphioxus (B.)_ Pl. XIII.
-
-  E. Haeckel del.        Lagesse sc.]
-
-We owe our first accurate knowledge of the Monorrhina, or Cyclostoma, to
-the great zoologist, Johannes Müller of Berlin; his classical work on
-the "Comparative Anatomy of the Myxinoida" forms the foundation of our
-modern views on the structure of the Vertebrate animals. He
-distinguished two distinct groups among the Cyclostoma, which we shall
-consider as sub-classes.
-
-The first sub-class consists of the Hags (Hyperotreta, or Myxinoida).
-They live in the sea as parasites upon other fish, into whose skin they
-penetrate (Myxine, Bdellostoma). Their organ of hearing has only one
-annular canal, and their single nasal tube penetrates the palate. The
-second sub-class, that of Lampreys, or Prides (Hyperoartia, or
-Petromyzontia) is more highly developed. It includes the well-known
-Lamperns, or Nine-eyes, of our rivers (Petromyzon fluviatilis), with
-which most persons are acquainted. They are represented in the sea by
-the frequently larger marine or genuine Lampreys (Petromyzon marinus).
-The nasal tube of these single-nostriled animals does not penetrate the
-palate, and in the auricular organ there are two annular canals.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 4 Main-classes, 9 Classes, and 26 Sub-classes of Vertebrata._
-
-Gen. Morph. vol. ii. Plate VII. pp. 116-160.
-
-
-  ======================================================================================
-              I. =Skull-less= (+Acrania+), or =Tube-hearted= (+Leptocardia+).
-
-      Vertebrata without head, without skull and brain, without centralized heart.
-  --------------------------------------------------------------------------------------
-  1. =Skull-less=          I. Tube-hearted    {  1. Lancelet            1. Amphioxus
-     +Acrania+               _Leptocardia_    {
-  --------------------------------------------------------------------------------------
-
-  II. =Animals with skulls= (+Craniota+) and with =thick-walled hearts= (+Pachycardia+).
-       Vertebrata with head, with skull and brain, with centralized heart.
-
-  ======================================================================================
-     _Main-classes_     |    _Classes_       |      _Sub-classes_    | _Systematic Name_
-    _of the Skulled_    |   _of the_         |     _of the_          |     _of the_
-       _Animals._       | _Skulled Animals._ |   _Skulled Animals._  |  _Sub-classes._
-  --------------------------------------------------------------------------------------
-  2. =Single-Nostriled=  { II. Round mouths   {  2. Hags, or Mucous     2. Hyperotreta
-        +Monorrhina+    {   _Cyclostoma_     {       Fish                 (Myxinoida)
-                         {                    {  3. Lampreys, or        3. Hyperoartia
-                         {                    {       Pride                (Petromyzontia)
-
-
-                         {     III. Fish      {  4. Primæval fish       4. Selachii
-                         {      _Pisces_      {  5. Ganoid fish         5. Ganoides
-                         {                    {  6. Osseous fish        6. Teleostei
-                         {
-                         {  IV. Mud-fish      {  7. Mud-fish            7. Protopteri
-  3. =Non-amnionate=     {   _Dipneusta_      {
-                         {
-    +Anamnionata+        {                    {  8. Primæval            8. Simosauria
-                         {  V. Sea-dragons    {       dragons
-                         {    _Halisauri_     {  9. Snake-dragons       9. Plesiosauria
-                         {                    { 10. Fish-dragons       10. Ichthyosauria
-                         {
-                         { VI. Batrachians    { 11. Mailed Batrachians 11. Phractamphibia
-                         {    _Amphibia_      { 12. Naked Batrachians  12. Lissamphibia
-
-
-  4. =Amnion=            {   VII. Reptiles    { 13. Primary reptiles   13. Tocosauria
-    =Animals=            {    _Reptilia_      { 14. Lizards            14. Lacertilia
-  +Amnionata+            {                    { 15. Serpents           15. Ophidia
-                         {                    { 16. Crocodiles         16. Crocodilia
-                         {                    { 17. Tortoises          17. Chelonia
-                         {                    { 18. Flying reptiles    18. Pterosauria
-                         {                    { 19. Dragons            19. Dinosauria
-                         {                    { 20. Beaked reptiles    20. Anomodontia
-                         {
-                         {    VIII. Birds     { 21. Long-tailed        21. Saururæ
-                         {       _Aves_       { 22. Fan-tailed         22. Carinatæ
-                         {                    { 23. Bush-tailed        23. Ratitæ
-                         {
-                         {   IX. Mammals      { 24. Cloacal animals    24. Monotrema
-                         {    _Mammalia_      { 25. Pouched animals    25. Marsupialia
-                         {                    { 26. Placental animals  26. Placentalia
-
-        ----------------------------------------------------------------
-
-                                                       9. Mammals
-                                                         _Mammalia_
-                                       8. Birds              |
-                                         _Aves_              |
-                                            |                |
-                                       7. Reptiles           |
-                                          _Reptilia_         |
-                         5. Sea-dragons     |                |
-                          _Halisauria_      \-------v--------/
-                               |                    |
-  Osseous fish                 |              =Amnion Animals=
-  _Teleostei_    4. Mud-fish   |                +Amniota+
-      |            _Dipneusta_ |                    |
-      |               |        |                    |
-      |               |        |              6. Batrachians
-  Ganoid fish         |        |                 _Amphibia_
-   _Ganoidei_         |        |                    |
-      |               |        |                    |
-      |               \--------------v--------------/
-      |                              |
-      |           Vertebrate animals breathing through lungs
-      |                        _Amphipneumones_
-      |                              |
-      |                              |
-      \------------v-----------------/
-     Primæval fish      Selachii
-      3. Fishes         _Pisces_
-  =Double-nostriled=   +Amphirrhina+
-                   |                          2. Round-mouthed
-                   |                             _Cyclostoma_
-                   |                                  |
-                   |                                  |
-                   \--------------------v-------------/
-                   =Single-nostriled=       Monorrhina
-                   =Animals with skulls=    +Craniota+
-
-               1. Tube-hearted          |
-                 _Leptocardia_          |
-                       |                |
-                       |                |
-                       \---------v------/
-            _Ascidiæ_            |
-  Sea-barrels   |       =Skull-less Animals=
-  _Thaliacea_   |           +Acrania+
-      |         |       =Vertebrate Animals=
-      |         |          +Vertebrata+
-      \----v----/                |
-           |                     |
-  =Tunicate Animals=             |
-       +Tunicata+                |
-           |                     |
-           |                     |
-           \-----------v---------/
-                       |
-                     Worms
-                    _Vermes_
-
-
-All existing Vertebrate animals, with the exception of the Monorrhina
-and Amphioxus just mentioned, belong to the group which we designate as
-Double-nostriled animals (Amphirrhina). All these animals possess (in
-spite of the great variety in the rest of their forms) a nose consisting
-of two lateral halves, a jaw-skeleton, a sympathetic nervous system,
-three annular canals connected with the auricular sac, and a spleen.
-Further, all Double-nostriled animals possess a bladder-shaped expansion
-of the gullet, which, in Fish, has developed into the swimming bladder,
-but in all other Double-nostriled animals into lungs. Finally, in all
-Double-nostriled animals there exist in the youngest stage of growth the
-beginnings of two pairs of extremities, or limbs, a pair of fore legs,
-or breast fins, and a pair of hinder legs, or ventral fins. One of these
-pairs of legs sometimes degenerates (as in the case of eels, whales,
-etc.), or both pairs of legs (as in Cæciliæ and serpents) either
-degenerate or entirely disappear; but even in these cases there exists
-some trace of their original beginning in an early embryonic period, or
-the useless remains of them may be found in the form of rudimentary
-organs. (Compare above, vol. i. p. 13.)
-
-From all these important indications we may conclude with full assurance
-that all double-nostriled animals are derived from a single common
-primary form, which developed either directly or indirectly during the
-primordial period out of the Monorrhina. This primary form must have
-possessed the organs above mentioned, and also the beginning of a
-swimming bladder and of two pairs of legs or fins. It is evident, that
-of all still living double-nostriled animals, the lowest forms of sharks
-are most closely allied to this long since extinct, unknown, and
-hypothetical primary form, which we may call the Primary
-Double-nostriled animals (Proselachii). We may therefore look upon the
-group of primæval fish, or Selachii, to which the _Proselachii_ probably
-belonged, as a primary group, not only of the Fish class, but of the
-whole main-class of double-nostriled animals.
-
-The class of _Fish_ (Pisces) with which we accordingly begin the series
-of Double-nostriled animals, is distinguished from the other six classes
-of the series by the swimming bladder never developing into lungs, but
-acting only as a hydrostatic apparatus. Agreeing with this, we find that
-in fish the nose is formed by two blind holes in front of the mouth,
-which never pierce the palate so as to open into the cavity of the
-mouth. In the other six classes of double-nostriled animals, both
-nostrils are changed into air passages which pierce the palate, and thus
-conduct air to the lungs. Genuine fish (after the exclusion of the
-Dipneusta) are accordingly the only double-nostriled animals which
-exclusively breathe through gills and never through lungs. In accordance
-with this, they all live in water, and both pairs of their legs have
-retained the original form of paddling fins.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 7 Legions and 15 Orders of the Fishes._
-
-
- ---------------------------------------------------------------------------------
-  _Sub-classes_ |      _Legions_     |      _Orders_       |        _Examples_
-      _of_      |        _of_        |        _of_         |          _from_
-    _Fishes._   |      _Fishes._     |      _Fishes._      |       _the Orders._
- ---------------------------------------------------------------------------------
-                 {
-                 {                    {  1. Sharks            Sharks, dog-fish
-                 {   I. Transverse    {    _Squalacei_
-        A.       {       mouths       {  2. Rays              Spiked rays, electric
-    =Primæval=   {    _Plagiostomi_   {    _Rajacei_           rays, etc.
-      =Fish=     {
-    +Selachii+   {    II. Sea-Cats    {  3. Sea-Cats          Chimæra, Calorrhynchias
-                 {    _Holocephali_   {    _Chimæracei_
-
-
-                 {                    {  4. Buckler-heads     Cephalaspidæ, Placoderma,
-                 { III. Mailed Ganoid {    _Pamphracte_        etc.
-                 {        Fish        {  5. Sturgeons         Spoon-sturgeons, sturgeons,
-                 {     _Tabuliferi_   {    _Sturiones_         sterlet, etc.
-                 {
-                 {                    {  6. _Efulcri_         Double-finned
-         B.      { IV. Angular-scaled {  7. _Fulcrati_        Palæoniscus, bony pike,
-      =Ganoid=   {     Ganoid Fish    {                        etc.
-       =Fish=    {     _Rhombiferi_   {  8. _Semæopteri_      African finny pike, etc.
-     +Ganoides+  {
-                 {  V. Round-scaled   {  9. _Coeloscolopes_   Holoptychius, Coelacanthides,
-                 {     Ganoid Fish    {                        etc.
-                 {     _Cycliferi_    { 10. _Pycnoscolopes_   Coccolepida, Amiadæ,
-                                                               etc.
-
-                { VI. Osseous Fish   {
-                {    with an air     { 11. Herring species    Herrings, salmon, carp,
-                {   passage to the   {    _Thrissogenes_       etc.
-         C.     {      swimming      { 12. Eel species        Eels, snake eels, electric
-      =Osseous= {       bladder      {    _Enchelygenes_       eels, etc.
-       =Fish=   {     _Physostomi_   {
-    +Teleostei+ {
-                { VII.  Osseous Fish { 13. _Stichobranchii_   Perch, wrasse, turbot,
-                {    without an air  {                         etc.
-                {    passage to the  { 14. _Plectognathi_     Trunk fish, globe fish,
-                {       swimming     {                         etc.
-                {        bladder     { 15. _Lophobranchii_    Pipe fish, sea horses,
-                {     _Physoclisti_  {                         etc.
-
-        ----------------------------------------------------------------
-
-PEDIGREE OF THE NON-AMNIONATE CRANIOTA.
-
-
-  Plectognathi                                              Anura
-       |      Lophobranchia                     Peromela      |
-       |             |                              |         |
-       |             |                              |       Sozura
-       \-------v-----/            Labyrinthodonta   |         |
-               |                           |        |         |
-         Stichobranchia                    |        |         |
-         +Physoclisti+                     \--v-----/         |
-               |                              |               |
-  Enchelygenes |                          Ganocephala    Sozobranchia
-        |      |                        +Phractamphibia+ +Lissamphibia+
-        |      |                              |               |
-        \--v---/                              |               |
-           |                                  \-------v-------/
-           |                                          |
-      Thrissogenes                               +Amphibia+
-      +Physostomi+           Semæopteri               |
-      +Teleostei+                 |                   |
-           |                      |       Protopteri  |
-           |            Fulcrati  |           |       |            Plesiosauria
-     Pycnoscolopes          |     |           |       | Icthyosauria     |
-           |                |     |           |       |       |          |
-    Coeloscolopes        Efulcri  |           |       |       |          |
-      +Cycliferi+       +Rhombiferi+          |       |       |          |
-    (Cycloganoides)    (Rhomboganoides)       |       |       |          |
-           |                  |               |       |       |          |
-           \---------v--------/               |       |       \----v-----/
-                     |                   +Dipneusta+   |            |
-                Placoderma                    |       |        Simosauria
-   Sturiones         |                        |       |        +Halisauria+
-       |             |                        |       |            |
-  Cephalaspidæ       |       Rajacei          \-----------v--------/
-       |             |          |                         |
-       |             |          |                  Amphipneumona
-       \-----v-------/          |                         |
-             |                  |                         |
-         Pamphracti             |                         |
-        +Tabuliferi+            |                         |
-       (Placoganoides)          |   Chimæracei            |
-         +Ganoides+             |  +Holocephali+          |
-             |                  |       |                 |
-         Squalacei              |       |                 |
-             |                  |       |                 |
-             \--------v---------/       |                 |
-                      |                 |                 |
-                 +Plagiostomi+          |                 |
-                      |                 |                 |
-                      \-------------v---------------------/
-                                    |
-                                +Selachii+
-                                  +Fish+
-                              +Amphirrhina+
-                                    |             Cyclostoma
-                                    |            +Monorrhina+
-                                    |                 |
-                                    \-------v---------/
-                                            |
-                                        +Craniota+
-
-
-Genuine fish are divided into three distinct sub-classes, namely,
-Primæval fish, Ganoid fish, and Osseous fish. The oldest of these, where
-the original form has been most faithfully preserved, is that of the
-_Primæval fish_ (Selachii). Of these there still exist Sharks (Squali),
-and Rays (Rajæ), which are classed together as cross-mouthed fishes
-(Plagiostomi), and the strange and grotesquely formed Sea-cats, or
-_Chimæracei_ (Holocephali). These primary fish of the present day, which
-are met with in all seas, are only poor remains of the prevailing animal
-groups, rich in forms, which the Selachii formed in the earlier periods
-of the earth's history, and especially during the palæolithic period.
-Unfortunately all Primæval fish possess a cartilaginous, never a
-completely osseous skeleton, which is but little, if at all, capable of
-being petrified. The only hard parts of the body which could be
-preserved in a fossil state, are the teeth and fin-spikes. These are
-found in the older formations in such quantities, varieties, and sizes,
-that we may, with certainty, infer a very considerable development of
-Primæval fish in those remote ages. They are even found in the Silurian
-strata, which contain but few remains of other Vertebrata, such as
-Enamelled fish (and these only in the most recent part, that is, in the
-upper Silurian). By far the most important and interesting of the three
-orders of Primæval fish are Sharks; of all still living double-nostriled
-animals, they are probably most closely allied to the original primary
-form of the whole group, namely, to the Proselachii. Out of these
-Proselachii, which probably differed but little from genuine Sharks,
-Enamelled fish, and the present Primæval fish, in all probability,
-developed in one direction, and the Dipneusta, Sea-dragons, and Amphibia
-in another.
-
-The _Ganoid_, or _Enamelled fish_ (Ganoides), in regard to their anatomy
-stand midway between the Primæval and the Osseous fish. In many
-characteristics they agree with the former, and in many others with the
-latter. Hence, we infer that genealogically they form the transition
-from Primæval to Osseous fish. The Ganoids are for the most part
-extinct, and more nearly so than the Primæval fish, whereas they were
-developed in great force during the entire palæolithic and mesolithic
-periods. Ganoid fish are divided into three legions according to the
-form of their external covering, namely, Mailed, Angular-scaled, and
-Round-scaled. The _Mailed Ganoid fish_ (Tabuliferi) are the oldest, and
-are directly allied to the Selachii, out of which they originated.
-Fossil remains of them, though rare, are found even in the upper
-Silurian (Pteraspis ludensis of the Ludlow strata). Gigantic species of
-them, coated with strong bony plates, are found in the Devonian system.
-But of this legion there now lives only the small order of Sturgeons
-(Sturiones), including the Spade-sturgeons (Spatularidæ), and those
-Sturgeons (Accipenseridæ) to which belong, among others, the Huso, which
-yields isinglass, or sturgeon's sound, and the Caviar-sturgeon, whose
-eggs we eat in the shape of caviar, etc. Out of the mailed Ganoid fish,
-the angular and round-scaled ones probably developed as two diverging
-branches. The _Angular-scaled Ganoid fish_ (Rhombiferi)--which can be
-distinguished at first sight from all other fish by their square or
-rhombic scales--are at present represented only by a few survivors,
-namely, the Finny Pike (Polypterus) in African rivers (especially the
-Nile), and by the Bony Pike (Lepidosteus) in American rivers. Yet during
-the palæolithic and the first half of the mesolithic epochs this legion
-formed the most numerous group of fishes. The third legion, that of
-_Round-scaled Ganoid fish_ (Cycliferi), was no less rich in forms, and
-lived principally during the Devonian and Coal periods. This legion, of
-which the Bald Pike (Amia), in North American rivers, is the only
-survivor, was especially important, inasmuch as the third sub-class of
-fish, namely, Osseous fish, developed out of it.
-
-_Osseous fish_ (Teleostei) include the greater portion of the fish of
-the present day. Among these are by far the greater portion of marine
-fish, and all of our fresh-water fish except the Ganoid fish just
-mentioned. This class is distinctly proved by numerous fossils to have
-arisen about the middle of the Mesolithic epoch out of Ganoid fish, and
-moreover out of the Round-scaled, or Cycliferi. The Thrissopidæ of the
-Oolitic period (Thrissops, Leptolepis, Tharsis), which are most closely
-allied to the herrings of the present day, are probably the oldest of
-all Osseous fish, and have directly arisen out of Round-scaled Ganoid
-fish, closely allied to the existing Amia. In the older Osseous fish of
-the legion called _Physostomi_, as also in the Ganoides, the swimming
-bladder throughout life was connected with the throat by a permanent air
-passage (a kind of windpipe). This is still the case with all the fish
-belonging to this legion, namely, with herrings, salmon, carp, shad,
-eels, etc. However, during the chalk period this air passage, in some of
-the Physostomi, became constricted and closed, and the swimming bladder
-was thus completely separated from the throat. Hence there arose a
-second legion of Osseous fish, the _Physoclisti_, which did not attain
-their actual development until the tertiary epoch, and soon far
-surpassed the Physostomi in variety. To this legion belong most of the
-sea fish of the present day, especially the large families of the
-Turbot, Tunny, Wrasse, Crowfish, etc., further, the Lock-jaws
-(Plectognathi), Trunk fish, and Globe-fish and the Bushy-gills
-(Lophobranchi), viz., Pipe-fish, and Sea-horses. There are, however,
-only very few Physoclisti among our river fish, for instance, Perch and
-Sticklebacks; the majority of river fish are Physostomi.
-
-Midway between genuine Fish and Amphibia is the remarkable class of
-_Mud-fish_, or _Scaly Sirens_ (Dipneusta, or Protopteri). There now
-exist only a few representatives of this class, namely, the American
-Mud-fish (Lepidosiren paradoxa) in the region of the river Amazon, and
-the African Mud-fish (Protopterus annectens) in different parts of
-Africa. A third large Salamander-fish (Ceratodus Fosteri) has lately
-been discovered in Australia. During the dry season, that is in summer,
-these strange animals bury themselves in a nest of leaves in the dry
-mud, and then breathe air through lungs like the Amphibia. But during
-the wet season, in winter, they live in rivers and bogs, and breathe
-water through gills like fish. Externally, they resemble fish of the eel
-kind, and are like them covered with scales; in many other
-characteristics also--in their internal structure, their skeleton,
-extremities, etc.--they resemble Fish more than Amphibia. But in certain
-features they resemble the Amphibia, especially in the formation of
-their lungs, nose, and heart. There is consequently an endless dispute
-among zoologists, as to whether the Mud-fish are genuine Fish or
-Amphibia. Distinguished zoologists have expressed themselves in favour
-of both opinions. But in fact, owing to the complete blending of
-characteristics which they present, they belong neither to the one nor
-to the other class, and are probably most correctly dealt with as a
-special class of Vertebrata, forming the transition between Fishes and
-Amphibians. The still living Dipneusta are probably the last surviving
-remains of a group which was formerly rich in forms, but has left no
-fossil traces on account of the want of a solid skeleton. In this
-respect, these animals are exactly like the Monorrhina and the
-Leptocardia. However, teeth are found in the Trias which resemble those
-of the living Ceratodus. Possibly the extinct Dipneusta of the
-palæolithic period, which developed in the Devonian epoch out of
-primæval fish, must be looked upon as the primary forms of the Amphibia,
-and thus also of all higher Vertebrata. At all events the unknown forms
-of transition--from Primæval fish to Amphibia--were probably very like
-the Dipneusta.
-
-A very peculiar class of Vertebrate animals, long since extinct, and
-which appears to have lived only during the secondary epoch, is formed
-by the remarkable _Sea-dragons_ (Halisauria, or Enaliosauria, also
-called Nexipoda, or Swimming-footed animals). These formidable animals
-of prey inhabited the mesolithic oceans in great numbers, and were of
-most peculiar forms, sometimes from thirty to forty feet in length. From
-many and excellently preserved fossil remains and impressions, both of
-the entire body of Sea-dragons as well as of single parts, we have
-become very accurately acquainted with the structure of their bodies.
-They are usually classed among Reptiles, whilst some anatomists have
-placed them in a much lower rank, as directly allied to Fish.
-Gegenbaur's recently published investigations, which place the structure
-of their limbs in a true light, have led to the surprising conclusion
-that the Sea-dragons form quite an isolated group, differing widely both
-from Reptiles and Amphibia as well as from Fish. The skeleton of their
-four legs, which are transformed into short, broad, paddling fins (like
-those of fish and whales) furnishes us with a clear proof that the
-Halisauria branched off from the main-stock of Vertebrata at an earlier
-period than the Amphibia. For Amphibia, as well as the three higher
-classes of Vertebrata, are all derived from a common primary form, which
-possessed only _five_ toes or fingers on each leg. But the Sea-dragons
-have (either distinctly developed or in a rudimentary condition as parts
-of the skeleton of the foot) more than five fingers, as have also the
-Selachians or Primæval fish. On the other hand, they breathed air
-through lungs, like the Dipneusta, although they always swam about in
-the sea. They, therefore, perhaps, in conjunction with the Dipneusta,
-branched off from the Selachii, but did not develop into higher
-Vertebrata; they form an extinct lateral line of the pedigree, which has
-died out.
-
-The more accurately known Sea-dragons are classed into three orders,
-distinct enough one from the other, namely, _Primæval Dragons_, _Fish
-Dragons_, and _Serpent Dragons_. The _Primæval Dragons_ (Simosauria) are
-the oldest Sea-dragons, and lived only during the Trias period. The
-skeletons of many different genera of them are met with in the German
-limestone known as "Muschel-kalk." They seem upon the whole to have been
-very like the Plesiosauria, and are, consequently, sometimes united with
-them into one order as Sauropterygia. The _Serpent Dragons_
-(Plesiosauria) lived in the oolitic and chalk periods together with the
-Ichthyosauria. They were characterised by an uncommonly long thin neck,
-which was frequently longer than the whole body, and carried a small
-head with a short snout. When their arched neck was raised they must
-have looked very like a swan; but in place of wings and legs they had
-two pairs of short, flat, oval-paddling fins.
-
-The body of the _Fish Dragons_ (Ichthyosauria) was of an entirely
-different form; these animals may be opposed to the two preceding orders
-under the name of Fish-finners (Ichthyopterygia). They possessed a very
-long extended body, like a fish, and a heavy head with an elongated,
-flat snout, but a very short neck. Externally, they were probably very
-like porpoises. Their tail was very long, whereas it was very short in
-the members of the preceding orders. Also both pairs of paddling fins
-are broader and show very different structure from that seen in the
-other two orders. Probably the Fish Dragons and Serpent Dragons
-developed as two diverging branches out of the Primæval Dragons; but it
-is also possible that the Plesiosauria alone originated out of the
-Simosauria, and that the Ichthyosauria were lower off-shoots from the
-common stock. At all events, they must all be directly, or indirectly
-derived from the Selachii, or Primæval fish.
-
-The succeeding classes of Vertebrata, the _Amphibia_ and the _Amniota_
-(Reptiles, Birds, and Mammals), owing to the characteristic structure
-which they all exhibit of five toes to each foot, may all be derived
-from a common primary form, which originated from the Selachii, and
-which possessed five toes on each of its four limbs. When we find a less
-number of toes than five, we can show that the missing ones must have
-been lost in the course of time by adaptation. The oldest known
-Vertebrata with five toes are the _Batrachias_ (Amphibia). We divide
-this class into two sub-classes, namely, mailed Batrachians and naked
-Batrachians, the first of which is distinguished by the body being
-covered with bony plates or scales.
-
-The first and elder sub-class of Amphibia consists of the _Mailed
-Batrachians_ (Phractamphibia), the oldest land living Vertebrata of
-which fossil remains exist. Well-preserved fossil remains of them occur
-in the coal, especially of those with _Enamelled heads_ (Ganocephala),
-which are most closely allied to fish, namely, the Archegosaurus of
-Saarbruck, and the Dendrerpeton of North America. There then follow at a
-later period the gigantic _Labyrinth-toothed animals_ (Labyrinthodonta),
-which are represented in the Permian system by Zygosaurus, but at a
-later period, more especially in the Trias, by Mastodonsaurus,
-Trematosaurus, Capitosaurus, etc. The shape of these formidable
-rapacious animals seems to have been between that of crocodiles,
-salamanders, and frogs, but in their internal structure they were more
-closely related to the two latter, while by their solid coat of mail,
-formed of strong bony plates, they resembled the first animals. These
-gigantic mailed Batrachians seem to have become extinct towards the end
-of the Triassic period. No fossil remains of mailed Batrachia are known
-during the whole of the subsequent periods. However, the still living
-blind Snakes, or _Cæciliæ_ (Peromela)--small-scaled Phractamphibia of
-the form and the same mode of life as the earth-worm--prove that this
-sub-class continued to exist, and never became completely extinct.
-
-The second sub-class of Amphibia, the _naked Batrachia_ (Lissamphibia),
-probably originated even during the primary and secondary epochs,
-although fossil remains of them are first found in the tertiary epoch.
-They are distinguished from mailed Batrachia by possessing a naked
-smooth, and slimy skin, entirely without scales or coat of mail. They
-probably developed either out of a branch of the Phractamphibia, or out
-of the same common root with them. The ontogeny of the three still
-living orders of naked Batrachia--the gilled Batrachia, tailed
-Batrachia, and frog Batrachia--distinctly repeats the historical course
-of development of the whole sub-class. The oldest forms are the gilled
-Batrachia (Sozobranchia), which retain throughout life the original
-primary form of naked Batrachia, and possess a long tail, together with
-water-breathing gills. They are most closely allied to the Dipneusta,
-from which, however, they differ externally by the absence of the coat
-of scales. Most gilled Batrachia live in North America: among others of
-the class is the Axolotl, or Siredon, already mentioned. (Compare above,
-vol. i. p. 241.) In Europe the order is only represented by one form,
-the celebrated "Olm" (Proteus anguinus), which inhabits the grotto of
-Adelsberg and other caves in Carinthia, and which, from living in the
-dark, has acquired rudimentary eyes which can no longer see (vol. i. p.
-13). The order of Tailed Batrachia (Sozura) have developed out of the
-gilled Batrachia by the loss of external gills; the order includes our
-black and yellow spotted land Salamander (Salamandra maculata), and our
-nimble aquatic Salamanders (Tritons). Many of them--for instance, the
-celebrated giant Salamanders in Japan (Cryptobranchus Japonicus)--still
-retain the gill-slits, although the gills themselves have disappeared.
-All of them, however, retain the tail throughout life. Tritons
-occasionally--when forced to remain in water always--retain their gills,
-and thus remain at the same stage of development as gilled Batrachia.
-(Compare above, vol. i. p. 241.) The third order, the _tailless_ or
-_frog-like Batrachia_ (Anura), during their metamorphosis, not only lose
-their gills, with which in early life (as so-called tadpoles) they
-breathe in water, but also the tail with which they swim about. During
-their ontogeny, therefore, they pass through the course of development
-of the whole sub-class, they being at first _Gilled Batrachia_, then
-_Tailed Batrachia_, and finally _Frog-like Batrachia_. The inference
-from this is evidently, that _Frog-like Batrachia_ developed at a later
-period out of _Tailed Batrachia_, as the latter had developed out of
-_Gilled Batrachia_ which originally existed alone.
-
-In passing from the Amphibia to the next class of Vertebrata, namely,
-Reptiles, we observe a very considerable advance in the progress of
-organization. All the double-nostriled animals (Amphirrhina) up to this
-time considered, and more especially the two larger classes of Fish and
-Batrachia, agree in a number of important characteristics, which
-essentially distinguish them from the three remaining classes of
-Vertebrata--Reptiles, Birds, and Mammals. During the embryological
-development of these latter, a peculiarly delicate covering, the _first
-foetal membrane_, or _amnion_, which commences at the navel, is formed
-round the embryo; this membrane is filled with the amnion-water, and
-encloses the embryo or germ in the form of a bladder. On account of this
-very important and characteristic formation, we may comprise the three
-most highly developed classes of Vertebrata under the term
-_Amnion-animals_ (Amniota). The four classes of double-nostriled animals
-which we have just considered, in which the amnion is wanting (as is the
-case in all lower Vertebrate animals, single-nostriled and skull-less
-animals), may on the other hand be opposed to the others as _amnion-less
-animals_ (Anamnia).
-
-The formation of the foetal membrane, or amnion, which distinguishes
-reptiles, birds, and mammals from all other Vertebrata, is evidently a
-very important process in their ontogeny, and in the phylogeny which
-corresponds with it. It coincides with a series of other processes,
-which essentially determine the higher development of Amnionate animals.
-The first of these important processes is the _total loss of gills_, for
-which reason the Amniota, under the name of _Gill-less animals_
-(Ebranchiata), were formerly opposed to all other Vertebrate animals
-which breathed through gills (Branchiata). In all the Vertebrate already
-discussed, we found that they either always breathed through gills, or
-at least did so in early life, as in the case of Frogs and Salamanders.
-On the other hand, we never meet with a Reptile, Bird, or Mammal which
-at any period of its existence breathes through gills, and the
-gill-arches and openings which do exist in the embryos, are, during the
-course of the ontogeny, changed into entirely different structures,
-viz., into parts of the jaw-apparatus and the organ of hearing. (Compare
-above, vol. i. p. 307.) All Amnionate animals have a so-called cochlea
-in the organ of hearing, and a "round window" corresponding with it.
-These parts are wanting in the Amnion-less animals; moreover, their
-skull lies in a straight line with the axis of the vertebral column. In
-Amniotic animals the base of the skull appears bent in on the abdominal
-side, so that the head sinks upon the breast. (Plate III. Fig. _C_, _D_,
-_G_, _H_.) The organs of tears at the side of the eye also first develop
-in the Amniota.
-
-The question now is, When did this important advance take place in the
-course of the organic history of the earth? When did the common ancestor
-of all Amniota develop out of a branch of the Non-amniota, to wit, out
-of the branch of the Amphibia?
-
-To this question, the fossil remains of Vertebrata do not give us a very
-definite, but still they do give an approximate, answer. For with the
-exception of two lizard-like animals found in the Permian system (the
-Proterosaurus and Rhopalodon), all the fossil remains of Amniota, as yet
-known, belong to the _secondary_, _tertiary_, and _quaternary epochs_.
-With regard to the two Vertebrata just named, it is still doubtful
-whether they are genuine reptiles, or perhaps Amphibia of the salamander
-kind. Their skeleton alone is known to us, and even this not perfectly.
-Now as we know nothing of the characteristic features of their soft
-parts, it is quite possible that the Proterosaurus and Rhopalodon were
-non-amnionate animals more closely allied to Amphibia than to Reptiles;
-possibly they belonged to the transition form between the two classes.
-But, on the other hand, as undoubted fossil remains of Amniota have been
-found as early as the Trias, it is probable that the _main class of
-Amniota_ first developed in the Trias, that is, in the beginning of the
-Mesolithic epoch. As we have already seen, this very period is evidently
-one of the most important turning points in the organic history of the
-earth. The palæolithic fern forests were then replaced by the pine
-forests of the Trias period; important transformations then took place
-in many of the classes of Invertebrata. Articulated marine lilies
-(Colocrina) developed out of the plated ones (Phatnocrina.) The
-Autechinidæ, or sea-urchins with only twenty rows of plates, took the
-place of the palæolithic Palechinidæ, the sea-urchins with more than
-twenty rows of plates. The Cystideæ, Blastoideæ, Trilobita, and other
-characteristic groups of Invertebrata of the primary period became
-extinct. It is no wonder that transforming conditions of adaptation
-powerfully influenced the Vertebrate tribes also in the beginning of the
-Trias period, and caused the origin of Amniotic animals.
-
-If, however, the two Lizard and Salamander-like animals of the Permian
-system, the Proterosaurus and Rhopalodon, are considered genuine
-Reptiles, and consequently the most ancient Amniota, then the origin of
-this main class must necessarily have taken place in the preceding
-period, towards the end of the primary, namely, in the Permian period.
-However, all other remains of Reptiles, which were formerly believed to
-have been found in the Permian and the Coal system, or even in the
-Devonian system, have been proved to be either not remains of Reptiles
-at all, or to belong to a more recent date (for the most part to the
-Trias). (Compare Plate XIV.)
-
-The common hypothetical primary form of all Amniotic animals, which we
-may call _Protamnion_, and which was possibly nearly related to the
-Proterosaurus, very probably stood upon the whole midway between
-salamanders and lizards, in regard to its bodily formation. Its
-descendants divided at an early period into two different lines, one of
-which became the common primary form of Reptiles and Birds, the other
-the primary form of Mammals.
-
-Of all the three classes of Amniota, _Reptiles_ (Reptilia, or Pholidota,
-also called Sauria in the widest sense), remain at the lowest stage of
-development, and differ least from their ancestors, the Amphibia. Hence
-they were formerly universally included among them, although their whole
-organization is much more like that of Birds than Amphibia. There now
-exist only four orders of Reptiles, namely,--Lizards, Serpents,
-Crocodiles, and Tortoises. They, however, form but a poor remnant of the
-exceedingly various and highly developed host of Reptiles which lived
-during the Mesolithic, or Secondary epoch, and predominated over all
-other Vertebrata. The immense development of Reptiles during the
-Secondary epoch is so characteristic that we could as well name it after
-those animals as after the Gymnosperms (p. 111). Twelve of the
-twenty-seven sub-orders, given on the accompanying table, and four of
-the eight orders, belong exclusively to the secondary period. These
-mesolithic groups are marked by an asterisk. All the orders, with the
-exception of Serpents, are found fossilized even in the Jura and Trias
-periods.
-
-[Illustration: _Pl. XIV._
-
-  [Horizontal axis:]
-  Branches,
-  Classes,
-  and Sub-Classes,
-  of the Vertebrate
-  Stem.
-
-  Prochordata
-  Evertebrate
-  Forefathers
-  of the
-  Vertebrate
-
-  Skull-less
-  (Acrania)
-  or
-  Tube-hearted
-  Fish,
-  (Leptocardia)
-
-  Single
-  nostrilled
-  (Monorrhina)
-  or
-  Round-mouthed
-  Fishes
-  (Cyclostoma)
-
-  Anamnia { Paired-nostrilled forms or Amphirrhina
-          { with gills, without Amnion.
-    Fish, Pisces
-
-      Primeval
-      Fish,
-      Selachii.
-
-      Enamelled
-      Fish,
-      Ganoides.
-
-      Bony
-      Fish,
-      Teleostei.
-
-    Mud
-    Fish,
-    Dipneusta.
-
-    Sea-Dragons,
-    Halisauria.
-
-    Frogs and
-    Newts,
-    Amphibia.
-
-  Amniota { Paired nostrilled or Amphirrhina
-          { with Amnion, without gills.
-
-    Reptiles, Reptilia.
-
-      Primæval
-      Reptiles,
-      Tocosauria.
-
-      Lizards,
-      Lacertilia.
-
-      Snakes,
-      Ophidia.
-
-      Crocodiles,
-      Crocodilia.
-
-      Tortoises,
-      Chelonia.
-
-      Flying
-      Reptiles,
-      Pterosauria.
-
-      Dragons,
-      Dinosauria.
-
-      Billed
-      Reptiles,
-      Anomodontia.
-
-    Birds,
-    Aves.
-
-    Suckling animals, Mammalia.
-
-      Billed
-      Animals,
-      Monotrema.
-
-      Pouched
-      Animals,
-      Marsupialia.
-
-      Placental
-      Animals,
-      Placentalia.
-
-  [Vertical axis:]
-  Cenolithic or
-  Tertiary Epoch.
-
-    Pliocene
-    Age.
-
-    Miocene
-    Age.
-
-    Eocene
-    Age.
-
-  Mesolithic or
-  Secondary Epoch.
-
-    Chalk
-    Period.
-
-    Jurassic
-    Period.
-
-    Triassic
-    Period.
-
-  Palæolithic or
-  Primary Epoch.
-
-    Permian
-    Period.
-
-    Coal
-    Period.
-
-    Devonian
-    Period.
-
-  Archilithic or
-  Primordial Epoch.
-
-    Silurian
-    Period.
-
-    Cambrian
-    Period.
-
-    Laurentian
-    Period.
-
-  [Legend:]
-  Single or
-  MONOPHYLETIC PEDIGREE
-  of the Stem of the
-  BACK-BONED ANIMALS
-  Based on Palæontology.
-
-  Relative lengths of the 5
-  Epochs in per centages.
-
-  Quarternary Epoch      0.5
-  Tertiary Epoch         2.3
-  Secondary Epoch       11.5
-  Primary Epoch         32.1
-  Primordial Epoch      53.6
-                      ------
-              _Total_  100.0]
-
-In the first order, that of _Primary Reptiles_, or _Primary Creepers_
-(Tocosauria), we class the extinct _Thecodontia_ of the Trias, together
-with those Reptiles which we may look upon as the common primary form of
-the whole class. To the latter, which we may call _Primæval Reptiles_
-(Proreptilia), the Proterosaurus of the Permian system very probably
-belongs. The seven remaining orders must be considered as diverging
-branches, which have developed in different directions out of that
-common primary form. The Thecodontia of the Trias, the only positively
-known fossil forms of Tocosauria, were Lizards which seem to have been
-like the still living monitor lizards (Monitor, Varanus).
-
-
-SYSTEMATIC SURVEY
-
-_Of the 8 Orders and 27 Sub-orders of Reptiles._
-
-(Those groups marked with * became extinct even during the Secondary
-Period.)
-
-  -----------------------------------------------------------------------------------
-                     |     _Sub-orders_       | _Systematic Name_  |  _A Generic Name_
-      _Orders_       |         _of_           |     _of the_       |        _as_
-   _of Reptiles._    |      _Reptiles._       |   _Sub-orders._    |    _an example._
-  -----------------------------------------------------------------------------------
-  I. =Primary=       {  1. Primæval reptiles  1. Proreptilia       * (Proterosaurus?)
-     =Reptiles=      {
-   +Tocosauria+      {  2.                    2. Thecodontia       * Palæosaurus
-
-                     {  3. Cleft-tongued      3. Fissilingues        Monitor
-                     {  4. Thick-tongued      4. Crassilingues       Iguana
-  II. =Lizards=      {  5. Short-tongued      5. Brevilingues        Anguis
-   +Lacertilia+      {  6. Ringed lizards     6. Glyptodermata       Amphisbæna
-                     {  7. Chameleons         7. Vermilingues        Chamæleo
-
-                     {  8. Adders             8. Aglyphodonta        Coluber
-                     {  9. Tree serpents      9. Opisthoglypha       Dipsas
-  III. =Serpents=    { 10.                   10. Proteroglypha       Hydrophis
-       +Ophidia+     { 11. Vipers            11. Solenoglypha        Vipera
-                     { 12. Worm serpents     12. Opoterodonta        Typhlops
-
-                     { 13. Amphicoela        13. Teleosauria       * Teleosaurus
-  IV. =Crocodiles=   { 14. Opisthocoela      14. Steneosauria      * Steneosaurus
-   +Crocodilia+      { 15. Prosthocoela      15. Alligatores         Alligator
-
-                     { 16. Sea tortoises     16. Thalassita          Chelone
-   V. =Tortoises=    { 17. River tortoises   17. Potamita            Trionyx
-   +Chelonia+        { 18. Marsh tortoises   18. Elodita             Emys
-                     { 19. Land tortoises    19. Chersita            Testudo
-
-                     { 20. Long-tailed       20. Rhamphorhynchi    * Rhamphorhynchus
-   VI. =Flying=      {    Flying lizards
-    =Reptiles=       { 21. Short-tailed      21. Pterodactyli      * Pterodactylus
-  +Pterosauria+*     {    Flying lizards
-
-                     { 22. Giant dragons     22. Harpagosauria     * Megalosaurus
-  VII. =Dragons=     { 23. Elephantine       23. Therosauria       * Iguanodon
-  +Dinosauria+*      {      dragons
-
-                     { 24. Dog-toothed       24. Cynodontia        * Dicynodon
-  VIII. =Beaked=     { 25. Toothless         25. Cryptodontia      * Udenodon
-  =Reptiles=         { 26. Kangaroo reptiles 26. Hypsosauria       * Compsognathus
-  +Anomodontia+*     {
-                     { 27. Bird reptiles     27. Tocornithes       * (Tocornis)
-
-
-Of the four orders of reptiles now existing, and which, moreover, have
-alone represented the class since the beginning of the tertiary epoch,
-that of _Lizards_ (Lacertilia) is probably most closely allied to the
-extinct Primary Reptiles, and especially through the monitors already
-named. The class of _Serpents_ (Ophidia) developed out of a branch of
-the order of lizards, and this probably not until the beginning of the
-tertiary epoch. At least we at present only know of fossil remains of
-serpents from the tertiary strata. _Crocodiles_ (Crocodilia) existed
-much earlier; the Teleosauria and Steneosauria belonging to the class
-are found fossil in large quantities even in the Jura; but the still
-living alligators are first met with in a fossil state in the chalk and
-tertiary strata. The most isolated of the four existing orders of
-reptiles consists of the remarkable group of _Tortoises_ (Chelonia);
-fossils of these strange animals are first met with in the Jura. In some
-characteristics they are allied to Amphibia, in others, to Crocodiles,
-and by certain peculiarities even to Birds, so that their true position
-in the pedigree of Reptiles is probably far down at the root. The
-extraordinary resemblance of their embryos to Birds, manifested even at
-later stages of the ontogenesis, is exceedingly striking.
-
-The four extinct orders of Reptiles show among one another, and, with
-the four existing orders just mentioned, such various and complicated
-relationships, that in the present state of our knowledge we are obliged
-to give up the attempt at establishing their pedigree. The most
-deviating and most curious forms are the _Flying Reptiles_
-(Pterosauria); flying lizards, in which the extremely elongated fifth
-finger of the hand served to support an enormous flying membrane. They
-probably flew about, in the secondary period, much in the same way as
-the bats of the present day. The smallest flying lizards were about the
-size of a sparrow; the largest, however, with a breadth of wing of more
-than sixteen feet, exceeded the largest of our living flying birds in
-stretch of wing (condor and albatross). Numerous fossil remains of them,
-of the long-tailed Rhamphorhynchia and of the short-tailed Pterodactylæ
-are found in all the strata of the Jura and Chalk periods, but in these
-only.
-
-Not less remarkable and characteristic of the Mesolithic epoch was the
-group of _Dragons_ (Dinosauria, or Pachypoda). These colossal reptiles,
-which attained a length of more than fifty feet, are the largest
-inhabitants of the land which have ever existed on our globe; they lived
-exclusively in the secondary epoch. Most of their remains are found in
-the lower cretaceous system, more especially in the Wealden formations
-of England. The majority of them were fearful beasts of prey (the
-Megalosaurus from twenty to thirty, the Pelorosaurus from forty to fifty
-feet in length). The Iguanodon, however, and some others lived on
-vegetable food, and probably played a part in the forests of the chalk
-period similar to that of the unwieldy but smaller elephants,
-hippopotami, and rhinoceroses of the present day.
-
-The _Beaked Reptiles_ (Anomodontia), likewise also long since extinct,
-but of which very many remarkable remains are found in the Trias and
-Jura, were perhaps closely related to the Dragons. Their jaws, like
-those of most Flying Reptiles and Tortoises, had become changed into a
-beak, which either possessed only degenerated rudimentary teeth, or no
-teeth at all. In this order, if not in the preceding one, we must look
-for the primary parents of the bird class, which we may call Bird
-Reptiles (Tocornithes). Probably very closely related to them was the
-curious, kangaroo-like Compsognathus from the Jura, which in very
-important characteristics already shows an approximation to the
-structure of birds.
-
-The class of _Birds_ (Aves), as already remarked, is so closely allied
-to Reptiles in internal structure and by embryonal development, that
-they undoubtedly originated out of a branch of this class. Even a glance
-at Plates II. and III. will show that the embryos of birds at a time
-when they already essentially differ from the embryos of Mammals, are
-still scarcely distinguishable from those of Tortoises and other
-Reptiles. The cleavage of the yolk is partial in the case of Birds and
-Reptiles, in Mammals it is total. The red blood-cells of the former
-possess a kernel, those of the latter do not. The hair of Mammals
-develops in closed follicles in the skin, but the feathers of birds and
-also the scales of reptiles develop in hillocks on the skin. The lower
-jaw of the latter is much more complicated than that of Mammals; the
-latter do not possess the quadrate bone of the former. Whereas in
-Mammals (as in the case of Amphibia) the connection between the skull
-and the first neck vertebra is formed by two knobbed joints, or
-condyles, in Birds and Reptiles those have become united into a single
-condyle. The two last classes may therefore justly be united into one
-group as Monocondylia, and contrasted to Mammals, or Dicondylia.
-
-The deviation of Birds from Reptiles, in any case, first took place in
-the mesolithic epoch, and this moreover probably during the Trias. The
-oldest fossil remains of birds are found in the upper Jura
-(Archæopteryx). But there existed, even in the Trias period, different
-Saurians (Anomodonta) which in many respects seem to form the transition
-from the Tocosauria to the primary ancestors of Birds, the hypothetical
-Tocornithes. Probably these Tocornithes were scarcely distinguishable
-from other beaked lizards in the system, and were closely related to the
-kangaroo-like Compsognathus from the Jura of Solenhofen. Huxley classes
-the latter with the Dinosauria, and believes them to be the nearest
-relations to the Tocornithes.
-
-The great majority of Birds--in spite of all the variety in the
-colouring of their beautiful feathery dress, and in the formation of
-their beaks and feet--are of an exceedingly uniform organization, in
-much the same way as are the class of insects. The bird form has adapted
-itself on all sides to the external conditions of existence, without
-having thereby in any way essentially deviated from the strict
-hereditary type of its characteristic structure. There are only two
-small groups, the feather-tailed birds (Saururæ) and those of the
-ostrich kind, which differ considerably from the usual type of bird,
-namely, from those with keel-shaped breasts (Carinatæ), and hence the
-whole class may be divided into three sub-classes.
-
-The first sub-class, the _Reptile-tailed_, or _Feather-tailed Birds_
-(Saururæ), are as yet known only through a single, and that an
-imperfect, fossil impression, which, however, in being the oldest and
-also a very peculiar fossil bird, is of great importance. This fossil is
-the Primæval Griffin, or Archæopteryx lithographica, of which as yet
-only one specimen has been found in the lithographic slate at
-Solenhofen, in the Upper Jura system of Bavaria. This remarkable bird
-seems on the whole to have been of the size and form of a large raven,
-especially as regards the legs, which are in a good state of
-preservation; head and breast unfortunately are wanting. The formation
-of the wings deviates somewhat from that of other birds, but that of the
-tail still more so. In all other birds the tail is very short and
-composed of but few short vertebræ; the last of these have grown
-together into a thin, bony plate standing perpendicularly, upon which
-the rudder-feathers of the tail are attached in the form of a fan. The
-Archæopteryx, however, has a long tail like a lizard, composed of
-numerous (20) long thin vertebræ, and on every vertebra are attached
-the strong rudder-feathers in twos, so that the whole tail appears
-regularly feathered. This same formation of the tail part of the
-vertebral column occurs transiently in the embryos of other birds, so
-that the tail of the Archæopteryx evidently represents the original form
-of bird-tail inherited from reptiles. Large numbers of similar birds
-with lizard-tails probably lived during the middle of the secondary
-period; accident has as yet, however, only revealed this one fossil.
-
-The _Fan-tailed_, or _Keel-breasted birds_ (Carinatæ), which form the
-second sub-class, comprise all living Birds of the present day, with the
-exception of those of the ostrich kind, or Ratitæ. They probably
-developed out of Feather-tailed Birds during the first half of the
-secondary period, namely, in the Jura or Chalk period, by the hinder
-tail vertebræ growing together, and by the tail becoming shortened. Only
-very few remains of them are known from the secondary period, and these
-moreover only out of the last section of it, namely, from the Chalk.
-These remains belong to a swimming bird of the albatross species, and a
-wading bird like a snipe. All the other fossil remains of birds as yet
-known have been found in the tertiary strata.
-
-The _Bushy-tailed_, or _Ostrich-like Birds_ (Ratitæ), also called
-_Running Birds_ (Cursores), the third and last sub-class, is now
-represented only by a few living species, by the African ostrich with
-two toes, the American and Australian ostrich with three toes, by the
-Indian cassowary and the four-toed kiwi, or Apteryx, in New Zealand. The
-extinct giant birds of Madagascar (Æpyornis) and the New Zealand
-Dinornis, which were much larger than the still living ostriches, also
-belong to this group. The Birds of the ostrich kind--by giving up the
-habit of flying, by the degeneration of the muscles for flying resulting
-from this, and of the breast bone which serves as their support, and by
-the corresponding stronger development of the hinder legs for
-running--have probably arisen out of a branch of the Keel-breasted
-birds. But possibly, as Huxley thinks, they may be the nearest relations
-of the Dinosauria and of the Reptiles akin to them, especially of the
-Compsognathus; at all events, the common primary form of all Birds must
-be looked for among the extinct Reptiles.
-
-
-
-
-CHAPTER XXI.
-
-PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-IV. MAMMALS.
-
-
-  The System of Mammals according to Linnæus and
-  Blainville.--Three Sub-classes of Mammals (Ornithodelphia,
-  Didelphia, Monodelphia).--Ornithodelphia, or Monotrema.--Beaked
-  Animals (Ornithostoma).--Didelphia, or Marsupials.--Herbivorous
-  and Carnivorous Marsupials.--Monodelphia, or Placentalia
-  (Placental Animals).--Meaning of the Placenta.--Tuft
-  Placentalia.--Girdle Placentalia.--Disc
-  Placentalia.--Non-deciduates, or Indeciduata.--Hoofed
-  Animals.--Single and Double-hoofed Animals.--Whales.--Toothless
-  Animals.--Deciduates, or Animals with
-  Decidua.--Semi-apes.--Gnawing Animals.--Pseudo-hoofed
-  Animals.--Insectivora.--Beasts of Prey.--Bats.--Apes.
-
-
-There are only a few points in the classification of organisms upon
-which naturalists have always agreed. One of these few undisputed points
-is the privileged position of the class of Mammals at the head of the
-animal kingdom. The reason of this privilege consists partly in the
-special interest, also in the various uses and the many pleasures, which
-Mammals, more than all other animals, offer to man, and partly in the
-circumstance that man himself is a member of this class. For however
-differently in other respects man's position in nature and in the system
-of animals may have been regarded, yet no naturalist has ever doubted
-that man, at least from a purely morphological point of view, belongs
-to the class of Mammals. From this there directly follows the
-exceedingly important inference that man, by consanguinity also, is a
-member of this class of animals, and has historically developed out of
-long since extinct forms of Mammals. This circumstance alone justifies
-us here in turning our especial attention to the history and the
-pedigree of Mammals. Let us, therefore, for this purpose first examine
-the groups of this class of animals.
-
-Older naturalists, especially considering the formation of the jaw and
-feet, divided the class of Mammals into a series of from eight to
-sixteen orders. The lowest stage of the series was occupied by the
-whales, which seemed to differ most from man, who stands at the highest
-stage, by their fish-like form of body. Thus Linnæus distinguished the
-following eight orders: (1) Cetæ (whales); (2) Belluæ (hippopotami and
-horses); (3) Pecora (ruminating animals); (4) Glires (gnawing animals
-and rhinoceroses); (5) Bestiæ (insectivora, marsupials, and various
-others); (6) Feræ (beasts of prey); (7) Bruta (toothless animals and
-elephants); (8) Primates (bats, semi-apes, apes, and men). Cuvier's
-classification, which became the standard of most subsequent zoologists,
-did not rise much above that of Linnæus. Cuvier distinguished the
-following eight orders: (1) Cetacea (whales); (2) Ruminantia (ruminating
-animals); (3) Pachyderma (hoofed animals, with the exclusion of
-ruminating animals); (4) Edentata (animals poor in teeth); (5) Rodentia
-(gnawing animals); (6) Carnassia (marsupials, beasts of prey,
-insectivora, and bats); (7) Quadrumana (semi-apes and apes); (8) Bimana
-(man).
-
-The most important advance in the classification of Mammals was made as
-early as 1816 by the eminent anatomist Blainville, who has already been
-mentioned, and who first clearly recognised the three natural main
-groups or sub-classes of Mammals, and distinguished them according to
-the formation of their generative organs as _Ornithodelphia_,
-_Didelphia_, and _Monodelphia_. As this division is now justly
-considered by all scientific zoologists to be the best, on account of
-solid foundation on the history of development, let us here keep to it
-also.
-
-The first sub-class consists of the _Cloacal Animals_, or _Breastless
-animals_, also called _Forked animals_ (Monotrema, or Ornithodelphia).
-This class is now represented only by two species of living mammals,
-both of which are confined to Australia and the neighbouring island of
-Van Diemen's land, namely, the well-known Water Duck-bill
-(Ornithorhynchus paradoxus) with the beak of a bird, and the less known
-Beaked Mole (Echidna hystrix), resembling a hedgehog. Both of these
-curious animals, which are classed in the order of _Beaked Animals_
-(Ornithostoma), are evidently the last surviving remnants of an animal
-group formerly rich in forms, which alone represented the Mammalia in
-the secondary epoch, and out of which the second sub-class, the
-Didelphia, developed later, probably in the Jurassic period.
-Unfortunately, we as yet do not know with certainty of any fossil
-remains of this most ancient primary group of Mammals, which we will
-call _Primary Mammals_ (Promammalia). Yet they possibly comprise the
-oldest of all the fossil Mammalia known, namely, the Microlestes
-antiquus, of which animals, however, we as yet only know some few small
-molar teeth. These have been found in the uppermost strata of the
-Trias, in the Keuper, first in Germany (at Degerloch, near Stuttgart,
-in 1847), later also in England (at Frome), in 1858. Similar teeth have
-lately been found also in the North American Trias, and have been
-described as Dromatherium sylvestre. These remarkable teeth, from the
-characteristic form of which we can conclude that they belonged to an
-insectivorous mammal, are the only remains of mammals as yet found in
-the older secondary strata, namely, in the Trias. It is possible,
-however, that besides these many of the other mammalian teeth found in
-the Jura and Chalk systems, which are still generally ascribed to
-Marsupials, in reality belong to Cloacal Animals. This cannot be decided
-with certainty owing to the absence of the characteristic soft parts. In
-any case, numerous Monotrema, with well-developed teeth and cloaca, must
-have preceded the advent of Marsupial animals.
-
-The designation, "_Cloacal animals_" (Monotrema), has been given to the
-Ornithodelphia on account of the cloaca which distinguishes them from
-all other Mammals; but which on the other hand makes them agree with
-Birds, Reptiles, and Amphibia, in fact, with the lower Vertebrata. The
-formation of the cloaca consists in the last portion of the intestinal
-canal receiving the mouth of the urogenital apparatus, that is, the
-united urinary and genital organs, whereas in all other Mammals
-(Didelphia as well Monodelphia) these organs have an opening distinct
-from that of the rectum. However, in these latter also the cloaca
-formation exists during the first period of their embryonal life, and
-the separation of the two openings takes place only at a later date (in
-man about the twelfth week of development). The Cloacal animals have
-also been called "_Forked animals_," because the collar-bones, by means
-of the breast bone, have become united into one piece, similar to the
-well-known fork-bone, or merry-thought, in birds. In all other Mammals
-the two collar-bones remain separated in front and do not fuse with the
-breast bone. Moreover, the coracoid bones are much more strongly
-developed in the Cloacal animals than in the other Mammalia, and are
-connected with the breast bone.
-
-In many other characteristics also--especially in the formation of their
-internal genital organs, their auricular labyrinth, and their
-brain--Beaked animals are more closely allied to the other Vertebrata
-than to Mammals, so that some naturalists have been inclined to separate
-them from the latter as a special class. However, like all other
-Mammals, they bring forth living young ones, which for a time are
-nourished with milk from the mother. But whereas in all other Mammals
-the milk issues through nipples, or teats, from the mammary glands,
-teats are completely wanting in beaked animals, and the milk comes
-simply out of a flat, sieve-like, perforated patch of the skin. Hence
-they may also be called _Breastless_ or _Teatless animals_ (Amasta).
-
-The curious formation of the beak in the two still living Beaked
-animals, which is connected with the suppression of the teeth, must
-evidently not be looked upon as an essential feature of the whole
-sub-class of Cloacal animals, but as an accidental character of
-adaptation distinguishing the last remnant of the class as much from the
-extinct main group, as the formation of a similar toothless snout
-distinguishes many toothless animals (for instance, the ant-eater) from
-the other placental animals. The unknown, extinct Primary Mammals, or
-Promammalia--which lived during the Trias period, and of which the two
-still living orders of Beaked animals represent but a single
-degenerated branch developed on one side--probably possessed a very
-highly developed jaw like the marsupial animals, which developed from
-them.
-
-_Marsupial_, or _Pouched Animals_ (Didelphia, or Marsupialia), the
-second of the three sub-classes of Mammals, form in every respect--both
-as regards their anatomy and embryology, as well as their genealogy and
-history--the transition between the other sub-classes--the Cloacal and
-Placental Animals. Numerous representatives of this group still exist,
-especially the well-known kangaroos, pouched rats, and pouched dogs; but
-on the whole this sub-class, like the preceding one, is evidently
-approaching its complete extinction, and the living members of the class
-are the last surviving remnants of a large group rich in forms, which
-represented the Mammalia during the more recent secondary and the
-earlier tertiary periods. The Marsupial Animals probably developed
-towards the middle of the Mesolithic epoch (during the Jura) out of a
-branch of the Cloacal Animals, and in the beginning of the Tertiary
-epoch again, the group of Placental Animals arose out of the Marsupials,
-and the latter then succumbed to the former in the struggle for life.
-All the fossil remains of Mammals known to us from the Secondary epoch,
-belong either exclusively to Marsupials, or partly perhaps to Cloacal
-animals. At that time Marsupials seem to have been distributed over the
-whole earth; even in Europe (France and England), well-preserved fossil
-remains of them have been found. On the other hand, the last off-shoots
-of the sub-class now living are confined to a very narrow tract of
-distribution, namely, to Australia, the Australasian, and a small part
-of the Asiatic Archipelago. There are also a few species still living
-in America, but at the present day not a single marsupial animal lives
-on the continent of Asia, Africa, or Europe.
-
-The name of pouched animals is given to the class on account of the
-purse-shaped pouch (marsupium) existing in most instances on the
-abdominal side of the female animals, in which the mother carries about
-her young for a considerable time after their birth. This pouch is
-supported by two characteristic marsupial bones, also existing in
-Cloacal animals, but not in Placental animals. The young Marsupial
-animal is born in a much more imperfect form than the young Placental
-animal, and only attains the same degree of development which the latter
-possesses directly at its birth, after it has developed in the pouch for
-some time. In the case of the giant kangaroo, which attains the height
-of a man, the newly born young one, which has been carried in the
-maternal womb not much longer than five weeks, is not more than an inch
-in length, and only attains its essential development subsequently, in
-the pouch of the mother, where it remains about nine months attached to
-the nipple of the mammary gland.
-
-The different divisions generally distinguished as families in the
-sub-class of Marsupial animals, deserve in reality the rank of
-independent orders, for they differ from one another in manifold
-differentiations of the jaw and limbs, in much the same manner, although
-not so sharply, as the various orders of Placental animals. In part they
-perfectly agree with the latter. It is evident that adaptation to
-similar conditions of life has effected entirely coincident or analogous
-transformations of the original fundamental form in the two sub-classes
-of Marsupials. According to this, about eight orders of Marsupial
-animals may be distinguished, the one half of the main group or legion
-of which are herbivorous, the other half carnivorous. The oldest fossil
-remains of the two legions (if the previously mentioned Microlestes and
-the Dromatherium are not included) occur in the Jurassic strata, namely,
-in the slates of Stonesfield, near Oxford. The slates belong to the
-Bath, or the Lower Oolite formation--strata which lie directly above the
-Lias, the oldest Jura formation. (Compare p. 15.) It is true that the
-remains of Marsupials found in the slates of Stonesfield, as well as
-those which were found later in the Purbeck strata, consist only of
-lower jaws. (Compare p. 29.) But fortunately the lower jaw is just one
-of the most characteristic parts of the skeleton of Marsupials. For it
-is distinguished by a hook-shaped process of the lower corner of the jaw
-turning downwards and backwards, which neither occurs in Placental nor
-in the (still living) Cloacal animals, and from the existence of this
-process on the lower jaws from Stonesfield, we may infer that they
-belonged to Marsupials.
-
-
-SYSTEMATIC SURVEY OF CLOACAL AND MARSUPIAL MAMMALIA.
-
-I. _First Sub-class of Mammalia:_
-
-_Forked or Cloacal Animals (Monotrema, or Ornithodelphia)._
-
-Mammals with Cloaca, without Placenta, with Marsupial Bones.
-
-  ------------------------------------------------------------------------------------
-         I.         }
-  =Primary Mammals= } Unknown extinct Mammalia from the           { (Microlestes?)
-    +Promammalia+   }         Trias Period                        { (Dromatherium?)
-
-         II.        } 1. Aquatic beaked       1. Ornithorhynchida { 1. Ornithorhynchus
-  =Beaked Animals=  }      animals                                {    paradoxus
-  +Ornithostoma+    }   2. Terrestrial        2. Echidnida        { 2. Echidna hystrix
-                    }   beaked animals                            {
-  ------------------------------------------------------------------------------------
-  II. _Second Sub-class of Mammalia:_
-
-  _Pouched or Marsupial Animals (Marsupialia, or Didelphia)._
-
-  Mammals without Cloaca, without Placenta, with Marsupial Bones.
-  ------------------------------------------------------------------------------------
-  _Legions_       |      _Orders_       |    _Systematic Name_  | _Families of the_
-  _of_            |        _of_         |         _of_          |  _Marsupialia._
-  _Marsupialia._  |    _Marsupialia._   |     _the Orders._     |
-  ------------------------------------------------------------------------------------
-                  {   1. Hoofed             1. Barypoda         { 1. Stereognathida
-                  { Marsupial animals                           { 2. Nototherida
-       III.       {                                             { 3. Diprotodontia
-   =Herbivorous=  {
-    =Marsupial=   {  2. Kangaroo            2. Macropoda        { 4. Plagiaulacida
-     =Animals=    { Marsupial animals                           { 5. Halmaturida
-                  { (Leaping pouched                            { 6. Dendrolagida
-   +Marsupialia+  {    animals)
-   +Botanophaga+  {
-                  {  3. Root-eating         3. Rhizophaga       {
-                  { Marsupial animals                           {
-                  { (Gnawing pouched                            { 7. Phascolomyida
-                  {    animals)                                 {
-                  {
-                  {  4. Fruit eating        4. Carpophaga       {
-                  { Marsupial animals                           { 8. Phascolarctida
-                  { (Climbing pouched                           { 9. Phalangistida
-                  {     animals)                                { 10. Petaurida
-
-                  { 5. Insectivorous        5. Cantharophaga    { 11. Thylacotherida
-                  {  Marsupial animals                          { 12. Spalacotherida
-                  { (Primæval pouched                           { 13. Myrmecobida
-                  {     animals)                                { 14. Peramelida
-       IV.        {
-   =Carnivorous=  { 6. Marsupial animals    6. Edentula         {
-    =Marsupial=   {     poor in teeth                           {
-     =Animals=    {    (Pouched animals                         { 15. Tarsipedina
-                  {      with trunks)                           {
-                  {
-                  { 7. Rapacious marsupial  7. Creophaga        { 16. Dasyurida
-                  {      animals                                { 17. Thylacinida
-   +Marsupialia+  {  (Rapacious pouched                         { 18. Thylacoleonida
-    +Zoophaga+    {      animals)
-                  {
-                  {  8. Ape-footed          8. Pedimana         {
-                  { Marsupial animals                           { 19. Chironectida
-                  { (Pouched animals                            { 20. Didelphyida
-                  {    with hands)
-
-
-SYSTEMATIC SURVEY OF PLACENTAL ANIMALS.
-
-III. _Third Sub-class of Mammalia:_
-
-_Placentalia, or Monodelphia (Placental Animals)._
-
-Mammals without Cloaca, with Placenta, without Marsupial Bones.
-
-
- -----------------------------------------------------------------------------------
-     _Legions of_     |    _Orders of_     |  _Sub-orders of_    |_Systematic Name_
-        _the_         |       _the_        |       _the_         |      _of_
-  _Placental Animals._|_Placental Animals._|_Placental Animals._ | _the Sub-orders._
- -----------------------------------------------------------------------------------
-  III. 1. INDECIDUA. _Placental Animals without Decidua._
- -----------------------------------------------------------------------------------
-          V.          { I. Single-hoofed   { 1. Tapirs              1. Tapiromorpha
-     =Hoofed Animals= {  _Perissodactyla_  { 2. Horses              2. Solidungula
-      +Ungulata+      {
-                      { II. Double-hoofed  { 3. Pigs                3. Choeromorpha
-                      {   _Artiodactyla_   { 4. Ruminating          4. Ruminantia
-
-                      { III. Herbivorous   {
-          VI.         {      Whales        { 5. Sea cows            5. Sirenia
-        =Whales=      {    _Phycoceta_     {
-       +Cetacea+      {
-                      { IV. Carnivorous    { 6. Whales              6. Autoceta
-                      {     Whales         { 7. Zeuglodonta         7. Zeugloceta
-                      {  _Sarcoceta_       {
-
-         VII.         { V. Digging Animals { 8. Ant-eaters          8. Vermilinguia
-       =Animals=      {   _Effodientia_    { 9. Armadilloes         9. Cingulata
-     =poor in teeth=  {
-       +Edentata+     {   VI. Sloths       { 10. Giant Sloths      10. Gravigrada
-                      {   _Bradypoda_      { 11. Dwarf Sloths      11. Tardigrada
- -----------------------------------------------------------------------------------
-  III. 2. DECIDUATA. _Placental Animals with Decidua._
- -----------------------------------------------------------------------------------
-        VIII.         {  VII. Rapacious    {12. Rapacious land     12. Carnivora
-  =Placental Animals= {      Animals       {      animals
-  +Zonoplacentalia+   {     _Carnaria_     {13. Rapacious sea      13. Pinnipedia
-                      {                    {      animals
-                      {
-                      { VIII. False-hoofed {14. Hyrax              14. Lamnungia
-                      {      Animals       {15. Toxodonts          15. Toxodontia
-                      {    _Chelophora_    {16. Dinotheria         16. Gonyognatha
-                      {                    {17. Elephants          17. Proboscidea
-
-
-          XI.         {  IX. Semi-apes     {18. Fingered animals   18. Leptodactyla
-    =Disc Placental=  {   _Prosimiæ_       {19. Flying lemur       19. Ptenopleura
-       =Animals=      {                    {20. Long-footed        20. Macrotarsi
-  +Discoplacentalia+  {                    {21. Short-footed       21. Brachytarsi
-                      {
-                      { X. Gnawing Animals {22. Squirrel species   22. Sciuromorpha
-                      {     _Rodentia_     {23. Mouse species      23. Myomorpha
-                      {                    {24. Porcupine species  24. Hystrichomorpha
-                      {                    {25. Hare species       25. Lagomorpha
-                      {
-                      { XI. Insect-eating  {26. With a coecum      26. Menotyphla
-                      {     Animals        {27. Without a          27. Lipotyphla
-                      {   _Insectivora_    {      coecum
-                      {
-                      { XII. Flying Animals{28. Flying foxes       28. Pterocynes
-                      {    _Chiroptera_    {29. Bats               29. Nycterides
-                      {
-                      {    XIII. Apes      { 30. Clawed apes       30. Arctopitheci
-                      {     _Simiæ_        { 31. Flat-nosed        31. Platyrrhinæ
-                      {                    { 32. Narrow-nosed      32. Catarrhinæ
-
-             ----------------------------------------------------------------
-
-                                          =Man=
-                                        +Homines+
-                  Elephants                |
-                 _Proboscidea_             |           Bats
-                       |                   |        _Nycterides_
-    Rock Conies        |                   |             |      Marine animals of prey
-     _Lamnungia_       |             Narrow-nosed        |           _Pinnipedia_
-          |            |              _Catarrhinæ_       |                 |
-          |            |                   |        Flying foxes           |
-          \------v-----/     Flat-nosed    |         _Pterocynes_          |
-          Pseudo-hoofed      _Platyrrhinæ_ |       =Flying Animals=        |
-            _Chelophora_          |        |         +Chiroptera+          |
-                  |               |        |             |                 |
-                  |               \----v---/             |       Land animals of prey
-                  |                  =Apes=              |            _Carnivora_
-           =Gnawing Animals=         +Simiæ+             |         =Animals of Prey=
-              +Rodentia+               |                 |            +Carnaria+
-                  |  Fingered animals  |     Lemurs      |                 |
-                  |    _Leptodactyla_  |   _Brachytarsi_ |                 |
-      True        |          |         |        |        \-------v---------/
-     whales       |          |         |        |          Insect eaters
-    _Sarcoceta_   \-----v----/         \---v----/           _Insectivora_
-        |               |                  |                     |
-        |               \------------------v---------------------/
-     Sea cows                           Semi-apes
-     _Sirenia_                          _Prosimiæ_
-     =Whales=                        =Deciduous Animals=
-     +Cetacea+                           +Deciduata+
-        |          Poor in teeth            |
-  =Hoofed Animals=  _Edentata_              |
-     +Ungulata+          |                  |
-        |                |                  |
-        \-------v--------/                  |
-           =Indeciduous=                    |
-           +Indeciduata+                    |
-                |                           |
-                \-------------v-------------/
-                     =Placental Animals=
-                         +Placentalia+
-    Herbivorous marsupials    |     Carnivorous marsupials
-    _Marsupialia botanophaga_ |      _Marsupialia zoophaga_
-               |              |                 |
-               \--------------v-----------------/
-                         =Marsupial=
-                        +Marsupialia+
-    Beaked animals            |
-     _Ornithostoma_           |
-           |                  |
-           \---------v--------/
-             Primary mammals
-               _Promammalia_
-             =Cloacal Animals=
-                +Monotrema+
-
-
-Of _Herbivorous marsupials_ (Botanophaga), only two fossils are as yet
-known from the Jura, namely, the Stereognathus ooliticus, from the
-slates of Stonesfield (Lower Oolite), and the Plagiaulax Becklesii, from
-the middle Purbeck strata (Upper Oolite). But in Australia there are
-gigantic fossil remains of extinct herbivorous Marsupials from the
-diluvial period (Diprotodon and Nototherium) which were far larger than
-the largest of the still living Marsupials. The Diprotodon Australis,
-whose skull alone is three feet long, exceeded even the river-horse, or
-Hippopotamus, in size and upon the whole resembled it in the unwieldy
-and clumsy form of body. This extinct group, which probably corresponded
-with the gigantic placental hoofed animals of the present day--the
-hippopotami and rhinoceroses--may be called Hoofed Marsupials
-(Barypoda). Closely allied to them is the order of kangaroos, or Leaping
-Marsupials (Macropoda), which all have seen in zoological gardens. In
-their shortened fore legs, their very lengthened hind legs, and very
-strong tail, which serves as a jumping pole, they correspond with the
-leaping mice in the class of Rodents. Their jaw, however, resembles that
-of horses, and their complex stomach that of Ruminants. A third order of
-Herbivorous Marsupials corresponds in its jaws to Rodents, and in its
-subterranean mode of life, especially, to digging mice. Hence they may
-be termed Rodent Marsupials, or root-eating pouched animals
-(Rhizophaga). They are now represented only by the Australian wombat
-(Phascolomys). A fourth and last order of Herbivorous Marsupials is
-formed by the climbing or Fruit-eating Marsupials (Carpophaga), whose
-mode of life and structure resembles partly that of squirrels, partly
-that of apes (Phalangista, Phascolarctus).
-
-The second legion of Marsupials, the _Carnivorous Marsupials_
-(Zoophaga), is likewise divided into four main groups or orders. The
-most ancient of these is that of the primæval, or Insectivorous
-Marsupials (Cantharophaga). It probably includes the primary forms of
-the whole legion, and possibly also those of the whole sub-class. At
-least, all the lower jaws from Stonesfield (with the exception of the
-Stereognathus) belong to Insectivorous Marsupials, and the still living
-Myrmecobius is their nearest relative. But some of those oolitic
-Primæval Marsupials possessed a larger number of teeth than all the
-other known mammals, for each half of the lower jaw of the
-Thylacotherium contained sixteen teeth (three incisors, one canine
-tooth, six pseudo, and six genuine molars). If the upper jaw, which is
-unknown, had as many teeth, then the Thylacotherium had no less than
-sixty-four teeth, just double the number possessed by man. The Primæval
-Marsupials correspond, on the whole, with the Insectivora among
-Placental animals, which order includes hedgehogs, moles, and
-shrew-mice. A second order, which has probably developed out of a branch
-of the last, consists of the Snouted, or Toothless Marsupials
-(Edentula), which resemble the Toothless animals, or Edentata, among the
-Placental animals by their tube-shaped snout, their degenerated jaws,
-and their corresponding mode of life. On the other hand, the mode of
-life and formation of the jaws of Rapacious marsupials (Creophaga)
-correspond with those of the genuine Beasts of Prey, or Carnivora, among
-Placental animals. This order includes the pouched marten (Dasyurus) and
-the pouched wolf (Thylacinus) in Australia. Although the latter attains
-to the size of a wolf, it is but a dwarf in comparison with the extinct
-Australian pouched lions (Thylacoleo) which were at least as large as a
-lion, and possessed huge canine teeth more than two inches in length.
-Finally, the eighth and last order is formed by the marsupials with
-hands, or the Ape-footed Pouched animals (Pedimana), which live both in
-Australia and America. They are frequently kept in zoological gardens,
-especially the different species of the genus Didelphys, and are known
-by the name of pouched rats, bush rats, or opossums. The thumb on their
-hinder feet is opposable to the four other toes, as in a hand, and by
-this they are directly allied to the Semi-apes, or Prosimia, among
-Placental animals. It is possible that these latter are really next akin
-to the marsupials with hands, and that they have developed out of their
-long since extinct ancestors.
-
-It is very difficult to discover the genealogy of Marsupials, and this
-more especially because we are but very imperfectly acquainted with the
-whole sub-class; and the Marsupials of the present day are evidently
-only the last remnants of a group that was at one time rich in forms. It
-is possible that Marsupials with hands, those with snouts, as well as
-rapacious Marsupials, developed as three diverging branches out of the
-common primary group of Primæval Marsupials. In a similar manner, on the
-other hand, the rodent, leaping, and hoofed Marsupials have perhaps
-arisen as three diverging branches out of the common herbivorous primary
-group, that is, out of the Climbing Marsupials. Climbing and Primæval
-Marsupials might, however, be two diverging branches of the common
-primary forms of all Marsupials, that is, of the _Primary Marsupials_
-(Prodidelphia), which originated during the older secondary period out
-of Cloacal animals.
-
-The third and last sub-class of mammals comprises the _Placental
-animals_, or _Placentals_ (Monodelphia, or Placentalia). It is by far
-the most important, comprehensive, and most perfect of the three
-sub-classes; for the class includes all the known mammalia, with the
-exception of Marsupials and Beaked animals. Man also belongs to this
-sub-class, and has developed out of its lower members.
-
-Placental animals, as their name indicates, are distinguished from all
-other mammals, more especially by the formation of a so called
-_placenta_. This is a very peculiar and remarkable organ, which plays
-an exceedingly important part in nourishing the young one developing in
-the maternal body. The placenta (also called after-birth) is a soft,
-spongy, red body, which differs very much in form and size, but which
-consists for the most part of an intricate network of veins and blood
-vessels. Its importance lies in the exchange of substance between the
-nutritive blood of the maternal womb, or uterus, and the body of the
-germ, or embryo. (See vol. i. p. 298.) This very important organ is
-developed neither in marsupials nor in beaked animals. But placental
-animals are also distinguished from these two sub-classes by many other
-peculiarities, thus more especially by the absence of marsupial bones,
-by the higher development of the internal sexual organs, and by the more
-perfect development of the brain, especially of the so-called callous
-body or beam (_corpus callosum_), which, as the intermediate commissure,
-or transverse bridge, connects the two hemispheres of the large brain
-with each other. Placental animals also do not possess the peculiar
-hooked process of the lower jaw which characterizes Marsupials. The
-following classification (p. 246) of the most important characteristics
-of the three sub-classes will best explain how Marsupials, in these
-anatomical respects, stand midway between Cloacal and Placental animals.
-
-Placental animals are more variously differentiated and perfected, and
-this, moreover, in a far higher degree, than Marsupials, and they have,
-on this account, long since been arranged into a number of orders,
-differing principally in the formation of the jaws and feet. But what is
-even of more importance than these, is the different development of the
-placenta, and the manner of its connection with the maternal uterus.
-For in the three lower orders of Placental animals, in Hoofed animals,
-Whales, and Toothless animals, the peculiar spongy membrane, which is
-called the _deciduous membrane_, or _decidua_, and which connects the
-maternal and the foetal portions of the placenta, does _not_ become
-developed. This takes place exclusively in the seven higher orders of
-Placental animals, and we may, therefore, according to Huxley, class
-them in the main group of _Deciduata_, or animals with _decidua_. They
-are contrasted with the three first-mentioned legions of indeciduous
-animals, or _Indeciduata_.
-
-
-  ---------------------------+-------------------+-------------------+-------------------
-                             | _Cloacal Animals_ | _Pouched Animals_ |_Placental Animals_
-     _Three Sub-Classes_     |    MONOTREMA      |  MARSUPIALIA      |   PLACENTALIA
-             _of_            |      _or_         |      _or_         |       _or_
-          _Mammals._         |  ORNITHODELPHIA   |   DIDELPHIA       |   MONODELPHIA
-  ---------------------------+-------------------+-------------------+-------------------
-  1. Cloaca formation        |    Constant       |   Embryonal       |    Embryonal
-                             |                   |                   |
-  2. Nipples of the pectoral |    Wanting        |   Existing        |    Existing
-  glands, or milk            |                   |                   |
-  warts                      |                   |                   |
-                             |                   |                   |
-  3. Fore collar bones,      |    United         |   Not united      |    Not united
-  or clavicles, grown        |                   |                   |
-  together in the middle,    |                   |                   |
-  with the breast bone,      |                   |                   |
-  and forming a forked       |                   |                   |
-  bone                       |                   |                   |
-                             |                   |                   |
-  4. Marsupial bones         |    Existing       |    Existing       |     Wanting
-                             |                   |                   |
-  5. _Corpus callosum_ of    |     Feebly        |     Feebly        | Strongly developed
-  the brain                  |   developed       |   developed       |
-                             |                   |                   |
-  6. Placenta                |    Wanting        |    Wanting        |    Existing
-  ---------------------------+-------------------+-------------------+-------------------
-
-
-But in the various orders of Placental animals the placenta differs not
-only in important internal differences of structure, which are connected
-with the absence or the presence of a decidua, but also in the external
-form of the placenta itself. In the Indeciduata it consists, in most
-cases, of numerous, single, scattered bunches or tufts of vessels, and
-hence this group may be called _tufted placental animals_
-(Villiplacentalia). In the Deciduata, however, the single tufts of
-vessels are united into a cake, which appears in two different forms. In
-the one case it surrounds the embryo in the form of a closed band or
-ring, so that only the two poles of the oval egg bladder are free of
-tufts; this is the case in animals of prey (Carnaria) and the
-pseudo-hoofed animals (Chelophora), which may consequently be comprised
-as _girdled-placental animals_ (Zonoplacentalia). In the other
-Deciduata, to which man also belongs, the placenta is a simple round
-disc, and we therefore call them _disc-placentals_ (Discoplacentalia).
-This group includes the five orders of Semi-apes, Gnawing animals,
-Insectivora, Bats, and Apes, from the latter of which, in the zoological
-system, man cannot be separated.
-
-It may be considered as quite certain, from reasons based upon their
-comparative anatomy and their history of development, that Placental
-animals first developed out of Marsupials, and that this very important
-development--the first origin of the placenta--probably took place in
-the beginning of the tertiary epoch, during the eocene period. But one
-of the most difficult questions in the genealogy of animals is the
-important consideration whether all Placental animals have arisen out of
-one or out of several distinct branches of Marsupials; in other words,
-whether the origin of the placenta occurred but once, or several times.
-
-When, in my General Morphology, I for the first time endeavoured to
-establish the pedigree of Mammals, I here, as in most cases, preferred
-the monophyletic, or one-rooted, to the polyphyletic, or many-rooted,
-hypothesis of descent. I assumed that all Placental animals were derived
-from a single form of Marsupial animal, which, for the first time, began
-to form a placenta. In this case the Villiplacentals, Zonoplacentals,
-and Discoplacentals would perhaps have to be considered as three
-diverging branches of the common primary form of Placentals, or it might
-also be conceived that the two latter, the Deciduata, had developed only
-at a later period out of the Indeciduata, which on their part had arisen
-directly out of the Marsupials. However, there are also important
-reasons for the alternative; namely, that several groups of Placentals,
-differing from the beginning, arose out of several distinct groups of
-Marsupials, so that the placenta itself was formed several times
-independently. This opinion is maintained by Huxley, the most eminent
-English zoologist, and by many others. In this case the Indeciduata and
-the Deciduata would perhaps have to be considered as two completely
-distinct groups; then the order of Hoofed animals, as the primary group
-of the Indeciduata, might be supposed to have originated out of the
-Marsupial hoofed animals (Barypoda). Among the Deciduata, on the other
-hand, the order of Semi-apes, as the common primary form of the other
-orders, might possibly have arisen out of Handed Marsupials (Pedimana).
-But it is also conceivable that the Deciduata themselves have arisen out
-of several different orders of Marsupials, Animals of Prey out of
-Rapacious Marsupials, Gnawing animals out of Gnawing Marsupials,
-Semi-apes out of Handed Marsupials, etc. As we do not at present possess
-sufficient empiric material to solve this most difficult question, we
-must leave it and turn our attention to the history of the different
-orders of Placental animals, whose pedigree can often be very accurately
-established in detail.
-
-We must, as already remarked, consider the order of _Hoofed animals_
-(Ungulata) as the primary group of the Indeciduata, or Tuft-placentals;
-the two other orders, Whales and Toothless animals, developed out of
-them, as two diverging groups, probably only at a later period, by
-adaptation to very different modes of life. But it is also possible that
-the animals poor in teeth (Edentata) may be of quite a different origin.
-
-Hoofed animals are in many respects among the most important and the
-most interesting Mammals. They distinctly show that a true understanding
-of the natural relationship of animals can never be revealed to us
-merely by the study of living forms, but in all cases only by an equal
-consideration of their extinct and fossil blood-relations and ancestors.
-If, as is usually done, only the living Hoofed animals are taken into
-consideration, it seems quite natural to divide them into three entirely
-distinct orders, namely: (1) Horses, or _Single-hoofed animals_
-(Solidungula, or Equina); (2) Ruminating animals, or _Double-hoofed_
-(Bisulca, or Ruminantia); and (3) Thick-skinned, or _Many-hoofed_
-(Multungula, or Pachyderma). But as soon as the extinct Hoofed animals
-of the tertiary period are taken into consideration--of which animals we
-possess very numerous and important remains--it is seen that this
-division, but more especially the limitation of the Thick-skinned
-animals, is completely artificial, and that these three groups are
-merely top branches lopped from the pedigree of Hoofed animals, which
-are most closely connected by extinct intermediate forms. The one half
-of the Thick-skinned animals--rhinoceroses, tapirs, and
-palæotheria--manifest the closest relationships to horses, and have like
-them odd-toed feet; whereas the other half of the Thick-skinned
-animals--pigs, hippopotami, and anoplotheria--on account of their
-double-toed feet are much more closely allied to ruminating animals than
-to the former. Hence we must, in the first place, among Hoofed animals
-distinguish the two orders of Paired-hoofs and Odd-hoofs, as two natural
-groups, which developed as diverging branches out of the old tertiary
-primary group of Primary Hoofed animals, or Prochela.
-
-The order of _Odd-hoofed animals_ (Perissodactyla) comprises those
-Ungulata in which the middle (or third) toe of the foot is much more
-strongly developed than the others, so that it forms the actual centre
-of the hoof. This order includes the very ancient, common, primary group
-of all Hoofed animals, that is, the _Primary-hoofed animals_ (Prochela),
-which are found in a fossil state in the oldest Eocene strata
-(Lophiodon, Coryphodon, Pliolophus). Directly allied to this group is
-that branch which is the actual primary form of the Odd-hoofed animals,
-namely, the _Palæotheria_, fossils of which occur in the upper Eocene
-and lower Miocene. Out of the Palæotheria, at a later period, the
-rhinoceroses (Nasicornia) and rhinoceros-horses (Elasmotherida) on the
-one hand, and the tapirs, lama-tapirs, and primæval horses, on the
-other, developed as two diverging branches. The long since extinct
-primæval horses, or Anchitheria, formed the transition from the
-Palæotheria and tapirs to the Miocene horses, or hipparions, which are
-closely allied to the genuine living horses.
-
-The second main group of Hoofed animals, the order of _Pair-hoofed
-animals_ (Artiodactyla), comprises those hoofed animals in which the
-middle (third) and fourth toe of the foot are almost equally developed,
-so that the space between the two forms the central line of the entire
-foot. The order is divided into two sub-orders--the Pig-shaped and the
-Cud-chewing, or Ruminating. The _Pig-shaped_ (Choeromorpha) comprise in
-the first place the other branch of Primary-Hoofed-animals, the
-_Anoplotheria_, which we consider as the common primary form of all
-Pair-hoofed animals, or Artiodactyla (Dichobune, etc.). Out of the
-Anoplotheria arose, as two diverging branches, the primæval swine, or
-Anthracotheria, on the one hand, forming the transition to swine and
-river-horses, and the Xiphodonta on the other hand, forming the
-transition to Ruminating animals. The oldest _Ruminating animals_
-(Ruminantia) are the Primæval Stags, or Dremotheria, out of which,
-possibly, the stag-shaped (Elaphia), the hollow-horned (Cavicornia), and
-camels (Tylopoda), have developed as three diverging branches. Yet these
-latter are, in many respects, more allied to the Odd-hoofs than to the
-genuine Pair-hoofs. The accompanying systematic survey on p. 252, will
-show how the numerous families of Hoofed animals are grouped, in
-correspondence with this genealogical hypothesis.
-
-
-  SYSTEMATIC SURVEY
-
-  _Of the Sections and Families of Hoofed Animals, or Ungulata._
-
-  (N.B. Those families that are extinct are marked with an asterisk.)
-
-
-  ----------------+--------------------------------+------------------------+-------------------
-      _Orders_    |                                |                        |
-        _of_      |          _Sections_            |    _Families_          | _Systematic Name_
-      _Hoofed_    |             _of_               |       _of_             |        _of_
-     _animals._   |       _Hoofed Animals._        |  _Hoofed Animals._     |   _the Families._
-  ----------------+----------------------------=---+------------------------+-------------------
-        I.         {  I. Primary Hoofed              {  1. Lophiodonta        1. Lophiodontia*
-    =Odd-toed=     {       Animals.*                 {  2. Pliolophida        2. Pliolophida*
-     =Hoofed=      {      _Prochela_
-    =Animals=      {                                 {  3. Primary            3. Palæotherida*
-                   {                                 {    Odd-hoofs
-    +Ungulata+     {  II. Tapir-shaped               {  4. Lama-tapirs        4. Macrauchenida*
-                   {   _Tapiromorpha_                {  5. Tapirs             5. Tapirida
-  +Perissodactyla+ {                                 {  6. Rhinoceroses       6. Nasicornia
-                   {                                 {  7. Rhinoceros-horses  7. Elasmotherida*
-                   {
-                   {  III. Single-hoofs              {  8. Primæval           8. Anchitherida*
-                   {    _Solidungula_                {     horses
-                   {                                 {  9. Horses             9. Equina
-
-                   {                                 { 10. Primary           10. Anoplotherida*
-                   {                                 {    Pair-hoofs
-                   {                                 { 11. Primæval          11. Anthracotherida*
-                   {  IV. Pig-shaped                 {    pigs
-                   {  _Choeromorpha_                 { 12. Pigs              12. Setigera
-                   {                                 { 13. River horses      13. Obesa
-                   {                                 { 14. Primæval          14. Xiphodontia*
-                   {                                 {    ruminants
-                   {
-                   {              {                  {    {15. Primæval      15. Dremotherida*
-                   {              {                  {    {     deer
-        II.        {              { A. Stag-shaped   { a. {16. Pseudo        16. Tragulida
-    =Pair-toed=    {              {  _Elaphia_       {    {   musk deer
-     =Hoofed=      {              {                  {
-    =Animals=      {              {                  { b. {17. Musk deer     17. Moschida
-                   {              {                  {    {18. Deer          18. Cervina
-   +Ungulata+      {              {                  {
-                   {    V.        {                  { c. {19. Primæval      19. Sivatherida*
-  +Artiodactyla+   { Ruminating   {                  {    {  giraffes
-                   { animals      {                  {    {20. Giraffes      20. Devexa
-                   { _Ruminantia_ {
-                   {              {                  {    {21. Primæval      21. Antilocaprina*
-                   {              {                  { d. {  gazelles
-                   {              {                  {    {22. Gazelles      22. Antilopina
-                   {              {                  {
-                   {              { B. Hollow-horned {    {23. Goats         23. Caprina
-                   {              {  _Caricornia_    { e. {24. Sheep         24. Ovina
-                   {              {                  {    {25. Oxen          25. Bovina
-                   {              {
-                   {              { C. Pad-footed    { 26. Lamas             26. Auchenida
-                   {              {  _Tylopoda_      { 27. Camels            27. Camelida
-
-             ----------------------------------------------------------------
-
-    Oxen                       Giraffes
-      |                            |
-      |    Sheep         Deer      |
-      |      |             |       |
-      |      |             |       |
-      \--v---/  Goats      \---v---/  Musk deer              Horses
-         |        |            |          |                  _Equi_
-         |        |            |          |                     |
-         \---v-----/ Antelopes |          |   Camels            |
-             |           |     \----v-----/ and Lamas  Intermediate horses
-             |           |      Deer-shaped  _Tylopoda_    _Hippariones_
-             \-----v------/      _Elaphia_       |              |
-             Hollow-horned          |            |              |
-             _Cavicornia_           |            |              |
-                   |                |            |              |
-                   |                |            |       Primæval horses
-                   \-------v--------/            |       _Anchitherida_
-                     Primæval deer               |              |
-                     _Dremotherida_              |              |
-                           |                     |       =Single Hoofers=
-                           |                     |       +Solidungula+
-                           \--v------------------/              |
-                      =Ruminating Animals=                      |
-                         +Ruminantia+                           |
-  Sea-oxen                    |      Tapirs                     |
-  _Sirenia_                   |     _Tapirida_                  |
-     |     River-horses       |         |          Lama-tapirs  |
-     |       _Obesa_          |         |        _Macrauchenida_|
-     |          |             |         |                 |     |
-     |          |    Pigs     |         |                 |     |
-     \----v-----/ _Setigera_  |         \--------------v--/     |
-          |            |      |                        |        |
-          |            |      |      Rhinoceros-horses |        |
-          |            |      |       _Elasmotherida_  |        |
-          |            |      |              |         |        |
-         \------v-------/     |              |         |        |
-           Primæval pigs      | Rhinoceruses |         |        |
-         _Anthracotherida_    | _Nasicornia_ |         \---v-----/
-                |             |      |       |             |
-                | Primæval ruminants |       |             |
-                |   _Xiphodontia_    \---v---/             |
-                |             |          |                 |
-                |             |          |                 |
-                \------v------/          \--------v--------/
-               =Primary Pair-hoofs=         =Primary Odd-hoofs=
-                +Anoplotherida+             +Palæotherida+
-                       |                          |
-                       |                          |
-                       \------------v-------------/
-                                _Prochela_
-                         Primary-hoofed-animals
-                     (_Lophiodontia_ and _Pliophida_)
-                                    |
-                                    |
-                      (Hoofed marsupials? _Barypoda?_)
-
-
-It is probable that the remarkable legion of _Whales_ (Cetacea)
-originated out of Hoofed animals, which accustomed themselves
-exclusively to an aquatic life, and thereby became transformed into the
-shape of fish. Although these animals seem externally very like many
-genuine Fish, yet they are, as even Aristotle perceived, genuine
-Mammals. By their whole internal structure--in so far as it has not
-become changed by adaptation to an aquatic life--they, of all known
-Mammals, are most closely allied to Hoofed animals, and more especially
-agree with them in the absence of the decidua and in the tufted
-placenta. Even at the present day the river-horse (Hippopotamus)
-constitutes a kind of transition form to the Sea Cows (Sirenia), and
-from this it seems most probable that the extinct primary forms of the
-Cetacea are most closely allied to the Sea Cows of the present day, and
-that they developed out of Pair-hoofed animals, which were related to
-the hippopotamus. Out of the order of _Herbivorous whales_
-(Phycoceta)--to which the sea cows belong, and which accordingly, very
-probably, contain the primary forms of the legion--the other order of
-_Carnivorous whales_ (Sarcoceta) appears to have developed at a later
-period. But Huxley thinks that these latter were of quite a different
-origin, and that they arose out of the Carnaria through the Seals. Among
-the Sarcoceta, the extinct gigantic Zeuglodonta (Zeugloceta)--whose
-fossil skeletons some time ago excited great interest, it being thought
-that they were "sea serpents"--are probably only a peculiarly developed
-lateral branch of genuine whales (Autoceta), which comprise, besides the
-colossal whalebone whales, the cachalot or spermaceti whales, dolphins,
-narwhals, porpoises, etc.
-
-The third legion of the Indeciduata, or Sparsi-placentalia, comprises
-the strange group of the animals _poor in teeth_ (Edentata); it is
-composed of the two orders of burrowers and sloths. The order of
-_Burrowers_ (Effodientia) consists of the two sub-orders of _ant eaters_
-(Vermilinguia), to which the scaled animals also belong, and the _girdle
-animals_ (Cingulata), which were formerly represented by the gigantic
-Glyptodons. The order of _Sloths_ (Tardigrada) consists of the two
-sub-orders of the small, still living _dwarf sloths_ (Bradypoda), and
-of the extinct unwieldy _giant sloths_ (Gravigrada). The enormous fossil
-remains of these colossal herbivora suggest that the whole legion is
-becoming extinct, and that the Edentata of the present day are but a
-poor remnant of the mighty order of the diluvial period. The close
-relations between the still living South American Edentata and the
-extinct gigantic forms which are found beside the latter on the same
-part of the globe, made such an impression upon Darwin on his first
-visit to South America, that they even then suggested to him the
-fundamental idea of the Theory of Descent. (See above, vol. i. p. 134.)
-But it is precisely the genealogy of this legion which is most
-difficult. The Edentata are perhaps nothing but a peculiarly developed
-lateral branch of the Ungulata; but it may also be that their root lies
-in quite another direction.
-
-We now leave the first main group of Placental animals, the Indeciduata,
-and turn to the second main group, namely, the Deciduata, or animals
-with decidua, which are distinguished from the former by possessing a
-deciduous membrane, or decidua, during their embryonal life. We here
-meet with a very remarkable small group of animals, for the most part
-extinct, and which probably were the old tertiary (or eocene) ancestors
-of man. These are the Semi-apes, or Lemurs (Prosimiæ); these curious
-animals are probably the but little changed descendants of the primæval
-group of Placentalia which we have to consider as the common primary
-form of all Deciduata. They have hitherto been classed together in the
-same order with Apes which Blumenbach called Quadrumana (four-handed).
-However, I regard them as entirely distinct from these, not merely
-because they differ from all Apes, much more than do the most different
-Apes from one another, but also because they comprise most interesting
-transitional forms leading to the other orders of Deciduata. I conclude
-from this that the few still living Semi-apes, which moreover differ
-very much among one another, are the last surviving remnants of a
-primary group now almost extinct, but which was at one time rich in
-forms, and out of which all the other Deciduata (possibly with the
-single exception of Beasts of Prey, and Pseudo-hoofed animals) have
-developed as diverging branches. The old primary group of Semi-apes has
-probably developed out of Handed or Ape-footed Marsupials (Pedimana),
-which are surprisingly like them in the transformation of their hinder
-feet into grasping hands. The primæval primary forms themselves (which
-probably originated in the eocene period) are of course long since
-extinct, as are also the greater portion of the transition-forms between
-them and all the other orders of Deciduata. However, individual remnants
-of the latter are preserved among the Semi-apes of the present day.
-Among these, the remarkable Finger-animal of Madagascar (Chiromys
-madagascariensis) constitutes the remnant of the group of the
-Leptodactyla and the transition to Rodents. The strange flying lemur in
-the South Sea and Sunda islands (Galeopithecus), the only remnant of the
-group of Pteropleura, forms a perfect intermediate stage between
-Semi-apes and Bats. The long-footed Semi-apes (Tarsius, Otolicnus)
-constitute the last remnant of that primary branch (Macrotarsi) out of
-which the Insectivora developed. The short-footed forms (Brachytarsi)
-are the medium of connection between them and genuine Apes. The
-Short-footed Semi-apes comprise the long-tailed Lemur, the short-tailed
-Lichanotus, and the Stenops, the latter of which seems to be very
-closely allied to the probable ancestors of man among the Semi-apes. The
-short-footed as well as the long-footed Prosimiæ live widely distributed
-over the islands of southern Asia and Africa, more especially in
-Madagascar; some live also on the continent of Africa. No Semi-ape,
-either living or in a fossil state, has as yet been found in America.
-They all lead a solitary, nocturnal kind of life, and climb about on
-trees. (Compare vol. i. p. 361.)
-
-Among the six remaining orders of Deciduata, all of which are probably
-derived from long since extinct Semi-apes, the order of _Gnawing
-animals_ (Rodentia), which is rich in forms, has remained at the lowest
-stage. Among these the _squirrel-like_ animals (Sciuromorpha) stand
-nearest akin to the Pedimanous Marsupials. Out of this primary group the
-_mouse-like_ animals (Myomorpha) and the _porcupine-like_ animals
-(Hystricomorpha) developed probably as two diverging branches, the
-former of which are directly connected with the squirrel-like animals,
-by the eocene Myoxida, the latter by the eocene Psammoryctida. The
-fourth sub-order, the _hare-like_ animals (Lagomorpha), probably
-developed only at a later period out of one of the other three
-sub-orders.
-
-Very closely allied to the Rodentia is the remarkable order of
-_Pseudo-hoofed animals_ (Chelophora). Of these there now live but two
-genera, indigenous to Asia and Africa, namely, Elephants (Elephas), and
-Rock Conies (Hyrax). Both have hitherto generally been classed among
-real Hoofed animals, or Ungulata, with which they agree in the formation
-of the feet. But an identical transformation of nails or claws into
-hoofs occurs also in genuine Rodentia and in certain hoofed Rodentia
-(Subungulata) which live exclusively in South America. Beside smaller
-forms (for example, guinea pigs and gold hares) the Subungulata also
-include the largest of all Rodentia, namely, the Capybara Rats, which
-are about four feet in length. The Rock Conies, which are externally
-very nearly akin to Rodents, especially to the hoofed Rodents, were
-formerly classed among Rodentia by some celebrated zoologists, as an
-especial sub-class (Lamnungia). Elephants, on the other hand, when not
-classed among Hoofed animals, were generally considered as the
-representatives of a special order which were called Trunked animals
-(Proboscidea). But the formation of the placentas of Elephants and of
-Hyrax agree in a remarkable manner, and are entirely distinct from those
-of Hoofed animals. These latter never possess a decidua, whereas
-Elephants and Hyrax are genuine Deciduata. Their placenta is indeed not
-of the form of a disc, but of a girdle, as in the case of Animals of
-Prey; it is very possible that the girdle-shaped placenta is but a
-secondary development of the discoplacenta. Thus, then, it might be
-thought that the Pseudo-hoofed animals have developed out of a branch of
-the Rodentia, and in a similar manner perhaps the Carnivora out of a
-branch of the Insectivora. At all events, Elephants and Hyrax in many
-respects, especially in the formation of important skeletal parts, of
-the limbs, etc., are more closely allied to the Rodentia, and more
-especially to hoofed Rodentia, than to genuine Hoofed animals. Moreover
-several extinct forms, especially the remarkable South American
-Arrow-toothed animals (Toxodontia), stand in many respects midway
-between Elephants and Rodentia. That the still living Elephants and
-Hyrax are but the last survivors of a group of Pseudo-hoofed animals,
-which was once rich in forms, is proved not only by the very numerous
-fossil species of Elephants and Mastodon (some of which are even larger,
-others also much smaller than the Elephants of the present day), but
-also by the remarkable miocene _Dinotheria_ (Gonyognatha), between which
-and their next kindred, the Elephants, there must be a long series of
-unknown connecting intermediate forms. Taking all things into
-consideration, the most probable hypothesis which can be established at
-present as to the origin and the relationship of Elephants, Dinotheria,
-Toxodon, and Hyrax is, that they are the last survivors of a group of
-Pseudo-hoofed animals rich in forms, which developed out of the
-Rodentia, and probably out of relatives of the Subungulata.
-
-The order of _Insect Eaters_ (Insectivora) is a very ancient group, and
-is next akin to the common extinct primary form of the Deciduata, as
-well as to the Semi-apes of the present day. It has probably developed
-out of Semi-apes which were closely allied to the Long-footed Lemurs
-(Macrotarsi) of the present day. It is separated into two orders,
-Menotyphla and Lipotyphla; the Menotyphla are probably the older of the
-two, and are distinguished from the Lipotyphla by possessing an
-intestinal coecum, or typhlon. The Menotyphla include the climbing
-Tupajas of the Sunda Isles, and the leaping Macroscelides of Africa. The
-Lipotyphla are represented in our country by shrew mice, moles, and
-hedgehogs. The Insectivora, in the formation of their jaws and their
-mode of life, are nearly akin to Carnivora, but are, on the other hand,
-by their discoplacentas and by their large seminal vesicles, allied to
-Rodents.
-
-It is probable that the order of _Rapacious animals_ (Carnaria)
-developed out of a long since extinct branch of Insectivora, at the
-beginning of the Eocene period. It is a natural group, very rich in
-forms, but still of very uniform organization. The Rapacious animals are
-sometimes also called Girdle-placentals (Zonoplacentals), although the
-Pseudo-hoofed animals (Chelophora), in the same way, also deserve this
-designation. But as the latter, in other respects, are more closely
-allied to the Rodentia than to Carnaria, we have already discussed them
-in connection with the former. Animals of prey are divided into two,
-externally very different, but internally very closely related,
-sub-orders, namely, Land animals of prey and Marine animals of prey. The
-_Land animals of prey_ (Carnivora) comprise bears, dogs, cats, etc.,
-whose pedigree can be approximately guessed at by means of many extinct
-intermediate forms. The _Marine animals of prey_, or _Seals_
-(Pinnipedia), comprise sea bears, sea dogs, sea lions, and walruses.
-Although marine animals of prey appear externally very unlike land
-animals of prey, yet by their internal structure, their jaw and their
-peculiar girdle-shaped placenta, they are very nearly akin to them, and
-have evidently originated out of a branch of them, probably out of a
-kind of weasel (Mustelina). Even at the present day the fish otters
-(Lutra), and still more so the sea otters (Enhydris), present a direct
-form of transition to Seals, and clearly show how the bodies of land
-Carnivora are transformed into the shape of a Seal, by adaptation to an
-aquatic life, and how the steering fins of marine rapacious animals have
-arisen out of the legs of the former. The latter consequently stand in
-the same relation to the former as do the Whales to Hoofed animals
-among the Indeciduata. In the same way as the river-horse at present
-stands midway between the extreme branches of oxen and sea oxen, the sea
-otter still forms a surviving intermediate stage between the widely
-separated branches of dogs and sea dogs. In both cases the complete
-transformation of the external form, consequent upon adaptation to
-entirely different conditions of life, has not been able to efface the
-solid foundation of the inherited internal peculiarities.
-
-According to Huxley's opinion, which has already been quoted, only the
-Herbivorous Whales (Sirenia) are derived from Hoofed animals; on the
-other hand, the Carnivorous Cetacea (Sarcoceta) are derived from the
-marine animals of prey; the Zeuglodonts would form a transition between
-the two latter. But in this case it would be difficult to understand the
-close anatomical relations which exist between the Herbivorous and
-Carnivorous Cetacea. The strange peculiarities in the internal and
-external structure which so strikingly distinguish the two groups from
-all other mammals would then have to be regarded only as _analogies_
-(caused by the same kinds of adaptation), not as _homologies_
-(transmitted from a common primary form). The latter, however, strikes
-me as being by far the more probable, and hence I have left all the
-Cetacea among the Indeciduata as one group of kindred origin.
-
-The remarkable order of _Flying Mammals_, or _Bats_ (Chiroptera), stands
-near to the Carnaria as well as to the Insectivora. It has become
-strikingly transformed by adaptation to a flying mode of life, just as
-marine animals of prey have become modified by adaptation to a swimming
-mode of life. This order probably also originated out of the Semi-apes,
-with which it is even at present closely allied, through the flying
-lemurs (Galeopithecus). Of the two orders of flying animals, the
-insect-eating forms, or _flying mice_ (Nycterides), probably developed
-out of those eating fruits, or _flying foxes_ (Pterocynes); for the
-latter are, in many ways, more closely allied to Semi-apes than are the
-former.
-
-We have now still to discuss the genuine Apes (Simiæ) as the last order
-of Mammals; but as, according to the zoological system, the human race
-belongs to this order, and as it undoubtedly developed historically out
-of a branch of this order, we shall devote a special chapter to a more
-careful examination of its pedigree and history.
-
-
-
-
-CHAPTER XXII.
-
-ORIGIN AND PEDIGREE OF MAN.
-
-
-  The Application of the Theory of Descent to Man.--Its Immense
-  Importance and Logical Necessity.--Man's Position in the Natural
-  System of Animals, among Disco-placental Animals.--Incorrect
-  Separation of the Bimana and Quadrumana.--Correct Separation of
-  Semi-apes from Apes.--Man's Position in the Order of
-  Apes.--Narrow-nosed Apes (of the Old World) and Flat-nosed Apes
-  (of America).--Difference of the two Groups.--Origin of Man from
-  Narrow-nosed Apes.--Human Apes, or Anthropoides.--African Human
-  Apes (Gorilla and Chimpanzee).--Asiatic Human Apes (Orang and
-  Gibbon).--Comparison between the different Human Apes and the
-  different Races of Men.--Survey of the Series of the Progenitors
-  of Man.--Invertebrate Progenitors (Prochordata) and Vertebrate
-  Progenitors.
-
-
-Of all the individual questions answered by the Theory of Descent, of
-all the special inferences drawn from it, there is none of such
-importance as the application of this doctrine to Man himself. As I
-remarked at the beginning of this treatise, the inexorable necessity of
-the strictest logic forces us to draw the special deductive conclusion
-from the general inductive law of the theory, that Man has developed
-gradually, and step by step, out of the lower Vertebrata, and more
-immediately out of Ape-like Mammals. That this doctrine is an
-inseparable part of the Theory of Descent, and hence also of the
-universal Theory of Development in general, is recognized by all
-thoughtful adherents of the theory, as well as by all its opponents who
-reason logically.
-
-But if the doctrine be true, then the recognition of the animal origin
-and pedigree of the human race will necessarily affect more deeply than
-any other progress of the human mind the views we form of all human
-relations, and the aims of all human science. It must sooner or later
-produce a complete revolution in the conception entertained by man of
-the entire universe. I am firmly convinced that in future this immense
-advance in our knowledge will be regarded as the beginning of a new
-period of the development of Mankind. It can only be compared to the
-discovery made by Copernicus, who was the first who ventured distinctly
-to express the opinion, that it was not the sun which moved round the
-earth, but the earth round the sun. Just as the _geocentric conception_
-of the universe--namely, the false opinion that the earth was the centre
-of the universe, and that all its other portions revolved round the
-earth--was overthrown by the system of the universe established by
-Copernicus and his followers, so the _anthropocentric conception_ of the
-universe--the vain delusion that Man is the centre of terrestrial
-nature, and that its whole aim is merely to serve him--is overthrown by
-the application (attempted long since by Lamarck) of the theory of
-descent to Man. As Copernicus' system of the universe was mechanically
-established by Newton's theory of gravitation, we see Lamarck's theory
-of descent attain its causal establishment by Darwin's theory of
-selection. This comparison, which is very interesting in many respects,
-I have discussed in detail elsewhere.
-
-In order to carry out this extremely important application of the Theory
-of Descent to man, with the necessary impartiality and objectivity, I
-must above all beg the reader (at least for a short time) to lay aside
-all traditional and customary ideas on the "Creation of Man," and to
-divest himself of the deep-rooted prejudices concerning it, which are
-implanted in the mind in earliest youth. If he fail to do this, he
-cannot objectively estimate the weight of the scientific arguments which
-I shall bring forward in favour of the animal derivation of Man, that
-is, of his origin out of Ape-like Mammals. We cannot here do better than
-imagine ourselves with Huxley to be the inhabitants of another planet,
-who, taking the opportunity of a scientific journey through the
-universe, have arrived upon the earth and have there met with a peculiar
-two-legged mammal called Man, diffused over the whole earth in great
-numbers. In order to examine him zoologically, we should pack a number
-of the individuals of different ages and from different lands (as we
-should do with the other animals collected on the earth) into large
-vessels filled with spirits of wine, and on our return to our own planet
-we should commence the comparative anatomy of all these terrestrial
-animals quite objectively. As we should have no personal interest in
-Man, in a creature so entirely different from ourselves, we should
-examine and criticise him as impartially and objectively as we should
-the other terrestrial animals. In doing this we should, of course, in
-the first place refrain from all conjectures and speculations on the
-nature of his soul, or on the spiritual side of his nature, as it is
-usually called. We should occupy ourselves solely with his bodily
-structure, and with that natural conception of it which is offered by
-the history of his individual development.
-
-It is evident that in order correctly to determine Man's position among
-the other terrestrial organisms we must, in the first place, follow the
-guidance of the natural system. We must endeavour to determine the
-position which belongs to Man in the natural system of animals as
-accurately and distinctly as possible. We shall then, if in fact the
-theory of descent be correct, be able from his position in the system to
-determine the real primary relationship, and the degree of consanguinity
-connecting Man with the animals most like him. The hypothetical pedigree
-of the human race will then follow naturally as the final result of this
-anatomical and systematic inquiry.
-
-Now if, by means of comparative anatomy and ontogeny, we seek for man's
-position in that Natural System of animals which formed the subject of
-the last two chapters, the incontrovertible fact will at once present
-itself to us, that man belongs to the tribe, or phylum, of the
-Vertebrata. Every one of the characteristics, which so strikingly
-distinguish all the Vertebrata from all Invertebrata, is possessed by
-him. It has also never been doubted that of all the Vertebrata the
-Mammals are most closely allied to Man, and that he possesses all the
-characteristic features distinguishing them from all other Vertebrata.
-If then we further carefully examine the three different main groups or
-sub-classes of Mammals--the inter-connections of which were discussed in
-our last chapter--there cannot be the slightest doubt that Man belongs
-to the Placentals, and shares with all other Placentals, the important
-characteristics which distinguish them from Marsupials and from
-Cloacals. Finally, of the two main groups of placental Mammals, the
-Deciduata and the Indeciduata, the group of Deciduata doubtless includes
-Man. For the human embryo is developed with a genuine decidua, and is
-thus absolutely distinguished from all the Indeciduata. Among the
-Deciduata we distinguish two legions, the Zonoplacentalia, with
-girdle-shaped placenta (Beasts of Prey and Pseudo-hoofed animals), and
-the Discoplacentalia, with disc-shaped placenta (all the remaining
-Deciduata). Man possesses a disc-shaped placenta, like all
-Discoplacentalia; and thus our next question must be, What is man's
-position in this group?
-
-In the last chapter we distinguished the following five orders of
-Discoplacentalia: (1) Semi-apes; (2) Rodents; (3) Insectivora; (4) Bats;
-(5) Apes. The last of these five orders, that of Apes, is, as every one
-knows, in every bodily feature far more closely allied to Man than the
-four others. Hence the only remaining question now is, whether, in the
-system of animals, Man is to be directly classed in the order of genuine
-Apes, or whether he is to be considered as the representative of a
-special sixth order of Discoplacentalia, allied to, but more advanced
-than, that of the Apes.
-
-Linnæus in his system classed Man in the same order with genuine Apes,
-Semi-apes, and Bats, which he called _Primates_; that is, lords, as it
-were the highest dignitaries of the animal kingdom. But Blumenbach, of
-Göttingen, separated Man as a special order, under the name of _Bimana_,
-or two-handed, and contrasted him with the Apes and Semi-apes under the
-name of _Quadrumana_, or four-handed. This classification was also
-adopted by Cuvier and, consequently, by most subsequent zoologists. It
-was not until 1863 that Huxley, in his excellent work, the "Evidence as
-to Man's Place in Nature,"(26) showed that this classification was based
-upon erroneous ideas, and that the so-called "four-handed" Apes and
-Semi-apes are "two-handed" as much as man is himself. The difference
-between the foot and hand does not consist in the _physiological_
-peculiarity that the first digit or thumb is opposable to the four other
-digits or fingers in the hand, and is not so in the foot, for there are
-wild tribes of men who can oppose the first or large toe to the other
-four, just as if it were a thumb. They can therefore use their "grasping
-foot" as well as a so-called "hinder hand," like Apes. The Chinese
-boatmen row with this hinder hand, the Bengal workmen weave with it. The
-Negro, in whom the big toe is especially strong and freely moveable,
-when climbing seizes hold of the branches of the trees with it, just
-like the "four-handed" Apes. Nay, even the newly born children of the
-most highly developed races of men, during the first months of their
-life, grasp as easily with the "hinder hand" as with the "fore hand,"
-and hold a spoon placed in its clutch as firmly with their big toe as
-with the thumb! On the other hand, among the higher Apes, especially the
-gorilla, hand and foot are differentiated as in man. (Compare Plate IV.)
-
-The essential difference between hand and foot is therefore not
-physiological, but _morphological_, and is determined by the
-characteristic structure of the bony skeleton and of the muscles
-attached to it. The ankle-bones differ from the wrist-bones in
-arrangement, and the foot possesses three special muscles not existing
-in the hand (a short flexor muscle, a short extensor muscle, and a long
-fibular muscle). In all these respects, Apes and Semi-apes entirely
-agree with man, and hence it was quite erroneous to separate him from
-them as a special order on account of the stronger differentiation of
-his hand and foot. It is the same also with all the other structural
-features by means of which it was attempted to distinguish Man from
-Apes; for example, the relative length of the limbs, the structure of
-the skull, of the brain, etc. In all these respects, without exception,
-the differences between Man and the higher Apes are less than the
-corresponding differences between the higher and the lower Apes. Hence
-Huxley, for reasons based on the most careful and most accurate
-anatomical comparisons, arrives at the extremely important
-conclusion--"Thus, whatever system of organs be studied, the comparison
-of their modifications in the Ape series leads to one and the same
-result, that the structural differences which separate Man from the
-Gorilla and Chimpanzee are not so great as those which separate the
-Gorilla from the lower Apes." In accordance with this, Huxley, strictly
-following the demands of logic, classes Man, Apes, and Semi-apes in a
-single order, _Primates_, and divides it into the following seven
-families, which are of almost equal systematic value: (1) Anthropini
-(Man); (2) Catarrhini (genuine Apes of the Old World); (3) Platyrrhini
-(genuine American Apes); (4) Arctopitheci (American clawed Apes); (5)
-Lemurini (short-footed and long-footed Semi-apes, p. 255); (6)
-Chiromyini (p. 256); (7) Galeopithecini (Flying Lemurs, p. 256).
-
-
-SYSTEMATIC SURVEY
-
-_Of the Families and Genera of Apes._
-
-
-  -----------------+------------------------+---------------------+------------------
-    _Sections_     |      _Families_        |      _Genera_       | _Systematic Name_
-       _of_        |         _of_           |        _of_         |       _of_
-      _Apes._      |        _Apes._         |       _Apes._       |  _the Genera._
-  -----------------+------------------------+---------------------+------------------
-  I. APES OF THE NEW WORLD (+Hesperopitheci+), OR FLAT-NOSED APES (+Platyrrhini+).
-  -----------------------------------------------------------------------------------
-  A. =Platyrrhini=  {  I. Silky apes         {  1. Brush ape        1. Midas
-    =with claws=    {    _Hapalida_          {  2. Lion ape         2. Jacchus
-                    {
-  +Arctopitheci+    {
-
-                    {  II. Flat-nosed,       {  3. Squirrel ape     3. Chrysothrix
-                    { without prehensile     {  4. Leaping ape      4. Callithrix
-  B. =Platyrrhini=  {       tail             {  5. Nocturnal ape    5. Nyctipithecus
-    =with blunt=    {    _Aphyocerca_        {  6. Tail ape         6. Pithecia
-       =nails=      {
-                    {  III. Flat-nosed,      {  7. Rolling ape      7. Cebus
-  +Dysmopitheci+    {  with prehensile       {  8. Climbing ape     8. Ateles
-                    {      tail              {  9. Woolly ape       9. Lagothrix
-                    {  _Labidocerca_         { 10. Howling ape     10. Mycetes
-  ----------------------------------------------------------------------------------
-  II. APES OF THE OLD WORLD (+Heopitheci+), OR NARROW-NOSED APES (+Catarrhini+).
-  ----------------------------------------------------------------------------------
-                    { IV. Tailed Catarrhini, {
-                    {          with          { 11. Pavian          11. Cynocephalus
-  C. =Tailed=       {     cheek-pouches      { 12. Macaque         12. Innus
-  =Catarrhini=      {      _Ascoparea_       { 13. Sea cat         13. Cercopithecus
-                    {
-  +Menocerca+       { V. Tailed Catarrhini,  {
-                    {        without         { 14. Holy ape        14. Semnopithecus
-                    {     cheek-pouches      { 15. Short ape       15. Colobus
-                    {       _Anasca_         { 16. Nose ape        16. Nasalis
-
-                    {                        { 17. Gibbon          17. Hylobates
-                    {  VI. Human apes        { 18. Orang-Outan     18. Satyrus
-  D. =Tailless=     {   _Anthropoides_       { 19. Chimpanzee      19. Engeco
-  =Catarrhini=      {                        { 20. Gorilla         20. Gorilla
-                    {
-  +Lipocerca+       {     VII. Men           { 21. Ape-like man,   21. Pithecanthropus
-                    {      _Erecti_          { or speechless man         (Alalus)
-                    {    (_Anthropi_)        { 22. Talking man     22. Homo
-
-             ----------------------------------------------------------------
-
-                                       Straight-haired men
-                                          _Lissotrichi_
-                                                |
-             Woolly-haired men                  |
-               _Ulotrichi_                      |
-                    |                           |
-                    |                           |
-                    \-------------v-------------/
-                     Speechless men (_Alali_), or
-                    Ape-like men (_Pithecanthropi_)
-                                  |
-                       Gorilla    |
-                      _Gorilla_   |     Orang
-        Chimpanzee        |       |   _Satyrus_
-        _Engeco_          |       |       |     Gibbon
-            |             |       |       |   _Hylobates_
-            |             |       |       |        |
-            \------v------/       |       |        |
-                African           \-------v--------/
-              Man-like Apes            Asiatic
-                   |                Man-like Apes
-                   |                      |
-                   \----------v-----------/
-                        =Man-like Apes=                    Nose apes
-                        +Anthropoides+                   _Nasalis_
-                              |                              |
-    Silk apes                 |             Tall apes        |
-  _Arctopitheci_              |           _Semnopithecus_    |
-        |        Clutch-tails |                 |            |
-        |       _Labidocerca_ |                 |            |
-        |             |       |                 \-v----------/
-        |             |       |     Sea cat       |       Pavian
-        \-----v-------/       | _Cercopithecus_   |    _Cynocephalus_
-           Flap-tails         |       |           |         |
-          _Aphyocerca_        |       |           |         |
-                              \--------------v--------------/
-        =Flat-nosed Apes=           Tailed Narrow-nosed apes
-        +Platyrrhini+              _Catarrhina menocerca_
-              |                        =Narrow-nosed=
-              |                        +Catarrhini+
-              |                              |
-              |                              |
-              \--------------v---------------/
-                           =Apes=
-                          +Simiæ+
-                             |
-                             |
-                         Semi-apes
-                         _Prosimiæ_
-
-
-If we wish to arrive at a natural system, and consequently at the
-pedigree of the Primates, we must go a step further still, and entirely
-separate the Semi-apes, or Prosimiæ, (Huxley's last three families),
-from Genuine Apes, or Simiæ (the first four families). For, as I have
-already shown in my General Morphology, and explained in the last
-chapter, the Semi-apes differ in many and important respects from
-Genuine Apes, and in their individual forms are more closely allied to
-the various other orders of Discoplacentalia. Hence the Semi-apes must
-probably be considered as the remnants of the common primary group, out
-of which the other orders of Discoplacentalia, and, it may be, all
-Deciduata, have developed as two diverging branches. (Gen. Morph. ii.
-pp. 148 and 153.) But man cannot be separated from the order of Genuine
-Apes, or Simiæ, as he is in every respect more closely allied to the
-higher Genuine Apes than the latter are to the lower Genuine Apes.
-
-_Genuine Apes_ (Simiæ) are universally divided into two perfectly
-natural groups, namely, the Apes of the New World, or American Apes, and
-the Apes of the Old World, which are indigenous to Asia and Africa, and
-which formerly also existed in Europe. These two classes differ
-principally in the formation of the nose, and they have been named
-accordingly. American Apes have flat noses, so that the nostrils are in
-front, not below; hence they are called _Flat Noses_ (Platyrrhini). On
-the other hand, the Apes of the Old World have a narrow cartilaginous
-bridge, and the nostrils turned downwards, as in man; they are,
-therefore, called _Narrow Noses_ (Catarrhini). Further, the jaw, which
-plays an important part in the classification of Mammals, is essentially
-distinct in these two groups. All Catarrhinæ, or Apes of the Old World,
-have exactly the same jaws as Man, namely, in each jaw four incisors
-above and below, then on each side a canine tooth and five cheek teeth,
-of which two are pre-molars and three molars, altogether thirty-two
-teeth. But all Apes of the New World, all Platyrrhini, have four more
-cheek teeth, namely, three pre-molars and three molars on each side,
-above and below: they consequently possess thirty-six teeth. Only one
-small group forms an exception to this rule, namely, the _Arctopitheci_,
-or _Clawed Apes_, in whom the third molar has degenerated, and they
-accordingly have on each half of their jaw three pre-molars and two
-molars. They also differ from the other Platyrrhini by having claws on
-the fingers of their hands and the toes of their feet, not nails like
-Man and the other Apes. This small group of South American Apes, which
-includes among others the well-known pretty little Midas-monkey and the
-Jacchus, must probably be considered only as a peculiarly developed
-lateral branch of the Platyrrhini.
-
-Now, if we ask what evidence can be drawn, as to the pedigree of Apes,
-from the above facts, we must conclude that all the Apes of the New
-World have developed out of one tribe, for they all possess the
-characteristic jaw and the nasal formation of the Platyrrhini. In like
-manner it follows that all the Apes of the Old World must be derived
-from one and the same common primary form, which possessed the same
-formation of nose and jaw as all the still living Catarrhini. Further,
-it can scarcely be doubted that the Apes of the New World, taken as an
-entire tribe, are either derived from those of the Old World, or (to
-express it more vaguely and cautiously) both are diverging branches of
-one and the same tribe of Apes. We also arrive at the exceedingly
-important conclusion--which is of the utmost significance in regard to
-Man's distribution on the earth's surface--that Man _has developed out
-of the Catarrhini_. For we cannot discover a zoological character
-distinguishing him in a higher degree from the allied Apes of the Old
-World than that in which the most divergent forms of this group are
-distinguished from one another. This is the important result of Huxley's
-careful anatomical examination of the question, and it cannot be too
-highly estimated. The anatomical differences between Man and the most
-human-like Catarrhini (Orang, Gorilla, Chimpanzee) are in every respect
-less than the anatomical differences between the latter and the lowest
-stages of Catarrhini, more especially the Dog-like Baboon. This
-exceedingly important conclusion is the result of an impartial
-anatomical comparison of the different forms of Catarrhini.
-
-If, therefore, we recognise the natural system of animals as the guide
-to our speculations, and establish upon it our pedigree, we must
-necessarily come to the conclusion that _the human race is a small
-branch of the group of Catarrhini, and has developed out of long since
-extinct Apes of this group in the Old World_. Some adherents of the
-Theory of Descent have thought that the American races of Men have
-developed, independently of those of the Old World, out of American
-Apes. I consider this hypothesis to be quite erroneous, for the complete
-agreement of all mankind with the Catarrhini, in regard to the
-characteristic formation of the nose and jaws, distinctly proves that
-they are of the same origin, and that they developed out of a common
-root after the Platyrrhini, or American Apes, had already branched off
-from them. The primæval inhabitants of America, as is proved by numerous
-ethnographical facts, immigrated from Asia, and partly perhaps from
-Polynesia (or even from Europe).
-
-There still exist great difficulties in establishing an accurate
-pedigree of the Human Race; this only can we further assert, that the
-nearest progenitors of man were tail-less Catarrhini (Lipocerca),
-resembling the still living Man-like Apes. These evidently developed at
-a late period out of tailed Catarrhini (Menocerca), the original form of
-Ape. Of those tail-less Catarrhini, which are now frequently called
-Man-like Apes, or Anthropoides, there still exist four different genera
-containing about a dozen different species.
-
-The largest Man-like Ape is the famous _Gorilla_ (called Gorilla engena,
-or Pongo gorilla), which is indigenous to the tropics of western Africa,
-and was first discovered by the missionary, Dr. Savage, in 1847, on the
-banks of the river Gaboon. Its nearest relative is the _Chimpanzee_
-(Engeco troglodytes, or Pongo troglodytes), also indigenous to western
-Africa, but considerably smaller than the Gorilla, which surpasses man
-in size and strength. The third of the three large Man-like Apes is the
-_Orang_, or _Orang Outang_, indigenous to Borneo and the other Sunda
-Islands, of which two kindred species have recently been distinguished,
-namely, the large Orang (Satyrus orang, or Pithecus satyrus) and the
-small Orang (Satyrus morio, or Pithecus morio). Lastly, there still
-exists in southern Asia the genus _Gibbon_ (Hylobates), of which from
-four to eight different species are distinguished. They are considerably
-smaller than the three first-named Anthropoides, and in most
-characteristics differ more from Man.
-
-The tail-less Man-like Apes--especially since we have become more
-intimately acquainted with the Gorilla, and its connection with Man by
-the application of the Theory of Descent--have excited such universal
-interest, and called forth such a flood of writings, that there is no
-occasion for me here to enter into any detail about them. The reader
-will find their relations to Man fully discussed in the excellent works
-of Huxley,(26) Carl Vogt,(27) Büchner,(43) and Rolle.(28) I shall
-therefore confine myself to stating the most important general
-conclusion resulting from their thorough comparison with Man, namely,
-that each one of the four Man-like Apes stands nearer to Man in one or
-several respects than the rest, but that no one of them can in every
-respect be called absolutely the most like Man. The Orang stands nearest
-to Man in regard to the formation of the brain, the Chimpanzee in
-important characteristics in the formation of the skull, the Gorilla in
-the development of the feet and hands, and, lastly, the Gibbon in the
-formation of the thorax.
-
-Thus, from a careful examination of the comparative anatomy of the
-Anthropoides, we obtain a similar result to that obtained by Weisbach,
-from a statistical classification and a thoughtful comparison of the
-very numerous and careful measurements which Scherzer and Schwarz made
-of the different races of Men during their voyage in the Austrian
-frigate _Novara_ round the earth. Weisbach comprises the final result of
-his investigations in the following words: "_The ape-like
-characteristics of Man_ are by no means concentrated in one or another
-race, but are distributed in particular parts of the body, among the
-different races, in such a manner that each is endowed with some
-heirloom of this relationship--one race more so, another less, and even
-we Europeans cannot claim to be entirely free from evidences of this
-relationship."[5]
-
-I must here also point out, what in fact is self-evident, that not one
-of all the still living Apes, and consequently not one of the so-called
-Man-like Apes, can be the progenitor of the Human Race. This opinion, in
-fact, has never been maintained by thoughtful adherents of the Theory of
-Descent, but it has been assigned to them by their thoughtless
-opponents. The Ape-like progenitors of the Human Race are long since
-extinct. We may possibly still find their fossil bones in the tertiary
-rocks of southern Asia or Africa. In any case they will, in the
-zoological system, have to be classed in the group of _tail-less
-Narrow-nosed Apes_ (Catarrhini Lipocerci, or Anthropoides).
-
-The genealogical hypotheses, to which we have thus far been led by the
-application of the Theory of Descent to Man, present themselves to every
-clearly and logically reasoning person as the direct results from the
-facts of comparative anatomy, ontogeny, and palæontology. Of course our
-phylogeny can indicate only in a very general way the outlines of the
-human pedigree. Phylogeny is the more in danger of becoming erroneous
-the more rigorously it is applied in detail to special animal forms
-known to us. However, we can, even now, with approximate certainty
-distinguish at least the following twenty-two stages of the ancestors of
-Man. Fourteen of these stages belong to the Vertebrata, and eight to the
-Invertebrate ancestors of Man (Prochordata.)
-
-
-THE CHAIN OF THE ANIMAL ANCESTORS, OR THE SERIES OF THE PROGENITORS, OF
-MAN.
-
-(Comp. Ch. XX., XXI.; Plate XIV. and p. 22.)
-
-FIRST HALF OF THE SERIES OF THE ANCESTORS OF MAN.
-
-INVERTEBRATE ANCESTORS OF MAN (Prochordata).
-
-FIRST STAGE: +Monera+.
-
-The most ancient ancestors of Man, as of all other organisms, were
-living creatures of the simplest kind imaginable, _organisms without
-organs_, like the still living Monera. They consisted of simple,
-homogeneous, structureless and formless little lumps of mucous or
-albuminous matter (protoplasm), like the still living Protamoeba
-primitiva. (Compare vol. i. p. 186, Fig. 1.) The _form value_ of these
-most ancient ancestors of man was not even equal to that of a cell, but
-merely that of a _cytod_ (compare vol. i. p. 347); for, as in the case
-of all Monera, the little lump of protoplasm did not as yet possess a
-cell-kernel. The first of these Monera _originated_ in the beginning of
-the Laurentian period by _spontaneous generation_, or archigony, out of
-so-called "inorganic combinations," namely, out of simple combinations
-of carbon, oxygen, hydrogen, and nitrogen. The assumption of this
-spontaneous generation, that is, of a mechanical origin of the first
-organisms from inorganic matter, has been proved in our thirteenth
-chapter to be a necessary hypothesis. (Compare vol. i. p. 338.) A
-direct _proof_ of the earlier existence of this most ancient ancestral
-stage, based upon the fundamental law of biogeny, is possibly still
-furnished by the circumstance that, according to the assertions of many
-investigators, in the beginning of the development of the egg, the
-cell-kernel, or nucleus, disappears, and the egg-cell thus relapses to
-the lower stage of the cytod (Monerula, p. 124; _relapse_ of the
-nucleated plastid into a non-nucleated condition). The assumption of
-this first stage is necessary for most important general reasons.
-
-
-SECOND STAGE: +Amoebæ+.
-
-The second ancestral stage of Man, as of all the higher animals and
-plants, is formed by _a simple cell_, that is, a little piece of
-protoplasm enclosing a kernel. There still exist large numbers of
-similar "single-celled organisms." Among them the common, simple Amoebæ
-(vol. i. p. 188, Fig. 2) cannot have been essentially different from
-these progenitors. The _form value_ of every Amoeba is essentially the
-same as that still possessed by the egg of Man, and by the egg of all
-other animals. (Vol. i. p. 189, Fig. 3.) The naked egg-cells of Sponges,
-which creep about exactly like Amoebæ, cannot be distinguished from
-them. The egg-cell of Man, which like that of most other animals is
-surrounded by a membrane, resembles an enclosed Amoeba. The first
-single-celled animals of this kind arose out of Monera by the
-differentiation of the inner kernel and the external protoplasm; they
-lived in the earlier Primordial period. An irrefutable proof that such
-single-celled primæval animals really existed as the direct ancestors of
-Man, is furnished according to the fundamental law of biogeny (vol. i.
-p. 309) by the fact that the human egg is nothing more than a simple
-cell. (Compare p. 124.)
-
-
-THIRD STAGE: +Synamoebæ+.
-
-In order to form an approximate conception of the organisation of those
-ancestors of Man which first developed out of the single-celled Primæval
-animals, it is necessary to trace the changes undergone by the human egg
-in the beginning of its individual development. It is just here that
-ontogeny guides us with the greatest certainty on to the track of
-phylogeny. We have already seen that the egg of Man (in the same way as
-that of all other Mammals), after fructification has taken place, falls
-by self-division into a mass of simple and equi-formal Amoeba-like cells
-(vol. i. p. 190, Fig. 4 _D_). All these divided globules are at first
-exactly like one another, naked cells containing a kernel, but without
-covering; in many animals they show movements like those of the Amoebæ.
-This ontogenetic stage of development which we called Morula (p. 125),
-on account of its mulberry shape, is _a certain proof_ that in the early
-primordial period there existed ancestors of man which possessed the
-_form value_ of a mass of homogeneous, loosely connected cells. They may
-be called a _community of Amoebæ_ (Synamoebæ). (Compare p. 127.) They
-_originated_ out of the single-celled Primæval animals of the second
-stage by repeated self-division and by the permanent union of the
-products of this division.
-
-
-FOURTH STAGE: +Ciliated Larva (Planæada)+.
-
-In the course of the ontogenesis of most of the lower animals, and also
-in that of the lowest Vertebrate animals, the Lanceolate Animals, or
-Amphioxus, there first develops out of the Morula (Frontispiece, Fig. 3)
-a ciliated larva (planula). Those cells, lying on the surface of the
-homogeneous mass of cells, extend hair-like processes, or fringes of
-hairs, which by striking against the water keep the whole body rotating.
-The round many-celled body thus becomes differentiated, in that the
-external cells covered with cilia differ from the non-ciliated internal
-cells (Frontispiece, Fig. 4). In Man and in all other Vertebrate animals
-(with the exception of the Amphioxus), as well as in all Arthropoda,
-this stage of the ciliated larva has been lost, in the course of time,
-by abbreviated inheritance. There must, however, have existed ancestors
-of Man in the early Primordial period which possessed the form value of
-these ciliated larvæ (Planæa, p. 125). A certain proof of this is
-furnished by the Amphioxus, which is on the one hand related by blood to
-Man, but on the other has retained down to the present day the stage of
-the planula.
-
-
-FIFTH STAGE: +Primæval Stomach Animals (Gastræada)+.
-
-In the course of the individual development of Amphioxus, as well as in
-the most different lower animals, there first arises out of the planula
-the extremely important form of larva which we have named _stomach
-larva_, or _gastrula_ (p. 126; Frontispiece, Fig. 5, 6). According to
-the fundamental law of biogeny this gastrula proves the former existence
-of an independent form of primæval animal of the same structure, and
-this we have named primæval stomach animal, or Gastræa (pp. 127, 128).
-These Gastræada must have existed during the older Primordial period,
-and they must have also included the ancestors of man. A _certain
-proof_ of this is furnished by the Amphioxus, which in spite of its
-blood relationship to Man still passes through the stage of the gastrula
-with a simple intestine and a double intestinal wall. (Compare Plate X.
-Fig. _B 4_.)
-
-
-SIXTH STAGE: +Gliding Worms (Turbellaria)+.
-
-The human ancestors of the sixth stage which originated out of the
-Gastræada of the fifth stage, were low worms, which, of all the forms of
-worms known to us, were most closely allied to the Gliding Worms, or
-Turbellaria, or at least upon the whole possessed their form value. Like
-the Turbellaria of the present day, the whole surface of their body was
-covered with cilia, and they possessed a simple body of an oval shape,
-entirely without appendages. These acoelomatous worms did not as yet
-possess a true body-cavity (coelom) nor blood. They _originated_ in the
-early primordial period out of the Gastræada, by the formation of a
-middle germ-layer, or muscular layer, and also by the further
-differentiation of the internal parts into various organs; more
-especially the first formation of a nervous system, the simplest organs
-of sense, the simplest organs for secretion (kidneys) and generation
-(sexual organs). The proof that human ancestors existed of a similar
-formation, is to be looked for in the circumstance that comparative
-anatomy and ontogeny point to the lower acoelomatous Worms as the common
-primary form, not merely of all higher Worms, but also of the four
-higher tribes of animals. Now, of all the animals known to us, the
-Turbellaria, which possess neither a body-cavity nor blood, are most
-closely allied to these primæval acoelomatous Primary Worms.
-
-
-SEVENTH STAGE: +Soft Worms (Scolecida)+.
-
-Between the Turbellaria of the preceding stage and the Sack Worms of the
-next stage, we must necessarily assume at least one connecting
-intermediate stage. For the Tunicata, which of all known animals stand
-nearest to the eighth stage, and the Turbellaria which most resemble the
-sixth stage, indeed both belong to the lower division of the unsegmented
-Worms; but still these two divisions differ so much from one another in
-their organization, that we must necessarily assume the earlier
-existence of extinct intermediate forms between the two. These
-connecting links, of which no fossil remains exist, owing to the soft
-nature of their bodies, we may comprise as _Soft Worms_, or Scolecida.
-They developed out of the Turbellaria of the sixth stage by forming a
-true body-cavity (a coelom) and blood in their interior. It is difficult
-to say which of the still living Coelomati are nearest akin to these
-extinct Scolecida; it may be the Acorn-worms (Balanoglossus). The proof
-that even the direct ancestors of man belonged to these Scolecida, is
-furnished by the comparative anatomy and the ontogeny of Worms and of
-the Amphioxus. The form value of this stage must moreover have been
-represented by several very different intermediate stages, in the wide
-gap between Turbellaria and Tunicata.
-
-
-EIGHTH STAGE: +Sack Worms (Himatega)+.
-
-Under the name of Sack worms, or Himatega, we here allude in the eighth
-place to those Coelomati, out of which the most ancient skull-less
-Vertebrata were directly developed. Among the Coelomati of the present
-day, the _Ascidians_ are the nearest relatives of these exceedingly
-remarkable Worms, which connect the widely differing classes of
-Invertebrate and Vertebrate animals. That the ancestors of man really
-existed during the primordial period in the form of these Himatega, is
-_distinctly proved_ by the exceedingly remarkable and important
-agreement presented by the ontogeny of the Amphioxus and the Ascidia.
-(Compare Plates XII. and XIII., also pp. 152, 200, etc.) From this fact
-the earlier existence of Sack Worms may be inferred; they of all known
-worms were most closely related to our recent Tunicates, especially to
-the freely swimming young forms or larvæ of the simple Sea-squirts
-(Ascidia, Phallusia). They originated out of the worms of the seventh
-stage by the formation of a dorsal nerve-marrow (medulla tube), and by
-the formation of the spinal rod (chorda dorsalis) which lies below it.
-It is just the position of this central spinal rod, or axial skeleton,
-between the dorsal marrow on the dorsal side, and the intestinal canal
-on the ventral side, which is most characteristic of all Vertebrate
-animals, including man, but also of the larvæ of the Ascidia. The form
-value of this stage nearly corresponds with that which the larvæ of the
-simple Sea-squirts possess at the time when they show the beginning of
-the dorsal marrow and spinal rod. (Plate XII. Fig. _A 5_: compare the
-explanation of these figures in the Appendix.)
-
-
-SECOND HALF OF THE SERIES OF HUMAN ANCESTORS. VERTEBRATE ANIMAL
-ANCESTORS OF MAN (Vertebrata).
-
-NINTH STAGE: +Skull-less Animals (Acrania)+.
-
-The series of human ancestors, which in accordance with their whole
-organisation we have to consider as Vertebrate animals, begins with the
-Skull-less animals, or Acrania, of whose nature the still living
-Lancelet (Amphioxus lanceolatus, Plate XII. _B_, XIII. _B_) gives us a
-faint idea. Since this little animal in its earliest embryonal state
-entirely agrees with the Ascidia, and in its further development shows
-itself to be a true Vertebrate animal, it forms a direct transition from
-the Vertebrata to the Invertebrata. Even if the human ancestors of the
-ninth stage in many respects differed from the Amphioxus--the last
-surviving representative of the Skull-less animals--yet they must have
-resembled it in its most essential characteristics, in the absence of
-head, skull, and brain. Skull-less animals of such structure--out of
-which animals with skulls developed at a later period--lived during the
-primordial period, and originated out of the Himatega of the eighth
-stage by the formation of the metamera, or body segments, as also by the
-further differentiation of all organs, especially the more perfect
-development of the dorsal nerve-marrow and the spinal rod lying below
-it. Probably the separation of the two sexes (gonochorism) also began at
-this stage, whereas all the previously mentioned invertebrate ancestors
-(apart from the 3--4 first neutral stages) exhibited the condition of
-hermaphrodites (hermaphroditism). (Compare vol. i. p. 196.) The _certain
-proof_ of the former existence of these skull-less and brainless
-ancestors of man, is furnished by the comparative anatomy and the
-ontogeny of the Amphioxus and of the Craniota.
-
-
-TENTH STAGE: +Single-nostriled Animals (Monorrhina)+.
-
-Out of the Skull-less ancestors of man there arose in the first place
-animals with skulls, or Craniota, of the most imperfect nature. The
-lowest stage of all still living Craniota is occupied by the class of
-round-mouthed animals, or Cyclostoma, namely, the Hag (Myxinoidea) and
-Lampreys (Petromyzontia). From the internal organization of these
-single-nostriled animals, or Monorrhina, we can form an approximate idea
-of the nature of the human ancestors of the tenth stage. In the former,
-as also in the latter, skull and brain must have been of the simplest
-form, and many important organs, as for example, the swimming bladder,
-the sympathetic nerve, the spleen, the jaw skeleton, and both pairs of
-legs, may probably as yet not have existed. However, the pouch gills and
-the round sucking mouth of the Cyclostoma must probably be looked upon
-as purely adaptive characteristics, which did not exist in the
-corresponding stage of ancestors. The single-nostriled animals
-originated during the primordial period out of the skull-less animals by
-the anterior end of the dorsal marrow developing into the brain, and the
-anterior end of the dorsal chord into the skull. The _certain proof_
-that such single-nostriled and jawless ancestors of man did exist, is
-found in the "comparative anatomy of the Myxinoidea."
-
-
-ELEVENTH STAGE: +Primæval Fish (Selachii.)+.
-
-Of all known Vertebrate animals, the ancestors of the Primæval Fish
-probably showed most resemblance to the still living Sharks (Squalacei).
-They _originated_ out of the single-nostriled animals by the division of
-the single nostril into two lateral halves, by the formation of a
-sympathetic nervous system, a jaw skeleton, a swimming bladder, and two
-pairs of legs (breast fins or fore-legs, and ventral fins or hind-legs).
-The internal organisation of this stage may probably, upon the whole,
-have corresponded to the lowest species of Sharks known to us; the
-swimming bladder was however more strongly developed; in the case of the
-latter it exists only as a rudimentary organ. They _lived_ as early as
-the Silurian period, as is proved by the fossil remains of sharks (teeth
-and fin spines) from the Silurian strata. A _certain proof_ that the
-Silurian ancestors of man and of all the other double-nostriled animals
-were nearest akin to the Selachii, is furnished by the comparative
-anatomy of the latter; it shows that the relations of organisation in
-all Amphirrhina can be derived from those of the Selachii.
-
-
-TWELFTH STAGE: +Mud Fish (Dipneusta)+.
-
-Our twelfth ancestral stage is formed by Vertebrate animals which
-probably possessed a remote resemblance to the still living Salamander
-fish (Ceratodus, Protopterus, Lepidosiren, p. 212). They _originated_
-out of the Primæval fish (probably at the beginning of the palæolithic,
-or primary period) by adaptation to life on land, and by the
-transformation of the swimming bladder into an air-breathing lung, and
-of the nasal cavity (which now opened into the cavity of the mouth)
-into air passages. The series of the ancestors of man which breathed air
-through lungs began at this stage. Their organisation may probably in
-many respects have agreed with that of the still living Ceratodus and
-Protopterus, but at the same time may have been very different. They
-probably lived at the beginning of the Devonian period. Their existence
-is _proved_ by comparative anatomy, which shows the Dipneusta to be an
-intermediate stage between the Selachii and Amphibia.
-
-
-THIRTEENTH STAGE: +Gilled Amphibians (Sozobranchia)+.
-
-Out of those Mud Fish, which we considered the primary forms of all the
-Vertebrata which breathe through lungs, there developed the class of
-Amphibia as the main line (pp. 205, 216). Here began the five-toed
-formation of the foot (the Pentadactyla), which was thence transmitted
-to the higher Vertebrata, and finally also to Man. The gilled Amphibians
-must be looked upon as our most ancient ancestors of the class of
-Amphibia; besides possessing lungs they retained throughout life regular
-gills, like the still living Proteus and Axolotl (p. 218). They
-_originated_ out of the Dipneusta by the transformation of the paddling
-fins into five-toed legs, and also by the more perfect differentiation
-of various organs, especially of the vertebral column. In any case they
-existed about the middle of the palæolithic, or primary period, possibly
-even before the Coal period; for fossil Amphibia are found in coal. The
-_proof_ that similar gilled Amphibians were our direct ancestors, is
-given by the comparative anatomy and the ontogeny of Amphibia and
-Mammals.
-
-
-FOURTEENTH STAGE: +Tailed Amphibians (Sozura)+.
-
-Our amphibious ancestors which retained their gills throughout life,
-were replaced at a later period by other Amphibia, which, by
-metamorphosis, lost the gills which they had possessed in early life,
-but retained the tail, as in the case of the salamanders and newts of
-the present day. (Compare p. 218.) They _originated_ out of the gilled
-Amphibians by accustoming themselves in early life to breathe only
-through gills, and later in life only through lungs. They probably
-existed even in the second half of the primary, namely, during the
-Permian period, but possibly even during the Coal period. The _proof_ of
-their existence lies in the fact that tailed Amphibians form a necessary
-intermediate link between the preceding and succeeding stages.
-
-
-FIFTEENTH STAGE: +Primæval Amniota (Protamnia)+.
-
-The name Protamnion we have given to the primary form of the three
-higher classes of Vertebrate animals, out of which the Proreptilia and
-the Promammalia developed as two diverging branches (p. 222). It
-_originated_ out of unknown tailed Amphibia by the complete loss of the
-gills, by the formation of the amnion, of the cochlea, and of the round
-window in the auditory organ, and of the organs of tears. It probably
-originated in the beginning of the mesolithic or secondary period,
-perhaps even towards the end of the primary, in the Permian period. The
-_certain proof_ that it once existed lies in the comparative anatomy and
-the ontogeny of the Amniota; for all Reptiles, Birds, and Mammals,
-including Man, agree in so many important characteristics that they
-must, with full assurance, be admitted to be the descendants of a
-single common primary form, namely, of the Protamnion.
-
-
-SIXTEENTH STAGE: +Primary Mammals (Promammalia)+.
-
-We now find ourselves more at home with our ancestors. From the
-sixteenth up to the twenty-second stage they all belong to the large and
-well known class of Mammals, the confines of which we ourselves have as
-yet not transgressed. The common, long since extinct and unknown primary
-forms of all Mammalia, which we have named Promammalia, were at all
-events, of all still living animals, of the class most closely related
-to the Beaked animals, or Ornithostoma (Ornithorhynchus, Echidna, p.
-233). They differed from the latter, however, by the teeth present in
-their jaws. The formation of the beak in the Beaked animals of the
-present day must be looked upon as an adaptive characteristic which
-developed at a later period. The Promammalia arose out of the Protamnia
-(probably only at the beginning of the secondary period, namely, in the
-Trias) by various advances in their internal organisation, as also by
-the transformation of the epidermal scales into hairs, and by the
-formation of a mammary gland which furnished milk for the nourishment of
-the young ones. The _certain proof_ that the Promammalia--inasmuch as
-they are the common primary forms of all Mammals--also belong to our
-ancestors, lies in the comparative anatomy and the ontogeny of Mammalia
-and Man.
-
-
-SEVENTEENTH STAGE: +Pouched Animals (Marsupialia)+.
-
-The three sub-classes of Mammalia--as we have already seen--stand in
-such a relation to one another that the Marsupials, both as regards
-their anatomy and their ontogeny and phylogeny, form the direct
-transition from the Monotrema to Placental animals (p. 247).
-Consequently, human ancestors must also have existed among Marsupials.
-They _originated_ out of the Monotrema--which include the primary
-Mammalia, or Promammalia--by the division of the cloaca into the rectum
-and the urogenital sinus, by the formation of a nipple on the mammary
-gland, and by the partial suppression of the clavicles. The oldest
-Marsupials at all events existed as early as the Jura period (perhaps
-even in the Trias); during the Chalk period they passed through a series
-of stages preparing the way for the origin of Placentalia. The certain
-proof of our derivation from Marsupials--nearly akin to the still living
-opossum and kangaroo in their essential inner structure--is furnished by
-the comparative anatomy and the ontogeny of Mammalia.
-
-
-EIGHTEENTH STAGE: +Semi-apes (Prosimiæ)+.
-
-The small group of Semi-apes, as we have already seen, is one of the
-most important and most interesting orders of Mammalia. It contains the
-direct primary forms of Genuine Apes, and thus also of Man. Our Semi-ape
-ancestors probably possessed only a very faint external resemblance to
-the still living, short-footed Semi-apes (Brachytarsi), especially the
-Maki, Indri, and Lori (p. 256). They _originated_ (probably at the
-beginning of the Cenolithic, or Tertiary period) out of Marsupials of
-Rat-like appearance by the formation of a placenta, the loss of the
-marsupium and the marsupial bones, and by the higher development of the
-commissures of the brain. The _certain proof_ that Genuine Apes, and
-hence also our own race, are the direct descendants of Semi-apes, is to
-be found in the comparative anatomy and the ontogeny of Placental
-animals.
-
-
-NINETEENTH STAGE: +Tailed Apes (Menocerca)+.
-
-Of the two classes of Genuine Apes which developed out of the Semi-apes,
-it is only the narrow-nosed, or Catarrhini, which are closely related by
-blood to Man. Our older ancestors from this group probably resembled the
-still living Nose-apes and Holy-apes (Semnopithecus), which possess jaws
-and narrow noses like Man, but have a long tail, and their bodies
-densely covered with hair (p. 271). The Tailed Apes with narrow noses
-(Catarrhini Menocerci) _originated_ out of Semi-apes by the
-transformation of the jaw, and by the claws on their toes becoming
-changed into nails; this probably took place as early as the older
-Tertiary period. The _certain proof_ of our derivation from Tailed
-Catarrhini is to be found in the comparative anatomy and the ontogeny of
-Apes and of Man.
-
-
-TWENTIETH STAGE: +Man-like Apes (Anthropoides)+.
-
-Of all still living Apes the large tail-less, narrow-nosed Apes, namely,
-the Orang and Gibbon in Asia, the Gorilla and Chimpanzee in Africa, are
-most nearly akin to Man. It is probable that these Man-like Apes, or
-Anthropoides, originated during the Mid-tertiary period, namely, in the
-Miocene period. They developed out of the Tailed Catarrhini of the
-preceding stage--with which they essentially agree--by the loss of the
-tail, the partial loss of the hairy covering and by the excessive
-development of that portion of the brain just above the facial portion
-of the skull. There do not exist direct human ancestors among the
-Anthropoides of the present day, but they certainly existed among the
-unknown extinct Human Apes of the Miocene period. The _certain proof_ of
-their former existence is furnished by the comparative anatomy of
-Man-like Apes and of Man.
-
-
-TWENTY-FIRST STAGE: +Ape-like Men (Pithecanthropi)+.
-
-Although the preceding ancestral stage is already so nearly akin to
-genuine Men that we scarcely require to assume an intermediate
-connecting stage, still we can look upon the speechless Primæval Men
-(Alali) as this intermediate link. These Ape-like men, or
-Pithecanthropi, very probably existed towards the end of the Tertiary
-period. They originated out of the Man-like Apes, or Anthropoides, by
-becoming completely habituated to an upright walk, and by the
-corresponding stronger differentiation of both pairs of legs. The fore
-hand of the Anthropoides became the human hand, their hinder hand became
-a foot for walking. Although these Ape-like Men must not merely by the
-external formation of their bodies, but also by their internal mental
-development, have been much more akin to real Men than the Man-like Apes
-could have been, yet they did not possess the real and chief
-characteristic of man, namely, the articulate human language of words,
-the corresponding development of a higher consciousness, and the
-formation of ideas. The _certain proof_ that such Primæval Men without
-the power of speech, or Ape-like Men, must have preceded men possessing
-speech, is the result arrived at by an inquiring mind from comparative
-philology (from the "comparative anatomy" of language), and especially
-from the history of the development of language in every child ("glottal
-ontogenesis") as well as in every nation ("glottal phylogenesis").
-
-
-TWENTY-SECOND STAGE: +Men (Homines)+.
-
-Genuine Men _developed_ out of the Ape-like Men of the preceding stage
-by the gradual development of the animal language of sounds into a
-connected or articulate language, of words. The development of this
-function, of course, went hand in hand with the development of its
-organs, namely, the higher differentiation of the larynx and the brain.
-The transition from speechless Ape-like Men to Genuine or Talking Men
-probably took place at the beginning of the Quaternary period, namely,
-in the Diluvial period, but possibly even at an earlier date, in the
-more recent Tertiary. As, according to the unanimous opinion of most
-eminent philologists, all human languages are not derived from a common
-primæval language, we must assume a polyphyletic origin of language, and
-in accordance with this a polyphyletic transition from speechless
-Ape-like Men to Genuine Men.
-
-
-ANCESTRAL SERIES OF THE HUMAN PEDIGREE.
-
-M N = Boundary between the Invertebrate and Vertebrate Ancestors.
-
-
-  ---------------------------------------------------------------------------------------------------
-   _Epochs of the_ |  _Geological Periods_ |         _Animal_          |   _Nearest Living_
-      _Organic_    |       _of the_        |     _Ancestral Stages_    |  _Relatives of the_
-   _History of the_|   _Organic History_   |           _of_            |  _Ancestral Stages._
-       _Earth._    |    _of the Earth._    |          _Man._           |
-  ---------------------------------------------------------------------------------------------------
-                   {                       {  1. Monera                { _Protogenes_
-                   {                       {     (_Monera_)            { _Protamoeba_
-                   {                       {
-                   {                       {  2. Single-celled         { Simple Amoebæ
-                   {                       {     Primæval animals      { (_Automoebæ_)
-                   {                       {
-                   {                       {  3. Many-celled           { Communities of
-                   {                       {     Primæval animals      {   Amoebæ
-                   {                       {                           { (_Synamoebæ_)
-                   {                       {
-                   {                       {  4. Ciliated planulæ      { Planula larvæ
-                   {                       {     (_Planæada_)          {
-           I.      {                       {
-      ARCHILITHIC  { 1. Laurentian Period  {  5. Primæval Intestinal   { Gastrula larvæ
-          OR       {                       {     animals (_Gastræada_) {
-                   { 2. Cambrian Period    {
-      PRIMORDIAL   {                       {  6. Gliding Worms         { _Rhabdocoela_
-       EPOCH       { 3. Silurian Period    {     (_Turbellaria_)       { _Dendrocoela_
-                   {                       {
-                   {                       {  7. Soft-worms            { ?Between the Sea-squirts
-                   {                       {     (_Scolecida_)         {  and Gliding worms
-                   {                       {
-                   {                       {  8. Sack worms            { Sea-squirts
-                   {                       {     (_Himatega_)          { (_Ascidiæ_)
-                   {                       { M.................................................N
-                   {                       {  9. Skull-less            { Lancelets
-                   {                       {     (_Acrania_)           { (_Amphioxi_)
-                   {                       {
-                   {                       { 10. Single-nostriled      { Lampreys
-                   {                       {     (_Monorrhina_)        { (_Petromyzonta_)
-                   {  (Compare p. 22, and  {
-                   {  Plate XIV. and its   { 11. Primæval fish         { Sharks
-                   {  explanation.)        {     (_Selachii_)          { (_Squalacei_)
-  ---------------------------------------------------------------------------------------------------
-                   { 4. Devonian Period    { 12. Salamander fish       { Mud fish
-         II.       {                       {     (_Dipneusta_)         { (_Protopteri_)
-     PALÆOLITHIC   { 5. Coal Period        {
-         OR        {                       { 13. Gilled Amphibia       { (_Proteus_)
-                   { 6. Permian Period     {     (_Sozobranchia_)      { Axolotl (_Siredon_)
-       PRIMARY     {                       {
-        EPOCH      {                       { 14. Tailed Amphibia       { Water-newts
-                   {                       {     (_Sozura_)            { (_Tritons_)
-  ---------------------------------------------------------------------------------------------------
-                   {                       { 15. Primæval Amniota      { ?Between the Tailed-Amphibia
-        III.       {                       {     (_Protamnia_)         { and Primary
-     MESOLITHIC    { 7. Trias Period       {                           { mammals
-         OR        {                       {
-                   { 8. Jura Period        { 16. Primary Mammals       { Beaked animals
-      SECONDARY    {                       {     (_Promammalia_)       { (_Monotrema_)
-        EPOCH      { 9. Chalk Period       {
-                   {                       { 17. Pouched animals       { Pouched rats
-                   {                       {     (_Marsupialia_)       { (_Didelphys_)
-  ---------------------------------------------------------------------------------------------------
-                   {                       { 18. Semi-apes             { Lori (_Stenops_)
-                   {                       {     (_Prosimiæ_)          { Maki (_Lemur_)
-                   {                       {
-         IV.       {                       { 19. Tailed Narrow-nosed   { Nose apes
-     CENOLITHIC    { 10. Eocene Period     {     Apes                  { Holy apes
-         OR        {                       {
-                   { 11. Miocene Period    { 20. Men-like Apes or      { Gorilla, Chimpanzee,
-      TERTIARY     {                       { Tail-less Narrow-nosed    { Orang,
-       EPOCH       { 12. Pliocene Period   {   Apes                    { Gibbon
-                   {                       {
-                   {                       { 21. Speechless Men or     { Deaf and Dumb,
-                   {                       {     Ape-like Men          { Cretins or
-                   {                       {                           { Microcephali
-  ---------------------------------------------------------------------------------------------------
-         V.        {                       {                           {
-     QUATERNARY    { 13. Diluvial Period   { 22. Talking Men           { Australians and
-       EPOCH       { 14. Alluvial Period   {                           { Papuans
-
-
-
-
-CHAPTER XXIII.
-
-MIGRATION AND DISTRIBUTION OF MANKIND. HUMAN SPECIES AND HUMAN RACES.
-
-
-  Age of the Human Race.--Causes of its Origin.--The Origin of
-  Human Language.--Monophyletic or Single, Polyphyletic or
-  Multiple Origin of the Human Race.--Derivation of Man from many
-  Pairs.--Classification of the Human Races.--System of Twelve
-  Species of Men.--Woolly-haired Men, or Ulotrichis.--Bushy-haired
-  (Papuans, Hottentots).--Fleecy-haired (Caffres,
-  Negroes).--Straight-haired men, or Lissotrichi.--Stiff-haired
-  (Australians, Malays, Mongols, Arctic, and American
-  Tribes).--Curly-haired (Dravidas, Nubians, Midlanders).--Number
-  of Population.--Primæval Home of Man (South Asia, or
-  Lemuria).--Nature of Primæval Men.--Number of Primæval Languages
-  (Monoglottists and Polyglottists).--Divergence and Migration of
-  the Human Race.--Geographical Distribution of the Human Species.
-
-
-The rich treasure of knowledge we possess in the comparative anatomy and
-the history of the development of Vertebrate animals, enables us even
-now to establish the most important outlines of the human pedigree in
-the way we have done in the last chapter. One must, however, not expect
-to be able to survey satisfactorily in every detail the history or
-phylogeny of the human species which will henceforth form the basis of
-Anthropology, and of all other sciences. The complete development of
-this most important science--of which we can only lay the first
-foundation--must remain reserved for the more accurate and extensive
-investigations of a future time. This applies also to those more special
-questions of human phylogeny at which it is desirable before concluding
-to take a cursory glance, namely, the question of the time and place of
-the origin of the human race, as also of the different species and races
-into which it has differentiated.
-
-In the first place, the period of the earth's history, within which the
-slow and gradual transmutation of the most man-like apes into the most
-ape-like men took place, can of course not be determined by years, nor
-even by centuries. This much can, however, with full assurance be
-maintained, for reasons given in the last chapter, that Man is derived
-from Placental animals. Now, as fossil remains of these Placentalia are
-found only in the tertiary rocks, the human race can at the earliest
-have developed only within the Tertiary period out of perfected man-like
-apes. What seems most probable is that this most important process in
-the history of terrestrial creation occurred towards the end of the
-Tertiary period, that is in the Pliocene, perhaps even in the Miocene
-period, but possibly also not until the beginning of the Diluvial
-period. At all events Man, as such, lived in central Europe as early as
-the Diluvial period, contemporaneously with many large, long since
-extinct mammals, especially with the diluvial elephant, or mammoth
-(Elephas primigenius), the woolly-haired rhinoceros (Rhinoceros
-tichorrhinus), the giant deer (Cervus euryceros), the cave bear (Ursus
-spelæus), the cave hyæna (Hyæna spelæa), the cave lion (Felis spelæus),
-etc. The results brought to light by recent geology and archæology as to
-these fossil men and their animal contemporaries of the diluvial period,
-are of the greatest interest. But as a closer examination of them would
-occupy too much of my limited space, I must confine myself here to
-setting forth their great general importance, and refer for particulars
-to the numerous writings which have recently been published on the
-Primæval History of Man, more especially to the excellent works of
-Charles Lyell,(30) Carl Vogt,(27) Friedrich Rolle,(28) John Lubbock,(44)
-L. Büchner,(43) etc.
-
-The numerous and interesting discoveries presented to us by these
-extensive investigations of late years on the primæval history of the
-human race, place the important fact (long since probable for many other
-reasons) beyond a doubt, that the human race, as such, has existed for
-more than twenty thousand years. But it is also probable that more than
-a hundred thousand years, perhaps many hundred thousands of years, have
-elapsed since its first appearance; and, in contrast to this, it must
-seem very absurd that our calendars still represent the "Creation of the
-World, according to Calvisius," to have taken place 5821 years ago.
-
-Now, whether we reckon the period during which the human race, as such,
-has existed and diffused itself over the earth, as twenty thousand, a
-hundred thousand, or many hundred thousands of years, the lapse of time
-is in any case immensely small in comparison with the inconceivable
-length of time which was requisite for the gradual development of the
-long chain of human ancestors. This is evident even from the small
-thickness of all Diluvial deposits in comparison with the Tertiary, and
-of these again in comparison with the preceding deposits. (Compare p.
-22.) But the infinitely long series of slowly and gradually developing
-animal forms from the simplest Moneron to the Amphioxus, from this to
-the Primæval Fish, from the Primæval Fish to the first Mammal, and
-again, from the latter to Man, also require for their historical
-development a succession of periods probably comprising many thousands
-of millions of years. (Compare vol. i. p. 129.)
-
-Those processes of development which led to the origin of the most
-Ape-like Men out of the most Man-like Apes must be looked for in the two
-adaptational changes which, above all others, are distinctive of Man,
-namely, _upright walk_ and _articulate speech_. These two
-_physiological_ functions necessarily originated together with two
-corresponding _morphological_ transmutations, with which they stand in
-the closest correlation, namely, the _differentiation of the two pairs
-of limbs and the differentiation of the larynx_. The important
-perfecting of these organs and their functions must have necessarily and
-powerfully reacted upon the differentiation of the brain and the mental
-activities dependent upon it, and thus have paved the way for the
-endless career in which Man has since progressively developed, and in
-which he has far outstripped his animal ancestors. (Gen. Morph. ii. p.
-430.)
-
-The first and earliest of these three great processes in the development
-of the human organism probably was the _higher differentiation and the
-perfecting of the extremities_ which was effected by the _habit of an
-upright walk_. By the fore feet more and more exclusively adopting and
-retaining the function of grasping and handling, and the hinder feet
-more and more exclusively the function of standing and walking, there
-was developed that contrast between the hand and foot which is indeed
-not exclusively characteristic of man, but which is much more strongly
-developed in him than in the apes most like men. This differentiation of
-the fore and hinder extremities was, however, not merely most
-advantageous for their own development and perfecting, but it was
-followed at the same time by a whole series of very important changes in
-other parts of the body. The whole vertebral column, and more especially
-the girdle of the pelvis and shoulders, as also the muscles belonging to
-them, thereby experienced those changes which distinguish the human body
-from that of the most man-like apes. These transmutations were probably
-accomplished long before the origin of articulate speech; and the human
-race thus existed for long, with an upright walk and the characteristic
-human form of body connected with it, before the actual development of
-human language, which would have completed the second and the more
-important part of human development. We may therefore distinguish a
-special (21st) stage in the series of our human ancestors, namely,
-Speechless Man (Alalus), or Ape-man (Pithecanthropus), whose body was
-indeed formed exactly like that of Man in all essential characteristics,
-but who did not as yet possess articulate speech.
-
-The origin of _articulate language_, and the _higher differentiation and
-perfecting of the larynx_ connected with it, must be looked upon as only
-a later, and the most important stage in the process of the development
-of Man. It was, doubtless, this process which above all others helped to
-create the deep chasm between man and animal, and which also first
-caused the most important progress in the mental activity and the
-perfecting of the brain connected with it. There indeed exists in very
-many animals a language for communicating sensations, desires, and
-thoughts, partly a language of gestures, partly a language of feeling or
-touch, partly a language of cries or sounds, but a real language of
-words or ideas, a so-called "articulate" language, which by abstraction
-changes sounds into words, and words into sentences, belongs, as far as
-we know, exclusively to Man.
-
-The origin of human language must, more than anything else, have had an
-ennobling and transforming influence upon the mental life of Man, and
-consequently upon his brain. The higher differentiation and perfecting
-of the brain and mental life as its highest function developed in direct
-correlation with its expression by means of speech. Hence, the highest
-authorities in comparative philology justly see in the development of
-human speech the most important process which distinguishes Man from his
-animal ancestors. This has been especially set forth by August
-Schleicher, in his treatise "On the Importance of Speech for the Natural
-History of Man."(34) In this relation we see one of the closest
-connections between comparative zoology and comparative philology; and
-here the theory of development assigns to the latter the task of
-following the origin of language step by step. This task, as interesting
-as it is important, has of late years been successfully undertaken by
-many inquirers, but more especially by Wilhelm Bleek, who has been
-occupied for seventeen years in South Africa with the study of the
-languages of the lowest races of men, and hence has been enabled to
-solve the question. August Schleicher more especially discusses, in
-accordance with the theory of selection, how the various forms of
-speech, like all other organic forms and functions, have developed by
-the process of natural selection, and have divided into many species and
-dialects.
-
-I have no space here to follow the process of the formation of language,
-and must refer in regard to this to the above-mentioned important work
-of Wilhelm Bleek, "On the Origin of Language."(35) But we have still to
-mention one of the most important results of comparative philology,
-which is of the highest importance to the genealogy of the human
-species, that is, that _human language was probably of a multiple, or
-polyphyletic origin_. Human speech, as such, did not develop probably
-until the genus of Speechless or Primæval Man, or Ape Man, had
-separated into several kinds or species. In each of these human species,
-and perhaps even in the different sub-species and varieties of this
-species, language developed freely and independently of the others. At
-least Schleicher, one of the first authorities on the subject, maintains
-that "even the beginnings of language--in sounds as well as in regard to
-ideas and views which were reflected in sounds, and further, in regard
-to their capability of development--must have been different. For it is
-positively impossible to trace all languages to one and the same
-primæval language. An impartial investigation rather shows that there
-are as many primæval languages as there are races."(34) In like manner,
-Friederich Müller(41) and other eminent linguists assume a free and
-independent origin of the families of languages and their primæval
-stocks. It is well known, however, that the boundaries of these tribes
-of languages and their ramifications are by no means always the
-boundaries of the different human species, or the so-called "races,"
-distinguished by us on account of their bodily characteristics. This,
-as well as the complicated relations of the mixture of races, and the
-various forms of hybrids, is the great difficulty lying in the way of
-tracing the human pedigree in its individual branches, species, races,
-varieties, etc.
-
-In spite of these great and serious difficulties, we cannot here refrain
-from taking one more cursory glance at the ramification of the human
-pedigree, and at the same time considering, from the point of view of
-the theory of descent, the much discussed question of the monophyletic
-or polyphyletic origin of the human race, and its species or races. As
-is well known, two great parties have for a long time been at war with
-each other upon this question; the _monophylists_ (or monogenists)
-maintain the unity of origin and the blood relationship of all races of
-men. The _polyphylists_ (or polygenists), on the other hand, are of
-opinion that the different races of men are of independent origin.
-According to our previous genealogical investigations we cannot doubt
-that, at least in a _wide sense_, the monophyletic opinion is the right
-one. For even supposing that the transmutation of Man-like Apes into Men
-had taken place several times, yet those Apes themselves would again be
-allied by the one pedigree common to the whole order of Apes. The
-question therefore would always be merely about a nearer or remoter
-degree of blood relationship. In a _narrower sense_, on the other hand,
-the polyphylist's opinion would probably be right, inasmuch as the
-different primæval languages have developed quite independently of one
-another. Hence, if the origin of an articulate language is considered as
-the real and principal act of humanification, and the species of the
-human race are distinguished according to the roots of their language,
-it might be said that the different races of men had originated,
-independently of one another, by different branches of primæval,
-speechless men directly springing from apes, and forming their own
-primæval language. Still they would of course be connected further up or
-lower down at their root, and thus all would finally be derived from a
-common primæval stock.
-
-While we hold the latter of these convictions, and while we for many
-reasons believe that the different species of speechless primæval men
-were all derived from a common ape-like human form, we do not of course
-mean to say that _all men are descended from one pair_. This latter
-supposition, which our modern Indo-Germanic culture has taken from the
-Semitic myth of the Mosaic history of creation, is by no means tenable.
-The whole of the celebrated dispute, as to whether the human race is
-descended from a single pair or not, rests upon a completely false way
-of putting the question. It is just as senseless as the dispute as to
-whether all sporting dogs or all race-horses are descended from a single
-pair. We might with equal justice ask whether all Germans or all
-Englishmen are "descended from a single pair," etc. A "first human
-pair," or "a first man," has in fact never existed, any more than there
-ever existed a first pair or a first individual of Englishmen, Germans,
-race-horses, or sporting dogs. The origin of a new species, of course,
-always results from an existing species, by a long chain of many
-different individuals sharing the slow process of transformation.
-Supposing that we had all the different pairs of Human Apes and Ape-like
-Men before us--which belong to the true ancestors of the human race--it
-would even then be quite impossible (without doing so most arbitrarily)
-to call any one of these pairs of ape-like men "the first pair." As
-little can we derive each of the twelve races or species of men, which
-we shall consider directly, from a "first pair."
-
-The difficulties met with in classifying the different races or species
-of men are quite the same as those which we discover in classifying
-animal and vegetable species. In both cases forms apparently quite
-different are connected with one another by a chain of intermediate
-forms of transition. In both cases the dispute as to what is a kind or a
-species, what a race or a variety, can never be determined. Since
-Blumenbach's time, as is well known, it has been thought that mankind
-may be divided into five races or varieties, namely: (1) the Ethiopian,
-or black race (African negro); (2) the Malayan, or brown race (Malays,
-Polynesians, and Australians); (3) the Mongolian, or yellow race (the
-principal inhabitants of Asia and the Esquimaux of North America); (4)
-the Americans, or red race (the aborigines of America); and (5) the
-Caucasian, or white race (Europeans, north Africans, and south-western
-Asiatics). All of these five races of men, according to the Jewish
-legend of creation, are said to have been descended from "a single
-pair"--Adam and Eve,--and in accordance with this are said to be
-varieties of one kind or species. If, however, we compare them without
-prejudice, there can be no doubt that the differences of these five
-races are as great and even greater than the "specific differences" by
-which zoologists and botanists distinguish recognised "good" animal and
-vegetable species ("bonæ species"). The excellent palæontologist
-Quenstedt is right in maintaining that, "if Negroes and Caucasians were
-snails, zoologists would universally agree that they represented two
-very excellent species, which could never have originated from one pair
-by gradual divergence."
-
-The characteristics by which the races of men are gradually
-distinguished are partly taken from the formation of the hair, partly
-from the colour of the skin, and partly from the formation of the skull.
-In regard to the last character, two extremes are distinguished, namely,
-long heads and short heads. In _long-headed men_ (Dolichocephali), whose
-strongest development is found in Negroes and Australians, the skull is
-extended, narrow, and compressed on the right and left. In _short-headed
-men_ (Brachycephali), on the other hand, the skull is compressed in an
-exactly opposite manner, from the front to the back, is short and broad,
-which is especially striking in the case of the Mongolians.
-_Medium-headed men_ (Mesocephali), standing between the two extremes,
-predominate especially among Americans. In every one of these three
-groups we find men with _slanting teeth_ (Prognathi), whose jaws, like
-those of the animal snout, strongly project, and whose front teeth
-therefore slope in front, and men with _straight teeth_ (Orthognathi),
-whose jaws project but little, and whose front teeth stand
-perpendicularly. During the last ten years a great deal of time and
-trouble have been devoted to the careful examination and measurement of
-the forms of skulls, which have, however, not been rewarded by
-corresponding results. For within a single species, as for example
-within the Mediterranean species, the form of the skull may vary so much
-that both extremes are met with in the same species. Much better
-starting-points for the classification of the human species are
-furnished by the nature of the hair and speech, because they are much
-more strictly hereditary than the form of the skull.
-
-Comparative philology seems especially to be becoming an authority in
-this matter. In the latest great work on the races of men, which
-Friederich Müller has published in his excellent "Ethnography,"(42) he
-justly places language in the fore-ground. Next to it the nature of the
-hair of the head is of great importance; for although it is in itself of
-course only a subordinate morphological character, yet it seems to be
-strictly transmitted within the race. Of the twelve species of men
-distinguished on the following table (p. 308), the four lower species
-are characterised by the woolly nature of the hair of their heads; every
-hair is flattened like a tape, and thus its section is oval. These four
-species of _woolly-haired men_ (Ulotrichi) we may reduce into two
-groups--tuft-haired and fleecy-haired. The hair on the head of
-_tuft-haired men_ (Lophocomi), Papuans and Hottentots, grows in
-unequally divided small tufts. The woolly hair of _fleecy-haired men_
-(Eriocomi), on the other hand, in Caffres and Negroes, grows equally all
-over the skin of the head. All Ulotrichi, or woolly-haired men, have
-slanting teeth and long heads, and the colour of their skin, hair, and
-eyes is always very dark. All are inhabitants of the Southern
-Hemisphere; it is only in Africa that they come north of the equator.
-They are on the whole at a much lower stage of development, and more
-like apes, than most of the Lissotrichi, or straight-haired men. The
-Ulotrichi are incapable of a true inner culture and of a higher mental
-development, even under the favourable conditions of adaptation now
-offered to them in the United States of North America. No woolly-haired
-nation has ever had an important "history."
-
-
-SYSTEMATIC SURVEY
-
-_Of the 12 Species of Men and their 36 Races._
-
-(Compare Plate XV.)
-
-
-  -------------------+--------------------------+----------------------------+-------------
-     _Species._      |         _Races._         |         _Home._            | _Immigrated_
-                     |                          |                            |  _from the_
-  -------------------+--------------------------+----------------------------+-------------
-  { 1. =Papuan=      {  1. Nigritos               Malacca, Philippine          West
-  { +Homo Papua+     {                              Islands
-  {                  {  2. New Guinea men         New Guinea                   West
-  { 2. =Hottentot=   {  3. Melanesians            Melanesia                    North-west
-  {     +Homo+       {  4. Tasmanians             Van Diemen's Land            North-east
-  { +Hottentottus+
-  {                  {  5. Hottentots             The Cape                     North-east
-  {                  {  6. Bushmen                The Cape                     North-east
-
-  { 3. =Kaffre=      {  7. Zulu Kaffres           Eastern South Africa         North
-  { +Homo Cafer+     {  8. Beschuanas             Central South Africa         North-east
-  {                  {  9. Congo Kaffres          Western South Africa         East
-  {
-  { 4. =Negro=       { 10. Tibu negroes           Tibu district                South-east
-  { +Homo Niger+     { 11. Soudan negroes         Soudan                       East
-  {                  { 12. Senegambians           Senegambia                   East
-  {                  { 13. Nigritians             Nigritia                     East
-  .......................................................................................
-
-  { 5. =Australian=  { 14. North Australians      North Australia              North
-  { +H. Australis+   { 15. South Australians      South Australia              North
-  {
-  { 6. =Malay=       { 16. Sundanesians           Sunda Archipelago            West
-  { +Homo Malayus+   { 17. Polynesians            Pacific Archipelago          West
-  {                  { 18. Natives of Madagascar  Madagascar                   East
-  {
-  { 7. =Mongolian=   { 19. Indo-Chinese           Tibet, China                 South
-  {    +Homo+        { 20. Coreo-Japanese         Corea, Japan                 South-west
-  {  +Mongolus+      { 21. Altaians }             Central Asia, North Asia     South
-  {                  { 22. Uralians}              North-western Asia,          South-east
-  {                  {                              Northern Europe,
-  {                  {                              Hungary
-  {
-  { 8. =Arctic Men=  { 23. Hyperboreans           Extreme N.E. of Asia         South-west
-  { +Homo Arcticus+  { 24. Esquimaux              The extreme north of         West
-  {                  {                             America
-  {
-  { 9. =American=    { 25. North Americans        North America                North-west
-  {    +Homo+        { 26. Central Americans      Central America              North
-  { +Americanus+     { 27. South Americans        South America                North
-  {                  { 28. Patagonians            The extreme south of         North
-  {                  {                              South America
-
-  { 10. =Dravidas=   { 29. Deccans                Hindostan                    East?
-  { +Homo Dravida+   { 30. Singalese              Ceylon                       North?
-  {
-  { 11. =Nubian=     { 31. Dongolese              Nubia                        East
-  { +Homo Nuba+      { 32. Fulatians              Fulu-land (Central           East
-  {                  {                              Africa)
-  {
-  { 12.              { 33. Caucasians             Caucasus                     South-east
-  { =Mediterranese=  { 34. Basque                 Extreme north of Spain       South?
-  {    +Homo+        { 35. Semites                Arabia, North Africa, etc.   East
-  { +Mediterraneus+  { 36. Indo-germanic          South-western Asia,          South-east
-  {                  {       tribes                 Europe, etc.
-
-             ----------------------------------------------------------------
-
-                                                          Indo-Germanians
-   9. =Americans=                               Semites          |
-       |                        Magyars            |             |    Caucasians
-       |   Esquimaux               |               |    Basques  |         |
-       |        |                 Fins             |       |     |         |
-       |        |                  |               \---v---/     \----v----/
-       |  Hyperboreans             |                   |              |
-       | 8. =Arctic Men=           |    Samoides       |              |
-       |        |          Tartars |       |           |              |
-       |        |             |    |       |           \-------v-------/
-       \---v----/             |    |       |          12. =Mediterranese=
-           |        Calmucks  |    |       |      Singalese    |
-           | Tungusians |     |    |       |          |        |   Fulatians
-           |      |     |     |    |       |       Deccans     |       |
-           \--------v---------/    \---v---/    10. =Dravidas= |   Dongolese
-                 =Altaians=        =Uralians=         |        | 11. =Nubians=
-                    |                  |              |        |       |
-                    |                  |              |        |       |
-  Japanese          \--------v---------/              \-------v--------/
-      |               =Ural-Altaians=                     +Euplocomi+
-      |         Chinese          |                              |
-  Coreans          |     Siamese |               Madagascars    |
-      |            | Tibet  |    |  Polynesians       |         |
-      |            |   |    |    |        |           |         |        4. =Negroes=
-      |            |   |    |    |        |           |         | 3. =Kaffres=   |
-  =Coreo-Japanese= \---v----/    |        \-----v-----/         |      |         |
-      |          =Indo-Chinese=  |         Sundanesians         |      |         |
-      |               |          |              |               |      \---v-----/
-      |               |          |              |               |       +Eriocomi+
-      |               |          |              |               |          |
-      \-----------v-------------/         6. =Malays=           |          |
-             7. =Mongols=                       |               |          |
-                  |                             |               |          |
-                  |                             |               |          |
-                  \-------v-------------------------------------/          |
-                      =Promalays=                  2. =Hottentots=         |
-                          |               1. =Papuans=     |               |
-                          |   5. =Australians=    |        |               |
-                          |           |           |        |               |
-                          |           |           \----v---/               |
-                          \-----v-----/          +Lophocomi+               |
-                            +Euthycomi+                |                   |
-                                |                      \---------v---------/
-                                |                         =Woolly-haired=
-                         =Straight-haired=                   +Ulotrichi+
-                           +Lissotrichi+                         |
-                                |                                |
-                                |                                |
-                                \--------------v-----------------/
-                                         +Primæval Men+
-
-
-In the eight higher races of men, which we comprise as _straight-haired_
-(Lissotrichi), the hair of the head is never actually woolly, although
-it is very much frizzled in some individuals. Every separate hair is
-cylindrical (not like a tape), and hence its section is circular (not
-oval).
-
-The eight races of Lissotrichi may likewise be divided into two
-groups--stiff-haired and curly-haired. _Stiff-haired men_ (Euthycomi),
-the hair of whose heads is quite smooth and straight, and not frizzled,
-include Australians, Malays, Mongolians, Arctic tribes, and Americans.
-Curly-haired men, on the other hand, the hair of whose heads is more or
-less curly, and in whom the beard is more developed than in all other
-species, include the Dravidas, Nubians, and Mediterranean races.
-(Compare Plate XV.)
-
-Now, before we venture upon the attempt hypothetically to explain the
-phyletic divergence of mankind, and the genealogical connection of its
-different species, we will premise a short description of the twelve
-named species and of their distribution. In order clearly to survey
-their geographical distribution, we must go back some three or four
-centuries, to the time when the Indian Islands and America were first
-discovered, and when the present great mingling of species, and more
-especially the influx of the Indo-Germanic race, had as yet not made
-great progress. We begin with the lowest stages, with the woolly-haired
-men (Ulotrichi), all of whom are prognathic Dolichocephali.
-
-The _Papuan_ (Homo Papua), of all the still living human species, is
-perhaps most closely related to the original primary form of
-woolly-haired men. This species now inhabits only the large island of
-New Guinea and the Archipelago of Melanesia lying to the east of it
-(Solomon's Islands, New Caledonia, the New Hebrides, etc.). But
-scattered remnants of it are also still found in the interior of the
-peninsula of Malacca, and likewise in many other islands of the large
-Pacific Archipelago; mostly in the inaccessible mountainous parts of the
-interior, and especially in the Philippine Islands. The but lately
-extinct Tasmanians, or the natives of Van Diemen's Land, belonged to
-this group. From these and other circumstances it is clear that the
-Papuans in former times possessed a much larger area of distribution in
-south-eastern Asia. They were driven out by the Malays and forced
-eastwards. The skin of all Papuans is of a black colour, sometimes more
-inclining to brown, sometimes more to blue. Their woolly hair grows in
-tufts, is spirally twisted in screws, and often more than a foot in
-length, so that it forms a strong woolly wig, which stands far out from
-the head. Their face, below the narrow depressed forehead, has a large
-turned-up nose and thick protruding lips. The peculiar form of their
-hair and speech so essentially distinguishes the Papuans from their
-straight-haired neighbours, from the Malays as well as from the
-Australians, that they must be regarded as an entirely distinct species.
-
-Closely related to the Papuans by the tufted growth of hair, but
-geographically widely separated from them, are the _Hottentots_ (Homo
-Hottentottus). They inhabit exclusively the southernmost part of Africa,
-the Cape and the adjacent parts, and have immigrated there from the
-north-east. The Hottentots, like their original kinsmen the Papuans,
-occupied in former times a much larger area (probably the whole of
-Eastern Africa), and are now approaching their extinction. Besides the
-genuine Hottentots--of whom there now exist only the two tribes of the
-Coraca (in the eastern Cape districts) and the Namaca (in the western
-portion of the Cape)--this species also includes the Bushmen (in the
-mountainous interior of the Cape). The woolly hair of all Hottentots
-grows in tufts, like brushes, as in the case of Papuans. Both species
-also agree in the posterior part of the body, in the female sex being
-specially inclined to form a great accumulation of fat (Steatopygia).
-But the skin of Hottentots is much lighter, of a yellowish brown colour.
-Their very flat face is remarkable for its small forehead and nose, and
-large nostrils. The mouth is very broad with big lips, the chin small
-and pointed. Their speech is characterised by several quite peculiar
-guttural sounds.
-
-The next neighbours and kinsmen of Hottentots are _Kaffres_ (Homo
-Cafer). This woolly-haired human species is, however, distinguished,
-like the following one (the genuine Negro), from Hottentots and Papuans
-by the woolly hair not being divided into tufts, but covering the head
-as a thick fleece. The colour of their skin varies through all shades,
-from the yellowish black of the Hottentot to the brown black or pure
-black of the genuine Negro. While in former times the race of Kaffres
-was assigned to a very small area of distribution, and was generally
-looked upon only as a variety of the genuine Negro, this species is now
-considered to include almost the whole of the inhabitants of equatorial
-Africa, from the 20th degree south latitude to the 4th degree north;
-consequently, all South Africans, with the exception of the Hottentots.
-They include especially the inhabitants of the Zulu, Zambesi, and
-Mozambique districts on the east coast, the large human families of the
-Beschuans or Setschuans in the interior, and the Herrero and Congo
-tribes of the west coast. They too, like the Hottentots, have immigrated
-from the north-east. Kaffres, who were usually classed with Negroes,
-differ very essentially from them by the formation of their skull and by
-their speech. Their face is long and narrow, their forehead high, and
-their nose prominent and frequently curved, their lips not so
-protruding, and their chin pointed. The many languages of the different
-tribes of Kaffres can all be derived from an extinct primæval language,
-namely, from the Bantu language.
-
-The genuine _Negro_ (Homo Niger)--when Kaffres, Hottentots, and Nubians
-are separated from him--at present forms a much less comprehensive human
-species than was formerly supposed. They now only include the Tibus, in
-the eastern parts of the Sahara; the Sudan people, or Sudians, who
-inhabit the south of that large desert; also the inhabitants of the
-Western Coast of Africa, from the mouth of the Senegal in the north, to
-beyond the estuary of the Niger in the south (Senegambians and
-Nigritians). Genuine Negroes are accordingly confined between the
-equator and the Tropic of Capricorn, and only a small portion of the
-Tibu tribe in the east have gone beyond this boundary. The Negro species
-has spread within this zone, coming from the east. The colour of the
-skin of genuine negroes is always more or less of a pure black. Their
-skin is velvety to the touch, and characterised by a peculiar offensive
-exhalation. Although Negroes agree with Kaffres in the formation of the
-woolly hair of the head, yet they differ essentially in the formation of
-their face. Their forehead is flatter and lower, their nose broad and
-thick, not prominent, their lips large and protruding, and their chin
-very short. Genuine Negroes are moreover distinguished by very thin
-calves and very long arms. This species of men must have branched into
-many separate tribes at a very early period, for their numerous and
-entirely distinct languages can in no way be traced to one primæval
-language.
-
-To the four woolly-haired species of men just discussed, straight-haired
-men (Homines Lissotrichi) stand in strong contrast, as another main
-branch of the genus. Five of the eight species of the latter, as we have
-seen, can be comprised as stiff-haired (Euthycomi) and three as
-curly-haired (Euplocomi). We shall in the first place consider the
-former, which includes the primæval inhabitants of the greater part of
-Asia and the whole of America.
-
-The lowest stage of all straight-haired men, and on the whole perhaps of
-all the still living human species, is occupied by the _Australian_, or
-_Austral-negro_ (Homo Australis). This species seems to be exclusively
-confined to the large island of Australia; it resembles the genuine
-African Negro by its black or brownish black hair, and the offensive
-smell of the skin, by its very slanting teeth and long-headed form of
-skull, the receding forehead, broad nose, protruding lips, and also by
-the entire absence of calves. On the other hand Australians differ from
-genuine Negroes as well as from their nearest neighbours the Papuans, by
-the much weaker and more delicate structure of their bones, and more
-especially by the formation of the hair of their heads, which is not
-woolly and frizzled, but either quite lank or only slightly curled. The
-very low stage of bodily and mental development of the Australian is
-perhaps not altogether original, but has arisen by degeneration, that
-is, by adaptation to the very unfavourable conditions of existence in
-Australia. They probably immigrated to their present home from the north
-or north-west, as a very early offshoot of the Euthycomi. They are
-probably more closely related to the Dravidas, and hence to the
-Euplocomi, than the other Euthycomi. The very peculiar language of the
-Australians is broken up into numerous small branches, which are grouped
-into a northern and a southern class.
-
-The _Malay_ (Homo Malayus), the brown race of ethnographers, although
-not a large species, is important in regard to its genealogy. An extinct
-south Asiatic human species, very closely related to the Malays of the
-present day, must probably be looked upon as the common primary form of
-this and the following higher human species. We will call this
-hypothetical primary species, Primæval Malays, or Promalays. The Malays
-of the present day are divided into two widely dispersed races, the
-_Sundanesians_, who inhabit Malacca, the Sunda Islands (Sumatra, Java,
-Borneo, etc.) and the Philippine Islands, and the _Polynesians_, who are
-dispersed over the greater portion of the Pacific Archipelago. The
-northern boundary of their wide tract of distribution is formed on the
-east by the Sandwich Islands (Hawai), and on the west by the Marian
-Islands (Ladrones); the southern boundary on the east is formed by the
-Mangareva Archipelago, and on the west by New Zealand. The inhabitants
-of Madagascar are an especial branch of Sundanesians who have been
-driven to the far west. This wide pelagic distribution of the Malays is
-explained by their partiality for nautical life. Their primæval home is
-the south-eastern portion of the Asiatic continent, from whence they
-spread to the east and south, and drove the Papuans before them. The
-Malays, in the formation of body, are nearest akin to the Mongols, but
-are also nearly allied to the curly-haired Mediterranese. They are
-generally short-headed, more rarely medium-headed, and very rarely
-long-headed. Their hair is black and stiff, but frequently somewhat
-curled. The colour of their skin is brown, sometimes yellowish, or of a
-cinnamon colour, sometimes reddish or copper brown, more rarely dark
-brown. In regard to the formation of face, Malays in a great measure
-form an intermediate stage between the Mongols and the Mediterranese;
-they can frequently not be distinguished from the latter. Their face is
-generally broad, with prominent nose and thick lips, the opening for
-their eyes not so narrowly cut and slanting as in Mongols. The near
-relationship between all Malays and Polynesians is proved by their
-language, which indeed broke up at an early period into many small
-branches, but still can always be traced to a common and quite peculiar
-primæval language.
-
-The _Mongol_ (Homo Mongolus) is, next to the Mediterranese, the richest
-in individuals. Among them are all the inhabitants of the Asiatic
-Continent, excepting the Hyperboreans in the north, the few Malays in
-the south-east (Malacca), the Dravidas in Western India, and the
-Mediterranese in the south-west. In Europe this species of men is
-represented by the Fins and Lapps in the north, by the Osmanlis in
-Turkey, and the Magyars in Hungary. The colour of the Mongol is always
-distinguished by a yellow tone, sometimes a light pea green, or even
-white, sometimes a darker brownish yellow. Their hair is always stiff
-and black. The form of their skull is, in the great majority of cases,
-decidedly short (especially in Kalmucks, Baschkirs, etc.) but frequently
-of medium length (Tartars, Chinese, etc.) But among them we never meet
-with genuine long-headed men. The narrow openings of their eyes, which
-are generally slanting, their prominent cheek bones, broad noses, and
-thick lips are very striking, as well as the round form of their faces.
-The language of the Mongols is probably traceable to a common primæval
-language; but the monosyllabic languages of the Indo-Chinese races, and
-the polysyllabic languages of the other Mongol races, stand in contrast
-as two main branches which separated at an early time. The monosyllabic
-tribes of the Indo-Chinese include the Tibetans, Birmans, Siamese, and
-Chinese. The other polysyllabic Mongols are divided into three races,
-namely: (1) the Coreo-Japanese (Coreans and Japanese); (2) the Altaians
-(Tartars, Kirgises, Kalmucks, Buriats, Tungusians); and (3) the Uralians
-(Samoiedes, Fins). The Magyars of Hungary are descended from the Fins.
-
-The _Polar men_ (Homo Arcticus) must be looked upon as a branch of the
-Mongolian human species. We comprise under this name the inhabitants of
-the Arctic Polar lands of both hemispheres, the Esquimaux (and
-Greenlanders) in North America, and the Hyperboreans in north-eastern
-Asia (Jukagirs, Tschuksches, Kuriaks, and Kamtschads). By adaptation to
-the Polar climate, this human race has become so peculiarly transformed
-that it may be considered as a distinct species. Their stature is low
-and of a square build; the formation of their skull of medium size or
-even long; their eyes narrow and slanting like the Mongols; their
-cheek-bones prominent, and their mouth wide. Their hair is stiff and
-black; the colour of their skin is of a light or dark brown tinge,
-sometimes more inclined to white or to yellow, like that of the Mongols,
-sometimes more to red, like that of the Americans. The languages of
-Polar men are as yet little known, but they differ both from the
-Mongolian and from the American. Polar men must probably be regarded as
-a remnant and a peculiarly adapted branch of that tribe of Mongols which
-emigrated from north-eastern Asia to North America, and populated that
-part of the earth.
-
-At the time of the discovery of America, that part of the earth was
-peopled (setting aside the Esquimaux) only by a single human species,
-namely, by the _Redskins_, or _Americans_ (Homo Americanus). Of all
-other human species they are most closely related to the two preceding.
-The form of their skull is generally a medium one, rarely short or
-long-headed. Their forehead broad and very low; their nose large,
-prominent, and frequently aquiline; their cheek-bones prominent; their
-lips rather thin than thick. The colour of their skin is characterised
-by a red fundamental tint, which is, however, sometimes pure copper-red,
-or light red, sometimes a deeper reddish brown, yellow brown or olive
-brown. The numerous languages of the various American races and tribes
-are extremely different, yet they agree in their original foundation.
-Probably America was first peopled from north-eastern Asia by the same
-tribe of Mongols from whom the Polar men (Hyperboreans and Esquimaux)
-have also branched. This tribe first spread in North America, and from
-thence migrated over the isthmus of Central America down to South
-America, at the extreme south of which the species degenerated very
-much by adaptation to the very unfavourable conditions of existence. But
-it is also possible that Mongols and Polynesians immigrated from the
-west and mixed with the former tribe. In any case the aborigines of
-America came over from the Old World, and did not, as some suppose, in
-any way originate out of American apes. Catarrhini, or Narrow-nosed
-Apes, never at any period existed in America.
-
-The three human species still to be considered--the Dravidas, Nubians,
-and Mediterranese--agree in several characteristics which seem to
-establish a close relationship between them, and distinguish them from
-the preceding species. The chief of these characteristics is the strong
-development of the beard, which in all other species is either entirely
-wanting or but very scanty. The hair of their heads is generally not so
-lank and smooth as in the five preceding species, but in most cases more
-or less curly. Other characteristics also seem to favour our classing
-them in one main group of curly-haired men (Euplocomi).
-
-The _Dravida man_ (Homo Dravida) seems to stand very near the common
-primary form of the Euplocomi, and perhaps of Lissotrichi. At present
-this primæval species is only represented by the Deccan tribes in the
-southern part of Hindostan, and by the neighbouring inhabitants of the
-mountains on the north-east of Ceylon. But in earlier times this race
-seems to have occupied the whole of Hindostan, and to have spread even
-further. It shows, on the one hand, traits of relationship to the
-Australians and Malays; on the other, to the Mongols and Mediterranese.
-Their skin is either of a light or dark brown colour; in some tribes, of
-a yellowish brown, in others, almost black brown. The hair of their
-heads, as in Mediterranese, is more or less curled, neither quite
-smooth, like that of the Euthycomi, nor actually woolly, like that of
-the Ulotrichi. The strong development of the beard is also like that of
-the Mediterranese. The oval form of face seems partly to be akin to that
-of the Malays, partly to that of the Mediterranese. Their forehead is
-generally high, their nose prominent and narrow, their lips slightly
-protruding. Their language is now very much mixed with Indo-Germanic
-elements, but seems to have been originally derived from a very peculiar
-primæval language.
-
-The _Nubian_ (Homo Nuba) has caused ethnographers no fewer difficulties
-than the Dravida species. By this name we understand not merely the real
-Nubians (Schangallas, or Dongolese), but also their near kinsmen, the
-Fulas, or Fellatas. The real Nubians inhabit the countries of the Upper
-Nile (Dongola, Schangalla, Barabra, Cordofan); the Fulas, or Fellatas,
-on the other hand, have thence migrated far westward, and now inhabit a
-broad tract in the south of the western Sahara, hemmed in between the
-Soudanians in the north and the Nigritos in the south. The Nubian and
-Fula races are generally either classed with negroes or with the Hamitic
-races (thus with Mediterranese), but are so essentially different from
-both that they must be regarded as a distinct species. In former times
-they very probably occupied a large part of north-eastern Africa. The
-skin of the Nubian and Fula races is of a yellowish or reddish brown
-colour, more rarely dark brown or approaching to black. Their hair is
-not woolly but curled, frequently even quite smooth; its colour is dark
-brown or black. Their beard is much more strongly developed than in
-negroes. The oval formation of their faces approaches more to the
-Mediterranean than to the Negro type. Their forehead is high and broad,
-their nose prominent and not flat, their lips not so protruding as in
-the negro. The language of the Nubian races seems to possess no
-relationship to those of genuine negroes.
-
-The _Caucasian_, or _Mediterranean man_ (Homo Mediterraneus), has from
-time immemorial been placed at the head of all races of men, as the most
-highly developed and perfect. It is generally called the Caucasian race,
-but as among all the varieties of the species, the Caucasian branch is
-the least important, we prefer the much more suitable appellation
-proposed by Friedrich Müller, namely, that of Mediterranean, or Midland
-men. For the most important varieties of this species, which are
-moreover the most eminent actors in what is called "Universal History,"
-first rose to a flourishing condition on the shores of the
-Mediterranean. The former area of the distribution of this species is
-expressed by the name of "Indo-Atlantic" species, whereas at present it
-is spread over the whole earth, and is overcoming most of the other
-species in the struggle for existence. In bodily as well as in mental
-qualities, no other human species can equal the Mediterranean. This
-species alone (with the exception of the Mongolian) has had an actual
-history; it alone has attained to that degree of civilization which
-seems to raise man above the rest of nature.
-
-The characteristics which distinguish the Mediterranean from the other
-species of the race are well known. The chief of the external features
-is the light colour of the skin, which however exhibits all shades, from
-pure white or reddish white, through yellow or yellowish brown to dark
-brown or even black brown. The growth of the hair is generally strong,
-the hair of the head more or less curly, the hair of the beard stronger
-than in any of the other species. The form of the skull shows a great
-development in breadth; medium heads predominate upon the whole, but
-long and short heads are also widely distributed. It is only in this one
-species of men that the body as a whole attains that symmetry in all
-parts, and that equal development, which we call the type of perfect
-human beauty. The languages of all the races of this species can by no
-means be traced to a single common primæval language; we must at least
-assume four radically different primæval languages. In accordance with
-this we must also assume within this one species four different races,
-which are only connected at their root. Two of these races, the Basques
-and Caucasians, now exist only as small remnants. The Basques, which in
-earlier times peopled the whole of Spain and the south of France, now
-inhabit but a narrow tract of land on the northern coast of Spain, on
-the Bay of Biscay. The remnant of the Caucasian race (the Daghestans,
-Tschercassians, Mingrelians, and Georgians) are now confined to the
-districts of Mount Caucasus. The language of the Caucasians as well as
-that of the Basques is entirely peculiar, and can be traced neither to
-the Semitic nor to the Indo-Germanic primæval languages.
-
-Even the languages of the two principal races of the Mediterranean
-species--the Semitic and Indo-Germanic--cannot be traced to a common
-origin, and consequently these two races must have separated at a very
-early period. Semites and Indo-Germani are descended from different
-ape-like men. The _Semitic_ race likewise separated at a very early
-period into two diverging branches, namely, into the _Egyptian_ and
-_Arabic_ branches. The _Egyptian_, or _African_ branch, the
-_Dyssemites_--which sometimes under the name of Hamites are entirely
-separated from the Semites--embraces the large group of Berbers, who
-occupy the whole of north Africa, and in earlier times also peopled the
-Canary Islands, and, finally, also the group of the Ethiopians, the
-Bedsha, Galla, Danakil, Somali, and other tribes which occupy all the
-north-eastern shores of Africa as far as the equator. The _Arabic_, or
-_Asiatic_ branch, that is, the _Eusemites_, also called Semites in a
-narrow sense, embrace the inhabitants of the large Arabian peninsula,
-the primæval family of genuine Arabians ("primæval type of the
-Semites"), and also the most highly developed Semitic groups, the Jews,
-or Hebrews, and the Aramæans--the Syrians and Chaldæans. A colony of the
-southern Arabs (the Himjarites), which crossed the Straits of
-Bab-el-Mandeb, has peopled Abyssinia.
-
-Lastly, the Indo-Germanic race, which has far surpassed all the other
-races of men in mental development, separated at a very early period,
-like the Semitic, into two diverging branches, the _Ario-Romaic_ and the
-_Slavo-Germanic_ branches. Out of the former arose on the one hand the
-_Arians_ (Indians and Iranians), on the other the _Græco-Roman_ (Greeks
-and Albanians, Italians and Kelts). Out of the Slavo-Germanic branch
-were developed on the one hand the _Slavonians_ (Russian, Bulgarian,
-Tchec, and Baltic tribes), on the other the _Germani_ (Scandinavians and
-Germans, Netherlanders and Anglo-Saxons). August Schleicher has
-explained, in a very clear genealogical form, how the further
-ramifications of the Indo-Germanic race may be accurately traced in
-detail on the basis of comparative philology.(6) (Compare p. 331.)
-
-The total number of human individuals at present amounts to between
-1,300 and 1,400 millions. In our Tabular Survey (p. 333) 1,350 millions
-has been assumed as the mean number. According to an approximate
-estimate, as far as such a thing is possible, 1,200 millions of these
-are straight-haired men, only about 150 millions woolly-haired. The most
-highly developed species, Mongols and Mediterranese, far surpass all the
-other human species in numbers of individuals, for each of them alone
-comprises about 550 millions. (Compare Friederich Müller's Ethnography,
-p. 30.) Of course the relative number of the twelve species fluctuates
-every year, and that too according to the law developed by Darwin, that
-in the struggle for life the more highly developed, the more favoured
-and larger groups of forms, possess the positive inclination and the
-certain tendency to spread more and more at the expense of the lower,
-more backward, and smaller groups. Thus the Mediterranean species, and
-within it the Indo-Germanic, have by means of the higher development of
-their brain surpassed all the other races and species in the struggle
-for life, and have already spread the net of their dominion over the
-whole globe. It is only the Mongolian species which can at all
-successfully, at least in certain respects, compete with the
-Mediterranean. Within the tropical regions, Negroes, Kaffres, and
-Nubians, as also the Malays and Dravidas, are in some measure protected
-against the encroachments of the Indo-Germanic tribes by their being
-better adapted for a hot climate; the case of the arctic tribes of the
-polar regions is similar. But the other races, which as it is are very
-much diminished in number, will sooner or later completely succumb in
-the struggle for existence to the superiority of the Mediterranean
-races. The American and Australian tribes are even now fast approaching
-their complete extinction, and the same may be said of the Papuans and
-Hottentots.
-
-In now turning to the equally interesting and difficult question of the
-relative _connection_, _migration_, and _primæval home_ of the twelve
-species of men, I must premise the remark that, in the present state of
-our anthropological knowledge, any answer to this question must be
-regarded only as a provisional hypothesis. This is much the same as with
-any genealogical hypothesis which we may form of the origin of kindred
-animal and vegetable species, on the basis of the "Natural System." But
-the necessary uncertainty of these special hypotheses of descent, in no
-way shakes the absolute certainty of the general theory of descent. Man,
-we may feel certain, is descended from Catarrhini, or narrow-nosed apes,
-whether we agree with the polyphylites, and suppose each human species,
-in its primæval home, to have originated out of a special kind of ape;
-or whether, agreeing with the monophylites, we suppose that all the
-human species arose only by differentiation from a single species of
-primæval man (Homo primigenius).
-
-For many and weighty reasons we hold the monophyletic hypothesis to be
-the more correct, and we therefore assume a _single primæval home_ for
-mankind, where he developed out of a long since extinct anthropoid
-species of ape. Of the five now existing continents, neither Australia,
-nor America, nor Europe can have been this primæval home, or the
-so-called "Paradise," the "cradle of the human race." Most
-circumstances indicate southern Asia as the locality in question.
-Besides southern Asia, the only other of the now existing continents
-which might be viewed in this light is Africa. But there are a number of
-circumstances (especially chorological facts) which suggest that the
-primæval home of man was a continent now sunk below the surface of the
-Indian Ocean, which extended along the south of Asia, as it is at
-present (and probably in direct connection with it), towards the east,
-as far as further India and the Sunda Islands; towards the west, as far
-as Madagascar and the south-eastern shores of Africa. We have already
-mentioned that many facts in animal and vegetable geography render the
-former existence of such a south Indian continent very probable.
-(Compare vol. i. p. 361.) Sclater has given this continent the name of
-Lemuria, from the Semi-apes which were characteristic of it. By assuming
-this Lemuria to have been man's primæval home, we greatly facilitate the
-explanation of the geographical distribution of the human species by
-migration. (Compare the Table of Migrations XV., and its explanation at
-the end.)
-
-We as yet know of no fossil remains of the hypothetical primæval man
-(Homo primigenius) who developed out of anthropoid apes during the
-tertiary period, either in Lemuria or in southern Asia, or possibly in
-Africa. But considering the extraordinary resemblance between the lowest
-woolly-haired men, and the highest man-like apes, which still exist at
-the present day, it requires but a slight stretch of the imagination to
-conceive an intermediate form connecting the two, and to see in it an
-approximate likeness to the supposed primæval men, or ape-like men. The
-form of their skull was probably very long, with slanting teeth; their
-hair woolly; the colour of their skin dark, of a brownish tint. The hair
-covering the whole body was probably thicker than in any of the still
-living human species; their arms comparatively longer and stronger;
-their legs, on the other hand, knock-kneed, shorter and thinner, with
-entirely undeveloped calves; their walk but half erect.
-
-This ape-like man very probably did not as yet possess an actual human
-language, that is, an articulate language of ideas. Human speech, as has
-already been remarked, most likely originated after the divergence of
-the primæval species of men into different species. The number of
-primæval languages is, however, considerably larger than the number of
-the species of men above discussed. For philologists have hitherto not
-been able to trace the four primæval languages of the Mediterranean
-species, namely, the Basque, Caucasian, Semitic, and Indo-Germanic to a
-single primæval language. As little can the different Negro languages be
-derived from a common primæval language; hence both these species,
-Mediterranean and Negro, are certainly _polyglottonic_, that is, their
-respective languages originated after the divergence of the speechless
-primary species into several races had already taken place. Perhaps the
-Mongols, the Arctic and American tribes, are likewise polyglottonic. The
-Malayan species is, however, _monoglottonic_; all the Polynesian and
-Sundanesian dialects and languages can be derived from a common, long
-since extinct primæval language, which is not related to any other
-language on earth. All the other human species, Nubians, Dravidas,
-Australians, Papuans, Hottentots, and Kaffres are likewise
-monoglottonic. (Compare p. 333.)
-
-Out of speechless primæval man, whom we consider as the common primary
-species of all the others, there developed in the first place--probably
-by natural selection--various species of men unknown to us, and now long
-since extinct, and who still remained at the stage of speechless ape-men
-(Alalus, or Pithecanthropus). Two of these species, a woolly-haired and
-a straight-haired, which were most strongly divergent, and consequently
-overpowered the others in the struggle for life, became the primary
-forms of the other remaining human species.
-
-The main branch of woolly-haired men (Ulotrichi) at first spread only
-over the southern hemisphere, and then emigrated partly eastwards,
-partly westwards. Remnants of the eastern branch are the Papuans in New
-Guinea and Melanesia, who in earlier times were diffused much further
-west (in further India and Sundanesia), and it was not until a late
-period that they were driven eastwards by the Malays. The Hottentots are
-the but little changed remnants of the western branch; they immigrated
-to their present home from the north-east. It was perhaps during this
-migration that the two nearly related species of Caffres and Negroes
-branched off from them; but it may be that they owe their origin to a
-peculiar branch of ape-like men.
-
-The second main branch of primæval straight-haired men (Lissotrichi),
-which is more capable of development, has probably left a but little
-changed remnant of its common primary form--which migrated to the
-south-east--in the ape-like natives of Australia. Probably very closely
-related to these latter are the South Asiatic _primæval Malays_, or
-_Promalays_, which name we have previously given to the extinct,
-hypothetical primary form of the other six human species. Out of this
-unknown common primary form there seem to have arisen three diverging
-branches, namely, the true Malays, the Mongols, and the Euplocomi; the
-first spread to the east, the second to the north, and the third
-westwards.
-
-The primæval home, or the "Centre of Creation," of the Malays must be
-looked for in the south-eastern part of the Asiatic continent, or
-possibly in the more extensive continent which existed at the time when
-further India was directly connected with the Sunda Archipelago and
-eastern Lemuria. From thence the Malays spread towards the south-east,
-over the Sunda Archipelago as far as Borneo, then wandered, driving the
-Papuans before them, eastwards towards the Samoa and Tonga Islands, and
-thence gradually diffused over the whole of the islands of the southern
-Pacific, to the Sandwich Islands in the north, the Mangareva in the
-east, and New Zealand in the south. A single branch of the Malayan tribe
-was driven far westwards and peopled Madagascar.
-
-The second main branch of primæval Malays, that is, the Mongols, at
-first also spread in Southern Asia, and, radiating to the east, north,
-and north-west, gradually peopled the greater part of the Asiatic
-continent. Of the four principal races of the Mongol species, the
-Indo-Chinese must perhaps be looked upon as the primary group, out of
-which at a later period the other Coreo-Japanese and Ural-Altaian races
-developed as diverging branches. The Mongols migrated in many ways from
-western Asia into Europe, where the species is still represented in
-northern Russia and Scandinavia by the Fins and Lapps, in Hungary by the
-kindred Magyars, and in Turkey by the Osmanlis.
-
-  PEDIGREE OF SEMITES
-
-  Amharites                +Moors+                                     +Jews+
-      |           Tigrites    |             Samaritans                (Hebrews)
-      |  Harrarites  |        |                 |       Phoenicians       |
-      |       |      |        |                 |              |          |
-      |       |      |        |              Chaldeans         |          |
-      \-------v------/        |      Syrians    |              \----v-----/
-       +Abyssinians+          |         |       |               Canaanites
-   Ekilians   |               |         |       |            (+Palestinese+)
-      |       |               |         \---v---/                   |
-      |   Himiarites          |         +Aramæans+                  |
-      |       |               |             |                       |
-      |       |               |             |                       |
-      \---v---/               |             |                       |
-       +South+             +North+          \----------v------------/
-      +Arabians+          +Arabians+             +Primæval Jews+
-          |                   |                  +North-Semites+
-          \-------v-----------/                        |
-       +Arabians+ (+South Semites+)                    |
-                     |                                 |
-                     |                                 |
-                     \----------------------------------------v-----/
-          Guanchites                           +Eusemites+ (+Primæval Semites+)
-    Schuluhs  |            Algerians            (Semites in a narrow sense)
-       |      |   Tunese      |                \------------------------v---/
-       |      |     |         |                                         |
-       |      |     |         |   Tripolitans                           |
-       \---v---/    |         |        |                                |
-       Moroccans    \----v----/        |       +Tuaric+                 |
-           |           Cabyles         |     (+Imoscharh+)              |
-           |             |             |           |                    |
-          \--------------v--------------/          |                    |
-                +Berbers+ (+Amazirh+)              |                    |
-    Gallites             |                         |                    |
-       |   Somalites     |                         |                    |
-       |       |         \------------v-------------/                   |
-       \---v---/  Bedschites        +Libians+         Babylonians   +Eusemites+
-           |          |   Egyptians    |        Primæval   |            |
-           |          |   (+Copts+)    |       Phoenicians |  Assyrians |
-           \----v-----/       |        |           |       |      |     |
-           +Ethiopians+       |        |           |       |      |     |
-                |             |        |           |       |      |     |
-                |             |        |           |       |      |     |
-               \------------v----------/           \-------v------/     |
-                  +Ancient Egyptians+               +Mesopotamians+     |
-                            |                          (extinct)        |
-                            |                              |            |
-                            |                              |            |
-                            \------------v-----------------/            |
-                               +Hamites+ (+Dyssemites+)                 |
-                                         |                              |
-                                         \---------------v--------------/
-                                                    +Semites+
-
-             ----------------------------------------------------------------
-
-PEDIGREE OF THE INDO-GERMANI
-
-                    Ancient Prussians  +Anglo-Saxons+          +High Germans+
-      Lithuanians           |                | Low Germans            |
-            |        Letts  |                |      | Netherlanders   |
-            |          |    |                |      |        |        |
-            |          |    |                |      |        |        |
-            \-----v----/    |                |      \----v---/        |
-                  |         |                |    Ancient Saxons      |
-                  |         |                |           |            |
-                  \-------v-/                |           |            |
-                   +Baltic Races+            \------v----/            |
-             Sorbians, or |                      Saxons   Friesians   |
-                 Wends    |                         |         |       |
-            Poles  |      |                         |         |       |
-              |    |      |                         \----v----/       |
-    Czecs     |    |      |                        +Low Germans+      |
-      |       |    |      |                              |            |
-      |       |    |      |                              |            |
-    \--v-----------/      |  Scandinavians               \-----v------/
-  West Sclavonians        |        |          Goths        +Germans+
-       |         Russians |        |           |               |
-       |   South    |     |        |           |               |
-       | Sclavonians|     |        \----v----------------------/
-       |      |     |     |    +Primæval Germans+               Ancient Britons
-       |      |     |     |             |                             |
-       |     \---v---/    |             |               Ancient Scots |  Gauls
-       |   South-eastern  |             | +Romans+        Irish |     |    |
-       |    Sclavonians   |             |    |             |    |     |    |
-       |         |        |             |    |             |    |     \--v-/
-       |         |        |             |    |             \--v-/   Brittanese
-       |         |        |             |    | +Latins+     Gaels        |
-       \----v----/        |             |    |     |          |          |
-      +Sclavonians+       |             |    |     |          |          |
-            |             |             |    \--v--/          \----v-----/
-            |             |             |    Italians           +Kelts+
-            \------v------/             |       |                  |
-             +Sclavo-Letts+             |       |                  |
-                   |                    |       \--------v---------/
-                   |                    |           +Italo-Kelts+
-                   \--v-----------------/                |
-             +Sclavo-Germans+  +Albanese+  +Greeks+      |
-                      |             |          |         |
-                      |             |          |         |
-                      |             \----v-----/         |
-                      |        +Primæval Thracians+      |
-                      | +Indians+        |               |
-                      |     | +Iranians+ \-------v-------/
-                      |     |      |       +Græco-Romans+
-                      |     \---v--/             |
-                      |     +Arians+             |
-                      |         |                |
-                      |         \-----v----------/
-                      |          +Ario-Romans+
-                      |               |
-                      \-------v-------/
-                        +Indo-Germans+
-
-
-On the other hand, a branch of the Mongols migrated from north-eastern
-Asia to America, which was probably in earlier times connected with the
-former continent by a broad isthmus. The Arctic tribes, or Polar men,
-the Hyperboreans of north-eastern Asia, and the Esquimaux of the
-extreme north of America, must probably be regarded as an offshoot of
-this branch, which became peculiarly degenerated by unfavourable
-conditions of existence. The principal portion of the Mongolian
-immigrants, however, migrated to the south, and gradually spread over
-the whole of America, first over the north, later over South America.
-
-The third and most important main branch of primæval Malays, the
-curly-haired races, or Euplocomi, have probably left in the Dravidas of
-Hindostan and Ceylon, that species of man which differs least from the
-common primary form of the Euplocomi. The principal portion of the
-latter, namely, the Mediterranean species, migrated from their primæval
-home (Hindostan?) westwards, and peopled the shores of the
-Mediterranean, south-western Asia, north Africa, and Europe. The
-Nubians, in the north-east of Africa, must perhaps be regarded as an
-offshoot of the primæval Semitic tribes, who migrated far across central
-Africa almost to the western shores. The various branches of the
-Indo-Germanic race have deviated furthest from the common primary form
-of ape-like men. During classic antiquity and the middle ages, the
-Romanic branch (the Græco-Italo-Keltic group), one of the two main
-branches of the Indo-Germanic species, outstripped all other branches in
-the career of civilization, but at present the same position is occupied
-by the Germanic. Its chief representatives are the English and Germans,
-who are in the present age laying the foundation for a new period of
-higher mental development, in the recognition and completion of the
-theory of descent. The recognition of the theory of development and the
-monistic philosophy based upon it, forms the best criterion for the
-degree of man's mental development.
-
-
-SYSTEMATIC SURVEY OF THE TWELVE HUMAN SPECIES.
-
-   N.B.--Column A denotes the Average Number of the Population in
-   millions. Column B shows the Degree of the Phyletic Development of
-   the Species, thus Pr = Progressive Diffusion; Co = Comparative
-   Stability; Re = Retrogression and Extinction. Column C denotes the
-   Character of the Primæval Language; Mn (Monoglottonic) signifies that
-   the Species had one Simple Primæval Language; Pl (Polyglottonic) a
-   Compound Primæval Language.
-
-
-  ----------------------+--------------------+--------+-------+--------+-----------------------------
-  _Tribe._              |    _Human          |   A.   |  B.   |   C.   |             _Home._
-                        |     Species._      |        |       |        |
-  ----------------------+--------------------+--------+-------+--------+-----------------------------
-
-  TUFT-HAIRED            {                   |        |       |
-  +Lophocomi+            {  1. PAPUAN        |   2    |  Re   |  Mn    { New Guinea and Melanesia,
-                         {                   |        |       |        { Philippine Islands, Malacca
-  (about 2 millions)     {  2. HOTTENTOT     | 1/20   |  Re   |  Mn    { The extreme south of Africa
-                         {                   |        |       |        { (The Cape)
-                                             |        |       |
-  FLEECY-HAIRED          {  3. KAFFRE        |   20   |  Pr   |  Mn    { South Africa (between 30°
-                         {                   |        |       |        { S. Lat. and 5° N. Lat.)
-  +Eriocomi+             {  4. NEGRO         |   130  |  Pr   |  Pl    { Central Africa (between the
-                         {                   |        |       |        { Equator and 30° N. Lat.)
-  (about 150 millions)   {                   |        |       |
-                                             |        |       |
-                         {  5. AUSTRALIAN    |  1/12  |   Re  |  Mn    { Australia
-                         {  6. MALAY         |   30   |   Co  |  Mn    { Malacca, Sundanesia, Polynesia,
-                         {                   |        |       |        { and Madagascar
-  STRAIGHT-HAIRED        {                   |        |       |
-  +Euthycomi+            {  7. MONGOL        |   550  |   Pr  |  Mn?   { The greater part of Asia
-                         {                   |        |       |        { and northern Europe
-  (about 600 millions)   {  8. ARCTIC        |  1/25  |   Co  |  Pl?   { The extreme north-east of
-                         {     MAN           |        |       |        { Asia and the extreme north
-                         {                   |        |       |        { of America
-                         {  9. AMERICAN      |   12   |   Re  |  Mn?   { The whole of America with
-                         {                   |        |       |        { the exception of the extreme
-                         {                   |        |       |        { north
-                                             |        |       |
-                         { 10. DRAVIDAS      |   34   |   Co  |  Mn    { South Asia (Hindostan and
-                         {                   |        |       |        { Ceylon)
-                         {                   |        |       |
-                         { 11. NUBIAN        |   10   |   Co  |  Mn?   { Central Africa (Nubia and
-                         {                   |        |       |        { Fula-land)
-  CURLY-HAIRED           {                   |        |       |        { In all parts of the world,
-                         {                   |        |       |        { having migrated from South
-  +Euplocomi+            { 12. MEDITERRANEAN |  550   |  Pr   |  Pl    { Asia to North Africa and
-                         {                   |        |       |        { South Europe
-  (about 600 millions)   {                   |        |       |
-                         {                   |        |       |
-                                             |        |       |        { In all parts of the world,
-                           13. HYBRIDS       |   11   |   Pr  |  Pl    { but predominating in America
-                              OF THE         |        |       |        { and Asia
-                              SPECIES        |        |       |
-                         --------------------+--------+       |
-                               TOTAL              1350
-
-
-
-
-CHAPTER XXIV.
-
-OBJECTIONS AGAINST, AND PROOFS OF THE TRUTH OF, THE THEORY OF DESCENT.
-
-
-  Objections to the Doctrine of Filiation.--Objections of Faith
-  and Reason.--Immeasurable Length of the Geological
-  Periods.--Transition Forms between Kindred Species.--Dependence
-  of Stability of Form on Inheritance, and of the Variability of
-  Form on Adaptation.--Origin of very complicated Arrangement of
-  Organisation.--Gradual Development of Instincts and Mental
-  Activities.--Origin of a priori Knowledge from Knowledge a
-  posteriori.--The Knowledge requisite for the Correct
-  Understanding of the Doctrine of Filiation.--Necessary
-  Interaction between Empiricism and Philosophy.--Proofs of the
-  Theory of Descent.--Inner Causal Connection between all the
-  Biological Series of Phenomena.--The Direct Proof of the Theory
-  of Selection.--Relation of the Theory of Descent to
-  Anthropology.--Proofs of the Animal Origin of Man.--The Pithecoid
-  Theory as an Inseparable Part of the Theory of
-  Descent.--Induction and Deduction.--Gradual Development of the
-  Human Mind.--Body and Mind.--Human Soul and Animal Soul.--A Glance
-  at the Future.
-
-
-If in these chapters I may hope to have made the Theory of Descent seem
-more or less probable, and to have even convinced some of my readers of
-its unassailable truth, yet I am by no means unconscious that, to most
-of them, during the perusal of my explanations, a number of objections
-more or less well founded must have occurred. Hence it seems absolutely
-necessary at the conclusion of our examination to refute at least the
-most important of these, and at the same time, on the other hand, once
-more to set forth the convincing arguments which bear testimony to the
-truth of the theory of development.
-
-The objections which are raised to the doctrine of descent may be
-divided into two large groups: objections of faith and objections of
-reason. The objections of the first group originate in the infinitely
-varied forms of faith held by human individuals, and need not here be
-taken into consideration at all. For, as I have already remarked at the
-beginning of this book, science, as an objective result of sensuous
-experience, and of the striving of human reason after knowledge, has
-nothing whatever to do with the subjective ideas of faith, which are
-preached by a single man as the direct inspirations or revelations of
-the Creator, and then believed in by the dependent multitude. This
-belief, very different in different nations, only begins, as is well
-known, where science ends. Natural Science believes, according to the
-maxim of Frederick the Great, "that every one may go to heaven in his
-own fashion," and only necessarily enters into conflict with particular
-forms of faith where they appear to set a limit to free inquiry and a
-goal to human knowledge, beyond which we are not to venture. Now this is
-certainly the case here in the highest degree, for the Theory of
-Development applies itself to the solution of the greatest of scientific
-problems--that of the creation, the coming into existence of things;
-more especially the origin of organic forms, and of man at their head.
-It is here certainly the right as well as the sacred duty of free
-inquiry, to fear no human authority, and courageously to raise the veil
-from the image of the Creator, unconcerned as to what natural truth may
-lie concealed beneath. The only Divine revelation which we recognise as
-true, is written everywhere in nature, and to every one with healthy
-senses and a healthy reason it is given to participate in the unerring
-revelation of this holy temple of nature, by his own inquiry and
-independent discovery.
-
-If we, therefore, here disregard all objections to the Doctrine of
-Descent which may be raised by the priests of the different religious
-faiths, we must nevertheless endeavour to refute the most important of
-those objections which seem more or less founded on science, and which
-we grant might, at first sight, to a certain extent captivate us and
-deter us from adopting the Doctrine of Descent. Many persons seem to
-think the length of the periods of time required the most important of
-these objections. We are not accustomed to deal with such immense
-periods as are necessary for the history of the creation. It has already
-been mentioned that the periods, during which species originated by
-gradual transmutation, must not be calculated by single centuries, but
-by hundreds and by millions of centuries. Even the thickness of the
-stratified crust of the earth, the consideration of the immense space of
-time which was requisite for its deposition from water, taken together
-with the periods of elevation between the periods of depression,
-indicate a duration of time of the organic history of the earth which
-the human intellect cannot realize. We are here in much the same
-position as an astronomer in regard to infinite space. In the same way
-as the distances between the different planetary systems are not
-calculated by miles but by Sirius-distances, each of which comprises
-millions of miles, so the organic history of the earth must not be
-calculated by thousands of years, but by palæontological or geological
-periods, each of which comprises many thousands of years, and perhaps
-millions, or even, milliards, of thousands of years. It is of little
-importance how high the immeasurable length of these periods may be
-approximately estimated, because we are in fact unable with our limited
-power of imagination to form a true conception of these periods, and
-because we do not as in astronomy possess a secure mathematical basis
-for fixing the approximate length of duration in numbers. But we most
-positively deny that we see any objection to the theory of development
-in the extreme length of these periods which are so completely beyond
-the power of our imagination. It is, on the contrary, as I have already
-explained in one of the preceding chapters, most advisable, from a
-strictly philosophical point of view, to conceive these periods of
-creation to be as long as possible, and we are by so much the less in
-danger of losing ourselves in improbable hypotheses, the longer we
-conceive the periods for organic processes of development to have been.
-The longer, for example, we conceive the Permian period to have been,
-the easier it will be for us to understand how the important
-transmutations took place within it which so essentially distinguish the
-fauna and flora of the Coal period from that of the Trias. The great
-disinclination which most persons have to assume such immeasurable
-periods, arises mainly from the fact of our having in early youth been
-brought up in the notion that the whole earth is only some thousands of
-years old. Moreover, human life, which at most attains the length of a
-century, is an extremely short space of time, and is not suitable as a
-standard for the measurement of geological periods. Our life is a
-single drop in the ocean of eternity. The reader may call to mind the
-duration of life of many trees which is more than fifty times as long;
-for example, the dragon-trees (Dracæna) and monkey bread-fruit trees
-(Adansonia), whose individual life exceeds a period of five thousand
-years; and, on the other hand, the shortness of the individual life of
-many of the lower animals, for example, the infusoria, where the
-individual, as such, lives but a few days, or even but a few hours,
-contrasts no less strongly with human longevity. This comparison brings
-the relative nature of all measurement of time very clearly before us.
-If the theory of development be true at all, there must certainly have
-elapsed immense periods, utterly inconceivable to us, during which the
-gradual historical development of the animal and vegetable kingdom
-proceeded by the slow transformation of species. There is, however, not
-a single reason for accepting a definite limit for the length of these
-periods of development.
-
-A second main objection which many, and more especially systematic
-zoologists and botanists, raise against the theory of descent, is that
-no _transition forms_ between the different species can be found,
-although according to the theory of descent they ought to be found in
-great numbers. This objection is partly well founded and partly not so,
-for there does exist an extraordinarily large number of transition forms
-between living, as well as between extinct species, especially where we
-have an opportunity of seeing and comparing very numerous individuals of
-kindred species. Those careful investigators of individual species who
-so frequently raise this objection are the very persons whom we
-constantly find checked in their special series of investigations by the
-really insuperable difficulty of sharply distinguishing individual
-species. In all systematic works, which are in any degree thorough, one
-meets with endless complaints, that here and there species cannot be
-distinguished because of the excessive number of transition forms. Hence
-every naturalist defines the limit and the number of individual species
-differently. Some zoologists and botanists, as I mentioned (vol. i. p.
-276), assume in one and the same group of organisms ten species, others
-twenty, others a hundred or more, while other systematic naturalists
-again look upon these different forms only as varieties of a single
-"good" species. In most groups of forms there is, in fact, a
-superabundance of transition forms and intermediate stages between the
-individual species.
-
-It is true that in many species the forms of transition are actually
-wanting, but this is easily explained by the principle of divergence or
-separation, the importance of which I have already explained. The
-circumstance that the struggle for existence is the more active between
-two kindred forms the closer they stand to each other, must necessarily
-favour the speedy extinction of the connecting intermediate forms
-between the two divergent species. If one and the same species produce
-diverging varieties in different directions, which become new species,
-the struggle between these new forms and the common primary form will be
-the keener the less they differ from one another; but the stronger the
-divergence the less dangerous the struggle. Naturally therefore, it is
-principally the connecting intermediate forms which will in most cases
-quietly die out, while the most divergent forms remain and reproduce
-themselves as distinct "new species." In accordance with this, we in
-fact no longer find forms of transition leading to those groups which
-are becoming extinct, as, for example, among birds, are the ostriches;
-and among mammals, the elephants, giraffes, Semi-apes, Edentata, and
-Ornithorhyncus. The groups of forms approaching their extinction no
-longer produce new varieties, and naturally the species are what is
-called "good," that is, the species are distinctly different from one
-another. But in those animal groups where development and progress are
-still active, where the existing species deviate into many new species
-by the formation of new varieties, we find an abundance of transition
-forms which cause the greatest difficulties to systematic naturalists.
-This is the case, for example, among birds with the finches; among
-mammals with most of the rodents (more especially with those of the
-mouse and rat kind), with a number of the ruminants and with genuine
-apes, more especially with the South American forms (Cebus), and many
-others. The continual development of species by the formation of new
-varieties here produces a mass of intermediate forms which connect the
-so-called "good" species, which efface their boundaries, and render
-their sharp specific distinction completely illusory.
-
-The reason that this nevertheless does not cause a complete confusion of
-forms, nor a universal chaos in the structure of animals and vegetables,
-lies simply in the fact that there is a continual counteraction at work
-between progressive _adaptation_ on the one hand, and the _retentive_
-power of _inheritance_ on the other hand. The degree of stability and
-variability manifested by every organic form is determined solely by the
-actual condition of the equilibrium between these two opposite
-functions. _Inheritance is the cause of the stability of species,
-adaptation the cause of their modification._ When therefore some
-naturalists say that, according to the theory of descent, there ought to
-be a much greater variety of forms, and others again, that there ought
-to be a much greater equality of forms, the former under-estimate the
-value of inheritance and the latter the value of adaptation. _The ratio
-of the interaction between inheritance and adaptation determines the
-ratio of the stability and variability of organic species_ at any given
-period.
-
-Another objection to the theory of descent, which, in the opinion of
-many naturalists and philosophers is of great weight, is that it
-ascribes the origin of organs which act for a definite purpose to causes
-which are either aimless or mechanical in their operation. This
-objection seems to be especially important in regard to those organs
-which appear so excellently adapted for a certain definite purpose that
-the most ingenious mechanician could not invent a more perfect organ for
-the purpose. Such are, above all, the higher sense-organs of animals,
-the eye and ear. If the eyes and auditory apparatus of the higher
-animals alone were known to us, they would indeed cause great and
-perhaps insurmountable difficulties. How could we come to the conclusion
-that the extraordinarily great and wonderful degree of perfection and
-conformity to purpose which we perceive in the eyes and ears of higher
-animals, is in every respect attained solely by natural selection?
-Fortunately, however, comparative anatomy and the history of
-development help us here over all obstacles; for when in the animal
-kingdom we follow the gradual progress towards perfection of the eyes
-and ears, step by step, we find such a finely graduated series of
-improvement, that we can clearly follow the development of the most
-complex organs through all the stages towards perfection. Thus, for
-example, the eye in the lowest animal is a simple spot of pigment which
-does not yet reflect any image of external objects, but at most
-perceives and distinguishes the different rays of light. Later, we find
-in addition to this a sensitive nerve; then there gradually develops
-within the spot of pigment the first beginning of the lens, a refractive
-body which is now able to concentrate the rays of light and to reflect a
-definite image. But all the composite apparatus for the movement of the
-eye and its accommodation to variations of light and distance are still
-absent, namely, the various refractive media, the highly differentiated
-membrane of the optic nerve, etc., which are so perfectly constructed in
-higher animals. Comparative anatomy shows us an uninterrupted succession
-of all possible stages of transition, from the simplest organ to the
-most highly perfected apparatus, so that we can form a pretty correct
-idea of the slow and gradual formation of even such an exceedingly
-complex organ. The like gradual progress which we observe in the
-development of the organ during the course of individual development,
-must have taken place in the historical (phyletic) origin of the organ.
-
-Many persons when contemplating these most perfect organs--which
-apparently were purposely invented and constructed by an ingenious
-Creator for a definite function, but which in reality have arisen by the
-aimless action of natural selection--experience difficulties in arriving
-at a rational understanding of them, which are similar to those
-experienced by the uncivilized tribes of nature when contemplating the
-latest complicated productions of engineering. Savages who see a ship of
-the line, or a locomotive engine for the first time, look upon these
-objects as the productions of a supernatural being, and cannot
-understand how a man, an organism like themselves, could have produced
-such an engine. Even the uneducated classes of our own race cannot
-comprehend such an intricate apparatus in its actual workings, nor can
-they understand its purely mechanical nature. Most naturalists, however,
-as Darwin very justly remarks, stand in much the same position in regard
-to the forms of organisms as do savages to ships of the line and to
-locomotive engines. A rational understanding of the purely mechanical
-origin of organic forms can only be acquired by a thorough and general
-training in Biology, and by a special knowledge of comparative anatomy
-and the history of development.
-
-Among the remaining objections to the Theory of Descent, I shall here
-finally refer to and refute but one more, as in the eyes of many
-unscientific men it seems to possess great weight. How are we, from the
-Theory of Descent, to conceive of the origin of the mental faculties of
-animals, and more especially their specific expressions--the so-called
-instincts? This difficult subject has been so minutely discussed by
-Darwin in a special chapter of his chief work (the seventh), that I must
-refer the reader to it. We must regard instincts as essentially the
-habits of the soul acquired by adaptation, and transmitted and fixed by
-inheritance through many generations. Instincts are, therefore, like all
-other habits, which, according to the laws of cumulative adaptation
-(vol. i. p. 233) and established inheritance (vol. i. p. 216), lead to
-the origin of new functions, and thus also to new forms of the organs.
-Here, as everywhere, the interaction between function and organ goes
-hand in hand. Just as the mental faculties of man have been acquired by
-the progressive adaptation of the brain, and been fixed by continual
-transmission by inheritance, so the instincts of animals, which differ
-from them only in quantity, not in quality, have arisen by the gradual
-perfecting of their mental organ, that is, their central nervous system,
-by the interaction of Adaptation and Inheritance. Instincts, as is well
-known, are inherited, but experiences and, consequently, new adaptations
-of the animal mind, are also transmitted by inheritance; and the
-training of domestic animals to different mental activities, which wild
-animals are incapable of accomplishing, rests upon the possibility of
-mental adaptation. We already know a series of examples, in which such
-adaptations, after they had been transmitted through a succession of
-generations, finally appeared as innate instincts, and yet they have
-only been acquired from the ancestors of the animals. Inheritance has
-here caused the result of training to become instinct. The
-characteristic instincts of sporting dogs, shepherd's dogs, and other
-domestic animals, and the natural instincts of wild animals, which they
-possess at birth, were in the first place acquired by their ancestors by
-adaptation. They may in this respect be compared to man's "knowledge a
-priori," which, like all other knowledge, was originally acquired by our
-remote ancestors, "a posteriori," by sensuous experience. As I have
-already remarked, it is evident that "knowledge a priori" arose only by
-long-enduring transmission, by inheritance of acquired adaptations of
-the brain, out of originally empiric or experiential "knowledge a
-posteriori" (vol. i. p. 31).
-
-The objections to the Theory of Descent here discussed and refuted are,
-I believe, the most important which have been raised against it; I
-consider also that I have sufficiently proved to the reader their
-futility. The numerous other objections which besides these have been
-raised against the Theory of Development in general, or against its
-biological part, the Theory of Descent in particular, arise either from
-such a degree of ignorance of empirically established facts, or from
-such a want of their right understanding, and from such an incapacity to
-draw the necessary conclusions, that it is really not worth the trouble
-to go further into the refutation. There are only some general points in
-regard to which, I should like, in a few words, to draw attention.
-
-In the first place I must observe, that in order thoroughly to
-understand the doctrine of descent, and to be convinced of its absolute
-truth, it is indispensable to possess a general knowledge of the whole
-of the domain of biological phenomena. _The theory of descent is a
-biological theory_, and hence it may with fairness and justice be
-demanded that those persons who wish to pass a valid judgment upon it
-should possess the requisite degree of biological knowledge. Their
-possessing a special empiric knowledge of this or that domain of zoology
-or botany, is not sufficient; they must possess a _general insight into
-the whole series of phenomena_, at least in the case of one of the three
-organic kingdoms. They ought to know what universal laws result from the
-comparative morphology and physiology of organisms, but more especially
-from comparative anatomy, from the individual and the palæontological
-history of development, etc.; and they ought to have some idea of the
-deep _mechanical, causal connection_ between all these series of
-phenomena. It is self-evident that a certain degree of general culture,
-and especially a philosophical education, is requisite; which is,
-however, unfortunately by many persons in our day, not considered at all
-necessary. _Without the necessary connection of empirical knowledge and
-the philosophical understanding of biological phenomena, it is
-impossible to gain a thorough conviction of the truth of the Theory of
-Descent._
-
-Now I ask, in the face of this first preliminary condition for a true
-understanding of the Theory of Descent, what we are to think of the
-confused mass of persons who have presumed to pass a written or oral
-judgment upon it of an adverse character? Most of them are unscientific
-persons, who either know nothing of the most important phenomena of
-Biology, or at least possess no idea of their deeper significance. What
-should we say of an unscientific person who presumed to express an
-opinion on the cell-theory, without ever having seen cells; or of one
-who presumed to question the vertebral-theory, without ever having
-studied comparative anatomy? And yet one may meet with such ridiculous
-arrogance any day in the history of the biological Theory of Descent.
-One hears thousands of unscientific and but half-educated persons pass a
-final judgment upon it, although they know nothing either of botany or
-of zoology, of comparative anatomy or the theory of tissues, of
-palæontology or embryology. Hence it happens, as Huxley well says, that
-most of the writings published against Darwin are not worth the paper
-upon which they are written.
-
-We might add that there are many naturalists, and even celebrated
-zoologists and botanists, among the opponents of the Theory of Descent;
-but these latter are mostly old stagers, who have grown grey in quite
-opposite views, and whom we cannot expect, in the evening of their
-lives, to submit to a reform in their conception of the universe, which
-has become to them a fixed idea.
-
-It is, moreover, expressly to be remarked, that not only a general
-insight into the _whole_ domain of biological phenomena, but also a
-philosophical understanding of it, are the necessary preliminary
-conditions for becoming convinced of and adopting the Theory of Descent.
-Now we shall find that these indispensable preliminary conditions are,
-unfortunately, by no means fulfilled by the majority of naturalists of
-the present day. The immense amount of empirical facts with which the
-gigantic advances of modern natural science have recently made us
-acquainted has led to a prevailing inclination for the special study of
-single phenomena and of small and narrow domains. This causes the
-knowledge of other paths, and especially of Nature as a great
-comprehensive whole, to be in most cases completely neglected. Every one
-with sound eyes and a microscope, together with industry and patience
-for study, can in our day attain a certain degree of celebrity by
-microscopic "discoveries," without, however, deserving the name of a
-naturalist. This name is deserved only by him who not merely strives to
-_know_ the individual phenomena, but who also seeks to _discover_ their
-causal connection. Even in our own day, most palæontologists examine and
-describe fossils without knowing the most important facts of embryology.
-Embryologists, on the other hand, follow the history of development of a
-particular organic individual, without having an idea of the
-palæontological history of the whole tribe, of which fossils are the
-records. And yet these two branches of the organic history of
-development--ontogeny, or the history of the individual, and phylogeny,
-or the history of the tribe--stand in the closest causal connection, and
-the one cannot be understood without the other. The same may be said of
-the systematic and the anatomical part of Biology. There are even now,
-in zoology and botany, many systematic naturalists who work with the
-erroneous idea that it is possible to construct a natural system of
-animals and plants simply by a careful examination of the external and
-readily accessible forms of bodies, without a deeper knowledge of their
-internal structure. On the other hand, there are anatomists and
-histologists who think it possible to obtain a true knowledge of animal
-and vegetable bodies merely by a most careful examination of the inner
-structure of the body of some individual species, without the
-comparative examination of the bodily form of all kindred organisms. And
-yet here, as everywhere, the internal and external factors, to wit,
-Inheritance and Adaptation, stand in the closest mutual relation, and
-the individual can never be thoroughly understood without a comparison
-of it with the whole of which it is a part. To those one-sided
-specialists we should like in Goethe's words to say:--
-
-  We must, contemplating Nature,
-  Part as Whole, give equal heed to:
-  Nought is inward, nought is outward,
-  For the inner is the outer.[6]
-
-And again:--
-
-  Nature has neither kernel nor shell,
-  It is she that is All and All at once.[7]
-
-What is even more detrimental to the general understanding of nature as
-a whole than this one-sided tendency, is _the want of a philosophical
-culture_, and this applies to most of the naturalists of the present
-day. The various errors of the earlier speculative nature-philosophy
-made during the first thirty years of our century, have brought the
-whole of philosophy into such bad repute with the exact empirical
-naturalists, that they live in the strange delusion that it is possible
-to erect the edifice of natural science out of mere facts, without their
-philosophic connection; in short, out of mere knowledge, without the
-understanding of it. But as a purely speculative and absolutely
-philosophical system, which does not concern itself with the
-indispensable foundation of empirical facts, becomes a castle in the
-air, which the first real experiment throws to the winds; so, on the
-other hand, a purely empirical system, constructed of nothing but facts,
-remains a disorderly heap of stones, which will never deserve the name
-of an edifice. Bare facts established by experience are nothing but rude
-stones, and without their thoughtful valuation, without their
-philosophic connection, no science can be established. As I have already
-tried to impress upon my reader, the _strong edifice of true monistic
-science_, or what is the same thing, the _Science of Nature, exists only
-by the closest interaction, and the reciprocal penetration of philosophy
-and empirical knowledge_.
-
-This lamentable estrangement between science and philosophy, and the
-rude empiricism which is now-a-days unfortunately praised by most
-naturalists as "exact science," have given rise to those strange freaks
-of the understanding, to those gross insults against elementary logic,
-and to that incapacity for forming the simplest conclusions which one
-may meet with any day in all branches of science, but especially in
-zoology and botany. It is here that the neglect of a philosophical
-culture and training of the mind, directly avenges itself most
-painfully. It is not to be wondered at that the deep inner truth of the
-Theory of Descent remains a sealed book to those rude empiricists. As
-the common proverb justly says: they cannot see the wood for the trees.
-It is only by a more general philosophical study, and especially by a
-more strictly logical training of the mind, that this sad state of
-things can be remedied. (Compare Gen. Morph. i. 63; ii. p. 447.)
-
-If we rightly consider this circumstance, and if we further reflect upon
-it in connection with the empirical foundation of the philosophical
-theory of development, we shall at once see how we are placed respecting
-the oft-demanded _proofs of the theory of descent_. The more the
-doctrine of filiation has of late years made way for itself, and the
-more all thoughtful, younger naturalists, and all truly
-biologically-educated philosophers have become convinced of its inner
-truth and absolute necessity, the louder have its opponents called for
-actual proofs. The same persons who, shortly after the publication of
-Darwin's work, declared it to be "a groundless, fantastic system," an
-"arbitrary speculation," an "ingenious dream," now kindly condescend to
-declare that the theory of descent certainly is a scientific
-"_hypothesis_," but that it still requires to be "_proved_." When these
-remarks are made by persons who do not possess the requisite
-empirico-philosophical culture, nor the necessary knowledge in
-comparative anatomy, embryology, and palæontology, we cannot be much
-offended, and we refer them to the study of those sciences. But when
-similar remarks are made by acknowledged specialists, by teachers of
-zoology and botany, who certainly ought to possess a general insight
-into the whole domain of their science, or who are actually familiar
-with the facts of those scientific domains, then we are really at a loss
-what to say. Those who are not satisfied with the treasures of our
-present empirical knowledge of nature as a basis on which to establish
-the Theory of Descent, will not be convinced by any other facts which
-may hereafter be discovered; for we can conceive no circumstances which
-would furnish stronger or a more complete testimony to the truth of the
-doctrine of filiation than is even now seen, for example, in the
-well-known facts of comparative anatomy and ontogeny. I must here again
-direct attention to the fact, _that all the great and general laws, and
-all the comprehensive series of phenomena of the most different domains
-of biology can only be explained and understood by the Theory of
-Development_ (and especially by its biological part, the Theory of
-Descent), and that without it they remain completely inexplicable and
-incomprehensible. _The internal causal connection_ between them all
-proves the Theory of Descent to be the greatest _inductive law_ of
-Biology.
-
-Before concluding, I will once more name all those series of inductions,
-all those general laws of Biology, upon which this comprehensive law of
-development is firmly based.
-
-(1.) _The palæontological history of the development of organisms_, the
-gradual appearance and the historical succession of the different
-species and groups of species, the empirical laws of the palæontological
-change of species, as furnished to us by the science of fossils, and
-more especially the _progressive differentiation and perfecting_ of
-animal and vegetable groups in the successive periods of the earth's
-history.
-
-(2.) _The individual history of development of organisms_, embryology
-and metamorphology, the gradual changes in the slow development of the
-body and its particular organs, especially _the progressive
-differentiation and perfecting_ of the organs and parts of the body in
-the successive periods of the individual development.
-
-(3.) _The inner causal connection between ontogeny and phylogeny_, the
-parallelism between the individual history of the development of
-organisms, and the palæontological history of the development of their
-ancestors, a connection which is actually established by the laws of
-_Inheritance_ and _Adaptation_, and which may be summed up in the words:
-ontogeny, according to the laws of inheritance and adaptation, repeats
-in its large features the outlines of phylogeny.
-
-(4.) _The comparative anatomy of organisms_, the proof of the essential
-agreement of the inner structure of kindred organisms, in spite even of
-the greatest difference of external form in the various species; their
-explanation by the causal dependence of the internal agreement of the
-structure on _Inheritance_, the external dissimilarity of the bodily
-form on _Adaptation_.
-
-(5.) _The inner causal connection between comparative anatomy and the
-history of development_, the harmonious agreement between the laws of
-the gradual development, _the progressive differentiation and
-perfecting_, as they may be seen in comparative anatomy on the one hand,
-in ontogeny and palæontology on the other.
-
-(6.) _Dysteleology, or the theory of purposelessness_, the name I have
-given to the _science of rudimentary organs_, of suppressed and
-degenerated, aimless and inactive, parts of the body; one of the most
-important and most interesting branches of comparative anatomy, which,
-when rightly estimated, is alone sufficient to refute the fundamental
-error of the teleological and dualistic conception of Nature, and to
-serve as the foundation of the mechanical and monistic conception of the
-universe.
-
-(7.) _The natural system of organisms_, the natural grouping of all the
-different forms of Animals, Plants, and Protista into numerous smaller
-or larger groups, arranged beside and above one another; the kindred
-connection of species, genera, families, orders, classes, tribes, etc.,
-more especially, however, the _arboriform branching character of the
-natural system_, which is the spontaneous result of a natural
-arrangement and classification of all these graduated groups or
-categories. The result attained in attempting to exhibit the
-relationships of the mere forms of organisms by a tabular classification
-is only explicable when regarded as the expression of their actual
-_blood relationship_; _the tree shape of the natural system_ can only be
-understood as the actual _pedigree of the organisms_.
-
-(8.) _The chorology of organisms_, the science of the local distribution
-of organic species, of their _geographical_ and _topographical
-dispersion over the surface of the earth_, over the heights of
-mountains and in the depths of the ocean, but especially the important
-phenomenon that every species of organism proceeds from a so-called
-"_centre of creation_" (more correctly a "_primæval home_" or "_centre
-of distribution_"); that is, from a single locality, where it originated
-but once, and whence it spread.
-
-(9.) _The oecology of organisms_, the knowledge of the sum of the
-_relations of organisms to the surrounding outer world_, to organic and
-inorganic conditions of existence; the so-called "_economy of nature_,"
-the correlations between all organisms living together in one and the
-same locality, their adaptation to their surroundings, their
-modification in the struggle for existence, especially the circumstances
-of parasitism, etc. It is just these phenomena in "the economy of
-nature" which the unscientific, on a superficial consideration, are wont
-to regard as the wise arrangements of a Creator acting for a definite
-purpose, but which on a more attentive examination show themselves to be
-the necessary results of mechanical causes.
-
-(10.) _The unity of Biology as a whole_, the deep inner connection
-existing between all the phenomena named and all the other phenomena
-belonging to zoology, protistics, and botany, and which are simply and
-naturally explained by a single common principle. This principle can be
-no other than the common derivation of all the specifically different
-organisms from a single, or from several absolutely simple, primary
-forms like the Monera, which possess no organs. The Theory of Descent,
-by assuming this common derivation, throws a clear light upon these
-individual series of phenomena, as well as upon their totality, without
-which their deeper causal connection would remain completely
-incomprehensible to us. The opponents of the Theory of Descent can in no
-way explain any single one of these series of phenomena or their deeper
-connection with one another. So long as they are unable to do this, _the
-Theory of Descent remains the one adequate biological theory_.
-
-We should, on account of the grand proofs just enumerated, have to adopt
-Lamarck's Theory of Descent for the explanation of biological phenomena,
-even if we did not possess Darwin's Theory of Selection. The one is so
-completely and _directly proved_ by the other, and established by
-mechanical causes, that there remains nothing to be desired. The laws of
-_Inheritance_ and _Adaptation_ are universally acknowledged
-_physiological_ facts, the former traceable to _propagation_, the latter
-to the _nutrition_ of organisms. On the other hand, the _struggle for
-existence_ is a _biological_ fact, which with mathematical necessity
-follows from the general disproportion between the average number of
-organic individuals and the numerical excess of their germs. But as
-Adaptation and Inheritance in the struggle for life are in continual
-interaction, it inevitably follows that _natural selection_, which
-everywhere influences and continually changes organic species, must, by
-making use of _divergence of character_, produce new species. Its
-influence is further especially favoured by the active and passive
-_migrations_ of organisms, which go on everywhere. If we give these
-circumstances due consideration, the continual and gradual modification
-or transmutation of organic species will appear as a biological process,
-which must, according to causal law, of _necessity_ follow from the
-actual nature of organisms and their mutual correlations.
-
-That even the _origin of man_ must be explained by this general organic
-process of transmutation, and that it is simply as well as naturally
-explained by it, has, I believe, been sufficiently proved in my last
-chapter but one. I cannot, however, avoid here once more directing
-attention to the inseparable connection between this so-called "theory
-of apes," or "pithecoid theory," and the whole Theory of Descent. If the
-latter is the greatest _inductive law_ of biology, then it of necessity
-follows that the former is its most important _deductive law_. They
-stand and fall together. As all depends upon a right understanding of
-this proposition, which in my opinion is very important, and which I
-have therefore several times brought before the reader, I may be allowed
-to explain it here by an example.
-
-In all mammals known to us the centre of the nervous system is the
-spinal marrow and the brain, and the centre of the vascular system is a
-quadrupal heart, consisting of two principal chambers and two
-ante-chambers. From this we draw the general inductive conclusion that
-all mammals, without exception, those extinct, together with all those
-living species as yet unknown to us, as well as the species which we
-have examined, possess a like organization, a like heart, brain, and
-spinal marrow. Now if, as still happens every year, there be discovered
-in any part of the earth a new species of mammal, a new species of
-marsupial, or a new species of deer, or a new species of ape, every
-zoologist knows with certainty at once, without having examined its
-inner structure, that this species must possess a quadruple heart, a
-brain and spinal marrow, like all other mammals. Not a single naturalist
-would ever think of supposing that the central nervous system of this
-new species of mammal could possibly consist of a ventral cord with an
-oesophageal collar as in the insects, or of scattered pairs of knots as
-in the molluscs, or that its heart could be many-chambered as in flies,
-or one-chambered as in the tunicates. This completely certain and safe
-conclusion, although it is not based upon any direct experience, is a
-_deductive conclusion_. In the same way, as I have shown in a previous
-chapter, Goethe, from the comparative anatomy of mammals, established
-the general inductive conclusion that they all possess a mid jawbone,
-and afterwards drew from it the special deductive conclusion that man,
-who in all other respects does not essentially differ from other
-mammals, must also possess a like mid jawbone. He maintained this
-conclusion without having actually seen the human mid jawbone, and only
-proved its existence subsequently by actual observation (vol. i. p. 84).
-
-The process of _induction_ is a logical system of forming conclusions
-_from the special to the general_, by which we advance from many
-individual experiences to a general law; _deduction_, on the other hand,
-draws a conclusion _from the general to the special_, from a general law
-of nature to an individual case. Thus the _Theory of Descent_ is,
-without doubt, a great _inductive law_, empirically based upon all the
-biological experience cited above; the pithecoid theory, on the other
-hand, which asserts that man has developed out of lower, and in the
-first place out of ape-like mammals, is a _deductive law_ inseparably
-connected with the general inductive law.
-
-The pedigree of the human race, the approximate outlines of which I gave
-in the last chapter but one, of course remains in detail (like all the
-pedigrees of animals and plants previously discussed) a more or less
-approximate general hypothesis. This however does not affect the
-application of the theory of descent to man. Here, as in all
-investigations on the derivation of organisms, one must clearly
-distinguish between the general _theory_ of descent and the special
-_hypotheses_ of descent. The general _theory_ of descent claims full and
-lasting value, because it is an inductive law, based upon all the whole
-series of biological phenomena and their inner causal connection. Every
-special _hypothesis_ of descent, on the other hand, has its special
-value determined by the existing condition of our biological knowledge,
-and by the extent of the objective empirical basis upon which we
-deductively establish this particular hypothesis. Hence, all the
-individual attempts to obtain a knowledge of the pedigree of any one
-group of organisms possesses but a temporary and conditional value, and
-any special hypothesis relating to it will become the more and more
-perfect the greater the advance we make in the comparative anatomy,
-ontogeny, and palæontology of the group in question. The more, however,
-we enter into genealogical details, and the further we trace the
-separate off-shoots and branches of the pedigree, the more uncertain and
-subjective becomes our special _hypothesis_ of descent on account of the
-incompleteness of our empirical basis. This however does no injury to
-the general _theory_ of descent, which remains as the indispensable
-foundation for really profound apprehension of biological phenomena.
-Accordingly, there can be no doubt that we can and must, with full
-assurance, regard the derivation of man--in the first place, from
-ape-like forms; farther back, from lower mammals, and thus continually
-farther back to lower stages of the vertebrata down to their lowest
-invertebrate roots, nay, even down to a simple plastid--as a general
-_theory_. On the other hand, the special tracing of the human pedigree,
-the closer definition of the animal forms known to us, which either
-actually belong to the ancestors of man, or at least stand in very close
-blood relationship to them, will always remain a more or less
-approximate _hypothesis_ of descent, all the more in danger of deviating
-from the real pedigree the nearer it endeavours to approach it by
-searching for the individual ancestral forms. This state of things
-results from the immense gaps in our palæontological knowledge, which
-can, under no circumstances, ever attain to even an approximate
-completeness.
-
-A thoughtful consideration of this important circumstance at once
-furnishes the answer to a question which is commonly raised in
-discussing this subject, namely, the question of scientific _proofs for
-the animal origin of the human race_. Not only the opponents of the
-Theory of Descent, but even many of its adherents who are wanting in the
-requisite philosophical culture, look too much for "signs" and for
-special empirical advances in the science of nature. They await the
-sudden discovery of a human race with tails, or of a talking species of
-ape, or of other living or fossil transition forms between man and the
-ape, which shall fill the already narrow chasm between the two, and thus
-empirically "prove" the derivation of man from apes. Such special
-manifestations, were they ever so convincing and conclusive, would not
-furnish the proof desired. Unthinking persons, or those unacquainted
-with the series of biological phenomena, would still be able to maintain
-the objections to those special testimonies which they now maintain
-against our theory.
-
-The absolute certainty of the Theory of Descent, even in its application
-to man, is built on a more solid foundation; and its true inner value
-can never be tested simply by reference to individual experience, but
-only by a philosophical comparison and estimation of the treasures of
-all our biological experiences. The inestimable importance of the Theory
-of Descent is surely based upon this, that the theory follows of
-necessity (as a general inductive law) from the comparative synthesis of
-all organic phenomena of nature, and more especially from the triple
-parallelism of comparative anatomy, of ontogeny, and phylogeny; and the
-pithecoid theory under all circumstances (apart from all special proofs)
-remains as a special deductive conclusion which must of necessity be
-drawn from the general inductive law of the Theory of Descent.
-
-In my opinion, all depends upon a right understanding of this
-_philosophical foundation of the Theory of Descent_ and of the
-_pithecoid theory_ which is inseparable from it. Many persons will
-probably admit this, and yet at the same time maintain that all this
-applies only to the _bodily_, not to the _mental_ development of man.
-Now, as we have hitherto been occupied only with the former, it is
-perhaps necessary here to cast a glance at the latter, in order to show
-that it is also subject to the great general law of development. In
-doing this it is above all necessary to recollect that body and mind can
-in fact never be considered as distinct, but rather that both sides of
-nature are inseparably connected, and stand in the closest interaction.
-As even Goethe has clearly expressed it--"matter can never exist and act
-without mind, and mind never without matter." The artificial discord
-between mind and body, between force and matter, which was maintained by
-the erroneous dualistic and teleological philosophy of past times has
-been disposed of by the advances of natural science, and especially by
-the theory of development, and can no longer exist in face of the
-prevailing mechanical and monistic philosophy of our day. How human
-nature, and its position in regard to the rest of the universe, is to be
-conceived of according to the modern view, has been minutely discussed
-by Radenhausen in his "Isis,"(33) which is excellent and well worth
-perusal.
-
-With regard to the origin of the human mind or the soul of man, we, in
-the first place, perceive that in every human individual it develops
-from the beginning, step by step and gradually, just like the body. In a
-newly born child we see that it possesses neither an independent
-consciousness, nor in fact clear ideas. These arise only gradually when,
-by means of sensuous experience, the phenomena of the outer world affect
-the central nervous system. But still the little child is wanting in all
-those differentiated emotions of the soul which the full-grown man
-acquires only by the long experience of years. From this graduated
-development of the human soul in every single individual we can, in
-accordance with the inner causal connection between ontogeny and
-phylogeny, directly infer the gradual development of the human soul in
-all mankind, and further, in the whole of the vertebrate tribe. In its
-inseparable connection with the body, the human soul or mind has also
-had to pass through all those gradual stages of development, all those
-various degrees of differentiation and perfecting, of which the
-hypothetical series of human ancestors sketched in a late chapter gives
-an approximate representation.
-
-It is true that this conception generally greatly offends most persons
-on their first becoming acquainted with the Theory of Development,
-because more than all others it most strongly contradicts the
-traditional and mythological ideas, and the prejudices which have been
-held sacred for thousands of years. But like all other functions of
-organisms, the human soul must necessarily have historically developed,
-and the comparative or empirical study of animal psychology clearly
-shows that this development can only be conceived of as a gradual
-evolution from the soul of vertebrate animals, as a gradual
-differentiation and perfecting which, in the course of many thousands of
-years, has led to the glorious triumph of the human mind over its lower
-animal ancestral stages. Here, as everywhere, the only way to arrive at
-a knowledge of natural truth is to compare kindred phenomena, and
-investigate their development. Hence we must above all, as we did in the
-examination of the bodily development, compare the highest animal
-phenomena on the one hand with the lowest animal phenomena, and on the
-other with the lowest human phenomena. The final result of this
-comparison is this--that _between the most highly developed animal
-souls, and the lowest developed human souls, there exists only a small
-quantitative, but no qualitative difference_, and that this difference
-is much less than the difference between the lowest and the highest
-human souls, or than the difference between the highest and the lowest
-animal souls.
-
-In order to be convinced of this important result, it is above all
-things necessary to study and compare the mental life of wild savages
-and of children.(32) At the lowest stage of human mental development are
-the Australians, some tribes of the Polynesians, and the Bushmen,
-Hottentots, and some of the Negro tribes. Language, the chief
-characteristic of genuine men, has with them remained at the lowest
-stage of development, and hence also their formation of ideas has
-remained at a low stage. Many of these wild tribes have not even a name
-for animal, plant, colour, and such most simple ideas, whereas they have
-a word for every single, striking _form_ of animal and plant, and for
-every single sound or colour. Thus even the most simple abstractions are
-wanting. In many of these languages there are numerals only for one,
-two, and three: no Australian language counts beyond four. Very many
-wild tribes can count no further than ten or twenty, whereas some very
-clever dogs have been made to count up to forty and even beyond sixty.
-And yet the faculty of appreciating number is the beginning of
-mathematics! Nothing, however, is perhaps more remarkable in this
-respect, than that some of the wildest tribes in southern Asia and
-eastern Africa have no trace whatever of the first foundations of all
-human civilization, of family life, and marriage. They live together in
-herds, like apes, generally climbing on trees and eating fruits; they do
-not know of fire, and use stones and clubs as weapons, just like the
-higher apes. All attempts to introduce civilization among these, and
-many of the other tribes of the lowest human species, have hitherto been
-of no avail; it is impossible to implant human culture where the
-requisite soil, namely, the perfecting of the brain, is wanting. Not one
-of these tribes has ever been ennobled by civilization; it rather
-accelerates their extinction. They have barely risen above the lowest
-stage of transition from man-like apes to ape-like men, a stage which
-the progenitors of the higher human species had already passed through
-thousands of years ago.(44)
-
-Now consider, on the other hand, the highest stages of development of
-mental life in the higher vertebrate animals, especially birds and
-mammals. If, as is usually done, we divide the different emotions of the
-soul into three principal groups--sensation, will, and thought--we shall
-find in regard to every one of them, that the most highly developed
-birds and mammals are on a level with the lowest human beings, or even
-decidedly surpass them. The _will_ is as distinctly and strongly
-developed in higher animals as in men of character. In both cases it is
-never actually free, but always determined by a causal chain of ideas.
-(Compare vol. i. p. 237.) In like manner, the different degrees of will,
-energy, and passion are as variously graduated in higher animals as in
-man. The _affections_ of the higher animals are not less tender and warm
-than those of man. The fidelity and devotion of the dog, the maternal
-love of the lioness, the conjugal love and connubial fidelity of doves
-and love-birds are proverbial, and might serve as examples to many men.
-If these virtues are to be called "instincts," then they deserve the
-same name in mankind. Lastly, with regard to _thought_, the comparative
-consideration of which doubtless presents the most difficulties, this
-much may with certainty be inferred--especially from an examination of
-the comparative psychology of cultivated domestic animals--that the
-processes of thinking, here follow the same laws as in ourselves.
-Experiences everywhere form the foundation of conceptions, and lead to
-the recognition of the connection between cause and effect. In all
-cases, as in man, it is the path of induction and deduction which leads
-to the formation of conclusions. It is evident that in all these
-respects the most highly developed animals stand much nearer to man than
-to the lower animals, although they are also connected with the latter
-by a chain of gradual and intermediate stages. In Wundt's excellent
-"Lectures on the Human and Animal Soul,"(46) there are a number of
-proofs of this.
-
-Now, if instituting comparisons in both directions, we place the lowest
-and most ape-like men (the Austral Negroes, Bushmen, and Andamans,
-etc.), on the one hand, together with the most highly developed animals,
-for instance, with apes, dogs, and elephants, and on the other hand,
-with the most highly developed men--Aristotle, Newton, Spinoza, Kant,
-Lamarck, or Goethe--we can then no longer consider the assertion, that
-the mental life of the higher mammals has gradually developed up to that
-of man, as in any way exaggerated. If one must draw a sharp boundary
-between them, it has to be drawn between the most highly developed and
-civilized man on the one hand, and the rudest savages on the other, and
-the latter have to be classed with the animals. This is, in fact, the
-opinion of many travellers, who have long watched the lowest human races
-in their native countries. Thus, for example, a great English traveller,
-who lived for a considerable time on the west coast of Africa, says: "I
-consider the negro to be a lower species of man, and cannot make up my
-mind to look upon him as 'a man and a brother,' for the gorilla would
-then also have to be admitted into the family." Even many Christian
-missionaries, who, after long years of fruitless endeavours to civilize
-these lowest races, have abandoned the attempt, express the same harsh
-judgment, and maintain that it would be easier to train the most
-intelligent domestic animals to a moral and civilized life, than these
-unreasoning brute-like men. For instance, the able Austrian missionary
-Morlang, who tried for many years without the slightest success to
-civilize the ape-like negro tribes on the Upper Nile, expressly says:
-"that any mission to such savages is absolutely useless. They stand far
-below unreasoning animals; the latter at least show signs of affection
-towards those who are kind towards them, whereas these brutal natives
-are utterly incapable of any feeling of gratitude."
-
-Now, it clearly follows from these and other testimonies, that the
-mental differences between the lowest men and the animals are less than
-those between the lowest and the highest men; and if, together with
-this, we take into consideration the fact that in every single human
-child mental life develops slowly, gradually, and step by step, from the
-lowest condition of animal unconsciousness, need we still feel offended
-when told that the mind of the whole human race has in like manner gone
-through a process of slow, gradual, and historical development? Can we
-find it "degrading" to the human soul that, by a long and slow process
-of differentiation and perfecting, it has very gradually developed out
-of the soul of vertebrate animals? I freely acknowledge that this
-objection, which is at present raised by many against the pithecoid
-theory, is quite incomprehensible to me. On this point Bernhard Cotta,
-in his excellent "Geologie der Gegenwart," very justly remarks: "Our
-ancestors may be a great honour to us; but it is much better if we are
-an honour to them!"(31)
-
-Our Theory of Development explains the origin of man and the course of
-his historical development in the only natural manner. We see in his
-gradually ascensive development out of the lower vertebrata, the
-greatest triumph of humanity over the whole of the rest of Nature. We
-are proud of having so immensely outstripped our lower animal ancestors,
-and derive from it the consoling assurance that in future also, mankind,
-as a whole, will follow the glorious career of progressive development,
-and attain a still higher degree of mental perfection. When viewed in
-this light, the Theory of Descent as applied to man opens up the most
-encouraging prospects for the future, and frees us from all those
-anxious fears which have been the scarecrows of our opponents.
-
-We can even now foresee with certainty that the complete victory of our
-Theory of Development will bear immensely rich fruits--fruits which have
-no equal in the whole history of the civilization of mankind. Its first
-and most direct result--the complete reform of _Biology_--will
-necessarily be followed by a still more important and fruitful reform of
-_Anthropology_. From this new theory of man there will be developed a
-new _philosophy_, not like most of the airy systems of metaphysical
-speculation hitherto prevalent, but one founded upon the solid ground of
-Comparative Zoology. A beginning of this has already been made by the
-great English philosopher Herbert Spencer.(45) Just as this new monistic
-philosophy first opens up to us a true understanding of the real
-universe, so its application to practical human life must open up a new
-road towards moral perfection. By its aid we shall at last begin to
-raise ourselves out of the state of social barbarism in which,
-notwithstanding the much vaunted civilization of our century, we are
-still plunged. For, unfortunately, it is only too true, as Alfred
-Wallace remarks with regard to this, at the end of his book of travels:
-"Compared with our wondrous progress in physical science and its
-practical applications, our system of government, of administering
-justice, of national education, and our whole social and moral
-organisation remains in a state of barbarism."
-
-This social and moral barbarism we shall never overcome by the
-artificial and perverse training, the one-sided and defective teaching,
-the inner untruth and the external tinsel, of our present state of
-civilization. It is above all things necessary to make a complete and
-honest return to Nature and to natural relations. This return, however,
-will only become possible when man sees and understands his true "place
-in nature." He will then, as Fritz Ratzel has excellently remarked,(47)
-"no longer consider himself an _exception_ to natural laws, but begin to
-seek for what is lawful in his own actions and thoughts, and endeavour
-to lead a life _according_ to natural laws." He will come to arrange his
-life with his fellow-creatures--that is, the family and the state--not
-according to the laws of distant centuries, but according to the
-rational principles deduced from knowledge of nature. Politics, morals,
-and the principles of justice, which are still drawn from all possible
-sources, will have to be formed in accordance with natural laws only. An
-_existence worthy of man_, which has been talked of for thousands of
-years, will at length become a reality.
-
-The highest function of the human mind is perfect knowledge, fully
-developed consciousness, and the moral activity arising from it. "Know
-thyself!" was the cry of the philosophers of antiquity to their
-fellow-men who were striving to ennoble themselves. "Know thyself!" is
-the cry of the Theory of Development, not merely to the individual, but
-to all mankind. And whilst increased knowledge of self becomes, in the
-case of every individual man, a strong force urging to an increased
-attention to conduct, mankind as a whole will be led to a higher path of
-moral perfection by the knowledge of its true origin and its actual
-position in Nature. The simple religion of Nature, which grows from a
-true knowledge of Her, and of Her inexhaustible store of revelations,
-will in future ennoble and perfect the development of mankind far beyond
-that degree which can possibly be attained under the influence of the
-multifarious religions of the churches of the various
-nations,--religions resting on a blind belief in the vague secrets and
-mythical revelations of a sacerdotal caste. Future centuries will
-celebrate our age, which was occupied with laying the foundations of the
-Doctrine of Descent, as the new era in which began a period of human
-development, rich in blessings,--a period which was characterized by the
-victory of free inquiry over the despotism of authority, and by the
-powerful ennobling influence of the Monistic Philosophy.
-
-
-  FOOTNOTES:
-
-  [1] With the exception of a single specimen of the bones of a foot,
-  preserved in the cabinet of Amherst College.--E. R. L.
-
-  [2] The primary stock of the Coniferæ divided into two branches at an
-  early period, into the Araucariæ on the one hand, and the Taxaceæ, or
-  yew-trees, on the other. The majority of recent Coniferæ are derived
-  from the former. Out of the latter the third class of the
-  Gymnosperms--the Meningos, or Gnetaceæ--were developed. This small but
-  very interesting class contains only three different genera--Gnetum,
-  Welwitschia, and Ephedra; it is, however, of great importance, as it
-  forms the transition group from the Coniferæ to the Angiosperms, and
-  more especially to the Dicotyledons.
-
-  [3] "Ueber ein Aequivalent der takonischen Schiefer Nordamerikas in
-  Deutschland."
-
-  [4] The English word "Insects" might with advantage be used in the
-  Linnæan sense for the whole group of Arthropods. In this case the
-  Hexapod Insects might be spoken of as the Flies.--E. R. L.
-
-  [5] Weisbach: "Novara-Reise," Anthropholog. Theil.
-
-  [6]        Müsset im Naturbetrachten
-             Immer Eins wie Alles achten.
-             Nichts ist drinnen, Nichts ist drauszen,
-             Denn was innen, das ist auszen.
-
-  [7]        Natur hat weder Kern noch Schale,
-             Alles ist sie mit einem Male.
-
-
-
-
-LIST OF THE WORKS REFERRED TO IN THE TEXT BY FIGURES, THUS--(1),
-
-_The study of which is recommended to the Reader._
-
-
-1. _Charles Darwin_, On the Origin of Species by means of Natural
-Selection; or, the Preservation of Favoured Races in the Struggle for
-Life. London, 1859. 5th Edition, 1869.
-
-2. _Jean Lamarck_, Philosophie Zoologique, ou Exposition des
-Considérations relatives à l'histoire naturelle des animaux; à la
-diversité de leur organisation et des facultés, qu'ils en obtiennent;
-aux causes physiques, qui maintiennent en eux la vie et donnent lieu aux
-mouvemens, qu'ils exécutent; enfin, à celles qui produisent, les unes le
-sentiment, et les autres l'intelligence de ceux qui en sont doués. 2
-Tomes. Paris, 1809.
-
-3. _Wolfgang Goethe_, Zur Morphologie: Bildung und Umbildung organischer
-Naturen. Die Metamorphose der Pflanzen, 1790. Osteologie, 1786. Vorträge
-über die drei ersten Capitel des Entwurfs einer allgemeinen Einleitung
-in die vergleichende Anatomie, ausgehend von der Osteologie, 1786. Zur
-Naturwissenschaft im Allgemeinen, 1780-1832.
-
-(Wolfgang Goethe, Contributions to Morphology: Formation and
-Transformation of Organic Natures. The Metamorphosis of Plants, 1790.
-Osteology, 1786. Lectures on the first three chapters of an Attempt at a
-General Introduction to Comparative Anatomy, beginning with Osteology,
-1786. Contributions to the Science of Nature in general, 1780-1832.)
-
-4. _Ernst Haeckel_, Generelle Morphologie der Organismen: Allgemeine
-Grundzüge der organischen Formenwissenschaft, mechanisch begründet durch
-die von Charles Darwin reformirte Descendenz-theorie. I. Band,
-Allgemeine Anatomie der Organismen, oder Wissenschaft von den
-entwickelten organischen Formen. II. Band, Allgemeine
-Entwickelungsgeschichte der Organismen, oder Wissenschaft von den
-entstehenden organischen Formen. Berlin, 1866.
-
-(Ernst Haeckel, General Morphology of Organisms; General Outlines of the
-Science of Organic Forms based on Mechanical Principles through the
-Theory of Descent as reformed by Charles Darwin. Vol. I., General
-Anatomy of Organisms; or, the Science of Fully Developed Organic Forms.
-Vol. II., General History of the Development of Organisms; or, the
-Science of Organic Forms in their Origin. Berlin, 1866.)
-
-5. _Louis Agassiz_, An Essay on Classification. Contributions to the
-Natural History of the United States. Boston. Vol. I., 1857.
-
-6. _August Schleicher_, Die Darwin'sche Theorie und die
-Sprachwissenschaft. Weimar, 1863.
-
-(August Schleicher, Darwin's Theory and the Science of Language. Weimar,
-1863.)
-
-7. _M. J. Schleiden_, Grundzüge der wissenschaftlichen Botanik (die
-Botanik als inductive Wissenschaft). 2 Bände. Leipzig, 1849.
-
-(M. J. Schleiden, Principles of Scientific Botany (Botany as an
-Inductive Science). 2 Vols. Leipzig, 1849. Translated by Edwin
-Lankester, M.D., F.R.S. London, 1849.)
-
-8. _Franz Unger_, Versuch einer Geschichte der Pflanzenwelt. Wien, 1852.
-
-(Franz Unger, Essay on the History of the Vegetable Kingdom. Vienna,
-1852.)
-
-9. _Victor Carus_, System der thierischen Morphologie. Leipzig, 1853.
-
-(Victor Carus, System of Animal Morphology. Leipzig, 1853.)
-
-10. _Louis Büchner_, Kraft und Stoff. Empirisch-naturphilosophische
-Studien in allgemein verständlicher Darstellung, Frankfort, 1855, 3
-Auflage. 1867, 9 Auflage.
-
-(Louis Büchner, Force and Matter. Studies in the Empirical Philosophy of
-Nature, treated popularly. Frankfort, 1855, 3rd Edition. 1867, 9th
-Edition.)
-
-11. _Charles Lyell_, Principles of Geology. London, 1830. 10th Edition,
-1868.
-
-12. _Albert Lange_, Geschichte des Materialismus und Kritik seiner
-Bedeutung in der Gegenwart. Iserlohn, 1866.
-
-(Albert Lange, History of Materialism, and a Criticism of its Importance
-at the Present Time. Iserlohn, 1866.)
-
-13. _Charles Darwin_, Voyage of the _Beagle_. London.
-
-14. _Charles Darwin_, The Variation of Animals and Plants under
-Domestication. 2 Vols. London, 1868.
-
-15. _Ernst Haeckel_, Studien über Moneren und andere Protisten, nebst
-einer Rede über Entwickelungsgang und Aufgabe der Zoologie. Mit 6
-Kupfertafeln. Leipzig, 1870.
-
-(Ernst Haeckel, Studies on the Monera and other Protista, together with
-a Discourse on the Evolution and the Problems of Zoology. With 6
-Copper-plates. Leipzig, 1870.)
-
-16. _Fritz Müller_, Für Darwin. Leipzig, 1864.
-
-(Fritz Müller, For Darwin. Translated by W. S. Dallas. London, Murray.)
-
-17. _Thomas Huxley_, On our Knowledge of the Causes of the Phenomena of
-Organic Nature. Six Popular Lectures. London, Hardwicke, 1862.
-
-18. _H. G. Brönn_, Morphologische Studien über die Gestaltungsgesetze
-der Naturkörper überhaupt, und der Organischen insbesondere. Leipzig und
-Heidelberg, 1858.
-
-(H. G. Brönn, Morphological Studies on the Laws of Form of Natural
-Bodies in General, and of Organic Bodies in Particular. Leipzig and
-Heidelberg, 1858.)
-
-19. _H. G. Brönn_, Untersuchungen über die Entwickelungsgesetze der
-organischen Welt während der Bildungszeit unserer Erdoberfläche.
-Stuttgart, 1858.
-
-(H. G. Brönn, Investigations on the Laws of Development of the Organic
-World during the Time of the Formation of the Earth's Crust. Stuttgart,
-1858.)
-
-20. _Carl Ernst Bär_, Ueber Entwickelungsgeschichte der Thiere.
-Beobachtung und Reflexion. 2 Bände. 1828.
-
-(Carl Ernst Bär, On the History of the Development of Animals.
-Observation and Reflection. 2 Vols. 1828.)
-
-21. _Carl Gegenbaur_, Grundzüge der vergleichenden Anatomie. Leipzig,
-1859. 2 (Umgearbeitete) Auflage, 1870.
-
-(Carl Gegenbaur, Outlines of Comparative Anatomy. Leipzig, 1859. 2nd
-(Revised) Edition, 1870.)
-
-22. _Immanuel Kant_, Allgemeine Naturgeschichte und Theorie des Himmels,
-oder Versuch von der Verfassung und dem mechanischen Ursprunge des
-ganzen Weltgebäudes nach Newton'schen Grundsätzen abgehandelt.
-Königsberg, 1755.
-
-(Immanuel Kant, General History of Nature and Theory of the Heavens; or,
-Essay on the Constitution and the Mechanical Origin of the whole
-Universe treated according to Newton's Principles. Königsberg, 1755.)
-
-23. _Ernst Haeckel_, Die Radiolarien. Eine Monographie. Mit einem Atlas
-von 35 Kupfertafeln. Berlin, 1862.
-
-(Ernst Haeckel, The Radiolaria. A Monograph, with Atlas containing 35
-Copper-plates. Berlin, 1862.)
-
-24. _August Weismann_, Ueber den Einflusz der Isolirung auf die
-Artbildung. Leipzig, 1872.
-
-(August Weismann, On the Influence of Isolation on the Formation of
-Species. Leipzig, 1872.)
-
-25. _Ernst Haeckel_, Ueber die Enstehung und den Stammbaum des
-Menschengeschlechts. Zwei Vorträge in der Sammlung gemeinverständlicher
-wissenschaftlicher Vorträge, herausgegeben von Virchow und Holtzendorff.
-Berlin, 1868. 2 Auflage, 1870.
-
-(Ernst Haeckel, On the Origin and the Pedigree of the Human Race. Two
-Lectures in the Collection of Popular Scientific Lectures, edited by
-Virchow and Holtzendorff. Berlin, 1868. 2nd Edition, 1870.)
-
-26. _Thomas Huxley_, Evidences as to Man's Place in Nature. Three Parts:
-1. On the Natural History of the Man-like Apes. 2. On the Relations of
-Man to the Lower Animals. 3. On some Fossil Remains of Man. London,
-Williams & Norgate.
-
-27. _Carl Vogt_, Vorlesungen über den Menschen, seine Stellung in der
-Schöpfung und in der Geschichte der Erde. 2 Bände. Giessen, 1863.
-
-(Carl Vogt, Lectures on Man, his Place in Creation and in the History of
-the Earth. 2 Vols. Giessen, 1863.)
-
-28. _Friedrich Rolle_, Der Mensch, seine Abstammung und Gesittung im
-Lichte der Darwin'schen Lehre von der Art-Entstehung, und auf Grund der
-neueren geologischen Entdeckungen dargestellt. Frankfurt-a-M., 1866.
-
-(Friedrich Rolle, Man, his Derivation and Civilization, in the Light of
-Darwin's Theory of the Origin of Species, based on Recent Geological
-Discoveries. Frankfort-a-M., 1866.)
-
-29. _Eduard Reich_, Die allgemeine Naturlehre des Menschen. Giessen,
-1865.
-
-(Eduard Reich, The General Natural History of Man. Giessen, 1865.)
-
-30. _Charles Lyell_, The Antiquity of Man. London, Murray.
-
-31. _Bernhard Cotta_, Die Geologie der Gegenwart. Leipzig, 1866.
-
-(Bernhard Cotta, The Geology of the Present Day.)
-
-32. _Karl Zittel_, Aus der Urzeit. Bilder aus der Schöpfungsgeschichte.
-München, 1871.
-
-(Karl Zittel, Primæval Times. Pictures from the History of Creation.
-Munich, 1871.)
-
-33. _C. Radenhausen_, Isis. Der Mensch und die Welt. 4 Bände. Hamburg,
-1863. 2 Auflage, 1871.
-
-(C. Radenhausen, Isis. Man and the Universe. 4 Vols. Hamburg, 1863. 2nd
-Edition, 1871.)
-
-34. _August Schleicher_, Ueber der Bedeutung der Sprache für die
-Naturgeschichte des Menschen. Weimar, 1865.
-
-(August Schleicher, On the Importance of Language to the Natural History
-of Man. Weimar, 1865).
-
-35. _Wilhelm Bleek_, Ueber den Ursprung der Sprache. Herausgegeben mit
-einem Vorwort von Ernst Haeckel. Weimar, 1868.
-
-(Wilhelm Bleek, On the Origin of Language. Edited and with a Preface by
-Ernst Haeckel. Weimar, 1868.)
-
-36. _Alfred Russel Wallace_, The Malayan Archipelago. London, Macmillan.
-
-37. _Ernst Haeckel_, Ueber Arbeitstheilung in Natur- und Menschenleben.
-Sammlung gemeinverständlicher wissenschaftlicher Vorträge, herausgegeben
-von Virchow und Holtzendorff. 4 Serie. 1869. Heft 78.
-
-(Ernst Haeckel, On Differentiation in Nature and in Human Life. A
-Collection of Popular Scientific Lectures, edited by Virchow and
-Holtzendorff. 4th Series. 1869. No. 78.)
-
-38. _Hermann Helmholtz_, Populäre wissenschaftliche Vorträge.
-Braunschweig, 1871.
-
-(Hermann Helmholtz, Popular Scientific Lectures. Brunswick, 1871.)
-
-39. _Alexander Humboldt_, Ansichten der Natur. Stuttgart, 1826.
-
-(Alexander Humboldt, Views of Nature. Stuttgart, 1826.)
-
-40. _Moritz Wagner_, Die Darwin'sche Theorie und das Migrationsgesetz
-der Organismen. Leipzig, 1868.
-
-(Moritz Wagner, Darwin's Theory and the Law of the Migration of
-Organisms. Leipzig, 1868.)
-
-41. _Rudolf Virchow_, Vier Reden über Leben und Kranksein. Berlin, 1862.
-
-(Rudolf Virchow, Four Discourses on Life and Disease. Berlin, 1862.)
-
-42. _Friedrich Müller_, Ethnographie (Reise der österreichischen
-Fregatte Novara. Anthropologischer Theil. 3 Abtheilung). Wien, 1868.
-
-(Friedrich Müller, Ethnography (Voyage of the Austrian Frigate _Novara_.
-Anthropological Part. 3rd Part). Vienna, 1868.)
-
-43. _Ludwig Büchner_, Die Stellung des Menschen in der Natur, in
-Vergangenheit, Gegenwart und Zukunft. Leipzig, 1870.
-
-(Ludwig Büchner, Man's Place in Nature in the Past, the Present, and the
-Future. Leipzig, 1870.)
-
-44. _John Lubbock_, Prehistoric Times. London, 1867.
-
-45. _Herbert Spencer_, A System of Philosophy. (1. First Principles. 2.
-Principles of Biology. 3. Principles of Psychology, etc.) London, 1867.
-2nd Edition.
-
-46. _Wilhelm Wundt_, Vorlesungen über die Menschen- und Thierseele.
-Leipzig, 1863.
-
-(Wilhelm Wundt, Lectures on the Human and Animal Soul. Leipzig, 1863.)
-
-47. _Fritz Ratzel_, Sein und Werden der organischen Welt. Eine populäre
-Schöpfungsgeschichte. Leipzig, 1869.
-
-(Fritz Ratzel, Nature and Origin of the Organic World. A Popular History
-of Creation. Leipzig, 1869.)
-
-48. _Charles Darwin_, The Descent of Man, and Selection in Relation to
-Sex. 2 Vols. London, 1871.
-
-
-
-
-APPENDIX.
-
-EXPLANATION OF THE PLATES.
-
-
-  PLATE FACING TITLE-PAGE.
-
-_Developmental History of a Calcareous Sponge_ (Olynthus). Compare vol.
-ii. p. 140. The egg of the Olynthus (Fig. 9), which represents the
-common ancestral form of all Calcareous Sponges, is a simple cell (Fig.
-1). From this there arises, by repeated division (Fig. 2), a globular,
-mulberry-like heap of numerous equi-formal cells (Morula, Fig. 3; vol.
-ii. p. 125.) As the result of the change of these cells into an outer
-series of clear ciliated cells (Exoderm) and an inner series of dark,
-non-ciliated cells (Entoderm), the ciliated larva, or Planula, makes its
-appearance. This is oval in shape, and forms a cavity in its centre
-(gastric cavity, or primitive stomach, Fig. 6 _g_, with an opening
-(mouth-opening, or primitive mouth, Fig. 6 _o_); the wall of the gastric
-cavity consists of two layers of cells, or germ-layers, the outer
-ciliated Exoderm (_e_) and the inner non-ciliated Entoderm (_i_). Thus
-arises the exceedingly important stomach-larva, or Gastrula, which
-reappears in the most different tribes of animals as a common larval
-form (Fig. 5, seen from the surface; Fig. 6, in long section. Compare,
-vol. ii. pp. 126 and 281). After the Gastrula has swum about for some
-time in the sea, it fastens itself securely to the sea-bottom, loses its
-outer vibratile processes, or cilia, and changes into the Ascula (Fig.
-7, seen from the surface; Fig. 8, in long section; letters as in Fig.
-6). This Ascula is the recapitulative form, according to the biogenetic
-fundamental law, the common ancestor of all Zoophytes, namely, the
-Protascus (vol. ii. pp. 129, 133). By the development of pores in the
-wall of the stomach and of three-rayed calcareous spicules, the Ascula
-changes into the Olynthus (Fig. 9.) In Fig. 9 a piece is cut out from
-the stomach-wall of the Olynthus in order to show the inside of the
-stomachal cavity, and the eggs which are forming on the surface (_g_).
-From the Olynthus the most various forms of Calcareous Sponges can
-develop. One of the most remarkable is the Ascometra (Fig. 10), a stock
-or colony from which different species, and in fact different generic
-forms, grow (on the left Olynthus, in the middle Nardorus, on the right
-Soleniscus, etc., etc.). Further details as to these most interesting
-forms, and their high importance for the Theory of Descent, may be found
-in my "Monograph of the Calcareous Sponges" (1872), especially in the
-first volume. (Compare vol. ii. pp. 160, 167).
-
-
-  PLATE I. (_Between pages 184 and 185, Vol. I._)
-
-_History of the Life of the most Simple Organism_, a Moneron (Protomyxa
-aurantiaca). Compare vol. i. p. 184, and vol. ii. p. 53. The plate is a
-smaller copy of the drawing in my "Monographie der Moneren" (Biologische
-Studien, 1 Heft, 1870; Taf. 1), of the developmental history of the
-Protomyxa aurantiaca; I have there also given a detailed description of
-this remarkable Moneron (pp. 11-30). I discovered this most simple
-organism in January, 1867, during a stay in Lanzarote, one of the Canary
-Islands; and moreover I found it either adhering to, or creeping about
-on the white calcareous shells of a small Cephalopod (vol. ii. p. 162),
-the Spirula Peronii, which float there in masses on the surface of the
-ocean, or are thrown up on the shore. The Protomyxa aurantiaca is
-distinguished from the other Monera by the beautiful and bright
-orange-red colour of its perfectly simple body, which consists merely of
-primæval slime, or protoplasm. The fully developed Moneron is
-represented in Figs. 11 and 12, very much enlarged. When it is hungry
-(Fig. 11), there radiate from the surface of the globular corpuscule of
-plasm, quantities of tree-shaped, branching and mobile threads
-(pseudo-feet, or pseudopodia), which do not become retiformly
-connected. When, however, the Moneron eats (Fig. 12), the mucous threads
-become variously connected, form net-works and enclose the extraneous
-corpuscule which serves as food, which the threads afterwards draw into
-the interior of the Protomyxa. Thus in Fig. 12 (above on the right), a
-silicious and ciliated Whip-swimmer (Peridinium, vol. ii. pp. 51, 57),
-has just been caught by the extended mucous filaments, and has been
-drawn into the interior of the mucous globule, in which there already
-are several half digested silicious infusoria (Tintinoida), and Diatomeæ
-(Isthmia). Now, when the Protomyxa has eaten and grown sufficiently, it
-draws in all its mucous filaments (Fig. 15), and contracts into the form
-of a globule (Fig. 16 and Fig. 1). In this state of repose the globule
-secretes a simple gelatinous covering (Fig. 2), and after a time
-subdivides into a large number of small mucous globules (Fig. 3). These
-soon commence to move, become pear-shaped (Fig. 4), break through the
-common covering (Fig. 5), and then swim about freely in the ocean by
-means of a delicate whip-shaped process, like the Flagellata (vol. ii.
-p. 57, Fig. 11). When they meet a Spirula shell, or any other suitable
-object, they adhere to it, draw in their whip, and creep slowly about on
-it by means of form-changing processes (Figs. 6, 7, 8), like Protamoebæ
-(vol. i. p. 186, vol. ii. p. 52). These small mucous corpuscules take
-food (Figs. 9, 10), and attain their full grown form (Figs. 11, 12),
-either by simple growth or by several of them fusing to form a larger
-protoplasmic mass (Plasmodium, Figs. 13, 14).
-
-
-  PLATES II. AND III. (_Between pages 294 and 295, Vol. I._)
-
-_Germs or Embryos of four different Vertebrate Animals_, namely,
-Tortoise (_A_ and _E_), Hen (_B_ and _F_), Dog (_C_ and _G_), and Man
-(_D_ and _H_). Figs. _A_, _D_, an early stage of development; Figs. _E_,
-_H_, a later stage. All the eight embryos are represented as seen from
-the right side, the curved back turned to the left. Figs. _A_ and _B_
-are seven times enlarged, Figs. _C_ and _D_ five times, Figs. _E_ and
-_H_ four times. Plate II. exhibits the very close blood relationship
-between birds and reptiles; Plate III. that between man and the other
-mammals.
-
-
-  PLATE IV. (_Between pages 34 and 35, Vol. II._)
-
-_The Hand, or Fore Foot, of nine different Mammals._ This plate is
-intended to show the importance of Comparative Anatomy to Phylogeny, in
-as much as it proves how the internal skeleton of the limbs is
-continually preserved by _inheritance_, although the external form is
-extremely changed by _adaptation_. The bones of the skeleton of the hand
-are drawn in white lines on the brown flesh and skin which surrounds
-them. All the nine hands are represented in the same position, namely
-the wrist (where the arm would be joined to it) is placed above, whilst
-the ends of the fingers or toes are turned downwards. The thumb, or the
-first (large) fore-toe is on the left in every figure; the little
-finger, or fifth toe is to the right at the edge of the hand. Each hand
-consists of three parts, namely (i.) the _wrist_ (carpus), composed of
-two cross rows of short bones (at the upper side of the hand); (ii.) the
-_mid-hand_ (metacarpus), composed of five long and strong bones (marked
-in the centre of the hand by the numbers 1-5); and (iii.) the five
-_fingers_, or _fore toes_ (digiti), every one of which again consists of
-several (mostly from two to three), _toe-pieces_, or _phalanges_. The
-hand of _man_ (Fig. 1), in regard to its entire formation, stands
-midway between that of the two large human apes, namely, that of the
-_gorilla_ (Fig. 2), and that of the _orang_ (Fig. 3). The fore paw of
-the _dog_ (Fig. 4), is more different, and the hand or breast fin of the
-_seal_ (Fig. 5) still more so. The adaptation of the hand to the
-movement of swimming, and its transformation into a fin for steering, is
-still more complete in the _dolphin_ (Ziphius, Fig. 6). The extended
-fingers and bones of the central hand here have remained short and
-strong in the swimming membrane, but they have become extremely long and
-thin in the _bat_ (Fig. 7), where the hand has developed into a wing.
-The extreme opposite of the latter formation is the hand of the _mole_
-(Fig. 8), which has acquired a powerful spade-like form for digging,
-with fingers which have become extremely short and thick. What is far
-more like the human hand than these latter forms, is the fore paw of the
-lowest and most imperfect of all mammals, the Australian _beaked animal_
-(Ornithorhynchus, Fig. 9), which in its whole structure stands nearer to
-the common, extinct, primary form of mammalia, than any known species.
-Hence man differs less in the formation of the hand from this common
-primary form than from the bat, mole, dolphin, seal, and many other
-mammals.
-
-
-  PLATE V. (_Between pages 84 and 85, Vol. II._)
-
-_Monophyletic, or One-rooted Pedigree of the Vegetable Kingdom_,
-representing the hypothesis of the common derivation of all plants, and
-the historical development of the different groups of plants during the
-palæontological periods of the earth's history. The horizontal lines
-denote the different smaller and larger periods of the organic history
-of the earth (which are spoken of in vol. ii. p. 14), and during which
-the strata containing fossils were deposited. The vertical lines
-separate the different main-classes and classes of the vegetable kingdom
-from one another. The arboriform and branching lines indicate, in an
-approximate manner, by their greater or less number and thickness, the
-greater or less degree of development, differentiation, and perfecting
-which each class probably attained in each geological period. (Compare
-vol. ii. pp. 82, 83.)
-
-
-  PLATE VI. (_Between pages 130 and 131, Vol. II._)
-
-_Monophyletic, or One-rooted Pedigree of the Animal Kingdom_,
-representing the _historical growth of the six animal tribes_ during the
-palæontological periods of the organic history of the earth. The
-horizontal lines _g h_, _i k_, _l m_, and _n o_ divide the five large
-periods of the organic history of the earth one from another. The field
-_g a b h_ comprises the archilithic, the field _i g h k_, the
-palæolithic, the field _l i k m_ the mesolithic, and the field _n l o m_
-the cenolithic period. The short, anthropolithic period is indicated
-by the line _n o_. (Compare vol. ii. p. 14.) The height of the separate
-fields corresponds with the relative length of the periods indicated by
-them, as they may approximately be estimated from the relative thickness
-of the neptunic strata deposited between them. (Compare vol. ii. p. 22.)
-The archilithic and primordial period alone, during which the
-Laurentian, Cambrian, and Silurian strata were deposited, was probably
-considerably longer than the four subsequent periods taken together.
-(Compare vol. ii. pp. 10, 20.) In all probability the two tribes of
-worms and Zoophytes attained their full development during the
-mid-primordial period (in the Cambrian system); the star-fishes and
-molluscs probably somewhat later (in the Silurian system); whereas the
-articulata and vertebrata are still increasing in variety and
-perfection.
-
-
-  PLATE VII. (_Between pages 146 and 147, Vol. II._)
-
-_Group of Animal-Trees_ (_Zoophytes, or Coelenterata_) _in the
-Mediterranean_. On the upper half of the plate is a swarm of swimming
-medusæ and ctenophora; on the lower half a few bunches of corals and
-hydroid polyps adhering to the bottom of the sea. (Compare the system of
-Zoophytes, vol. ii. p. 132, and on the opposite page their pedigree.)
-Among the adhering Zoophytes at the bottom of the ocean there is, below
-on the right hand, a large coral-colony (1), which is closely akin to
-the red precious coral (Eucorallium), and like the latter belongs to the
-group of corals with eight rays (Octocoralla Gorgonida); the single
-individuals (or persons) of the branching stock have the form of a star
-with eight rays, consisting of eight tentacles, which surround the
-mouth. (Octocoralla, vol. ii. p. 143.) Directly below and in front of it
-(quite below on the right), is a small bush of hydroid polyps (2),
-belonging to the group of bell-polyps, or Campanulariæ (vol. ii. p.
-146). A larger stock of hydroid polyps (3), belonging to the group of
-tube-polyps, or Tubullariæ, rises, to the left, on the opposite side,
-with its long thin branches. At its base is spread a stock of silicious
-sponges (Halichondria) (4), with short, finger-shaped branches (vol.
-ii. p. 139). Behind it, below on the left (5), is a very large marine
-rose (Actinia), a single individual from the class of six-rayed corals
-(Hexacoralla, vol. ii. p. 143). Its low, cylindrical body has a crown of
-very numerous and large leaf-shaped tentacles. Below, in the centre of
-the ground (6), is a sea-anemone (Cereanthus) from the group of
-fourfold corals (Tetracoralla). Lastly, on a small hill on the bottom
-of the sea, there rises, on the right above the corals (1) a cup-polyp
-(Lucernaria), as the representative of the stalked-jellies.
-(Podactinaria, or Calycozoa, vol. ii. p. 144.) Its cup-shaped, stalked
-body (7) has eight globular clusters of small, knotted tentacles on its
-rim.
-
-Among the _swimming Zoophytes_ which occupy the upper half of Plate
-VII., the hydromedusæ are especially remarkable, on account of their
-alteration of generation. (Compare vol. i. p. 206.) Directly above the
-Lucernaria (7) floats a small tiara jelly (Oceania), whose bell-shaped
-body has a process like a dome, the form of a papal tiara (8). From the
-opening of the bell there hangs a wreath of very fine and long
-tentacles. This Oceania is the offspring of a tube-polyp, resembling the
-adhering Tubularia below on the left (3). Beside this latter, on the
-left, swims a large but very delicate hair-jelly (Æquorea). Its
-disc-shaped, slightly arched body is just drawing itself together, and
-pressing water out of the cavity of the cup lying below (9). The
-numerous, long, and fine hair-like tentacles which hang down from the
-rim of the cup are drawn by the ejected water into a conical bunch,
-which towards the centre turns upwards like a collar, and is thrown into
-folds. Above, in the middle of the cavity of the cup, hangs the stomach,
-the mouth of which is surrounded by four lobes. This Æquorea is derived
-from a small bell-polyp, resembling the Campanularia (2). The small,
-slightly arched cap-jelly (Eucope), swimming above in the centre (10),
-is likewise derived from a similar bell-polyp. In these three last cases
-(8, 9, 10), as in the majority of the hydromedusæ, the alternation of
-generation consists in the freely swimming medusa (8, 9, 10), arising by
-the formation of buds (therefore by non-sexual generation, vol. i. p.
-192), from adhering hydroid polyps (2, 3). These latter, however,
-originate out of the fructified eggs of the medusæ (therefore by sexual
-generation, vol. i. p. 195). Hence the non-sexual, adhering generation
-of polyps (I., III., V., etc.) regularly alternates with the sexual,
-freely swimming generation of medusæ (II., IV., VI., etc.). This
-alteration of generation can only be explained by the Theory of Descent.
-
-The same remark applies to a kindred form of propagation, which is still
-more remarkable, and which I discovered in 1864, near Nice, in the
-Elephant-jellies (Geryonida), and called _alloeogony_, or
-_alloeogenesis_. In this case two completely distinct forms of medusa
-are descended from one another; the larger and more highly developed
-generation (11), Geryonia, or Carmarina, is six-rayed, with six foliated
-sexual organs, and six very movable marginal filaments. From the centre
-of its bell-shaped cup, like the tongue of a bell, hangs a long
-proboscis, at the end of which is the opening of the mouth and stomach.
-In the cavity of the stomach is a long, tongue-shaped bunch of buds
-(which on Plate VII. (_n_) is extended from the mouth on the left like a
-tongue). On this tongue, when the Geryonia is sexually ripe, there bud a
-number of small medusæ. They are, however, not Geryoniæ, but belong to
-an entirely distinct but very different form of medusa, namely, to the
-genus Cunina, of the family of the _Æginida_. This Cunina (12) is very
-differently constructed; it has a flat, semi-globular cup without
-proboscis, consists in early life of six divisions, later of sixteen,
-and has sixteen bag-shaped sexual organs, and sixteen short, stiff, and
-strongly curved tentacles. A further explanation of this wonderful
-alloeogenesis may be found in my "Contributions to the Natural History
-of the Hydromedusæ." (_Leipzig_, Englemann, 1865), the first part of
-which contains a monograph of the Elephant-jellies, or Geryonida,
-illustrated by six copper-plates.
-
-Even more interesting and instructive than these remarkable relations
-are the vital phenomena of the _Siphonophora_, whose wonderful
-polymorphism I have frequently spoken of, and described in a popular
-manner in my lecture on "Differentiation in Nature and Human Life."(37)
-(Compare vol. i. p. 270, and vol. ii. p. 140.) An example of this is
-given in Plate VII. in the drawing of the beautiful Physophora (13).
-This swimming stock or colony of hydromedusæ is kept floating on the
-surface of the sea by a small swimming bladder filled with air, which in
-the drawing is seen rising above the surface of the water. Below it is a
-column of four pairs of swimming bells, which eject water, and thereby
-set the whole colony in motion. At the lower end of the column of
-swimming bells is a crown-shaped wreath of curved spindle-shaped
-_sensitive polyps_, which also serve as a covering, under the protection
-of which the other individuals of the stock (the eating, catching, and
-reproductive persons) are hidden. The _ontogenesis_ of the Siphonophora
-(and especially of this Physophora), I first observed in Lanzerote, one
-of the Canary Islands, in 1866, and described in my "History of the
-Development of the Siphonophora," and added fourteen plates for its
-explanation. (Utrecht, 1869). It is rich in interesting facts, which can
-only be explained by the Theory of Descent.
-
-Another circumstance, which is also only explicable by the Theory of
-Descent, is the remarkable change of generation in the higher medusæ,
-the disc-jellies (Discomedusæ, vol. ii. p. 136), a representative of
-which is given at the top of Plate VII., in the centre (rather in the
-background), namely, a Pelagia (14). From the bottom of the bell-shaped
-cup, which is strongly arched and the rim of which is neatly indented,
-there hang four very long and strong arms. The non-sexual polyps, from
-which these disc-jellies are derived, are exceedingly simple primæval
-polyps, differing very little from the common fresh-water polyp (Hydra).
-The alternation of generation in these Discomedusæ has also been
-described in my lecture on Differentiation,(37) and there illustrated by
-the Aurelia by way of example.
-
-Finally, the last class of Zoophytes, the group of comb-jellies
-(Ctenophora, vol. ii. p. 142), has two representatives on Plate VII. To
-the left, in the centre, between the Æquorea (9), the Physophora (13),
-and the Cunina (12), is a long and thin band like a belt (15), winding
-like a snake; this is the large and splendid _Venus' girdle_ of the
-Mediterranean (Cestum), the colours of which are as varied as those of
-the rainbow. The actual body of the animal, which lies in the centre of
-the long belt, is very small, and constructed exactly like that of the
-_melon-jelly_ (Cydippe), which floats above to the left (16). On the
-latter are visible the eight characteristic fringed bands, or ciliated
-combs, of the ctenophora, and also two long tentacles which extend right
-across the page, and are fringed with still finer threads.
-
-
-  PLATES VIII. AND IX. (_Between pages 170 and 171, Vol. II._)
-
-_History of the Development of Star-fishes_ (_Echinoderma_, or
-_Estrella_). The two plates exhibit their alternation of generation
-(vol. ii. p. 168), with an example from each of the four classes of
-Star-fishes. The sea-stars (Asterida) are represented by Uraster (_A_),
-the sea-lilies (Crinoida) by Comatula (_B_), the sea-urchins (Echinida)
-by Echinus (_C_), and finally, the sea-cucumbers (Holothuriæ) by Synapta
-(_D_). (Compare vol. ii. pp. 166 and 176.) The successive stages of
-development are marked by the numbers 1-6.
-
-Plate VIII. represents the individual development of the first and
-non-sexual generation of Star-fishes, that is, of the _nurses_ (usually,
-but erroneously, called larvæ). These nurses possess the form-value of a
-simple, unsegmented worm-individual. Fig. 1 represents the egg of the
-four Star-fishes; and it, in all essential points, agrees with that of
-man and of other animals. (Compare vol. i. p. 297, Fig. 5.) As in man,
-the protoplasm of the egg-cell (the yolk) is surrounded by a thick,
-structureless membrane (zona pellucida), and contains a globular,
-cell-kernel (nucleus), as clear as glass, which again encloses a
-nucleolus. Out of the fertilised egg of the Star-fish (Fig. _A_ 1) there
-develops in the first place, by the repeated sub-division of cells, a
-globular mass of homogeneous cells (Fig. 6, vol. i. p. 299), and this
-changes into a very simple nurse, which has almost the same shape as a
-wooden shoe (Fig. _A_ 2-_D_ 2). The edge of the opening of the shoe is
-bordered by a fringe of cilia, the ciliary movements of which keep the
-microscopically small and transparent nurse swimming about freely in the
-sea. This fringe of cilia is marked in Fig. _A_ 2-_A_ 4, on Plate VII.,
-by the narrow alternately light and dark seam. The nurse then, in the
-first place, forms a perfectly simple intestinal canal for nutrition,
-mouth (_o_), stomach (_m_) and anus (_a_). Later, the windings of the
-fringe of cilia become more complicated, and there arise arm-like
-processes (Fig. _A_ 3-_D_ 3). In sea-stars (_A_ 4) and sea-urchins (_C_
-4) these arm-like processes, which are fringed with cilia, afterwards
-become very long. But in the case of sea-lilies (_B_ 3) and
-sea-cucumbers (_D_ 4), instead of this, the fringe of cilia, which at
-first, through winding in and out, forms one closed ring, changes
-subsequently into a succession of separate ciliated girdles, one lying
-behind the other.
-
-In the interior of this curious nurse there then develops, by a
-non-sexual process of generation, namely, by the formation of internal
-buds or germ-buds (round about the stomach), the second generation of
-Star-fishes, which later on become sexually ripe. This second
-generation, which is represented on Plate IX. in a fully developed
-condition, exists originally as a stock or cormus of five worms,
-connected at one end in the form of a star, as is most clearly seen in
-the sea-stars, the most ancient and original form of the star-fishes.
-The second generation, which grows at the expense of the first,
-appropriates only the stomach and a small portion of the other organs of
-the latter, but forms for itself a new mouth and anus. The fringe of
-cilia, and the other parts of the body of the nurse, afterwards
-disappear. The second generation (_A_ 5-_D_ 5), is at first smaller or
-not much larger than the nurse, whereas, by growth, it afterwards
-becomes more than a hundred times, or even a thousand times, as large.
-If the ontogeny of the typical representatives of the four classes of
-Star-fishes be compared, it is easily seen that the original kind of
-development has been best preserved in sea-stars (_A_) and sea-urchins
-(_C_) by inheritance, whereas in sea-lilies (_B_) and sea-cucumbers it
-has been suppressed according to the laws of abbreviated inheritance
-(vol. i. p. 212).
-
-Plate IX. shows the fully developed and sexually mature animals of the
-second generation from the mouth side, which, in the natural position of
-Star-fishes (when creeping at the bottom of the sea), in sea-stars (_A_
-6) and sea-urchins (_C_ 6), is below, in sea-lilies (_B_ 6) above, and
-in sea-cucumbers (_D_ 6) in front. In the centre we perceive, in all the
-four Star-fishes, the star-shaped, five-pointed opening of the mouth. In
-sea-stars, from each arm there extend several rows of little sucking
-feet, from the centre of the under-side of each arm to the end. In
-sea-lilies (_B_ 6), each arm is split and feather-like from its base
-upwards. In sea-urchins (_C_ 6) the five rows of sucking feet are
-divided by broader fields of spines. In sea-cucumbers, lastly (_D_ 6),
-on the worm-like body it is sometimes only the five rows of little feet,
-sometimes only the feathery tentacles surrounding the mouth, from five
-to fifteen (in this case ten), that are externally visible.
-
-
-  PLATES X. AND XI. (_Between pages 174 and 175, Vol. II._)
-
-_Historical Development of the Crab-fish_ (Crustacea).--The two plates
-illustrate the development of the different Crustacea from the nauplius,
-their common primæval form. On Plate XI. six Crustacea, from six
-different orders, are represented in a fully developed state, whereas on
-Plate X. the early nauplius stages are given. From the essential
-agreement between the latter we may, on the ground of the fundamental
-law of biogeny, with full assurance maintain the derivation of the
-different Crustacea from a single, common primary form, a long since
-extinct Nauplius, as was first shown by Fritz Müller in his excellent
-work "Für Darwin."(16)
-
-Plate X. represents the _early nauplius stages_ from the ventral side,
-so that the three pairs of legs, on the short, three-jointed trunk are
-distinctly visible. The first of these pairs of legs is simple and
-unsegmented, whereas the second and third pairs are forked. All three
-pairs are furnished with stiff bristles, which, through the paddling
-motion of the legs, serve as an apparatus for swimming. In the centre of
-the body, the perfectly simple, straight intestinal canal is visible,
-possessing a mouth in front, and an anal orifice behind. In front, above
-the mouth, lies a simple, single eye. All the six forms of nauplius
-entirely agree in all these essential characteristics of organization,
-whereas the six fully developed forms of Crustacea belonging to them,
-Plate XI., are extremely different in organisation. The differences of
-the six nauplius forms are confined to quite subordinate and unessential
-relations in regard to size of body, and the formation of the covering
-of the skin. If they could be met with in this form in a sexually mature
-condition, no zoologist would hesitate to regard them as six different
-species of one genus. (Compare vol. ii. p. 175.)
-
-Plate XI. represents those fully developed and sexually mature forms of
-Crustacea, as seen from the right side, which have ontogenetically
-(hence also phylogenetically) developed out of the six kinds of
-nauplius. Fig. _A c_ shows a freely swimming fresh-water crab (Limnetis
-brachyurus) from the order of the Leaf-foot Crabs (Phyllopoda), slightly
-enlarged. Of all the still living Crustacea, this order, which belongs
-to the legion of Gill-foot Crabs (Branchiopoda), stands nearest to the
-original, common primary form of nauplius. The Limnetis is enclosed in a
-bivalved shell, like a mussel. Our drawing (which is copied from Grube)
-represents the body of a female animal lying in the left shell; the
-right half of the shell has been removed. In front, behind the eye, we
-see the two feelers (antennæ), and behind them the twelve leaf-shaped
-feet of the right side of the body, behind on the back (under the
-shell), the eggs. Above, in front, the animal is fixed to the shell.
-
-Fig. _B c_ represents a common, freely swimming fresh-water crab
-(Cyclops quadricornis) from the order of Oar-legged crabs (Eucopepoda),
-highly magnified. In front, below the eye, we see the two feelers of the
-right side, the foremost of which is longer than the hinder one. Behind
-these are the gills, and then the four paddling legs of the right side.
-Behind these are the two large egg-sacks, which, in this case, are
-attached to the end of the hinder part of the body.
-
-Fig. _C c_ is a parasitic Oar-legged crab (Lernæocera esocina), from the
-order of fish lice (Siphonostoma). These peculiar crabs, which were
-formerly regarded as worms, have originated, by adaptation to a
-parasitical life, out of freely swimming, Oar-legged crabs (Eucopepoda),
-and belong to the same legion (Copepoda, vol. ii. p. 176). By adhering
-to the gills on the skin of fish or other crabs, and feeding on the
-juice of these creatures, they forfeited their eyes, legs, and other
-organs, and developed into formless, inarticulated sacks, which, on a
-mere external examination, we should never suppose to be animals. On the
-ventral side only there exist, in the shape of short, pointed bristles,
-the last remains of legs which have now almost entirely disappeared. Two
-of these rudimentary pairs of legs (the third and fourth) are seen in
-our drawing on the right. Above, on the head, we see thick, shapeless
-appendages, the lower ones of which are split. In the centre of the body
-is seen the intestinal canal, which is surrounded by a dark covering of
-fat. At its posterior end is the ovary, and the cement-glands of the
-female sexual apparatus. The two large egg-sacks hang externally (as in
-the Cyclops, Fig. _B_). Our Lernæocera is represented in half profile,
-and is copied from Claus. (Compare Claus, "Die Copepoden-Fauna von
-Nizza. Ein Beitrag zur Characteristik der Formen und deren Abänderungen
-im Sinne Darwins." Marburg, 1866).
-
-Fig. _D c_ represents a so-called "duck mussel" (Lepas anatifera), from
-the order of the Barnacle crabs (Cirripedia). These crabs, upon which
-Darwin has written a very careful monograph, are, like mussels, enclosed
-in a bivalved, calcareous case, and hence were formerly (even by Cuvier)
-universally regarded as a kind of mussel, or mollusc. It was only from a
-knowledge of their ontogeny, and their early nauplius form (_D n_, Plate
-VIII.), that their crustacean nature was proved. Our drawing shows a
-"duck mussel" of the natural size, from the right side. The right half
-of the bivalved shell has been removed, so that the body is seen lying
-in the left half of the shell. From the rudimentary head of the Lepas
-there issues a long, fleshy stalk (curving upwards in our drawing); by
-means of it the Barnacle crab grows on rocks, ships, etc. On the ventral
-side are six pairs of feet. Every foot is forked and divided into two
-long, curved, or curled "tendrils" furnished with bristles. Above and
-behind the last pair of feet projects the thin cylindrical tail.
-
-Fig. _E c_ represents a parasitic sack-crab (Sacculina purpurea) from
-the order of Root-crabs (Rhizocephala). These parasites, by adaptation
-to a parasitical life, have developed out of Barnacle crabs (Fig. _D
-c_), much in the same way as the fish-lice (_C c_), out of the freely
-swimming Oar-legged crabs (_B c_). However, the suppression, and the
-subsequent degeneration, of all of the organs, has gone much further in
-the present case than in most of the fish-lice. Out of the articulated
-crab, possessing legs, intestine, and eye, and which in an early stage
-as nauplius (_E n_, Plate VIII.), swam about freely, there has developed
-a formless, unsegmented sack, a red sausage, which now only contains
-sexual organs (eggs and sperm) and an intestinal rudiment. The legs and
-the eye have completely disappeared. At the posterior end is the opening
-of the genitals. From the mouth grows a thick bunch of numerous
-tree-shaped and branching root-like fibres. These spread themselves out
-(like the roots of a plant in the ground) in the soft hinder part of the
-body of the hermit-crab (Pagurus), upon which the root-crab lives as a
-parasite, and from which it draws its nourishment. Our drawing (_E c_),
-a copy of Fritz Müller's, is slightly enlarged, and shows the whole of
-the sausage-shaped sack-crab, with all its root-fibres, when drawn out
-of the body upon which it lives.
-
-Fig. _F c_ is a _shrimp_ (Peneus Mülleri), from the order of _ten-foot_
-crabs (Decapoda), to which our river cray-fish, and its nearest
-relative, the lobster, and the short-tailed shore-crabs also belong.
-This order contains the largest and, gastronomically, the most important
-crabs, and belongs, together with the mouth-legged and split-legged
-crabs, to the legion of the stalk-eyed mailed crabs (Podophthalma). The
-shrimp, as well as the river crab, has in front, on each side below the
-eye, two long feelers (the first much shorter than the second), then
-three jaws, and three jaw-feet, then five very long legs (the three
-fore ones of which, in the Peneus, are furnished with nippers, and the
-third of which is the longest). Finally, on the first five joints of the
-hinder part of the body there are other five pairs of feet. This shrimp,
-which is one of the most highly developed and perfect crabs, originates
-(according to Fritz Müller's important discovery) out of a nauplius (_F
-n_ Plate VIII.), and consequently proves that the higher Crustacea have
-developed out of the same form as the lower ones, namely, the nauplius.
-(Compare vol. ii. p. 175.)
-
-
-  PLATES XII. AND XIII. (_Between pages 200 and 201, Vol. II._)
-
-_Blood relationship between the Vertebrata and the Invertebrata._
-(Compare vol. ii. pp. 152 and 201.) It is definitely established by
-Kowalewski's important discovery, which was confirmed by Kupffer, that
-the ontogeny of the lowest vertebrate animal--the Lancelet, or
-Amphioxus--agrees in all essential outlines completely with that of the
-invertebrate Sea-squirts, or Ascidiæ, from the class of Sea-sacks, or
-Tunicata. On our two plates, the ascidia is marked by _A_, the amphioxus
-by _B_. Plate XIII. represents these two very different animal-forms in
-a _fully developed_ state, as seen from the _left side_, the end of the
-mouth above, the opposite end below. Hence, in both figures the dorsal
-side is to the right, the ventral to the left. Both figures are slightly
-magnified, and the internal organisation of the animals is distinctly
-visible through the transparent skin. The full-grown ascidia (Fig. _A_
-6) grows at the bottom of the ocean, from whence it cannot move, and
-clings to stones and other objects by means of peculiar roots (_w_) like
-a plant. The full-grown amphioxus, on the other hand (Fig. _B_ 6), swims
-about freely like a small fish. The letters on both figures indicate the
-same parts: (_a_) orifice of the mouth; (_b_) orifice of the body, or
-porus abdominalis; (_c_) dorsal rod, or chorda dorsalis; (_d_)
-intestine; (_e_) ovary; (_f_) oviduct (same as the sperm-duct); (_g_)
-spinal marrow; (_h_) heart; (_i_) blind-sac of the intestine; (_k_)
-gill basket (respiratory cavity); (_l_) cavity of the body; (_m_)
-muscles; (_n_) testicle (in the ascidia united with the ovary into a
-hermaphrodite gland); (_o_) anus; (_p_) genital orifice; (_q_)
-well-developed embryos in the body cavity of the ascidia; (_r_) rays of
-the dorsal fin of the amphioxus; (_s_) tail-fin of the amphioxus; (_w_)
-roots of the ascidia.
-
-Plate XII. shows the _Ontogenesis_, or the individual development of the
-_Ascidia_ (_A_) and the _Amphioxus_ (_B_) in five different stages
-(1-5). Fig. 1 is the egg, a simple cell like the egg of man and all
-other animals (Fig. _A_ 1 the egg of the ascidia, Fig. _B_ 1 the egg of
-the amphioxus). The actual cell-substance, or the protoplasm of the
-egg-cell (_z_), the so-called yolk, is surrounded by a covering
-(cell-membrane, or yolk-membrane), and encloses a globular cell-kernel,
-or nucleus (_y_), the latter, again, contains a kernel-body, or
-nucleolus (_x_); when the egg begins to develop, the egg-cell first
-subdivides into two cells. By another sub-division there arise four
-cells (Fig. _A_ 2, _B_ 2), and out of these, by repeated sub-division,
-eight cells (vol. i. p. 190, Fig. 4 _C_, _D_). By fluid gathering in the
-interior these form a globular bladder bounded by a layer of cells. On
-one spot of its surface the bladder is turned inwards in the form of a
-pocket (Fig. _A_ 4, _B_ 4). This depression is the beginning of the
-intestine, the cavity (_d_ 1) of which opens externally by the
-provisional larval-mouth (_d_ 4). The body-wall, which is at the same
-time the stomach-wall, now consists of two layers of cells--the
-germ-layers. The globular larva (Gastrula), now grows in length. Fig.
-_A_ 5 represents the larva of the ascidia, Fig. _B_ 5 that of the
-amphioxus, as seen from the left side in a somewhat more advanced state
-of development. The orifice of the intestine (_d_ 1) has closed. The
-dorsal side of the intestine (_d_ 2) is concave, the ventral side (_d_
-3) convex. Above the intestinal tube, on its dorsal side, the neural
-tube, the beginning of the spinal marrow, is being formed, its cavity
-still opens externally in front (_g_ 2). Between the spinal marrow and
-the intestine has arisen the spinal rod, or chorda dorsalis (Notochord)
-(_c_), the axis of the inner skeleton. In the larva of the ascidia this
-rod (_c_) proceeds along the long rudder-tail, a larval organ, which is
-cast off in later transformation. Yet there still exist some very small
-ascidiæ (Appendicularia) which do not become transformed and attached,
-but which through life swim about freely in the sea by means of their
-rudder-tail.
-
-The ontogenetic facts which are systematically represented on Plate XII.
-and which were first discovered in 1867, deserve the greatest attention,
-and, indeed, cannot be too highly estimated. They fill up the gap which,
-according to the opinion of older zoologists existed between the
-vertebrate and the so-called "invertebrate" animals. This gap was
-universally regarded as so important and so undeniable, that even
-eminent zoologists, who were not disinclined to adopt the theory of
-descent, saw in this gap one of the chief obstacles against it. Now that
-the ontogeny of the amphioxus and the ascidia has set this obstacle
-completely aside, we are for the first time enabled to trace the
-pedigree of man beyond the amphioxus into the many-branching tribe of
-"invertebrate" worms, from which all the other higher animal tribes have
-originated.
-
-If our speculative philosophers, instead of occupying themselves with
-castles in the air, were to give their thoughts for some years to the
-facts represented on Plates XII. and XIII., as well as to those on
-Plates II. and III., they would gain a foundation for true
-philosophy--for the knowledge of the universe firmly based on
-experience--which would be sure to influence all regions of thought.
-These facts of ontogenesis are the indestructible foundations upon which
-the monistic philosophy of future times will erect its imperishable
-system.
-
-
-  PLATE XIV. (_Between pages 206 and 207, Vol. II._)
-
-_Monophyletic, or One-rooted Pedigree of the Vertebrate Animal tribe_,
-representing the hypothesis of the common derivation of all vertebrate
-animals, and the historical development of their different classes
-during the palæontological periods of the earth's history. (Compare
-Chapter XX. vol. ii. p. 192.) The horizontal lines indicate the periods
-(mentioned in vol. ii. p. 14) of the organic history of the earth during
-which the deposition of the strata containing fossils took place. The
-vertical lines separate the classes and sub-classes of vertebrata from
-one another. The tree-shaped and branching lines, by their greater or
-lesser number and thickness, indicate the approximate degree of
-development, variety, and perfection, which each class probably attained
-in each geological period. In those classes which, on account of the
-soft nature of their bodies, could not leave any fossil remains (which
-is especially the case with Prochordata, Acrania, Monorrhina, and
-Dipneusta) the course of development is hypothetically suggested on the
-ground of arguments derived from the three records of
-creation--comparative anatomy, ontogeny, and palæontology. The most
-important starting-points for the hypothetical completion of the
-palæontological gaps are here, as in all cases, furnished by the
-_fundamental law of biogeny_, which asserts the inner _causal-nexus
-existing between ontogeny and phylogeny_. (Compare vol. i. p. 310, and
-vol. ii. p. 200; also Plates VIII.-XIII.) In all cases we have to regard
-the individual development (determined by the laws of Inheritance but
-modified by the laws of Adaptation) as short and quick repetitions of
-the palæontological development of the tribe. This proposition is the
-"ceterum censeo" of our theory of development.
-
-The statements of the first appearance, or the period of the origin of
-the individual classes and sub-classes of vertebrate animals (apart from
-the hypothetical filling in mentioned just now), are taken as strictly
-as possible from palæontological facts. It must, however, be observed,
-that in reality the origin of most of the groups probably took place one
-or two periods earlier than fossils now indicate. In this I agree with
-Huxley's views; but on Plates V. and XIV. I have disregarded this
-consideration in order not to go too far from palæontological facts.
-
-The numbers signify as follows (compare also Chapter XX. and vol. ii.
-pp. 204, 206):--1. Animal Monera; 2. Animal Amoebæ; 3. Community of
-Amoebæ (Synamoebæ); 4. Ciliated Infusoria without mouths; 5. Ciliated
-Infusoria with mouths; 6. Gliding worms (Turbellaria); 7. Sea-sacks
-(Tunicata); 8. Lancelet (Amphioxus); 9. Hag (Myxinoida); 10. Lamprey
-(Petromyzontia); 11. Unknown forms of transition from single-nostriled
-animals to primæval fishes; 12. Silurian primæval fish (Onchus, etc.);
-13. Living primæval fishes (sharks, rays, Chimæræ); 14. Most ancient
-(Silurian) enamelled fishes (Pteraspis); 15. Turtle fishes (Pamphracti);
-16. Sturgeons (Sturiones); 17. Angular-scaled enamelled fishes
-(Rhombiferi); 18. Bony pike (Lepidosteus); 19. Finny pike (Polypterus);
-20. Hollow-boned fishes (Coeloscolopes); 21. Solid boned fishes
-(Pycnoscolopes); 22. Bald pike (Amia); 23. Primæval boned fishes
-(Thrissopida); 24. Bony fishes with air passage to the swimming bladder
-(Physostomi); 25. Bony fishes without air passage to the swimming
-bladder (Physoclisti); 26. Unknown forms of transition between primæval
-fishes and amphibious fishes; 27. Ceratodus; 27_a_. Extinct Ceratodus
-from the Trias; 27_b_. Living Australian Ceratodus; 28. African
-amphibious fishes (Protopterus) and American amphibious fishes
-(Lepidosiren); 29. Unknown forms of transition between primæval fishes
-and amphibia; 30. Enamelled heads (Ganocephala); 31. Labyrinth toothed
-(Labyrinthodonta); 32. Blind burrowers (Cæciliæ); 33. Gilled amphibia
-(Sozobranchia); 34. Tailed amphibia (Sozura); 35. Frog amphibia (Anura);
-36. Dichthacantha (Proterosaurus); 37. Unknown forms of transition
-between Amphibia and Protamnia; 38. Protamnia (common primary form of
-all Amnion animals); 39. Primary mammals (Promammalia); 40. Primæval
-reptiles (Proreptilia); 41. (Thecodontia); 42. Primæval dragons
-(Simosauria); 43. Serpent dragons (Plesiosauria); 44. Fish dragons
-(Ichthyosauria); 45. Teleosauria (Amphicoela); 46. Steneosauria
-(Opisthocoela); 47. Alligators and Crocodiles (Prosthocoela); 48.
-Carnivorous Dinosauria (Harpagosauria); 49. Herbivorous Dinosauria
-(Therosauria); 50. Mæstricht lizards (Mosasauria); 51. Common primary
-form of Serpents (Ophidia); 52. Dog-toothed beaked lizards (Cynodontia);
-53. Toothless beaked lizards (Cryptodontia); 54. Long-tailed flying
-lizards (Rhamphorhynchi); 55. Short-tailed flying lizards
-(Pterodactyli); 56. Land tortoises (Chersita); 57. Birds--reptiles
-(Tocornithes), transition form between reptiles and birds; 58. Primæval
-griffin (Archæopteryx); 59. Water beaked-animal (Ornithorhynchus); 60.
-Land beaked-animal (Echidna); 61. Unknown forms of transition between
-Cloacals and Marsupials; 62. Unknown forms of transition between
-Marsupials and Placentals; 63. Tuft Placentals (Villiplacentalia); 64.
-Girdle Placentals (Zonoplacentalia); 65. Disc Placentals
-(Discoplacentalia); 66. Man (Homo pithecogenes, by Linnæus erroneously
-called, Homo sapiens.)
-
-
-  PLATE XV. (_After page 369, Vol. II._)
-
-_Hypothetical Sketch of the Monophyletic Origin and the Diffusion of the
-Twelve Species of Men from Lemuria over the earth._ The _hypothesis_
-here geographically sketched of course only claims an entirely
-_provisional value_, as in the present imperfect state of our
-anthropological knowledge it is simply intended to show how the
-distribution of the human species, from a single primæval home, may be
-_approximately_ indicated. The probable primæval home, or "Paradise," is
-here assumed to be _Lemuria_, a tropical continent at present lying
-below the level of the Indian Ocean, the former existence of which in
-the tertiary period seems very probable from numerous facts in animal
-and vegetable geography. (Compare vol. i. p. 361, and vol. ii. p. 315.)
-But it is also very possible that the hypothetical "cradle of the human
-race" lay further to the east (in Hindostan or Further India), or
-further to the west (in eastern Africa). Future investigations,
-especially in comparative anthropology and palæontology, will, it is to
-be hoped, enable us to determine the probable position of the primæval
-home of man more definitely than it is possible to do at present.
-
-If in opposition to our monophyletic hypothesis, the polyphyletic
-hypothesis--which maintains the origin of the different human species
-from several different species of anthropoid ape--be preferred and
-adopted, then, from among the many possible hypotheses which arise, the
-one deserving most confidence seems to be that which assumes a double
-pithecoid root for the human race namely, an Asiatic and an African
-root. For it is a very remarkable fact, that the African man-like apes
-(gorilla and chimpanzee) are characterized by a distinctly long-headed,
-or dolichocephalous, form of skull, like the human species peculiar to
-Africa (Hottentots, Caffres, Negroes, Nubians). On the other hand, the
-Asiatic man-like apes (especially the small and large orang), by their
-distinct, short-headed, or brachycephalous, form of skull agree with
-human species especially characteristic of Asia (Mongols and Malays).
-Hence, one might be tempted to derive the latter (the Asiatic man-like
-apes and primæval men) from a common form of brachycephalous ape, and
-the former (the African man-like apes and primæval men) from a common
-dolichocephalous form of ape.
-
-In any case, tropical Africa and southern Asia (and between them
-Lemuria, which formerly connected them) are those portions of the earth
-which deserve the first consideration in the discussion as to the
-primæval home of the human race; America and Australia are, on the other
-hand, entirely excluded from it. Even Europe (which is in fact but a
-western peninsula of Asia) is scarcely of any importance in regard to
-the "Paradise question."
-
-It is self-evident that the migrations of the different human species
-from their primæval home, and their geographical distribution, could on
-our Plate XV. be indicated only in a very general way, and in the
-roughest lines. The numerous migrations of the many branches and tribes
-in all directions, as well as the very important re-migrations, had to
-be entirely disregarded. In order to make these latter in some degree
-clear, our knowledge would, in the first place, need to be much more
-complete, and secondly, we should have to make use of an atlas with a
-number of plates showing the various migrations. Our Plate XV. claims no
-more than to indicate, in a very general way, the approximate
-geographical dispersion of the twelve human species as it existed in the
-fifteenth century (before the general diffusion of the Indo-Germanic
-race), and as it can be sketched out approximately, so as to harmonize
-with our hypothesis of descent. The geographical barriers to diffusion
-(mountains, deserts, rivers, straits, etc.), have not been taken into
-consideration in this general sketch of migration, because, in earlier
-periods of the earth's history, they were quite different in size and
-form from what they are to-day. The gradual transmutation of catarrhine
-apes into pithecoid men probably took place in the tertiary period in
-the hypothetical Lemuria, and the boundaries and forms of the present
-continents and oceans must then have been completely different from what
-they are now. Moreover, the mighty influence of the ice period is of
-great importance in the question of the migration and diffusion of the
-human species, although it as yet cannot be more accurately defined in
-detail. I here, therefore, as in my other hypotheses of development,
-expressly guard myself against any dogmatic interpretation; they are
-nothing but _first attempts_.
-
-
-
-
-INDEX.
-
-  A
-
-  ABYSSINIANS, ii. 323, 330
-
-  Acalephæ, ii. 141
-
-  Acoelomi, ii. 148, 151
-
-  Acrania, ii. 196, 198, 200, 204
-
-  Acyttaria, ii. 51, 62
-
-  Adaptation, i. 90, 156, 219
-
-  ---- actual, i. 225, 231
-
-  ---- correlative, i. 241
-
-  ---- cumulative, i. 233
-
-  ---- direct, i. 225, 231
-
-  ---- divergent, i. 247
-
-  ---- indirect, i. 224, 227
-
-  ---- individual, i. 228
-
-  ---- irregular, i. 229
-
-  ---- monstrous, i. 229
-
-  ---- potential, i. 224, 227
-
-  ---- sexual, i. 230
-
-  ---- universal, i. 231
-
-  ---- unlimited, i. 249
-
-  Agassiz, Louis, i. 61
-
-  Agassiz's conception of the universe, i. 65
-
-  ---- essay on classification, i. 61
-
-  ---- history of creation, i. 63
-
-  ---- history of development, i. 64
-
-  ---- idea of species, i. 65
-
-  Albuminous bodies, i. 331
-
-  Algæ, ii. 81, 82, 83
-
-  Alluvial system, ii. 15
-
-  Altaians, ii. 309, 317
-
-  Alternation of generations, i. 206
-
-  Americans, ii. 309, 318
-
-  Amnion animals, ii. 204, 219
-
-  Amniota, ii. 204, 219
-
-  Amoebæ, ii. 53, 279
-
-  Amoeboidea, ii. 53
-
-  Amphibia, ii. 209, 216
-
-  Amphioxus, ii. 198, 285
-
-  Amphirrhina, ii. 203, 205
-
-  Anamnionata, ii. 204
-
-  Animal Plants, ii. 144
-
-  Angiospermæ, ii. 83, 111
-
-  Annelida, ii. 133, 149, 151
-
-  Anorgana, i. 5, 328
-
-  Anorganology, i. 6
-
-  Anthozoa, ii. 143
-
-  Anthropocentric conception of the universe, i. 38
-
-  Anthropoides, ii. 270, 275, 292
-
-  Anthropolithic period, ii. 15, 17
-
-  Anthropology, i. 7
-
-  Anthropomorphism, i. 18, 66
-
-  Ape-like men, ii. 293, 300
-
-  Apes, ii. 241, 268, 270
-
-  Arabians, ii. 323, 330
-
-  Arachnida, ii. 180, 182
-
-  Archelminthes, ii. 148
-
-  Archezoa, ii. 132, 134
-
-  Archigony, i. 183, 338
-
-  Archilithic period, ii. 8, 14
-
-  Arians, ii. 323, 331
-
-  Aristotle, i. 55, 76
-
-  Arthropoda, ii. 132
-
-  Articulata, ii. 119
-
-  Ascidia, ii. 152, 200
-
-  Ascones, ii. 141
-
-  Asterida, ii. 164, 166
-
-  Atavism, i. 207
-
-  Australians, ii. 308, 314
-
-  Autogeny, i. 339
-
-
-  B
-
-  BÄR, CARL ERNST, i. 109
-
-  ---- doctrine of filiation, i. 109
-
-  ---- theory of development, i. 294
-
-  ---- types of animals, i. 53; ii. 119
-
-  Basques, ii. 322
-
-  Bathybius, i. 184, 344; ii. 53
-
-  Batrachians, ii. 204
-
-  Bats, ii. 240, 261
-
-  Beaked mammals, ii. 233, 239
-
-  ---- reptiles, ii. 224, 226
-
-  Belief, i. 9; ii. 335
-
-  Berbers, ii. 323, 330
-
-  Biogenesis, fundamental law of, i. 309; ii. 33
-
-  Biology, i. 6
-
-  Birds, ii. 204, 226
-
-  Brachiopoda, ii. 157
-
-  Brain, bladder of, in man, i. 304
-
-  ---- development of, i. 303
-
-  Bruno Giordano, i. 22, 70
-
-  Bryozoa, ii. 150, 152
-
-  Buch, Leopold, i. 107
-
-  Büchner, Louis, i. 110
-
-  Buds, formation of, i. 192
-
-
-  C
-
-  CAFFRES, ii. 312, 333
-
-  Calcispongiæ, ii. 140, 144
-
-  Cambrian system, ii. 9, 15
-
-  Carbon, i. 330, 335
-
-  ---- theory of, i. 335
-
-  Carboniferous system, ii. 11, 15
-
-  Carus Victor, i. 110
-
-  Catallacta, i. 51, 59
-
-  Catarrhini, ii. 270, 272
-
-  Caucasians, ii. 309, 321
-
-  Causa finalis, i. 34, 75
-
-  Causal conception of the universe, i. 18, 74
-
-  Cells, i. 187, 346
-
-  ---- formation of, i. 347
-
-  ---- theory of, i. 346
-
-  Cell-kernel, i. 188
-
-  ---- membrane, i. 188
-
-  ---- substance, i. 186
-
-  Cænolithic period, ii. 14, 16
-
-  Cephalopoda, ii. 160, 162
-
-  Chamisso, Adalbert, i. 206
-
-  Change of climate, i. 363
-
-  Chelophora, ii. 240, 257
-
-  Chinese, ii. 309, 317
-
-  Chorology, i. 351
-
-  Cloacal animals, ii. 234, 239
-
-  Cochlides, ii. 159, 160
-
-  Coelenterata, ii. 136, 144
-
-  Coelomati, ii. 148, 151
-
-  Coniferæ, ii. 82, 110
-
-  Constructive forces, i. 90, 253, 337
-
-  Copernicus, i. 39
-
-  Corals, ii. 142, 144
-
-  Coreo-Japanese, ii. 309, 317
-
-  Cormophytes, ii. 80
-
-  Correlation of parts, i. 218
-
-  Cosmogeny, i. 321
-
-  Cosmological gas theory, i. 323
-
-  Crabs, ii. 174, 176
-
-  Craniota, ii. 198, 204
-
-  Creation, centres of, i. 352
-
-  ---- the, i. 8
-
-  Creator, the, i. 64, 70
-
-  Cretaceous system, ii. 12, 15
-
-  Crinoides, ii. 166, 171
-
-  Crocodiles, ii. 223, 224
-
-  Crustacea, ii. 173, 176
-
-  Cryptogamia, ii. 80, 82
-
-  Ctenophera, ii. 142, 144
-
-  Cultivated plants, i. 137
-
-  Curly-haired men, ii. 310, 333
-
-  Cuttles, ii. 160, 162
-
-  Cuvier, George, i. 50
-
-  Cuvier's dispute with Geoffroy, i. 88
-
-  ---- history of creation, i. 59
-
-  ---- palæontology, i. 54
-
-  ---- idea of species, i. 50
-
-  ---- theory of cataclysms, i. 58
-
-  ---- theory of revolutions, i. 58
-
-  ---- types of animals, i. 53; ii. 118
-
-  Cycadeæ, ii. 82, 110
-
-  Cyclostoma, ii. 202, 204
-
-  Cytod, i. 346
-
-
-  D
-
-  DARWIN, CHARLES, i. 131
-
-  Darwinism, i. 149
-
-  Darwin's life, i. 132
-
-  ---- travels, i. 132
-
-  ---- theory of corals, i. 133
-
-  ---- theory of selection, i. 150
-
-  ---- study of pigeons, i. 141
-
-  Darwin, Erasmus, i. 118
-
-  Deciduata, ii. 240, 255
-
-  Deduction, i. 85; ii. 357
-
-  Democritus, i. 22
-
-  Devonian system, ii. 11, 14
-
-  Diatomeæ, ii. 51, 60
-
-  Dicotylæ, ii. 82, 112
-
-  Didelphia, ii. 239
-
-  Differentiation, i. 270, 283
-
-  Diluvial system, ii. 15
-
-  Dipneusta, ii. 204, 212
-
-  Divergence, i. 270
-
-  Division of labour, i. 247
-
-  Domestic animals, i. 137
-
-  Dragons, ii. 225
-
-  Dravidas, ii. 308, 319
-
-  Dualistic conception of the universe, i. 20, 75
-
-  Dysteleology, i. 15; ii. 353
-
-
-  E
-
-  ECHINIDA, ii. 166, 171
-
-  Echinoderma, ii. 163, 166
-
-  Edentata, ii. 240, 254
-
-  Egg Animals, ii. 132, 134
-
-  Eggs, i. 190, 198
-
-  Egg of man, i. 190, 297; ii. 279
-
-  Egg, cleavage of the, i. 190, 299; ii. 280
-
-  Egyptians, ii. 323, 330
-
-  Elephants, ii. 257
-
-  Empiricism, i. 79; ii. 349
-
-  Eocene system, ii. 15, 16
-
-  Ethiopians, ii. 323, 330
-
-  Explanation of phenomena, i. 29
-
-
-  F
-
-  FERNS, ii. 82, 101
-
-  Fibrous plants, ii. 82
-
-  Final cause, i. 22
-
-  Fins, ii. 309, 317
-
-  Fishes, ii. 206, 208
-
-  Flagellata, ii. 51, 57
-
-  Flat-nosed apes, ii. 270, 272
-
-  Flat worms, ii. 148, 150
-
-  Flint cells, ii. 51, 60
-
-  Flowering plants, ii. 82, 108
-
-  Flower animals, ii. 143
-
-  Flowerless plants, ii. 80, 82
-
-  Flying animals, ii. 240, 261
-
-  Freke, i. 119
-
-  Fulatians, ii. 308, 320
-
-  Fungi, ii. 82
-
-
-  G
-
-  GANOID FISH, ii. 208, 210
-
-  Gastræa, ii. 127, 128, 281
-
-  Gastrula, ii. 126, 127
-
-  Gegenbaur, i. 312; ii. 179, 193
-
-  Gemmation, i. 192
-
-  Generation, i. 209
-
-  Genus, i. 41
-
-  Geocentric conception of the universe, i. 38
-
-  Geoffroy S. Hilaire, i. 86, 116
-
-  Germans, ii. 323, 331
-
-  Germ buds, formation of, i. 193
-
-  ---- cells, formation of, i. 194
-
-  Gibbon, ii. 270, 275
-
-  Gilled insects, ii. 174, 176
-
-  Gill-arches in man, i. 307
-
-  God, conception of, i. 70
-
-  Goethe, Wolfgang, i. 80
-
-  Goethe's conception of nature, i. 22
-
-  ---- discovery of mid-jaw bone, i. 84
-
-  ---- formative tendency i. 91, 253
-
-  ---- idea of God, i. 71
-
-  ---- investigations in nature, i. 81
-
-  ---- materialism, i. 23
-
-  ---- metamorphosis, i. 90
-
-  ---- metamorphosis of plants, i. 82
-
-  ---- philosophy of nature, i. 81
-
-  ---- theory of development, i. 92
-
-  ---- vertebræ of skull, i. 83
-
-  Genochoristus, i. 196
-
-  Gonochorism, i. 196
-
-  Gorilla, ii. 270
-
-  Grant, i. 119
-
-  Greeks, ii. 323, 331
-
-  Gregarinæ, ii. 133, 134
-
-  Gynmosperms, ii. 82, 109
-
-
-  H
-
-  HALISAURIA, ii. 204, 214
-
-  Hare-rabbit, i. 148, 275
-
-  Heliozoa, ii. 64
-
-  Herbert, i. 119
-
-  Heredity, i. 176
-
-  Hermaphrodites, i. 196
-
-  Herschel's cosmogeny, i. 321
-
-  Holothuriæ, ii. 166, 172
-
-  Hoofed animals, ii. 249, 252
-
-  Hooker, i. 119
-
-  Hottentots, ii. 311, 333
-
-  Human races, ii. 296, 305, 308
-
-  ---- soul, ii. 361
-
-  Huxley, i. 119, 145; ii. 268
-
-  Hybridism, i. 145, 210, 275
-
-  Hydromedusæ, ii. 143, 145
-
-
-  I
-
-  ICE PERIOD, i. 367; ii. 17
-
-  Indecidua, ii. 241, 249
-
-  Individual development, ii. 293
-
-  Indo-Chinese, ii. 309, 317
-
-  Indo-Germanic, ii. 323, 331
-
-  Induction, i. 85; ii. 357
-
-  Infusoria, ii. 132, 135
-
-  Inheritance, abridged, i. 212
-
-  Inheritance, acquired, i. 213
-
-  ---- adapted, i. 213
-
-  ---- amphigonous, i. 210
-
-  ---- conservative, i. 204
-
-  ---- constituted, i. 216
-
-  ---- contemporaneous, i. 217
-
-  ---- continuous, i. 205
-
-  ---- established, i. 216
-
-  ---- homochronous, i. 217
-
-  ---- interrupted, i. 205
-
-  ---- latent, i. 205
-
-  ---- mixed, i. 210
-
-  ---- progressive, i. 213
-
-  ---- sexual, i. 209
-
-  ---- simplified, i. 212
-
-  ---- uninterrupted, i. 205
-
-  ---- laws of, i. 204
-
-  Inophyta, ii. 82, 93
-
-  Insects, ii. 184
-
-  Insectivora, ii. 241, 259
-
-  Instinct, ii. 343
-
-  Invertebrata, ii. 118, 195
-
-  Iranians, ii. 323, 331
-
-
-  J
-
-  JAPANESE, ii. 309, 317
-
-  Jews, ii. 323, 330
-
-  Jura system, ii. 12, 14
-
-
-  K
-
-  KANT, IMMANUEL, i. 101, 321
-
-  Kant's Criticism of the faculty of judgment, i. 105
-
-  ---- mechanisms, i. 37, 102
-
-  ---- philosophy of nature, i. 101
-
-  ---- theory of descent, i. 103
-
-  ---- theory of development, i. 321
-
-  ---- theory of the formation of the universe, i. 101
-
-  Knowledge, à posteriori, i. 31; ii. 345
-
-  ---- à priori, i. 31; ii. 344
-
-
-  L
-
-  LABYRINTHULEÆ, ii. 51
-
-  Lacertilia, ii. 223
-
-  Lamarck, Jean, i. 111
-
-  Lamarck's anthropology, i. 115; ii. 264
-
-  ---- philosophy of nature, i. 112
-
-  ---- theory of descent, i. 113
-
-  Lamarckism, i. 150
-
-  Lamellibranchia, ii. 158, 160
-
-  Lancelet, ii. 198, 204, 285
-
-  Laplace's cosmogeny, i. 321
-
-  Laurentian system, ii. 9, 14
-
-  Lemuria, i. 361; ii. 326
-
-  Leonardo da Vinci, i. 56
-
-  Leptocardia, ii. 196, 204
-
-  Leucones, ii. 141
-
-  Linnæus, Charles, i. 39
-
-  Linnæus' classification of animals, ii. 118
-
-  ---- classification of plants, ii. 78
-
-  ---- designation of species, i. 41
-
-  ---- history of creation, i. 44
-
-  ---- system, i. 40
-
-  Lubbock, Sir John, ii. 298
-
-  Lyell, Charles, i. 126
-
-  Lyell's history of creation, i. 128
-
-
-  M
-
-  MAGYARS, ii. 309, 316
-
-  Malays, ii. 308, 315
-
-  Malthus' theory of population, i. 161
-
-  Mammalia, ii. 231, 239
-
-  Man-apes, ii. 271, 275, 292
-
-  Marsupials, ii. 236, 239, 290
-
-  Matagenesis, i. 206
-
-  Materialism, i. 35
-
-  Matter, i. 22; ii. 360
-
-  Mechanical causes, i. 34, 74
-
-  Mechanical conception of the universe, i. 17, 74
-
-  Mechanism, i. 37, 102
-
-  Mediterranese, ii. 308, 321
-
-  Medusæ, ii. 143, 144
-
-  Mesolithic period, ii. 14, 20
-
-  Metamorphosis of the earth's strata, ii. 25
-
-  Metamorphosis, i. 90
-
-  Migration, laws of, i. 373
-
-  ---- of organisms, i. 354
-
-  ---- of the human species, ii. 325
-
-  ---- theory of, i. 367
-
-  Mind, i. 22; ii. 360
-
-  ---- development of the, ii. 344, 360
-
-  Miocene period, ii. 15, 16
-
-  Miracles, i. 22
-
-  Molluscs, ii. 155, 160
-
-  Monera, i. 184, 343; ii. 52, 278
-
-  Mongols, ii. 308, 316
-
-  Monism, i. 34
-
-  Monistic conception of the universe, i. 20, 74
-
-  Monocottylæ, ii. 82, 112
-
-  Monoglottonic, ii. 327, 333
-
-  Monogony, i. 183
-
-  Monophylites, ii. 44
-
-  Monophyletic hypothesis of descent, ii. 44
-
-  Monorrhina, ii. 203, 204
-
-  Monosporogonia, i. 194
-
-  Monotrema, ii. 234, 239
-
-  Morphology, i. 21
-
-  Morula, ii. 125, 127
-
-  Moses' history of creation, i. 37
-
-  Moss animals, ii. 150, 152
-
-  Mosses, ii. 82, 97
-
-  Müller, Fritz, i. 49, 73; ii. 174
-
-  Müller, Johannes, i. 312; ii. 203
-
-  Muscinæ, ii. 82, 99
-
-  Mussels, ii. 159, 160
-
-  Myriapoda, ii. 182, 184
-
-  Myxomycetes, ii. 51, 60
-
-
-  N
-
-  NATURAL PHILOSOPHY, i. 78
-
-  Negroes, ii. 309, 313, 333
-
-  Nemathelminthes, ii. 149, 150
-
-  Newton, i. 25, 106
-
-  Non-amnionate, ii. 204, 209
-
-  Nubians, ii. 308, 320
-
-
-  O
-
-  OECOLOGY, ii. 354
-
-  Oken, Lorenz, i. 95
-
-  Oken's history of development, i. 293
-
-  ---- philosophy of nature, i. 96
-
-  ---- theory of infusoria, i. 97
-
-  ---- ---- protoplasm, i. 97
-
-  Olynthus, ii. 141
-
-  Ontogenesis, i. 293
-
-  Ontogeny, i. 10; ii. 33
-
-  Orang, ii. 271, 275
-
-  Organisms, i. 5, 328
-
-  Organs, i. 5
-
-  Origin of language, ii. 302, 327
-
-  Osseous fishes, ii. 208, 211
-
-  Ovularia, ii. 132, 134
-
-
-  P
-
-  PACHYCARDIA, ii. 201
-
-  Palæolithic period, ii. 11, 14
-
-  Palæontology, i. 54
-
-  Palissy, i. 56
-
-  Palm ferns, ii. 82, 110
-
-  Pander, Christian, i. 294
-
-  Papuans, ii. 310, 333
-
-  Paradise, ii. 325
-
-  Parallelism of development, i. 313
-
-  Parthenogenesis, i. 197
-
-  Pedigree of amphibia, ii. 209
-
-  ---- anamnia, ii. 209
-
-  ---- apes, ii. 270
-
-  Permean system, ii. 11, 14
-
-  Petrifactions, i. 54
-
-  Phanerogama, ii. 80, 82, 108
-
-  Philosophy, i. 79; ii. 350
-
-  Phylogeny, i. 10; ii. 33
-
-  Phylum, ii. 42
-
-  Physiology, i. 21
-
-  Pithecoid, theory, ii. 356
-
-  Placentalia, ii. 240, 244
-
-  Planula, ii. 126, 135, 281
-
-  Planæa, ii. 125, 127
-
-  Planæada, ii. 280
-
-  Plasma, i. 185, 330
-
-  Plasmogony, i. 339
-
-  Plastids, i. 347
-
-  Plastids, theory of, i. 347
-
-  Platyelminthes, ii. 148, 150
-
-  Platyrrhini, ii. 270, 272
-
-  Pleistocene system, ii. 15
-
-  Pliocene system, ii. 15, 16
-
-  Polar man, ii. 308, 317
-
-  Polyglottal, ii. 327, 333
-
-  Polynesians, ii. 308, 315
-
-  Polyphyletic theory of descent, ii. 45
-
-  Polyphylites, ii. 45, 303
-
-  Polyps, ii. 142
-
-  Polyp jellies, ii. 143, 144
-
-  Polysporogonia, i. 193
-
-  Population, number of, ii. 333
-
-  Porifera, ii. 139, 144
-
-  Primary mammals, ii. 239, 290
-
-  Primary period, ii. 11, 14
-
-  Primæval algæ, ii. 82, 84
-
-  ---- animals, ii. 131, 132
-
-  ---- history of man, ii. 298
-
-  ---- men, ii. 325
-
-  Primordial period, ii. 9, 14
-
-  Prochordata, ii. 278
-
-  Progenitors of man, ii. 279, 295
-
-  Progress, i. 277, 283
-
-  Promammalia, ii. 233, 239
-
-  Propagation, i. 183
-
-  ---- amphigonic, i. 195
-
-  ---- monogonic, i. 183
-
-  ---- non-sexual, i. 183
-
-  Propagation, sexual, i. 195
-
-  ---- virginal, i. 197
-
-  Protamnia, ii. 289, 295
-
-  Protamoebæ, ii. 52
-
-  Prothallophytes, ii. 80, 97
-
-  Prothallus plants, ii. 80, 97
-
-  Protista, ii. 48
-
-  Protophyta, ii. 82, 85
-
-  Protoplasma, i. 185, 330
-
-  Protoplasts, ii. 51, 53
-
-  Protozoa, ii. 121, 131, 132
-
-  Purpose in nature, i. 19
-
-  Purposelessness in nature, i. 20
-
-
-  R
-
-  RADIATA, ii. 120
-
-  Radiolaria, i. 333, 371; ii. 65
-
-  Rapacious animals, ii. 240, 260
-
-  Recent system, ii. 15
-
-  Reptiles, ii. 222, 224
-
-  Rhizopoda, ii. 51, 61
-
-  Ringed worms, ii. 149, 150
-
-  Rodentia, ii. 241, 257
-
-  Romans, ii. 323, 331
-
-  Rotatoria, ii. 149, 150
-
-  Rotifera, ii. 150, 152
-
-  Round worms, ii. 149, 150
-
-  Rudimentary eyes, i. 13
-
-  ---- gristle, i. 12
-
-  ---- legs, i. 14
-
-  ---- lungs, i. 289
-
-  ---- mammary glands, i. 290
-
-  ---- muscles, i. 12
-
-  ---- nictitating membrane, i. 13
-
-  ---- organs, i. 12
-
-  ---- pistils, i. 15
-
-  ---- stamens, i. 15
-
-  ---- tails, i. 289
-
-  ---- teeth, i. 12
-
-  ---- wings, i. 287
-
-
-  S
-
-  SACK WORMS, ii. 283, 295
-
-  Sauria, ii. 222
-
-  Schaaffhausen, i. 110
-
-  Schleicher, August, i. 108; ii. 301
-
-  Schleiden, J. M., i. 109
-
-  Science, i. 9; ii. 335
-
-  Scolecida, ii. 283, 295
-
-  Sea stars, ii. 164, 166
-
-  ---- cucumbers, ii. 166, 171
-
-  Sea dragons, ii. 204
-
-  ---- lilies, ii. 166, 177
-
-  ---- nettles, ii. 141, 144
-
-  ---- urchins, ii. 166, 171
-
-  Secondary period, ii. 14, 20
-
-  Selection æsthetic, i. 268
-
-  ---- artificial, i. 152, 170, 254
-
-  ---- homochromic, i. 263
-
-  ---- medical, i. 173
-
-  ---- military, i. 171
-
-  ---- musical, i. 267
-
-  ---- natural, i. 168, 255
-
-  ---- psychical, i. 269
-
-  ---- sexual, i. 265
-
-  ---- Spartan, i. 170
-
-  Self-division, i. 191
-
-  Semites, ii. 322, 330
-
-  Serpents, ii. 223
-
-  Sexes, separation of, i. 244
-
-  Sexual characters, i. 209, 265
-
-  Silurian system, ii. 8, 14
-
-  Slavonians, ii. 323, 331
-
-  Snails, ii. 159, 160
-
-  Soul, the, i. 71; ii. 343, 362
-
-  Species, i. 41, 273, 304, 311
-
-  Specific development, i. 311
-
-  Spencer, Herbert, i. 119; ii. 367
-
-  Sperma, i. 197
-
-  Spiders, i. 180, 182
-
-  Spirobranchia, ii. 157, 160
-
-  Sponges, ii. 139, 144
-
-  Spores, formation of, i. 194
-
-  Stemmed plants, ii. 280
-
-  Straight-haired men, ii. 309, 314
-
-  Struggle for life, i. 161, 252
-
-  Synamoeba, ii. 125, 280
-
-  Systematic development, i. 313
-
-  System of animals, ii. 132
-
-  ---- apes, ii. 270
-
-  ---- Arabians, ii. 330
-
-  ---- arachnida, ii. 182
-
-  ---- Arians, ii. 331
-
-  ---- arthropoda, ii. 132
-
-  ---- articulata, ii. 177, 183
-
-  ---- catarrhini, ii. 270
-
-  ---- coelenterata, ii. 144
-
-  ---- crustacea, ii. 176
-
-  ---- didelphia, ii. 239
-
-  ---- echinoderma, ii. 166
-
-  ---- Egyptians, ii. 330
-
-  ---- fishes, ii. 208
-
-  ---- formations, ii. 15
-
-  ---- Germans, ii. 331
-
-  ---- gilled Insects, ii. 177
-
-  ---- Græco-Romans, ii. 331
-
-  ---- Hamites, ii. 330
-
-  ---- hoofed animals, ii. 252
-
-  ---- human ancestors, ii. 295
-
-  ---- human races, ii. 308
-
-  ---- human species, ii. 308, 309
-
-  ---- Indians, ii. 331
-
-  ---- Indo-Germani, ii. 331
-
-  ---- insects, ii. 182
-
-  ---- mammalia, ii. 239
-
-  ---- mankind, ii. 295
-
-  ---- marsupials, ii. 239
-
-  ---- men and apes, ii. 271
-
-  ---- molluscs, ii. 160
-
-  ---- monodelphia, ii. 241
-
-  ---- organisms, ii. 74, 75
-
-  ---- placentalia, ii. 240
-
-  ---- plants, ii. 82
-
-  ---- platyrrhini, ii. 270
-
-  ---- protista, ii. 51
-
-  ---- reptiles, ii. 224
-
-  ---- Semites, ii. 330
-
-  ---- Slavonians, ii. 331
-
-  ---- spiders, ii. 182
-
-  ---- star fishes, ii. 167
-
-  ---- strata of the earth, ii. 15
-
-  ---- tracheata, ii. 182
-
-  ---- ungulata, ii. 252
-
-  ---- vegetable kingdom, ii. 83
-
-  ---- vertebrata, ii. 204
-
-  ---- worms, ii. 150
-
-  ---- zoophytes, ii. 144
-
-
-  T
-
-  TAIL OF MAN, i. 289, 308
-
-  Tangles, ii. 61, 82
-
-  Tartars, ii. 209, 317
-
-  Teleology, i. 100, 291
-
-  Teleostei, ii. 208, 211
-
-  Teleological conception of the universe, i. 20, 75
-
-  Tertiary period, ii. 14, 16
-
-  Thallophytes, ii. 80, 82
-
-  Thickness of the earth's crust, ii. 19
-
-  Thought, ii. 364
-
-  Thread plants, ii. 82, 93
-
-  Tocogony, i. 183
-
-  Tortoises, ii. 225
-
-  Tracheata, ii. 182
-
-  Transition forms, ii. 338
-
-  Transmutation, theory of, i. 4
-
-  Treviranus, i. 92
-
-  Trias system, ii. 12, 14
-
-  Tuft-haired men, ii. 307, 309
-
-  Tunicata, ii. 152, 200
-
-  Turbellaria, ii. 283
-
-  Turks, ii. 309, 316
-
-
-  U
-
-  UNGER, FRANZ, i. 109
-
-  Ungulata, ii. 249, 252
-
-  Unity in nature, i. 22, 338
-
-  Uralians, ii. 309, 317
-
-
-  V
-
-  Variability, i. 220
-
-  Variation, i. 219
-
-  Varieties, i. 276
-
-  Vertebrata, ii. 195, 205
-
-  Vital force, i. 22, 334
-
-  Vitalistic conception of the universe, i. 18
-
-
-  W
-
-  Wagner, Andreas, i. 138
-
-  Wagner, Moritz, i. 369
-
-  Wallace, Alfred, i. 135
-
-  Wallace's chorology, i. 361, 373
-
-  ---- theory of selection, i. 136
-
-  Well's theory of selection, i. 150
-
-  Whales, ii. 240, 251
-
-  Will, freedom of the, i. 113, 237, 364
-
-  Wolff's theory of development, i. 293
-
-  Woolly-haired men, ii. 307, 309
-
-  Worms, ii. 147, 150
-
-
-  Z
-
-  ZOOPHYTES, ii. 136, 144
-
-
-
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       The Project Gutenberg eBook of The History of Creation Vol. II. by Ernst Haeckel
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-<pre>
-
-Project Gutenberg's The History of Creation, Vol. II (of 2), by Ernst Haeckel
-
-This eBook is for the use of anyone anywhere at no cost and with
-almost no restrictions whatsoever.  You may copy it, give it away or
-re-use it under the terms of the Project Gutenberg License included
-with this eBook or online at www.gutenberg.org
-
-
-Title: The History of Creation, Vol. II (of 2)
-       Or the Development of the Earth and its Inhabitants by the
-              Action of Natural Causes
-
-Author: Ernst Haeckel
-
-Translator: E. Ray Lankester
-
-Release Date: August 14, 2012 [EBook #40473]
-
-Language: English
-
-Character set encoding: ISO-8859-1
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-*** START OF THIS PROJECT GUTENBERG EBOOK HISTORY OF CREATION, VOL II ***
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+<div>*** START OF THE PROJECT GUTENBERG EBOOK 40473 ***</div>
 
 <div class="box">
 Transcriber&#8217;s note:
@@ -1334,7 +1292,7 @@ Organic History of the Earth.</i></td>
 <td class="left">&nbsp;</td>
 </tr>
 <tr>
-<td class="center" rowspan="7">IV. <i>Tertiary<br />Group</i>,<br />or<br />(Cænozoic)<br />groups of strata.</td>
+<td class="center" rowspan="7">IV. <i>Tertiary<br />Group</i>,<br />or<br />(Cænozoic)<br />groups of strata.</td>
 <td class="center" rowspan="7"><div class="figcenter" style="width: 10px;"><img src="images/cb100.png" width="10" height="100" alt=
 "{" /></div></td>
 <td class="center" rowspan="2">XII. Pliocene<br />(Late tertiary)</td>
@@ -1457,7 +1415,7 @@ Organic History of the Earth.</i></td>
 <td class="left">&nbsp;</td>
 </tr>
 <tr>
-<td class="center" rowspan="7">II. <i>Primary<br />Group</i>,<br />or<br />Palæolithic<br />(Palæozoic)<br />groups of strata</td>
+<td class="center" rowspan="7">II. <i>Primary<br />Group</i>,<br />or<br />Palæolithic<br />(Palæozoic)<br />groups of strata</td>
 <td class="center" rowspan="7"><div class="figcenter" style="width: 10px;"><img src="images/cb150.png" width="10" height="150" alt=
 "{" /></div></td>
 <td class="left" rowspan="2">VI. Permian</td>
@@ -2777,15 +2735,15 @@ the next page, and their general natural history.</p>
 <td class="leftm padt1 smcap" colspan="2" rowspan="3">2. Protoplasts</td>
 <td class="left vertm padt1" rowspan="3">Am&oelig;boida</td>
 <td class="center padt1" rowspan="3"><div class="figcenter" style="width: 10px;"><img src="images/cb50.png" width="10" height="50" alt="{" /></div></td>
-<td class="left padt1">1. Gymnam&oelig;bæ</td>
+<td class="left padt1">1. Gymnam&oelig;bæ</td>
 <td class="left padt1">Am&oelig;ba</td>
 </tr>
 <tr>
-<td class="left">2. Leptam&oelig;bæ</td>
+<td class="left">2. Leptam&oelig;bæ</td>
 <td class="left">Arcella</td>
 </tr>
 <tr>
-<td class="left">3. Gregarinæ</td>
+<td class="left">3. Gregarinæ</td>
 <td class="left">Monocystis</td>
 </tr>
 <tr>
@@ -2807,13 +2765,13 @@ the next page, and their general natural history.</p>
 <td class="left vertm padt1">Catallacta</td>
 <td class="center">&nbsp;</td>
 <td class="left padt1">1. Catallacta</td>
-<td class="left padt1">Magosphæra</td>
+<td class="left padt1">Magosphæra</td>
 </tr>
 <tr>
 <td class="left padt1 vertm smcap" colspan="2">5. Tram-weavers</td>
-<td class="left padt1 vertm">Labyrinthuleæ</td>
+<td class="left padt1 vertm">Labyrinthuleæ</td>
 <td class="center">&nbsp;</td>
-<td class="left padt1">1. Labyrinthuleæ</td>
+<td class="left padt1">1. Labyrinthuleæ</td>
 <td class="left padt1">Labyrinthula</td>
 </tr>
 <tr>
@@ -2835,19 +2793,19 @@ the next page, and their general natural history.</p>
 <td class="left padt1 vertm smcap" colspan="2" rowspan="4">7. Slime-moulds</td>
 <td class="left padt1 vertm" rowspan="4">Myxomycetes</td>
 <td class="center padt1" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb75.png" width="10" height="75" alt="{" /></div></td>
-<td class="left padt1">1. Physareæ</td>
-<td class="left padt1">Æthalium</td>
+<td class="left padt1">1. Physareæ</td>
+<td class="left padt1">Æthalium</td>
 </tr>
 <tr>
-<td class="left">2. Stemoniteæ</td>
+<td class="left">2. Stemoniteæ</td>
 <td class="left">Stemonitis</td>
 </tr>
 <tr>
-<td class="left">3. Trichiaceæ</td>
+<td class="left">3. Trichiaceæ</td>
 <td class="left">Arcyria</td>
 </tr>
 <tr>
-<td class="left">4. Lycogaleæ</td>
+<td class="left">4. Lycogaleæ</td>
 <td class="left">Reticularia</td>
 </tr>
 <tr>
@@ -2867,17 +2825,17 @@ the next page, and their general natural history.</p>
 <td class="left padt1 vertm">II. Heliozoa</td>
 <td class="center">&nbsp;</td>
 <td class="left padt1">1. Heliozoa</td>
-<td class="left padt1">Actinosphærium</td>
+<td class="left padt1">Actinosphærium</td>
 </tr>
 <tr>
 <td class="left vertm" rowspan="2">III. Radiolaria</td>
 <td class="center padt1" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="left padt1">1. Monocyttaria</td>
-<td class="left padt1">Cyrtidosphæra</td>
+<td class="left padt1">Cyrtidosphæra</td>
 </tr>
 <tr>
 <td class="left">2. Polycyttaria</td>
-<td class="left">Collosphæra</td>
+<td class="left">Collosphæra</td>
 </tr>
 
 </table>
@@ -3635,7 +3593,7 @@ designation of independent Protista.</p>
 <table class="pedigree" style="font-size: .85em;" summary="kingdoms" border="0">
 
 <tr>
-<td class="center">II.<br /><span class="oldtype">Vegetable Kingdom</span><br /><b>Plantæ</b></td>
+<td class="center">II.<br /><span class="oldtype">Vegetable Kingdom</span><br /><b>Plantæ</b></td>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="4">III.<br /><span class="oldtype">Animal Kingdom</span><br /><b>Animalia</b></td>
 </tr>
@@ -3664,7 +3622,7 @@ designation of independent Protista.</p>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
-<td class="center">Ferns<br /><i>Filicinæ</i><br />&#9474;<br /></td>
+<td class="center">Ferns<br /><i>Filicinæ</i><br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 <td class="center">Star-fishes<br /><i>Echinoderma</i><br /><div class="figcenter" style="width: 75px;"><img src="images/cb75h.png" width="75" height="10" alt="-------------" /></div></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
@@ -3688,7 +3646,7 @@ designation of independent Protista.</p>
 <td class="center">&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center">Mosses<br /><i>Muscinæ</i></td>
+<td class="center">Mosses<br /><i>Muscinæ</i></td>
 <td class="center">Lichens<br /><i>Lichenes</i></td>
 <td class="center" colspan="4"><div class="figcenter" style="width: 400px;"><img src="images/cb400h.png" width="400" height="10" alt="--------------------------------------------------------------------" /></div></td>
 </tr>
@@ -3712,7 +3670,7 @@ designation of independent Protista.</p>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center"><i>Algæ</i></td>
+<td class="center"><i>Algæ</i></td>
 <td class="center">Fungi<br /><i>Fungi</i></td>
 <td class="center" colspan="2">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
@@ -3738,9 +3696,9 @@ designation of independent Protista.</p>
 <td class="center" colspan="2"><div class="figcenter" style="width: 150px;"><img src="images/cb150h.png" width="150" height="10" alt="------------------------" /></div></td>
 </tr>
 <tr>
-<td class="center" colspan="2"><span class="oldtype">Primæval Plants</span><br /><b>Protophyta</b></td>
-<td class="center" colspan="2"><span class="oldtype">Neutral<br />Primæval Creatures</span><br /><b>Protista</b></td>
-<td class="center" colspan="2"><span class="oldtype">Primæval Animals</span><br /><b>Protozoa</b></td>
+<td class="center" colspan="2"><span class="oldtype">Primæval Plants</span><br /><b>Protophyta</b></td>
+<td class="center" colspan="2"><span class="oldtype">Neutral<br />Primæval Creatures</span><br /><b>Protista</b></td>
+<td class="center" colspan="2"><span class="oldtype">Primæval Animals</span><br /><b>Protozoa</b></td>
 </tr>
 <tr>
 <td class="center" colspan="2"><div class="figcenter" style="width: 100px;"><img src="images/cb100h.png" width="100" height="10" alt="-----------------" /></div></td>
@@ -3835,7 +3793,7 @@ designation of independent Protista.</p>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 
 <td class="center">&nbsp;</td>
-<td class="center" colspan="6">Flint-cells<br /><i>Diatomæ</i><br /><div class="figcenter" style="width: 50px;">
+<td class="center" colspan="6">Flint-cells<br /><i>Diatomæ</i><br /><div class="figcenter" style="width: 50px;">
 <img src="images/cb50h.png" alt="-------------" height="10" width="50" /></div></td>
 <td class="center" colspan="7">&nbsp;</td>
 <td class="center" colspan="6">&nbsp;</td>
@@ -3894,19 +3852,19 @@ designation of independent Protista.</p>
 <td class="center">&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center" colspan="10"><span class="oldtype">Primæval Plants</span><br /><b>Protophyta</b></td>
+<td class="center" colspan="10"><span class="oldtype">Primæval Plants</span><br /><b>Protophyta</b></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="3">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="3">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
-<td class="center" colspan="7">Am&oelig;bæ<br />or<br />Protoplasta</td>
+<td class="center" colspan="7">Am&oelig;bæ<br />or<br />Protoplasta</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="2">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="3">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
-<td class="center" colspan="11"><span class="oldtype">Primæval<br />Animals</span><br /><b>Protozoa</b></td>
+<td class="center" colspan="11"><span class="oldtype">Primæval<br />Animals</span><br /><b>Protozoa</b></td>
 </tr>
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
@@ -4609,7 +4567,7 @@ exist at all.</p>
 </tr>
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center"><i>Gamopetalæ</i><br />(Flowers with corolla)</td>
+<td class="center"><i>Gamopetalæ</i><br />(Flowers with corolla)</td>
 <td class="center" colspan="2">&nbsp;</td>
 </tr>
 <tr>
@@ -4619,7 +4577,7 @@ exist at all.</p>
 </tr>
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center"><i>Dialypetalæ</i><br />(Star-shaped flowers)</td>
+<td class="center"><i>Dialypetalæ</i><br />(Star-shaped flowers)</td>
 <td class="center" colspan="2">&nbsp;</td>
 </tr>
 <tr>
@@ -4629,8 +4587,8 @@ exist at all.</p>
 </tr>
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center"><i>Monochlamydeæ</i><br />(Flowers with calyx)</td>
-<td class="center"><span class="smcap">Monocotyledonæ</span><br />(One seed-lobed plants)</td>
+<td class="center"><i>Monochlamydeæ</i><br />(Flowers with calyx)</td>
+<td class="center"><span class="smcap">Monocotyledonæ</span><br />(One seed-lobed plants)</td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
@@ -4641,7 +4599,7 @@ exist at all.</p>
 </tr>
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center"><span class="smcap">Dicotyledonæ</span><br />(Two seed-lobed plants)</td>
+<td class="center"><span class="smcap">Dicotyledonæ</span><br />(Two seed-lobed plants)</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 </tr>
@@ -4658,10 +4616,10 @@ exist at all.</p>
 </tr>
 
 <tr>
-<td class="center"><span class="smcap">Cycadeæ</span><br />(Palm-ferns)</td>
-<td class="center"><span class="smcap">Coniferæ</span><br />(Pines)</td>
-<td class="center"><span class="smcap">Gnetaceæ</span></td>
-<td class="center" colspan="2"><b>Angiospermæ</b><br />(Plants with enclosed seeds)</td>
+<td class="center"><span class="smcap">Cycadeæ</span><br />(Palm-ferns)</td>
+<td class="center"><span class="smcap">Coniferæ</span><br />(Pines)</td>
+<td class="center"><span class="smcap">Gnetaceæ</span></td>
+<td class="center" colspan="2"><b>Angiospermæ</b><br />(Plants with enclosed seeds)</td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
@@ -4679,18 +4637,18 @@ exist at all.</p>
 </tr>
 
 <tr>
-<td class="center padr6" colspan="5"><b>Gymnospermæ</b><br />(Plants with naked seeds)</td>
+<td class="center padr6" colspan="5"><b>Gymnospermæ</b><br />(Plants with naked seeds)</td>
 <td class="center">&nbsp;</td>
 
 </tr>
 
 <tr>
-<td class="center"><i>Selagineæ</i><br />(Scaled-ferns)</td>
-<td class="center"><i>Rhizocarpeæ</i><br />(Water-ferns)</td>
+<td class="center"><i>Selagineæ</i><br />(Scaled-ferns)</td>
+<td class="center"><i>Rhizocarpeæ</i><br />(Water-ferns)</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
-<td class="center"><i>Phanerogamæ</i><br />Flowering plants</td>
-<td class="center"><i>Pterideæ</i><br />(Frondose-ferns)</td>
-<td class="center"><i>Calamariæ</i><br />(Shaft-ferns)</td>
+<td class="center"><i>Phanerogamæ</i><br />Flowering plants</td>
+<td class="center"><i>Pterideæ</i><br />(Frondose-ferns)</td>
+<td class="center"><i>Calamariæ</i><br />(Shaft-ferns)</td>
 
 </tr>
 <tr>
@@ -4711,13 +4669,13 @@ exist at all.</p>
 
 <tr>
 <td class="center">&nbsp;</td>
-<td class="center padr4" colspan="5"><b>Filicinæ</b><br />(Ferns)</td>
+<td class="center padr4" colspan="5"><b>Filicinæ</b><br />(Ferns)</td>
 
 </tr>
 
 <tr>
-<td class="center" colspan="2"><i>Frondosæ</i><br />(Leaf-mosses)</td>
-<td class="center"><i>Sphagnaceæ</i><br />(Turf-mosses)</td>
+<td class="center" colspan="2"><i>Frondosæ</i><br />(Leaf-mosses)</td>
+<td class="center"><i>Sphagnaceæ</i><br />(Turf-mosses)</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="2">&nbsp;</td>
 </tr>
@@ -4730,13 +4688,13 @@ exist at all.</p>
 
 <tr>
 <td class="center padl2" colspan="4"><div class="figcenter" style="width: 300px;"><img src="images/cb300h.png" width="300" height="10" alt="---------------------------------------------" /></div></td>
-<td class="center"><span class="smcap">Characeæ</span><br />(Tangle-mosses)</td>
+<td class="center"><span class="smcap">Characeæ</span><br />(Tangle-mosses)</td>
 <td class="center">&nbsp;</td>
 
 </tr>
 
 <tr>
-<td class="center" colspan="4"><i>Hepaticæ</i><br />(Liverworts)</td>
+<td class="center" colspan="4"><i>Hepaticæ</i><br />(Liverworts)</td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 
@@ -4754,15 +4712,15 @@ exist at all.</p>
 </tr>
 
 <tr>
-<td class="center padl2" colspan="6"><b>Muscinæ</b><br />(Mosses)</td>
+<td class="center padl2" colspan="6"><b>Muscinæ</b><br />(Mosses)</td>
 
 </tr>
 
 <tr>
 <td class="center">&nbsp;</td>
-<td class="center"><i>Florideæ</i><br />(Red Algæ)</td>
-<td class="center"><i>Fucoideæ</i><br />(Brown Algæ)</td>
-<td class="center"><i>Chlorophyceæ</i><br />(Green Algæ)</td>
+<td class="center"><i>Florideæ</i><br />(Red Algæ)</td>
+<td class="center"><i>Fucoideæ</i><br />(Brown Algæ)</td>
+<td class="center"><i>Chlorophyceæ</i><br />(Green Algæ)</td>
 <td class="center"><i>Lichenes</i><br />(Lichens)</td>
 <td class="center">&nbsp;</td>
 
@@ -4785,7 +4743,7 @@ exist at all.</p>
 
 <tr>
 <td class="center">&nbsp;</td>
-<td class="center" colspan="3"><b>Algæ</b><br />(Tangles)</td>
+<td class="center" colspan="3"><b>Algæ</b><br />(Tangles)</td>
 <td class="center"><b>Fungi Inophyta</b><br />(Thread-plants)</td>
 <td class="center">&nbsp;</td>
 
@@ -4807,7 +4765,7 @@ exist at all.</p>
 
 <tr>
 <td class="center" colspan="2">&nbsp;</td>
-<td class="center" colspan="3"><i>Protophyta</i> (Primæval Plants)</td>
+<td class="center" colspan="3"><i>Protophyta</i> (Primæval Plants)</td>
 <td class="center">&nbsp;</td>
 
 </tr>
@@ -6318,13 +6276,13 @@ see also in the same place the Ascidian, Fig. <i>A</i> 4).</p>
 <tr>
 <td class="center padl1 padr1 "><i>Second Stage of Development.</i></td>
 <td class="center vertt padl1 padr1 bl"><b>2.</b><br /><b>Ovulum.</b></td>
-<td class="center vertt padl1 padr1 bl"><b>2.</b><br /><b>Am&oelig;bæ.</b></td>
+<td class="center vertt padl1 padr1 bl"><b>2.</b><br /><b>Am&oelig;bæ.</b></td>
 </tr>
 
 <tr>
 <td class="just vertt">A simple cell (a plastid containing a kernel.)</td>
 <td class="just vertt padl1 padr1 bl">Animal egg with kernel (a simple egg-cell).</td>
-<td class="center vertt padl1 padr1 bl">Animal Am&oelig;bæ.</td>
+<td class="center vertt padl1 padr1 bl">Animal Am&oelig;bæ.</td>
 </tr>
 
 <tr>
@@ -6342,7 +6300,7 @@ see also in the same place the Ascidian, Fig. <i>A</i> 4).</p>
 <tr>
 <td class="just vertt padl1 padr1">A community (an aggregation of identical simple cells).</td>
 <td class="just vertt padl1 padr1 bl">Globular heap of homogeneous &#8220;cleavage spheres.&#8221;</td>
-<td class="just vertt padl1 padr1 bl">An aggregation of Am&oelig;bæ.</td>
+<td class="just vertt padl1 padr1 bl">An aggregation of Am&oelig;bæ.</td>
 </tr>
 
 <tr>
@@ -6354,13 +6312,13 @@ see also in the same place the Ascidian, Fig. <i>A</i> 4).</p>
 <tr>
 <td class="center padl1 padr1"><i>Fourth Stage of Development.</i></td>
 <td class="center vertt padl1 padr1 bl"><b>4.</b><br /><b>Planula.</b><br />(<i>Ciliated larva</i>.)</td>
-<td class="center vertt padl1 padr1 bl"><b>4.</b><br /><b>Planæa.</b></td>
+<td class="center vertt padl1 padr1 bl"><b>4.</b><br /><b>Planæa.</b></td>
 </tr>
 
 <tr>
 <td class="just vertt padl1 padr1">A solid or bladder-shaped, globular, or oval body, <i>composed of two kinds of different cells:</i> externally ciliated, internally non-ciliated cells.</td>
 <td class="just vertt padl1 padr1 bl">Many-celled larva without mouth, composed of different cells.</td>
-<td class="just vertt padl1 padr1 bl">Many-celled primæval animal without mouth, composed of two kinds of different cells.</td>
+<td class="just vertt padl1 padr1 bl">Many-celled primæval animal without mouth, composed of two kinds of different cells.</td>
 </tr>
 
 <tr>
@@ -6372,7 +6330,7 @@ see also in the same place the Ascidian, Fig. <i>A</i> 4).</p>
 <tr>
 <td class="center padl1 padr1"><i>Fifth Stage of Development.</i></td>
 <td class="center vertt padl1 padr1 bl"><b>5.</b><br /><b>Gastrula.</b><br />(<i>Larva with mouth.</i>)</td>
-<td class="center vertt padl1 padr1 bl"><b>5.</b><br /><b>Gastræa.</b></td>
+<td class="center vertt padl1 padr1 bl"><b>5.</b><br /><b>Gastræa.</b></td>
 </tr>
 
 <tr>
@@ -6380,7 +6338,7 @@ see also in the same place the Ascidian, Fig. <i>A</i> 4).</p>
 Body wall composed of two layers</i>; an externally ciliated ectoderm (dermal layer), an
 internally non-ciliated entoderm (gastral layer).</td>
 <td class="just vertt padl1 padr1 bl">Many-celled with intestines and mouth; intestinal wall with two layers.</td>
-<td class="just vertt padl1 padr1 bl">Many-celled primæval animal with intestine and mouth; intestinal wall with two layers. (Primary form of zoophytes and worms.)</td>
+<td class="just vertt padl1 padr1 bl">Many-celled primæval animal with intestine and mouth; intestinal wall with two layers. (Primary form of zoophytes and worms.)</td>
 </tr>
 </table>
 
@@ -6547,7 +6505,7 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 </tr>
 
 <tr>
-<td class="center" rowspan="6">A.<br /><span class="oldtype">Primæval<br />Animals</span><br /><b>Protozoa</b></td>
+<td class="center" rowspan="6">A.<br /><span class="oldtype">Primæval<br />Animals</span><br /><b>Protozoa</b></td>
 <td class="center" rowspan="6"><div class="figcenter" style="width: 10px;"><img src="images/cb50.png" width="10" height="50" alt="{" /></div></td>
 <td class="center" rowspan="4">I. Egg-animals<br /><i>Ovularia</i></td>
 <td class="center padt1" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
@@ -6560,7 +6518,7 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 <td class="right">2.</td>
 <td class="left">Gregarines</td>
 <td class="right">2.</td>
-<td class="left">Gregarinæ</td>
+<td class="left">Gregarinæ</td>
 </tr>
 <tr>
 <td class="right">3.</td>
@@ -6575,20 +6533,20 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 <td class="center" rowspan="2">II. Mulberry animals<br /><i>Ovularia</i></td>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb20.png" width="10" height="20" alt="{" /></div></td>
 <td class="right">4.</td>
-<td class="left">Planæads</td>
+<td class="left">Planæads</td>
 <td class="right">4.</td>
-<td class="left">Planæadas</td>
+<td class="left">Planæadas</td>
 </tr>
 <tr>
 <td class="right">5.</td>
-<td class="left">Gastræads</td>
+<td class="left">Gastræads</td>
 <td class="right">5.</td>
-<td class="left">Gastræadas</td>
+<td class="left">Gastræadas</td>
 </tr>
 <tr>
 <td class="center" rowspan="4">B.<br /><span class="oldtype">Animal<br />Plants</span><br /><b>Zoophyta</b></td>
 <td class="center" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb50.png" width="10" height="50" alt="{" /></div></td>
-<td class="center padt05 padb05">III. Sponges<br /><i>Spongiæ</i></td>
+<td class="center padt05 padb05">III. Sponges<br /><i>Spongiæ</i></td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb20.png" width="10" height="20" alt="{" /></div></td>
 <td class="rightm">6.</td>
 <td class="left vertm">Sponges</td>
@@ -6596,7 +6554,7 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 <td class="left vertm">Porifera</td>
 </tr>
 <tr>
-<td class="center" rowspan="3">IV. Sea-nettles<br /><i>Acalephæ</i></td>
+<td class="center" rowspan="3">IV. Sea-nettles<br /><i>Acalephæ</i></td>
 <td class="center" rowspan="3"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="right">7.</td>
 <td class="left">Corals</td>
@@ -6607,7 +6565,7 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 <td class="right">8.</td>
 <td class="left">Hood-jellies</td>
 <td class="right">8.</td>
-<td class="left">Hydromedusæ</td>
+<td class="left">Hydromedusæ</td>
 </tr>
 <tr>
 <td class="right">9.</td>
@@ -6742,7 +6700,7 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 <td class="right">25.</td>
 <td class="left">Sea-cucumbers</td>
 <td class="right">25.</td>
-<td class="left">Holothuriæ</td>
+<td class="left">Holothuriæ</td>
 </tr>
 <tr>
 <td colspan="8">&nbsp;</td>
@@ -6972,8 +6930,8 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 </tr>
 <tr>
 <td class="center">&nbsp;</td>
-<td class="center">Spongiæ</td>
-<td class="center">Acalephæ</td>
+<td class="center">Spongiæ</td>
+<td class="center">Acalephæ</td>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="2">&#9474;<br /></td>
 <td class="center" colspan="3">&nbsp;</td>
@@ -7022,7 +6980,7 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 <td class="center">&nbsp;</td>
 <td class="center padr2" colspan="2">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
-<td class="center"><b>Protozoa</b><br />(<i>Primæval<br />animals</i>)</td>
+<td class="center"><b>Protozoa</b><br />(<i>Primæval<br />animals</i>)</td>
 <td class="center" colspan="4">&nbsp;</td>
 </tr>
 <tr>
@@ -7033,7 +6991,7 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 <tr>
 
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center"><b><span class="smcap">Gastræa</span></b></td>
+<td class="center"><b><span class="smcap">Gastræa</span></b></td>
 <td class="center" colspan="5">&nbsp;</td>
 </tr>
 <tr>
@@ -7045,9 +7003,9 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 </tr>
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center"><b><span class="smcap">Planæa</span></b></td>
+<td class="center"><b><span class="smcap">Planæa</span></b></td>
 <td class="center">&#9474;<br /></td>
-<td class="center">Gregarinæ</td>
+<td class="center">Gregarinæ</td>
 <td class="center" colspan="3">&nbsp;</td>
 
 </tr>
@@ -7062,7 +7020,7 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center"><b><span class="smcap">Synam&oelig;bæ</span></b></td>
+<td class="center"><b><span class="smcap">Synam&oelig;bæ</span></b></td>
 
 <td class="center" colspan="2"><div class="figcenter" style="width: 150px;"><img src="images/cb150h.png" width="150" height="10" alt="------------------------" /></div></td>
 <td class="center" colspan="3">&nbsp;</td>
@@ -7088,7 +7046,7 @@ the two classes of Plan&aelig;ads and Gastr&aelig;ads.</p>
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
 
-<td class="center padl2" colspan="2"><b><span class="smcap">Am&oelig;bæ</span></b></td>
+<td class="center padl2" colspan="2"><b><span class="smcap">Am&oelig;bæ</span></b></td>
 <td class="center" colspan="4">&nbsp;</td>
 </tr>
 <tr>
@@ -7463,9 +7421,9 @@ and eightfold have developed as two diverging branches.</p>
 </tr>
 
 <tr>
-<td class="center pad05" rowspan="8">I.<br /><span class="oldtype">Sponges</span><br /><b>Spongiæ</b><br />or<br /><b>Porifera</b></td>
+<td class="center pad05" rowspan="8">I.<br /><span class="oldtype">Sponges</span><br /><b>Spongiæ</b><br />or<br /><b>Porifera</b></td>
 <td class="center" rowspan="8"><div class="figcenter" style="width: 10px;"><img src="images/cb125.png" width="10" height="125" alt="{" /></div></td>
-<td class="center padl1 padr1" rowspan="2">I. Myxospongiæ<br /><i>Mucous Sponges</i></td>
+<td class="center padl1 padr1" rowspan="2">I. Myxospongiæ<br /><i>Mucous Sponges</i></td>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="rightt padt1">1.</td>
 <td class="left padt1">Archispongina</td>
@@ -7478,7 +7436,7 @@ and eightfold have developed as two diverging branches.</p>
 </tr>
 
 <tr>
-<td class="center" rowspan="3">II. Fibrospongiæ<br /><i>Fibrous Sponges</i></td>
+<td class="center" rowspan="3">II. Fibrospongiæ<br /><i>Fibrous Sponges</i></td>
 <td class="center padb05" rowspan="3"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="rightt">3.</td>
 <td class="left">Chalynthina</td>
@@ -7496,7 +7454,7 @@ and eightfold have developed as two diverging branches.</p>
 </tr>
 
 <tr>
-<td class="center padb1" rowspan="3">III. Calcispongiæ<br /><i>Calcareous Sponges</i></td>
+<td class="center padb1" rowspan="3">III. Calcispongiæ<br /><i>Calcareous Sponges</i></td>
 <td class="center padb05" rowspan="3"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="rightt">6.</td>
 <td class="left">Ascones</td>
@@ -7537,7 +7495,7 @@ and eightfold have developed as two diverging branches.</p>
 <tr>
 <td class="rightt">12.</td>
 <td class="left">Madreporaria</td>
-<td class="left bl padl05">Astræa</td>
+<td class="left bl padl05">Astræa</td>
 </tr>
 <tr>
 <td class="rightt">13.</td>
@@ -7563,16 +7521,16 @@ and eightfold have developed as two diverging branches.</p>
 </tr>
 
 <tr>
-<td class="center" rowspan="10">III.<br /><span class="oldtype">Jelly-polyps</span><br />Hydromedusæ<br />or<br /><span class="oldtype">Hood-jellies</span><br />Medusa</td>
+<td class="center" rowspan="10">III.<br /><span class="oldtype">Jelly-polyps</span><br />Hydromedusæ<br />or<br /><span class="oldtype">Hood-jellies</span><br />Medusa</td>
 <td class="center" rowspan="10"><div class="figcenter" style="width: 10px;"><img src="images/cb200.png" width="10" height="200" alt="{" /></div></td>
-<td class="center">VII. Archydræ<br /><i>Primæval Polyps</i></td>
+<td class="center">VII. Archydræ<br /><i>Primæval Polyps</i></td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30a.png" width="10" height="30" alt="{" /></div></td>
 <td class="rightm">17.</td>
 <td class="left vertm">Hydraria</td>
 <td class="left vertm bl  padl05">Hydra</td>
 </tr>
 <tr>
-<td class="center" rowspan="3">VIII. Leptomedusæ<br />Soft Jelly-fish</td>
+<td class="center" rowspan="3">VIII. Leptomedusæ<br />Soft Jelly-fish</td>
 <td class="center padb05" rowspan="3"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="rightt">18.</td>
 <td class="left">Vesiculata</td>
@@ -7590,7 +7548,7 @@ and eightfold have developed as two diverging branches.</p>
 </tr>
 
 <tr>
-<td class="center" rowspan="3">IX. Trachymedusæ<br /><i>Hard Jelly-fish</i></td>
+<td class="center" rowspan="3">IX. Trachymedusæ<br /><i>Hard Jelly-fish</i></td>
 <td class="center padb05" rowspan="3"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="rightt">21.</td>
 <td class="left">Marsiporchida</td>
@@ -7604,7 +7562,7 @@ and eightfold have developed as two diverging branches.</p>
 <tr>
 <td class="rightt">23.</td>
 <td class="left">Elasmorchida</td>
-<td class="left bl padb1 padl05">Charybdæ</td>
+<td class="left bl padb1 padl05">Charybdæ</td>
 </tr>
 
 <tr>
@@ -7615,15 +7573,15 @@ and eightfold have developed as two diverging branches.</p>
 <td class="left vertm bl padl05">Lucernaria</td>
 </tr>
 <tr>
-<td class="center" rowspan="2">XI. Discomedusæ<br /><i>Disc-jellies</i></td>
+<td class="center" rowspan="2">XI. Discomedusæ<br /><i>Disc-jellies</i></td>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb20.png" width="10" height="20" alt="{" /></div></td>
 <td class="rightt">25.</td>
-<td class="left">Semæostomeæ</td>
+<td class="left">Semæostomeæ</td>
 <td class="left bl padl05">Aurelia</td>
 </tr>
 <tr>
 <td class="rightt">26.</td>
-<td class="left">Rhizostomeæ</td>
+<td class="left">Rhizostomeæ</td>
 <td class="left bl padb1 padl05">Crambessa</td>
 </tr>
 
@@ -7651,7 +7609,7 @@ and eightfold have developed as two diverging branches.</p>
 </tr>
 <tr>
 <td class="rightt">30.</td>
-<td class="left">Tæniata</td>
+<td class="left">Tæniata</td>
 <td class="left bl padl05">Cestum</td>
 </tr>
 </table>
@@ -7668,15 +7626,15 @@ and eightfold have developed as two diverging branches.</p>
 <td colspan="2">&nbsp;</td>
 <td class="center" colspan="2">Ctenophora</td>
 <td colspan="3">&nbsp;</td>
-<td class="center">Hydromedusæ</td>
+<td class="center">Hydromedusæ</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td colspan="2">&nbsp;</td>
-<td class="center">Tæniata</td>
+<td class="center">Tæniata</td>
 <td class="center">Lobata</td>
 <td colspan="3">&nbsp;</td>
-<td class="center">Rhizostomeæ</td>
+<td class="center">Rhizostomeæ</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
@@ -7691,13 +7649,13 @@ and eightfold have developed as two diverging branches.</p>
 <td colspan="2">&nbsp;</td>
 <td class="center" colspan="2"><span class="figcenter" style="width: 75px;"><img src="images/cb75h.png" width="75" height="10" alt="-------------" /></span><br />Saccata<br />Stenostoma</td>
 <td colspan="3">&nbsp;</td>
-<td class="center">Semæostomeæ<br />Discomedusæ</td>
+<td class="center">Semæostomeæ<br />Discomedusæ</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td colspan="2">&nbsp;</td>
 <td class="center" colspan="2">&#9474;<br /></td>
-<td class="center">Trachymedusæ</td>
+<td class="center">Trachymedusæ</td>
 <td colspan="2">&nbsp;</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">Siphonophora</td>
@@ -7743,7 +7701,7 @@ and eightfold have developed as two diverging branches.</p>
 </tr>
 <tr>
 <td colspan="2">&nbsp;</td>
-<td class="center padl7" colspan="7"><span class="smcap">Leptomedusæ</span></td>
+<td class="center padl7" colspan="7"><span class="smcap">Leptomedusæ</span></td>
 </tr>
 <tr>
 <td colspan="4">&nbsp;</td>
@@ -7778,14 +7736,14 @@ and eightfold have developed as two diverging branches.</p>
 <td colspan="2">&nbsp;</td>
 </tr>
 <tr>
-<td class="center" colspan="5">Spongiæ</td>
+<td class="center" colspan="5">Spongiæ</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
 <td colspan="2">&nbsp;</td>
 </tr>
 <tr>
-<td class="center" colspan="3">Fibrospongiæ</td>
-<td class="center" colspan="2">Calcispongiæ</td>
+<td class="center" colspan="3">Fibrospongiæ</td>
+<td class="center" colspan="2">Calcispongiæ</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
 <td colspan="2">&nbsp;</td>
@@ -7869,7 +7827,7 @@ and eightfold have developed as two diverging branches.</p>
 <td class="center" colspan="3">&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center padr2" colspan="5"><span class="figcenter" style="width: 250px;"><img src="images/cb250h.png" width="250" height="10" alt="------------------------------------------------" /></span><br />Archispongiæ</td>
+<td class="center padr2" colspan="5"><span class="figcenter" style="width: 250px;"><img src="images/cb250h.png" width="250" height="10" alt="------------------------------------------------" /></span><br />Archispongiæ</td>
 <td class="center padr5" colspan="4"><span class="figcenter" style="width: 200px;"><img src="images/cb200h.png" width="200" height="10" alt="----------------------------------------" /></span><br />Hydroida</td>
 </tr>
 <tr>
@@ -7894,7 +7852,7 @@ and eightfold have developed as two diverging branches.</p>
 <td class="center padr3" colspan="9">&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center padr3" colspan="9">Gastræa</td>
+<td class="center padr3" colspan="9">Gastræa</td>
 </tr>
 </table>
 
@@ -8291,7 +8249,7 @@ phylogenesis.</p>
 
 <tr>
 <td colspan="4">&nbsp;</td>
-<td class="center">Chætopoda</td>
+<td class="center">Chætopoda</td>
 <td colspan="5">&nbsp;</td>
 </tr>
 <tr>
@@ -8400,7 +8358,7 @@ phylogenesis.</p>
 </tr>
 <tr>
 <td class="center">&nbsp;</td>
-<td class="center">Chætognatha</td>
+<td class="center">Chætognatha</td>
 <td class="center padl4">&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 <td class="center padl3" colspan="2"><div class="figcenter" style="width: 75px;"><img src="images/cb75h.png" width="75" height="10" alt="-------------" /></div></td>
@@ -8655,7 +8613,7 @@ phylogenesis.</p>
 </tr>
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center padl6" colspan="3"><b>Gastræa</b></td>
+<td class="center padl6" colspan="3"><b>Gastræa</b></td>
 <td class="center" colspan="4">&nbsp;</td>
 </tr>
 
@@ -9331,7 +9289,7 @@ to 26,800.</p>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
-<td class="center " colspan="5">Promollusca (Primæval Molluscs)<br />Molluscs with simple heart</td>
+<td class="center " colspan="5">Promollusca (Primæval Molluscs)<br />Molluscs with simple heart</td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
@@ -9347,7 +9305,7 @@ to 26,800.</p>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
-<td class="center " colspan="5">Gastræa</td>
+<td class="center " colspan="5">Gastræa</td>
 <td class="center">&nbsp;</td>
 </tr>
 
@@ -9611,7 +9569,7 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="rightt">12.</td>
 <td class="left">Bladder Lilies<br />with stalks</td>
 <td class="rightt">12.</td>
-<td class="left">Sphæronitida</td>
+<td class="left">Sphæronitida</td>
 </tr>
 <tr>
 <td class="blankrow05">&nbsp;</td>
@@ -9653,7 +9611,7 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="blankrow05">&nbsp;</td>
 </tr>
 <tr>
-<td class="center" rowspan="5"><br />IV.<br /><span class="oldtype">Sea Cucumbers</span><br /><b>Holothuriæ</b></td>
+<td class="center" rowspan="5"><br />IV.<br /><span class="oldtype">Sea Cucumbers</span><br /><b>Holothuriæ</b></td>
 <td class="center" rowspan="5"><div class="figcenter" style="width: 10px;"><img src="images/cb100.png" width="10" height="100" alt="{" /></div></td>
 <td class="center" rowspan="2">VIII.<br />Sea Cucumbers<br />with aquatic feet<br /><i>Eupodia</i></td>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb50.png" width="10" height="50" alt="{" /></div></td>
@@ -9698,19 +9656,19 @@ has developed into a common mouth for the whole cormus.</p>
 <tr>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="4">&nbsp;</td>
-<td class="center">Clypeastridæ</td>
+<td class="center">Clypeastridæ</td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center">Spatangidæ</td>
+<td class="center">Spatangidæ</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center">Dysasteridæ</td>
+<td class="center">Dysasteridæ</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&nbsp;</td>
@@ -9727,7 +9685,7 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="center">Synaptida</td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
-<td class="center" colspan="2">Cassidulidæ<br /><b>Petalosticha</b></td>
+<td class="center" colspan="2">Cassidulidæ<br /><b>Petalosticha</b></td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
@@ -9743,7 +9701,7 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="center">Liodermatida<br /><b>Apodia</b></td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center padr3" colspan="3"><div class="figcenter" style="width: 150px;"><img src="images/cb150h2.png" width="150" height="10" alt="------------------------" /></div></td>
-<td class="center">Echinonidæ</td>
+<td class="center">Echinonidæ</td>
 </tr>
 <tr>
 <td class="center">&nbsp;</td>
@@ -9756,7 +9714,7 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="center">&nbsp;</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
-<td class="center" colspan="3">Galeritidæ</td>
+<td class="center" colspan="3">Galeritidæ</td>
 <td class="center">&#9474;<br /></td>
 </tr>
 <tr>
@@ -9765,7 +9723,7 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="center">&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 <td class="center">&#9474;<br /></td>
-<td class="center">Echinometridæ</td>
+<td class="center">Echinometridæ</td>
 <td class="center">&#9474;<br /></td>
 </tr>
 <tr>
@@ -9785,9 +9743,9 @@ has developed into a common mouth for the whole cormus.</p>
 </tr>
 <tr>
 <td class="center">&nbsp;</td>
-<td class="center" colspan="2">Dendrochirota<br /><b>Eupodia</b><br /><b>Holothuriæ</b></td>
-<td class="center">Salenidæ</td>
-<td class="center" colspan="3">Latistellæ</td>
+<td class="center" colspan="2">Dendrochirota<br /><b>Eupodia</b><br /><b>Holothuriæ</b></td>
+<td class="center">Salenidæ</td>
+<td class="center" colspan="3">Latistellæ</td>
 </tr>
 <tr>
 <td class="center">&nbsp;</td>
@@ -9803,7 +9761,7 @@ has developed into a common mouth for the whole cormus.</p>
 <tr>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="2">&#9474;<br />&#9474;<br />&#9474;<br /></td>
-<td class="center">Angustistellæ<br /><b>Desmosticha</b><br /><b>Autechinida</b></td>
+<td class="center">Angustistellæ<br /><b>Desmosticha</b><br /><b>Autechinida</b></td>
 <td class="center" colspan="3">&nbsp;</td>
 </tr>
 <tr>
@@ -9811,21 +9769,21 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="center" colspan="2">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&nbsp;</td>
-<td class="center">Colocrinæ</td>
+<td class="center">Colocrinæ</td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
 <td class="center">Phytastra</td>
 <td class="center" colspan="2">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
-<td class="center">Sphæronitidæ</td>
+<td class="center">Sphæronitidæ</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
 <td class="center">&#9474;<br /></td>
 <td class="center" colspan="2">&#9474;<br /></td>
-<td class="center">Eocidaridæ</td>
+<td class="center">Eocidaridæ</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
 <td class="center">Eleutherocrina</td>
@@ -9842,7 +9800,7 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="center">Ophiastra<br /><b>Discogastra</b></td>
 <td class="center" colspan="2">&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
-<td class="center">Agelacrinæ<br /><b>Cystidea</b></td>
+<td class="center">Agelacrinæ<br /><b>Cystidea</b></td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 </tr>
@@ -9859,7 +9817,7 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="center" colspan="2">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">Melonitida<br />Palechinida<br /><b>Echinida</b></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
-<td class="center">Phatnocrinæ<br /><b>Brahiata</b></td>
+<td class="center">Phatnocrinæ<br /><b>Brahiata</b></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 </tr>
 <tr>
@@ -9917,7 +9875,7 @@ has developed into a common mouth for the whole cormus.</p>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
-<td class="center" colspan="6">Gastræa</td>
+<td class="center" colspan="6">Gastræa</td>
 <td class="center">&nbsp;</td>
 </tr>
 </table>
@@ -10228,14 +10186,14 @@ the present day.</p>
 <td colspan="7">&nbsp;</td>
 </tr>
 <tr>
-<td class="center padt05 padb05 bt br bb" colspan="2"><i>Legions of the</i><br /><i>Crustaceæ.</i></td>
-<td class="center padt05 padb05 bt br bb" colspan="2"><i>Orders of the</i><br /><i>Crustaceæ.</i></td>
+<td class="center padt05 padb05 bt br bb" colspan="2"><i>Legions of the</i><br /><i>Crustaceæ.</i></td>
+<td class="center padt05 padb05 bt br bb" colspan="2"><i>Orders of the</i><br /><i>Crustaceæ.</i></td>
 <td class="center padt05 padb05 bt br bb" colspan="2"><i>Systematic name</i><br /><i>of the Orders.</i></td>
 <td class="center padt05 padb05 bt bb"><i>Name of a</i><br /><i>Genus as an</i><br /><i>example.</i></td>
 </tr>
 <tr>
 <td class="center padt05 padb05 bb" colspan="7">I. <span class="smcap">Entomostraca</span>, <i>Lower Crustacea</i>, or Segmented Crabs (not passing through the
-actual Zoëa form in youth).</td>
+actual Zoëa form in youth).</td>
 </tr>
 <tr class="blankrow05">
 <td colspan="7">&nbsp;</td>
@@ -10244,7 +10202,7 @@ actual Zoëa form in youth).</td>
 <td class="center" rowspan="5"><b>I. Branchiopoda</b><br />Gill-footed Crabs</td>
 <td class="center" rowspan="5"><div class="figcenter" style="width: 10px;"><img src="images/cb75.png" width="10" height="75" alt="{" /></div></td>
 <td class="right">1.</td>
-<td class="left">Primæval Crabs</td>
+<td class="left">Primæval Crabs</td>
 <td class="right">1.</td>
 <td class="left">Archicarida</td>
 <td class="left">Nauplius</td>
@@ -10313,7 +10271,7 @@ actual Zoëa form in youth).</td>
 <td class="left">Fish Lice</td>
 <td class="right">9.</td>
 <td class="left">Siphonostoma</td>
-<td class="left">Lernæocera</td>
+<td class="left">Lernæocera</td>
 </tr>
 <tr>
 <td colspan="7">&nbsp;</td>
@@ -10350,7 +10308,7 @@ actual Zoëa form in youth).</td>
 <td colspan="7">&nbsp;</td>
 </tr>
 <tr>
-<td class="center padt05 padb05 bt bb" colspan="7">II. <span class="smcap">Malacostraca</span>, <i>Higher Crustacea</i>, or Mailed Crabs (passing through the Zoëa form
+<td class="center padt05 padb05 bt bb" colspan="7">II. <span class="smcap">Malacostraca</span>, <i>Higher Crustacea</i>, or Mailed Crabs (passing through the Zoëa form
 in youth).</td>
 </tr>
 <tr class="blankrow05">
@@ -10360,10 +10318,10 @@ in youth).</td>
 <td class="center" rowspan="4"><b>V. P&oelig;cilopoda</b><br />Oar-footed Crabs</td>
 <td class="center" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb50.png" width="10" height="50" alt="{" /></div></td>
 <td class="right">13.</td>
-<td class="left">Zoëa Crabs</td>
+<td class="left">Zoëa Crabs</td>
 <td class="right">13.</td>
-<td class="left">Zoëpoda</td>
-<td class="left">Zoëa</td>
+<td class="left">Zoëpoda</td>
+<td class="left">Zoëa</td>
 </tr>
 <tr>
 <td class="right">14.</td>
@@ -10409,7 +10367,7 @@ in youth).</td>
 <td class="right">19.</td>
 <td class="left">Wizard Crabs</td>
 <td class="right">19.</td>
-<td class="left">Læmodipoda</td>
+<td class="left">Læmodipoda</td>
 <td class="left">Caprella</td>
 </tr>
 <tr>
@@ -10441,7 +10399,7 @@ in youth).</td>
 <td class="center">&nbsp;</td>
 <td class="center">&#9474;<br /></td>
 <td class="center" colspan="4">&nbsp;</td>
-<td class="center">Læmodipoda</td>
+<td class="center">Læmodipoda</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 </tr>
@@ -10535,7 +10493,7 @@ in youth).</td>
 <tr>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center">Zoëpoda<br /><b>Malacostraca</b></td>
+<td class="center">Zoëpoda<br /><b>Malacostraca</b></td>
 <td class="center" colspan="4">&nbsp;</td>
 </tr>
 <tr>
@@ -10571,12 +10529,12 @@ in youth).</td>
 <tr>
 <td class="center">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
-<td class="center">Xiphosuræ</td>
+<td class="center">Xiphosuræ</td>
 <td class="center">&nbsp;</td>
-<td class="center">Zoëa</td>
+<td class="center">Zoëa</td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
-<td class="center">Cirripediæ<br /><b>Pectostraca</b></td>
+<td class="center">Cirripediæ<br /><b>Pectostraca</b></td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
@@ -10624,7 +10582,7 @@ in youth).</td>
 <tr>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="2">&#9474;<br /></td>
-<td class="center">Nebaliæ</td>
+<td class="center">Nebaliæ</td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&nbsp;</td>
@@ -10681,7 +10639,7 @@ in youth).</td>
 <td class="center">&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center">Cladoceræ</td>
+<td class="center">Cladoceræ</td>
 <td class="center" colspan="2">&#9474;<br /></td>
 <td class="center" >&#9474;<br /></td>
 <td class="center">&nbsp;</td>
@@ -10736,7 +10694,7 @@ in youth).</td>
 </tr>
 <tr>
 <td class="center">&nbsp;</td>
-<td class="center padl2" colspan="8"><b>Archicaridæ</b></td>
+<td class="center padl2" colspan="8"><b>Archicaridæ</b></td>
 </tr>
 <tr>
 <td class="center">&nbsp;</td>
@@ -10915,7 +10873,7 @@ Crustacea, the latter to Ringed worms.</p>
 <td class="center" rowspan="5">I.<br />Long spiders<br /><i>Arthrogastres</i></td>
 <td class="center" rowspan="5"><div class="figcenter" style="width: 10px;"><img src="images/cb150.png" width="10" height="150" alt="{" /></div></td>
 <td class="rightt">1.</td>
-<td class="left vertt">Scorpion spiders<br /><i>Solifugæ</i></td>
+<td class="left vertt">Scorpion spiders<br /><i>Solifugæ</i></td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="left">Solpuga<br />Galeodes</td>
 </tr>
@@ -10945,10 +10903,10 @@ Crustacea, the latter to Ringed worms.</p>
 </tr>
 
 <tr>
-<td class="center" rowspan="2">II.<br />Round spiders<br /><i>Sphærogastres</i></td>
+<td class="center" rowspan="2">II.<br />Round spiders<br /><i>Sphærogastres</i></td>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb50.png" width="10" height="50" alt="{" /></div></td>
 <td class="rightt">6.</td>
-<td class="left vertt">Spinning spiders<br /><i>Araneæ</i></td>
+<td class="left vertt">Spinning spiders<br /><i>Araneæ</i></td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="left">Epeira<br />Mygale</td>
 </tr>
@@ -11110,7 +11068,7 @@ Crustacea, the latter to Ringed worms.</p>
 </tr>
 <tr>
 <td class="center" colspan="4">&nbsp;</td>
-<td class="center">Primæval Flies<br /><i>Archiptera</i></td>
+<td class="center">Primæval Flies<br /><i>Archiptera</i></td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
@@ -11159,7 +11117,7 @@ Crustacea, the latter to Ringed worms.</p>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center">Weaving Spiders<br /><i>Araneæ</i><br />&#9474;<br />&#9474;<br /></td>
+<td class="center">Weaving Spiders<br /><i>Araneæ</i><br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="2">&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
@@ -11171,7 +11129,7 @@ Crustacea, the latter to Ringed worms.</p>
 <td class="center">&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center" colspan="4">Scorpion Spiders<br />Solifugæ<br /><span class="oldtype">Spiders.</span><br /><b>Arachnida</b></td>
+<td class="center" colspan="4">Scorpion Spiders<br />Solifugæ<br /><span class="oldtype">Spiders.</span><br /><b>Arachnida</b></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 </tr>
@@ -11455,7 +11413,7 @@ another in the history of the earth.</p>
 <td class="center" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb100.png" width="10" height="100" alt="{" /></div></td>
 
 <td class="rightt">1.</td>
-<td class="left">Primæval winged<br /><i>Archiptera</i></td>
+<td class="left">Primæval winged<br /><i>Archiptera</i></td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="left">M.I.<br />A.A.</td>
 <td class="center" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb100a.png" width="10" height="100" alt="{" /></div></td>
@@ -12091,7 +12049,7 @@ Vertebrata with head, with skull and brain, with centralized heart.</td>
 <td class="center" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt=
 "{" /></div></td>
 <td class="rightt">4.</td>
-<td class="left">Primæval fish</td>
+<td class="left">Primæval fish</td>
 <td class="rightt">4.</td>
 <td class="left">Selachii</td>
 </tr>
@@ -12127,7 +12085,7 @@ Vertebrata with head, with skull and brain, with centralized heart.</td>
 <td class="center" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb50.png" width="10" height="50" alt=
 "{" /></div></td>
 <td class="rightt">8.</td>
-<td class="left">Primæval<br />dragons</td>
+<td class="left">Primæval<br />dragons</td>
 <td class="rightt">8.</td>
 <td class="left">Simosauria</td>
 </tr>
@@ -12228,19 +12186,19 @@ Vertebrata with head, with skull and brain, with centralized heart.</td>
 <td class="rightt">21.</td>
 <td class="left">Long-tailed</td>
 <td class="rightt">21.</td>
-<td class="left">Saururæ</td>
+<td class="left">Saururæ</td>
 </tr>
 <tr>
 <td class="rightt">22.</td>
 <td class="left">Fan-tailed</td>
 <td class="rightt">22.</td>
-<td class="left">Carinatæ</td>
+<td class="left">Carinatæ</td>
 </tr>
 <tr>
 <td class="rightt">23.</td>
 <td class="left">Bush-tailed</td>
 <td class="rightt">23.</td>
-<td class="left">Ratitæ</td>
+<td class="left">Ratitæ</td>
 </tr>
 <tr class="blankrow">
 <td>&nbsp;</td>
@@ -12352,7 +12310,7 @@ Vertebrata with head, with skull and brain, with centralized heart.</td>
 <tr>
 
 <td class="center">&nbsp;</td>
-<td class="center">Primæval fish<br />3. Fishes<br /><span class="oldtype">Double-nostriled</span></td>
+<td class="center">Primæval fish<br />3. Fishes<br /><span class="oldtype">Double-nostriled</span></td>
 <td class="center padr4">Selachii<br /><i>Pisces</i><br /><b>Amphirrhina</b></td>
 <td class="center" colspan="2">&nbsp;</td>
 </tr>
@@ -12392,7 +12350,7 @@ Vertebrata with head, with skull and brain, with centralized heart.</td>
 </tr>
 <tr>
 <td class="center">Sea-barrels<br /><i>Thaliacea</i></td>
-<td class="center"><i>Ascidiæ</i><br />&#9474;<br /></td>
+<td class="center"><i>Ascidiæ</i><br />&#9474;<br /></td>
 <td class="center padl1" colspan="2"><div class="figcenter" style="width: 200px;"><img src="images/cb200h.png" width="200" height="10" alt=
 "-------------------------------" /></div></td>
 <td class="center">&nbsp;</td>
@@ -12513,7 +12471,7 @@ form of paddling fins.</p>
 <td>&nbsp;</td>
 </tr>
 <tr>
-<td class="center" rowspan="4"><span class="oldtype">A.<br />Primæval<br />Fish</span><br /><b>Selachii</b></td>
+<td class="center" rowspan="4"><span class="oldtype">A.<br />Primæval<br />Fish</span><br /><b>Selachii</b></td>
 <td class="center" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb75.png" width="10" height="75" alt=
 "{" /></div></td>
 <td class="center" rowspan="3">I. Transverse<br />mouths<br /><i>Plagiostomi</i></td>
@@ -12536,8 +12494,8 @@ form of paddling fins.</p>
 <td class="center vertt"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt=
 "{" /></div></td>
 <td class="center vertt">3.</td>
-<td class="left">Sea-Cats<br /><i>Chimæracei</i></td>
-<td class="left">Chimæra, Calorrhynchias</td>
+<td class="left">Sea-Cats<br /><i>Chimæracei</i></td>
+<td class="left">Chimæra, Calorrhynchias</td>
 </tr>
 <tr class="blankrow">
 <td>&nbsp;</td>
@@ -12551,7 +12509,7 @@ form of paddling fins.</p>
 "{" /></div></td>
 <td class="center vertt">4.</td>
 <td class="left">Buckler-heads<br /><i>Pamphracte</i></td>
-<td class="left">Cephalaspidæ, Placoderma, etc.</td>
+<td class="left">Cephalaspidæ, Placoderma, etc.</td>
 </tr>
 <tr>
 <td class="center vertt">5.</td>
@@ -12572,11 +12530,11 @@ form of paddling fins.</p>
 <tr>
 <td class="center vertt">7.</td>
 <td class="left"><i>Fulcrati</i></td>
-<td class="left">Palæoniscus, bony pike, etc.</td>
+<td class="left">Palæoniscus, bony pike, etc.</td>
 </tr>
 <tr>
 <td class="center vertt">8.</td>
-<td class="left"><i>Semæopteri</i></td>
+<td class="left"><i>Semæopteri</i></td>
 <td class="left">African finny pike, etc.</td>
 </tr>
 <tr class="blankrow">
@@ -12593,7 +12551,7 @@ form of paddling fins.</p>
 <tr>
 <td class="center vertt">10.</td>
 <td class="left"><i>Pycnoscolopes</i></td>
-<td class="left">Coccolepida, Amiadæ, etc.</td>
+<td class="left">Coccolepida, Amiadæ, etc.</td>
 </tr>
 <tr class="blankrow">
 <td>&nbsp;</td>
@@ -12737,7 +12695,7 @@ form of paddling fins.</p>
 <tr>
 <td class="center" colspan="2">Thrissogenes<br /><b>Physostomi</b><br /><b>Teleostei</b></td>
 <td class="center" colspan="2">&nbsp;</td>
-<td class="center"><br />Semæopteri<br /></td>
+<td class="center"><br />Semæopteri<br /></td>
 <td class="center" colspan="2">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="3">&nbsp;</td>
@@ -12829,7 +12787,7 @@ form of paddling fins.</p>
 <td class="center" colspan="2">&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center">Cephalaspidæ</td>
+<td class="center">Cephalaspidæ</td>
 <td class="center" colspan="3">&#9474;<br /></td>
 <td class="center">Rajacei</td>
 <td class="center">&#9474;<br /></td>
@@ -12855,7 +12813,7 @@ form of paddling fins.</p>
 <tr>
 <td class="center" colspan="4">&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
-<td class="center">Chimæracei<br /><b>Holocephali</b></td>
+<td class="center">Chimæracei<br /><b>Holocephali</b></td>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="4">&#9474;<br />&#9474;<br /></td>
 </tr>
@@ -13440,7 +13398,7 @@ lizards (Monitor, Varanus).</p>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt=
 "{" /></div></td>
 <td class="center vertt">1.</td>
-<td class="left">Primæval reptiles</td>
+<td class="left">Primæval reptiles</td>
 <td class="center vertt">1.</td>
 <td class="left">Proreptilia</td>
 <td class="center vertt">*</td>
@@ -13452,7 +13410,7 @@ lizards (Monitor, Varanus).</p>
 <td class="center vertt">2.</td>
 <td class="left">Thecodontia</td>
 <td class="center vertt">*</td>
-<td class="left vertt">Palæosaurus</td>
+<td class="left vertt">Palæosaurus</td>
 </tr>
 <tr class="blankrow">
 <td>&nbsp;</td>
@@ -13490,7 +13448,7 @@ lizards (Monitor, Varanus).</p>
 <td class="center vertt">6.</td>
 <td class="left">Glyptodermata</td>
 <td class="center vertt">&nbsp;</td>
-<td class="left vertt">Amphisbæna</td>
+<td class="left vertt">Amphisbæna</td>
 </tr>
 <tr>
 <td class="center vertt">7.</td>
@@ -13498,7 +13456,7 @@ lizards (Monitor, Varanus).</p>
 <td class="center vertt">7.</td>
 <td class="left">Vermilingues</td>
 <td class="center vertt">&nbsp;</td>
-<td class="left vertt">Chamæleo</td>
+<td class="left vertt">Chamæleo</td>
 </tr>
 <tr class="blankrow">
 <td>&nbsp;</td>
@@ -14282,7 +14240,7 @@ alt="{" /></div></td>
 <b>Marsupialia</b><br /><b>Zoophaga</b></td>
 <td class="center" rowspan="14"><div class="figcenter" style="width: 10px;"><img src="images/cb200.png" width="10" height="200"
 alt="{" /></div></td>
-<td class="center" colspan="2" rowspan="4">5. Insectivorous<br />Marsupial animals<br />Primæval pouched animals)</td>
+<td class="center" colspan="2" rowspan="4">5. Insectivorous<br />Marsupial animals<br />Primæval pouched animals)</td>
 <td class="rightm" rowspan="4">5.</td>
 <td class="left vertm" rowspan="4">Cantharophaga</td>
 <td class="center" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb50.png" width="10" height="50"
@@ -14541,7 +14499,7 @@ alt="{" /></div></td>
 <td class="center" rowspan="19">XI.<br /><span class="oldtype">Disc Placental</span><br /><span class="oldtype">Animals</span><br /><b>Zonoplacentalia</b></td>
 <td class="center vertt" rowspan="19"><div class="figcenter" style="width: 10px;"><img src="images/cb300.png" width="10" height="300"
 alt="{" /></div></td>
-<td class="center" rowspan="5">IX. Semi-apes<br /><i>Prosimiæ</i></td>
+<td class="center" rowspan="5">IX. Semi-apes<br /><i>Prosimiæ</i></td>
 <td class="center" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb50.png" width="10" height="50"
 alt="{" /></div></td>
 <td class="rightt">18.</td>
@@ -14637,7 +14595,7 @@ alt="{" /></div></td>
 <td>&nbsp;</td>
 </tr>
 <tr>
-<td class="center" rowspan="3">XIII. Apes<br /><i>Simiæ</i></td>
+<td class="center" rowspan="3">XIII. Apes<br /><i>Simiæ</i></td>
 <td class="center" rowspan="3"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30"
 alt="{" /></div></td>
 <td class="rightt">30.</td>
@@ -14649,13 +14607,13 @@ alt="{" /></div></td>
 <td class="rightt">31.</td>
 <td class="left">Flat-nosed</td>
 <td class="rightt">31.</td>
-<td class="left">Platyrrhinæ</td>
+<td class="left">Platyrrhinæ</td>
 </tr>
 <tr>
 <td class="rightt">32.</td>
 <td class="left">Narrow-nosed</td>
 <td class="rightt">32.</td>
-<td class="left">Catarrhinæ</td>
+<td class="left">Catarrhinæ</td>
 </tr>
 </table>
 
@@ -14686,7 +14644,7 @@ alt="{" /></div></td>
 <td class="center">Rock&nbsp;Conies<br /><i>Lamnungia</i></td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="2">&nbsp;</td>
-<td class="center">Narrow-nosed<br /><i>Catarrhinæ</i></td>
+<td class="center">Narrow-nosed<br /><i>Catarrhinæ</i></td>
 <td class="center">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
@@ -14706,7 +14664,7 @@ alt="{" /></div></td>
 <td class="center" colspan="2"><div class="figcenter" style="width: 100px;"><img src="images/cb100h.png" width="100" height="10"
 alt="{" /></div>Pseudo-hoofed<br /><i>Chelophora</i><br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
-<td class="center">Flat-nosed<br /><i>Platyrrhinæ</i><br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
+<td class="center">Flat-nosed<br /><i>Platyrrhinæ</i><br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 <td class="center">Flying foxes<br /><i>Pterocynes</i><br /><span class="oldtype">Flying&nbsp;Animals</span><br /><b>Chiroptera</b></td>
@@ -14727,7 +14685,7 @@ alt="{" /></div>Pseudo-hoofed<br /><i>Chelophora</i><br />&#9474;<br />&#9474;<b
 <td class="center " colspan="2"><span class="oldtype">Gnawing Animals</span><br />&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="2"><div class="figcenter" style="width: 100px;"><img src="images/cb100h.png" width="100" height="10"
-alt="{" /></div><span class="oldtype">Apes</span><br /><b>Simiæ</b><br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
+alt="{" /></div><span class="oldtype">Apes</span><br /><b>Simiæ</b><br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">Land animals of prey<br /><i>Carnivora</i><br /><span class="oldtype">Animals of Prey</span><br /><b>Carnaria</b></td>
@@ -15281,7 +15239,7 @@ alt="{" /></div></td>
 <td class="rightt">3.</td>
 <td class="left">Primary Odd-hoofs</td>
 <td class="rightt">3.</td>
-<td class="left">Palæotherida*</td>
+<td class="left">Palæotherida*</td>
 </tr>
 <tr>
 <td class="rightt">4.</td>
@@ -15312,7 +15270,7 @@ alt="{" /></div></td>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30"
 alt="{" /></div></td>
 <td class="rightt">8.</td>
-<td class="left">Primæval horses</td>
+<td class="left">Primæval horses</td>
 <td class="rightt">8.</td>
 <td class="left">Anchitherida*</td>
 </tr>
@@ -15339,7 +15297,7 @@ alt="{" /></div></td>
 </tr>
 <tr>
 <td class="rightt">11.</td>
-<td class="left">Primæval pigs</td>
+<td class="left">Primæval pigs</td>
 <td class="rightt">11.</td>
 <td class="left">Anthracotherida*</td>
 </tr>
@@ -15357,7 +15315,7 @@ alt="{" /></div></td>
 </tr>
 <tr>
 <td class="rightt">14.</td>
-<td class="left padr1">Primæval ruminants</td>
+<td class="left padr1">Primæval ruminants</td>
 <td class="rightt">14.</td>
 <td class="left">Xiphodontia*</td>
 </tr>
@@ -15372,7 +15330,7 @@ alt="{" /></div></td>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30"
 alt="{" /></div></td>
 <td class="rightt">15.</td>
-<td class="left">Primæval deer</td>
+<td class="left">Primæval deer</td>
 <td class="rightt">15.</td>
 <td class="left">Dremotherida*</td>
 </tr>
@@ -15402,7 +15360,7 @@ alt="{" /></div></td>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30"
 alt="{" /></div></td>
 <td class="rightt">19.</td>
-<td class="left">Primæval giraffes</td>
+<td class="left">Primæval giraffes</td>
 <td class="rightt">19.</td>
 <td class="left">Sivatherida*</td>
 </tr>
@@ -15420,7 +15378,7 @@ alt="{" /></div></td>
 <td class="center" rowspan="2"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30"
 alt="{" /></div></td>
 <td class="rightt">21.</td>
-<td class="left">Primæval gazelles</td>
+<td class="left">Primæval gazelles</td>
 <td class="rightt">21.</td>
 <td class="left">Antilocaprina*</td>
 </tr>
@@ -15546,7 +15504,7 @@ alt="{" /></div></td>
 <td class="center padl5" colspan="4">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center padl4" colspan="3">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
-<td class="center">Primæval horses<br /><i>Anchitherida</i></td>
+<td class="center">Primæval horses<br /><i>Anchitherida</i></td>
 </tr>
 <tr>
 <td class="center padl5" colspan="4">&#9474;<br /></td>
@@ -15614,7 +15572,7 @@ alt="{" /></div></td>
 <td class="center">&#9474;<br /></td>
 </tr>
 <tr>
-<td class="center" colspan="3">Primæval pigs<br /><i>Anthracotherida</i></td>
+<td class="center" colspan="3">Primæval pigs<br /><i>Anthracotherida</i></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">&nbsp;</td>
 <td class="center">Rhinoceros-horses<br /><i>Elasmotherida</i></td>
@@ -15638,7 +15596,7 @@ alt="{" /></div></td>
 </tr>
 <tr>
 <td class="center" colspan="3">&#9474;<br />&#9474;<br />&#9474;<br /></td>
-<td class="center">Primæval<br />ruminants<br /><i>Xiphodontia</i></td>
+<td class="center">Primæval<br />ruminants<br /><i>Xiphodontia</i></td>
 <td class="center padr1" colspan="2"><div class="figcenter" style="width: 100px;"><img src="images/cb100h.png" width="100" height="10" alt=
 "----------------" /></div>&#9474;<br />&#9474;<br /></td>
 <td class="center padl1" colspan="3">&#9474;<br />&#9474;<br />&#9474;<br /></td>
@@ -15653,7 +15611,7 @@ alt="{" /></div></td>
 <td class="center padl305" colspan="4"><div class="figcenter" style="width: 150px;"><img src="images/cb150h.png" width="150" height="10" alt=
 "------------------------" /></div><span class="oldtype">Primary Pair-hoofs</span><br /><b>Anoplotherida</b></td>
 <td class="center padr2" colspan="5"><div class="figcenter" style="width: 250px;"><img src="images/cb250h.png" width="250" height="10" alt=
-"----------------------------------------" /></div><span class="oldtype">Primary Odd-hoofs</span><br /><b>Palæotherida</b></td>
+"----------------------------------------" /></div><span class="oldtype">Primary Odd-hoofs</span><br /><b>Palæotherida</b></td>
 </tr>
 <tr>
 <td class="center padl305" colspan="4">&#9474;<br /></td>
@@ -16525,7 +16483,7 @@ of the Old World); (3) Platyrrhini (genuine American Apes);
 </tr>
 <tr>
 <td class="center padr3" colspan="5"><div class="figcenter" style="width: 350px;"><img src="images/cb350h.png" width="350" height="10" alt=
-"------------------------------------------------------" /></div><span class="oldtype">Apes</span><br /><b>Simiæ</b></td>
+"------------------------------------------------------" /></div><span class="oldtype">Apes</span><br /><b>Simiæ</b></td>
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
@@ -16533,7 +16491,7 @@ of the Old World); (3) Platyrrhini (genuine American Apes);
 <td class="center">&nbsp;</td>
 </tr>
 <tr>
-<td class="center padr2" colspan="5">Semi-apes<br /><i>Prosimiæ</i></td>
+<td class="center padr2" colspan="5">Semi-apes<br /><i>Prosimiæ</i></td>
 <td class="center">&nbsp;</td>
 </tr>
 </table>
@@ -17330,33 +17288,33 @@ Epoch</span></td>
 <td class="right">&nbsp;</td>
 <td class="left">&nbsp;</td>
 <td class="rightt">2.</td>
-<td class="left">Single-celled<br />Primæval animals</td>
+<td class="left">Single-celled<br />Primæval animals</td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
-<td class="left">Simple Am&oelig;bæ<br />(<i>Autom&oelig;bæ</i>)</td>
+<td class="left">Simple Am&oelig;bæ<br />(<i>Autom&oelig;bæ</i>)</td>
 </tr>
 <tr>
 <td class="right">&nbsp;</td>
 <td class="left">&nbsp;</td>
 <td class="rightt">3.</td>
-<td class="left">Many-celled<br />Primæval animals</td>
+<td class="left">Many-celled<br />Primæval animals</td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
-<td class="left">Communities of<br />Am&oelig;bæ<br />(<i>Synam&oelig;bæ</i>)</td>
+<td class="left">Communities of<br />Am&oelig;bæ<br />(<i>Synam&oelig;bæ</i>)</td>
 </tr>
 <tr>
 <td class="right">&nbsp;</td>
 <td class="left">&nbsp;</td>
 <td class="rightt">4.</td>
-<td class="left">Ciliated planulæ<br />(<i>Planæada</i>)</td>
+<td class="left">Ciliated planulæ<br />(<i>Planæada</i>)</td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
-<td class="left">Planula larvæ</td>
+<td class="left">Planula larvæ</td>
 </tr>
 <tr>
 <td class="rightt">1.</td>
 <td class="left">Laurentian Period</td>
 <td class="rightt">5.</td>
-<td class="left">Primæval Intestinal<br />animals<br />(<i>Gastræada</i>)</td>
+<td class="left">Primæval Intestinal<br />animals<br />(<i>Gastræada</i>)</td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
-<td class="leftm">Gastrula larvæ</td>
+<td class="leftm">Gastrula larvæ</td>
 </tr>
 <tr>
 <td class="rightt">2.</td>
@@ -17380,7 +17338,7 @@ Epoch</span></td>
 <td class="rightt">8.</td>
 <td class="left">Sack worms<br />(<i>Himatega</i>)</td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
-<td class="left">Sea-squirts<br />(<i>Ascidiæ</i>)</td>
+<td class="left">Sea-squirts<br />(<i>Ascidiæ</i>)</td>
 </tr>
 <tr>
 
@@ -17407,13 +17365,13 @@ Epoch</span></td>
 <tr>
 <td class="left bb" colspan="2">(Compare p. <a href="#Page_22">22</a>, and<br />Plate <a href="#plxiv">XIV</a>. and its explanation.)</td>
 <td class="rightt bb">11.</td>
-<td class="left bb">Primæval fish<br />(<i>Selachii</i>)</td>
+<td class="left bb">Primæval fish<br />(<i>Selachii</i>)</td>
 <td class="center bb"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="left bb">Sharks<br />(<i>Squalacei</i>)</td>
 </tr>
 <tr>
 <td class="center bb" rowspan="3"><span class="smcap">II.<br />
-Palæolithic<br />
+Palæolithic<br />
 or<br />
 Primary<br />
 Epoch</span></td>
@@ -17453,7 +17411,7 @@ Epoch</span></td>
 <td class="left">Trias Period</td>
 <td class="center  bb" rowspan="3"><div class="figcenter" style="width: 10px;"><img src="images/cb100.png" width="10" height="100" alt="{" /></div></td>
 <td class="rightt">15.</td>
-<td class="left">Primæval Amniota<br />(<i>Protamnia</i>)</td>
+<td class="left">Primæval Amniota<br />(<i>Protamnia</i>)</td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="left">?Between the Tailed-Amphibia<br />and Primary mammals</td>
 </tr>
@@ -17484,7 +17442,7 @@ Epoch</span></td>
 <td class="left">&nbsp;</td>
 <td class="center  bb" rowspan="4"><div class="figcenter" style="width: 10px;"><img src="images/cb100.png" width="10" height="100" alt="{" /></div></td>
 <td class="rightt">18.</td>
-<td class="left">Semi-apes<br />(<i>Prosimiæ</i>)</td>
+<td class="left">Semi-apes<br />(<i>Prosimiæ</i>)</td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
 <td class="left">Lori (<i>Stenops</i>)<br />Maki (<i>Lemur</i>)</td>
 </tr>
@@ -18547,7 +18505,7 @@ alt="{" /></div><span class="oldtype">Woolly-haired</span><br /><b>Ulotrichi</b>
 <tr>
 <td class="center">&nbsp;</td>
 <td class="center" colspan="9"><div class="figcenter" style="width: 400px;"><img src="images/cb400h.png" width="400" height="10"
-alt="{" /></div><b>Primæval Men</b></td>
+alt="{" /></div><b>Primæval Men</b></td>
 </tr>
 </table>
 
@@ -19299,7 +19257,7 @@ kindred Magyars, and in Turkey by the Osmanlis.</p>
 <td class="center" colspan="3">Himiarites</td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="2"><div class="figcenter" style="width: 100px;"><img src="images/cb100h.png" width="100" height="10" alt=
-"-------------------" /></div><b>Aramæans</b></td>
+"-------------------" /></div><b>Aramæans</b></td>
 <td class="center" colspan="2">&#9474;<br />&#9474;<br /></td>
 </tr>
 <tr>
@@ -19314,7 +19272,7 @@ kindred Magyars, and in Turkey by the Osmanlis.</p>
 "-------------------" /></div><b>South Arabians</b></td>
 <td class="center"><b>North Arabians</b></td>
 <td class="center" colspan="4"><div class="figcenter" style="width: 200px;"><img src="images/cb200h.png" width="200" height="10" alt=
-"-------------------" /></div><b>Primæval Jews</b><br /><b>North-Semites</b></td>
+"-------------------" /></div><b>Primæval Jews</b><br /><b>North-Semites</b></td>
 </tr>
 <tr>
 <td class="center" colspan="4">&#9474;<br /></td>
@@ -19339,7 +19297,7 @@ kindred Magyars, and in Turkey by the Osmanlis.</p>
 <td class="center">&nbsp;</td>
 <td class="center"><br />Guanchites</td>
 <td class="center" colspan="3">&nbsp;</td>
-<td class="center padl5" colspan="4">Eusemites (<b>Primæval Semites</b>)<br />(Semites in a narrow sense)</td>
+<td class="center padl5" colspan="4">Eusemites (<b>Primæval Semites</b>)<br />(Semites in a narrow sense)</td>
 
 </tr>
 <tr>
@@ -19419,7 +19377,7 @@ kindred Magyars, and in Turkey by the Osmanlis.</p>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center">Modern<br />Egyptians<br />(<b>Copts</b>)</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
-<td class="center">Primæval<br />Ph&oelig;nicians</td>
+<td class="center">Primæval<br />Ph&oelig;nicians</td>
 <td class="center">Babylonians</td>
 <td class="center">Assyrians</td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
@@ -19664,7 +19622,7 @@ alt="{" /></div></td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
 <td class="center">&#9474;<br /></td>
-<td class="center padr12" colspan="5"><b>Primæval Germans</b></td>
+<td class="center padr12" colspan="5"><b>Primæval Germans</b></td>
 <td class="center">&#9474;<br /></td>
 </tr>
 <tr>
@@ -19777,7 +19735,7 @@ alt="{" /></div><b>Sclavo-Germans&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</b><
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="2">&nbsp;</td>
 <td class="center" colspan="2"><div class="figcenter" style="width: 75px;"><img src="images/cb75h.png" width="75" height="10"
-alt="{" /></div><b>Primæval Thracians</b></td>
+alt="{" /></div><b>Primæval Thracians</b></td>
 <td class="center">&#9474;<br />&#9474;<br />&#9474;<br /></td>
 <td class="center" colspan="3">&nbsp;</td>
 
@@ -19798,7 +19756,7 @@ alt="{" /></div><b>Primæval Thracians</b></td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center">&#9474;<br />&#9474;<br /></td>
 <td class="center padl1" colspan="3"><div class="figcenter" style="width: 125px;"><img src="images/cb125h.png" width="125" height="10"
-alt="{" /></div><b>Græco-Romans</b></td>
+alt="{" /></div><b>Græco-Romans</b></td>
 <td class="center" colspan="3">&nbsp;</td>
 </tr>
 <tr>
@@ -19952,7 +19910,7 @@ a Compound Prim&aelig;val Language.</p></td>
 <td class="center bl">Pr</td>
 <td class="center bl">Mn</td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
-<td class="left">South Africa (between 30°&nbsp;Lat.&nbsp;and 5°&nbsp;N.&nbsp;Lat.)</td>
+<td class="left">South Africa (between 30°&nbsp;Lat.&nbsp;and 5°&nbsp;N.&nbsp;Lat.)</td>
 </tr>
 <tr>
 <td class="center">4.</td>
@@ -19961,7 +19919,7 @@ a Compound Prim&aelig;val Language.</p></td>
 <td class="center bl">Pr</td>
 <td class="center bl">Pl</td>
 <td class="center"><div class="figcenter" style="width: 10px;"><img src="images/cb30.png" width="10" height="30" alt="{" /></div></td>
-<td class="left">Central Africa (between the Equator and 30°&nbsp;N.&nbsp;Lat.)</td>
+<td class="left">Central Africa (between the Equator and 30°&nbsp;N.&nbsp;Lat.)</td>
 </tr>
 <tr>
 <td class="center" colspan="4">&nbsp;</td>
@@ -24105,383 +24063,6 @@ enterprises and heroic achievements.&#8221;&mdash;<i>New York Evening Post.</i><
 
 <p><i>D. APPLETON &amp; CO., Publishers, 1, 3, &amp; 5 Bond Street, N. Y.</i></p>
 
-
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-
-<pre>
-
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-
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+<div>*** END OF THE PROJECT GUTENBERG EBOOK 40473 ***</div>
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-Project Gutenberg's The History of Creation, Vol. II (of 2), by Ernst Haeckel
-
-This eBook is for the use of anyone anywhere at no cost and with
-almost no restrictions whatsoever.  You may copy it, give it away or
-re-use it under the terms of the Project Gutenberg License included
-with this eBook or online at www.gutenberg.org
-
-
-Title: The History of Creation, Vol. II (of 2)
-       Or the Development of the Earth and its Inhabitants by the
-       Action of Natural Causes
-
-Author: Ernst Haeckel
-
-Translator: E. Ray Lankester
-
-Release Date: August 14, 2012 [EBook #40473]
-
-Language: English
-
-Character set encoding: ASCII
-
-*** START OF THIS PROJECT GUTENBERG EBOOK HISTORY OF CREATION, VOL II ***
-
-
-
-
-Produced by Adrian Mastronardi, Turgut Dincer, Jason Palmer
-and the Online Distributed Proofreading Team at
-http://www.pgdp.net (This file was produced from images
-generously made available by The Internet Archive)
-
-
-
-
-
-
-
-
-
-  +------------------------------------------------------------------+
-  | Transcriber's note:                                              |
-  |                                                                  |
-  | This book was published in two volumes, of which this is the     |
-  | second. The first volume was released as Project Gutenberg ebook |
-  | #40472, available at http://www.gutenberg.org/ebooks/40472       |
-  |                                                                  |
-  | Numbers enclosed in square brackets, e.g. [1], relate to         |
-  | footnotes, which have been placed at the end of the text.        |
-  | Numbers enclosed in parentheses, e.g. (1), relate to works       |
-  | referred to in the text and listed at the end of this volume.    |
-  |                                                                  |
-  | In the text versions of these two volumes, words in _italics_    |
-  | are enclosed in underscores, +bold+ words are enclosed in plus   |
-  | signs, and words in =Gothic script= are enclosed in equal signs. |
-  | Curly brackets are used to represent subscripts, e.g. k{1}.      |
-  +------------------------------------------------------------------+
-
-
-
-
-  THE HISTORY OF CREATION.
-
-
-
-
-[Illustration: Hypothetical Sketch of the Monophyletic Origin of Man.]
-
-
-
-
-  THE
-  HISTORY OF CREATION:
-
-  _OR THE DEVELOPMENT OF THE EARTH AND ITS
-  INHABITANTS BY THE ACTION OF NATURAL CAUSES._
-
-  A POPULAR EXPOSITION OF
-  THE DOCTRINE OF EVOLUTION IN GENERAL, AND OF THAT OF
-  DARWIN, GOETHE, AND LAMARCK IN PARTICULAR.
-
-  FROM THE GERMAN OF
-  ERNST HAECKEL,
-  PROFESSOR IN THE UNIVERSITY OF JENA.
-
-  THE TRANSLATION REVISED BY
-  PROFESSOR E. RAY LANKESTER, M.A., F.R.S.,
-  FELLOW OF EXETER COLLEGE, OXFORD.
-
-  _IN TWO VOLUMES._
-  VOL. II.
-
-  NEW YORK:
-  D. APPLETON AND COMPANY,
-  1, 3, AND 5 BOND STREET.
-  1880.
-
-
-
-
-                        A sense sublime
-  Of something far more deeply interfused,
-  Whose dwelling is the light of setting suns,
-  And the round ocean, and the living air,
-  And the blue sky, and in the mind of man;
-  A motion and a spirit that impels
-  All thinking things, all objects of all thought,
-  And rolls through all things.
-
-  In all things, in all natures, in the stars
-  Of azure heaven, the unenduring clouds,
-  In flower and tree, in every pebbly stone
-  That paves the brooks, the stationary rocks,
-  The moving waters and the invisible air.
-
-                                   WORDSWORTH.
-
-
-
-
-CONTENTS OF VOL. II.
-
-
-  CHAPTER XV.
-                                                                    PAGE
-  PERIODS OF CREATION AND RECORDS OF CREATION.
-
-  Reform of Systems by the Theory of Descent.--The Natural System
-  as a Pedigree.--Palaeontological Records of the
-  Pedigree.--Petrifactions as Records of Creation.--Deposits of the
-  Neptunic Strata and the Enclosure of Organic Remains.--Division
-  of the Organic History of the Earth into Five Main Periods:
-  Period of the Tangle Forests, Fern Forests, Pine Forests,
-  Foliaceous Forests, and of Cultivation.--The Series of Neptunic
-  Strata.--Immeasurable Duration of the Periods which have elapsed
-  during their Formation.--Deposits of Strata only during the
-  Sinking, not during the Elevation of the Ground.--Other Gaps in
-  the Records of Creation.--Metamorphic Condition of the most
-  Ancient Neptunic Strata.--Small Extent of Palaeontological
-  Experience.--Small proportion of Organisms and of Parts of
-  Organisms Capable of Petrifying.--Rarity of many Petrified
-  Species.--Want of Fossilised Intermediate Forms.--Records of the
-  Creation in Ontogeny and in Comparative Anatomy                      1
-
-
-  CHAPTER XVI.
-
-  PEDIGREE AND HISTORY OF THE KINGDOM OF THE PROTISTA.
-
-  Special Mode of Carrying out the Theory of Descent in the
-  Natural System of Organisms.--Construction of Pedigrees.--Descent
-  of all Many-celled from Single-celled Organisms.--Descent of
-  Cells from Monera.--Meaning of Organic Tribes, or Phyla.--Number
-  of the Tribes in the Animal and Vegetable Kingdoms.--The
-  Monophyletic Hypothesis of Descent, or the Hypothesis of one
-  Common Progenitor, and the Polyphyletic Hypothesis of Descent,
-  or the Hypothesis of many Progenitors.--The Kingdom of Protista,
-  or Primaeval Beings.--Eight Classes of the Protista Kingdom:
-  Monera, Amoebae, or Protoplastae; Whip-swimmers, or Flagellata;
-  Ciliated-balls, Cili Catallacta; Labyrinth-streamers, or
-  Labyrinthuleae; Flint-cells, or Diatomeae; Mucous-moulds, or
-  Myxomycetes; Root-footers (Rhizopoda).--Remarks on the General
-  Natural History of the Protista: Their Vital Phenomena,
-  Chemical Composition, and Formation (Individuality and
-  Fundamental Form).--Phylogeny of the Prostista Kingdom              36
-
-
-  CHAPTER XVII.
-
-  PEDIGREE AND HISTORY OF THE VEGETABLE KINGDOM.
-
-  The Natural System of the Vegetable Kingdom.--Division of the
-  Vegetable Kingdom into Six Branches and Eighteen Classes.--The
-  Flowerless Plants (Cryptogamia).--Sub-kingdom of the Thallus
-  Plants.--The Tangles, or Algae (Primary Algae, Green Algae, Brown
-  Algae, Red Algae).--The Thread-plants, or Inophytes (Lichens and
-  Fungi).--Sub-kingdom of the Prothallus Plants.--The Mosses, or
-  Muscinae (Water-mosses, Liverworts, Leaf-mosses,
-  Bog-mosses).--The Ferns, or Filicinae (Leaf-ferns, Bamboo-ferns,
-  Water-ferns, Scale-ferns).--Sub kingdom of Flowering Plants
-  (Phanerogamia).--The Gymnosperms, or Plants with Naked Seeds
-  (Palm-ferns = Cycadeae; Pines = Coniferae).--The Angiosperms, or
-  Plants with Enclosed Seeds.--Monocotylae.--Dicotylae.--Cup-blossoms
-  (Apetalae).--Star-blossoms (Diapetalae).--Bell-blossoms
-  (Gamopetalae)                                                        77
-
-
-  CHAPTER XVIII.
-
-  PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-  I. ANIMAL-PLANTS AND WORMS.
-
-  The Natural System of the Animal Kingdom.--Linnaeus' and Lamarck's
-  Systems.--The Four Types of Baer and Cuvier.--Their Increase to
-  Seven Types.--Genealogical Importance of the Seven Types as
-  Independent Tribes of the Animal Kingdom.--Derivation of
-  Zoophytes and Worms from Primaeval Animals.--Monophyletic and
-  Polyphyletic Hypothesis of the Descent of the Animal
-  Kingdom.--Common Origin of the Four Higher Animal Tribes out of
-  the Worm Tribe.--Division of the Seven Animal Tribes into
-  Sixteen Main Classes, and Thirty-eight Classes.--Primaeval
-  Animals (Monera, Amoebae, Synamoebae), Gregarines, Infusoria,
-  Planaeades, and Gastraeades (Planula and Gastrula).--Tribe of
-  Zoophytes.--Spongiae (Mucous Sponges, Fibrous Sponges, Calcareous
-  Sponges).--Sea Nettles, or Acalephae (Corals, Hood-jellies,
-  Comb-jellies).--Tribe of Worms                                     117
-
-
-  CHAPTER XIX.
-
-  PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-  II. MOLLUSCA, STAR-FISHES, AND ARTICULATED ANIMALS.
-
-  Tribe of Molluscs.--Four Classes of Molluscs: Lamp-shells
-  (Spirobranchia); Mussels (Lamellibranchia); Snails (Cochlides);
-  Cuttle-fish (Cephalopoda).--Tribe of Star-fishes, or
-  Echinoderma.--Their Derivation from Ringed Worms (Mailed Worms,
-  or Phracthelminthes).--The Alternation of Generation in the
-  Echinoderma.--Four Classes of Star-fish: Sea-stars (Asteridea);
-  Sea-lilies (Crinoidea); Sea-urchins (Echinidea); Sea-cucumbers
-  (Holothuridea).--Tribe of Articulated Animals, or
-  Arthropoda.--Four Classes of Articulated Animals: Branchiata, or
-  Crustacea, breathing through gills; Jointed Crabs; Mailed
-  Crabs; Articulata Tracheata, breathing through Air
-  Tubes.--Spiders (Long Spiders, Round
-  Spiders).--Myriopods.--Insects.--Chewing and Sucking
-  Insects.--Pedigree and History of the Eight Orders of Insects      154
-
-
-  CHAPTER XX.
-
-  PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-  III. VERTEBRATE ANIMALS.
-
-  The Records of the Creation of Vertebrate Animals (Comparative
-  Anatomy, Embryology, and Palaeontology).--The Natural System of
-  Vertebrate Animals.--The Four Classes of Vertebrate Animals,
-  according to Linnaeus and Lamarck.--Their Increase to Nine
-  Classes.--Main Class of the Tube-hearted, or Skull-less Animals
-  (the Lancelet).--Blood Relationship between the Skull-less Fish
-  and the Tunicates.--Agreement in the Embryological Development
-  of Amphioxus and Ascidiae.--Origin of the Vertebrate Tribe out of
-  the Worm Tribe.--Main Class of Single-nostriled, or
-  Round-mouthed Animals (Hag and Lampreys).--Main Class of
-  Anamnionate Animals, devoid of Amnion.--Fishes (Primaeval Fish,
-  Cartilaginous Fish, Osseous Fish).--Mud-fish, or Dipneusta.--Sea
-  Dragons, or Halisauria.--Frogs and Salamanders, or Amphibia
-  (Mailed Amphibia, Naked Amphibia).--Main Class of Amnionate
-  Animals, or Amniota.--Reptiles (Primary Reptiles, Lizards,
-  Serpents, Crocodiles, Tortoises, Flying Reptiles, Dragons,
-  Beaked Reptiles).--Birds (Feather-tailed, Fan-tailed,
-  Bush-tailed)                                                       192
-
-
-  CHAPTER XXI.
-
-  PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-  IV. MAMMALS.
-
-  The System of Mammals according to Linnaeus and
-  Blainville.--Three Sub-classes of Mammals (Ornithodelphia,
-  Didelphia, Monodelphia).--Ornithodelphia, or Monotrema.--Beaked
-  Animals (Ornithostoma).--Didelphia, or Marsupials.--Herbivorous
-  and Carnivorous Marsupials.--Monodelphia, or Placentalia
-  (Placental Animals).--Meaning of the Placenta.--Tuft
-  Placentalia.--Girdle Placentalia.--Disc
-  Placentalia.--Non-deciduates, or Indeciduata.--Hoofed
-  Animals.--Single and Double-hoofed Animals.--Whales.--Toothless
-  Animals.--Deciduates, or Animals with
-  Decidua.--Semi-apes.--Gnawing Animals.--Pseudo-hoofed
-  Animals.--Insectivora.--Beasts of Prey.--Bats.--Apes               231
-
-
-  CHAPTER XXII.
-
-  ORIGIN AND PEDIGREE OF MAN.
-
-  The Application of the Theory of Descent to Man.--Its Immense
-  Importance and Logical Necessity.--Man's Position in the Natural
-  System of Animals, among Disco-placental Animals.--Incorrect
-  Separation of the Bimana and Quadrumana.--Correct Separation of
-  Semi-apes from Apes.--Man's Position in the Order of
-  Apes.--Narrow-nosed Apes (of the Old World) and Flat-nosed Apes
-  (of America).--Difference of the two Groups.--Origin of Man from
-  Narrow-nosed Apes.--Human Apes, or Anthropoides.--African
-  Human-apes (Gorilla and Chimpanzee).--Asiatic Human-apes (Orang
-  and Gibbon).--Comparison between the different Human Apes and
-  the different Races of Men.--Survey of the Series of the
-  Progenitors of Man.--Invertebrate Progenitors (Prochordata) and
-  Vertebrate Progenitors                                             263
-
-
-  CHAPTER XXIII.
-
-  MIGRATION AND DISTRIBUTION OF MANKIND. HUMAN SPECIES AND HUMAN
-  RACES.
-
-  Age of the Human Race.--Causes of its Origin.--The Origin of
-  Human Language.--Monophyletic or Single, Polyphyletic or
-  Multiple Origin of the Human Race.--Derivation of Man from many
-  Pairs.--Classification of the Human Races.--System of Twelve
-  Species of Men.--Woolly-Haired Men, or Ulotrichis.--Bushy-Haired
-  (Papuans, Hottentots).--Fleecy-haired (Caffres,
-  Negroes).--Straight-haired Men, or Lissotrichi.--Stiff-haired
-  (Australians, Malays, Mongols, Arctic, and American
-  Tribes).--Curly-haired (Dravidas, Nubians, Midlanders).--Number
-  of Population.--Primaeval Home of Man (South Asia, or
-  Lemuria).--Nature of Primaeval Men.--Number of Primaeval Languages
-  (Monoglottists and Polyglottists).--Divergence and Migration of
-  the Human Race.--Geographical Distribution of the Human Species    296
-
-
-  CHAPTER XXIV.
-
-  OBJECTIONS AGAINST, AND PROOFS OF THE TRUTH OF, THE THEORY OF
-  DESCENT.
-
-  Objections to the Doctrine of Filiation.--Objections of Faith
-  and Reason.--Immeasurable Length of the Geological
-  Periods.--Transition Forms between Kindred Species.--Dependence
-  of Stability of Form on Inheritance, and of the Variability of
-  Form on Adaptation.--Origin of very Complicated Arrangement of
-  Organisation.--Gradual Development of Instincts and Mental
-  Activities.--Origin of a priori Knowledge from Knowledge a
-  posteriori.--The Knowledge requisite for the Correct
-  Understanding of the Doctrine of Filiation.--Necessary
-  Interaction between Empiricism and Philosophy.--Proofs of the
-  Theory of Descent.--Inner Causal-Connection between all the
-  Biological Series of Phenomena.--The Direct Proof of the Theory
-  of Selection.--Relation of the Theory of Descent to
-  Anthropology.--Proofs of the Animal Origin of Man.--The Pithecoid
-  Theory as an Inseparable Part of the Theory of
-  Descent.--Induction and Deduction.--Gradual Development of the
-  Human Mind.--Body and Mind.--Human Soul and Animal Soul.--A Glance
-  at the Future                                                      334
-
-
-  LIST OF WORKS REFERRED TO IN THE TEXT                              371
-
-  APPENDIX (Explanation of the Plates)                               379
-
-  INDEX                                                              402
-
-
-
-
-LIST OF ILLUSTRATIONS.
-
-
-PLATES.
-
-    XV.--Hypothetical Sketch of the Monophyletic Origin
-          of Man                                          _Frontispiece_
-
-    IV.--Hand of Nine different Mammals                _To face page_ 34
-
-     V.--Single-Stemmed, or Monophyletic, Pedigree of the
-          Vegetable Kingdom                                    "     112
-
-    VI.--Historical Growth of the Six Great Stems of Animals   "     122
-
-   VII.--Animal Plants, or Zoophytes                           "     140
-
-  VIII.--Star Fishes--First Generation            _Between pp._ 170, 171
-
-    IX.--Star Fishes--Second Generation                 "        "    "
-
-     X.--Nauplius-Youth-Form of Six Crab Fish           "       174, 175
-
-    XI.--Adult-Form of the same Six Crab Fish           "        "    "
-
-   XII.--Ascidia and Amphioxus                          "       201, 202
-
-  XIII.--Ascidia and Amphioxus                          "        "    "
-
-   XIV.--Single, or Monophyletic, Pedigree of Back-boned
-         Animals                                      _To face page_ 222
-
-
-  FIGURES.
-
-   8.--Protamoeba Primitiva                                           52
-
-   9.--Bathybius Haeckelii                                             53
-
-  10.--Amoeba Sphaerococcus                                            54
-
-  11.--Euglena Striata                                                57
-
-  12.--Magosphaera Planula                                             58
-
-  13.--Labyrinthula Macrocystis                                       59
-
-  14.--Navicula Hippocampus                                           60
-
-  15.--Physarum Albipes                                               61
-
-  16.--Cyrtidosphaera Echinoides                                       66
-
-  17.--Caulerpa Denticulata                                           87
-
-  18.--Euastrum Rota                                                  88
-
-  19.--Fucus Vesiculosus (egg of)                                     90
-
-
-
-
-THE HISTORY OF CREATION.
-
-
-
-
-CHAPTER XV.
-
-PERIODS OF CREATION AND RECORDS OF CREATION.
-
-
-  Reform of Systems by the Theory of Descent.--The Natural System
-  as a Pedigree.--Palaeontological Records of the
-  Pedigree.--Petrifactions as Records of Creation.--Deposits of the
-  Neptunic Strata and the Enclosure of Organic Remains.--Division
-  of the Organic History of the Earth into Five Main Periods:
-  Period of the Tangle Forests, Fern Forests, Pine Forests,
-  Foliaceous Forests, and of Cultivation.--The Series of Neptunic
-  Strata.--Immeasurable Duration of the Periods which have elapsed
-  during their Formation.--Deposits of Strata only during the
-  Sinking, not during the Elevation of the Ground.--Other Gaps in
-  the Records of Creation.--Metamorphic Condition of the most
-  Ancient Neptunic Strata.--Small Extent of Palaeontological
-  Experience.--Small proportion of Organisms and of Parts of
-  Organisms Capable of Petrifying.--Rarity of many Petrified
-  Species.--Want of Fossilised Intermediate Forms.--Records of the
-  Creation in Ontogeny and in Comparative Anatomy.
-
-
-The revolutionary influence which the Theory of Descent must exercise
-upon all sciences, will in all probability affect no branch of science,
-excepting Anthropology, so much as the descriptive portion of natural
-history, that which is known as systematic Zoology and Botany. Most
-naturalists who have hitherto occupied themselves with arranging the
-different systems of animals and plants, have collected, named, and
-arranged the different species of these natural bodies with much the
-same interest as antiquarians and ethnographers collect the weapons and
-utensils of different nations. Many have not even risen above the degree
-of intelligence with which people usually collect, label, and arrange
-crests, stamps, and similar curiosities. In the same manner as some
-collectors find their pleasure in the similarity of forms, the beauty or
-rarity of the crests or stamps, and admire in them the inventive art of
-man, so many naturalists take a delight in the manifold forms of animals
-and plants, and marvel at the rich imagination of the Creator, at His
-unwearied creative activity, and at His curious fancy for forming, by
-the side of so many beautiful and useful organisms, also a number of
-ugly and useless ones.
-
-This childlike treatment of systematic Zoology and Botany is completely
-annihilated by the Theory of Descent. In the place of the superficial
-and playful interest with which most naturalists have hitherto regarded
-organic structures, we now have the much higher interest of the
-intelligent understanding which detects in the _related forms_ of
-organisms their true _blood relationships_. The _Natural System of
-animals and plants_, which was formerly valued either only as a registry
-of names, to facilitate the survey of the different forms, or as a table
-of contents for the short expression of their degrees of similarity,
-receives from the Theory of Descent the incomparably higher value of a
-true _pedigree of organisms_. This pedigree is to disclose to us the
-genealogical connection of the smaller and larger groups. It has to show
-us in what way the different classes, orders, families, genera, and
-species of the animal and vegetable kingdoms correspond with the
-different branches, twigs, and groups of twigs of the pedigree. Every
-wider and higher category or stage of the system (for example a class,
-or an order) comprises a number of larger and stronger branches of the
-pedigree; every narrower and lower category (for example a genus, or a
-species) only a smaller and thinner group of twigs. It is only when we
-thus view the natural system as a pedigree that we perceive its true
-value. (Gen. Morph. ii. Plate XVII. p. 397.)
-
-Since we hold fast this genealogical conception of the Organic System,
-to which alone undoubtedly the future of classificatory Zoology and
-Botany belongs, we should now turn our attention to one of the most
-essential, but also one of the most difficult, tasks of the
-"non-miraculous history of creation," namely, to the actual construction
-of the Organic Pedigree. Let us see how far we are already able to point
-out all the different organic forms as the divergent descendants of a
-single or of some few common original forms. But how can we construct
-the actual pedigree of the animal and vegetable group of forms from our
-knowledge of them, at present so scanty and fragmentary? The answer to
-this question lies in what we have already remarked of the parallelism
-of the three series of development--in the important causal relation
-which connects the palaeontological development of all organic tribes
-with the embryological development of individuals, and with the
-systematic development of groups.
-
-In order to accomplish our task we shall first have to direct our
-attention to _palaeontology_, or _the science of petrifactions_. For if
-the Theory of Descent is really true, if the petrified remains of
-formerly living animals and plants really proceed from the extinct
-primaeval ancestors and progenitors of the present organisms, then,
-without anything else, the knowledge and comparison of petrifactions
-ought to disclose to us the pedigree of organisms. However simple and
-clear this may seem in theory, the task becomes extremely hard and
-complicated when it is actually taken in hand. Its practical solution
-would be very difficult even if the petrifactions were to any extent
-completely preserved. But this is by no means the case. The obvious
-records of creation which lie buried in petrifactions are imperfect
-beyond all measure. Hence it is necessary critically to examine these
-records, and to determine the value which petrifactions possess for the
-history of the development of organic tribes. As I have previously
-discussed the general importance of petrifactions as the records of
-creation, when we were considering Cuvier's merits in the science of
-fossils, we may now at once examine the conditions and circumstances
-under which the remains of organic bodies became petrified and preserved
-in a more or less recognizable form.
-
-As a rule we find petrifactions or fossils enclosed only in those stones
-which have been deposited in layers as mud by water, and which are on
-that account called neptunic, stratified, or sedimentary rocks. The
-deposition of such strata could of course only commence after the
-condensation of watery vapour into liquid water had taken place in the
-course of the earth's history. After that period, which we considered in
-our last chapter, not only did life begin on the earth, but also an
-uninterrupted and exceedingly important transformation of the rigid
-inorganic crust of the earth. The water began that extremely important
-mechanical action by which the surface of the earth is perpetually,
-though slowly, transformed. I may surely presume that it is generally
-known what an extremely important influence, in this respect, is even
-yet exercised by water at every moment. As it falls down as rain,
-trickling through the upper strata of the earth's crust, and flowing
-down from heights into hollows, it chemically dissolves different
-mineral parts of the ground, and mechanically washes away the loose
-particles. In flowing down from mountains water carries their debris
-into the plains, or deposits it as mud in stagnant lakes. Thus it
-continually works at lowering mountains and filling up valleys. In like
-manner the breakers of the sea work uninterruptedly at the destruction
-of the coasts and at filling up the bottom of the sea with the debris
-they wash down. The action of water alone, if it were not counteracted
-by other circumstances, would in time level the whole earth. There can
-be no doubt that the mountain masses--which are annually carried down as
-mud into the sea, and deposited on its floor--are so great that in the
-course of a longer or shorter period, say a few millions of years, the
-surface of the earth would be completely levelled and become enclosed by
-a continuous sheet of water. That this does not happen is owing to the
-perpetual volcanic action of the fiery-fluid centre of the earth. The
-surging of the melted nucleus against the firm crust necessitates
-continual alternations of elevation and depression on the different
-parts of the earth's surface. These elevations and depressions for the
-most part take place very slowly; but, as they continue for thousands of
-years, by the combined effect of small, interrupted movements, they
-produce results no less grand than does the counteracting and levelling
-action of water.
-
-Since the elevations and depressions of the different parts of the
-earth alternate with one another in the course of millions of years,
-first this and then that part of the earth's surface is above or below
-the level of the sea. I have already given examples of this in the
-preceding chapter (vol. i. p. 361). Hence, in all probability, there is
-no part of the outer crust of the earth which has not been repeatedly
-above and also below the level of the sea. This repeated change explains
-the variety and the different composition of the numerous neptunic
-strata of rocks, which in most places have been deposited one above
-another in considerable thickness. In the different periods of the
-earth's history during which these deposits took place there lived
-various and different populations of animals and plants. When their dead
-bodies sank to the bottom of the waters, the forms of the bodies
-impressed themselves upon the soft mud, and imperishable parts, such as
-hard bones, teeth, shells, etc., became enclosed in it uninjured. These
-were preserved in the mud, which condensed them into neptunic rock, and
-as petrifactions they now serve to characterise the respective strata.
-By a careful comparison of the different strata lying one above another,
-and the petrifactions preserved in them, it has become possible to
-decide the relative age of the strata and groups of strata, and to
-establish, by direct observation, the principal eras of phylogeny, that
-is to say, the stages in history of the development of animal and
-vegetable tribes.
-
-The different strata of neptunic rocks deposited one above another,
-which are composed in very various ways of limestone, clay, and sand,
-geologists have grouped together into an ideal System or Series, which
-corresponds with the whole course of the organic history of the earth,
-or with that portion of the earth's history during which organic life
-existed. Just as so-called "universal history" falls into larger and
-smaller periods, which are characterized by the conditions of
-development of the most important nations at the respective epochs, and
-are separated from one another by great events, so we also divide the
-infinitely longer organic history of the earth into a series of greater
-and less periods. Each of these periods is distinguished by a
-characteristic flora and fauna, and by the specially strong development
-of certain vegetable or animal groups, and each is separated from the
-preceding and succeeding period by a striking change in the character of
-its animal and vegetable inhabitants.
-
-In relation to the following survey of the historical course of
-development which the large animal and vegetable tribes have passed
-through, it will be desirable to say a few words first as to the
-systematic classification of the neptunic groups of strata, and the
-larger and smaller periods corresponding to them. As will be seen
-directly, we are able to divide the whole of the sedimentary rocks lying
-one above another into five main groups or periods, each period into
-several subordinate groups of strata or _systems_, and each system of
-strata again into still smaller groups or _formations_; finally, each
-formation can again be divided into stages or sub-formations, and each
-of these again into still smaller layers or beds. Each of the five great
-rock-groups was deposited during a great division of the earth's
-history, during a long _era_ or _epoch_; each system during a shorter
-_period_; each formation during a still shorter _period_. In thus
-reducing the periods of the organic history of the earth, and the
-neptunic strata containing petrifactions deposited during those periods
-into a connected system, we proceed exactly like the historian who
-divides the history of nations into the three main divisions of
-Antiquity, the Middle Ages, and Modern Times, and each of those sections
-again into subordinate periods and epochs. But the historian by this
-sharp systematic division, and by fixing the boundary of the periods by
-particular dates, only seeks to facilitate his survey, and in no way
-means to deny the uninterrupted connection of events and the development
-of nations. Exactly the same qualification applies to our systematic
-division, specification, or classification of the organic history of the
-earth. Here, too, a continuous thread runs through the series of events
-unbroken. We must therefore distinctly protest against the idea that by
-sharply bounding the larger and smaller groups of strata, and the
-periods corresponding with them, we in any way wish to adopt Cuvier's
-doctrine of terrestrial revolutions, and of repeated new creations of
-organic populations. That this erroneous doctrine has long since been
-completely refuted by Lyell, I have already mentioned. (Compare vol. i.
-p. 127.)
-
-The five great main divisions of the organic history of the earth, or
-the palaeontological history of development, we call the primordial,
-primary, secondary, tertiary, and quaternary epochs. Each is distinctly
-characterized by the predominating development of certain animal and
-vegetable groups in it, and we might accordingly symbolically designate
-the five epochs, on the one hand by the names of the groups of the
-vegetable kingdom, and on the other hand by those of the different
-classes of vertebrate animals. In this case the _first_, or primordial
-epoch, would be the era of the Tangles (Algae) and skull-less
-Vertebrates; the _second_, or primary epoch, that of the Ferns and
-Fishes; the _third_, or secondary epoch, that of Pine Forests and
-Reptiles; the _fourth_, or tertiary epoch, that of Foliaceous Forests
-and of Mammals; finally, the _fifth_, or quaternary epoch, the era of
-Man, and his Civilization. The divisions or _periods_ which we
-distinguish in each of the five _long eras_ (p. 14) are determined by
-the different _systems_ of strata into which each of the five great
-_rock-groups_ is divided (p. 15). We shall now take a cursory glance at
-the series of these systems, and at the same time at the populations of
-the five great epochs.
-
-The first and longest division of the organic history of the earth is
-formed by the _primordial epoch_, or _the era of the Tangle Forests_. It
-comprises the immense period from the first spontaneous generation, from
-the origin of the first terrestrial organism, to the end of the Silurian
-system of deposits. During this immeasurable space of time, which in all
-probability was much longer than all the other four epochs taken
-together, the three most extensive of all the neptunic systems of strata
-were deposited, namely, the _Laurentian_, upon that the _Cambrian_, and
-upon that the _Silurian_ system. The approximate thickness or size of
-these three systems together amounts to 70,000 feet. Of these about
-30,000 belong to the Laurentian, 18,000 to the Cambrian, and 22,000 to
-the Silurian system. The average thickness of all the four other rock
-groups, the primary, secondary, tertiary, and quaternary, taken
-together, may amount at most to 60,000 feet; and from this fact alone,
-apart from many other reasons, it is evident that the duration of the
-primordial period was probably much longer than the duration of all the
-subsequent periods down to the present day. Many thousands of millions
-of years were required to deposit such masses of strata. Unfortunately,
-by far the largest portion of the primordial group of strata is in the
-metamorphic state (which we shall directly explain), and consequently
-the petrifactions contained in them--the most ancient and most important
-of all--have, to a great extent, been destroyed and become
-unrecognisable. Only in one portion of the Cambrian strata have
-petrifactions been preserved in a recognizable condition and in large
-quantities. The most ancient of all distinctly preserved petrifactions
-has been found in the lowest Laurentian strata (in the Ottawa
-formation), which I shall afterwards have to speak of as the "Canadian
-Life's-dawn" (Eozoon canadense).
-
-Although only by far the smaller portion of the primordial or
-archilithic petrifactions are preserved to us in a recognizable
-condition, still they possess the value of inestimable documents of the
-most ancient and obscure times of the organic history of the earth. What
-seems to be shown by them, in the first place, is that during the whole
-of this immense period there existed only inhabitants of the waters. As
-yet, at any rate, among all archilithic petrifactions, not a single one
-has been found which can with certainty be regarded as an organism which
-has lived on land. All the vegetable remains we possess of the
-primordial period belong to the lowest of all groups of plants, to the
-class of Tangles or Algae, living in water. In the warm primaeval sea,
-these constituted the forests of the period, of the richness of which in
-forms and density we may form an approximate idea from their present
-descendants, the tangle forests of the Atlantic Sargasso sea. The
-colossal tangle forests of the archilithic period supplied the place of
-the forest vegetation of the mainland, which was then utterly wanting.
-All the animals, also, whose remains have been found in archilithic
-strata, like the plants, lived in water. Only crustacea are met with
-among the animals with articulated feet, as yet no spiders and no
-insects. Of vertebrate animals, only a very few remains of fishes are
-known as having been found in the most recent of all primordial strata,
-in the upper Silurian. But the headless vertebrate animals, which we
-call _skull-less_, or _Acrania_, and out of which fishes must have been
-developed, we suppose to have lived in great numbers during the
-primordial epoch. Hence we may call it after the _Acrania_ as well as
-after the _Tangles_.
-
-The _primary epoch_, or _the era of Fern Forests_, the second main
-division of the organic history of the earth, which is also called the
-palaeolithic or palaeozoic period, lasted from the end of the Silurian
-formation of strata to the end of the Permian formation. This epoch was
-also of very long duration, and again falls into three shorter periods,
-during which three great systems of strata were deposited, namely,
-first, the _Devonian_ system, or the old red sandstone; upon that, the
-_Carboniferous_, or coal system; and upon this, the _Permian_ system.
-The average thickness of these three systems taken together may amount
-to about 42,000 feet, from which we may infer the immense length of time
-requisite for their formation.
-
-The Devonian and Permian formations are especially rich in remains of
-fishes, of primaeval fish as well as enamelled fish (Ganoids), but the
-bony fish (Teleostei) are absent from the strata of the primary epoch.
-In coal are found the most ancient remains of animals living on land,
-both of articulated animals (spiders and insects) as well as of
-vertebrate animals (amphibious animals, like newts and frogs). In the
-Permian system there occur, in addition to the amphibious animals, the
-more highly-developed reptiles, and, indeed, forms nearly related to our
-lizards (Proterosaurus, etc.). But, nevertheless, we may call the
-primary epoch that of _Fishes_, because these few amphibious animals and
-reptiles are insignificant in comparison with the immense mass of
-palaeozoic fishes. Just as Fishes predominate over the other vertebrate
-animals, so _Ferns_, or Filices, predominate among the plants of this
-epoch, and, in fact, real ferns and tree ferns (leafed ferns, or
-Phylopteridae), as well as bamboo ferns (Calamophytae) and scaled ferns
-(Lepidophytae). These ferns, which grew on land, formed the chief part of
-the dense palaeolithic island forests, the fossil remains of which are
-preserved to us in the enormously large strata of coal of the
-Carboniferous system, and in the smaller strata of coal of the Devonian
-and Permian systems. We are thus justified in calling the primary epoch
-either the era of _Ferns_ or that of _Fishes_.
-
-The third great division of the palaeontological history of development
-is formed by the _secondary epoch_, or the _era of Pine Forests_, which
-is also called the mesolithic or mesozoic epoch. It extends from the end
-of the Permian system to the end of the Chalk formation, and is again
-divided into three great periods. The stratified systems deposited
-during this period are, first and lowest, the _Triassic_ system, in the
-middle the _Jura_ system, and at the top the _Cretaceous_ system. The
-average thickness of these three systems taken together is much less
-than that of the primary group, and amounts as a whole only to about
-15,000 feet. The secondary epoch can accordingly in all probability not
-have been half so long as the primary epoch.
-
-Just as Fishes prevailed in the primary epoch, _Reptiles_ predominated
-in the secondary epoch over all other vertebrate animals. It is true
-that during this period the first birds and mammals originated; at that
-time, also, there existed important amphibious animals, especially the
-gigantic Labyrinthodonts, in the sea the wonderful sea-dragons, or
-Halisaurii, swam about, and the first fish with bones were associated
-with the many primaeval fishes (Sharks) and enamelled fish (Ganoids) of
-the earlier times; but the very variously developed kinds of reptiles
-formed the predominating and characteristic class of vertebrate animals
-of the secondary epoch. Besides those reptiles which were very nearly
-related to the present living lizards, crocodiles, and turtles, there
-were, during the mesolithic period, swarms of grotesquely shaped
-dragons. The remarkable flying lizards, or Pterosaurii, and the colossal
-land-dragons, or Dinosaurii, of the secondary epoch, are peculiar, as
-they occur neither in the preceding nor in the succeeding epochs. The
-secondary epoch may be called the era of _Reptiles_; but on the other
-hand, it may also be called the era of _Pine Forests_, or more
-accurately, of the _Gymnosperms_, that is, the epoch of _plants having
-naked seeds_. For this group of plants, especially as represented by the
-two important classes--the pines, or _Coniferae_, and the palm-ferns, or
-_Cycadeae_--during the secondary epoch constituted a predominant part of
-the forests. But towards the end of the epoch (in the Chalk period) the
-plants of the pine tribe gave place to the leaf-bearing forests which
-then developed for the first time.
-
-
-SURVEY
-
-_Of the Palaeontological Periods, or of the Greater Divisions of the
-Organic History of the Earth._
-
-
-I. _First Epoch_: ARCHILITHIC ERA. _Primordial Epoch._
-
-(Era of Skull-less Animals and Forests of Tangles.)
-
-  1. Older Primordial Period     or    Laurentian Period.
-  2. Middle Primordial Period    "     Cambrian Period.
-  3. Later Primordial Period     "     Silurian Period.
-
-
-II. _Second Epoch_: PALAEOLITHIC ERA. _Primary Epoch._
-
-(Era of Fish and Fern Forests.)
-
-  4. Older Primary Period    or    Devonian Period.
-  5. Mid Primary Period      "     Coal Period.
-  6. Later Primary Period    "     Permian Period.
-
-
-III. _Third Epoch_: MESOLITHIC ERA. _Secondary Epoch._
-
-(Era of Reptiles and Pine Forests.)
-
-  7. Older Secondary Period     or    Trias Period.
-  8. Middle Secondary Period    "     Jura Period.
-  9. Later Secondary Period     "     Chalk Period.
-
-
-IV. _Fourth Epoch_: CAENOLITHIC ERA. _Tertiary Epoch._
-
-(Era of Mammals and Leaf Forests.)
-
-  10. Older Tertiary Period     or    Eocene Period.
-  11. Newer Tertiary Period     "     Miocene Period.
-  12. Recent Tertiary Period    "     Pliocene Period.
-
-
-V. _Fifth Epoch_: ANTHROPOLITHIC ERA. _Quaternary Epoch._
-
-(Era of Man and Cultivated Forests.)
-
-  13. Older Quaternary Period     or    Ice or Glacial Period.
-  14. Newer Quaternary Period     "     Post Glacial Period.
-  15. Recent Quaternary Period    "     Period of Culture.
-
-(The Period of Culture is the Historical Period, or the Period of
-Tradition.)
-
-SURVEY
-
-_Of the Palaeontological Formations, or those Strata of the Earth's Crust
-containing Petrifactions._
-
-
-  --------------------+-------------------+----------------------+--------------
-     _Rock-Groups._   |    _Systems._     |    _Formations._     | _Synonyms of
-                      |                   |                      |  Formations._
-  --------------------+-------------------+----------------------+-------------
-  V. _Quaternary      {                                          |
-     Group_,          { XIV. Recent       { 36. _Present_        | Upper alluvial
-     or               { (Alluvium)        { 35. _Recent_         | Lower alluvial
-     Anthropolithic   {                                          |
-     (Anthropozoic)   { XIII. Pleistocene { 34. _Post glacial_   | Upper diluvial
-     groups of        { (Diluvium)        { 33. _Glacial_        | Lower diluvial
-     strata           {                                          |
-
-
-  IV. _Tertiary       { XII. Pliocene     { 32. _Arvernian_      | Upper pliocene
-      Group_,         { (Late tertiary)   { 31. _Sub-Appenine_   | Lower pliocene
-      or              {                                          |
-      Caenolithic      { XI. Miocene       { 30. _Falunian_       | Upper miocene
-      (Caenozoic)      { (New tertiary)    { 29. _Limburgian_     | Lower miocene
-      groups of       {                                          |
-      strata          {                   { 28. _Gypsum_         | Upper eocene
-                      {   X. Eocene       { 27. _Nummulitic_     | Mid eocene
-                      { (Old tertiary)    { 26. _London clay_    | Lower eocene
-
-
-                      {                   { 25. _White chalk_    | Upper cretaceous
-                      { IX. Cretaceous    { 24. _Green sand_     | Mid cretaceous
-                      {                   { 23. _Neocomian_      | Lower cretaceous
-  III. _Secondary     {                   { 22. _Wealden_        | The Kentish Weald
-       Group_,        {
-       or             {                   { 21. _Portlandian_    | Upper oolite
-       Mesolithic     {  VIII. Jura       { 20. _Oxfordian_      | Mid oolite
-       (Mesozoic)     {                   { 19. _Bath_           | Lower oolite
-       groups of      {                   { 18. _Lias_           | Lias formation
-       strata         {
-                      {                   { 17. _Keuper_         | Upper trias
-                      {  VII. Trias       { 16. _Muschel-kalk_   | Mid trias
-                      {                   { 15. _Bunter sand_    | Lower trias
-
-
-                      { VI. Permian       { 14. _Zechstein_      | Upper Permian
-  II. _Primary        {                   { 13.                  | Lower Permian
-       Group_,        {                   { 12. _Carboniferous   |
-       or             { V. Carbonic              sandstone_      | Upper carbonic
-       Palaeolithic    {     (coal)        { 11. _Carboniferous   |
-      (Palaeozoic)     {                   {       limestone_     | Lower carbonic
-       groups of      { IV. Devonian      { 10. _Pilton_         | Upper Devonian
-       strata         {(Old red sandstone){  9. _Ilfracombe_     | Mid Devonian
-                                          {  8. _Linton_         | Lower Devonian
-
-
-  I. _Primordial     {                    {  7. _Ludlow_         | Upper Silurian
-     Group_,         { III. Silurian      {  6. _Llandovery_     | Mid Silurian
-     or              {                    {  5. _Llandeilo_      | Lower Silurian
-     Archilithic     {
-     (Archizoic)     { II. Cambrian       {  4. _Potsdam_        | Upper Cambrian
-     groups of       {                    {  3. _Longmynd_       | Lower Cambrian
-     strata          {
-                     { I. Laurentian      {  2. _Labrador_       | Upper Laurentian
-                     {                    {  1. _Ottawa_         | Lower Laurentian
-
-
-The fourth main division of the organic history of the earth, the
-_tertiary epoch_, or _era of Leafed Forests_, is much shorter and less
-peculiar than the three first epochs. This epoch, which is also called
-the caenolithic or caenozoic epoch, extended from the end of the
-cretaceous system to the end of the pliocene system. The strata
-deposited during it amount only to a thickness of about 3000 feet, and
-consequently are much inferior to the three first great groups. The
-three systems also into which the tertiary period is subdivided are very
-difficult to distinguish from one another. The oldest of them is called
-_eocene_, or old tertiary; the newer _miocene_, or mid tertiary; and the
-last is the _pliocene_, or later tertiary system.
-
-The whole population of the tertiary epoch approaches much nearer, on
-the whole as well as in detail, to that of the present time than is the
-case in the preceding epochs. From this time the class of _Mammals_
-greatly predominates over all other vertebrate animals. In like manner,
-in the vegetable kingdom, the group--so rich in forms--of the
-_Angiosperms_, or _plants with covered seeds_, predominates, and its
-_leafy forests_ constitute the characteristic feature of the tertiary
-epoch. The group of the Angiosperms consists of the two classes of
-single-seed-lobed plants, or _Monocotyledons_, and the double-seed-lobed
-plants, or _Dicotyledons_. The Angiosperms of both classes had, it is
-true, made their appearance in the Cretaceous period, and mammals had
-already occurred in the Jurassic period, and even in the Triassic
-period; but both groups, the mammals and the plants with enclosed seeds,
-did not attain their peculiar development and supremacy until the
-tertiary epoch, so that it may justly be called after them.
-
-The fifth and last main division of the organic history of the earth is
-the _quaternary epoch, or era of Civilization_, which in comparison with
-the length of the four other epochs almost vanishes into nothing, though
-with a comical conceit we usually call its record the "history of the
-world." As the period is characterized by the development of _Man_ and
-his _Culture_, which has influenced the organic world more powerfully
-and with greater transforming effect than have all previous conditions,
-it may also be called the era of Man, the anthropolithic or anthropozoic
-period. It might also be called the era of Cultivated Forests, or
-Gardens, because even at the lowest stage of human civilization man's
-influence is already perceptible in the utilization of forests and their
-products, and therefore also in the physiognomy of the landscape. The
-commencement of this era, which extends down to the present time, is
-geologically bounded by the end of the pliocene stratification.
-
-The neptunic strata which have been deposited during the comparatively
-short quaternary epoch are very different in different parts of the
-earth, but they are mostly of very slight thickness. They are reduced to
-two "systems," the older of which is designated the _diluvial_, or
-_pleistocene_, and the later the _alluvial_, or _recent_. The diluvial
-system is again divided into two "formations," the older _glacial_ and
-the more recent _post glacial_ formations. For during the older diluvial
-period there occurred that extremely remarkable decrease of the
-temperature of the earth which led to an extensive glaciation of the
-temperate zones. The great importance which this "ice" or "glacial
-period" has exercised on the geographical and topographical distribution
-of organisms has already been explained in the preceding chapter (vol.
-i. p. 365). But the _post glacial period_, or the more recent diluvial
-period, during which the temperature again increased and the ice
-retreated towards the poles, was also highly important in regard to the
-present state of chorological relations.
-
-The biological characteristic of the quaternary epoch lies essentially
-in the development and dispersion of the human organism and his culture.
-Man has acted with a greater transforming, destructive, and modifying
-influence upon the animal and vegetable population of the earth than any
-other organism. For this reason, and not because we assign to man a
-privileged exceptional position in nature in other matters, we may with
-full justice designate the development of man and his civilization as
-the beginning of a special and last main division of the organic history
-of the earth. It is probable indeed that the corporeal development of
-primaeval man out of man-like apes took place as far back as the earlier
-pliocene period, perhaps even in the miocene tertiary period. But the
-actual development of _human speech_, which we look upon as the most
-powerful agency in the development of the peculiar characteristics of
-man and his dominion over other organisms, probably belongs to that
-period which on geological grounds is distinguished from the preceding
-pliocene period as the pleistocene or diluvial. In fact the time which
-has elapsed from the development of human speech down to the present
-day, though it may comprise many thousands and perhaps hundreds of
-thousands of years, almost vanishes into nothing as compared with the
-immeasurable length of the periods which have passed from the beginning
-of organic life on the earth down to the origin of the human race.
-
-The tabular view given on page 15 shows the succession of the
-palaeontological rock-groups, systems, and formations, that is, the
-larger and smaller neptunic groups of strata, which contain
-petrifactions, from the uppermost, or Alluvial, down to the lowest, or
-Laurentian, deposits. The table on page 14 presents the historical
-division of the corresponding eras of the larger and smaller
-palaeontological periods, and in a reversed succession, from the most
-ancient Laurentian up to the most recent Quaternary period.
-
-Many attempts have been made to make an approximate calculation of the
-number of thousands of years constituting these periods. The thickness
-of the strata has been compared, which, according to experience, is
-deposited during a century, and which amounts only to some few lines or
-inches, with the whole thickness of the stratified masses of rock, the
-succession of which we have just surveyed. This thickness, on the whole,
-may on an average amount to about 130,000 feet; of these 70,000 belong
-to the primordial, or archilithic; 42,000 to the primary, or
-palaeolithic; 15,000 to the secondary, or mesolithic; and finally only
-3,000 to the tertiary, or caenolithic group. The very small and scarcely
-appreciable thickness of the quaternary, or anthropolithic deposit
-cannot here come into consideration at all. On an average, it may at
-most be computed as from 500 to 700 feet. But it is self evident that
-all these measurements have only an average and approximate value, and
-are meant to give only a rough survey of the _relative_ proportion of
-the systems of strata and of the spaces of time corresponding with them.
-
-Now, if we divide the whole period of the organic history of the
-earth--that is, from the beginning of life on the earth down to the
-present day--into a hundred equal parts, and if then, corresponding to
-the thickness of the systems of strata, we calculate the relative
-duration of the time of the five main divisions or periods according to
-percentages, we obtain the following result:--
-
-
-    I. Archilithic, or primordial period       53.6
-   II. Palaeolithic, or primary period          32.1
-  III. Mesolithic, or secondary period         11.5
-   IV. Caenolithic, or tertiary period           2.3
-    V. Anthropolithic, or quaternary period     0.5
-                                              -----
-                                      Total   100.0
-
-
-According to this, the length of the archilithic period, during which no
-land-living animals or plants as yet existed, amounts to more than one
-half, more than 53 per cent.; on the other hand the length of the
-anthropolithic era, during which man has existed, amounts to scarcely
-one-half per cent. of the whole length of the organic history of the
-earth. It is, however, quite impossible to calculate the length of these
-periods, even approximately, by years.
-
-The thickness of the strata of mud at present deposited during a
-century, and which has been used as a basis for this calculation, is of
-course quite different in different parts of the earth under the
-different conditions in which these deposits take place. It is very
-slight at the bottom of the deep sea, in the beds of broad rivers with a
-short course, and in inland seas which receive very scanty supplies of
-water. It is comparatively great on the sea-shores exposed to strong
-breakers, at the estuaries of large rivers with long courses, and in
-inland seas with copious supplies of water. At the mouth of the
-Mississippi, which carries with it a considerable amount of mud, in the
-course of 100,000 years about 600 feet would be deposited. At the bottom
-of the open sea, far away from the coasts, during this long period only
-some few feet of mud would be deposited. Even on the sea-shores where a
-comparatively large quantity of mud is deposited the thickness of the
-strata formed during the course of a century may after all amount to no
-more than a few inches or lines when condensed into solid stone. In any
-case, however, all calculations based upon these comparisons are very
-unsafe, and we cannot even approximately conceive the enormous length of
-the periods which were requisite for the formation of the systems of
-neptunic strata. Here we can apply only relative, not absolute,
-measurements of time.
-
-Moreover, we should entirely err were we to consider the size of these
-systems of strata alone as the measure of the actual space of time which
-has elapsed during the earth's history. For the elevations and
-depressions of the earth's crust have perpetually alternated with one
-another, and the mineralogical and palaeontological difference--which is
-perceived between each two succeeding systems of strata, and between
-each two of their formations at any particular spot--corresponds in all
-probability with a considerable intermediate space of many thousands of
-years, during which that particular part of the earth's crust was raised
-above the water. It was only after the lapse of this intermediate
-period, when a new depression again laid the part in question under
-water, that there occurred a new deposit of earth. As, in the mean time,
-the inorganic and organic conditions on this part had undergone a
-considerable transformation, the newly-formed layer of mud was
-necessarily composed of different earthy constituents and enclosed
-different petrifactions.
-
-  IV. Tertiary Group of            |
-  Strata, 3,000 feet.              |    Eocene, Miocene, Pliocene.
-  ---------------------------------+------------------------------
-                                   |    IX. Chalk System.
-  III. Mesolithic Group of Strata. |
-                                   |
-  Deposits of the                  |    VIII. Jura System.
-  Secondary Epoch, about           |
-  15,000 feet.                     |
-                                   |   VII. Trias System.
-  ---------------------------------+------------------------------
-                                   |
-                                   |    VI. Permian System.
-  II. Palaeolithic Group of Strata. |
-                                   |
-  Deposits of the                  |     V. Coal System.
-  Primary Epoch, about             |
-  42,000 feet.                     |   IV. Devonian System.
-  ---------------------------------+------------------------------
-                                   |
-                                   |   III. Silurian System, about
-                                   |           22,000 feet.
-  I. Archilithic Group of Strata.  |
-                                   |
-  Deposits of the                  |   II. Cambrian System, about
-  Primordial Epoch, about          |           18,000 feet.
-  70,000 feet.                     |
-                                   |   I. Laurentian System, about
-                                   |           30,000 feet.
-
-
-The striking differences which so frequently occur between the
-petrifactions of two strata, lying one above another, are to be
-explained in a simple and easy manner by the supposition that the same
-part of the earth's surface has been exposed to _repeated depressions
-and elevations_. Such alternating elevations and depressions take place
-even now extensively, and are ascribed to the heaving of the fiery fluid
-nucleus against the rigid crust. Thus, for example, the coast of Sweden
-and a portion of the west coast of South America are constantly though
-slowly rising, while the coast of Holland and a portion of the east
-coast of South America are gradually sinking. The rising as well as the
-sinking takes place very slowly, and in the course of a century
-sometimes only amounts to some few lines, sometimes to a few inches, or
-at most a few feet. But if this action continues uninterruptedly
-throughout hundreds of thousands of years it is capable of forming the
-highest mountains.
-
-It is evident that elevations and depressions, such as now can be
-measured in these places, have uninterruptedly alternated one with
-another in different places during the whole course of the organic
-history of the earth. This may be inferred with certainty from the
-geographical distribution of organisms. (Compare vol. i. p. 350.) But to
-form a judgment of our palaeontological records of creation it is
-extremely important to show that permanent strata can only be deposited
-during a slow sinking of the ground under water, but not during its
-continued rising. When the ground slowly sinks more and more below the
-level of the sea, the deposited layers of mud get into continually
-deeper and quieter water, where they can become condensed into stone
-undisturbed. But when, on the other hand, the ground slowly rises, the
-newly-deposited layers of mud, which enclose the remains of plants and
-animals, again immediately come within the reach of the play of the
-waves, and are soon worn away by the force of the breakers, together
-with the organic remains which they on close. For this simple but very
-important reason, therefore, abundant layers, in which organic remains
-are preserved, can only be deposited during a continuous sinking of the
-ground. When any two different formations or strata, lying one above the
-other, correspond with two different periods of depression, we must
-assume a long period of rising between them, of which period we know
-nothing, because no fossil remains of the then living animals and plants
-could be preserved. It is evident, however, that those _periods of
-elevation_, which have passed without leaving any trace behind them,
-deserve a no less careful consideration than the greater or less
-alternating _periods of depression_, of whose organic population we can
-form an approximate idea from the strata containing petrifactions.
-Probably the former were not of shorter duration than the latter.
-
-From this alone it is apparent how imperfect our records must
-necessarily be, and all the more so since it can be theoretically proved
-that the variety of animal and vegetable life must have increased
-greatly during those very periods of elevation. For as new tracts of
-land are raised above the water, new islands are formed. Every new
-island, however, is a new centre of creation, because the animals and
-plants accidentally cast ashore there, find in the new territory, in
-the struggle for life, abundant opportunity of developing themselves
-peculiarly, and of forming new species. The formation of new species has
-evidently taken place pre-eminently during these intermediate periods,
-of which, unfortunately, no petrifactions could be preserved, whereas,
-on the contrary, during the slow sinking of the ground there was more
-chance of numerous species dying out, and of a retrogression into fewer
-specific forms. The intermediate forms between the old and the
-newly-forming species must also have lived during the periods of
-elevation, and consequently could likewise leave no fossil remains.
-
-In addition to the great and deplorable gaps in the palaeontological
-records of creation--which are caused by the periods of elevation--there
-are, unfortunately, many other circumstances which immensely diminish
-their value. I must mention here especially the _metamorphic state of
-the most ancient formations_, of those strata which contain the remains
-of the most ancient flora and fauna, the original forms of all
-subsequent organisms, and which, therefore, would be of especial
-interest. It is just these rocks--and, indeed, the greater part of the
-primordial, or archilithic strata, almost the whole of the Laurentian,
-and a large part of the Cambrian systems--which no longer contain any
-recognizable remains, and for the simple reason that these strata have
-been subsequently changed or metamorphosed by the influence of the fiery
-fluid interior of the earth. These deepest neptunic strata of the crust
-have been completely changed from their original condition by the heat
-of the glowing nucleus of the earth, and have assumed a crystalline
-state. In this process, however, the form of the organic remains
-enclosed in them has been entirely destroyed. It has been preserved only
-here and there by a happy chance, as in the case of the most ancient
-petrifactions known, the _Eozoon canadense_, from the lowest Laurentian
-strata. However, from the layers of crystalline charcoal (graphite) and
-crystalline limestone (marble), which are found deposited in the
-metamorphic rocks, we may with certainty conclude that petrified animal
-and vegetable remains existed in them in earlier times.
-
-Our record of creation is also extremely imperfect from the circumstance
-that only a small portion of the earth's surface has been accurately
-investigated by geologists, namely, England, Germany, and France. But we
-know very little of the other parts of Europe, of Russia, Spain, Italy,
-and Turkey. In the whole of Europe, only some few parts of the earth's
-crust have been laid open, by far the largest portion of it is unknown
-to us. The same applies to North America and to the East Indies. There
-some few tracts have been investigated; but of the larger portion of
-Asia, the most extensive of all continents, we know almost nothing; of
-Africa nothing, excepting the Cape of Good Hope and the shores of the
-Mediterranean; of Australia almost nothing; and of South America but
-very little. It is clear, therefore, that only quite a small portion,
-perhaps scarcely the thousandth part of the whole surface of the earth,
-has been palaeontologically investigated. We may therefore reasonably
-hope, when more extensive geological investigations are made, which are
-greatly assisted by the constructions of railroads and mines, to find a
-great number of other important petrifactions. A hint that this will be
-the case is given by the remarkable petrifactions found in those parts
-of Africa and Asia which have been minutely investigated,--the Cape
-districts and the Himalaya mountains. A series of entirely new and very
-peculiar animal forms have become known to us from the rocks of these
-localities. But we must bear in mind that the vast bottom of the
-existing oceans is at the present time quite inaccessible to
-palaeontological investigations, and that the greater part of the
-petrifactions which have lain there from primaeval times will either
-never be known to us, or at best only after the course of many thousands
-of years, when the present bottom of the ocean shall have become
-accessible by gradual elevation. If we call to mind the fact that
-three-fifths of the whole surface of the earth consists of water, and
-only two-fifths of land, it becomes plain that on this account the
-palaeontological record must always present an immense gap.
-
-But, in addition to these, there exists another series of difficulties
-in the way of palaeontology which arises from the nature of the organisms
-themselves. In the first place, as a rule only the hard and solid parts
-of organisms can fall to the bottom of the sea or of fresh waters, and
-be there enclosed in the mud and petrified. Hence it is only the bones
-and teeth of vertebrate animals, the calcareous shells of molluscs, the
-chitinous skeletons of articulated animals, the calcareous skeletons of
-star-fishes and corals, and the woody and solid parts of plants, that
-are capable of being petrified. But soft and delicate parts, which
-constitute by far the greater portion of the bodies of most organisms,
-are very rarely deposited in the mud under circumstances favourable to
-their becoming petrified, or distinctly impressing their external form
-upon the hardening mud. Now, it must be borne in mind that large classes
-of organisms, as for example the Medusae, the naked molluscs without
-shells, a large portion of the articulated animals, almost all worms,
-and even the lowest vertebrate animals, possess no firm and hard parts
-capable of being petrified. In like manner the most important parts of
-plants, such as the flowers, are for the most part so soft and tender
-that they cannot be preserved in a recognizable form. We therefore
-cannot expect to find any petrified remains of these important
-organisms. Moreover, all organisms at an early stage of life are so soft
-and tender that they are quite incapable of being petrified.
-Consequently all the petrifactions found in the neptunic stratifications
-of the earth's crust comprise altogether but a very few forms, and of
-these for the most part only isolated fragments.
-
-We must next bear in mind that the dead bodies of the inhabitants of the
-sea are much more likely to be preserved and petrified in the deposits
-of mud than those of the inhabitants of fresh water and of the land.
-Organisms living on land can, as a rule, become petrified only when
-their corpses fall accidentally into the water and are buried at the
-bottom in the hardening layers of mud. But this event depends upon very
-many conditions. We cannot therefore be astonished that by far the
-majority of petrifactions belong to organisms which have lived in the
-sea, and that of the inhabitants of the land proportionately only very
-few are preserved in a fossil state. How many contingencies come into
-play here we may infer from the single fact that of many fossil mammals,
-in fact of all the mammals of the secondary, or mesozoic epoch, nothing
-is known except the lower jawbone. This bone is in the first place
-comparatively solid, and in the second place very easily separates
-itself from the dead body, which floats on the water. Whilst the body is
-driven away and dissolved by the water, the lower jawbone falls down to
-the bottom of the water and is there enclosed in the mud. This explains
-the remarkable fact that in a stratum of limestone of the Jurassic
-system near Oxford, in the slates of Stonesfield, as yet only the lower
-jawbones of numerous pouched animals (Marsupials) have been found. They
-are the most ancient mammals known, and of the whole of the rest of
-their bodies not a single bone exists. The opponents of the theory of
-development, according to their usual logic, would from this fact be
-obliged to draw the conclusion that the lower jawbone was the only bone
-in the body of those animals.
-
-Footprints are very instructive when we attempt to estimate the many
-accidents which so arbitrarily influence our knowledge of fossils; they
-are found in great numbers in different extensive layers of sandstone;
-for example, in the red sandstone of Connecticut, in North America.
-These footprints were evidently made by vertebrate animals, probably by
-reptiles, of whose bodies not the slightest trace has been preserved.[1]
-The impressions which their feet have left on the mud alone betray the
-former existence of these otherwise unknown animals.
-
-The accidents which, besides these, determine the limits of our
-palaeontological knowledge, may be inferred from the fact that we know of
-only one or two specimens of very many important petrifactions. It is
-not ten years since we became acquainted with the imperfect impression
-of a bird in the Jurassic or Oolitic system, the knowledge of which
-has been of the very greatest importance for the phylogeny of the whole
-class of birds. All birds previously known presented a very uniformly
-organized group, and showed no striking transitional forms to other
-vertebrate classes, not even to the nearly related reptiles. But that
-fossil bird from the Jura possessed not an ordinary bird's tail, but a
-lizard's tail, and thus confirmed what had been conjectured upon other
-grounds, namely, the derivation of birds from lizards. This single
-fossil has thus essentially extended not only our knowledge of the age
-of the class of birds, but also of their blood relationship to reptiles.
-In like manner our knowledge of other animal groups has been often
-essentially modified by the accidental discovery of a single fossil. The
-palaeontological records must necessarily be exceedingly imperfect,
-because we know of so very few examples, or only mere fragments of very
-many important fossils.
-
-Another and very sensible gap in these records is caused by the
-circumstance that the _intermediate forms_ which connect the different
-species have, as a rule, not been preserved, and for the simple reason
-that (according to the principle of divergence of character) they were
-less favoured in the struggle for life than the most divergent
-varieties, which had developed out of one and the same original form.
-The intermediate links have, on the whole, always died out _rapidly_,
-and have but rarely been preserved as fossils. On the other hand, the
-most divergent forms were able to maintain themselves in life for a
-longer period as independent species, to propagate more numerously, and
-consequently to be more readily petrified. But this does not exclude the
-fact that in _some_ cases the connecting intermediate forms of the
-species have been preserved so perfectly petrified, that even now they
-cause the greatest perplexity and occasion endless disputes among
-systematic palaeontologists about the arbitrary limits of species.
-
-An excellent example of this is furnished by the celebrated and very
-variable fresh-water snail from the Stuben Valley, near Steinheim, in
-Wuertemburg, which has been described sometimes as _Paludina_, sometimes
-as _Valvata_, and sometimes as _Planorbis multiformis_. The snow-white
-shells of these small snails constitute more than half of the mass of
-the tertiary limestone hills, and in this one locality show such an
-astonishing variety of forms, that the most divergent extremes might be
-referred to at least twenty entirely different species. But all these
-extreme forms are united by such innumerable intermediate forms, and
-they lie so regularly above and beside one another, that Hilgendorf was
-able, in the clearest manner, to unravel the pedigree of the whole group
-of forms. In like manner, among very many other fossil species (for
-example, many ammonites, terebratulae, sea urchins, lily encrinites,
-etc.) there are such masses of connecting intermediate forms, that they
-reduce the "dealers in fossil species" to despair.
-
-When we weigh all the circumstances here mentioned, the number of which
-might easily be increased, it does not appear astonishing that the
-natural accounts or records of creation formed by petrifactions are
-extremely defective and incomplete. But nevertheless, the petrifactions
-actually discovered are of the greatest value. Their significance is of
-no less importance to the natural history of creation than the
-celebrated inscription on the Rosetta stone, and the decree of Canopus,
-are to the history of nations--to archaeology and philology. Just as it
-has become possible by means of these two most ancient inscriptions to
-reconstruct the history of ancient Egypt, and to decipher all
-hieroglyphic writings, so in many cases a few bones of an animal, or
-imperfect impressions of a lower animal or vegetable form, are
-sufficient for us to gain the most important starting-points in the
-history of the whole group, and in the search after their pedigree. A
-couple of small back teeth, which have been found in the Keuper
-formation of the Trias, have of themselves alone furnished a sure proof
-that mammals existed even in the Triassic period.
-
-Of the incompleteness of the geological accounts of creation, Darwin,
-agreeing with Lyell, the greatest of all recent geologists, says:--
-
-"I look at the geological record as a history of the world imperfectly
-kept, and written in a changing dialect; of this history we possess the
-last volume alone, relating only to two or three countries. Of this
-volume, only here and there a short chapter has been preserved; and of
-each page, only here and there a few lines. Each word of the
-slowly-changing language, more or less different in the successive
-chapters, may represent the forms of life which are entombed in our
-consecutive formations, and which falsely appear to us to have been
-abruptly introduced. On this view, the difficulties above discussed are
-greatly diminished, or even disappear."--_Origin of Species_, 6th
-Edition, p. 289.
-
-If we bear in mind the exceeding incompleteness of palaeontological
-records, we shall not be surprised that we are still dependent upon so
-many uncertain hypotheses when actually endeavouring to sketch the
-pedigree of the different organic groups. However, we fortunately
-possess, besides fossils, other records of the history of the origin of
-organisms, which in many cases are of no less value, nay, in several
-cases are of much greater value, than fossils. By far the most important
-of these other records of creation is, without doubt, _ontogeny_, that
-is, the history of the development of the organic individual (embryology
-and metamorphology). It briefly repeats in great and marked features the
-series of forms which the ancestors of the respective individuals have
-passed through from the beginning of their tribe. We have designated the
-palaeontological history of the development of the ancestors of a living
-form as the history of a tribe, or _phylogeny_, and we may therefore
-thus enunciate this exceedingly important _biogenetic fundamental
-principle_: "_Ontogeny is a short and quick repetition, or
-recapitulation, of Phylogeny, determined by the laws of Inheritance and
-Adaptation_." As every animal and every plant from the beginning of its
-individual existence passes through a series of different forms, it
-indicates in rapid succession and in general outlines the long and
-slowly changing series of states of form which its progenitors have
-passed through from the most ancient times. (Gen. Morph. ii. 6, 110,
-300.)
-
-It is true that the sketch which the ontogeny of organisms gives us of
-their phylogeny is in most cases more or less obscured, and all the more
-so the more Adaptation, in the course of time, has predominated over
-Inheritance, and the more powerfully the law of abbreviated inheritance,
-and the law of correlative adaptation, have exerted their influence.
-However, this does not lessen the great value which the actual and
-faithfully preserved features of that sketch possess. _Ontogeny is of
-the most inestimable value for the knowledge of the earliest
-palaeontological conditions of development_, just because no petrified
-remains of the most ancient conditions of the development of tribes and
-classes have been preserved. These, indeed, could not have been
-preserved on account of the soft and tender nature of their bodies. No
-petrifactions could inform us of the fundamental and important fact
-which ontogeny reveals to us, that the most ancient common ancestors of
-all the different animal and vegetable species were quite simple cells
-like the egg-cell. No petrifaction could prove to us the immensely
-important fact, established by ontogeny, that the simple increase, the
-formation of cell-aggregates and the differentiation of those cells,
-produced the infinitely manifold forms of multicellular organisms. Thus
-ontogeny helps us over many and large gaps in palaeontology.
-
-[Illustration: Hand of Nine different Mammals. Pl. IV.
-
-_1. Man_, _2. Gorilla_, _3. Orang_, _4. Dog_, _5. Seal_, _6. Porpoise_,
-_7. Bat_, _8. Mole_, _9. Duck-bill_.]
-
-To the invaluable records of creation furnished by palaeontology and
-ontogeny are added the no less important evidences for the blood
-relationship of organisms furnished by _comparative anatomy_. When
-organisms, externally very different, nearly agree in their internal
-structure, one may with certainty conclude that the agreement has its
-foundation in Inheritance, the dissimilarity its foundation in
-Adaptation. Compare, for example, the hands and fore paws of the nine
-different animals which are represented on Plate IV., in which the bony
-skeleton in the interior of the hand and of the five fingers is visible.
-Everywhere we find, though the external forms are most different, the
-same bones, and among them the same number, position, and connection. It
-will perhaps appear very natural that the hand of _man_ (Fig. 1) differs
-very little from that of the _gorilla_ (Fig. 2) and of the
-_orang-outang_ (Fig. 3), his nearest relations. But it will be more
-surprising if the fore feet of the _dog_ also (Fig. 4), as well as the
-breast-fin (the hand) of the _seal_ (Fig. 5), and of the _dolphin_ (Fig.
-6), show essentially the same structure. And it will appear still more
-wonderful that even the wing of the _bat_ (Fig. 7), the shovel-feet of
-the _mole_ (Fig. 8), and the fore feet of the _duck-bill_
-(Ornithorhynchus) (Fig. 9), the most imperfect of all mammals, is
-composed of entirely the same bones, only their size and form being
-variously changed. Their number, the manner of their arrangement and
-connection has remained the same. (Compare also the explanation of Plate
-IV., in the Appendix.) It is quite inconceivable that any other cause,
-except the common inheritance of the part in question from common
-ancestors, could have occasioned this wonderful homology or similarity
-in the essential inner structure with such different external forms.
-Now, if we go down further in the system below the mammals, and find
-that even the wings of birds, the fore feet of reptiles and amphibious
-animals, are composed of essentially the same bones as the arms of man
-and the fore legs of the other mammals, we can, from this circumstance
-alone, with perfect certainty, infer the common origin of all these
-vertebrate animals. Here, as in all other cases, the degree of the
-internal agreement in the form discloses to us the degree of blood
-relationship.
-
-
-
-
-CHAPTER XVI.
-
-PEDIGREE AND HISTORY OF THE KINGDOM OF THE PROTISTA.
-
-
-  Special Mode of Carrying out the Theory of Descent in the
-  Natural System of Organisms.--Construction of Pedigrees.--Descent
-  of all Many-Celled from Single-Celled Organisms.--Descent of
-  Cells from Monera.--Meaning of Organic Tribes, or Phyla.--Number
-  of the Tribes in the Animal and Vegetable Kingdoms.--The
-  Monophyletic Hypothesis of Descent, or the Hypothesis of one
-  Common Progenitor, and the Polyphyletic Hypothesis of Descent,
-  or the Hypothesis of Many Progenitors.--The Kingdom of Protista,
-  or Primaeval Beings.--Eight Classes of the Protista
-  Kingdom.--Monera, Amoebae, or Protoplastae.--Whip-swimmers, or
-  Flagellata.--Ciliated-balls, or Catallacta.--Labyrinth-streamers,
-  or Labyrinthuleae.--Flint-cells, or Diatomeae.--Mucous-moulds, or
-  Myxomycetes.--Root-footers (Rhizopoda).--Remarks on the General
-  Natural History of the Protista: Their Vital Phenomena,
-  Chemical Composition, and Formation (Individuality and
-  Fundamental Form).--Phylogeny of the Protista Kingdom
-
-
-By a careful comparison of the individual and the palaeontological
-development, as also by the comparative anatomy of organisms, by the
-comparative examination of their fully developed structural
-characteristics, we arrive at the knowledge of the degrees of their
-different structural relationships. By this, however, we at the same
-time obtain an insight into their true _blood relationship_, which,
-according to the Theory of Descent, is the real reason of the structural
-relationship. Hence by collecting, comparing, and employing the
-empirical results of embryology, palaeontology, and anatomy for
-supplementing each other, we arrive at an approximate knowledge of "the
-Natural System," which, according to our views, is the _pedigree_ of
-organisms. It is true that our human knowledge, in all things
-fragmentary, is especially so in this case, on account of the extreme
-incompleteness and defectiveness of the records of creation. However, we
-must not allow this to discourage us, or to deter us from undertaking
-this highest problem of biology. Let us rather see how far it may even
-now be possible, in spite of the imperfect state of our embryological,
-palaeontological, and anatomical knowledge, to establish a probable
-scheme of the genealogical relationships of organisms.
-
-Darwin in his book gives us no answer to these special questions of the
-Theory of Descent; at the conclusion he only expresses his conjecture
-"that animals have descended from at most only four or five progenitors,
-and plants from an equal or less number." But as these few aboriginal
-forms still show traces of relationship, and as the animal and vegetable
-kingdoms are connected by intermediate transitional forms, he arrives
-afterwards at the opinion "that probably all the organic beings which
-have ever lived on the earth have descended from some one primordial
-form, into which life was first breathed by the Creator." Like Darwin,
-all other adherents of the Theory of Descent have only treated it in a
-general way, and not made the attempt to carry it out specially, and to
-treat the "Natural System" actually as the pedigree of organisms. If,
-therefore, we venture upon this difficult undertaking, we must take up
-independent ground.
-
-Four years ago I set up a number of hypothetical genealogies for the
-larger groups of organisms in the systematic introduction to my General
-History of Development (Gen. Morph. vol. ii.), and thereby, in fact,
-made the first attempt actually to construct the pedigrees of organisms
-in the manner required by the theory of development. I was quite
-conscious of the extreme difficulty of the task, and as I undertook it
-in spite of all discouraging obstacles, I claim no more than the merit
-of having made the first attempt and given a stimulus for other and
-better attempts. Probably most zoologists and botanists were but little
-satisfied with this beginning, and least so in reference to the special
-domain in which each one is specially at work. However, it is certainly
-in this case much easier to blame than to produce something better, and
-what best proves the immense difficulty of this infinitely complicated
-task is the fact that no naturalist has as yet supplied the place of my
-pedigrees by better ones. But, like all other scientific hypotheses
-which serve to explain facts, my genealogical hypotheses may claim to be
-taken into consideration until they are replaced by better ones.
-
-I hope that this replacement will very soon take place; and I wish for
-nothing more than that my first attempt may induce very many naturalists
-to establish more accurate pedigrees for the individual groups, at least
-in the special domain of the animal and vegetable kingdom which happens
-to be well known to one or other of them. By numerous attempts of this
-kind our genealogical knowledge, in the course of time, will slowly
-advance and approach more towards perfection, although it can with
-certainty be foreseen that we shall never arrive at a complete
-pedigree. We lack, and shall ever lack, the indispensable
-palaeontological foundations. The most ancient records will ever remain
-sealed to us, for reasons which have been previously mentioned. The most
-ancient organisms which arose by spontaneous generation--the original
-parents of all subsequent organisms--must necessarily be supposed to
-have been Monera--simple, soft, albuminous lumps, without structure,
-without any definite forms, and entirely without any hard and formed
-parts. They and their next offspring were consequently not in any way
-capable of being preserved in a petrified condition. But we also lack,
-for reasons discussed in detail in the preceding chapter, by far the
-greater portion of the innumerable palaeontological documents, which are
-really requisite for a safe reconstruction of the history of animal
-tribes, or phylogeny, and for the true knowledge of the pedigree of
-organisms. If we, therefore, in spite of this, venture to undertake
-their hypothetical construction, we must chiefly depend for guidance on
-the two other series of records which most essentially supplement the
-palaeontological archives. These are ontogeny and comparative anatomy.
-
-If thoughtfully and carefully we consult these most valuable records, we
-at once perceive what is exceedingly significant, namely, that by far
-the greater number of organisms, especially all higher animals and
-plants, are composed of a great number of cells, and that they originate
-out of an egg, and that this egg, in animals as well as in plants, is a
-single, perfectly simple cell--a little lump of albuminous constitution,
-in which another albuminous corpuscle, the cell-kernel, is enclosed.
-This cell containing its kernel grows and becomes enlarged. By division
-it forms an accumulation of cells, and out of these, by division of
-labour (as has previously been described), there arise the numberless
-different forms which are presented to us in the fully developed animal
-and vegetable species. This immensely important process--which we may
-follow step by step, with our own eyes, any day in the embryological
-development of any animal or vegetable individual, and which as a rule
-is by no means considered with the reverence it deserves--informs us
-more surely and completely than all petrifactions could do as to the
-original palaeontological development of all many-celled organisms, that
-is, of all higher animals and plants. For as ontogeny, or the
-embryological development of every single individual, is essentially
-only a recapitulation of phylogeny, or the palaeontological development
-of its chain of ancestors, we may at once, with full assurance, draw the
-simple and important conclusion, that _all many-celled animals and
-plants were originally derived from single-celled organisms_. The
-primaeval ancestors of man, as well as of all other animals, and of all
-plants composed of many cells, were simple cells living isolated. This
-invaluable secret of the organic pedigree is revealed to us with
-infallible certainty by the egg of animals, and by the true egg-cell of
-plants. When the opponents of the Theory of Descent assert it to be
-miraculous and inconceivable that an exceedingly complicated many-celled
-organism could, in the course of time, have proceeded from a simple
-single-celled organism, we at once reply that we may see this incredible
-miracle at any moment, and follow it with our own eyes. For the
-embryology of animals and plants visibly presents to our eyes in the
-shortest space of time the same process as that which has taken place in
-the origin of the whole tribe during the course of enormous periods of
-time.
-
-Upon the ground of embryological records, therefore, we can with full
-assurance maintain that all many-celled, as well as single-celled,
-organisms are originally descended from simple cells; connected with
-this, of course, is the conclusion that the most ancient root of the
-animal and vegetable kingdom was common to both. For the different
-primaeval "original cells" out of which the few different main groups or
-tribes have developed, only acquired their differences after a time, and
-were descended from a common "primaeval cell." But where did those few
-"original cells," or the one primaeval cell, come from? For the answer to
-this fundamental genealogical question we must return to the theory of
-plastids and the hypothesis of spontaneous generation which we have
-already discussed (vol. i. p. 327).
-
-As was then shown, we cannot imagine _cells_ to have arisen by
-spontaneous generation, but only _Monera_, those primaeval creatures of
-the simplest kind conceivable, like the still living Protamoebae,
-Protomyxae, etc. (vol. i. p. 186, Fig. 1). Only such corpuscules of mucus
-without component parts--whose whole albuminous body is as homogeneous
-in itself as an inorganic crystal, but which nevertheless fulfills the
-two organic fundamental functions of nutrition and propagation--could
-have directly arisen out of inorganic matter by autogeny at the
-beginning (we may suppose) of the Laurentian period. While some Monera
-remained at the original simple stage of formation, others gradually
-developed into cells by the inner kernel of the albuminous mass becoming
-separated from the external cell-substance. In others, by
-differentiation of the outermost layer of the cell-substance, an
-external covering (membrane, or skin) was formed round simple cytods
-(without kernel), as well as round naked cells (containing a kernel). By
-these two processes of separation in the simple primaeval mucus of the
-Moneron body, by the formation of a kernel in the interior and a
-covering on the outer surface of the mass of plasma, there arose out of
-the original most simple cytods, or Monera, those four different species
-of plastids, or individuals, of the first order, from which, by
-differentiation and combination, all other organisms could afterwards
-develop themselves. (Compare vol. i. p. 347.)
-
-The question now forces itself upon us, Are all organic cytods and
-cells, and consequently also those "original cells" which we previously
-considered to be the primary parents of the few great main groups of the
-animal and vegetable kingdoms, descended from a single original form of
-Moneron, or were there several different organic primary forms, each
-traceable to a peculiar independent species of Moneron which originated
-by spontaneous generation? In other words, _Is the whole organic world
-of a common origin, or does it owe its origin to several acts of
-spontaneous generation?_ This fundamental question of genealogy seems at
-first sight to be of exceeding importance. But on a more accurate
-examination, we shall soon see that this is not the case, and that it is
-in reality a matter of very subordinate importance.
-
-Let us now pass on to examine and clearly limit our conception of an
-_organic tribe_. By _tribe_, or _phylum_, we understand all those
-organisms of whose blood relationship and descent from a common primary
-form there can be no doubt, or whose relationship, at least, is most
-probable from anatomical reasons, as well as from reasons founded on
-historical development. Our tribes, or phyla, according to this idea,
-essentially coincide with those few "great classes," or "main classes,"
-of which Darwin also thinks that each contains only organisms related by
-blood, and of which, both in the animal and in the vegetable kingdoms,
-he only assumes either four or five. In the animal kingdom these tribes
-would essentially coincide with those four, five, or six main divisions
-which zoologists, since Baer and Cuvier, have distinguished as "main
-forms, general plans, branches, or sub-kingdoms" of the animal kingdom.
-(Compare vol. i. p. 53.) Baer and Cuvier distinguished only four of them,
-namely:--1. The vertebrate animals (Vertebrata); 2. The articulated
-animals (Articulata); 3. The molluscous animals (Mollusca); and 4. The
-radiated animals (Radiata). At present six are generally distinguished,
-since the tribe of the articulated animals is divided into two tribes,
-those possessing articulated feet (Arthropoda), and the worms (Vermes);
-and in like manner the tribe of radiated animals is subdivided into the
-two tribes of the star animals (Echinodermata) and the animal-plants
-(Zoophyta). Within each of these six tribes, all the included animals,
-in spite of great variety in external form and inner structure,
-nevertheless possess such numerous and important characteristics in
-common, that there can be no doubt of their blood relationship. The same
-applies also to the six great main classes which modern botany
-distinguishes in the vegetable kingdom, namely:--1. Flowering plants
-(Phanerogamia); 2. Ferns (Filicinae); 3. Mosses (Muscinae); 4. Lichens
-(Lichenes); 5. Fungi (Fungi); and 6. Water-weeds (Algae). The last three
-groups, again, show such close relations to one another, that by the
-name of "Thallus plants" they may be contrasted with the three first
-main classes, and consequently the number of phyla, or main groups, of
-the vegetable kingdom may be reduced to the number of four. Mosses and
-ferns may likewise be comprised as "Prothallus plants" (Prothallophyta),
-and thereby the number of plant tribes reduced to three--Flowering
-plants, Prothallus plants, and Thallus plants.
-
-Very important facts in the anatomy and the history of development, both
-in the animal and vegetable kingdoms, support the supposition that even
-these few main classes or tribes are connected at their roots, that is,
-that the lowest and most ancient primary forms of all three are related
-by blood to one another. Nay, by a further examination we are obliged to
-go still a step further, and to agree with Darwin's supposition, that
-even the two pedigrees of the animal and vegetable kingdom are connected
-at their lowest roots, and that the lowest and most ancient animals and
-plants are derived from a single common primary creature. According to
-our view, this common primaeval organism can have been nothing but a
-Moneron which took its origin by spontaneous generation.
-
-In the mean time we shall at all events be acting cautiously if we avoid
-this last step, and assume true blood relationship only within each
-tribe, or phylum, where it has been undeniably and surely established by
-facts in comparative anatomy, ontogeny, and phylogeny. But we may here
-point to the fact that two different fundamental forms of genealogical
-hypothesis are possible, and that all the different investigations of
-the Theory of Descent in relation to the origin of organic groups of
-forms will, in future, tend more and more in one or the other of these
-directions. The unitary, or _monophyletic_, hypothesis of descent will
-endeavour to trace the first origin of all individual groups of
-organisms, as well as their totality, to a single common species of
-Moneron which originated by spontaneous generation (vol. i. p. 343). The
-multiple, or _polyphyletic_, hypothesis of descent, on the other hand,
-will assume that several different species of Monera have arisen by
-spontaneous generation, and that these gave rise to several different
-main classes (tribes, or phyla) (vol. i. p. 348). The apparently great
-contrast between these two hypotheses is in reality of very little
-importance. For both the monophyletic and the polyphyletic hypothesis of
-descent must necessarily go back to the Monera as the most ancient root
-of the one or of the many organic tribes. But as the whole body of a
-Moneron consists only of a simple, formless mass, without component
-particles, made up of a single albuminous combination of carbon, it
-follows that the differences of the different Monera can only be of a
-chemical nature, and can only consist in a different atomic composition
-of that mucous albuminous combination. But these subtle and complicated
-differences of mixture of the infinitely manifold combinations of
-albumen are not appreciable by the rude and imperfect means of human
-observation and are, consequently, at present of no further interest to
-the task we have in hand.
-
-The question of the monophyletic or polyphyletic origin will constantly
-recur within each individual tribe, where the origin of a smaller or of
-a larger group is discussed. In the vegetable kingdom, for example, some
-botanists will be inclined to derive all flowering plants from a single
-form of fern, while others will prefer the idea that several different
-groups of Phanerogama have sprung from several different groups of
-ferns. In like manner, in the animal kingdom, some zoologists will be
-more in favour of the supposition that all placental animals are derived
-from a single pouched animal; others will be more in favour of the
-opposite supposition, that several different groups of placental animals
-have proceeded from several different pouched animals. In regard to the
-human race itself, some will prefer to derive it from a single form of
-ape, while others will be more inclined to the idea that several
-different races of men have arisen, independently of one another, out of
-several different species of ape. Without here expressing our opinion in
-favour of either the one or the other conception, we must, nevertheless,
-remark that in general _the monophyletic hypothesis of descent deserves
-to be preferred to the polyphyletic hypothesis of descent_. In
-accordance with the chorological proposition of a single "centre of
-creation" or of a single primaeval home for most species (which has
-already been discussed), we may be permitted to assume that the original
-form of every larger or smaller natural group only originated _once_ in
-the course of time, and only in _one part_ of the earth. We may safely
-assume this simple original root, that is, the monophyletic origin, in
-the case of all the more highly developed groups of the animal and
-vegetable kingdoms. (Compare vol. i. p. 353.) But it is very possible
-that the more complete Theory of Descent of the future will involve the
-polyphyletic origin of very many of the low and imperfect groups of the
-two organic kingdoms.
-
-For these reasons I consider it best, in the mean time, to adopt the
-_monophyletic hypothesis of descent_ both for the animal and for the
-vegetable kingdom. Accordingly, the above-mentioned six tribes, or
-phyla, of the animal kingdom must be connected at their lowest root,
-and likewise the three or six main classes, or phyla, of the vegetable
-kingdom must be traced to a common and most ancient original form. How
-the connection of these tribes is to be conceived I shall explain in the
-succeeding chapters. But before proceeding to this, we must occupy
-ourselves with a very remarkable group of organisms, which cannot
-without artificial constraint be assigned either to the pedigree of the
-vegetable or to that of the animal kingdom. These interesting and
-important organisms are the _primary creatures_, or _Protista_.
-
-All organisms which we comprise under the name of Protista show in their
-external form, in their inner structure, and in all their vital
-phenomena, such a remarkable mixture of animal and vegetable properties,
-that they cannot with perfect justice be assigned either to the animal
-or to the vegetable kingdom; and for more than twenty years an endless
-and fruitless dispute has been carried on as to whether they are to be
-assigned to this or that kingdom. Most of Protista are so small that
-they can scarcely, if at all, be perceived with the naked eye. Hence the
-majority of them have only become known during the last fifty years,
-since by the help of the improved and general use of the microscope
-these minute organisms have been more frequently observed and more
-accurately examined. However, no sooner were they better known than
-endless disputes arose about their real nature and their position in the
-natural system of organisms. Many of these doubtful primary creatures
-botanists defined as animals, and zoologists as plants; neither of the
-two would own them. Others, again, were declared by botanists to be
-plants, and by zoologists to be animals; each claimed them. These
-contradictions are not altogether caused by our imperfect knowledge of
-the Protista, but in reality by their true nature. Indeed, most Protista
-present such a confused mixture of several animal and vegetable
-characteristics, that each investigator may arbitrarily assign them
-either to the animal or vegetable kingdom. Accordingly as he defines
-these two kingdoms, and as he looks upon this or that characteristic as
-determining the animal or vegetable nature, he will assign the
-individual classes of Protista in one case to the animal and in another
-to the vegetable kingdom. But this systematic difficulty has become an
-inextricable knot by the fact that all more recent investigations on the
-lowest organisms have completely effaced, or at least destroyed, the
-sharp boundary between the animal and vegetable kingdom which had
-hitherto existed, and to such a degree that its restoration is possible
-only by means of a completely artificial definition of the two kingdoms.
-But this definition could not be made so as to apply to many of the
-Protista.
-
-For this and other reasons it is, in the mean time, best to exclude the
-doubtful beings from the animal as well as from the vegetable kingdom,
-and to comprise them in a third organic kingdom standing midway between
-the two others. This intermediate kingdom I have established as the
-_Kingdom of the Primary Creatures_ (Protista), when discussing general
-anatomy in the first volume of my General Morphology, pp. 191-238. In my
-Monograph of the Monera,(15) I have recently treated of this kingdom,
-having somewhat changed its limits, and given it a more accurate
-definition. Of independent classes of the kingdom Protista, we may at
-present distinguish the following:--
-
-1. The still living Monera; 2. The Amoeboidea, or Protoplasts; 3. The
-Whip-swimmers, or Flagellata; 4. The Flimmer-balls, or Catallacta; 5.
-The Tram-weavers, or Labyrinthuleae; 6. The Flint-cells, or Diatomeae; 7.
-The Slime-moulds, or Myxomycetes; 8. The Ray-streamers, or Rhizopoda.
-
-The most important groups at present distinguishable in these eight
-classes of Protista are named in the systematic table on p. 51. Probably
-the number of these Protista will be considerably increased in future
-days by the progressive investigations of the ontogeny of the simplest
-forms of life, which have only lately been carried on with any great
-zeal. With most of the classes named we have become intimately
-acquainted only during the last ten years. The exceedingly interesting
-Monera and Labyrinthuleae, as also the Catallacta, were indeed discovered
-only a few years ago. It is probable also that very numerous groups of
-Protista have died out in earlier periods, without having left any
-fossil remains, owing to the very soft nature of their bodies. We might
-add to the Protista from the still living lowest groups of
-organisms--the Fungi; and in so doing should make a very large addition
-to its domain. Provisionally we shall leave them among plants, though
-many naturalists have separated them altogether from the vegetable
-kingdom.
-
-_The pedigree of the kingdom Protista_ is still enveloped in the
-greatest obscurity. The peculiar combination of animal and vegetable
-properties, the indifferent and uncertain character of their relations
-of forms and vital phenomena, together with a number of several very
-peculiar features which separate most of the subordinate classes sharply
-from the others, at present baffle every attempt distinctly to make out
-their blood relationships with one another, or with the lowest animals
-on the one hand, and with the lowest plants on the other hand. It is not
-improbable that the classes specified, and many other unknown classes of
-Protista, represent quite independent organic tribes, or phyla, each of
-which has independently developed from one, perhaps from various, Monera
-which have arisen by spontaneous generation. If we do not agree to this
-polyphyletic hypothesis of descent, and prefer the monophyletic
-hypothesis of the blood relationship of all organisms, we shall have to
-Look upon the different classes of protista as the lower small
-off-shoots of the root, springing from the same simple monera root, out
-of which arose the two mighty and many-branched pedigrees of the animal
-kingdom on the one hand, and of the vegetable kingdom on the other.
-(compare pp. 74, 75.) before i enter into this difficult question more
-accurately, it will be appropriate to premise something further as to
-the contents of the classes of protista given on the next page, and
-their general natural history.
-
-
-SYSTEMATIC SURVEY
-
-_Of the Larger and Smaller Groups of the Kingdom Protista._
-
-  ----------------+--------------------+------------------+-----------------
-   _Classes of    | _Systematic Name   | _Orders of       |  _A name of a
-   the Protista   |  of the Classes_.  | Families of the  |  Genus
-   Kingdom._      |                    | Classes._        |  as an example._
-  ----------------+--------------------+------------------+-----------------
-                                       { 1. Gymnomonera      Protogenes
-  1. MONERS             Monera         { 2. Lepomonera       Protomyxa
-
-                                       { 1. Gymnamoebae       Amoeba
-  2. PROTOPLASTS        Amoeboida      { 2. Leptamoebae       Arcella
-                                       { 3. Gregarinae        Monocystis
-
-                                       { 1. Nudiflagellata   Euglena
-  3. WHIP-SWIMMERS      Flagellata     { 2. Cilioflagellata  Peridinium
-
-  4. FLIMMER-BALLS      Catallacta       1. Catallacta       Magosphaera
-
-  5. TRAM-WEAVERS       Labyrinthuleae    1. Labyrinthuleae    Labyrinthula
-
-                                       { 1. Striata          Navicula
-  6. FLINT-CELLS        Diatomea       { 2. Vittata          Tabellaria
-                                       { 3. Areolata         Coscinodiscus
-
-                                       { 1. Physareae         AEthalium
-  7. SLIME-MOULDS       Myxomycetes    { 2. Stemoniteae       Stemonitis
-                                       { 3. Trichiaceae       Arcyria
-                                       { 4. Lycogaleae        Reticularia
-
-                    {   I. Acyttaria   { 1. Monothalamia     Gromia
-                    {                  { 2. Polythalamia     Nummulina
-  8. RAY-STREAMERS  {
-     OR RHIZOPODS.  {  II. Heliozoa      1. Heliozoa         Actinosphaerium
-     (Root-feet)    {
-                    {                  { 1. Monocyttaria     Cyrtidosphaera
-                    { III. Radiolaria  { 2. Polycyttaria     Collosphaera
-
-
-[Illustration: FIG. 8.--Protamoeba primitiva, a fresh-water Moneron,
-much enlarged. _A._ The entire Moneron with its form-changing processes.
-_B._ It begins to divide itself into two halves. _C._ The division of
-the two halves is completed, and each now represents an independent
-individual.]
-
-It will perhaps seem strange that I should here again begin with the
-remarkable _Monera_ as the first class of the Protista kingdom, as I of
-course look upon them as the most ancient primary forms of all organisms
-without exception. Still, what are we otherwise to do with the _still
-living Monera_? We know nothing of their palaeontological origin, we know
-nothing of any of their relations to lower animals or plants, and we
-know nothing of their possible capability of developing into higher
-organisms. The simple and homogeneous little lump of slime or mucus
-which constitutes their entire body (Fig. 8) is the most ancient and
-original form of animal as well as of vegetable plastids. Hence it would
-evidently be just as arbitrary and unreasonable to assign them to the
-animal as it would be to assign them to the vegetable kingdom. In any
-case we shall for the present be acting more cautiously and critically
-if we comprise the still living Monera--whose number and distribution is
-probably very great--as a special and independent class, contrasting
-them with the other classes of the kingdom Protista, as well as with the
-animal kingdom. Morphologically considered, the Monera--on account of
-the perfect homogeneity of the albuminous substance of their bodies, on
-account of their utter want of heterogeneous particles--are more closely
-connected with anorgana than with organisms, and evidently form the
-transition between the inorganic and organic world of bodies, as is
-necessitated by the hypothesis of spontaneous generation. I have
-described and given illustrations of the forms and vital phenomena of
-the still living Monera (Protamoeba, Protogenes, Protomyxa, etc.) in my
-Monograph of the Monera,(15) and have briefly mentioned the most
-important facts in the eighth chapter (vol. i. pp. 183-187). Therefore,
-only by way of a specimen, I here repeat the drawing of the fresh-water
-Protamoeba (Fig. 8). The history of the life of an orange-red _Protomyxa
-adrantiaca_, which I observed at Lanzerote, one of the Canary Islands,
-is given in Plate I. (see its explanation in the Appendix). Besides
-this, I here add a drawing of the form of Bathybius, that remarkable
-Moneron discovered by Huxley, which lives in the greatest depths of the
-sea in the shape of naked lumps of protoplasm and reticular mucus (vol.
-i. p. 344).
-
-[Illustration: FIG. 9.--Bathybius Haeckelii, the "creature of primaeval
-slime," from the greatest depths of the sea. The figure, which is
-greatly magnified, only shows that form of the Bathybius which consists
-of a naked network of protoplasm, without the discoliths and cyatholiths
-which are found in other forms of the same Moneron, and which perhaps
-may be considered as the products of its secretion.]
-
-The _Amoebae_ of the present day, and the organisms most closely
-connected with them, _Arcellidae_ and _Gregarinae_, which we here unite as
-a second class of Protista under the name of _Amoeboidea_ (Protoplasta),
-present no fewer genealogical difficulties than the Monera. These
-primary creatures are at present usually placed in the animal kingdom
-without its in reality being understood why. For simple naked
-cells--that is, shell-less plastids with a kernel--occur as well among
-real plants as real animals. The generative cells, for example, in many
-Algae (spores and eggs) exist for a longer or shorter time in water in
-the form of naked cells with a kernel, which cannot be distinguished at
-all from the naked eggs of many animals (for example, those of the
-Siphonophorous Medusae). (Compare the figure of a naked egg of a
-bladder-wrack in Chapter xvii. p. 90.) In reality every naked simple
-cell, whether it proceeds from an animal or vegetable body, cannot be
-distinguished from an independent Amoeba. For an Amoeba is nothing but a
-simple primary cell, a naked little lump of cell-matter, or plasma,
-containing a kernel. The contractility of this plasma, which the free
-Amoeba shows in stretching out and drawing in its changing processes, is
-a general vital property of the organic plasma of all animal as well as
-of all vegetable plastids. When a freely moving Amoeba, which
-perpetually changes its form, passes into a state of rest, it draws
-itself together into the form of a globule, and surrounds itself with a
-secreted membrane. It can then be as little distinguished from an animal
-egg as from a simple globular vegetable cell (Fig. 10 _A_).
-
-[Illustration: FIG. 10.--Amoeba sphaerococcus, greatly magnified. A
-fresh-water Amoeba without a contractile vacuole. _A._ The enclosed
-Amoeba in the state of a globular lump of plasma (_c_) enclosing a
-kernel and a kernel-speck (_a_). The simple cell is surrounded by a
-cyst, or cell membrane (_d_). _B._ The free Amoeba, which has burst and
-left the cyst, or cell-membrane. _C._ It begins to divide by its kernel
-parting into two kernels, and the cell-substance between the two
-contracting. _D._ The division is completed, and the cell-substance has
-entirely separated into two bodies. (_Da_ and _Db_).]
-
-Naked cells, with kernels, like those represented in Fig. 10 _B_, which
-are continuously changing, stretching out and drawing in formless,
-finger-like processes, and which are on this account called amoeboid,
-are found frequently and widely dispersed in fresh water and in the sea;
-nay, are even found creeping on land. They take their food in the same
-way as was previously described in the case of the Protamoeba (vol. i.
-p. 186). Their propagation by division can sometimes be observed. (Fig.
-10 _C_, _D_.) I have described the processes in an earlier chapter (vol.
-i. p. 187). Many of these formless Amoebae have lately been recognized as
-the early stages of development of other Protista (especially the
-Myxomycetae), or as the freed cells of lower animals and plants. The
-colourless blood-cells of animals, for example, those of human blood,
-cannot be distinguished from Amoebae. They, like the latter, can receive
-solid corpuscles into their interior, as I was the first to show by
-feeding them with finely divided colouring matters (Gen. Morph. i. 271).
-However, other Amoebae (like the one given in Fig. 10) seem to be
-independent "good species," since they propagate themselves unchanged
-throughout many generations. Besides the real, or _naked_, Amoebae
-(Gymnamoebae), we also find widely diffused in fresh water _case-bearing_
-Amoebae (Lepamoebae), whose naked plasma body is _partially_ protected by
-a more or less solid shell (Arcella), sometimes even by a case
-(Difflugia) composed of small stones. Lastly, we frequently find in the
-body of many lower animals parasitic Amoebae (Gregarinae), which, adapting
-themselves to a parasitic life, have surrounded their plasma-body with a
-delicate closed membrane.
-
-The simple naked Amoebae are, next to the Monera, the most important of
-all organisms to the whole science of biology, and especially to general
-genealogy. For it is evident that the Amoebae originally arose out of
-simple Monera (Protamoebae), by the important process of segregation
-taking place in their homogeneous viscid body--the differentiation of an
-inner kernel from the surrounding plasma. By this means the great
-progress from a simple cytod (without kernel) into a real cell (with
-kernel) was accomplished (compare Fig. 8 _A_ and Fig. 10 _B_). As some
-of these cells at an early stage encased themselves by secreting a
-hardened membrane, they formed the first vegetable cells, while others,
-remaining naked, developed into the first aggregates of animal cells.
-The presence or absence of an encircling hard membrane forms the most
-important, although by no means the entire, difference of form between
-animal and vegetable cells. As vegetable cells even at an early stage
-enclose themselves within their hard, thick, and solid cellular shell,
-like that of the Amoebae in a state of rest (Fig. 10 _A_), they remain
-more independent and less accessible to the influences of the outer
-world than are the soft animal cells, which are in most cases naked, or
-merely covered by a thin pliable membrane. But in consequence of this
-the vegetable cells cannot combine, as do the animal cells, for the
-construction of higher and composite fibrous tracts, for example, the
-nervous and muscular tissues. It is probable that, in the case of the
-most ancient single-celled organisms, there must have developed at an
-early stage the very important difference in the animal and vegetable
-mode of receiving food. The most ancient single-celled animals, being
-naked cells, could admit solid particles into the interior of their soft
-bodies, as do the Amoebae (Fig. 10 _B_) and the colourless blood-cells;
-whereas the most ancient single-celled plants encased by their membranes
-were no longer able to do this, and could admit through it only fluid
-nutrition (by means of diffusion).
-
-[Illustration: FIG. 11.--A single Whip-swimmer (Euglena striata),
-greatly magnified. Above a thread-like lashing whip is visible; in the
-centre the round cellular kernel, with its kernel speck.]
-
-The _Whip-swimmers_ (Flagellata), which we consider as a third class of
-the kingdom Protista, are of no less doubtful nature than the Amoebae.
-They often show as close and important relations to the vegetable as to
-the animal kingdom. Some Flagellata at an early stage, when freely
-moving about, cannot be distinguished from real plants, especially from
-the spores of many Algae; whereas others are directly allied to real
-animals, namely, to the fringed Infusoria (Ciliata). The Flagellata are
-simple cells which live in fresh or salt water, either singly or united
-in colonies. The characteristic part of their body is a very movable
-simple or compound whip-like appendage (whip, or flagellum) by means of
-which they actively swim about in the water. This class is divided into
-two orders. Among the fringed whip-swimmers (Cilioflagellata) there
-exists, in addition to the long whip, a short fringe of vibrating hairs,
-which is wanting in the unfringed whip-swimmers (Nudoflagellata). To the
-former belong the flint-shelled yellow Peridinia, which are largely
-active in causing the phosphorescence of the sea; to the latter belong
-the green Euglenae, immense masses of which frequently make our ponds in
-spring quite green.
-
-[Illustration: FIG. 12.--The Norwegian Flimmer-ball (Magosphaera planula)
-swimming by means of its vibratile fringes, as seen from the surface.]
-
-A very remarkable new form of Protista, which I have named
-_Flimmer-ball_ (Magosphaera), I discovered only three years ago (in
-September, 1869), on the Norwegian coast (Fig. 12), and have more
-accurately described in my Biological Studies(15) (p. 137, Plate V.).
-Off the island of Gis-oe, near Bergen, I found swimming about, on the
-surface of the sea, extremely neat little balls composed of a number
-(between thirty and forty) of fringed pear-shaped cells, the pointed
-ends of which were united in the centre like radii. After a time the
-ball dissolved. The individual cells swarmed about independently in the
-water like fringed Infusoria, or Ciliata. These afterwards sank to the
-bottom, drew their fringes into their bodies, and gradually changed into
-the form of creeping Amoebae (like Fig 10 _B_). These last afterwards
-encased themselves (as in Fig. 10 _A_), and then divided by repeated
-halvings into a large number of cells (exactly as in the case of the
-cleavage of the egg, Fig. 6, vol. i. p. 299). The cells became covered
-with vibratile hairs, broke through the case enclosing them, and now
-again swam about in the shape of a fringed ball (Fig. 12). This
-wonderful organism, which sometimes appears like a simple Amoeba,
-sometimes as a single fringed cell, sometimes as a many-celled fringed
-ball, can evidently be classed with none of the other Protista, and must
-be considered as the representative of a new independent group. As this
-group stands midway between several Protista, and links them together,
-it may bear the name of _Mediator_, or _Catallacta_.
-
-[Illustration: FIG. 13.--Labyrinthula macrocystis (much enlarged). Below
-is a large group of accumulated cells, one of which, on the left, is
-separating itself; above are two single cells which are gliding along
-the threads of the retiform labyrinth which form their "tramways."]
-
-The Protista of the fifth class, the _Tram-weavers_, or _Labyrinthuleae_,
-are of a no less puzzling nature; they were lately discovered by
-Cienkowski on piles in sea water (Fig. 13). They are spindle-shaped
-cells, mostly of a yellow-ochre colour, which are sometimes united into
-a dense mass, sometimes move about in a very peculiar way. They form, in
-a manner not yet explained, a retiform frame of entangled threads
-(compared to a labyrinth), and on the dense filamentous "tramways" of
-this frame they glide about. From the shape of the cells of the
-Labyrinthuleae we might consider them as the simplest plants, from their
-motion as the simplest animals, but in reality they are neither animals
-nor plants.
-
-[Illustration: FIG. 14.--Navicula hippocampus (greatly magnified). In
-the middle of the cell the cell-kernel (nucleus) is visible, together
-with its kernel speck (nucleolus).]
-
-The _Flint-cells_ (Diatomeae), a sixth class of Protista, are perhaps the
-most closely related to the Labyrinthuleae. These primary
-creatures--which at present are generally considered as plants, although
-some celebrated naturalists still look upon them as animals--inhabit the
-sea and fresh waters in immense masses, and offer an endless variety of
-the most elegant forms. They are mostly small microscopic cells, which
-either live singly (Fig. 14), or united in great numbers, and occur
-either attached to objects, or glide and creep about in a peculiar
-manner. Their soft cell-substance, which is of a characteristic brownish
-yellow colour, is always enclosed by a solid and hard flinty shell,
-possessing the neatest and most varied forms. This flinty covering is
-open to the exterior only by one or two slits, through which the
-enclosed soft plasma-body communicates with the outer world. The flinty
-cases are found petrified in masses, and many rocks--for example, the
-Tripoli slate polish, the Swedish mountain meal, etc.,--are in a great
-measure composed of them.
-
-A seventh class of Protista is formed by the remarkable _Slime-moulds_
-(Myxomycetes). They were formerly universally considered as plants, as
-real Fungi, until ten years ago the botanist De Bary, by discovering
-their ontogeny, proved them to be quite distinct from Fungi, and rather
-to be akin to the lower animals. The mature body is a roundish bladder,
-often several inches in size, filled with fine spore-dust and soft
-flakes (Fig. 15), as in the case of the well-known puff-balls
-(Gastromycetes). However, the characteristic cellular threads, or hyphae,
-of a real fungus do not arise from the germinal corpuscles, or spores,
-of the Myxomycetes, but merely naked masses of plasma, or cells, which
-at first swim about in the form of Flagellata (Fig. 11), afterwards
-creep about like the Amoebae (Fig. 10 _B_), and finally combine with
-others of the same kind to form large masses of "slime," or "plasmodia."
-Out of these, again, there arises, by-and-by, the bladder-shaped
-fruit-body. Many of my readers probably know one of these plasmodia, the
-AEthalium septicum, which in summer forms a beautiful yellow mass of soft
-mucus, often several feet in breadth, known by the name of "tan
-flowers," and penetrates tan-heaps and tan-beds. At an early stage these
-slimy, freely-creeping Myxomycetes, which live for the most part in damp
-forests, upon decaying vegetable substances, bark of trees, etc., are
-with equal justice or injustice declared by zoologists to be animals,
-while in the mature, bladder-shaped condition of fructification they are
-by botanists defined as plants.
-
-[Illustration: FIG. 15.--A stalked fruit-body (spore-bladder, filled
-with spores) of one of the Myxomycetes (Physarum albipes) not much
-enlarged.]
-
-The nature of the _Ray-streamers_ (Rhizopoda), the eighth class of the
-kingdom Protista, is equally obscure. These remarkable organisms have
-peopled the sea from the most ancient times of the organic history of
-the earth, in an immense variety of forms, sometimes creeping at the
-bottom of the sea, sometimes swimming on the surface. Only very few live
-in fresh water (Gromia, Actinosphaerium). Most of them possess solid
-calcareous or flinty shells of an extremely beautiful construction,
-which can be perfectly preserved in a fossil state. They have frequently
-accumulated in such huge numbers as to form mountain masses, although
-the single individuals are very small, and often scarcely visible, or
-completely invisible to the naked eye. A very few attain the diameter
-of a few lines, or even as much as a couple of inches. The name which
-the class bears is given because thousands of exceedingly fine threads
-of protoplasm radiate from the entire surface of their naked slimy body;
-these rays are quasi-feet, or pseudopodia, which branch off like roots
-(whence the term Rhizopoda, signifying root-footed), unite like nets,
-and are observed continually to change form, as in the case of the
-simpler plasmic feet of the Amoeboidea, or Protoplasts. These
-ever-changing little pseudo-feet serve both for locomotion and for
-taking food.
-
-The class of the Rhizopoda is divided into three different legions, viz.
-the chamber-shells, or Acyttaria, the sun-animalcules, or Heliozoa, and
-the basket-shells, or Radiolaria. The _Chamber-shells_ (Acyttaria)
-constitute the first and lowest of these three legions; for the whole of
-their soft body consists merely of simple mucous or slimy cell-matter,
-or protoplasm, which has not differentiated into cells. However, in
-spite of this most primitive nature of body, most of the Acyttaria
-secrete a solid shell composed of calcareous earth, which presents a
-great variety of exquisite forms. In the more ancient and more simple
-Acyttaria this shell is a simple chamber, bell-shaped, tubular, or like
-the shell of a snail, from the mouth of which a bundle of plasmic
-threads issues. In contrast to these _single-chambered forms_
-(Monothalamia), the _many-chambered forms_ (Polythalamia)--to which the
-great majority of the Acyttaria belong--possess a house, which is
-composed in an artistic manner of numerous chambers. These chambers
-sometimes lie in a row one behind the other, sometimes in concentric
-circles or spirals, in the form of a ring round a central point, and
-then frequently one above another in many tiers, like the boxes of an
-amphitheatre. This formation, for example, is found in the nummulites,
-whose calcareous shells, of the size of a lentil, have accumulated to
-the number of millions, and form whole mountains on the shores of the
-Mediterranean. The stones of which some of the Egyptian pyramids are
-built consist of such nummulitic limestone. In most cases the chambers
-of the shells of the Polythalamia are wound round one another in a
-spiral line. The chambers are connected with one another by passages and
-doors, like rooms of a large palace, and are generally open towards the
-outside by numerous little windows, out of which the plasmic body can
-stream or strain forth its little pseudo-feet, or rays of slime, which
-are always changing form. But in spite of the exceedingly complicated
-and elegant structure of this calcareous labyrinth, in spite of the
-endless variety in the structure and the decoration of its numerous
-chambers, and in spite of the regularity and elegance of their
-execution, the whole of this artistic palace is found to be the secreted
-product of a perfectly formless, slimy mass, devoid of any component
-parts! Verily, if the whole of the recent anatomy of animal and
-vegetable textures did not support our theory of plastids, if all its
-important results did not unanimously corroborate the fact that the
-whole miracle of vital phenomena and vital forms is traceable to the
-active agency of the formless albuminous combinations of protoplasm, the
-Polythalamia alone would secure the triumph of that theory. For we may
-here at any moment, by means of the microscope, point out the wonderful
-fact, first established by Dujardin and Max Schulze, that the formless
-mucus of the soft plasma-body, this true "matter of life," is able to
-secrete the neatest, most regular, and most complicated structures. This
-secretive skill is simply a result of _inherited adaptation_, and by it
-we learn to understand how this same "primaeval slime"--this same
-protoplasm--can produce in the bodies of animals and plants the most
-different and most complicated cellular forms.
-
-It is, moreover, a matter of special interest that the most ancient
-organism, the remains of which are found in a petrified condition,
-belongs to the Polythalamia. This organism is the "Canadian Life's-dawn"
-(_Eozoon canadense_), which has already been mentioned, and which was
-found a few years ago in the Ottawa formation (in the deepest strata of
-the Laurentian system), on the Ottawa river in Canada. If we expected to
-find organic remains at all in these most ancient deposits of the
-primordial period, we should certainly look for such of the most simple
-Protista as are covered with a solid shell, and in the organization of
-which the difference between animal and plant is as yet not indicated.
-
-We know of but few species of the _Sun-animalcules_ (Heliozoa), the
-second class of the Rhizopoda. One species is very frequently found in
-our fresh waters. It was observed even in the last century by a
-clergyman in Dantzig, Eichhorn by name, and it has been called after
-him, Actinosphaerium Eichhornii. To the naked eye it appears as a
-gelatinous grey globule of mucus, about the size of a pin's head.
-Looking at it through the microscope, we see hundreds or thousands of
-fine mucous threads radiating from the central plasma body, and perceive
-that the inner layer of its cell-substance is different from the outer
-layer, which forms a bladder-like membrane. In consequence of its
-structure, this, the little sun-animalcule, although wanting a shell,
-really rises above the structureless Acyttaria, and forms the transition
-from these to the Radiolaria. The genus Cystophrys is of a nature akin
-to it.
-
-The _Basket-shells_ (Radiolaria) form the third and last class of the
-Rhizopoda. Their lower forms are closely allied to the Heliozoa and
-Acyttaria, whereas their higher forms rise far above them. They are
-essentially distinguished from both by the fact that the central part of
-their body is composed of many cells, and surrounded by a solid
-membrane. This closed "central capsule," generally of a globular shape,
-is covered by a mucous layer of plasma, out of which there radiate on
-all sides thousands of exceedingly fine threads, the branching and
-confluent so-called pseudopodia. Between these are scattered numerous
-yellow cells of unknown function, containing grains of starch. Most
-Radiolaria are characterized by a highly developed skeleton, which
-consists of flint, and displays a wonderful richness of the neatest and
-most curious forms. Sometimes this flinty skeleton forms a simple
-trellice-work ball (Fig. 16 _s_), sometimes a marvellous system of
-several concentric trelliced balls, encased in one another, and
-connected by radial staves. In most cases delicate spikes, which are
-frequently branched like a tree, radiate from the surface of the balls.
-In other cases the whole skeleton consists of only one flinty star, and
-is then generally composed of twenty staves, distributed according to
-definite mathematical laws, and united in a common central point. The
-skeletons of other Radiolaria again form symmetrical many-chambered
-structures, as in the case of the Polythalamia. Perhaps no other group
-of organisms develop in the formation of their skeletons such an amount
-of various fundamental forms, such geometrical regularity, and such
-elegant architecture. Most of the forms as yet discovered, I have given
-in the atlas accompanying my Monograph of the Radiolaria.(23) Here I
-shall only give as an example the picture of one of the simplest forms,
-the _Cyrtidosphaera echinoides_ of Nice. The skeleton in this case
-consists only of a simple trelliced ball (_s_), with short radial spikes
-(_a_), which loosely surround the central capsule (_c_). Out of the
-mucous covering, enclosing the latter, radiate a great number of
-delicate little pseudopodia (_p_), which are partly drawn back
-underneath the shell, and fused into a lumpy mass of mucus. Between
-these are scattered a number of yellow cells (_l_).
-
-[Illustration: FIG. 16.--Cyrtidosphaera echinoides, 400 times enlarged.
-_c._ Globular central capsule. _s._ Basket-work of the perforated flinty
-shell. _a._ Radial spikes, which radiate from the latter. _p._ The
-pseudo-feet radiating from the mucous covering surrounding the central
-capsule. _l._ Yellow globular cells, scattered between the latter,
-containing grains of starch.]
-
-Most Acyttaria live only at the bottom of the sea, on stones and
-seaweeds, or creep about in sand and mud by means of their pseudopodia,
-but most Radiolaria swim on the surface of the sea by means of long
-pseudopodia extending in all directions. They live together there in
-immense numbers, but are mostly so small that they have been almost
-completely overlooked, and have only become accurately known during the
-last fourteen years. Certain Radiolaria living in communities
-(Polycyttaria) form gelatinous lumps of some lines in diameter. On the
-other hand, most of those living isolated (Monocyttaria) are invisible
-to the naked eye; but still their petrified shells are found accumulated
-in such masses that in many places they form entire mountains; for
-example, the Nicobar Islands in the Indian Archipelago, and the Island
-of Barbadoes in the Antilles.
-
-As most readers are probably but little acquainted with the eight
-classes of the Protista just mentioned, I shall now add some further
-general observations on their natural history. The great majority of all
-Protista live in the sea, some swimming freely on the surface, some
-creeping at the bottom, and others attached to stones, shells, plants,
-etc. Many species of Protista also live in fresh water, but only a very
-small number on dry land (for example, Myxomycetes and some
-Protoplasta). Most of them can be seen only through the microscope,
-except when millions of individuals are found accumulated. Only a few of
-them attain a diameter of some lines, or as much as an inch. What they
-lack in size of body they make up for by producing astonishing numbers
-of individuals, and they very considerably influence in this way the
-economy of nature. The imperishable remains of dead Protista, for
-instance, the flinty shells of the Diatomeae and Radiolaria and the
-calcareous shells of the Acyttaria, often form large rock masses.
-
-In regard to their _vital phenomena_, especially those of nutrition and
-propagation, some Protista are more allied to plants, others more to
-animals. Both in their mode of taking food and in the chemical changes
-of their living substance, they sometimes more resemble the lower
-animals, at others the lower plants. _Free locomotion_ is possessed by
-many Protista, while others are without it; but this does not constitute
-a characteristic distinction, as we know of undoubted animals which
-entirely lack free locomotion, and of genuine plants which possess it.
-All Protista have a _soul_--that is to say, are "animate"--as well as
-all animals and all plants. The soul's activity in the Protista
-manifests itself in their _irritability_, that is, in the movements and
-other changes which take place in consequence of mechanical, electrical,
-and chemical irritation of their contractile protoplasm. Consciousness
-and the capability of will and thought are probably wanting in all
-Protista. However, the same qualities are in the same degree also
-wanting in many of the lower animals, whereas many of the higher animals
-in these respects are scarcely inferior to the lower races of human
-beings. In the Protista, as in all other organisms, the activities of
-the soul are traceable to molecular motions in the protoplasm.
-
-The most important _physiological characteristic_ of the kingdom
-Protista lies in the exclusively _non-sexual propagation_ of all the
-organisms belonging to it. The higher animals and plants multiply almost
-exclusively in a sexual manner. The lower animals and plants multiply
-also, in many cases, in a non-sexual manner, by division, the formation
-of buds, the formation of germs, etc. But sexual propagation almost
-always exists by the side of it, and often regularly alternates with it
-in succeeding generations (Metagenesis, vol. i. p. 206). All Protista,
-on the other hand, propagate themselves exclusively in a non-sexual
-manner, and in fact, the distinction of the two sexes among them has not
-been effected--there are neither male nor female Protista.
-
-The Protista in regard to their vital phenomena stand midway between
-animals and plants, that is to say, between their lowest forms; and the
-same must be said in regard to the _chemical composition_ of their
-bodies. One of the most important distinctions between the chemical
-composition of animal and vegetable bodies consists in the
-characteristic formation of the skeleton. The skeleton, or the solid
-scaffolding of the body in most genuine plants, consists of a substance
-called cellulose, devoid of nitrogen, but secreted by the nitrogenous
-cell-substance, or protoplasm. In most genuine animals, on the other
-hand, the skeleton generally consists either of nitrogenous combinations
-(chitin, etc.) or of calcareous earth. In this respect some Protista are
-more like plants, others more like animals. In many of them the skeleton
-is principally or entirely formed of calcareous earth, which is met with
-both in animal and vegetable bodies. But the active vital substance in
-all cases is the mucous protoplasm.
-
-In regard to the _form_ of the Protista, it is to be remarked that the
-_individuality_ of their body almost always remains at an extremely low
-stage of development. Very many Protista remain for life simple plastids
-or individuals of the first order. Others, indeed, form colonies or
-republics of plastids by the union of several individuals. But even
-these higher individuals of the second order, formed by the combination
-of simple plastids, for the most part remain at a very low stage of
-development. The members of such communities among the Protista remain
-very similar one to another, and never, or only in a slight degree,
-commence a division of labour, and are consequently as little able to
-render their community fit for higher functions as are, for example, the
-savages of Australia. The community of the plastids remains in most
-cases very loose, and each single plastid retains in a great measure its
-own individual independence.
-
-A second structural characteristic, which next to their low stage of
-individuality especially distinguishes the Protista, is the low stage of
-development of their stereometrical fundamental forms. As I have shown
-in my theory of fundamental forms (in the fourth book of the General
-Morphology), a definite geometrical fundamental form can be pointed out
-in most organisms, both in the general form of the body and in the form
-of the individual parts. This ideal fundamental form, or type, which is
-determined by the number, position, combination, and differentiation of
-the component parts, stands in just the same relation to the _real_
-organic form as the ideal geometrical fundamental form of crystals does
-to their imperfect _real_ form. In most bodies and parts of the bodies
-of animals and plants this fundamental form is a pyramid. It is a
-regular pyramid in the so-called "regular radiate" forms, and an
-irregular pyramid in the more highly differentiated, so-called
-"bilaterally symmetrical" forms. (Compare the plates in the first volume
-of my General Morphology, pp. 556-558.) Among the Protista this
-pyramidal type, which prevails in the animal and vegetable kingdom, is
-on the whole rare, and instead of it we have either quite irregular
-(amorphous) or more simple, regular geometrical types; especially
-frequent are the sphere, the cylinder, the ellipsoid, the spheroid, the
-double cone, the cone, the regular polygon (tetrahedron, hexahedron,
-octahedron, dodecahedron, icosahedron), etc. All the fundamental forms
-of the pro-morphological system, which are of a low rank in that system,
-prevail in the Protista. However, in many Protista there occur also the
-higher, regular, and bilateral types, fundamental forms which
-predominate in the animal and vegetable kingdoms. In this respect some
-of the Protista are frequently more closely allied to animals (as the
-Acyttaria), others more so to plants (as the Radiolaria).
-
-With regard to the _palaeontological development of the kingdom
-Protista_, we may form various, but necessarily very unsafe,
-genealogical hypotheses. Perhaps the individual classes of the kingdom
-are independent tribes, or phyla, which have developed independently of
-one another and independently of the animal and the vegetable kingdoms.
-Even if we adopt the monophyletic hypothesis of descent, and maintain a
-common origin from a single form of Moneron for all organisms, without
-exception, which ever have lived and still live upon the earth, even in
-this case the connection of the neutral Protista on the one hand with
-the vegetable kingdom, and on the other hand with the animal kingdom,
-must be considered as very vague. We must regard them (compare p. 74) as
-lower off-shoots which have developed directly out of the root of the
-great double-branched organic pedigree, or perhaps out of the lowest
-tribe of Protista, which may be supposed to have shot up midway between
-the two diverging high and vigorous trunks of the animal and vegetable
-kingdoms. The individual classes of the Protista, whether they are more
-closely connected at their roots in groups, or only form a loose bunch
-of root offsets, must in this case be regarded as having nothing to do
-either with the diverging groups of organisms belonging to the animal
-kingdom on the right, or to the vegetable kingdom on the left. They must
-be supposed to have retained the original simple character of the common
-primaeval living thing more than have genuine animals and genuine plants.
-
-But if we adopt the polyphyletic hypothesis of descent, we have to
-imagine a number of organic tribes, or phyla, which all shoot up by
-spontaneous generation out of the same ground, by the side of and
-independent of one another. (Compare p. 75.) In that case numbers of
-different Monera must have arisen by spontaneous generation whose
-differences would depend only upon slight, to us imperceptible,
-differences in their chemical composition, and consequently upon
-differences in their capability of development. A small number of Monera
-would then have given origin to the animal kingdom, and, again, a small
-number would have produced the vegetable kingdom. Between these two
-groups, however, there would have developed, independently of them, a
-large number of independent tribes, which have remained at a lower stage
-of organization, and which have neither developed into genuine plants
-nor into genuine animals.
-
-A safe means of deciding between the monophyletic and polyphyletic
-hypotheses is as yet quite impossible, considering the imperfect state
-of our phylogenetic knowledge. The different groups of Protista, and
-those lowest forms of the animal kingdom and of the vegetable kingdom
-which are scarcely distinguishable from the Protista, show such a close
-connection with one another and such a confused mixture of
-characteristics, that at present any systematic division and arrangement
-of the groups of forms seem more or less artificial and forced. Hence
-the attempt here offered must be regarded as entirely provisional. But
-the more deeply we penetrate into the genealogical secrets of this
-obscure domain of inquiry, the more probable appears the idea that the
-vegetable kingdom and the animal kingdom are each of independent origin,
-and that midway between these two great pedigrees a number of other
-independent small groups of organisms have arisen by repeated acts of
-spontaneous generation, which on account of their indifferent neutral
-character, and in consequence of their mixture of animal and vegetable
-properties, may lay claim to the designation of independent Protista.
-
-
-         II.                                             III.
-
-  =Vegetable Kingdom=                             =Animal Kingdom=
-        Plantae                                        _Animalia_
-  /--------^----------\  /-------------------------------^------------\
-   Flowering Plants                               Vertebrate Animals
-   _Phanerogamia_                                   _Vertebrata_
-         |                                         \-----v-------/
-         |                                               |
-         |                                               |
-         |                           Articulated Animals |
-         |                              _Arthropoda_     |
-         |                              \-----v------/   |
-         |                                    |          |
-         |                                    |          |
-         |                  Star-fishes       |          |  Molluscous Animals
-       Ferns              _Echinoderma_       |          |    _Mollusca_
-    _Filicinae_            \-----v------/      |          |  \-----v------/
-         |                      |             |          |        |
-         |                      |             |          |        |
-         |                      |             |          |        |
-         |                      |             |          |        |
-      Mosses                   \-------------------v---------------/
-   _Muscinae_        Lichens                       Worms
-         |         _Lichenes_                    _Vermes_
-         |             |                             |
-         |             |                             |
-         |             |               Animal-trees  |
-         |             |              _Zoophytes_    |
-        ----           Fungi                 |         |
-      _Algae_        _Fungi_                |         |
-         |             |                   |         |
-         |             |                   |         |
-         \-------v-----/                   \-----v---/
-                            =Neutral=
-  =Primaeval Plants=   =Primaeval Creatures=  =Primaeval Animals=
-      Protophyta          Protista            Protozoa
-     \-----v------/      \-----v------/     \-----v------/
-
-          |||             |||||||||||           |||||
-          |||             |||||||||||           |||||
-          |||             |||||||||||           |||||
-     Vegetable Monera     Neutral Monera      Animal Monera
-           |                 |||||                |
-           |                 |||||                |
-           |                 |||||                |
-          \--------------------------v------------/
-
-                                     |
-                                     |
-                            =Archigonic Monera=
-
-  (Pieces of Protoplasm which have originated by Spontaneous Generation)
-
-             ----------------------------------------------------------------
-
-
-  POLYPHYLETIC PEDIGREE.
-
-         II.                                       I.                                III.
-
-    =Vegetable=                               =Protista=                          =Animal=
-     =Kingdom=                                =Kingdom=                           =Kingdom=
-     Vegetabilia                              Protista                            Animalia
-   \------v------/                                |                              \-----v----/
-          |                                       |                                    |
-          |                                       |                                    |
-          |   /-----------------------------------^--------------------------------\   |
-          |    Slime-moulds,                                                           |
-          |        or                                                                  |
-          |    Mucous Fungi                                   Ray-streamers            |
-          |    _Myxomycetes_                                   _Rhizopoda_             |
-          |   \-----v------/                                 \-----v------/            |
-          |         |                                              |                   |
-          |         |   Flint-cells                                |   Flimmer-balls   |
-          |         |    _Diatomae_                                 |     _Catallacta_  |
-          |         | \-----v------/                               |    \-----v------/ |
-          |         |       |                                      |          |        |
-          |         |       |                      Whip-swimmers   |          |        |
-          |         |       |                       _Flagellata_   |          |        |
-          |         |       |                      \-----v------/  |          |        |
-          |         |       |                            |         |          |        |
-          |         |       |    Tram-weavers            |         |          |        |
-          |         |       |   _Labyrinthulea_          |         |          |        |
-          |         |       |    \-----v------/          |         |          |        |
-          |         |       |          |                 |         |          |        |
-          |         |       |          |     Amoebae,     |         |          |    =Primaeval=
-  =Primaeval Plants= |       |          |       or        |         |          |    =Animals=
-       Protophyta   |       |          |   Protoplasta   |         |          |     Protozoa
-   \------v------/  |       |          | \-----v------/  |         |          |  \-----v------/
-         |||        |       |          |     |||||       |         |          |     |||||||
-         |||        |       |          |     |||||       |         |          |     |||||||
-         |||        |       |          |     |||||       |         |          |     |||||||
-         |||        |       |          |     |||||       |         |          |     |||||||
-     =Vegetable=    |       |          |   =Neutral=     |         |          |     =Animal=
-       =Monera=     |       |          |   =Monera=      |         |          |     =Monera=
-          |         |       |          |       |         |     T   |  T T     |  T     |
-     T    |         |   T   |          |  T    |         |   T |   |  | | T   |  |T    |    T
-     |T   |   T     |  T|   |    T     |  |T   |  T      |   | |   |  |T| |   |  ||T   |  T |T
-     ||T  |   |T    |  ||   |    |     |  ||   |  |T     |   |T|   |  |||T|   |  |||T  |  | ||
-    T|||T |  T||T   |  ||T  |   T|T    |  ||T  |  ||T    |   |||   |  |||||   |  ||||  |  |T||T
-    ||||| |  ||||   |  |||  |   |||    |  |||  |  |||    |   |||   |  |||||   |  ||||  |  |||||
-    ||||| |  ||||   |  |||  |   |||    |  |||  |  |||    |   |||   |  |||||   |  ||||  |  |||||
-    -------------------------------------------------------------------------------------------
-
-  N.B.--The lines marked with a T indicate extinct tribes of Protista,
-  which have arisen independently by repeated acts of Spontaneous Generation.
-
-
-Thus, if we assume one entirely independent trunk for the vegetable
-kingdom, and a second for the animal kingdom, we may set up a number of
-independent stems of Protista, each of which has developed, quite
-independently of other stems and trunks, from a special archigonic form
-of Monera. In order to make this relation more clear, we may imagine the
-whole world of organisms as an immense meadow which is partially
-withered, and upon which two many-branched and mighty trees are
-standing, likewise partially withered. The two great trees represent the
-animal and vegetable kingdoms, their fresh and still green branches the
-living animals and plants; the dead branches with withered leaves
-represent the extinct groups. The withered grass of the meadow
-corresponds to the numerous extinct tribes, and the few stalks, still
-green, to the still living phyla of the kingdom Protista. But the common
-soil of the meadow, from which all have sprung up, is primaeval by
-protoplasm.
-
-
-
-
-CHAPTER XVII.
-
-PEDIGREE AND HISTORY OF THE VEGETABLE KINGDOM.
-
-
-  The Natural System of the Vegetable Kingdom.--Division of the
-  Vegetable Kingdom into Six Branches and Eighteen Classes.--The
-  Flowerless Plants (Cryptogamia).--Sub-kingdom of the Thallus
-  Plants.--The Tangles, or Algae (Primary Algae, Green Algae, Brown
-  Algae, Red Algae).--The Thread-plants, or Inophytes (Lichens and
-  Fungi).--Sub-kingdom of the Prothallus Plants.--The Mosses, or
-  Muscinae (Water-mosses, Liverworts, Leaf-mosses,
-  Bog-mosses).--The Ferns, or Filicinae (Leaf-ferns, Bamboo-ferns,
-  Water-ferns, Scale-ferns).--Sub-kingdom of Flowering Plants
-  (Phanerogamia).--The Gymnosperms, or Plants with Naked Seeds
-  (Palm-ferns = Cycadeae; Pines = Coniferae).--The Angiosperms, or
-  Plants with Enclosed Seeds.--Monocotylae.--Dicotylae.--Cup-blossoms
-  (Apetalae).--Star-blossoms (Diapetalae).--Bell-blossoms
-  (Gamopetalae).
-
-
-Every attempt that we make to gain a knowledge of the pedigree of any
-small or large group of organisms related by blood must, in the first
-instance, start with the evidence afforded by the existing "_natural
-system_" of this group. For although the natural system of animals and
-plants will never become finally settled, but will always represent a
-merely approximate knowledge of true blood relationship, still it will
-always possess great importance as a hypothetical pedigree. It is true,
-by a "natural system" most zoologists and botanists only endeavour to
-express in a concise way the subjective conceptions which each has
-formed of the objective "_form-relationships_" of organisms. These
-form-relationships, however, as the reader has seen, are in reality the
-necessary result of true _blood relationship_. Consequently, every
-morphologist in promoting our knowledge of the natural system, at the
-same time promotes our knowledge of the pedigree, whether he wishes it
-or not. The more the natural system deserves its name, and the more
-firmly it is established upon the concordance of results obtained from
-the study of comparative anatomy, ontogeny, and palaeontology, the more
-surely may we consider it as the approximate expression of the true
-pedigree of the organic world.
-
-In entering upon the task contemplated in this chapter, the genealogy of
-the vegetable kingdom, we shall have, according to this principle, first
-to glance at the _natural system of the vegetable kingdom_ as it is at
-present (with more or less important modifications) adopted by most
-botanists. According to the system generally in vogue, the whole series
-of vegetable forms is divided into two main groups. These main
-divisions, or sub-kingdoms, are the same as were distinguished more than
-a century ago by Charles Linnaeus, the founder of systematic natural
-history, and which he called _Cryptogamia_, or secretly-blossoming
-plants, and _Phanerogamia_, or openly-flowering plants. The latter,
-Linnaeus, in his artificial system of plants, divided, according to the
-different number, formation, and combination of the anthers, and also
-according to the distribution of the sexual organs, into twenty-three
-different classes, and then added the Cryptogamia to these as the
-twenty-fourth and last class.
-
-The _Cryptogamia_, the secretly-blossoming or flowerless plants, which
-were formerly but little observed, have in consequence of the careful
-investigations of recent times been proved to present such a great
-variety of forms, and such a marked difference in their coarser and
-finer structure, that we must distinguish no less than fourteen
-different classes of them; whereas the number of classes of flowering
-plants, or _Phanerogamia_, may be limited to four. However, these
-_eighteen classes of the vegetable kingdom_ can again be naturally
-grouped in such a manner that we are able to distinguish in all _six
-main divisions_ or _branches_ of the vegetable kingdom. Two of these six
-branches belong to the flowering, and four to the flowerless plants. The
-table on page 82 shows how the eighteen classes are distributed among
-the six branches, and how these again fall under the _sub-kingdoms_ of
-the vegetable kingdom.
-
-The one sub-kingdom of the _Cryptogamia_ may now be naturally divided
-into _two_ divisions, or sub-kingdoms, differing very essentially in
-their internal structure and in their external form, namely, the Thallus
-plants and the Prothallus plants. The group of _Thallus plants_
-comprises the two large branches of Tangles, or Algae, which live in
-water, and the Thread-plants, or Inophytes (Lichens and Fungi), which
-grow on land, upon stones, bark of trees, upon decaying bodies, etc. The
-group of _Prothallus plants_, on the other hand, comprises the two
-branches of Mosses and Ferns, containing a great variety of forms.
-
-All _Thallus plants, or Thallophytes_, can be directly recognized from
-the fact that the two morphological fundamental organs of all other
-plants, stem and leaves, cannot be distinguished in their structure. The
-complete body of all Algae and of all Thread-plants is a mass composed of
-simple cells, which is called a _lobe_, or _thallus_. This thallus is
-as yet not differentiated into axial-organs (stem and root) and
-leaf-organs. On this account, as well as through many other
-peculiarities, the Thallophytes contrast strongly with all remaining
-plants--those comprised under the two sub-kingdoms of Prothallus plants
-and Flowering plants--and for this reason the two latter sub-kingdoms
-are frequently classed together under the name of _Stemmed plants_, or
-_Cormophytes_. The following table will explain the relation of these
-three sub-kingdoms to one another according to the two different
-views:--
-
-
-                         { A. Thallus Plants      }  I. Thallus Plants
-                         {    (_Thallophyta_)     }    (_Thallophyta_)
-  I. Flowerless Plants.  {
-   (_Cryptogamia_)       {
-                         { B. Prothallus Plants   }
-                         {    (_Prothallophyta_)  }
-                                                  }  II. Stemmed Plants
-                                                  }   (_Cormophyta_)
-                                                  }
-  II. Flowering Plants   { C. Flowering Plants    }
-    (_Phanerogamia_)     {    (_Phanerogamia_)    }
-
-
-The stemmed plants, or Cormophytes, in the organization of which the
-difference of axial-organs (stem and root) and leaf-organs is already
-developed, form at present, and have, indeed, for a very long period
-formed, the principal portion of the vegetable world. However, this was
-not always the case. In fact, stemmed plants, not only of the flowering
-group, but even of the prothallus group, did not exist at all during
-that immeasurably long space of time which forms the beginning of the
-first great division of the organic history of the earth, under the name
-of the archilithic, or primordial period. The reader will recollect that
-during this period the Laurentian, Cambrian, and Silurian systems of
-strata were deposited, the thickness of which, taken as a whole,
-amounts to about 70,000 feet. Now, as the thickness of all the more
-recent super-incumbent strata, from the Devonian to the deposits of the
-present time, taken together, amounts to only about 60,000 feet, we were
-enabled from this fact alone to draw the conclusion--which is probable
-also for other reasons--that the archilithic, or primordial, period was
-of longer duration than the whole succeeding period down to the present
-time. During the whole of this immeasurable space of time, which
-probably comprises many millions of centuries, vegetable life on our
-earth seems to have been represented exclusively by the sub-kingdom of
-Thallus plants, and, moreover, only by the class of marine Thallus
-plants, that is to say, the Algae. At least all the petrified remains
-which are positively known to be of the primordial period belong
-exclusively to this class. As all the animal remains of this immense
-period also belong exclusively to animals that lived in water, we come
-to the conclusion that at that time organisms adapted to a life on land
-did not exist at all.
-
-For these reasons the first and most imperfect of the great provinces or
-branches of the vegetable kingdom, the division of the Algae, or Tangles,
-must be of special interest to us. But, in addition, there is the
-interest which this group offers when viewed by itself. In spite of the
-exceedingly simple composition of their constituent cells, which are but
-little differentiated, the Algae show an extraordinary variety of
-different forms. To them belong the simplest and most imperfect of all
-forms, as well as very highly developed and peculiar forms. The
-different groups of Algae are distinguished as much by size of body as by
-the perfection and variety of their outer form. At the lowest stage we
-find such species as the minute Protococcus, several hundred thousands
-of which occupy a space no larger than a pin's head. At the highest
-stage we marvel at the gigantic Macrocysts, which attain a length of
-from 300 to 400 feet, the longest of all forms in the vegetable kingdom.
-It is possible that a large portion of the coal has been formed out of
-Algae. If not for these reasons, yet the Algae must excite our special
-attention from the fact that they form the beginning of vegetable life,
-and contain the original forms of all other groups of plants, supposing
-that our monophyletic hypothesis of a common origin for all groups of
-plants is correct. (Compare p. 83.)
-
-SYSTEMATIC VIEW
-
-_Of the Six Branches and Eighteen Classes of the Vegetable Kingdom._
-
-
-  ==========================================================================================
-  _Primary Groups_        |                       |                      |
-  _or Sub-Kingdoms_       | _Branches or Clades_  |    _Classes_         | _Systematic Name_
-    _of the_              |      _of the_         |     _of the_         |     _of the_
-  _Vegetable Kingdom._    | _Vegetable Kingdom._  | _Vegetable Kingdom._ |    _Classes._
-  ------------------------+-----------------------+----------------------+------------------
-
-                          {                       {  1. Primaeval algae     1. _Archephyceae_
-                          {                       {                          (Protophyta)
-                          {                       {
-                          {       I.              {  2. Green algae        2. _Chlorophyceae_
-           A.             {    Tangles            {                           (Chloroalgae)
-    =Thallus Plants=      {     _Algae_            {
-      Thallophyta         {                       {  3. Brown algae        3. _Phaeophyceae_
-                          {                       {                          (Fucoideae)
-                          {                       {
-                          {                       {  4. Red algae          4. _Rhodophyceae_
-                          {                       {                          (Florideae)
-
-                          {      II.              {  5. Lichens           5. _Lichenes_
-                          {  Thread-plants        {
-                          {   _Inophyta_          {  6. Fungi             6. _Fungi_
-                          {
-                          {                       {  7. Tangle-mosses     7. _Charobrya_
-                          {                       {                           (Characeae)
-                          {                       {
-                          {      III.             {  8. Liverworts        8. _Thallobrya_
-                          {     Mosses            {                           (Hepaticae)
-                          {    _Muscinae_          {
-                          {                       {  9. Frondose-mosses   9. _Phyllobrya_
-           B.             {                       {                           (Frondosae)
-      =Prothallus=        {                       {
-        =Plants=          {                       { 10. Turf-mosses       10. _Sphagnobrya_
-     Prothallophyta       {                                                    (Sphagnaceae)
-                          {
-                          {                       { 11. Shaft-ferns       11. _Calamariae_
-                          {                       {                          (Calamophyta)
-                          {      IV.              {
-                          {     Ferns             { 12. Frondose-ferns    12. _Filices_
-                          {   _Felicinae_          {                           (Pterideae)
-                          {                       {
-                          {                       { 13. Aquatic ferns     13. _Rhizocarpeae_
-                          {                       {                           (Hydropterides)
-                          {                       {
-                          {                       { 14. Scale-ferns       14. _Selagineae_
-                          {                       {                           (Lepidophyta)
-
-                          {       V.              {
-                          {   Plants with         { 15. Palm-ferns        15. _Cycadeae_
-           C.             {   Naked Seeds         {
-   =Flowering Plants=     {  _Gymnosperma_        { 16. Pines             16. _Coniferae_
-      Phanerogamia        {
-                          {      VI.              { 17. Plants with       17. _Monocotylae_
-                          {  Plants with          {    one seed lobe
-                          { Enclosed Seeds        {
-                          {  _Angiosperma_        { 18. Plants with       18. _Dicotylae_
-                          {                       {    two seed lobes
-
-             ----------------------------------------------------------------
-
-
-              _Gamopetalae_
-         (Flowers with corolla)
-                    |
-            _Dialypetalae_
-         (Star-shaped flowers)
-                    |
-             _Monochlamydeae_                    MONOCOTYLEDONAE
-          (Flowers with calyx)             (One seed-lobed plants)
-                    |                                  |
-              DICOTYLEDONAE                             |
-         (Two seed-lobed plants)                       |
-                    |                                  |
-                    \--------------------v-------------/
-              CONIFERAE             +Angiospermae+
-  CYCADEAE     (Pines)         (Plants with enclosed seeds)
-  (Palm-ferns)   |       GNETACEAE        |
-     |           |           |           |
-     \-----------v-----------------------/
-           +Gymnospermae+
-    (Plants with naked seeds)   _Phanerogamae_
-                 |            (Flowering plants) _Pterideae_
-  _Selagineae_    | _Rhizocarpeae_      |       (Frondose-ferns)
-  (Scaled-ferns) |(Water-ferns)       |              |    _Calamariae_
-      |          |      |             |              |   (Shaft-ferns)
-      |          |      |             |              |         |
-      \-------------------------------v------------------------/
-                                  +Filicinae+
-    _Frondosae_     _Sphagnaceae_    (Ferns)
-   (Leaf-mosses)  (Turf-mosses)       |
-        |                |            |                      CHARACEAE
-        \----------------v------------/                   (Tangle-mosses)
-                         |                                       |
-               _Hepaticae_ (Liverworts)                           |
-                         |                                       |
-                         \------------------v--------------------/
-                                        +Muscinae+ (Mosses)
-                     _Fucoideae_             |
-  _Florideae_        (Brown Algae)            |                _Lichenes_
-  (Red Algae)              |           _Chlorophyceae_         (Lichens)
-       |                  |            (Green Algae)              |
-       |                  |                 |                    |
-       \------------------v-----------------/            +Fungi Inophyta+
-                   +Algae+ (Tangles)                        (Thread-plants)
-                          |                                      |
-                          \-------v------------------------------/
-                              _Protophyta_
-                           (Primaeval Plants)
-                                  |
-                          _Vegetable Monera_
-
-Most people living inland can form but a very imperfect idea of this
-exceedingly interesting branch of the vegetable kingdom, because they
-know only its proportionately small and simple representatives living in
-fresh water. The slimy green aquatic filaments and flakes of our pools
-and ditches and springs, the light green slimy coverings of all kinds of
-wood which have for any length of time been in contact with water, the
-yellowish green, frothy, and oozy growths of our village ponds, the
-green filaments resembling tufts of hair which occur everywhere in fresh
-water, stagnant and flowing, are for the most part composed of different
-species of Algae. Only those who have visited the sea-shore, and wondered
-at the immense masses of cast-up seaweed, and who, from the rocky coast
-of the Mediterranean, have seen through the clear blue waters the
-beautifully-formed and highly-coloured vegetation of Algae at the bottom,
-know how to estimate the importance of the class of Algae. And yet, even
-these marine Algae-forests of European shores, so rich in forms, give
-only a faint idea of the colossal forests of Sargasso in the Atlantic
-ocean, those immense banks of Algae, covering a space of about 40,000
-square miles--the same which made Columbus, on his voyage of discovery,
-believe that a continent was near. Similar but far more extensive
-forests of Algae grew in the primaeval ocean, probably in dense masses,
-and what countless generations of these archilithic Algae have died out
-one after another is attested, among other facts, by the vast thickness
-of Silurian alum schists in Sweden, the peculiar composition of which
-proceeds from those masses of submarine Algae. According to the recently
-expressed opinion of Frederick Mohr, a geologist of Bonn, even the
-greater part of our coal seams have arisen out of the accumulated dead
-bodies of the Algae forests of the ocean.
-
-Within the branch of the Algae we distinguish four different classes,
-each of which is again divided into several orders and families. These
-again contain a large number of different genera and species. We
-designate these four classes as Primaeval Algae, or Archephyceae, Green
-Algae, or Chlorophyceae, Brown Algae, or Phaeophyceae, and Red Algae, or
-Rhodophyceae.
-
-The first class of Algae, the _Primaeval_ Algae (Archephyceae), might also
-be called _primaeval plants_, because they contain the simplest and most
-imperfect of all plants, and, among them, those most ancient of all
-vegetable organisms out of which all other plants have originated. To
-them therefore belong those most ancient of all vegetable Monera which
-arose by spontaneous generation in the beginning of the Laurentian
-period. Further, we have to reckon among them all those vegetable forms
-of the simplest organization which first developed out of the Monera in
-the Laurentian period, and which possessed the form of a single
-plastid. At first the entire body of one of these small primary plants
-consisted only of a most simple cytod (a plastid without kernel), and
-afterwards attained the higher form of a simple cell, by the separation
-of a kernel in the plasma. (Compare above, vol. i. p. 345.) Even at the
-present day there exist various most simple forms of Algae which have
-deviated but little from the original primary plants. Among them are the
-Algae of the families Codiolaceae, Protococcaceae, Desmidiaceae,
-Palmellaceae, Hydrodictyeae, and several others. The remarkable group of
-Phycochromaceae (Chroococcaceae and Oscillarineae) might also be comprised
-among them, unless we prefer to consider them as an independent tribe of
-the kingdom Protista.
-
-The monoplastic Protophyta--that is, those primary Algae formed by a
-single plastid--are of the greatest interest, because the vegetable
-organism in this case completes its whole course of life as a perfectly
-simple "individual of the first order," either as a cytod without
-kernel, or as a cell containing a kernel.
-
-Among the primary plants consisting of a single cytod are the
-exceedingly remarkable Siphoneae, which are of considerable size, and
-strangely "mimic" the forms of higher plants. Many of the Siphoneae
-attain a size of several feet, and resemble an elegant moss (Bryopsis),
-or in some cases a perfect flowering plant with stalks, roots, and
-leaves (Caulerpa) (Fig. 17). Yet the whole of this large body,
-externally so variously differentiated, consists internally of an
-entirely simple sack, possessing the negative characters of a simple
-cytod.
-
-[Illustration: FIG. 17.--Caulerpa denticulata, a monoplastic Siphonean
-_of the natural size_. The entire branching primary plant, which appears
-to consist of a creeping stalk with fibrous roots and indented leaves,
-is in reality only _a single plastid_, and moreover a cytod (without a
-kernel), not even attaining the grade of a cell with nucleus.]
-
-These curious Siphoneae, Vaucheriae, and Caulerpae show us to how great a
-degree of elaboration a single cytod, although a most simple individual
-of the first order, can develop by continuous adaptation to the
-relations of the outer world. Even the _single-celled primary
-plants_--which are distinguished from the monocytods by possessing a
-kernel--develop into a great variety of exquisite forms by adaptation;
-this is the case especially with the beautiful _Desmidiaceae_, of which
-a species of Euastrum is represented in Fig. 18 as a specimen.
-
-[Illustration: FIG. 18.--Euastrum rota, a single-celled Desmid, much
-enlarged. The whole of the star-shaped body of this primaeval plant has
-the formal value of a simple cell. In its centre lies the kernel, and
-within this the kernel corpuscle, or speck.]
-
-It is very probable that similar primaeval plants, the soft body of
-which, however, was not capable of being preserved in a fossil state, at
-one time peopled the Laurentian primaeval sea in great masses and
-varieties, and in a great abundance of forms, without, however, going
-beyond the stage of individuality of a simple plastid.
-
-The group of _Green Tangles_ (Chlorophyceae), or _Green Algae_
-(Cloroalgae), are the second class, and the most closely allied to the
-primaeval group. Like the majority of the Archephyceae, all the
-Chlorophyceae are coloured green, and by the same colouring matter--the
-substance called leaf-green, or chlorophyll--which colours the leaves of
-all the higher plants.
-
-To this class belong, besides a great number of low marine Algae, most of
-the Algae of fresh water, the common water hair-weeds, or Confervae, the
-green slime-balls, or Gloeosphaerae, the bright green water-lettuce, or
-Ulva, which resembles a very thin and long lettuce leaf, and also
-numerous small microscopic algae, dense masses of which form a light
-green shiny covering to all sorts of objects lying in water--wood,
-stones, etc.
-
-These forms, however, rise above the simple primary Algae in the
-composition and differentiation of their body. As the green Algae, like
-the primaeval Algae, mostly possess a very soft body, they are but rarely
-capable of being petrified. However, it can scarcely be doubted that
-this class of Algae--which was the first to develop out of the preceding
-one--most extensively and variously peopled the fresh and salt waters of
-the earth in early times.
-
-In the third class, that of the _Brown Tangles_ (Phaeophyceae), or _Black
-Algae_ (Fucoideae), the _branch_ of the Algae attains its highest stage of
-development, at least in regard to size and body. The characteristic
-colour of the Fucoid is more or less dark brown, sometimes tending more
-to an olive green or yellowish green, sometimes more to a brownish red
-or black colour.
-
-Among these are the largest of all Algae, which are at the same time the
-longest of all plants, namely, the colossal giant Algae, amongst which
-the Macrocystis pyrifera, on the coast of California, attains a length
-of 400 feet. Also, among our indigenous Algae, the largest forms belong
-to this group. Especially I may mention here the stately sugar-tangle
-(Laminaria), whose slimy, olive green thallus-body, resembling gigantic
-leaves of from 10 to 15 feet in length, and from a half to one foot in
-breadth, are thrown up in great masses on the coasts of the North and
-Baltic seas.
-
-To this class belongs also the bladder-wrack (Fucus vesiculosus) common
-in our seas, whose fork-shaped, deeply-cut leaves are kept floating on
-the water by numerous air bladders (as is the case, too, with many other
-brown Algae). The freely floating Sargasso Alga (Sargasso bacciferum),
-which forms the meadows or forests of the Sargasso Sea, also belongs to
-this class.
-
-Although each individual of these large alga-trees is composed of many
-millions of cells, yet at the beginning of its existence it consists,
-like all higher plants, of a single cell--a simple egg. This egg--for
-example, in the case of our common bladder-wrack--is a naked, uncovered
-cell, and as such is so like the naked egg-cells of lower marine
-animals--for example, those of the Medusae--that they might easily be
-mistaken one for another (Fig. 19).
-
-[Illustration: FIG. 19.--The egg of the common bladder-wrack (Fucus
-vesiculosus), a simple naked cell, much enlarged. In the centre of the
-naked globule of protoplasm the bright kernel is visible.]
-
-It was probably the Fucoideae, or Brown Algae, which during the primordial
-period, to a great extent constituted the characteristic alga-forests of
-that immense space of time. Their petrified remains, especially those
-of the Silurian period, which have been preserved, can, it is true,
-give us but a faint idea of them, because the material of these Algae,
-like that of most others, is ill-suited for preservation in a fossil
-state. As has already been remarked, a large portion of coal is perhaps
-composed of them.
-
-Less important is the fourth class of Algae, that of the _Rose-coloured
-Algae_ (Rhodophyceae), or _Red Sea-weeds_ (Florideae). This class, it is
-true, presents a great number of different forms; but most of them are
-of much smaller size than the Brown Algae. Although they are inferior to
-the latter in perfection and differentiation, they far surpass them in
-some other respects. To them belong the most beautiful and elegant of
-all Algae, which on account of the fine plumose division of their
-leaf-like bodies, and also on account of their pure and delicate red
-colour, are among the most charming of plants. The characteristic red
-colour sometimes appears as a deep purple, sometimes as a glowing
-scarlet, sometimes as a delicate rose tint, and may verge into violet
-and bluish purple, or on the other hand into brown and green tints of
-marvellous splendour. Whoever has visited one of our sea-coast watering
-places, must have admired the lovely forms of the Florideae, which are
-frequently dried on white paper and offered for sale.
-
-Most of the Red Algae are so delicate, that they are quite incapable of
-being petrified; this is the case with the splendid Ptilotes, Plocamia,
-Delesseria, etc. However, there are individual forms, like the Chondria
-and Sphaerococca, which possess a harder thallus, often almost as hard as
-cartilage, and of these fossil remains have been preserved--principally
-in the Silurian, Devonian, and Carboniferous strata, and later in the
-oolites. It is probable that this class also had an important share in
-the composition of the archilithic Algae flora.
-
-If we now again take into consideration the flora of the primordial
-period, which was exclusively formed by the group of Algae, we can see
-that it is not improbable that its four subordinate classes had a share
-in the composition of those submarine forests of the primaeval oceans,
-similar to that which the four types of vegetation--trees with trunks,
-flowering shrubs, grass, and tender leaf-ferns and mosses--at present
-take in the composition of our recent land forests.
-
-We may suppose that the submarine tree forests of the primordial period
-were formed by the huge Brown Algae, or Fucoideae. The many-coloured
-flowers at the foot of these gigantic trees were represented by the gay
-Red Algae, or Florideae. The green grass between was formed by the
-hair-like bunches of Green Algae, or Chloroalgae. Finally, the tender
-foliage of ferns and mosses, which at present cover the ground of our
-forests, fill the crevices left by other plants, and even settle on the
-trunks of the trees, at that time probably had representatives in the
-moss and fern-like Siphoneae, in the Caulerpa and Bryopsis, from among
-the class of the primary Algae, Protophyta, or Archephyceae.
-
-With regard to the relationships of the different classes of Algae to one
-another and to other plants, it is exceedingly probable that the Primary
-Algae, or Archephyceae, as already remarked, form the common root of the
-pedigree, not merely for the different classes of Algae, but for the
-whole vegetable kingdom. On this account they may with justice be
-designated as primaeval plants, or Protophyta.
-
-Out of the naked vegetable Monera, in the beginning of the Laurentian
-period, enclosed cytods were probably the first to arise (vol. i. p.
-345), by the naked, structureless, albuminous substance of the Monera
-becoming condensed in the form of a pellicle on the surface, or by
-secreting a membrane. At a later period, out of these enclosed cytods
-genuine vegetable cells probably arose, as a kernel or nucleus separated
-itself in the interior from the surrounding cell-substance or plasma.
-
-The three classes of Green Algae, Brown Algae, and Red Algae, are perhaps
-three distinct classes, which have arisen independently of one another
-out of the common radical group of Primaeval Algae, and then developed
-themselves further (each according to its kind), and have variously
-branched off into orders and families. The Brown and Red Algae possess no
-close blood relationship to the other classes of the vegetable kingdom.
-These latter have most probably arisen out of the Primaeval Algae, either
-directly or by the intermediate step of the Green Algae.
-
-It is probable that Mosses (out of which, at a later time, Ferns
-developed) proceeded from a group of Green Algae, and that Fungi and
-Lichens proceeded from a group of Primaeval Algae. The Phanerogamia
-developed at a much later period out of Ferns.
-
-As a second class of the Vegetable Kingdom we have above mentioned the
-_Thread-plants_ (Inophyta). We understood by this term the two closely
-related classes of _Lichens_ and _Fungi_. It is possible that these
-Thallus plants have not arisen out of the Primaeval Algae, but out of one
-or more Monera, which, independently of the latter, arose by spontaneous
-generation. It appears conceivable that many of the lowest Fungi, as for
-example, many ferment-causing fungi (forms of Micrococcus, etc.), owe
-their origin to a number of different _archigonic_ Monera (that is,
-Monera originating by spontaneous generation).
-
-In any case the Thread-plants cannot be considered as the progenitors of
-any of the higher vegetable classes. Lichens, as well as fungi, are
-distinct from the higher plants in the composition of their soft bodies,
-consisting as it does of a dense felt-work of very long, variously
-interwoven, and peculiar threads or chains of cells--the so-called
-_hyphae_, on which account we distinguish them as a province under the
-name Thread-plants. From their peculiar nature they could not leave any
-important fossil remains, and consequently we can form only a very vague
-guess at their palaeontological development.
-
-The first class of Thread-plants, the _Fungi_, exhibit a very close
-relationship to the lowest Algae; the Algo-fungi, or Phycomycetes (the
-Saprolegniae and Peronosporae) in reality only differ from the
-bladder-wracks and Siphoneae (the Vaucheria and Caulerpa) mentioned
-previously by the want of leaf-green, or chlorophyll. But, on the other
-hand, all genuine Fungi have so many peculiarities, and deviate so much
-from other plants, especially in their mode of taking food, that they
-might be considered as an entirely distinct province of the vegetable
-kingdom.
-
-Other plants live mostly upon inorganic food, upon simple combinations
-which they render more complicated. They produce protoplasm by the
-combination of water, carbonic acid, and ammonia. They take in carbonic
-acid and give out oxygen. But the Fungi, like animals, live upon organic
-food, consisting of complicated combinations of carbon, which they
-receive from other organisms and assimilate. They inhale oxygen and
-give out carbonic acid like animals. They also never form leaf-green, or
-chlorophyll, which is so characteristic of most other plants. In like
-manner they never produce starch. Hence many eminent botanists have
-repeatedly proposed to remove the Fungi completely out of the vegetable
-kingdom, and to regard them as a special and third kingdom, between that
-of animals and plants. By this means our kingdom of Protista would be
-considerably increased. The Fungi in this case would, in the first
-place, be allied to the so-called "slime moulds," or Myxomycetes (which,
-however, never form any hyphae). But as many Fungi propagate in a sexual
-manner, and as most botanists, according to the prevalent opinion, look
-upon Fungi as genuine plants, we shall here leave them in the vegetable
-kingdom, and connect them with lichens, to which they are at all events
-most nearly related.
-
-The phyletic origin of Fungi will probably long remain obscure. The
-close relationship already hinted at between the Phycomycetes and
-Siphoneae (especially between the Saprolegniae and Vaucheriae) suggests to
-us that they are derived from the latter. Fungi would then have to be
-considered as Algae, which by adaptation to a parasitical life have
-become very peculiarly transformed. Many facts, however, support the
-supposition that the lowest fungi have originated independently from
-archigonic Monera.
-
-The second class of Inophyta, the _Lichens_ (Lichenes), are very
-remarkable in relation to phylogeny; for the surprising discoveries of
-late years have taught us that every Lichen is really composed of two
-distinct plants--of a low form of Alga (Nostochaceae, Chroococcaceae), and
-of a parasitic form of Fungus (Ascomycetes), which lives as a parasite
-upon the former, and upon the nutritive substances prepared by it. The
-green cells, containing chlorophyll (gonidia), which are found in every
-lichen, belong to the Alga. But the colourless threads (hyphae) which,
-densely interwoven, form the principal mass of the body of Lichens,
-belong to the parasitic Fungus. But in all cases the two forms of
-plants--Fungus and Alga--which are always considered as members of two
-quite distinct provinces of the vegetable kingdom, are so firmly united,
-and so thoroughly interwoven, that nearly every one looks upon a Lichen
-as a single organism.
-
-Most Lichens form small, more or less formless or irregularly indented,
-crust-like coverings to stones, bark of trees, etc. Their colour varies
-through all possible tints, from the purest white to yellow, red, green,
-brown, and the deepest black.
-
-Many lichens are important in the economy of nature from the fact that
-they can settle in the driest and most barren localities, especially on
-naked rocks upon which no other plant can live. The hard black lava,
-which covers many square miles of ground in volcanic regions, and which
-for centuries frequently presents the most determined opposition to the
-life of every kind of vegetation, is always first occupied by Lichens.
-It is the white or grey Lichens (Stereocaulon) which, in the most
-desolate and barren fields of lava, always begin to prepare the naked
-rocky ground for cultivation, and conquer it for subsequent higher
-vegetation. Their decaying bodies form the first mould in which mosses,
-ferns, and flowering plants can afterwards take firm root. Hardy Lichens
-are also less affected by the severity of climate than any other plants.
-Hence the naked rocks, even in the highest mountains--for the most part
-covered by eternal snow, on which no plant could thrive--are encrusted
-by the dry bodies of Lichens.
-
-Leaving now the Fungi, Lichens, and Algae, which are comprised under the
-name of Thallus plants, we enter upon the second sub-kingdom of the
-vegetable kingdom, that of the _Prothallus plants_ (Prothallophyta),
-which by some botanists are called phyllogonic Cryptogamia (in
-contradistinction to the Thallus plants, or thallogonic Cryptogamia).
-This sub-kingdom comprises the two provinces of _Mosses_ and _Ferns_.
-
-Here we meet with (except in a few of the lowest forms) the separation
-of the vegetable body into two different fundamental organs,
-axial-organs (stem and root) and leaves (or lateral organs). In this the
-Prothallus plants resemble the Flowering plants, and hence the two
-groups have recently often been classed together as stemmed plants, or
-Cormophytes.
-
-But, on the other hand, Mosses and Ferns resemble the Thallus plants, in
-the absence of the development of flowers and seeds, and even Linnaeus
-classed them with these, as Cryptogamia, in contradistinction to the
-plants forming seeds; that is, flowering plants (Anthophyta or
-Phanerogamia).
-
-Under the name of "Prothallus plants" we combine the closely-related
-Mosses and Ferns, because both exhibit a peculiar and characteristic
-"alternation of generation" in the course of their individual
-development. For every species exhibits two different generations, of
-which the one is usually called the _Prothallium_, or _Fore-growth_, the
-other is spoken of as the _Cormus_, or actual _Stem_ of the moss or
-fern.
-
-The first and original generation, the Fore-growth, or Prothallus, also
-called Protonema, still remains in that lower stage of elaboration
-manifested throughout life by all Thallus plants; that is to say, stem
-and leaf-organs have as yet not differentiated, and the entire cell-mass
-of the Fore-growth corresponds to a simple thallus. The second and more
-perfect generation of mosses and ferns--the Stem, or Cormus--develops a
-much more highly elaborate body, which has differentiated into stalk and
-leaf (as in the case of flowering plants), except in the lowest mosses,
-where this generation also remains in the lower stage of the thallus.
-
-With the exception of these latter forms the first generation of Mosses
-and Ferns (the thallus-shaped Fore-growth) always produces a second
-generation with stem and leaves; the latter in its turn produces the
-thallus of the first generation, and so on. Thus, in this case, as in
-the ordinary cases of alternation of generation in animals, the first
-generation is like the third, fifth, etc., the second like the fourth,
-sixth, etc. (Compare vol. i. p. 206.)
-
-Of the two main classes of Prothallus plants, the Mosses in general are
-at a much lower stage of development than the Ferns, and their lowest
-forms (especially in an anatomical respect) form the transition from the
-Thallus plants through the Algae to Ferns. The genealogical connection of
-Mosses and Ferns which is indicated by this fact can, however, be
-inferred only from the case of the most imperfect forms of the two
-classes; for the more perfect and higher groups of mosses and ferns do
-not stand in any close relation to one another, and develop in
-completely opposite directions. In any case Mosses have arisen directly
-out of Thallus plants, and probably out of Green Algae.
-
-Ferns, on the other hand, are probably derived from extinct unknown
-Mosses, which were very nearly related to the lowest liverworts of the
-present day. In the history of creation, Ferns are of greater importance
-than Mosses.
-
-The branch of _Mosses_ (Muscinae, also called Musci, or Bryophyta)
-contains the lower and more imperfect plants of the group of
-Prothallophytes, which as yet do not possess vessels. Their bodies are
-mostly so tender and perishable that they are very ill-suited for being
-preserved in a recognizable state as fossils. Hence the fossil remains
-of all classes of Mosses are rare and insignificant. It is probable that
-Mosses developed in very early times out of the Thallus plants, or, to
-be more precise, out of the Green Algae. It is probable that in the
-primordial period there existed aquatic forms of transition from the
-latter to Mosses, and in the primary period to those living on land. The
-Mosses of the present day--out of the gradually differentiating
-development of which comparative anatomy may draw some inferences as to
-their genealogy--are divided into two different classes, namely: (1)
-Liverworts; (2) Leafy Mosses.
-
-The first and oldest class of Mosses, which is directly allied to the
-Green Algae, or Confervae, is formed by the _Liverworts_ (Hepaticae, or
-Thallobrya). The mosses belonging to them are, for the most part, small
-and insignificant in form, and are little known. Their lowest forms
-still possess, in both generations, a simple thallus like the Thallus
-plants; as for example, the Ricciae and Marchantiaceae. But the more
-highly developed liverworts, the Jungermanniaceae and those akin to them,
-gradually commence to differentiate stem and leaf, and their most
-highly-developed forms are closely allied to leaf-mosses. By this
-transitional series the liverworts show their direct derivation from
-the Thallophytes, and more especially from the Green Algae.
-
-The Mosses, which are generally the only ones known to the
-uninitiated--and which, in fact, form the principal portion of the whole
-branch--belong to the second class, or _Leafy Mosses_ (Musci frondosi,
-called Musci in a narrow sense, also Phyllobrya). Among them are most of
-those pretty little plants which, united in dense groups, form the
-bright glossy carpet of moss in our woods, or which, in company with
-liverworts and lichens, cover the bark of trees. As reservoirs,
-carefully storing up moisture, they are of the greatest importance in
-the economy of nature. Wherever man mercilessly cuts down and destroys
-forests, there, as a consequence, disappear the leafy mosses which
-covered the bark of the trees, or, protected by their shade, clothed the
-ground, and filled the spaces between the larger plants. Together with
-the leafy mosses disappear the useful reservoirs which stored up rain
-and dew for times of drought. Thus arises a disastrous dryness of the
-ground, which prevents the growth of any rich vegetation. In the greater
-part of Southern Europe--in Greece, Italy, Sicily, and Spain--mosses
-have been destroyed by the inconsiderate extirpation of forests, and the
-ground has thereby been robbed of its most useful stores of moisture;
-once flourishing and rich tracts of land have been changed into dry and
-barren wastes. Unfortunately in Germany, also, this rude barbarism is
-beginning to prevail more and more. It is probable that the small
-frondose mosses have played this exceedingly important part in nature
-for a very long time, possibly from the beginning of the primary period.
-But as their tender bodies are as little suited as those of all other
-mosses for being preserved in a fossil state, palaeontology can give us
-no information about this.
-
-We learn from the science of petrifactions much more than we do in the
-case of Mosses of the importance which the second branch of Prothallus
-plants--that is, Ferns--have had in the history of the vegetable world.
-Ferns, or more strictly speaking, the "plants of the fern tribe"
-(Filicineae, or Pterideae, also called Pteridophyta, or Vascular
-Cryptogams), formed during an extremely long period, namely, during the
-whole primary or palaeolithic period, the principal portion of the
-vegetable world, so that we may without hesitation call it the _era of
-Fern Forests_. From the beginning of the Devonian period, in which
-organisms living on land appeared for the first time, namely, during the
-deposits of the Devonian, Carboniferous, and Permian strata, plants like
-Ferns predominated so much over all others, that we are justified in
-giving this name to that period. In the stratifications just mentioned,
-but above all, in the immense layers of coal of the Carboniferous or
-coal period, we find such numerous and occasionally well preserved
-remains of Ferns, that we can form a tolerable vivid picture of the very
-peculiar land flora of the palaeolithic period. In the year 1855 the
-total number of the then known palaeolithic species of plants amounted to
-about a thousand, and among these there were no less than 872 Ferns.
-Among the remaining 128 species were 77 Gymnosperms (pines and
-palm-ferns), 40 Thallus plants (mostly Algae), and about 20 not
-accurately definable Cormophyta (stem-plants).
-
-As already remarked, Ferns probably developed out of the lower
-liverworts in the beginning of the primary period. In their
-organization Ferns rise considerably above Mosses, and in their more
-highly developed forms even approach the flowering plants. In Mosses, as
-in Thallus plants, the entire body is composed of almost equi-formal
-cells, little if at all differentiated; but in the tissues of Ferns we
-find those peculiarly differentiated strings of cells which are called
-the vessels of plants, and which are universally met with in flowering
-plants. Hence Ferns are sometimes united as "vascular Cryptogams" with
-Phanerogams, and the group so formed is contrasted as that of the
-"vascular plants" with "cellular plants,"--that is, with "cellular
-cryptogams" (Mosses and Thallus plants). This very important process in
-the organization of plants--the formation of vessels--first occurred,
-therefore, in the Devonian period, consequently in the beginning of the
-second and smaller half of the organic history of the earth.
-
-The branch of Ferns, or Filicinae, is divided into five distinct classes:
-(1) Frondose Ferns, or Pteridae; (2) Reed Ferns, or Calamariae; (3)
-Aquatic Ferns, or Rhizocarpeae; (4) Snakes Tongues, or Ophioglossae; and
-(5) Scale Ferns, or Lepidophyta. By far the most important of these five
-classes, and also the richest in forms, were first the Frondose Ferns,
-and then the Scale-ferns, which formed the principal portion of the
-palaeolithic forests. The Reed Ferns, on the other hand, had at that time
-already somewhat diminished in number; and of the Aquatic Ferns, we do
-not even know with certainty whether they then existed. It is difficult
-for us to form any idea of the very peculiar character of those gloomy
-palaeolithic fern forests, in which the whole of the gay abundance of
-flowers of our present flora was entirely wanting, and which were not
-enlivened by any birds. Of the flowering plants there then existed only
-the two lowest classes, the pines and palm ferns, with naked seeds,
-whose simple and insignificant blossoms scarcely deserve the name of
-flowers.
-
-The phylogeny of Ferns, and of the Gymnosperms which have developed out
-of them, has been made especially clear by the excellent investigations
-which Edward Strasburger published in 1872, on "The Coniferae and
-Gnetaceae," as also "On Azolla." This thoughtful naturalist and Charles
-Martins, of Montpellier, are among the few botanists who have thoroughly
-understood the fundamental value of the Theory of Descent, and the
-mechanical-causal connection between ontogeny and phylogeny. The
-majority of botanists do not even yet know the important difference
-between homology and analogy, between the morphological and
-physiological comparison of parts--which has long since been recognized
-in zoology--but Strasburger has employed this distinction and the
-principle of evolution in his "Comparative Anatomy of the Gymnosperms,"
-in order to sketch the outlines of the blood relationship of this
-important group of plants.
-
-The class among Ferns which has developed most directly out of the
-Liverworts is the class of real Ferns, in the narrow sense of the word,
-the _Frondose Ferns_ (Filices, or Phyllopterides, also called Pteridae).
-In the present flora of the temperate zones this class forms only a
-subordinate part, for it is in most cases represented only by low forms
-without trunks. But in the torrid zones, especially in the moist,
-steaming forests of tropical regions, this class presents us with the
-lofty palm-like _fern trees_. These beautiful tree-ferns of the present
-day, which form the chief ornament of our hot-houses, can however give
-us but a faint idea of the stately and splendid frondose ferns of the
-primary period, whose mighty trunks, densely crowded together, then
-formed entire forests. These trunks, accumulated in super-incumbent
-masses, are found in the coal seams of the Carboniferous period, and
-between them, in an excellent state of preservation, are found the
-impressions of the elegant fan-shaped leaves, crowning the top of the
-trunk in an umbrella-like bush. The varied outlines and the
-feather-like forms of these fronds, the elegant shape of the branching
-veins or bunches of vessels in their tender foliage, can still be as
-distinctly recognized in the impressions of the palaeolithic fronds as in
-the fronds of ferns of the present day. In many cases even the clusters
-of fruit, which are distributed on the lower surface of the fronds, are
-distinctly preserved. After the Carboniferous period, the predominance
-of frondose ferns diminished, and towards the end of the secondary
-period they played almost as subordinate a part as they do at the
-present time.
-
-The Calamariae, Ophioglossae, and Rhizocarpeae seem to have developed as
-three diverging branches out of the Frondose Ferns, or Pteridae. The
-Calamariae, or Calamophyta, have remained at the lowest level among these
-three classes. The Calamariae comprise three different orders, of which
-only one now exists, namely, the Horse-tails (Equisetaceae). The two
-other orders, the Giant Reeds (Calamiteae), and the Star-leaf Reeds
-(Asterophylliteae), are long since extinct. All Calamariae are
-characterized by a hollow and jointed stalk, stem, or trunk, upon which
-the branches and leaves (in cases where they exist) are set so as to
-encircle the jointed stem in whorls. The hollow joints of the stalk are
-separated from one another by partition walls. In Horse-tails and
-Calamiteae the surface is traversed by longitudinal ribs running
-parallel, as in the case of a fluted column, and the outer skin contains
-so much silicious earth in the living forms, that it is used for
-cleansing and polishing. In the Asterophylliteae, the star-shaped whorls
-of leaves were more strongly developed than in the two other orders.
-There exist, at present, of the Calamariae only the insignificant
-Horse-tails (Equisetum), which grow in marshes and on moors; but during
-the whole of the primary and secondary periods they were represented by
-great trees of the genus Equisetites. There existed, at the same time,
-the closely related order of the Giant Reeds (Calamites), whose strong
-trunks grew to a height of about fifty feet. The order of the
-Asterophyllites, on the other hand, contained smaller and prettier
-plants, of a very peculiar form, and belongs exclusively to the primary
-period.
-
-Among all Ferns, the history of the third class, that of the _Root_, or
-_Aquatic Ferns_ (Rhizocarpeae, or Hydropteridae), is least known to us. In
-their structure these ferns, which live in fresh water, are on the one
-hand allied to the frond ferns, and on the other to the scaly ferns, but
-they are more closely related to the latter. Among them are the but
-little known moss ferns (Salvinia), clover ferns (Marsilea), and pill
-ferns (Pilularia) of our fresh waters; further, the large Azolla which
-floats in tropical ponds. Most of the aquatic ferns are of a delicate
-nature, and hence ill-suited for being petrified. This is probably the
-reason of their fossil remains being so scarce, and of the oldest of
-those known to us having been found in the Jura system. It is probable,
-however, that the class is much older, and that it was already
-developed during the palaeolithic period out of other ferns by adaptation
-to an aquatic life.
-
-The fourth class of ferns is formed by the _Tongue Ferns_ (Ophioglossae,
-or Glossopterides). These ferns, to which belongs the Botrychium, as
-well as the Ophioglossum (adder's-tongue) of our native genera, were
-formerly considered as forming but a small sub-division of the frondose
-ferns. But they deserve to form a special class, because they represent
-important transitional forms from the Pterideae and Lepidophytes towards
-higher plants, and must be regarded as among the direct progenitors of
-the flowering plants.
-
-The fifth and last class is formed by the _Scale Ferns_ (Lepidophytes,
-or Selagines). In the same way as the Ophioglossae arose out of the
-frondose forms, the scale ferns arose out of the Ophioglossae. They were
-more highly developed than all other ferns, and form the transition to
-flowering plants, which must have developed out of them. Next to the
-frondose ferns they took the largest part in the composition of the
-palaeolithic fern forests. This class also contains, as does the class of
-reed ferns, three nearly related but still very different orders, of
-which only one now exists, the two others having become extinct towards
-the end of the Carboniferous period. The scaled ferns still existing
-belong to the order of the club-mosses (Lycopodiaceae). They are mostly
-small, pretty moss-like plants, whose tender, many-branched stalk creeps
-in curves on the ground like a snake, and is densely encompassed and
-covered by small scaly leaves. The pretty creeping Lycopodium of our
-woods, which mountain tourists twine round their hats, is known to all,
-as also the still more delicate Selaginella, which under the name of
-creeping moss is used to adorn the soil of our hot-houses in the form of
-a thick carpet. The largest _club-mosses_ of the present day are found
-in the Sunda Islands, where their stalks rise to the height of
-twenty-five feet, and attain half a foot in thickness. But in the
-primary and secondary periods even larger trees of this kind were widely
-distributed, the most ancient of which probably were the progenitors of
-the pines (Lycopodites). The most important dimensions were, however,
-attained by the class of scale trees (Lepidodendreae), and by the seal
-trees (Sigillarieae). These two orders, with a few species, appear in the
-Devonian period, but do not attain their immense and astonishing
-development until the Carboniferous period, and become extinct towards
-the end of it, or in the Permian period directly following upon it. The
-scale trees, or Lepidodendreae, were probably more closely related to
-club-mosses than to Sigillarieae. They grew into splendid, straight,
-unbranching trunks which divided at the top into numerous forked
-branches. They bore a large crown of scaly leaves, and like the trunk
-were marked in elegant spiral lines by the scars left at the base of the
-leaf stalks which had fallen off. We know of scale-marked trees from
-forty to sixty feet in length, and from twelve to fifteen feet in
-diameter at the root. Some trunks are said to be even more than a
-hundred feet in length. In the coal are found still larger accumulations
-of the no less highly developed but more slender trunks of the
-remarkable seal trees, Sigillarieae, which in many places form the
-principal part of coal seams. Their roots were formerly described as
-quite a distinct vegetable form (under the name of Stigmaria). The
-Sigillarieae are in many respects very like the scale-trees, but differ
-from them and from ferns in general in many ways. They were possibly
-closely related to the extinct Devonian _Lycopterideae_, combining
-characteristic peculiarities of the club-mosses and the frondose ferns,
-which Strasburger considers as the hypothetical primary form of
-flowering plants.
-
-In leaving the dense forests of the primary period, which were
-principally composed of frond ferns (Lepidodendreae and Sigillarieae), we
-pass onwards to the no less characteristic pine forests of the secondary
-period. Thus we leave the domain of the Cryptogamia, the plants forming
-neither flowers nor seeds, and enter the second main division of the
-vegetable kingdom, namely, the sub-kingdom of the _Phanerogamia_,
-_flowering plants_ forming seeds. This division, so rich in forms,
-containing the principal portion of the present vegetable world, and
-especially the majority of plants living on land, is certainly of a much
-more recent date than the division of Cryptogamia. For it can have
-developed out of the latter only in the course of the palaeolithic
-period. We can with full assurance maintain that, during the whole
-archilithic period, hence during the first and longer half of the
-organic history of the earth, no flowering plants as yet existed, and
-that they first developed during the primary period out of Cryptogamia
-of the fern kind. The anatomical and embryological relation of
-Phanerogamia to the latter is so close, that from it we can with
-certainty infer their genealogical connection, that is, their true blood
-relationship. Flowering plants cannot have directly arisen out of
-thallus plants, nor out of mosses; but only out of ferns, or Filicines.
-Most probably the scaled ferns, or Lepidophyta, and more especially
-amongst these the Lycopodiaceae, forms closely related to the
-Selaginella of the present day, have been the direct progenitors of the
-Phanerogamia.
-
-On account of its anatomical structure and its embryological
-development, the sub-kingdom of the Phanerogamia has for a long time
-been divided into two large branches, into the _Gymnosperms_, or plants
-with naked seeds, and the _Angiosperms_, or plants with enclosed seeds.
-The latter are in every respect more perfect and more highly organized
-than the former, and developed out of them only at a late date during
-the secondary period. The Gymnosperms, both anatomically and
-embryologically, form the transition group from Ferns to Angiosperms.
-
-The lower, more imperfect, and the older of the two main classes of
-flowering plants, that of the _Archispermeae_, or _Gymnosperms_ (with
-naked seeds), attained its most varied development and widest
-distribution during the mesolithic or secondary epoch. It was no less
-characteristic of this period, than was the fern group of the preceding
-primary, and the Angiosperms of the succeeding tertiary, epoch. Hence we
-might call the secondary epoch that of Gymnosperms, or after its most
-important representatives, the era of Pine Forests. The Gymnosperms are
-divided into three classes: the Coniferae, Cycadeae, and Gnetaceae. We find
-fossil remains of the pines, or Conifers, and of the Cycads, even in
-coal, and must infer from this that the transition from scaled ferns to
-Gymnosperms took place during the Coal, or possibly even in the Devonian
-period. However, the Gymnosperms play but a very subordinate part during
-the whole of the primary epoch, and do not predominate over Ferns until
-the beginning of the secondary epoch.
-
-Of the two classes of Gymnosperms just mentioned, that of the _Palm
-Ferns_ (Zamiae, or Cycadeae) stands at the lowest stage, and is directly
-allied to ferns, as the name implies, so that some botanists have
-actually included them in the fern group. In their external form they
-resemble palms, as well as tree ferns (or tree-like frond ferns), and
-are adorned by a crown of feathery leaves, which is placed either on a
-thick, short trunk, or on a slender, simple trunk like a pillar. At the
-present day this class, once so rich in forms, is but scantily
-represented by a few forms living in the torrid zones, namely, by the
-coniferous ferns (Zamia), the thick-trunked bread-tree (Encephalartos),
-and the slender-trunked Caffir bread-tree (Cycas). They may frequently
-be seen in hot-houses, and are generally mistaken for palms. A much
-greater variety of forms than occurs among the still existing palm ferns
-(Cycadeae) is presented by the extinct and fossil Cycads, which occurred
-in great numbers more towards the middle of the secondary period, during
-the Jura, and which at that time principally determined the character of
-the forests.
-
-The class of _Pines_, or _coniferous trees_ (Coniferae), has preserved
-down to our day a greater variety of forms than have the palm ferns.
-Even at the present time the trees belonging to it--cypresses, juniper
-trees, and trees of life (Thuja), the box and ginko trees (Salisburya),
-the araucaria and cedars, but above all the genus Pinus, which is so
-rich in forms, with its numerous and important species, spruces, pines,
-firs, larches, etc.--still play a very important part in the most
-different parts of the earth, and almost of themselves constitute
-extensive forests. Yet this development of pines seems but weak in
-comparison with the predominance which the class had attained over other
-plants during the early secondary period, that of the Trias. At that
-time mighty coniferous trees--with but proportionately few genera and
-species, but standing together in immense masses of individuals--formed
-the principal part of the mesolithic forests. This fact justifies us in
-calling the secondary period the "era of the pine forests," although the
-remains of Cycadeae predominate over those of coniferous trees in the
-Jura period.[2]
-
-From the pine forests of the mesolithic, or secondary period, we pass on
-into the leafy forests of the caenolithic, or tertiary period, and we
-arrive thus at the consideration of the sixth and last class of the
-vegetable kingdom, that of the _Metaspermae_, _Angiospermae_, or _plants
-with enclosed seeds_. The first certain and undoubted fossils of plants
-with enclosed seeds are found in the strata of the chalk system, and
-indeed we here find, side by side, remains of the two classes into which
-the main class of Angiosperms is generally divided, namely, the _one
-seed-lobed plants_, or _monocotylae_, and the _two seed-lobed plants_, or
-_dicotylae_. However, the whole group probably originated at an earlier
-period during the Trias. For we know of a number of doubtful and not
-accurately definable fossil remains of plants from the Oolitic and Trias
-(sic) periods, which some botanists consider to be Monocotylae, whilst
-others consider them as Gymnosperms. In regard to the two classes of
-plants with enclosed seeds, the Monocotylae and Dicotylae, it is
-exceedingly probable that the Dicotyledons developed out of the
-Gnetaceae, but that the Monocotyledons developed later out of a branch of
-the dicotyledons.
-
-The class of _one seed-lobed plants_ (Monocotylae, or Monocotyledons,
-also called Endogenae) comprises those flowering plants whose seeds
-possess but one germ leaf or seed lobe (cotyledon). Each whorl of its
-flower contains in most cases _three_ leaves, and it is very probable
-that the mother plants of all Monocotyledons possessed a regular triple
-blossom. The leaves are mostly simple, and traversed by simple, straight
-bunches of vessels or "nerves." To this class belong the extensive
-families of the rushes, grasses, lilies, irids, and orchids, further a
-number of indigenous aquatic plants, the water-onions, sea grasses,
-etc., and finally the splendid and highly developed families of the
-Aroideae and Pandaneae, the bananas and palms. On the whole, the class of
-Monocotyledons--in spite of the great variety of forms which it
-developed, both in the tertiary and the present period--is much more
-simply organized than the class of the Dicotyledons, and its history of
-development also offers much less of interest. As their fossil remains
-are for the most part difficult to recognize, it still remains at
-present an open question in which of the three great secondary
-periods--the Trias, Jura, or chalk period--the Monocotyledons
-originated. At all events they existed in the chalk period as surely as
-did the Dicotyledons.
-
-[Illustration:
-
-  _Haeckel History of Creation._
-
-  _PL. V._
-
-Relative lengths of the 5 Epochs in percentages.
-
-  Quarternary Epoch  0.5
-  Tertiary Epoch     2.3
-  Secondary Epoch   11.5
-  Primary Epoch     32.1
-  Primordial Epoch  53.6
-                   -----
-          _Total_  100.0
-
-  Single-stemmed or
-  MONOPHYLETIC PEDIGREE
-  of the
-  VEGETABLE KINGDOM
-  based on Palaeontology.]
-
-The second class of plants with enclosed seeds, the _two seed-lobed_
-(Dicotylae, or Dicotyledons, also called Exogenae) presents much greater
-historical and anatomical interest in the development of its subordinate
-groups. The flowering plants of this class generally possess, as their
-name indicates, two seed lobes or germ leaves (cotyledons). The number
-of leaves composing its blossom is generally not three, as in most
-Monocotyledons, but four, five, or a multiple of those numbers. Their
-leaves, moreover, are generally more highly differentiated and more
-composite than those of the Monocotyledons; they are traversed by
-crooked, branching bunches of vessels or "veins." To this class belong
-most of the leafed trees, and as they predominate in the tertiary period
-as well as, at present, over the Gymnosperms and Ferns, we may call the
-caenolithic period that of leafed forests.
-
-Although the majority of Dicotyledons belong to the most highly
-developed and most perfect plants, still the lowest division of them is
-directly allied to the Gymnosperms, and particularly to the Gnetaceae. In
-the lower Dicotyledons, as in the case of the Monocotyledons, calyx and
-corolla are as yet not differentiated. Hence they are called _Apetalous_
-(Monochlamydeae, or Apetalae). This sub-class must therefore doubtless be
-looked upon as the original group of the Angiosperms, and existed
-probably even during the Trias and Jura periods. Among them are most of
-the leafed trees bearing catkins--birches and alders, willows and
-poplars, beeches and oaks; further, the plants of the nettle
-kind--nettles, hemp, and hops, figs, mulberries, and elms; finally,
-plants like the spurges, laurels, and amaranth.
-
-It was not until the chalk period that the second and more perfect class
-of the Dicotyledons appeared, namely, the _group with corollas_
-(Dichlamydeae, or Corolliflorae). These arose out of the Apetalae from the
-simple cover of the blossoms of the latter becoming differentiated into
-calyx and corolla. The sub-class of the Corolliflorae is again divided
-into two large main divisions or legions, each of which contains a large
-number of different orders, families, genera, and species. The first
-legion bears the name of star-flowers, or Diapetalae, the second that of
-the bell-flowers, or Gamopetalae.
-
-The lower and less perfect of the two legions of the Corolliflorae are
-the star-flowers (also called Diapetalae or Dialypetalae). To them belong
-the extensive families of the Umbelliferae, or umbrella-worts (wild
-carrot, etc.), the Cruciferae, or cruciform blossoms (cabbage, etc.);
-further, the Ranunculaceae (buttercups) and Crassulaceae, the Mallows and
-Geraniums, and, besides many others, the large group of Roses (which
-comprise, besides roses, most of our fruit trees), and the Pea-blossoms
-(containing, among others, beans, clover, genista, acacia, and mimosa).
-In all these Diapetalae the blossom-leaves remain separate, and never
-grow together, as is the case in the Gamopetalae. These latter developed
-first in the tertiary period out of the Diapetalae, whereas the Diapetalae
-appeared in the chalk period together with the Apetalae.
-
-The highest and most perfect group of the vegetable kingdom is formed by
-the second division of the Corolliflorae, namely, the legion of
-bell-flowers (Gamopetalae, also called Monopetalae or Sympetalae). In this
-group the blossom-leaves, which in other plants generally remain
-separate, grow regularly together into a more or less bell-like,
-funnel-shaped, or tubular flower. To them belong, among others, the
-Bell-flowers and Convolvulus, Primroses and Heaths, Gentian and
-Honeysuckle, further the family of the Olives (olive trees, privet,
-elder, and ash), and finally, besides many other families, the
-extensive division of the Lip-blossoms (Labiatae) and the Composites. In
-these last the differentiation and perfection of the Phanerogamic
-blossoms attain their highest stage of development, and we must
-therefore place them at the head of the vegetable kingdom, as the most
-perfect of all plants. In accordance with this, the legion of the
-Gamopetalae appear in the organic history of the earth later than all the
-main groups of the vegetable kingdom--in fact, not until the caenolithic
-or tertiary epoch. In the earliest tertiary period the legion is still
-very rare, but it gradually increases in the mid-tertiary, and attains
-its full development only in the latest tertiary and the quaternary
-period.
-
-Now if, having reached our own time, we look back upon the _whole
-history of the development of the vegetable kingdom_, we cannot but
-perceive in it a _grand confirmation of the Theory of Descent_. The two
-great principles of organic development which have been pointed out as
-the necessary results of natural selection in the Struggle for Life,
-namely, the laws of _differentiation_ and _perfecting_, manifest
-themselves everywhere in the development of the larger and smaller
-groups of the natural system of plants. In each larger or smaller period
-of the organic history of the earth, the vegetable kingdom increases
-both in _variety_ and _perfection_, as a glance at Plate IV. will
-clearly show. During the whole of the long primordial period there
-existed only the lowest and most imperfect group, that of the Algae. To
-these are added, in the primary period, the higher and more perfect
-Cryptogamia, especially the main-class of Ferns. During the coal period
-the Phanerogamia begin to develop out of the latter; at first, however,
-they are represented only by the lower main-class, that of Gymnosperms.
-It was not until the secondary period that the higher main-class, that
-of Angiosperms, arose out of them. Of these also there existed at first
-only the lower groups without distinct corollas, the Monocotyledons and
-the Apetalae. It was not until the chalk period that the higher
-Corolliflorae developed out of the latter. But even this most highly
-developed group is represented, in the chalk period, only by the lower
-stage of Star-flowers, or Diapetalae, and only at quite a late date, in
-the tertiary period, did the more highly developed Bell-blossoms,
-Gamopetalae, arise out of them, which at the same time are the most
-perfect of all flowering plants. Thus, in each succeeding later division
-of the organic history of the earth the vegetable kingdom gradually rose
-to a higher degree of perfection and variety.
-
-
-
-
-CHAPTER XVIII.
-
-PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-I. ANIMAL-PLANTS AND WORMS.
-
-
-  The Natural System of the Animal Kingdom.--Linnaeus and Lamarck's
-  Systems.--The Four Types of Baer and Cuvier.--Their Increase to
-  Seven Types.--Genealogical Importance of the Seven Types as
-  Independent Tribes of the Animal Kingdom.--Derivation of
-  Zoophytes and Worms from Primaeval Animals.--Monophyletic and
-  Polyphyletic Hypothesis of the Descent of the Animal
-  Kingdom.--Common Origin of the Four Higher Animal Tribes out of
-  the Worm Tribe.--Division of the Seven Animal Tribes into
-  Sixteen Main Classes, and Thirty-eight Classes.--Primaeval
-  Animals (Monera, Amoebae, Synamoebae), Gregarines, Infusoria,
-  Planaeades, and Gastraeades (Planula and Gastrula).--Tribe of
-  Zoophytes.--Spongiae (Mucous Sponges, Fibrous Sponges, Calcareous
-  Sponges).--Sea Nettles, or Acalephae (Corals, Hood-jellies,
-  Comb-jellies).--Tribe of Worms.
-
-
-The natural system of organisms which we must employ in the animal as
-well as in the vegetable kingdom, as a guide in our genealogical
-investigations, is in both cases of but recent origin, and essentially
-determined by the progress of comparative anatomy and ontogeny (the
-history of individual development) during the present century. Almost
-all the attempts at classification made in the last century followed the
-path of the artificial system, which was first established in a
-consistent manner by Charles Linnaeus. The artificial system differs
-essentially from the natural one, in the fact that it does not make the
-whole organization and the internal structure (depending upon the blood
-relationship) the basis of classification, but only employs individual,
-and for the most part external, characteristics, which readily strike
-the eye. Thus Linnaeus distinguished his twenty-four classes of the
-vegetable kingdom principally by the number, formation, and combination
-of the stamens. In like manner he distinguished six classes in the
-animal kingdom principally by the nature of the heart and blood. These
-six classes were: (1) Mammals; (2) Birds; (3) Amphibious Animals; (4)
-Fishes; (5) Insects; and (6) Worms.
-
-But these six animal classes of Linnaeus are by no means of equal value,
-and it was an important advance when, at the end of the last century,
-Lamarck comprised the first four classes as vertebrate animals
-(Vertebrata), and put them in contrast with the remaining animals (the
-insects and worms of Linnaeus), of which he made a second main
-division--the invertebrate animals (Invertebrata). In reality Lamarck
-thus agreed with Aristotle, the father of Natural History, who had
-distinguished these two main groups, and called the former
-_blood-bearing animals_, the latter _bloodless animals_.
-
-The next important progress towards a natural system of the animal
-kingdom was made some decades later by two most illustrious zoologists,
-Carl Ernst Baer and George Cuvier. As has already been remarked, they
-established, almost simultaneously and independently of one another, the
-proposition that it was necessary to distinguish several completely
-distinct main groups in the animal kingdom, each of which possessed an
-entirely peculiar type or structure (compare above, vol. i. p. 53). In
-each of these main divisions there is a tree-shaped and branching
-gradation from most simple and imperfect forms to those which are
-exceedingly composite and highly developed. The _degree of development_
-within each type is quite independent of the peculiar _plan of
-structure_, which forms the basis of the type and gives it a special
-characteristic. The "type" is determined by the peculiar relations in
-position of the most important parts of the body, and the manner in
-which the organs are connected. The degree of development, however, is
-dependent upon the greater or less division of labour among organs, and
-on the differentiation of the plastids and organs. This extremely
-important and fruitful idea was established by Baer, who relied more
-distinctly and thoroughly upon the history of individual development
-than did Cuvier. Cuvier based his argument upon the results of
-comparative anatomy. But neither of them recognized the true cause of
-the remarkable relationships pointed out by them, which is first
-revealed to us by the Theory of Descent. It shows us that the common
-_type_ or plan of structure is determined by _inheritance_, and the
-degree of development or differentiation by _adaptation_. (Gen. Morph.
-ii. 10).
-
-Both Baer and Cuvier distinguished four different types in the animal
-kingdom, and divided it accordingly into four great main divisions
-(branches or circles). The first of these is formed by the vertebrate
-animals (Vertebrata), and comprises Linnaeus' first four
-classes--mammals, birds, amphibious animals, and fishes. The second type
-is formed by the articulated animals (Articulata), containing Linnaeus'
-insects, consequently the six-legged insects, and also the myriopods,
-spiders, and crustacea, but besides these, a large number of the worms,
-especially the ringed worms. The third main division comprises the
-molluscous animals (Mollusca)--slugs, snails, mussels, and some kindred
-groups. Finally, the fourth and last circle of the animal kingdom
-comprises the various radiated animals (Radiata), which at first sight
-differ from the three preceding types by their radiated, flower-like
-form of body. For while the bodies of molluscs, articulated animals, and
-vertebrated animals consist of two symmetrical lateral halves--of two
-counterparts or antimera, of which the one is the mirror of the
-other--the bodies of the so-called radiated animals are composed of more
-than two, generally of four, five, or six counterparts grouped round a
-common central axis, as in the case of a flower. However striking this
-difference may seem at first, it is, in reality, a very subordinate one,
-and the radial form has by no means the same importance in all "radiated
-animals."
-
-The establishment of these natural main groups or types of the animal
-kingdom by Baer and Cuvier was the greatest advance in the classification
-of animals since the time of Linnaeus. The three groups of vertebrated
-animals, articulated animals, and molluscs are so much in accordance
-with nature that they are retained, even at the present day, little
-altered in extent. But a more accurate knowledge soon showed the utterly
-unnatural character of the group of the radiated animals. Leuckart, in
-1848, first pointed out that two perfectly distinct types were
-confounded under the name, namely, the _Star-fishes_ (Echinoderma)--the
-sea-stars, lily encrinites, sea-urchins, and sea-cucumbers; and, on the
-other hand, the _Animal-plants_, or _Zoophytes_ (Coelenterata or
-Zoophyta)--the sponges, corals, hood-jellies, and comb-jellies. At the
-same time, Siebold united the Infusoria with the Rhizopoda, under the
-name of Protozoa (lowest animals), into a special main division of the
-animal kingdom. By this the number of animal types was increased to six.
-It was finally increased to seven by the fact that modern zoologists
-separated the main division of the articulated animals into two groups:
-(_a_) those possessing _articulated feet_ (Arthropoda), corresponding to
-Linnaeus' Insects, namely, the Flies (with six legs), Myriopods, Spiders,
-and Crustacea; and (_b_) the footless _Worms_ (Vermes), or those
-possessing non-articulated feet. These latter comprise only the real or
-genuine Worms (ring-worms, round worms, planarian worms, etc.), and
-therefore in no way correspond with the Worms of Linnaeus, who had
-included the molluscs, the radiates, and many other lower animals under
-this name.
-
-Thus, according to the views of modern zoologists, which are given in
-all recent manuals and treatises on zoology, the animal kingdom is
-composed of seven completely distinct main divisions or types, each of
-which is distinguished by a characteristic plan of structure peculiar to
-it, and perfectly distinct from every one of the others. In the natural
-system of the animal kingdom--which I shall now proceed to explain as
-its probable pedigree--I shall on the whole agree with this usual
-division, but not without some modifications, which I consider very
-important in connection with genealogy, and which are rendered
-absolutely necessary in consequence of our view as to the history of the
-development of animals.
-
-We evidently obtain the greatest amount of information concerning the
-_pedigree of the animal kingdom_ (as well as concerning that of the
-vegetable kingdom) from comparative anatomy and ontogeny. Besides
-these, palaeontology also throws much valuable light upon the historical
-succession of many of the groups. From numerous facts in comparative
-anatomy, we may, in the first place, infer the _common origin of all
-those animals which belong to one of the seven "types."_ For in spite of
-all the variety in the external form developed within each of these
-types, the essential relative position of the parts of the body which
-determines the type, is so constant, and agrees so completely in all the
-members of every type, that on account of their relations of form alone
-we are obliged to unite them, in the natural system, into a single main
-group. But we must certainly conclude, moreover, that this conjunction
-also has its expression in the pedigree of the animal kingdom. For the
-true cause of the intimate agreement in structure can only be the actual
-blood relationship. Hence we may, without further discussion, lay down
-the important proposition that all animals belonging to one and the same
-circle or type must be descended from one and the same original primary
-form. In other words, the idea of the circle or type, as it is employed
-in zoology since Baer and Cuvier's time to designate the few principal
-main groups or "sub-kingdoms" of the animal kingdoms, coincides with the
-idea of "tribe" or "phylum," as employed by the Theory of Descent.
-
-If, then, we can trace all the varieties of animal forms to these seven
-fundamental forms, the following question next presents itself to us as
-a second phylogenetic problem--Where do these seven animal tribes come
-from? Are they seven original primary forms of an entirely independent
-origin, or are they also distantly related by blood to one another?
-
-[Illustration: _PL. VI._
-
-Historical Growth of the six great stems of Animals. _See the
-Explanation._]
-
-At first we might be inclined to answer this question in a
-_polyphyletic_ sense, by saying that we must assume, for each of the
-seven great animal tribes, at least one independent primary form
-completely distinct from the others. On further considering this
-difficult problem, we arrive in the end at the notion of a
-_monophyletic_ origin of the animal kingdom, viz., that these seven
-primary forms are connected at their lowest roots, and that they are
-derived from a single, common primaeval form. _In the animal as well as
-in the vegetable kingdom, when closely and accurately considered, the
-monophyletic hypothesis of descent is found to be more satisfactory than
-the polyphyletic hypothesis._
-
-It is _comparative ontogeny_ (embryology) which first and foremost leads
-to the assumption of the monophyletic origin of the whole animal kingdom
-(the Protista excepted of course). The zoologist who has thoughtfully
-compared the history of the individual development of various animals,
-and has understood the importance of the biogenetic principle (p. 33),
-cannot but be convinced that a common root must be assumed for the seven
-different animal tribes, and that all animals, including man, are
-derived from a single, common primary form. The result of the
-consideration of the facts of embryology, or ontogeny, is the following
-genealogical or phylogenetic hypothesis, which I have put forward and
-explained in detail in my "Philosophy of Calcareous Sponges" (Monograph
-of the Calcareous Sponges, vol. i. pp. 464, 465, etc.,--"the Theory of
-the Layers of the Embryo, and the Pedigree of Animals").
-
-The first stage of organic life in the Animal kingdom (as in the
-Vegetable and Protista kingdoms) was formed by perfectly simple
-_Monera_, originating by spontaneous generation. The former existence
-of this simplest animal form is, even at present, attested by the fact
-that the egg-cell of many animals loses its kernel directly after
-becoming fructified, and thus relapses to the lower stage of development
-of a cytod without a kernel, like a Moneron. This remarkable occurrence
-I have interpreted, according to the law of latent inheritance (vol. i.
-p. 205), as a phylogenetic _relapse_ of the cellular form into the
-original form of a cytod. The _Monerula_, as we may call this egg-cytod
-without a kernel, repeats then, according to the biogenetic principle
-(vol. ii. p. 33), the most ancient of all animal forms, the common
-primary form of the animal kingdom, namely, the Moneron.
-
-The second ontogenetic process consists in a new kernel being formed in
-the Monerula, or egg-cytod, which thus returns again to the value of a
-true _egg-cell_. According to this, we must look upon the simple animal
-cell, containing a kernel, or the single-celled primaeval animal--which
-may still be seen in a living state in the _Amoebae_ of the present
-day--as the _second_ step in the series of phylogenetic forms of the
-animal kingdom. Like the still living simple Amoebae, and like the naked
-egg-cells of many lower animals (for example, of Sponges and Medusae,
-etc.), which cannot be distinguished from them, the remote phyletic
-primary Amoebae also were perfectly simple naked-cells, which moved about
-in the Laurentian primaeval ocean, creeping by means of the ever-changing
-processes of their body-substance, and nourishing and propagating
-themselves in the same way as the Amoebae of the present day. (Compare
-vol. i. p. 188, and vol. ii. p. 54.) The existence of this Amoeba-like,
-_single-celled primary form_ of the whole animal kingdom is unmistakably
-indicated by the exceedingly important fact that the egg of all animals,
-from those of sponges and worms up to those of the ant and man, is a
-simple cell.
-
-Thirdly, from the "single-cell" state arose the _simplest multicellular
-state_, namely, a heap or a small community of simple, equi-formal, and
-equivalent cells. Even at the present day, in the ontogenetic
-development of every animal egg-cell, there first arises a globular heap
-of equi-formal naked cells, by the repeated self-division of the primary
-cell. (Compare vol. i. p. 190 and the Frontispiece, Fig. 3.) We called
-this accumulation of cells the _mulberry state_ (Morula), because it
-resembles a mulberry or blackberry. This Morula-body occurs in the same
-simple form in all the different tribes of animals, and on account of
-this most important circumstance we may infer--according to the
-biogenetic principle--that the _most ancient, many-celled, primary form
-of the animal kingdom_ resembled a Morula like this, and was in fact a
-simple heap of Amoeba-like primaeval cells, one similar to the other. We
-shall call this most ancient community of Amoebae--this most simple
-accumulation of animal cells--which is recapitulated in individual
-development by the Morula--the _Synamoeba_.
-
-Out of the Synamoebae, in the early Laurentian period, there afterwards
-developed a fourth primary form of the animal kingdom, which we shall
-call the ciliated germ (Planaea). This arose out of the Synamoeba by the
-outer cells on the surface of the cellular community beginning to extend
-vibrating fringes called cilia, and becoming "ciliated cells," and thus
-differentiating from the inner and unchanged cells. The Synamoebae
-consisted of completely equi-formed and naked cells, and crept about
-slowly, at the bottom of the Laurentian primaeval ocean, by means of
-movements like those of an Amoeba. The Planaea, on the other hand,
-consisted of two kinds of different cells--inner ones like the Amoebae,
-and external "ciliated cells." By the vibrating movements of the cilia
-the entire multicellular body acquired a more rapid and stronger motion,
-and passed over from the creeping to the swimming mode of locomotion. In
-exactly the same manner the _Morula_, in the ontogenesis of lower
-animals, still changes into a ciliated form of larva, which has been
-known, since the year 1847, under the name of _Planula_. This Planula is
-sometimes a globular, sometimes an oval body, which swims about in the
-water by means of a vibrating movement; the fringed (ciliated) and
-smaller cells of the surface differ from the larger inner cells, which
-are unfringed. (Fig. 4 of the Frontispiece.)
-
-Out of this Planula, or fringed larva, there then develops, in animals
-of all tribes, an exceedingly important and interesting animal form,
-which, in my Monograph of the Calcareous Sponges, I have named
-_Gastrula_ (that is, larva with a stomach or intestine). (Frontispiece,
-Fig. 5, 6). This Gastrula externally resembles the Planula, but differs
-essentially from it in the fact that it encloses a cavity which opens to
-the outside by a mouth. The cavity is the "_primary intestine_," or
-"primary stomach," the _progaster_, the first beginning of the
-alimentary canal; its opening is the "_primary mouth_" (prostoma). The
-wall of the progaster consists of two layers of cells: an outer layer of
-smaller ciliated cells (outer skin, or ectoderm), and of an inner layer
-of larger non-ciliated cells (inner skin, or entoderm). This exceedingly
-important larval form, the "Gastrula," makes its appearance in the
-ontogenesis of all tribes of animals--in Sponges, Medusae, Corals, Worms,
-Sea-squirts, Radiated animals, Molluscs, and even in the lowest
-Vertebrata (Amphioxus: compare p. 200, Plate XII., Fig. _B_ 4; see also
-in the same place the Ascidian, Fig. _A_ 4).
-
-
-  Definition of the _forms_      |   +Ontogenesis.+             |    +Phylogenesis.+
-  of the five first stages       | The five first stages        | The five first stages
-  of the development of          | of the individual            | of the phyletic or
-  the animal body.               | development.                 | historical development.
-  -------------------------------+------------------------------+------------------------
-                                 |                              |
-  _First Stage of Development._  |             1.               |          1.
-                                 |         +Monerula.+          |       +Moneron.+
-  A simple cytod (a              |                              |
-  plastid without a kernel.)     | Animal egg without a         | Most ancient animal
-             |                   | kernel (when the egg-kernel  | Monera, originating by
-             |                   | has disappeared,             | spontaneous generation.
-             |                   | after being fructified).     |          |
-             |                   |             |                |          |
-             |                   |             |                |          |
-  _Second Stage of Development._ |             2.               |          2.
-                                 |          +Ovulum.+           |       +Amoebae.+
-  A simple cell (a               |                              |
-  plastid containing a           | Animal egg with kernel       | Animal Amoebae.
-  kernel.)                       | (a simple egg-cell).         |          |
-              |                  |             |                |          |
-              |                  |             |                |          |
-              |                  |             |                |          |
-  _Third Stage of Development._  |             3.               |          3.
-                                 |          +Morula.+           |     +Synamoeba.+
-  A community (an                |     (_Mulberry form._)       |
-  aggregation of identical       |                              | An aggregation of
-  simple cells).                 | Globular heap of homogeneous | Amoebae.
-              |                  | "cleavage spheres."          |          |
-              |                  |             |                |          |
-              |                  |             |                |          |
-  _Fourth Stage of Development._ |             4.               |          4.
-                                 |          +Planula.+          |       +Planaea.+
-  A solid or bladder-shaped,     |     (_Ciliated larva_.)      |
-  globular, or oval              |                              | Many-celled primaeval
-  body, _composed of two         | Many-celled larva            | animal without
-  kinds of different cells_:     | without mouth, composed      | mouth, composed of
-  externally ciliated,           | of different cells.          | two kinds of different
-  internally non-ciliated        |             |                | cells.
-  cells.                         |             |                |          |
-              |                  |             |                |          |
-              |                  |             |                |          |
-  _Fifth Stage of Development._  |             5.               |          5.
-                                 |          +Gastrula.+         |       +Gastraea.+
-  A globular or oval             |     (_Larva with mouth._)    |
-  _body with simple intestinal   | Many-celled with intestines  | Many-celled primaeval
-  cavity and mouth-opening.      | and mouth; intestinal        | animal with intestine
-  Body wall composed             | wall with two                | and mouth; intestinal
-  of two layers_; an             | layers.                      | wall with two
-  externally ciliated ectoderm   |                              | layers. (Primary form
-  (dermal layer), an             |                              | of zoophytes and
-  internally non-ciliated        |                              | worms.)
-  entoderm (gastral layer).      |                              |
-
-
-From the ontogenetic occurrence of the Gastrula in the most different
-animal classes, from Zoophytes up to Vertebrata, we may, according to
-the biogenetic principle, safely draw the conclusion that during the
-Laurentian period there existed a common primary form of the six higher
-animal tribes, which in all essential points was formed like the
-Gastrula, and which we shall call the Gastraea. This Gastraea possessed a
-perfectly simple globular or oval body, which enclosed a simple cavity
-of like form, namely, the progaster; at one of the poles of the
-longitudinal axis the primary intestine opened by a mouth which served
-for the reception of nutrition. The body wall (which was also the
-intestinal wall) consisted of two layers of cells, the unfringed
-entoderm, or intestinal layer, and the fringed ectoderm, or skin-layer;
-by the motion of the cilia or fringes of the latter the Gastraea swam
-about freely in the Laurentian ocean. Even in those higher animals, in
-the ontogenesis of which the original Gastrula form has disappeared,
-according to the laws of abbreviated inheritance (vol. i. p. 212), the
-composition of the Gastraea body has been transmitted to the phase of
-development which directly arises out of the Morula. This phase is an
-oval or round disc consisting of two cell-layers or membranes: the outer
-cell-layer, the _animal or dermal layer_ (ectoblast), corresponds to the
-ectoderm of the Gastraea; out of it develops the external, loose skin
-(epidermis), with its glands and appendages, as well as the central
-nervous system. The inner cell-layer, the _vegetative or intestinal
-layer_ (hypoblast), is originally the entoderm of the Gastraea; out of it
-develops the inner membrane (epithelium) of the intestinal canal and its
-glands. (Compare my Monograph of the Calcareous Sponges, vol. i. p. 466,
-etc.)
-
-By ontogeny we have already gained five primordial stages of development
-of the animal kingdom: (1) the Moneron; (2) the Amoeba; (3) the
-Synamoeba; (4) the Planaea; and (5) the Gastraea. The former existence of
-these five oldest primary forms, which succeeded one another, and which
-must have lived in the Laurentian period, follows as a consequence of
-the biogenetic principle; that is to say, from the parallelism and the
-mechanico-causal connection of ontogenesis and phylogenesis. (Compare
-vol. i. p. 309.) In our genealogical system of the animal kingdom we may
-class all these animal forms, long since extinct, and, which on account
-of the soft nature of their bodies could leave no fossil remains, among
-the tribe of Primaeval animals (Protozoa), which also comprises the still
-living Infusoria and Gregarinae.
-
-The phyletic development of the six higher animal tribes, which are all
-derived from the Gastraea, deviated at this point in two directions. In
-other words, the _Gastraeads_ (as we may call the group of forms
-characterized by the Gastraea-type of structure), divided into two
-divergent lines or branches; the one branch of Gastraeads gave up free
-locomotion, adhered to the bottom of the sea, and thus, by adopting an
-adhesive mode of life, gave rise to the _Protascus_, the common primary
-form of the _Animal-plants_ (Zoophyta). The other branch of the
-Gastraeads retained free locomotion, did not become adherent and later
-on developed into the _Prothelmis_, the common primary form of _Worms_
-(Vermes). (Compare p. 133.)
-
-This latter tribe (as limited by modern zoology) is of the greatest
-interest in the study of genealogy. For among Worms, as we shall see
-later, there are, besides very numerous peculiar families, and besides
-many independent classes, also very remarkable forms, which may be
-considered as _forms of direct transition_ to the four higher animal
-tribes. Both comparative anatomy and the ontogeny of these worms enable
-us to recognize in them the nearest blood relations of those extinct
-animal forms which were the original primary forms of the four higher
-animal tribes. Hence these latter, the Molluscs, Star-fishes,
-Articulated animals, and Vertebrate animals, do not stand in any close
-blood relationship to one another, but have originated independently in
-four different places out of the tribe of Worms.
-
-In this way comparative anatomy and phylogeny lead us to the
-_monophyletic pedigree of the animal kingdom_, the outlines of which are
-given on p. 133. According to it the seven phyla, or tribes, of the
-animal kingdom are of different value in regard to genealogy. The
-original primary group of the whole animal kingdom is formed by the
-Primaeval animals (Protozoa), including the Infusoria and Gastraeads. Out
-of these latter arose the two tribes of Animal-plants (Zoophyta) and
-Worms as diverging branches. Out of four different groups of the Worm
-tribe, the four higher tribes of the animal kingdom were developed--the
-Star-fishes (Echinoderma) and Insects (Arthropoda) on the one hand, and
-the Molluscs (Mollusca) and Vertebrated animals (Vertebrata) on the
-other.
-
-Having thus sketched out the monophyletic pedigree of the animal kingdom
-in its most important features, we must now turn to a closer examination
-of the historical course of development which the seven tribes of the
-animal kingdom, and the classes distinguished in them, have passed
-through (p. 132). There is a much larger number of classes in the animal
-than in the vegetable kingdom, owing to the simple reason that the
-animal body, in consequence of its more varied and perfect vital
-activity, could differentiate and develop in very many more different
-directions than could the vegetable body. Thus, while we were able to
-divide the whole vegetable kingdom into six main classes and nineteen
-classes, we have to distinguish, at least, sixteen main classes and
-thirty-eight classes in the animal kingdom. These are distributed among
-the seven different tribes of the animal kingdom in the way shown in the
-Systematic Survey on pages 132 and 133.
-
-The group of _Primaeval animals_ (Protozoa) within the compass which we
-here assign to this tribe, comprises the most ancient and the simplest
-primary forms of the animal kingdom; for example, the five oldest
-phyletic stages of development previously mentioned, and besides these
-the Infusoria and Gregarinae, as well as all those imperfect animal
-forms, for which, on account of their simple and indifferent
-organization, no place can be found in any of the other six animal
-tribes. Most zoologists, in addition to these, include among the
-Protozoa a larger or smaller portion of those lowest organisms, which we
-mentioned in our neutral kingdom of Protista (in Chapter XVI.). But
-these Protista, especially the large division of the Rhizopoda, which
-are so rich in forms, cannot be considered as real animals for reasons
-previously given. Hence, if we here leave them out of the question, we
-may accept two main classes or provinces of real Protozoa, namely, _Egg
-animals_ (Ovularia) and _Germ animals_ (Blastularia). To the former
-belong the three classes of Archezoa, Gregarinae, and Infusoria, to the
-latter the two classes of Planaeads and Gastraeads.
-
-SYSTEMATIC SURVEY
-
-_Of the 16 Main Classes and 38 Classes of the Animal Kingdom._
-
-
-  ------------------+-----------------------+----------------------+-----------------
-  _Tribes or Phyla_ |  _Main Classes_,      |    _Classes_         |_Systematic Name_
-      _of the_      |_Branches or Clades_   |     _of the_         |    _of the_
-  _Animal Kingdom._ |    _of the_           |  _Animal Kingdom._   |   _Classes._
-                    | _Animal Kingdom._     |                      |
-  ------------------+-----------------------+----------------------+------------------
-
-          A.        {
-       =Primaeval=   { I. Egg-animals         { 1. Archaic animals     1. Archezoa
-       =Animals=    {    _Ovularia_          { 2. Gregarines          2. Gregarinae
-                    {                        { 3. Infusoria           3. Infusoria
-      +Protozoa+    {
-                    {II. Mulberry animals    { 4. Planaeads            4. Planaeadas
-                    {    _Blastularia_       { 5. Gastraeads           5. Gastraeadas
-
-
-          B.        {
-        =Animal=    {   III. Sponges         { 6. Sponges             6. Porifera
-        =Plants=    {      _Spongiae_         {
-                    {
-      +Zoophyta+    {  IV. Sea-nettles       { 7. Corals              7. Coralla
-                    {      _Acalephae_        { 8. Hood-jellies        8. Hydromedusae
-                    {                        { 9. Comb-jellies        9. Ctenophora
-
-
-          C.        {V. Bloodless worms      {10. Planary worms      10. Platyhelminthes
-        =Worms=     {   _Acoelomi_
-                    {                        {11. Round worms        11. Nemathelminthes
-      +Vermes+      {  VI. Blood-bearing     {12. Moss-polyps        12. Bryozoa
-                    {        worms           {13. Sac-worms          13. Tunicata
-                    {      _Coelomati_       {14. Proboscideans      14. Rhynchocoela
-                    {                        {15. Star-worms         15. Gephyrea
-                    {                        {16. Wheel animalcules  16. Rotatoria
-                    {                        {17. Ring-worms         17. Annelida
-
-
-          D.        {VII. Headless shellfish {18. Lamp-shells        18. Spirobranchia
-       =Molluscs=   {     _Acephala_         {19. Mussels            19. Lamellibranchia
-                    {
-      +Mollusca+    {  VIII. Head-bearing    {20. Snails             20. Cochlides
-                    {       _Eucephala_      {21. Cuttles            21. Cephalopoda
-
-
-          E.        {  IX. Ringed-arms       {22. Sea-stars          22. Asterida
-      =Star-fishes= {    _Colobrachia_       {23. Lily-stars         23. Crinoida
-                    {
-     +Echinoderma+  {      X. Armless        {24. Sea-urchins        24. Echinida
-                    {      _Lipobrachia_     {25. Sea-cucumbers      25. Holothuriae
-
-
-          F.        {  XI. Gill-breathers    {26. Crab-fish          26. Crustacea
-      =Articulated= {       _Carides_        {
-        =Animals=   {
-                    {  XII. Tube-breathers   {27. Spiders            27. Arachnida
-      +Arthropoda+  {       _Tracheata_      {28. Centipedes         28. Myriopoda
-                    {                        {29. Flies              29. Insecta
-
-
-                    {   XIII. Skull-less     {30. Lancelets          30. Leptocardia
-                    {        _Acrania_       {
-          G.        {
-      =Vertebrate=  { XIV. Single-nostriled  {31. Lampreys           31. Cyclostoma
-       =Animals=    {    _Monorrhina_        {
-                    {
-     +Vertebrata+   {   XV. Amnion-less      {32. Fishes             32. Pisces
-                    {      _Anamnia_         {33. Mud-fish           33. Dipneusta
-                    {                        {34. Sea dragons        34. Halisauria
-                    {                        {35. Amphibians         35. Amphibia
-                    {
-                    { XVI. Amnion-bearing    {36. Reptiles           36. Reptilia
-                    {      _Amniota_         {37. Birds              37. Aves
-                    {                        {38. Mammals            38. Mammalia
-
-        ----------------------------------------------------------------
-
-                                         +Vertebrata+
-                                      (_Vertebrated animals_)
-                                           Craniota
-                                              |
-                       +Arthropoda+           |               +Mollusca+
-                  (_Articulated Animals_)     |              (_Molluscs_)
-  +Echinoderma+          Tracheata            |               Eucephala
-  (_Star-fishes_)           |                 |                   |
-                            |                 |                   |
-  Lipobrachia          Crustacea           Acrania                |
-       |      Annelida      |                 |  Tunicata     Acephala
-       |         |          |                 |      |  Bryozoa   |
-  Colobrachia    |          |                 |      |     |      |
-       | Gephyrea|          |   Rotatoria     \--v---/     \--v---/
-       |     |   |          |       |            |            |
-       |     |   |          |       |            |            |
-       \---------v-------------------/           \------v-----/
-                 |                                      |
-                 |               +Vermes+               |
-                 |              (_Worms_)               |
-                 \------------------v-------------------/
-                                    |
-                                    |
-                                 COELOMATI
-                      (_Worms with a body-cavity_)
-                                  |     Platyhelminthes
-                                  |            |
-                                  |            |
-                                  \-----v------/
-     +Zoophyta+                         |
-  (_Animal-Plants_)                 +ACOELOMI+
-  Spongiae        Acalephae   (_Worms without body-cavity_)
-     |              |                   |
-     |              |                   |
-     \------v-------/                   |
-            |                           |
-        Protascus                   Prothelmis
-            |                           |
-            |                           |
-            \-----------v---------------/
-                        |
-                        |          +Protozoa+
-                        |      (_Primaeval animals_)
-                        |
-                        |/-------------^-------------\
-                     +GASTRAEA+
-                        |
-                        |         Infusoria
-                        |             |
-                     +PLANAEA+         |     Gregarinae
-                        |             |        |
-                        |             |        |
-                   +SYNAMOEBAE+         \----v---/
-                        |                  |
-                        |                  |
-                        \---------v--------/
-                               +AMOEBAE+
-                                  |
-                               +MONERA+
-
-
-The first province of the Protozoa consists of the _Egg animals_
-(Ovularia); we include among them all _single-celled animals_, all
-animals whose body, in the fully developed state, possesses the
-form-value of a _simple plastid_ (of a cytod or a cell), also those
-simple animal forms whose body consists of an aggregation of several
-cells perfectly similar one to another.
-
-The _Archaic animals_ (Archezoa) form the first class in the series of
-Egg animals. It contains only the most simple and most ancient primary
-forms of the animal kingdom, whose former existence we have proved by
-means of the fundamental law of biogenesis; they are, (1) Animal Monera;
-(2) Animal Amoebae; (3) Animal Synamoebae. We may, if we choose, include
-among them a portion of the still living Monera and Amoebae, but another
-portion (according to the discussion in Chapter XVI.) must on account of
-their neutral nature be considered as Protista, and a third portion, on
-account of their vegetable nature, must be considered as plants.
-
-A second class of the egg animals consists of the _Gregarines_
-(Gregarinae), which live as parasites in the intestines and body-cavities
-of many animals. Some of these Gregarines are perfectly simple cells
-like the Amoebae; some form chains of two or three identical cells, one
-lying behind the other. They differ from the naked Amoebae by possessing
-a thick, simple membrane, which surrounds their cell-body; they can be
-considered as animal Amoebae which have adopted a parasitical mode of
-life, and in consequence have surrounded themselves with a secreted
-covering.
-
-As a third class of egg animals, we adopt the real _Infusoria_
-(Infusoria), embracing those forms to which modern zoology almost
-universally limits this class of animals. The principal portion of them
-consists of the small _ciliated Infusoria_ (Ciliata), which inhabit all
-the fresh and salt waters of the earth in great numbers, and which swim
-about by means of a delicate garb of vibratile fringes. A second and
-smaller division consists of the adherent _sucking Infusoria_ (Acinetae),
-which take their food by means of fine sucking-tubes. Although during
-the last thirty years numerous and very careful investigations have been
-made on these small animalcules,--which are mostly invisible to the
-naked eye,--still we are even now not very sure about their development
-and form-value. We do not even yet know whether the Infusoria are single
-or many-celled; but as no investigator has as yet proved their body to
-be a combination of cells, we are, in the mean time, justified in
-considering them as single-celled, like the Gregarines and the Amoebae.
-
-The second main class of primaeval animals consists of the _Germ animals_
-(Blastularia). This name we give to those extinct Protozoa which
-correspond to the two ontogenetic embryonic forms of the six higher
-animal tribes, namely, the Planula and the Gastrula. The body of these
-Blastularia, in a perfectly developed state, was composed of many cells,
-and these cells moreover differentiated--in two ways at least--into an
-external (animal or dermal) and an internal (vegetative or gastral)
-mass. Whether there still exist representatives of this group is
-uncertain. Their former existence is undoubtedly proved by the two
-exceedingly important ontogenetic animal forms which we have already
-described as Planula and Gastrula, and which still occur as a transient
-stage of development in the ontogeny of the most different tribes of
-animals. Corresponding to these, we may, according to the biogenetic
-principle, assume the former existence of two distinct classes of
-Blastularia, namely, the _Planaeada_ and _Gastraeada_. The type of the
-_Planaeada_ is the _Planaea_--long since extinct--but whose historical
-portrait is still presented to us at the present day in the widely
-distributed _ciliated larva_ (Planula). (Frontispiece, Fig. 4.) The type
-of the _Gastraeada_ is the _Gastraea_, of whose original nature the
-mouth-and-stomach larva (Gastrula), which recurs in the most different
-animal tribes, still gives a faithful representation. (Frontispiece Fig.
-5, 6.) Out of the Gastraea, as we have previously mentioned, there were
-at one time developed two different primary forms, the Protascus and
-Prothelmis; the former must be looked upon as the primary form of the
-Zoophytes, the latter as the primary form of Worms. (Compare the
-enunciation of this hypothesis in my Monograph of the Calcareous
-Sponges, vol i. p. 464.)
-
-The _Animal-plants_ (Zoophyta, or Coelenterata) which constitute the
-second tribe of the animal kingdom, rise considerably above the
-primitive animals in the characters of their whole organisation, while
-they remain far below most of the higher animals. For in the latter
-(with the exception only of the lowest forms) the four distinct
-functions of nutrition--namely, digestion, circulation of the blood,
-respiration, and excretion--are universally accomplished by four
-perfectly different systems of organs: by the intestines, the vascular
-system, the organs of respiration, and the urinary apparatus. In
-Zoophytes, however, these functions and their organs are not yet
-separate, and are all performed by a single system of alimentary canals,
-by the so-called gastro-vascular system, or the coelenteric apparatus of
-the intestinal cavity. The mouth, which is also the anus, leads into a
-stomach, into which the other cavities of the body also open. In
-Zoophytes the body-cavity, or "coeloma," possessed by the four higher
-tribes of animals is still completely wanting, likewise the vascular
-system and blood, as also the organs of respiration, etc.
-
-All Zoophytes live in water; most of them in the sea, only a very few in
-fresh water, such as fresh-water sponges (Spongilla) and some primaeval
-polyps (Hydra, Cordylophora). A specimen of the pretty flower-like forms
-which are met with in great variety among Zoophytes is given on Plate
-VII. (Compare its explanation in the Appendix.)
-
-The tribe of animal-plants, or Zoophytes, is divided into two distinct
-provinces, the _Sponges_, or _Spongiae_, and the _Sea-nettles_, or
-_Acalephae_ (p. 144). The latter are much richer in forms and more highly
-organized than the former. In all Sponges the entire body, as well as
-the individual organs, are differentiated and perfected to a much less
-extent than in Sea-nettles. All Sponges lack the characteristic
-_nettle-organs_ which all Sea-nettles possess.
-
-The common primary form of all Zoophytes must be looked for in the
-_Protascus_, an animal form long since extinct, but whose existence is
-proved according to the biogenetic principle by the Ascula. This Ascula
-is an ontogenetical development form which, in Sponges as well as in
-Sea-nettles, proceeds from the Gastrula. (Compare the Ascula of the
-calcareous sponge on the Frontispiece, Fig. 7, 8.) For after the
-Gastrula of zoophytes has for a time swum about in the water it sinks to
-the bottom, and there adheres by that pole of its axis which is opposite
-to the opening of the mouth. The external cells of the ectoderm draw in
-their vibrating, ciliary hairs, whereas, on the contrary, the inner
-cells of the entoderm begin to form them. Thus the Ascula, as we call
-this changed form of larva, is a simple sack, its cavity (the cavity of
-the stomach or intestine) opening by a mouth externally, at the upper
-pole of the longitudinal axis (opposite the basal point of fixture). The
-entire body is here in a certain sense a mere stomach or intestinal
-canal, as in the case of the Gastrula. The wall of the sack, which is
-both body wall and intestinal wall, consists of two layers or coats of
-cells, a fringed _entoderm_, or gastral layer (corresponding with the
-inner or vegetative germ-layer of the higher animals), and an unfringed
-exoderm or dermal layer (corresponding with the external or animal
-germ-layer of the higher animals). The original _Protascus_, a true
-likeness of which is still furnished by the Ascula, probably formed
-egg-cells and sperm-cells out of its gastral layer.
-
-The Protascads--as we will call the most ancient group of vegetable
-animals, represented by the Protascus-type--divided into two lines or
-branches, the Spongiae and the Sea-nettles, or Acalephae. I have shown in
-my Monograph of the Calcareous Sponges (vol. i. p. 485) how closely
-these two main classes of Zoophytes are related, and how they must both
-be derived, as two diverging forms, from the Protascus-form. The primary
-form of Spongiae, which I have there called Archispongia, arose out of
-the Protascus by the formation of pores through its body-wall; the
-primary form of Sea-nettles, which I there called Archydra, developed
-out of the Protascus by the formation of nettle-organs, as also by the
-formation of feelers or tentacles.
-
-The main-class or branch of the _Sponges_, _Spongiae_, or _Porifera_,
-lives in the sea, with the single exception of the green fresh-water
-Sponge (Spongilla). These animals were long considered as plants, later
-as Protista; in most Manuals they are still classed among the primaeval
-animals, or Protozoa. But since I have demonstrated their development
-out of the Gastrula, and the construction of their bodies of two
-cellular germ-layers (as in all higher animals), their close
-relationship to Sea-nettles, and especially to the Hydrapolyps, seems
-finally to be established. The _Olynthus_ especially, which I consider
-as the common primary form of calcareous sponges, has thrown a complete
-and unmistakable light upon this point.
-
-The numerous forms comprised in the class of Spongiae have as yet been
-but little examined; they may be divided into three legions and eight
-orders. The first legion consists of the soft, gelatinous _Mucous
-Sponges_ (Myxospongiae), which are characterized by the absence of any
-hard skeleton. Among them are, on the one hand, the long-since-extinct
-primary forms of the whole class, the type of which I consider to be the
-Archispongia; on the other hand there are the still living, gelatinous
-sponges, of which the _Halisarca_ is best known. We can obtain a notion
-of the Archispongia, the most ancient primaeval sponge, if we imagine the
-Olynthus (see Frontispiece), to be deprived of its radiating calcareous
-spiculae.
-
-The second legion of Spongiae contains the _Fibrous Sponges_
-(Fibrospongiae), the soft body of which is supported by a firm, fibrous
-skeleton. This fibrous skeleton often consists merely of so-called
-"horny fibres," formed of a very elastic, not readily destructible,
-organic substance. This is the case for instance in our common bathing
-Sponge (Euspongia officinalis), the purified skeleton of which we use
-every morning when washing. Blended with the horny, fibrous skeleton of
-many of these Sponges, there are numerous flinty spicula; this is the
-case for example with the fresh-water Sponge (Spongilla). In others the
-whole skeleton consists of only calcareous or silicious spicula which
-are frequently interwoven into an extremely beautiful lattice-work, as
-in the celebrated Venus' Flower Basket (Euplectella). Three orders of
-fibrous sponges may be distinguished according to the different
-formation of the spicula, namely, Chalynthina, Geodina, and
-Hexactinella. The natural history of the fibrous sponges is of especial
-interest to the Theory of Descent, as was first shown by Oscar Schmidt,
-the greatest authority on this group of animals. In no other group,
-perhaps, can the unlimited pliability of the specific form, and its
-relation to Adaptation and Inheritance, be so clearly followed step by
-step; perhaps in no other group is the species so difficult to limit and
-define.
-
-[Illustration: Pl. VII.
-
-E. Haeckel del. Lagesse sc.]
-
-This proposition, which applies to the great legion of the Fibrous
-Sponges, applies in a still higher degree to the smaller but exceedingly
-interesting legion of the calcareous sponges (Calcispongiae), on which in
-1872, after five years' careful examination, I published a comprehensive
-Monograph. The sixty plates of figures accompanying this Monograph
-explain the extreme pliability of these small sponges "good species" of
-which, in fact, cannot be spoken of in the usual systematic sense. We
-find among them only varying series of forms, which do not even
-completely transmit their specific form to their nearest descendants,
-but by adaptation to subordinate, external conditions of existence,
-perpetually change. It frequently occurs here, that there arise out of
-one and the same stock different form-species, which according to the
-usual system would belong to several quite distinct genera; this is the
-case, for instance, with the remarkable Ascometra (Frontispiece, Fig.
-10.) The entire external bodily form is much more pliable and protean in
-Calcareous Sponges than in the silicious sponges, which are
-characterized by possessing silicious spicula, forming a beautiful
-skeleton. Through the study of the comparative anatomy and ontogeny of
-calcareous sponges, we can recognise, with the greatest certainty, the
-common primary form of the whole group, namely, the sack-shaped
-_Olynthus_, whose development is represented in the Frontispiece
-(compare its explanation in the Appendix). Out of the Olynthus (Fig. 9
-on the Frontispiece), the order of the Ascones was the first to develop,
-out of which, at a later period, the two other orders of Calcareous
-Sponges, the _Leucones_ and _Sycones_, arose as diverging branches.
-Within these orders, the descent of the individual forms can again be
-followed step by step. Thus the Calcareous Sponges in every respect
-confirm the proposition which I have elsewhere maintained: that "the
-natural history of sponges forms a connected and striking argument in
-favour of Darwin."
-
-The second main class or branch in the tribe of Zoophytes is formed by
-the Sea-nettles (Acalephae, or Cnidae). This interesting group of animals,
-so rich in forms, is composed of three different classes, namely, the
-Hood-jellies (Hydromedusae), the Comb-jellies (Ctenophora), and the
-Corals (Coralla). The hypothetical, extinct Archydra must be looked upon
-as the common primary form of the whole group; it has left two near
-relations in the still living fresh-water polyps (Hydra and
-Cordylophora). The Archydra was very closely related to the simplest
-forms of Spongiae (Archispongia and Olynthus), and probably differed from
-them only by possessing nettle organs, and by the absence of cutaneous
-pores. Out of the Archydra there first developed the different Hydroid
-polyps, some of which became the primary forms of Corals, others the
-primary forms of Hydromedusae. The Ctenophora developed later out of a
-branch of the latter.
-
-The Sea-nettles differ from the Spongiae (with which they agree in the
-characteristic formation of the system of the alimentary canal)
-principally by the constant possession of nettle organs. These are small
-bladders filled with poison, large numbers--generally millions--of which
-are dispersed over the skin of the sea nettles, and which burst and
-empty their contents when touched. Small animals are killed by this; in
-larger animals this nettle poison causes a slight inflammation of the
-skin, just as does the poison of our common nettles. Any one who has
-often bathed in the sea, will probably have at times come in contact
-with large Hood-jellies (Jelly-fish), and become acquainted with the
-unpleasant burning feeling which their nettle organs can produce. The
-poison in the splendid blue Jelly-fish, Physalia, or Portuguese
-Man-of-war, acts so powerfully that it may lead to the death of a human
-being.
-
-The class of Corals (Coralla) lives exclusively in the sea, and is more
-especially represented in the warm seas by an abundance of beautiful and
-highly-coloured forms like flowers. Hence they are also called
-_Flower-animals_ (Anthozoa). Most of them are attached to the bottom of
-the sea, and contain an internal calcareous skeleton. Many of them by
-continued growth produce such immense stocks that their calcareous
-skeletons have formed the foundation of whole islands, as is the case
-with the celebrated coral reefs and atolls of the South Seas, the
-remarkable forms of which were first explained by Darwin.(13) In corals
-the counterparts, or antimera--that is, the corresponding divisions of
-the body which radiate from and surround the central main axis of the
-body--exist sometimes to the number of four, sometimes to the number of
-six or eight. According to this we distinguish three legions, the
-Fourfold (Tetracoralla), Sixfold (Hexacoralla), and Eightfold corals
-(Octocoralla). The fourfold corals form the common primary group of the
-class, out of which the sixfold and eightfold have developed as two
-diverging branches.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 4 Classes and 30 Orders of the Animal Plants, or Zoophytes._
-
- ----------------+--------------------+--------------------+---------------
-  _Class of the_ | _Legions of the_   | _Orders of the_    | _A Genus Name_
-  _Zoophytes._   |  _Zoophytes._      | _Zoophytes._       |  _as example._
- ----------------+--------------------+--------------------+---------------
-        I.        { I. Myxospongiae      { 1. Archispongina | Archispongia
-                  { _Mucous Sponges_    { 2. Halisarcina   | Halisarca
-    =Sponges=     {                                        |
-                  { II. Fibrospongiae    { 3. Chalynthina   | Spongilla
-    +Spongiae+     {_Fibrous Sponges_    { 4. Geodina       | Ancorina
-        or        {                     { 5. Hexactinella  | Euplectella
-    +Porifera+    {                                        |
-                  { III. Calcispongiae   { 6. Ascones       | Olynthus
-                  {_Calcareous Sponges_ { 7. Leucones      | Dyssycus
-                  {                     { 8. Sycones       | Sycurus
-                                                           |
-                                                           |
-       II.        { IV. Tetracoralla    { 9. Rugosa        | Cyathophyllum
-                  {_Fourfold Corals_    { 10. Paranemeta   | Cereanthus
-    =Corals=      {                                        |
-                  { V. Hexacoralla      { 11. Cauliculata  | Antipathes
-    +Coralla+     {_Sixfold Corals_     { 12. Madreporaria | Astraea
-        or        {                     { 13. Halirhoda    | Actinia
-    +Anthozoa+    {                                        |
-                  { VI. Octocoralla     { 14. Alcyonida    | Lobularia
-                  {_Eightfold Corals_   { 15. Gorgonida    | Isis
-                  {                     { 16. Pennatulida  | Veretillum
-                                                           |
-                                                           |
-      III.        { VII. Archydrae       } 17. Hydraria     | Hydra
-                  {_Primaeval Polyps_    }                  |
-  =Jelly-polyps=  {                                        |
-                  { VIII. Leptomedusae   { 18. Vesiculata   | Sertularia
-   +Hydromedusae+  {_Soft Jelly-fish_    { 19. Ocellata     | Tubularia
-                  {                     { 20. Siphonophora | Physophora
-        or        {                                        |
-                  { IX. Trachymedusae    { 21. Marsiporchida| Trachynema
-  =Hood-jellies=  { _Hard Jelly-fish_   { 22. Phyllorchida | Geryonia
-                  {                     { 23. Elasmorchida | Charybdae
-     +Medusa+     {                                        |
-                  { X. Calycozoa        } 24. Podactinaria | Lucernaria
-                  { _Stalked Jellies_   }                  |
-                  {                                        |
-                  { XI. Discomedusae     { 25. Semaeostomeae  | Aurelia
-                  { _Disc-jellies_      { 26. Rhizostomeae  | Crambessa
-                                                           |
-                                                           |
-       IV.        { XII. Eurystoma      } 27. Beroida      | Beroe
-                  { _Wide-mouthed_      }                  |
-  =Comb-jellies=  {                                        |
-                  { XIII. Stenostoma    { 28. Saccata      | Cydippe
-   +Ctenophora+   { _Narrow-mouthed_    { 29. Lobata       | Eucharis
-                  {                     { 30. Taeniata      | Cestum
-
-        ----------------------------------------------------------------
-
-                 Ctenophora                      Hydromedusae
-             Taeniata   Lobata                    Rhizostomeae
-                 |        |                           |
-                 |        |                           |
-                 \---v----/                      Semaeostomeae
-                  Saccata                        DISCOMEDUSAE
-                STENOSTOMA                            |
-                     |      Trachymedusae              |   Siphonophora
-                     |            |                   |         |
-                     |            |   Lucernaria      |         |
-                EURYSTOMA>        |   Calycozoa       |         |
-                     |            |       |           |         |
-                     |            |       |           |         |
-                     \-------------------------v----------------/
-                                           LEPTOMEDUSAE
-                              Coralla          |
-                                   Octocoralla |
-                         Hexacoralla    |      |
-                              |         |      |
-                              |         |      |
-                              \----v----/      |
-                               Tetracoralla    |
-                Spongiae                 |      |
-        Fibrospongiae     Calcispongiae   |      |
-         Chalynthina   Leucones  Sycones|      |
-              |           |        |    |      |
-              |           |        |    |      |
-              |           |        |    |      |
-  Hexactinella|Geodina Dyssycus Sycurus |    Hydroida
-       |      |   |       |        |    |      | Cordylophora
-       |      |   |       |        |    |      |     |     Hydra
-       \------v---/       \-----v--/    |      |     |       |
-              |              Ascones    |      |     |       |
-              |  Myxospongia    |       |      \-----v-------/
-              |  Halisarcina    |       |         HYDROIDA
-              |      |          |   Procorallum        |
-              |      |          |       |              |
-         CHALYNTHUS  |       OLYNTHUS   |              |
-              |      |          |       \-----v--------/
-              \------v----------/        Hydroida
-                Archispongiae                 |
-                     |                       |
-                     |                    Archydra
-                     |                       |
-                     \--------------v--------/
-                                Protascus
-                                    |
-                                 Gastraea
-
-The second class of Sea-nettles is formed by the _Hood-jellies_ (Medusae)
-or _Polyp-jellies_ (Hydromedusae). While most corals form stocks like
-plants, and are attached to the bottom of the sea, the Hood-jellies
-generally swim about freely in the form of gelatinous bells. There are,
-however, numbers of them, especially the lower forms, which adhere to
-the bottom of the sea, and resemble pretty little trees. The lowest and
-simplest members of this class are the little fresh-water polyps (Hydra
-and Cordylophora). We may look upon them as but little changed
-descendants of those _Primaeval polyps_ (Archydrae), from which, during
-the primordial period, the whole division of the Sea-nettles originated.
-Scarcely distinguishable from the Hydra are the adherent Hydroid polyps
-(Campanularia, Tubularia), which produce freely swimming medusae by
-budding, and out of the eggs of these there again arise adherent polyps.
-These freely swimming Hood-jellies are mostly of the form of a mushroom,
-or of an umbrella, from the rim of which many long and delicate
-tentacles hang. They are among the most beautiful and most interesting
-inhabitants of the sea. The remarkable history of their lives, and
-especially the complicated alternation of generation of polyps and
-medusae, are among the strongest proofs of the truth of the theory of
-descent. For just as Medusae still daily arise out of the Hydroids, did
-the freely swimming medusa-form originally proceed, phylogenetically,
-out of the adherent polyp-form. Equally important for the theory of
-descent is the remarkable _division of labour_ of the individuals, which
-among some of them is developed to an astonishingly high degree, more
-especially in the splendid _Siphonophora_.(37) (Plate VII. Fig. 13.)
-
-The third class of Sea-nettles--the peculiar division of Comb-jellies
-(Ctenophora), probably developed out of a branch of the Hood-jellies.
-The Ctenophora, which are also called Ribbed-jellies, possess a body of
-the form of a cucumber, which, like the body of most Hood-jellies, is as
-clear and transparent as crystal or cut glass. Comb or Ribbed-jellies
-are characterized by their peculiar organs of motion, namely, by eight
-rows of paddling, ciliated leaflets, which run in the form of eight ribs
-from one end of the longitudinal axis (from the mouth) to the opposite
-end. Those with narrow mouths (Stenostoma) probably developed later out
-of those with wide mouths (Eurystoma). (Compare Plate VII. Fig. 16.)
-
-The third tribe of the animal kingdom, the phylum of _Worms_ or
-worm-like animals (Vermes, or Helminthes), contains a number of
-diverging branches. Some of these numerous branches have developed into
-well-marked and perfectly independent classes of Worms, but others
-changed long since into the original, radical forms of the four higher
-tribes of animals. Each of these four higher tribes (and likewise the
-tribe of Zoophytes) we may picture to ourselves in the form of a lofty
-tree, whose branches represent the different classes, orders, families,
-etc. The phylum of Worms, on the other hand, we have to conceive as a
-low bush or shrub, out of whose root a mass of independent branches
-shoot up in different directions. From this densely branched shrub, most
-of the branches of which are dead, there rise four high stems with many
-branches. These are the four lofty trees just mentioned as representing
-the higher phyla--the Echinoderma, Articulata, Mollusca, and Vertebrata.
-These four stems are directly connected with one another at the root
-only, to wit, by the common primary group of the Worm tribe.
-
-The extraordinary difficulties which the systematic arrangement of Worms
-presents, for this reason merely, are still more increased by the fact
-that we do not possess any fossil remains of them. Most of the Worms had
-and still have such soft bodies that they could not leave any
-characteristic traces in the neptunic strata of the earth. Hence in this
-case again we are entirely confined to the records of creation furnished
-by ontogeny and comparative anatomy. In making then the exceedingly
-difficult attempt to throw a few hypothetical rays of light upon the
-obscurity of the pedigree of Worms, I must therefore expressly remark
-that this sketch, like all similar attempts possesses only a provisional
-value.
-
-The numerous classes distinguished in the tribe of Worms, and which
-almost every zoologist groups and defines according to his own personal
-views, are, in the first place, divided into two essentially different
-groups or branches, which in my Monograph of the Calcareous Sponges I
-have termed Acoelomi and Coelomati. For all the lower Worms which are
-comprised in the class of Flat-worms (Platyhelminthes), (the
-Gliding-worms, Sucker-worms, Tape-worms), differ very strikingly from
-other Worms, in the fact that they possess neither blood nor body-cavity
-(no coelome); they are, therefore, called Acoelomi. The true cavity, or
-coelome, is completely absent in them as in all the Zoophytes; in this
-important respect the two groups are directly allied. But _all other
-Worms_ (like the four higher tribes of animals) possess a genuine
-body-cavity and a vascular system connected with it, which is filled
-with blood; hence we class them together as _Coelomati_.
-
-The main division of _Bloodless Worms_ (Acoelomi) contains, according to
-our phylogenetic views, besides the still living Flat-worms, the unknown
-and extinct primary forms of the whole tribe of Worms, which we shall
-call the Primaeval Worms (Archelminthes). The type of these _Primaeval
-Worms_, the ancient Prothelmis, may be directly derived from the Gastraea
-(p. 133). Even at present the Gastrula-form--the faithful historical
-portrait of the Gastraea--recurs in the ontogenesis of the most different
-kinds of worms as a transient larva-form. The ciliated Gliding-worms
-(Turbellaria), the primary group of the present Planary or Flat-worms
-(Platyhelminthes), are the nearest akin to the Primaeval Worms. The
-parasitical Sucker-worms (Trematoda) arose out of the Gliding-worms,
-which live freely in water, by adaptation to a parasitical mode of life;
-and out of them later on--by an increasing parasitism--arose the
-Tape-worms (Cestoda).
-
-Out of a branch of the Acoelomi arose the second main division of the
-Worm tribe, the Worms with blood and body-cavity (Coelomati): of these
-there are seven different classes.
-
-The Pedigree on p. 151 shows how the obscure phylogeny of the seven
-classes of Coelomati may be supposed to stand. We shall, however,
-mention these classes here quite briefly, as their relationships and
-derivation are, at present, still very complicated and obscure. More
-numerous and more accurate investigations of the ontogeny of the
-different Coelomati will at some future time throw light upon their
-phylogenesis.
-
-The Round Worms (Nemathelminthes) which we mention as the first class of
-the Coelomati, and which are characterized by their cylindrical form,
-consist principally of parasitical Worms which live in the interior of
-other animals. Of human parasites, the celebrated Trichinae, the
-Maw-worms, Whip-worms, etc., for example, belong to them. The Star-worms
-(Gephyrea) which live exclusively in the sea are allied to round worms,
-and the comprehensive class of Ring-worms (Annelida) are allied to the
-former. To the Ring-worms, whose long body is composed of a number of
-segments, all alike in structure, belong the Leeches (Hirudinea),
-Earth-worms (Lumbricina), and all the marine bristle-footed Worms
-(Chaetopoda). Nearly akin to them are the Snout-worms (Rhynchocoela), and
-the small microscopic Wheel-worms (Rotifera). The unknown, extinct,
-primary forms of the tribe of Sea-stars (Echinoderma), and of the tribe
-of the articulated animals (Arthropoda), were nearest akin to the
-Ring-worms. On the other hand, we must probably look for the primary
-forms of the great tribe of Molluscs in extinct Worms, which were very
-closely related to the Moss-polyps (Bryozoa) of the present day; and for
-the primary forms of the Vertebrata in the unknown Coelomati, whose
-nearest kin of the present day are the Sea-sacs, especially the Ascidia.
-
-SYSTEMATIC SURVEY
-
-_Of the 8 Classes and 22 Orders of the Worm Tribe._
-
-(Compare Gen. Morph. ii. Plate V. pp. 75-77.)
-
-
-  ------------------+-------------------------+----------------------+------------------
-  _Classes_         |                         |  _Systematic_        |
-  _of the_          |  _Orders of the_        |  _Name of the_       | _Name of a Genus_
-  _Worm Tribe._     |   _Worm Tribe._         | _Orders of Worms_.   |  _as example._
-                    |                         |                      |
-  ------------------+-------------------------+----------------------+------------------
-  1. _Flat_          {  1. Primaeval worms     |  1. Archelminthes    | Prothelmis
-  _Worms_            {  2. Gliding-worms      |  2. Turbellaria      | Planaria
-  Platyhel-          {  3. Sucker-worms       |  3. Trematoda        | Distoma
-  minthes            {  4. Tape-worms         |  4. Cestoda          | Taenia
-                                              |                      |
-  2. _Round_         {  5. Arrow-worms        |  5. Chaetognatha      | Sagitta
-  _Worms_            {  6. Thread-worms       |  6. Nematoda         | Trichina
-  Nemathel-          {  7. Hook-headed        |  7. Acanthocephala   | Echinorhynchus
-  minthes            {      worms             |                      |
-                                              |                      |
-  3. _Moss_          }  8. Horse-shoe-lipped  |  8. Lophopoda        | Alcyonella
-  _Polyps_           }  9. Circle-lipped      |  9. Stelmopoda       | Retepora
-  Bryozoa            }                        |                      |
-                                              |                      |
-  4. _Sea-sacs_      { 10. Sea-squirts        | 10. Ascidia          | Phallusia
-  Tunicata           { 11. Sea-barrels        | 11. Thaliacea        | Salpa
-                                              |                      |
-  5. _Proboscideans_ } 12. Tongue-worms       | 12. Enteropneusta    | Balanoglossus
-  Rhynchocoela       } 13. Cord-worms         | 13. Nemertina        | Borlasia
-                                              |                      |
-                     { 14. Star-worms without | 14. Sipunculida      | Sipunculus
-  6. _Star-Worms_    {       bristles         |                      |
-  Gephyrea           { 15. Star-worms with    | 15. Echiurida        | Echiurus
-                     {       bristles         |                      |
-                                              |                      |
-  7. _Wheel_         }                        |                      |
-  _Animalcule_       } 16. Wheel-worms        | 16. Rotatoria        | Hydatina
-  Rotifera           }                        |                      |
-                                              |                      |
-                     { 17. Bear-worms         | 17. Arctisca         | Macrobiotus
-                     { 18. Worms with claws   | 18. Onychophora      | Peripatus
-  8. _Ring_          { 19. Leeches            | 19. Hirudinea        | Hirudo
-  _Worms_            { 20. Land-worms         | 20. Drilomorpha      | Lumbricus
-  Annelida           { 21. Mailed worms       | 21. Phracthelminthes | Crossopodia
-                     { 22. Bristle-footed     | 22. Chaetopoda        | Aphrodite
-                     {      worms             |                      |
-
-        ----------------------------------------------------------------
-
-                       Chaetopoda
-                           |          Drilomorpha
-                           |               |
-                           \-------v-------/
-                                   |
-                  Phracthelminthes |
-                          |        |
-                 Echiurida|        |   Hirudinea
-        Sipunculida  |    |        |       |
-            |        |    |        |       |   Onychophora
-            \----v---/    |        |       |        |
-               +Gephyrea+ |        |       |        |  Arctisca
-                     |    |        |       |        |     |
-                     |    |        |       |        \--v---/
-      Chaetognatha    |    \--v-----/       |           |
-           |         |       |             \-----v-----/
-  Nematoda |         |       |                   |
-     |     |         |       \---------v---------/
-     \--v--/         |              +Annelida+
-        |  Acantho-  |                   |
-        |   cephala  | Stelmopoda        |
-        |     |      |     |             |              Enteropneusta
-        \--v--/      |     |             |                   |
-   +Nemathelminthes+ | Lophopoda         |         Ascidia   |
-           |         |  +Bryozoa+        |  Thalicea |       |  Nemertina
-           |         |     |             |    |      |       |     |
-           |         |     | +Rotifera+  |    |      |       |     |
-           |         |     |    |        |    |      |       \---v-/
-           |         |     |    |        |    |      |    +Rhynchocoela+
-           |         |     |    |        |    \--v---/           |
-           |         |     |    \----v---/    +Tunicata+         |
-           |         |     |         |           |               |
-           \-----------------------v-----------------------------/
-                  +Coelomati+ (_worms with body-cavity_)
-                                   |
-             Cestoda               |
-                 |                 |
-                 |                 |
-             Trematoda             |
-                 |                 |
-                 |                 |
-           Turbellaria             |
-         +Platyhelminthes+         |
-                 |                 |
-                 |                 |
-                 \-------v---------/
-             +Acoelomi+ (_worms without body-cavity_)
-                         |
-                         |
-                   Archelminthes
-                    +Prothelmis+
-                         |
-                         |
-                      +Gastraea+
-
-
-The class of Sea-sacs (Tunicata) is one of the most remarkable among
-Worms. They all live in the ocean, where some of the Ascidiae adhere to
-the bottom, while others (the sea-barrels, or Thaliacea) swim about
-freely. In all of them the non-jointed body has the form of a simple
-barrel-shaped sack, which is surrounded by a thick cartilaginous mantle.
-This mantle consists of the same non-nitrogenous combination of carbon,
-which, under the name of cellulose, plays an important part in the
-Vegetable Kingdom, and forms the largest portion of vegetable cellular
-membranes, and consequently also the greater part of wood. The
-barrel-shaped body generally possesses no external appendages. No one
-would recognise in them a trace of relationship to the highly
-differentiated vertebrate animals. And yet this can no longer be
-doubted, since Kowalewsky's investigations, which in the year 1867
-suddenly threw an exceedingly surprising and unmistakable light upon
-them. From these investigations it has become clear that the individual
-development of the adherent simple Ascidian Phallusia agrees in most
-points with that of the lowest vertebrate animal, namely, the Lancelet
-(Amphioxus lanceolatus). The early stages of the Ascidia possess the
-beginnings of the _spinal marrow_ and the _spinal column_ (chorda
-dorsalis) lying beneath it, which are the two most essential and most
-characteristic organs of the vertebrate animal. Accordingly, of all
-invertebrate animals known to us, the _Tunicates are without doubt the
-nearest blood relations of the Vertebrates_, and must be considered as
-the nearest relations of those Worms out of which the vertebrate tribe
-has developed. (Compare Plates XII. and XIII.)
-
-While thus different branches of the Coelomatous group of the Worms
-furnish us with several genealogical links leading to the four higher
-tribes of animals, and give us important phylogenetic indications of
-their origin, the lower group of Acoelomi, on the other hand, show close
-relationships to the Zoophytes, and to the Primaeval animals. The great
-phylogenetic interest of the Worm tribe rests upon this peculiar
-intermediate position.
-
-
-
-
-CHAPTER XIX.
-
-PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-II. MOLLUSCA, STAR-FISHES, AND ARTICULATED ANIMALS.
-
-
-  Tribe of Molluscs.--Four Classes of Molluscs: Lamp-shells
-  (Spirobranchia); Mussels (Lamellibranchia); Snails (Cochlides);
-  Cuttle-fish (Cephalopoda).--Tribe of Star-fishes, or
-  Echinoderma.--Their Derivation from Ringed Worms (Mailed Worms,
-  or Phracthelminthes).--The Alternation of Generation in the
-  Echinoderma.--Four Classes of Star-fish: Sea-stars (Asteridea);
-  Sea-lilies (Crinoidea); Sea-urchins (Echinidea); Sea-cucumbers
-  (Holothuridea).--Tribe of Articulated Animals, or
-  Arthropoda.--Four Classes of Articulated Animals: Branchiata, or
-  Crustacea, breathing through gills; Jointed Crabs; Mailed
-  Crabs; Articulata Tracheata, breathing through Air
-  Tubes.--Spiders (Long Spiders, Round
-  Spiders).--Myriopods.--Insects.--Chewing and Sucking
-  Insects.--Pedigree and History of the Eight Orders of Insects.
-
-
-The great natural main groups of the animal kingdom, which we have
-distinguished as TRIBES, or PHYLA ("types" according to Baer and Cuvier),
-are not all of equal systematic importance for our phylogeny or history
-of the pedigree of the living world. They can neither be classed in a
-single series of stages, one above another, nor be considered as
-entirely independent stems, nor as equal branches of a single
-family-tree. It seems rather (as we saw in the last chapter) that the
-tribe of Protozoa, the so-called primaeval animals, is the common radical
-group of the whole animal kingdom. Out of the Gastraeada--which we class
-among the Protozoa--the Zoophytes and the Worms have developed, as two
-diverging branches. We must now in turn look upon the varied and
-much-branching tribe of Worms as the common primary group, out of which
-(from perfectly distinct branches) arose the remaining tribes, the four
-higher phyla of the animal kingdom. (Compare the Pedigree, p. 133.)
-
-Let us now take a genealogical look at these four higher tribes of
-animals, and try whether we cannot make out the most important outlines
-of their pedigree. Even should this attempt prove defective and
-imperfect, we shall at all events have made a beginning, and paved the
-road for subsequent and more satisfactory attempts.
-
-It does not matter in what succession we take up the examination of the
-four higher tribes. For these four phyla have no close relationship
-whatever among one another, but have grown out from entirely distinct
-branches of the group of Worms (p. 133). We may consider the tribe of
-Molluscs as the most imperfect and the lowest in point of morphological
-development. We nowhere meet among them with the characteristic
-articulation or segmented formation of the body, which distinguishes
-even the Ring-worms, and which in the other three higher tribes--the
-Echinoderma, Articulata, and Vertebrata--is most essentially connected
-with the high development of their forms, their differentiation, and
-perfection. The body in all Molluscs--in mussels, snails, etc.--is a
-simple non-jointed sack, in the cavity of which lie the intestines. The
-nervous system consists not of a cord but of several distinct (generally
-three) pairs of knots loosely connected with one another. For these and
-many other anatomical reasons, I consider the tribe of Molluscs (in
-spite of the high physiological development of its most perfect forms)
-to be morphologically the lowest among the four higher tribes of
-animals.
-
-Whilst, for reasons already given, we exclude the Moss-polyps, and
-Tunicates--which have hitherto been generally classed with the tribe of
-Molluscs--we retain as genuine Molluscs the following four classes:
-Lamp-shells, Mussels, Snails, and Cuttles. The two lower classes of
-Molluscs, the Lamp-shells and Mussels, possess neither head nor teeth,
-and they can therefore be comprised under one main class, or branch, as
-headless animals (Acephala), or toothless animals (Anodontoda). This
-branch is also frequently called that of the clam-shells (Conchifera, or
-Bivalvia), because all its members possess a two-valved calcareous
-shell. In contrast to these the two higher classes of Molluscs, the
-snails and cuttles, may be represented as a second branch with the name
-of Head-bearers (Cephalophora), or Tooth-bearers (Odontophora), because
-both head and teeth are developed in them.
-
-The soft, sack-shaped body in most Molluscs is protected by a calcareous
-shell or house, which in the Acephala (lamp-shells and mussels) consists
-of two valves, but in the Cephalophora (snails and cuttles) is generally
-a spiral tube (the so-called snail's house). Although these hard
-skeletons are found in large quantities in a petrified state in all the
-neptunic strata, yet they tell us but little of the historical
-development of the tribe, which must have taken place for the most part
-in the primordial period. Even in the Silurian strata we find fossil
-remains of all the four classes of Molluscs, one beside the other, and
-this, conjointly with much other evidence, distinctly proves that the
-tribe of Molluscs had then obtained a strong development, when the
-higher tribes, especially the Articulates and Vertebrates, had scarcely
-got beyond the beginning of their historical development. In subsequent
-periods, especially in the primary and secondary periods, these higher
-tribes increased in importance more and more at the expense of Molluscs
-and Worms, which were no match for them in the struggle for life, and
-accordingly decreased in number. The still living Molluscs and Worms
-must be considered as only a proportionately small remnant of the vast
-molluscan fauna, which greatly predominated in the primordial and
-primary periods over the other tribes. (Compare Plate VI. and
-explanation in the Appendix.)
-
-No tribe of animals shows more distinctly than do the Molluscs, how very
-different the value of fossils is in geology and in phylogeny. In
-geology the different species of the fossil shells of Molluscs are of
-the greatest importance because they serve as excellent marks whereby to
-characterize the different groups of strata, and to fix their relative
-ages. As far as relates to the genealogy of Molluscs, however, they are
-of very little value, because, on the one hand, the shells are parts of
-quite subordinate morphological importance, and because the actual
-development of the tribe belongs to the earlier primordial period, from
-which no distinct fossils have been preserved. If therefore we wish to
-construct the pedigree of Molluscs, we are mainly dependent upon the
-records of ontogeny and comparative anatomy from which we obtain
-something like the following result. (Gen. Morph. ii. Plate VI. pp.
-102-116.)
-
-The lowest stage of the four classes of genuine Molluscs known to us, is
-occupied by the Lamp-shells or Spiral-gills (Spirobranchia), frequently
-but inappropriately called Arm-footers (Brachiopoda), which have become
-attached to the bottom of the sea. There now exist but few forms of
-this class; for instance, some species of Lingula, Terebratula, and
-others akin to them, which are but feeble remnants of the great variety
-of forms which represented the Lamp-shells in earlier periods of the
-earth's history. In the Silurian period they constituted the principal
-portion of the whole Mollusc tribe. From the agreement which, in many
-respects, their early stage of development presents with the Moss
-animals, it has been concluded that they have developed out of Worms,
-which were nearly related to this class. Of the two sub-classes of
-Lamp-shells, the Hinge-less (Ecardines) must be looked upon as the lower
-and more imperfect, the Hinged (Testicardines) as the higher and more
-fully developed group.
-
-The anatomical difference between the Lamp-shells and the three other
-classes of Molluscs is so considerable that the latter may be
-distinguished from the former by the name of Otocardia. All the
-Otocardia have a heart with chamber (ventricle) and ante-chamber
-(auricle), whereas Lamp-shells do not possess the ante-chamber.
-Moreover, the central nervous system is developed only in the former
-(and not in the latter) in the shape of a complete pharyngeal ring.
-Hence the four classes of Molluscs may be grouped in the following
-manner:--
-
-
-                     {     1. Lamp-shells     }     I. Haplocardia
-  I.  Molluscs       {     (Spirobranchia).   }     (with simple heart).
-  without head.      {
-  _Acephala._        {     2. Mussels         }
-                     {     (Lamellibranchia). }     II. Otocardia
-                                              }     (with chamber
-  II.  Molluscs      {     3. Snails          }     and ante-chamber
-  with head.         {     (Cochlides).       }     to the heart).
-  _Cephalophora._    {     4. Cuttles         }
-                     {     (Cephalopoda).     }
-
-
-The result of these structural dispositions for the history of the
-pedigree of Molluscs, which is confirmed by palaeontology, is that
-Lamp-shells stand much nearer to the primaeval root of the whole tribe of
-Molluscs than do the Otocardia. Probably Mussels and Snails developed as
-two diverging branches out of Molluscs, which were nearly akin to the
-Lamp-shells.
-
-Mussels, or Plate-gills (Lamellibranchia), possess a bivalved shell like
-the Lamp-shells. In the latter, one of the two valves covers the back,
-the other the belly of the animal; whereas in Mussels the two valves lie
-symmetrically on the right and left side of the body. Most Mussels live
-in the sea, only a few in fresh water. The class is divided into two
-sub-classes, Asiphonia and Siphonida, of which the latter were developed
-at a later period out of the former. Among the Asiphonia are Oysters,
-mother-of-pearl Shells, and fresh water Mussels; among the Siphonida,
-which are characterized by a respiratory tube, are the Venus-shells,
-Razor-shells, and Burrowing Clams. The higher Molluscs seem to have
-developed at a later period out of those without head and teeth; they
-are distinguished from the latter by the distinct formation of the head,
-and more especially by a peculiar kind of tooth apparatus. Their tongue
-presents a curious plate, armed with a great number of teeth. In our
-common Vineyard Snail (Helix pomatia) the number of teeth amount to
-21,000, and in the large Garden Slug (Limax maximus) to 26,800.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 4 Classes, 8 Sub-classes, and 21 Orders of Molluscs._
-
-
-  ------------------+-----------------------+------------------------+-------------------
-    _Classes of_    |    _Sub-classes of_   |    _Orders of_         |  _Systematic Name_
-    _Molluscs._     |      _Molluscs._      |    _Molluscs._         |   _of the Orders._
-  ------------------+-----------------------+------------------------+-------------------
-          I. _Molluscs without head or teeth_: ACEPHALA _or_ ANODONTODA.
-  ---------------------------------------------------------------------------------------
-      I.            {   I. Ecardines        { 1. Stalked              1. Lingulida
-  =Lamp-shells=     {      _Hinge-less_     { 2. Flattened            2. Craniada
-                    {
-  +Spirobranchia+   {
-       or           {
-  +Brachiopoda+     {  II. Testicardines    { 3. Fleshy armed         3. Sarcobrachia
-                    {     _Hinge-less_      { 4. Calcareous-armed     4. Sclerobrachia
-
-
-      II.           { III. Asiphonia        { 5. One-muscled          5. Monomya
-    =Mussels=       { _Mussels without_     { 6. Uneven-muscled       6. Heteromya
-      or            { _respiratory tubes_   { 7. Even-muscled         7. Isomya
-  =Plate-gills=     {
-                    {
-  +Lamellibranchia+ {  IV. Siphonida        { 8. Round-mantled        8. Integripallia
-        or          {  _Mussels with_       { 9. Ray-mantled          9. Sinupalliata
-  +Phyllobranchia+  { _respiratory tubes_   { 10. Tube-mussels       10. Inclusa
-
-  ---------------------------------------------------------------------------------------
-          II. _Molluscs with head and teeth_: CEPHALOPHORA _or_ ODONTOPHORA.
-  ---------------------------------------------------------------------------------------
-
-                    {   V. Stump-headed     { 11. Tube-snails        11. Scaphopoda
-      III.          {      _Perocephala_    { 12. Butterfly-snails   12. Pteropoda
-     =Snails=       {
-                    {                       { 13. With hind gills    13. Opisthobranchia
-   +Cochlides+      {                       { 14. With fore gills    14. Prosobranchia
-       or           {   VI. Large-headed    { 15. Swimming-snails    15. Heteropoda
-  +Gasteropoda+     {      _Delocephala_    { 16. Beetle-snails      16. Chitonoida
-                    {                       { 17. Snails with lungs  17. Pulmonata
-
-
-                       VII. Chamber-Poulps  { 18. Pearl boats        18. Nautilida
-      IV.                  with four gills  { 19. Ammon's horns      19. Ammonitida
-    =Cuttles=       }     _Tetrabranchia_   {
-      or            }
-    =Poulps=        } VIII. Ink-Poulps with { 20. Ten-armed          20. Decabrachiones
-                    }       two gills       {
-  +Cephalopoda+     }       _Dibranchia_    { 21. Eight-armed        21. Octobrachiones
-
-        ----------------------------------------------------------------
-
-                                                      Dibranchia
-                         Heteropoda                        |
-                             |       _Prosobranchia_       |
-  _Pulmonata_                |              |         Tetrabranchia
-      |      Lipobranchia    |              |         Cephalopoda
-      |            |         |              |    (=Cuttles= or =Poulps=)
-      |     Gymnobranchia    |              |               |
-      |            |         \-------v------/               |
-      |            |                 |                      |
-      |     Pleurobranchia           |       Chitonides     |
-      |    _Opisthobranchia_         |            |         |
-      |            |                 |            |         |
-      \---------------------------------v---------/         |
-                                        |                   |
-                                   _Delocephala_            |
-                                        |                   |
-                                        |                   |
-                                        \--------v----------/
-                                                  |
-                                                  |       _Pteropoda_
-                        Inclusa                   |            |
-                           |                      |            |
-                           |                      \------v-----/
-                       Sinupalliata                      |
-                           |                  Scaphopoda |
-                           |                      |      |
-                     Integripalliata              \---v--/
-  Sclerobrachia       _Siphoniata_                    |
-        |                   |                   _Perocephala_
-        |                   |                     Cochlides
-        |                   |                     (=Snails=)
-   Sarcobrachia        _Asiphonia_                    |
-  _Testicardines_     Lamellibranchia                 |
-        |                (=Mussels=)                  |
-        |                    |                        |
-   _Ecardines_               \----------v-------------/
-  Spirobranchia                         |
-   (=Lamp-shells=)                     Otocardia
-        |            (Molluscs with chamber and ante-chamber
-        |                          to the heart)
-        |                                |
-        |                                |
-        \-----------------v--------------/
-                          |
-              Promollusca (Primaeval Molluscs)
-                Molluscs with simple heart
-                          |
-                       (Worms)
-                          |
-                       Gastraea
-
-
-We distinguish two sub-classes among the Snails (Cochlides, or
-Gasteropoda), namely, the Stump-headed and the Large-headed Snails. The
-Stump-headed Snails (Perocephala) are very closely allied to Mussels
-(through the Tooth-shells), and also to the Cuttle-fish (through the
-Butterfly-snails). The more highly developed Snails, with large heads
-(Delocephala), can be divided into Snails with gills (Branchiata) and
-Snails with lungs (Pulmonata). Among the latter are the Land-snails, the
-only Molluscs which have left the water and become habituated to a life
-on land. The great majority of Snails live in the sea, only a few live
-in fresh water. Some River-snails in the tropics (the Ampullaria) are
-amphibious, living sometimes on land, sometimes in water, and at one
-time they breathe through gills, at another through lungs. They have
-both kinds of respiratory organs, like the Mud-fish and Gilled Newts
-among the Vertebrata.
-
-The fourth and last class, and at the same time the most highly
-developed class of Molluscs, is that of the Cuttles, or Poulps, also
-called Cephalopoda (foot attached to the head). They all live in the
-sea, and are distinguished from Snails by eight, ten, or more long arms,
-which surround the mouth in a circle. The Cuttles existing in our recent
-oceans--the Sepia, Calamary, Argonaut, and Pearly Nautilus--are, like
-the few Spiral-gill Lamp-shells of the present time, but a poor remnant
-of the host which represents this class in the oceans of the primordial,
-primary, and secondary periods. The numerous fossil "Ammon's horns"
-(Ammonites), "pearl boats" (Nautilus), and "thunderbolts" (Belemnites)
-are evidences of the long since extinct splendour of the tribe. The
-Poulps, or Cuttles, have probably developed out of a low branch of the
-snail class, out of the Butterfly-snails (Pteropoda) or kindred forms.
-
-The different sub-classes and orders, distinguished in the four classes
-of Molluscs, whose systematic succession is given on the Table (p.
-160), furnish various proofs of the validity of the law of progress by
-their historical development and by the systematic development
-corresponding to it. As however these subordinate groups of Molluscs are
-in themselves of no further special interest, I must refer to the sketch
-of their pedigree on p. 161, and to the detailed pedigree of Molluscs
-which I have given in my General Morphology, and I shall now at once
-turn to the consideration of the tribe of Star-fishes.
-
-The Star-fishes (Echinoderma, or Estrellae) among which are the four
-classes of Sea-stars, Sea-lilies, Sea-urchins, and Sea-cucumbers are one
-of the most interesting divisions of the animal kingdom, and yet we know
-less about them than about any. They all live in the sea. Every one who
-has been at the sea shore must have seen at least two of their forms,
-the Sea-stars and the Sea-urchins. The tribe of Star-fishes must be
-considered as a completely independent tribe of the animal kingdom on
-account of its very peculiar organization, and must be carefully
-distinguished from the Animal-plants--Zoophytes, or Coelenterata, with
-which it is still frequently but erroneously classed under the name
-Radiata (as for example, by Agassiz, who even to this day defends this
-error of Cuvier's, together with many others).
-
-All Echinoderma are characterized, and at the same time distinguished
-from all other animals, by a very remarkable apparatus for locomotion,
-which consists of a complicated system of canals or tubes, filled with
-sea water from without. The sea water in these aqueducts is moved partly
-by the strokes of the cilia, or vibratile hairs lining their walls, and
-partly by the contractions of the muscular walls of the tubes
-themselves, which resemble india-rubber bags. The water is pressed from
-the tubes into a number of little hollow feet, which thereby become
-widely distended, and are then employed for walking and suction. The
-Sea-stars are moreover characterized by a peculiar calcareous formation
-in the skin, which in most cases forms a firm, well-closed coat of mail,
-composed of a number of plates. In almost all Echinoderma the body
-consists of five radii (counterparts, or antimera) standing round the
-main axis of the body, where they meet. It is only in some species of
-Sea-stars that the number of these radii amount to more than five--to
-6-9, 10-12, or even to 20-40; and in this case the number of radii is
-generally not constant, but varies in different individuals of one
-species.
-
-The historical development and the pedigree of the Echinoderma are
-completely revealed to us by their numerous and, in most cases,
-excellently preserved fossil remains, by their very remarkable
-individual developmental history, and by their interesting comparative
-anatomy; this is the case with no other tribe of animals, even the
-Vertebrata themselves are not to be excepted. By a critical use of those
-three archives, and by a careful comparison of the results derived from
-their study, we obtain the following genealogy of the Star-fishes, which
-I have already published in my General Morphology (vol. ii. Plate IV.
-pp. 62-77.)
-
-The most ancient and original group of the Star-fishes, the primary form
-of the whole phylum, consists of the class of the true Sea-stars
-(Asterida). This is established by numerous and important arguments in
-anatomy and the history of development, but above all by the irregular
-and varying number of the radii, or antimera, which in all other
-Echinoderma is limited, without exception, to five. Every Star-fish
-consists of a central, small, body-disc, all round the circumference of
-which are attached five or several long articulated arms. _Each arm of
-the Star-fish essentially corresponds in its organisation with an
-articulated worm_ of the class of Ring-worms, or Annelida (p. 149). I
-therefore consider the Star-fish as a genuine _stock or cormus of five
-or more articulated worms_, which have arisen by the star-wise growth of
-a number of buds out of a central mother-worm. The connected members,
-thus grouped like the rays of a star, have inherited from the
-mother-worm the common opening of the mouth, and the common digestive
-cavity (stomach) lying in the central body-disc. The end by which they
-have grown together, and which fuses in the common central disc,
-probably corresponds to the posterior end of the original independent
-worms.
-
-In exactly the same way several individuals of certain kinds of worms
-are united so as to form a star-like cormus. This is the case in the
-_Botryllidae_, compound Ascidians, belonging to the class of the
-Tunicata. Here also the posterior ends of the individual worms have
-grown together, and have formed a common outlet for discharges, a
-central cloaca; whereas at the anterior end each worm still possesses
-its own mouth. In Star-fishes the original mouths have probably become
-closed in the course of the historical development of the cormus, or
-colony, whereas the cloaca has developed into a common mouth for the
-whole cormus.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 4 Classes, 9 Sub-classes, and 20 Orders of Star-fishes._
-
-(Compare Gen. Morph. II. Plate IV. pp. 62-67.)
-
-
-  ----------------+-------------------------+---------------------------+------------------
-  _Classes of the | _Sub-classes of the     |    _Orders of the         | _Systematic Name
-  Star-fishes._   | Star-fishes._           |      Star-fishes._        |  of the Orders._
-  ----------------+-------------------------+---------------------------+------------------
-                                                                        |
-                   { I.                      { 1. Primary Stars         | 1. Tecastra
-                   { Sea Stars with radiated { 2. Articulated Stars     | 2. Colastra
-  I.               { stomach                 { 3. Brisinga Stars        | 3. Brisingastra
-  =Sea Stars=      { _Actinogastra_                                     |
-  +Asterida+       {
-                   { II.                     { 4. Serpent Stars         | 4. Ophiastra
-                   { Sea Stars with disc-    { 5. Tree Stars            | 5. Phytastra
-                   { shaped stomach          { 6. Lily Stars            | 6. Crinastra
-                   { _Discogastra_           {                          |
-                                                                        |
-                   { III.                    { 7. Plated Lilies with    | 7. Phatnocrinida
-                   { Lilies with arms        {      arms                |
-                   { _Brachiata_             { 8. Articulated Lilies    | 8. Colocrinida
-                   {                         {      with arms           |
-                                                                        |
-  II.              { IV.                     { 9. Regularly budding     | 9. Pentremitida
-  =Sea Lilies=     { Lilies with buds        {      Lilies              |
-  +Crinoida+       { _Blastoidea_            { 10. Lilies budding on    | 10. Eleutherocrina
-                   {                         {      two sides           |
-                                                                        |
-                   { V.                      { 11. Bladder Lilies       | 11. Agelacrinida
-                   { Bladder Lilies          {       without stalks     |
-                   { _Cystidea_              { 12. Bladder Lilies       | 12. Sphaeronitida
-                                             {       with stalks        |
-                                                                        |
-                   { VI.                     { 13. Palechinida with     | 13. Melonitida
-                   { Older Sea Urchins       {       more than 10       |
-                   { (with more than         {       rows of ambulacral |
-                   { 20 rows of plates)      {        plates            |
-  III.             { _Palechinida_           { 14. Palechinida with     | 14. Eocidaria
-  =Sea Urchins=    {                         {       10 rows of         |
-  +Echinida+       { VII.                    {       ambulacral plates  |
-                   { More recent Sea         { 15. Autechinida with     | 15. Desmosticha
-                   { Urchins (with 20        {      band-like ambulacra |
-                   { rows of plates)         { 16. Autechnidia with     | 16. Petalosticha
-                   { _Autechinida_           {      leaf-like ambulacra |
-                                                                        |
-                   { VIII.                   { 17. Eupodia with scuti-  | 17. Aspidochirota
-                   { Sea Cucumbers           {       form tentacles     |
-                   { with aquatic feet       { 18. Eupodia with         | 18. Dendrochirota
-  IV.              { _Eupodia_               {      branching tentacles |
-  =Sea Cucumbers=  {                         {                          |
-                   { IX.                     {                          |
-  +Holothuriae+     { Sea Cucumbers           { 19. Apodia with water-   | 19. Liodermatida
-                   { without aquatic         {       lungs              |
-                   { feet                    { 20. Apodia without       | 20. Synaptida
-                   { _Apodia_                {       water-lungs        |
-
-             ----------------------------------------------------------------
-
-                                                                    Clypeastridae
-                                                                         |
-                                                      Spatangidae         |
-                                                           |             |
-                                              Dysasteridae  |             |
-                                                   |       |             |
-                             Aspidochirota         |       |             |
-                                   |               |       \------v------/
-         Synaptida                 |               |              |
-             |                     |               |         Cassidulidae
-             |                     |               |        +Petalosticha+
-             |                     |               |              |
-             |                     |               |              |
-        Liodermatida               |               |              |
-          +Apodia+                 |               \------v-------/     Echinonidae
-             |                     |                      |                 |
-             |                     |                 Galeritidae             |
-             |                     |                      |   Echinometridae |
-             \---------v-----------/                      |         |       |
-                       |                                  \------v---------/
-                 Dendrochirota                                   |
-                   +Eupodia+                                Latistellae
-                  +Holothuriae+            Salenidae               |
-                \------v------/              |                   |
-                       |                     |                   |
-                       |                     \------v------------/
-                       |                            |
-                       |                      Angustistellae
-                       |                      +Desmosticha+
-                       |                      +Autechinida+
-                       |                            |
-                       |                            |           Colocrinae
-                       |                            |               |
-                       |                            | Sphaeronitidae  |
-    Phytastra          |                            |       |       |
-        |              |                            |       |       |
-        |              |                       Eocidaridae   |       |    Eleutherocrina
-        |              |                            |       |       |           |
-        |              |                            |       |       |           |
-    Ophiastra          |                            |   Agelacrinae  |           |
-  +Discogastra+        |                            |   +Cystidea+  |           |
-        |              |                            |       |       |           |
-        |              |                            |       |       |           |
-        |              |                        Melonitida  |   Phatnocrinae     |
-   Brisingastra        |                        Palechinida |   +Brahiata+   Pentremitida
-        |              |                        +Echinida+  |       |        +Blastoidea+
-        |              |                            |       |       |           |
-        |              |                            |       |       |           |
-     Colastra          \----------v-----------------/       \-------v-----------/
-        |                         |                             +Brachiata+
-        |                         |                              Crinoida
-        |                         |                              Crinastra
-        |                         |                                  |
-        \-------------------------v----------------------------------/
-                                  |
-                               Tocastra
-                            +Actinogastra+
-                              +Asterida+
-                                  |
-                             Phracthelminthes
-                                  |
-                               Coelomati
-                                  |
-                                Gastraea
-
-
-Hence the Star-fishes would be compound stocks of worms which, by the
-radial formation of buds, have developed out of true articulated worms,
-or Annelids. This hypothesis is most strongly supported by the
-comparative anatomy, and by the ontogeny of some Star-fishes (Colastra),
-and of segmented worms. The many-jointed Ring-worms (Annelida) in their
-inner structure are closely allied to the individual arms or radii of
-the Star-fishes, that is to the original single worms, which each arm
-represents. Each of the five worms of the Star-fish is a chain composed
-of a great number of equi-formal members, or metamera, lying one behind
-the other, like every segmented Worm, and every Arthropod. As in the
-latter a central nervous cord, the ventral nerve cord runs along the
-central line of the ventral wall of each segment. On each metameron
-there is a pair of non-jointed feet, and besides these, in most cases,
-one or more hard thorns or bristles similar to those of many Ring-worms.
-A detached arm of a Star-fish can lead an independent life, and can
-then, by the radially-directed growth of buds at one end, again become a
-complete star.
-
-The most important proofs, however, of the truth of my hypothesis are
-furnished by the ontogeny or the individual development of the
-Echinoderma. The most remarkable facts of this ontogeny were first
-discovered in the year 1848 by the great zoologist, Johannes Mueller of
-Berlin. Some of its most important stages are represented on Plates
-VIII. and IX. (Compare their explanation in the Appendix.) Fig. _A_ on
-Plate IX. shows us a common Sea-star (Uraster), Fig. _B_, a Sea-lily
-(Comatula), Fig. _C_, a Sea-urchin (Echinus), and Fig. _D_, a
-Sea-cucumber (Synapta). In spite of the extraordinary difference of form
-manifested by these four representatives of the different classes of
-Star-fishes, yet the beginning of their development is identical in all
-cases. Out of the egg an animal-form develops which is utterly
-different from the fully developed Star-fish, but very like the ciliated
-larvae of certain segmented Worms (Star-worms and Ring-worms). This
-peculiar animal-form is generally called the "larva," but more correctly
-the "nurse" of these Star-fish. It is very small and transparent, swims
-about by means of a fringe of cilia, and is always composed of two equal
-symmetrical halves or sides. The fully grown Echinoderm, however--which
-is frequently more than a hundred times larger, and quite opaque--creeps
-at the bottom of the sea, and is always composed of at least five
-co-ordinate pieces, or antimera, in the form of radii. Plate VIII. shows
-the development of the "nurses" of the four Echinoderms represented on
-Plate IX.
-
-The fully developed Echinoderm arises by a very remarkable process of
-budding in the interior of the "nurse," of which it retains little more
-than the stomach. The nurse, erroneously called the "larva," of the
-Echinoderm, must accordingly be regarded as a solitary worm, which by
-internal budding produces a second generation, in the form of a stock of
-star-shaped and connected worms. The whole of this process is a genuine
-alternation of generations, or metagenesis, not a "metamorphosis," as is
-generally though erroneously stated. A similar alternation of
-generations also occurs in many other worms, especially in some star
-worms (Sipunculidae), and cord worms (Nemertinae). Now if, bearing in mind
-the fundamental law of biogeny, we refer the ontogeny of Echinoderma to
-their phylogeny, then the whole historical development of the
-Star-fishes suddenly becomes clear and intelligible to us, whereas
-without this hypothesis it remains an insoluble mystery. (Compare Gen.
-Morph. ii. pp. 95-99.)
-
-Besides the reasons mentioned, there are many other facts (principally
-from the comparative anatomy of Echinoderma) which most distinctly prove
-the correctness of my hypothesis. I established this hypothesis in 1866,
-without having any idea that _fossil articulated worms_ still existed,
-apparently answering to the hypothetical primary forms. Such have in the
-mean time, however, really been discovered. In a treatise "On the
-Equivalent of the North American Taconic Schist in Germany,"[3] Geinitz
-and Liebe, in 1867, have described a number of articulated Silurian
-worms, which completely confirm my suppositions. Numbers of these very
-remarkable worms are found in an excellent state of preservation in the
-slates of Wuerzbach, in the upper districts of Reusz. They are of the
-same structure as the articulated arm of a Star-fish, and evidently
-possessed a hard coat of mail, a much denser, more solid cutaneous
-skeleton than other worms in general. The number of body-segments, or
-metamera, is very considerable, so that the worms, although no more than
-a quarter or half an inch in breadth, attained a length of from two to
-three feet. The excellently preserved impressions, especially those of
-the Phyllodocites thuringiacus and Crossopodia Henrici, are so like the
-arms of many Star-fish (Colastra) that their true blood relationship
-seems very probable. This primaeval group of worms, which are most
-probably the ancestors of Star-fish, I call Mailed worms
-(Phracthelminthes, p. 150.)
-
-[Illustration: Pl. viii.
-
-STAR FISHES. FIRST GENERATION. WORM PERSON.]
-
-[Illustration: Pl. ix.
-
-STAR FISHES. SECOND GENERATION. WORM STOCK.]
-
-The three other classes of Echinoderma evidently arose at a later period
-out of the class of Sea-stars which have most faithfully retained the
-original form of the stellate colony of worms. The Sea-lilies, or
-Crinoida, differ least from them, but having given up the free, slow
-motion possessed by other Sea-stars, they have become adherent to rocks,
-etc., and form for themselves a long stalk. Some Encrinites, however
-(for example, the Comatulae, Fig. _B_, on Plates VIII. and IX.),
-afterwards detach themselves from their stalk. The original worm
-individuals in the Crinoida are indeed no longer preserved in the same
-independent condition as in the case of the common star-fish; but they
-nevertheless always possess articulated arms extending from a common
-central disc. Hence we may unite the Sea-lilies and Sea-stars into a
-main-class, or branch, characterized as possessing articulated arms
-(Colobrachia).
-
-In the other two classes of Echinoderma, the Sea-urchins and
-Sea-cucumbers, the articulated arms are no longer present as independent
-parts, but, by the increased centralization of the stock, have
-completely fused so as to form a common, inflated, central disc, which
-now looks like a simple box or capsule without arms. The original stock
-of five individuals has apparently degenerated to the form-value of a
-simple individual, a single person. Hence we may represent these two
-classes as a branch characterized as being without arms (Lipobrachia),
-equivalent to those which possess articulated arms. The first of these
-two classes, that of Sea-urchins (Echinida) takes its name from the
-numerous and frequently very large thorns which cover the hard shell,
-which is itself artistically built up of calcareous plates. (Fig. _C_,
-Plates VIII. and IX.) The fundamental form of the shell itself is a
-pentagonal pyramid. The Sea-urchins probably developed directly out of
-the group of Sea-stars. The different classes and orders of marine
-lilies and stars which are given in the following table, illustrate the
-laws of progress and differentiation in a striking manner. In each
-succeeding period of the earth's history we see the individual classes
-continually increasing in variety and perfection. (Gen. Morph. ii. Plate
-IV.)
-
-The history of three of these classes of Star-fish is very minutely
-recorded by numerous and excellently preserved fossils, but on the other
-hand, we know almost nothing of the historical development of the fourth
-class, that of the Sea-cucumbers (Holothuriae). These curious
-sausage-shaped Star-fish manifest externally a deceptive similarity to
-worms. (Fig. _D_, Plates VIII. and IX.) The skeletal structures in their
-skin are very imperfect, and hence no distinct remains of their
-elongated, cylindrical, worm-like body could be preserved in a fossil
-state. However, from the comparative anatomy of the Holothuriae, we can
-infer that they have arisen, by the softening of the cutaneous skeleton,
-from members of the class of Sea-urchins.
-
-From the Star-fish we turn to the fifth and most highly developed tribe
-of the invertebrate animals, namely, the phylum of Articulata, or those
-with _jointed feet_ (Arthropoda). As has already been remarked, this
-tribe corresponds to Linnaeus' class of Insects. It contains four
-classes: (1) the genuine six-legged Insects, or Flies; (2) the
-eight-legged Spiders; (3) the Centipedes, with numerous pairs of legs;
-and (4) the Crabs, or Crustacea, whose legs vary in number. The last
-class breathe water through gills, and may therefore be contrasted as
-the main-class of gill-breathing Arthropoda, or Gilled Insects
-(Carides), with the three first classes. The latter breathe air by means
-of peculiar wind-pipes, or tracheae, and may therefore appropriately be
-united to form the main-class of the trachea-breathing Arthropoda, or
-Tracheate Insects (Tracheata).
-
-In all animals with articulated feet, as the name indicates, the legs
-are distinctly articulated, and by this, as well as by the strong
-differentiation of the separate parts of the body, or metamera, they are
-sharply distinguished from Ringed worms, with which Baer and Cuvier
-classed them. They are, however, in every respect so like the Ringed
-worms that they can scarcely be considered altogether distinct from
-them. They, like the Ringed worms, possess a very characteristic form of
-the central nervous system, the so-called ventral marrow, which
-commences in a gullet-ring encircling the mouth. From other facts also,
-it is evident that the Arthropoda developed at a late period out of
-articulated worms. Probably either the Wheel Animalcules or the Ringed
-worms are their nearest blood relations in the Worm tribe. (Gen. Morph.
-ii. Plate V. pp. 85-102.)
-
-Now, although the derivation of the Arthropoda from ringed Worms may be
-considered as certain, still it cannot with equal assurance be
-maintained that the whole tribe of the former has arisen out of one
-branch of the latter. For several reasons seem to support the
-supposition that the Gilled Arthropods have developed out of a branch of
-articulated worms, different from that which gave rise to the Tracheate
-Arthropods. But on the whole it remains more probable that both
-main-classes have arisen out of one and the same group of Worms. In this
-case the Tracheate Insects--Spiders, Flies, and Centipedes--must have
-branched off at a later period from the gill-breathing Insects, or
-Crustacea.
-
-The pedigree of the Arthropoda can on the whole be clearly made out from
-the palaeontology, comparative anatomy, and ontogeny of its four
-classes, although here, as everywhere else, many details remain very
-obscure. Not until the history of the individual development of all the
-different groups has become more accurately known than it is at present,
-can this obscurity be removed. The history of the class of Gilled
-Insects, or Crabs (Carides), is at present that best known to us; they
-are also called encrusted animals (Crustacea), on account of the hard
-crust or covering of their body. The ontogeny of these animals is
-extremely interesting and, like that of Vertebrate animals, distinctly
-reveals the essential outlines of the history of their tribe, that is,
-their phylogeny. Fritz Mueller, in his work, "Fuer Darwin,"(16) which has
-already been referred to, has explained this remarkable series of facts
-in a very able manner.
-
-[Illustration: _Nauplius. Youth-form of six Crab-fish._ _Pl. X._
-
-  A. Limnetis.
-  B. Cyclops.
-  C. Lernacocera.
-  D. Lepas.
-  E. Sacculina.
-  F. Peneus.]
-
-[Illustration: _Adult form of the same six Crab-fish._ _Pl. XI._
-
-  A. Limnetis.
-  B. Cyclops.
-  C. Lernacocera.
-  D. Lepas.
-  E. Sacculina.
-  F. Peneus.]
-
-The common primary form of all Crabs, which in most cases is even now
-the first to develop out of the egg, is originally one and the same, the
-so-called _Nauplius_. This remarkable primaeval crab represents a very
-simple form of articulated animal, the body of which in general has the
-form of a roundish, oval, or pear-shaped disc, and has on its ventral
-side only three pairs of legs. The first of these is uncloven, the two
-subsequent pairs are forked. In front, above the mouth, lies a simple,
-single eye. Although the different orders of the Crustacean class differ
-very widely from one another in the structure of their body and its
-appendages, yet the early Nauplius form always remains essentially the
-same. In order to be convinced of this, let the reader look attentively
-at Plates X. and XI., a more detailed explanation of which is given in
-the Appendix. On Plate XI. we see the fully developed representatives of
-six different orders of Crabs, a Leaf-footed Crab (Limnetis, Fig. _A
-c_); a Stalked Crab (Lepas, Fig. _D c_); a Root Crab (Sacculina, Fig.
-_E c_); a Boatman Crab (Cyclops, Fig. _B c_); a Fish Louse (Lernaeocera,
-Fig. _C c_); and, lastly, a highly developed Shrimp (Peneus, Fig. _F
-c_). These six crabs vary very much, as we see, in the entire form of
-body, in the number and formation of the legs, etc. When, however, we
-look at the earliest stages, or "nauplius," of these six different
-classes, after they have crept out of the egg--those marked with
-corresponding letters on Plate X. (Fig. _A n-F n_)--we shall be
-surprised to find how much they agree. The different forms of Nauplius
-of these six orders differ no more from one another than would six
-different "good species" of one genus. Consequently, we may with
-assurance infer a common derivation of all those orders from a common
-Primaeval Crab, which was essentially like the Nauplius of the present
-day.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 7 Legions and 20 Orders of Crabs, or Crustacea._
-
-
-  -------------------------+--------------------------+----------------------+--------------
-     _Legions of the_      |     _Orders of the_      |    _Systema  Name_   |  _Name of a_
-      _Crustaceae._         |      _Crustaceae._        |    _of the Orders._  | _Genus as an_
-                           |                          |                      |  _example._
-  -------------------------+--------------------------+----------------------+--------------
-  I. ENTOMOSTRACA, _Lower Crustacea_, or Segmented Crabs (not passing through the
-                             actual Zoea form in youth).
-  ------------------------------------------------------------------------------------------
-
-  +I. Branchiopoda+         { 1. Primaeval Crabs         1. Archicarida         Nauplius
-  Gill-footed Crabs         { 2. Leaf-foot Crabs        2. Phyllopoda          Limnetis
-                            { 3. Trilobites             3. Trilobita           Paradoxides
-                            { 4. Water Fleas            4. Cladocera           Daphnia
-                            { 5. Bivalve Crabs          5. Ostracoda           Cypris
-
-
-  +II. Pectostraca+         { 6. Barnacle Crabs         6. Cirripedia          Lepas
-    Fixed Crabs             { 7. Root Crabs             7. Rhizocephala        Sacculina
-
-  +III. Copepoda+           { 8. Boatmen Crabs          8. Eucopepoda          Cyclops
-  Oar-footed Crabs          { 9. Fish Lice              9. Siphonostoma        Lernaeocera
-
-  +IV. Pantopoda+           {10. No-body Crabs         10. Pycnogonida         Nymphon
-   No-body Crabs            {
-
-  +V. Poecilopoda+          {11. Spear-tails           11.  Xiphosura          Limulus
-   Shield Crabs             {12. Giant Crabs           12.  Gigantostraca      Eurypterus
-
-  ------------------------------------------------------------------------------------------
-  II. MALACOSTRACA, _Higher Crustacea_, or Mailed Crabs (passing through the Zoea form
-                                     in youth).
-  ------------------------------------------------------------------------------------------
-
-  +VI. Podophthalma+        {13. Zoea Crabs            13. Zoepoda            Zoea
-  Stalk-eyed Mailed         {14. Split-legged Crabs    14. Schizopoda         Mysis
-  Crabs                     {15. Mouth-footed Crabs    15. Stomatopoda        Squilla
-                            {16. Ten-footed Crabs      16. Decapoda           Peneus
-
-  +VII. Edriophthalma+      {17. Cuma Crabs            17. Cumacea            Cuma
-   Mailed Crabs with        {18. Flea Crabs            18. Amphipoda          Gammarus
-    sessile eyes            {19. Wizard Crabs          19. Laemodipoda         Caprella
-                            {20. Louse Crabs           20. Isopoda            Oniscus
-
-        ----------------------------------------------------------------
-
-
-  Brachyura                                            Isopoda
-      |                                                   |
-      |                                    Laemodipoda     |
-      |                                        |          |
-  Anomura                                      |          |
-      |                                        |          |
-      |                                     Amphipoda     |
-      |                                        |          |
-      |                                        \-----v----/
-  Macrura                                           |
-  Decapoda  Stomatopoda                          Cumacea
-      |         |                            +Edriophthalma+
-      |         |                                   |
-      \----v----/                                   |
-           |                                        |
-           |                                        |
-           \---------------------------v------------/
-                                       |
-                                    Schizopoda
-                                  +Podophthalma+
-                                       |
-                                    Zoepoda
-                                +Malacostraca+
-  Gigantostraca                        |                 Rhizocephala
-         |                             |  Siphonostoma        |
-         |         Xiphosurae         Zoea      |          Cirripediae
-         |             |               |       |         +Pectostraca+
-         |             |               |       |              |
-         \------v------/               |       |              |
-                |                      |       |              |
-        +Poecilopoda+                  |       |              |
-                |            Nebaliae   |       |              |
-                |               |      |  Eucopepoda          |
-            Belinuroe           |      |  +Copepoda+          |     Pycnogonida
-                |               |      |       |              |     +Pantopoda+
-            Trilobita           |      |       |              |          |
-                |           Phyllopoda |       |  Ostracoda   |          |
-  Cladocerae     |               |      |       |      |       |          |
-      |         |               |      |       |      |       |          |
-      \-----------------v-------/      |       |      \---v---/          |
-                        |              |       |          |              |
-                 +Branchiopoda+        |       |          |              |
-                        |              |       |          |              |
-                        |              |       |          |              |
-                        \----------------------v-------------------------/
-                                               |
-                                            Nauplius
-                                               |
-                                          +Archicaridae+
-
-                                        (Articulated Worms)
-
-
-The pedigree on p. 177 will show how we may at present approximately
-conceive the derivation of the twenty orders of Crustacea enumerated on
-p. 176, from the common primary form of the Nauplius. Out of the
-Nauplius form--which originally existed as an independent genus--the
-five legions of lower Crabs developed as diverging branches in different
-directions, which in the systematic survey of the class are united as
-Segmented Crabs (Entomostraca). The higher division of Mailed Crabs
-(Malacostraca) have likewise originated out of the common Nauplius form.
-The Nebalia is still a direct form of transition from the Phyllopods to
-the Schizopods, that is, to the primary form of the stalk-eyed and
-sessile-eyed Mailed Crabs. The Nauplius at this stage gives rise to
-another larva form, the so-called Zoea, which is of great importance.
-The order of Schizopoda, those with cloven feet (Mysis, etc.), probably
-originated from this curious Zoea; they are at present still directly
-allied, through the Nebalia to the Phyllopoda, those with foliaceous
-feet. But of all living crabs the Phyllopods are the most closely allied
-to the original primary form of the Nauplius. Out of the Schizopoda the
-stalk-eyed and sessile-eyed Mailed Crabs, or Malacostraca, developed as
-two diverging branches in different directions: the former through
-shrimps (Peneus, etc.), the latter through the Cumacea (Cuma, etc.),
-which are still living and closely allied to the Schizopoda. Among those
-with stalked eyes is the river crab (cray-fish), the lobster, and the
-others with long tails, or the Macrura, out of which, in the chalk
-period, the short-tailed crabs, or Brachyura, developed by the
-degeneration of the tail. Those with sessile eyes divide into the two
-branches of Flea-crabs (Amphipoda) and Louse-crabs (Isopoda); among the
-latter are our common Rock-slaters and Wood-lice.
-
-The second main-class of Articulated animals, that of the Tracheata, or
-air-breathing Tracheate Insects[4] (Spiders, Centipedes, and Flies) did
-not develop until the beginning of the palaeolithic era, after the close
-of the archilithic period, because all these animals (in contrast with
-the aquatic crabs) are originally inhabitants of land. It is evident
-that the Tracheata can have developed only after the lapse of the
-Silurian period when terrestrial life first began. But as fossil remains
-of spiders and insects have been found, even in the carboniferous beds,
-we can pretty accurately determine the time of their origin. The
-development of the first Tracheate Insects out of gill-bearing
-Zoea-crabs, must have taken place between the end of the Silurian and
-the beginning of the coal period, that is, in the Devonian period.
-
-Gegenbaur, in his excellent "Outlines of Comparative Anatomy,"(21) has
-lately endeavoured to explain the origin of the Tracheata by an
-ingenious hypothesis. The system of tracheae, or air pipes, and the
-modifications of organization dependent upon it, distinguish Flies,
-Centipedes, and Spiders so much from other animals, that the conception
-of its first origin presents no inconsiderable difficulties to
-phylogeny. According to Gegenbaur, of all living Tracheate Insects, the
-Primaeval Flies, or Archiptera, are most closely allied to the common
-primary form of the Tracheata. These insects--among which we may
-especially mention the delicate Day flies (Ephemera), and the agile
-dragon-flies (Libellula)--in their earliest youth, as larvae, frequently
-possess _external tracheate gills_ which lie in two rows on the back of
-the body, and are shaped like a leaf or paint-brush. Similar leaf or
-paint-brush shaped organs are met with as real water-breathing organs or
-gills, in many crabs and ringed worms, and, moreover, in the latter as
-real dorsal appendages or limbs. The "tracheate gills," found in the
-larvae of many primaeval winged insects, must in all probability be
-explained as "_dorsal limbs_," and as having developed out of the
-corresponding appendages of the Annelida, or possibly as having really
-arisen out of similar parts in Crustacea long since extinct. The present
-tracheal respiration of the Tracheata developed at a later period out of
-respiration through the "tracheate gills." The tracheate gills
-themselves, however, have in some cases disappeared, and in others
-become transformed into the _wings_ of the Flies. They have disappeared
-entirely in the classes of Spiders and Centipedes, and these groups must
-accordingly be conceived of as degenerated or peculiarly developed
-lateral branches of the Fly class, which at an early period branched off
-from the common primary form of Flies; Spiders probably did so at an
-earlier period than Centipedes. Whether that common primary form of all
-Tracheata, which in my General Morphology I have named Protracheata, did
-develop directly out of genuine Ringed worms, or at first out of
-Crustacea of the Zoea form (Zoepoda, p. 177) will probably be settled at
-some future time by a more accurate knowledge and comparison of the
-ontogeny of the Tracheata, Crustacea, and Annelida. However, the root of
-the Tracheata, as well as that of the Crustacea, must in any case be
-looked for in the group of Ringed worms.
-
-The genuine Spiders (Arachnida) are distinguished from Flies by the
-absence of wings, and by four pairs of legs; but, as is distinctly seen
-in the Scorpion-spiders and Tarantulae, they, like Flies, possess in
-reality only three pairs of genuine legs. The apparent "fourth pair of
-legs" in spiders (the foremost) are in reality a pair of feelers. Among
-the still existing Spiders, there is a small group which is probably
-very closely allied to the common primary form of the whole class; this
-is the order of Scorpion-spiders, or Solifugae, (Solpuga, Galeodes), of
-which several large species live in Africa and Asia, and are dreaded on
-account of their poisonous bite. Their body consists--as we suppose to
-have been the case in the common ancestor of the Tracheata--of a head
-possessing several pairs of feelers like legs, of a thorax, to the three
-rings of which are attached three pairs of legs, and of a hinder body,
-or abdomen, consisting of many distinct rings. In the articulation of
-their body, the Solifugae are therefore in reality more closely related
-to flies than to other spiders. Out of the Devonian Primaeval Spiders,
-which were nearly related to the Solifugae of the present day, the Long
-Spiders, the Tailor Spiders, and the Round Spiders probably developed as
-three diverging branches.
-
-The _Long Spiders_ (Arthrogastres), in which the earlier articulation of
-body has been better preserved than in Round Spiders, appear to be the
-older and more original forms. The most important members of this
-sub-class are the scorpions, which are connected with the Solifugae
-through the Tarantella (or Phrynidae). The small book scorpions, which
-inhabit our libraries and herbariums, appear as a degenerate lateral
-branch from the true scorpions. Midway between the Scorpions and Round
-Spiders are the long-legged Tailor-spiders (Opiliones) which have
-possibly arisen out of a special branch of the Solifugae. The
-Pycnogonida, or No-body Crabs, and the Arctisca, or Bear Worms--still
-generally included among Long Spiders--must be completely excluded from
-the class of Spiders; the former belong to the Crustacea, the latter to
-Ringed worms.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 3 Classes and 17 Orders of the Tracheata._
-
-
-  ------------------+---------------------+----------------------+----------------------
-  _Classes of the_  | _Sub-Classes of the_|   _Order of the_     |   _Two Names of_
-    _Tracheata._    |     _Tracheata._    |     _Tracheata._     |_Genera as examples._
-  ------------------+---------------------+----------------------+----------------------
-                    {                     {  1. Scorpion spiders  { Solpuga
-                    {                     {    _Solifugae_         { Galeodes
-                    {                     {
-                    {                     {  2. Tarantella        { Phrynus
-                    {                     {    _Phrynida_         { Thelyphonus
-                    {         I.          {
-           I.       {     Long spiders    {  3. Scorpions         { Scorpio
-        =Spiders=   {    _Arthrogastres_  {    _Scorpioda_        { Buthus
-                    {                     {
-       +Arachnida+  {                     {  4. Book scorpions    { Obisium
-                    {                     {    _Pseudoscorpioda_  { Chelifer
-                    {                     {
-                    {                     {  5. Tailor spiders    { Phalangium
-                    {                     {    _Opilionida_       { Opilio
-                    {
-                    {
-                    {         II.         {  6. Spinning spiders  { Epeira
-                    {     Round spiders   {    _Araneae_           { Mygale
-                    {                     {                       {
-                    {    _Sphaerogastres_  {  7. Mites             { Sarcoptes
-                    {                     {    _Acarida_          { Demodex
-
-
-          II.       {          III.
-      =Centipedes=  {      Simple-footed  {  8. Simple-footed     { Scolopendra
-                    {       _Chilopoda_   {    _Chilopoda_        { Geophilus
-                    {                     {
-     +Scolopendria+ {          IV.        {  9. Double-footed     { Julus
-           or       {      Double-footed  {    _Diplopoda_        { Polydesmus
-       +Myriapoda+  {       _Diplopoda_   {
-
-
-                    {                     { 10. Primitive flies   { Ephemera
-                    {                     {    _Archiptera_       { Libellula
-                    {                     {
-                    {                     { 11. Gauze-wings       { Hemerobius
-                    {                     {    _Neuroptera_       { Phryganea
-                    {           V.        {
-                    {        Chewing      { 12. Straight-wings    { Locusta
-                    {     _Masticantia_   {    _Orthoptera_       { Forficula
-                    {                     {
-          III.      {                     { 13. Beetles           { Cicindela
-         =Flies=    {                     {    _Coleoptera_       { Melolontha
-                    {                     {
-       +Hexapoda+   {                     { 14. Bee-wings         { Apis
-                    {                     {    _Hymenoptera_      { Formica
-                    {
-                    {
-                    {                     { 15. Bugs              { Aphis
-                    {          VI.        {    _Hemiptera_        { Cimex
-                    {        Sucking      {
-                    {      _Sugentia_     { 16. Two-wings         { Culex
-                    {                     {    _Diptera_          { Musca
-                    {                     {
-                    {                     { 17. Butterflies       { Bombyx
-
-        ----------------------------------------------------------------
-
-                                Butterflies
-                               _Lepidoptera_
-                                     |
-                     Bees            |           Two-wings
-                 _Hymenoptera_       |           _Diptera_
-                       |             |               |
-                       |             |               |
-      Beetles          |             |               |             Bugs
-  _Coleoptera_         \-------v-----/               |          _Hemiptera_
-        |                      |                     |              |
-        |                 Gauze wings                |              |
-  Straight-wings          _Neuroptera_               \-------v------/
-  _Orthoptera_                 |                             |
-        |                      |                             |
-        |                      |                             |
-        \----------------------v-----------------------------/
-
-                                         Primaeval Flies
-                                          _Archiptera_
-                                               |
-                                  Scorpions    |             Double-footed
-                                 _Scorpioda_   |              _Diplopoda_
-             Tailor Spiders            |       |                   |
-              _Opiliones_              |       |                   |
-                   |  Book Scorpions   |       |                   |
-       Mites       | _Pseudoscorpioda_ |       |                   |
-      _Acarida_    |       |           |       |                   |
-          |        |       \-----v-----/       |                   |
-          |        |             |             |                   |
-          |        |         Tarantella        |                   |
-   Weaving Spiders |         _Phrynida_        |              Simple-footed
-      _Araneae_     |             |             |               _Chilopoda_
-          |        |             |             |               =Centipedes=
-          |        |             |             |               +Myriapoda+
-          \-------------v--------/             |                   |
-                        |                      |                   |
-                 Scorpion Spiders              |                   |
-                   _Solifugae_                  |                   |
-                    =Spiders.=                 |                   |
-                   +Arachnida+                 |                   |
-                        |                      |                   |
-                        |                    =Flies=               |
-                        |               +Insecta Hexapoda+         |
-                        |                      |                   |
-                        |                      |                   |
-                        \--------------------v---------------------/
-                                             |
-                               Primary Air-breathing Arthropods
-                                        _Protracheata_
-                                             |
-                                             |
-                                      Articulated Worms
-                                        _Coelminthes_
-
-Fossil remains of Long Spiders are found in the Coal. The second
-sub-class of the Arachnida, the _Round Spiders_ (Sphaerogastres), first
-appear in the fossil state in the Jura, that is, at a very much later
-period. They have developed out of a branch of the Solifuga, by the
-rings of the body becoming more and more united with one another. In the
-true _Spinning Spiders_ (Araneae), which we admire on account of their
-delicate skill in weaving, the union of the joints of the trunk, or
-metamera, goes so far, that the trunk now consists of only two pieces,
-of a head-breast (cephalo-thorax) with jaws, feelers, and four pairs of
-legs, and of a hinder body without appendages, where the spinning warts
-are placed. In _Mites_ (Acarida), which have probably arisen by
-degeneration (especially by parasitism) out of a lateral branch of
-Spinning Spiders, even these two trunk pieces have become united and now
-form an unsegmented mass.
-
-The class of _Scolopendria_, _Myriapoda_, or Centipedes, the smallest
-and poorest in forms of the four classes of Arthropoda, is characterized
-by a very elongated body, like that of a segmented Ringed worm, and
-often possesses more than a hundred pairs of legs. But these animals
-also originally developed out of a six-legged form of Tracheata, as is
-distinctly proved by the individual development of the millipede in the
-egg. Their embryos have at first only three pairs of legs, like genuine
-insects, and only at a later period do the posterior pairs of legs bud,
-one by one, from the growing rings of the hinder body. Of the two orders
-of Centipedes (which in our country live under barks of trees, in moss,
-etc.) the round, _double-footed_ ones (Diplopoda) probably did not
-develop until a later period out of the older flat, _single-footed_ ones
-(Chilopoda), by successive pairs of rings of the body uniting together.
-Fossil remains of the Chilopoda are first met with in the Jura period.
-
-The third and last class of the Arthropoda breathing through tracheae, is
-that of the _Flies_, or _Insects_, in the narrow sense of the word
-(Insecta, or Hexapoda), the largest of all classes of animals, and next
-to that of Mammalia, also the most important. Although Flies develop a
-greater variety of genera and species than all other animals taken
-together, yet these are all in reality only superficial variations of a
-single type, which is entirely and constantly preserved in its essential
-characteristics. In all Flies the three divisions of the trunk--head,
-breast (thorax), and hinder body are quite distinct. The _hinder body_,
-or _abdomen_, as in the case of spiders, has no articulated appendages.
-The central division, the _breast_ or _thorax_, has on its ventral side
-three pairs of legs, on its back _two pairs of wings_. It is true that,
-in very many Flies, one or both pairs of wings have become reduced in
-size or have even entirely disappeared; but the comparative anatomy of
-Flies distinctly shows that this deficiency has arisen only gradually by
-the degeneration of the wings, and that all the Flies existing at
-present are derived from a common, primary Fly, which possessed three
-pairs of legs and two pairs of wings. (Compare p. 256.) These wings,
-which so strikingly distinguish Flies from all other Arthropoda,
-probably arose, as has been already shown, out of the tracheate gills
-which may still be observed in the larvae of the ephemeral flies
-(Ephemera) which live in water.
-
-The head of Flies universally possesses, besides the eyes, a pair of
-articulated feelers, or antennae, and also three jaws upon each side of
-the mouth. These _three pairs of jaws_, although they have arisen in all
-Flies from the same original basis, by different kinds of adaptation,
-have become changed to very varied and remarkable forms in the various
-orders, and are therefore employed for distinguishing and characterizing
-the main divisions of the class. In the first place, we may distinguish
-two main divisions, namely, Flies with _chewing_ mandibles (Masticantia)
-and Flies with _sucking_ mouths (Sugentia). On a closer examination each
-of these two divisions may again be divided into two sub-groups. Among
-chewing Flies, or Masticantia, we may distinguish the biting and the
-licking ones. _Biting flies_ (Mordentia) comprise the most ancient and
-primaeval winged Flies, the gauzy-winged (Neuroptera), straight-winged
-(Orthoptera), and beetles (Coleoptera). _Licking flies_ (Lambentia) are
-represented by the one order of skin-winged (Hymenoptera) Flies. We
-distinguish two groups of _Sucking Flies_, or Sugentia, namely, those
-which prick and those which sip. There are two orders of pricking Flies
-(Pungentia), those with half wings (Hemiptera) and gnats and blow-flies
-(Diptera); butterflies are the only _sipping_ Flies (Sorbentia),
-Lepidoptera.
-
-Biting Flies, and indeed the order of _Primaeval Flies_ (Archiptera, or
-Pseudoneuroptera) are nearest akin to the still living Flies, and
-include the most ancient of all Flies, the primary forms of the whole
-class (hence also those of all Tracheata). Among them are, first of all,
-the Ephemeral Flies (Ephemera) whose larvae which live in water, in all
-probability still show us in their tracheae-gills the organs out of which
-the wings of Flies were originally developed. This order further
-contains the well known dragon-flies, or Libellula, the wine-glass sugar
-mites (Lepisma), the hopping Flies with bladder-like feet (Physopoda),
-and the dreaded Termites, fossil remains of which are found even in
-coal. The order of Gauze-winged Flies (Neuroptera), probably developed
-directly out of the primaeval Flies, which differ from them only by their
-perfect series of transformations. Among them are the gauze-flies
-(Planipennia), caddis-flies (Phryganida), and fan-flies (Strepsiptera).
-Fossil Flies, which form the transition from the primaeval Flies
-(Libellula) to the gauze-winged (Sialidae), are found even in coal
-(Dictyophylebia).
-
-The order of _Straight-winged Flies_ (Orthoptera) developed at an early
-period out of another branch of the primaeval Flies by differentiation of
-the two pairs of wings. This division is composed of one group with a
-great variety of forms--cockroaches, grasshoppers, crickets, etc.
-(Ulonata)--and of a smaller group consisting only of the well-known
-earwigs (Labidura), which are characterised by nippers at the hinder end
-of their bodies. Fossil remains of cockroaches, as well as of crickets
-and grasshoppers, have been found in coal.
-
-Fossil remains of the fourth order of Biting Flies, _beetles_
-(Coleoptera) likewise occur in coal. This extremely comprehensive
-order--the favourite one of amateurs and collectors--shows more clearly
-than any other what infinite variety of forms can be developed
-externally by adaptation to different conditions of life, without the
-internal structure and the original form of the body being in any way
-essentially changed. Beetles have probably developed out of a branch of
-the straight-winged Flies, from which they differ only in their
-transformations (larva, pupa, etc.).
-
-The one order of _Licking Flies_, namely, the interesting group of the
-_Bees_, or _Skin-winged Flies_ (Hymenoptera), is closely allied to the
-four orders of biting Flies. Among them are those Flies which have risen
-to such an astonishing degree of mental development, of intellectual
-perfection, and strength of character, by their extensive division of
-labour, formation of communities and states, and surpass in this not
-merely most invertebrate animals, but even most animals in general. This
-may be said especially of all ants and bees, also of wasps, leaf-wasps,
-wood-wasps, gall-wasps, etc. They are first met with in a fossil state
-in the oolites, but they do not appear in greater numbers until the
-tertiary period. Probably these insects developed either out of a branch
-of the primaeval Flies or the gauze-winged Flies.
-
-Of the two orders of _Pricking Flies_ (Hemiptera and Diptera), that
-containing the _Half-winged Flies_ (Hemiptera), also called Beaked Flies
-(Rhynchota), is the older of the two. It includes three sub-orders,
-viz., the leaf-lice (Homoptera), the bugs (Heteroptera), and lice
-(Pediculina). Fossil remains of the first two classes are found in the
-oolites; but an ancient Fly (Eugereon) is found in the Permian system,
-and seems to indicate the derivation of the Hemiptera from the
-Neuroptera. Probably the most ancient of the three sub-orders of the
-Hemiptera are the Homoptera, among which, besides the actual leaf-lice,
-are the shield-lice, leaf-fleas, and leaf-crickets, or Cicadae. Lice have
-probably developed out of two different branches of Homoptera, by
-continued degeneration (especially by the loss of wings); bugs, on the
-other hand, by the perfecting and differentiation of the two pairs of
-wings.
-
-The second order of _pricking flies_, namely, the _Two-winged Flies_
-(Diptera), are also found in a fossil state in the oolites, together
-with Half-winged Flies; but they probably developed out of the Hemiptera
-by the degeneration of the hind wings. In Diptera the fore wings alone
-have remained perfect. The principal portion of this order consists of
-the elongated gnats (Nemocera) and of the compact blow-flies and
-house-flies (Brachycera), the former of which are probably the older of
-the two. However, remains of both are found in the oolitic period. The
-two small groups of lice-flies (Pupipara) forming chrysales, and the
-hopping-fleas (Aphaniptera), probably developed out of the Diptera by
-degeneration resulting from parasitism.
-
-The eighth and last order of Flies, and at the same time the only one
-with mouth-parts adapted to sipping liquids, consists of _moths_ and
-_butterflies_ (Lepidoptera). This order appears, in several
-morphological respects, to be the most perfect class of Flies, and
-accordingly was the last to develop. For we only know of fossil remains
-of this order from the tertiary period, whereas the three preceding
-orders extend back to the oolites, and the four biting orders even to
-the coal period. The close relationship between some moths (Tineae) and
-(Noctuae), and some caddis-flies (Phryganida) renders it probable that
-butterflies have developed from this group, that is, out of the order of
-Gauze-winged Flies, or Neuroptera.
-
-The whole history of Flies, and, moreover, the history of the whole
-tribe of Arthropoda, essentially confirms the great laws of
-differentiation and perfecting which, according to Darwin's theory of
-selection, must be considered as the necessary results of Natural
-Selection. The whole tribe, so rich in forms, begins in the Archilithic
-period with the class of _Crabs_ breathing by gills, and with the lowest
-_Primaeval Crabs_, or Archicaridae. The form of these Primaeval Crabs,
-which were developed out of segmented worms, is still approximately
-preserved by the remarkable _Nauplius_, in the common larval stage of so
-many Crabs. Out of the Nauplius, at a later period, the curious Zoea was
-developed, which is the common larval form of all the higher or mailed
-crabs (Malacostraca), and, at the same time, possibly of that Arthopod
-which at first breathed through tracheae, and became the common ancestor
-of all _Tracheata_. This Devonian ancestor, which must have originated
-between the end of the Silurian and the beginning of the Coal period,
-was probably most closely related to the still living Primaeval Flies, or
-_Archiptera_. Out of these there developed, as the main tribe of the
-Tracheata, the class of Flies, from the lowest stage of which the
-_spiders_ and _centipedes_ separated as two diverging branches.
-Throughout a long period there existed only the four biting orders of
-Flies--the Primaeval flies, Gauze-wings, Straight-wings, and the Beetles,
-the first of which is probably the common primary form of the three
-others. It was only at a much later period that the Licking, Pricking,
-and Sipping flies developed out of the Biting ones, which retained the
-original form of the three pairs of jaws most distinctly. The following
-table will show once more how these orders succeeded one another in the
-history of the earth.
-
-
-CLASSIFICATION OF FLIES.
-
-                    {                 { 1. Primaeval winged   { M.I.  }
-                    {                 {    _Archiptera_      { A.A.  }
-                    {                 {                              }
-                    {      I.         { 2. Gauze-winged      { M.C.  }
-        A.          {  Biting Flies   {    _Neuroptera_      { A.A.  }
-                    {                 {                              }
-      =Flies=       {  _Mordentia_    { 3. Straight-winged   { M.I.  }
-  =with Chewing=    {                 {    _Orthoptera_      { A.D.  }
-     =Mouths=       {                 {                              }
-                    {                 { 4. Beetles           { M.C.  }
-  +Masticantia+     {                 {    _Coleoptera_      { A.D.  }
-                    {
-                    {
-                    {      II.        { 5. Skin-winged       { M.C.  }
-                    {  Licking Flies  {    _Hymenoptera_     { A.A.  }
-                    {   _Lambentia_   {                              }
-                                                                     }
-                                                                     }
-                    {                 { 6. Half-winged       { M.I.  }
-                    {      III.       {    _Hemiptera_       { A.A.  }
-        B.          {  Stinging Flies {                              }
-      =Flies=       {                 { 7. Tway-flies        { M.C.  }
-  =with Sucking=    {   _Pungentia_   {    _Diptera_         { A.D.  }
-     =Mouths=       {
-                    {
-   +Sugentia+       {      IV.        { 8. Butterflies       { M.C.  }
-                    {  Sipping Flies  {    _Lepidoptera_     { A.A.  }
-                    {                 {                      {       }
-                    {   _Sorbentia_   {                      {       }
-
-
-   _Note._--The difference in the metamorphosis or transformation and in
-   the development of the wings of the eight individual orders of Flies
-   is also specified by the following letters: M.I. = Imperfect
-   Metamorphosis. M.C. = Perfect Metamorphosis. (Compare Gen. Morph. ii.
-   p. 99.) A.A. = Equal wings (fore and hinder wings are the same, or
-   differ but little). A.D. = Unequal wings (fore and hinder wings very
-   different in structure and texture, occasioned by strong
-   differentiation).
-
-
-
-
-CHAPTER XX.
-
-PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-III. VERTEBRATE ANIMALS.
-
-
-  The Records of the Creation of Vertebrate Animals (Comparative
-  Anatomy, Embryology, and Palaeontology).--The Natural System of
-  Vertebrate Animals.--The Four Classes of Vertebrate Animals,
-  according to Linnaeus and Lamarck.--Their increase to Nine
-  Classes.--Main Class of the Tube-hearted, or Skull-less Animals
-  (the Lancelet).--Blood Relationship between the Skull-less Fish
-  and the Tunicates.--Agreement in the Embryological Development
-  of Amphioxus and Ascidiae.--Origin of the Vertebrate Tribe out of
-  the Worm Tribe.--Main Class of Single-nostriled, or
-  Round-mouthed Animals (Hag and Lampreys).--Main Class of
-  Anamnionate Animals, devoid of Amnion.--Fishes (Primaeval Fish,
-  Cartilaginous Fish, Osseous Fish).--Mud-fish, or Dipneusta.--Sea
-  Dragons, or Halisauria.--Frogs and Salamanders, or Amphibia
-  (Mailed Amphibia, Naked Amphibia).--Main Class of Amnionate
-  Animals, or Amniota.--Reptiles (Primary Reptiles, Lizards,
-  Serpents, Crocodiles, Tortoises, Flying-Reptiles, Dragons,
-  Beaked Reptiles).--Birds (Feather-tailed, Fan-tailed,
-  Bush-tailed).
-
-
-Not one of the natural groups of organisms--which, we have designated as
-tribes, or phyla, on account of the blood-relationship of all the
-species included in them--is of such great and exceeding importance as
-the tribe of Vertebrate Animals. For, according to the unanimous opinion
-of all zoologists, man also is a member of the tribe; and his whole
-organization and development cannot possibly be distinguished from that
-of other Vertebrate animals. But as from the individual history of
-human development, we have already recognized the undeniable fact that,
-in developing out of the egg, man at first does not differ from other
-Vertebrate animals, and especially from Mammals, we must necessarily
-come to the conclusion, in regard to the palaeontological history of his
-development, that man has, historically, actually developed out of the
-lower Vertebrata, and that he is directly derived from lower mammals.
-This circumstance, together with the many high interests which, in other
-respects, entitle the Vertebrata to more consideration than other
-organisms, justifies us in examining the pedigree of the Vertebrata and
-its expression in the natural system, with special care.
-
-Fortunately, the records of creation, which must in all cases be our
-guide in establishing pedigrees, are especially complete in this
-important animal tribe, from which our own race has arisen. Even at the
-beginning of our century Cuvier's comparative anatomy and palaeontology,
-and Baer's ontogeny of the Vertebrate animals, had brought us to a high
-level of accurate knowledge on this matter. Since then it is especially
-due to Johannes Mueller's and Rathke's investigations in comparative
-anatomy, and most recently to those of Gegenbaur and Huxley, that our
-knowledge of the natural relationships among the different groups of
-Vertebrata has become enlarged. It is especially Gegenbaur's classical
-works, penetrated as they are throughout with the fundamental principles
-of the Theory of Descent, which have demonstrated that the material of
-comparative anatomy receives its true importance and value only by the
-application of the Theory of Descent, and this in the case of all
-animals, but especially in that in the Vertebrate tribe. Here, as
-everywhere else, analogies must be traced to Adaptation, homologies to
-Transmission by Inheritance. When we see that the limbs of the most
-different Vertebrata, in spite of their exceedingly different external
-forms, nevertheless possess essentially the same internal structure;
-when we see that in the arm of a man and ape, in the wing of a man or a
-bird, in the breast fins of whales and sea-dragons, in the fore-legs of
-hoofed animals and frogs, the same bones always lie in the same
-characteristic position, articulation and connection--we can only
-explain this wonderful agreement and homology by the supposition of a
-common transmission by inheritance from a single primary form. On the
-other hand, the striking differences of these homologous bodily parts
-proceed from adaptation to different conditions of existence. (Compare
-Plate IV.)
-
-Ontogeny, or the individual history of development, like comparative
-anatomy, is of especial importance to the pedigree of the Vertebrata.
-The first stages of development arising out of the egg are essentially
-identical in all Vertebrate animals, and retain their agreement the
-longer, the nearer the respective Vertebrate animal forms, when fully
-developed, stand to one another in the natural system, that is, in the
-pedigree. How far this agreement of germ forms, or embryos, extends,
-even in the most highly developed Vertebrate animals, I have already had
-occasion to explain (vol i. pp. 306-309). The complete agreement in form
-and structure, for example, in the embryos of a man and a dog, of a bird
-and a tortoise, existing in the stages of development represented on
-Plates II. and III., is a fact of incalculable importance, and furnishes
-us with the most important data for the construction of their pedigree.
-
-Finally, the palaeontological records of creation are also of especial
-value in the case of these same Vertebrate animals; for their fossil
-remains belong for the most part to the bony skeleton, a system of
-organs which is of the utmost importance for understanding their general
-organization. It is true that here, as in all other cases, the fossil
-records are exceedingly imperfect and incomplete, but more important
-remains of extinct Vertebrate animals have been preserved in a fossil
-state, than of most other groups of animals; and single fragments
-frequently furnish the most important hints as to the relationship and
-the historical succession of the groups.
-
-The name of _Vertebrate Animals_ (Vertebrata), as I have already said,
-originated with the great Lamarck, who towards the end of the last
-century comprised under this name, Linnaeus' four higher classes of
-animals, viz. Mammals, Birds, Amphibious animals, and Fishes, Linnaeus'
-two lower classes, Insects and Worms, Lamarck contrasted to the
-Vertebrata as _Invertebrata_, later also called _Evertebrata_.
-
-The division of the Vertebrata into the four classes above named was
-retained also by Cuvier and his followers, and in consequence by many
-zoologists down to the present day. But in 1822 Blanville, the
-distinguished anatomist, found out by comparative anatomy--which Baer did
-almost at the same time from the ontogeny of Vertebrata--that Linnaeus'
-class of Amphibious animals was an unnatural union of two very different
-classes. These two classes were separated as early as 1820, by Merrin,
-as two main groups of Amphibious animals, under the names of Pholidota
-and Batrachia. The _Batrachia_, which are at present (in a restricted
-sense) called Amphibious animals, comprise Frogs, Salamanders, gilled
-Salamanders, Caecilia, and the extinct Labyrinthodonta. Their entire
-organization is closely allied to that of Fishes. The _Pholidota_, or
-Reptiles, on the other hand, are much more closely allied to Birds. They
-comprise lizards, serpents, crocodiles, and tortoises, and the groups of
-the mesolithic Dragons, Flying reptiles, etc.
-
-In conformity with this natural division of Amphibious animals into two
-classes, the whole tribe of Vertebrate animals was divided into two main
-groups. The first main group, containing Amphibious animals and Fishes,
-breathe throughout their lives, or in early life, by means of gills, and
-are therefore called _gilled Vertebrata_ (Branchiata, or Anallantoida).
-The second main group--Reptiles, Birds, and Mammals--breathe at no
-period of their lives through gills, but exclusively through lungs, and
-hence may appropriately be called Gill-less, or _Vertebrata with lungs_
-(Abranchiata, or Allantoida). However correct this distinction may be,
-still we cannot remain satisfied with it if we wish to arrive at a true
-natural system of the vertebrate tribe, and at a right understanding of
-its pedigree. In this case, as I have shown in my General Morphology, we
-are obliged to distinguish three other classes of Vertebrate animals, by
-dividing what has hitherto been regarded as the class of fishes into
-four distinct classes. (Gen. Morph. vol. ii. Plate VII. pp. 116-160.)
-
-The first and lowest of these classes comprises the _Skull-less_ animals
-(Acrania), or animals with _tubular hearts_ (Leptocardia), of which only
-one representative now exists, namely, the remarkable little Lancelet
-(Amphioxus lanceolatus). Nearly allied to this is the second class, that
-of the _Single-nostriled_ animals (Monorrhina), or _Round-mouthed_
-animals (Cyclostoma), which includes the Hags (Myxinoida) and Lampreys
-(Petromyzonta). The third class contains only the genuine Fish (Pisces):
-the Mud-fishes (Dipneusta) are added to these as a fourth class, and
-form the transition from Fish to Amphibious animals. This distinction,
-which, as will be seen immediately, is very important for the genealogy
-of the Vertebrate animals, increases the original number of Vertebrate
-classes from four to eight.
-
-In most recent times a ninth class of Vertebrata has been added to these
-eight classes. Gegenbaur's recently published investigations in
-comparative anatomy prove that the remarkable class of _Sea-dragons_
-(Halisauria), which have hitherto been included among Reptiles, must be
-considered quite distinct from these, and as a separate class which
-branched off from the Vertebrate stock, even before the Amphibious
-animals. To it belong the celebrated large Ichthyosauri and Plesiosauri
-of the oolitic and chalk periods, and the older Simosauri of the Trias
-period, all of which are more closely allied to Fish than to Amphibious
-animals.
-
-These nine classes of Vertebrate animals are, however, by no means of
-the same genealogical value. Hence we must divide them, as I have
-already shown in the Systematic Survey on p. 133, into four distinct
-main-classes or tribes. In the first place, the three highest classes,
-Mammals, Birds, and Reptiles, may be comprised as a natural main-class
-under the name of _Amnion animals_ (Amnionata). The _Amnion-less
-animals_ (Anamnionata), naturally opposed to them as a second
-main-class, include the four classes of Batrachians, Sea-dragons,
-Mud-fish, and Fishes. The seven classes just named, the Anamnionata as
-well as the Amnionata, agree among one another in numerous
-characteristics, which distinguish them from the two lowest classes
-(the single-nostriled and tubular-hearted animals). Hence we may unite
-them in the natural main group of _Double-nostriled_ animals
-(Amphirrhina). Finally, these Amphirrhina on the whole are much more
-closely related to those animals with round mouths or single nostrils
-than to the skull-less or tube-hearted animals. We may, therefore, with
-full justice class the single and double-nostriled animals into one
-principal main group, and contrast them as _animals with skulls_
-(Craniota), or _bulbular hearts_ (Pachycardia), to the one class of
-_skull-less animals_, or animals with _tubular hearts_. This
-classification of the Vertebrate animals proposed by me renders it
-possible to obtain a clear survey of the nine classes in their most
-important genealogical relations. The systematic relationship of these
-groups to one another may be briefly expressed by the following table.
-
-
-          A.
-  =Skull-less Animals=                                     1. Tubular hearts 1. Leptocardia
-      (+Acrania+)
-
-                      { _a._ Single nostriled
-                      {      animals                     { 2. Round-mouths   2. Cyclostoma
-          B.          {    _Monorrhina_                  {
-     =Animals with=   {
-       =Skulls=       { b. Double     {                  { 3. Fish           3. Pisces
-    (+Craniota+)      { nostriled     { I. Non-Amnionate { 4. Mud-fish       4. Dipneusta
-                      { animals       { Anamnia          { 5. Sea-dragons    5. Halisauria
-         or           {               {                  { 6. Batrachians    6. Amphibia
-                      { _Amphirrhina_ {
-     =Thick Hearts=   {               { II. Amnionate.   { 7. Reptiles       7. Reptilia
-    (+Pachycardia+)   {               { Amniota          { 8. Birds          8. Aves
-                      {               {                  { 9. Mammals        9. Mammalia
-
-
-The only one representative of the first class, the small _lanceolate
-fish_, or Lancelet (Amphioxus lanceolatus) (Plate XIII. Fig. _B_),
-stands at the lowest stage of organization of all the Vertebrate
-animals known to us. This exceedingly interesting and important animal,
-which throws a surprising light upon the older roots of our pedigree, is
-evidently the last of the Mohicans--the last surviving representative of
-a lower class of Vertebrate animals, very rich in forms, and very highly
-developed during the primordial period, but which unfortunately could
-leave no fossil remains on account of the absence of all solid skeleton.
-The Lancelet still lives widely distributed in different seas; for
-instance, in the Baltic, North Sea, and Mediterranean, where it
-generally lies buried in the sand on flat shores. The body, as the name
-indicates, has the form of a narrow lanceolate leaf, pointed at both
-extremities. When full grown it is about two inches long, of a white
-colour and semi-transparent. Externally, the little lanceolate animal is
-so little like a vertebrate animal that Pallas, who first discovered it,
-regarded it as an imperfect naked snail. It has no legs, and neither
-head, skull, nor brain. Externally, the fore end of the body can be
-distinguished from the hinder end only by the open mouth. But still the
-Amphioxus in its internal structure possesses those most important
-features, which distinguish all Vertebrate animals from all Invertebrate
-animals, namely, the spinal rod and spinal marrow. The _spinal rod_
-(Chorda dorsalis) is a straight, cylindrical, cartilaginous staff,
-pointed at both ends, forming the central axis of the internal skeleton,
-and the basis of the vertebral column. Directly above the spinal rod, on
-its dorsal side, lies the _spinal marrow_ (medulla spinalis), likewise
-originally a straight but internally hollow cord, pointed at both ends.
-This forms the principal piece and centre of the nervous system in all
-Vertebrate animals. (Compare above vol. i. p. 303.) In all Vertebrate
-animals without exception, man included, these important parts of the
-body during the embryological development out of the egg, originally
-begin in the same simple form, which is retained throughout life by the
-Amphioxus. It is only at a later period that the brain develops by the
-expansion of the fore end of the spinal marrow, and out of the spinal
-rod the skull which encloses the brain. As these two important organs do
-not develop at all in the Amphioxus, we may justly call the class
-represented by it, _Skull-less animals_ (Acrania), in opposition to all
-the others, namely, to the _animals with skulls_ (Craniota). The
-Skull-less animals are generally called _tubular-hearted_ (Leptocardia),
-because a centralized heart does not as yet exist, and the blood is
-circulated in the body by the contractions of the tubular blood-vessels
-themselves. The Skulled animals, which possess a centralized,
-thick-walled, bulb-shaped heart, ought then by way of contrast to be
-called _bulbular-hearted_ animals (Pachycardia).
-
-[Illustration: _Ascidia (A.) and Amphioxus (B.)_ Pl. XII.
-
-  E. Haeckel del.       Legesse sc.]
-
-Animals with skulls and central hearts evidently developed gradually in
-the later primordial period out of those without skulls and with tubular
-hearts. Of this the ontogeny of skulled animals leaves no doubt. But
-whence are these same skull-less animals derived? It is only very lately
-that an exceedingly surprising answer has been given to this important
-question. From Kowalewsky's investigations, published in 1867, on the
-individual development of the Amphioxus and the adhering Sea-squirts
-(Ascidia) belonging to the class of mantled animals (Tunicata), it has
-been proved that the ontogenies of these two entirely different looking
-animal-forms agree in the first stage of development in a most
-remarkable manner. The freely swimming larvae of the Ascidians (Plate
-XII. Fig. _A_) develop the undeniable beginning of a spinal marrow (Fig.
-5 _g_) and of a spinal rod (Fig. 5 _c_), and this moreover in entirely
-the same way as does the Amphioxus. (Plate XIII. Fig. _B_.) It is true
-that in the Ascidians these most important organs of the Vertebrate
-animal-body do not afterwards develop further. The Ascidians take on a
-retrograde transformation, become attached to the bottom of the sea, and
-develop into shapeless lumps, which when looked upon externally would
-scarcely be supposed to be animals. (Plate XIII. Fig. _A_.) But the
-spinal marrow, as the beginning of the central nervous system, and the
-spinal rod, as the first basis of the vertebral column, are such
-important organs, so exclusively characteristic of Vertebrate animals,
-that we may from them with certitude infer the true blood relationship
-of Vertebrate with Tunicate animals. Of course we do not mean to say by
-this, that Vertebrate animals are derived from Tunicate animals, but
-merely that both groups have arisen out of a common root, and that the
-Tunicates, of all the Invertebrata, are the nearest blood relations of
-the Vertebrates. It is quite evident that genuine Vertebrate animals
-developed progressively during the primordial period (and the skull-less
-animals first) out of a group of worms, from which the degenerate
-Tunicate animals arose in another and a retrograde direction. (Compare
-the more detailed explanation of Plates XII. and XIII. in the Appendix.)
-
-Out of the Skull-less animals there developed, in the first instance, a
-second low class of Vertebrate animals, which still stands far below
-that of fish, and which is now represented only by the Hags (Myxinoida)
-and Lampreys (Petromyzonta). This class also, on account of the absence
-of all solid parts, could, unfortunately, as little as the Skull-less
-animals leave fossil remains. From its whole organization and ontogeny
-it is quite evident that it represents a very important intermediate
-stage between the Skull-less animals and Fishes, and that its few still
-existing members are only the last surviving remains of a probably very
-highly developed animal group which existed towards the end of the
-primordial period. On account of the curious mouth possessed by the Hags
-and Lampreys, which they use for sucking, the whole class is usually
-called _Round-mouthed_ animals (Cyclostoma). The name of
-_Single-nostriled_ animals (Monorrhina) is still more characteristic.
-For all Cyclostoma possess a simple, single nasal tube, whereas, in all
-other Vertebrate animals (with the exception of the Amphioxus) the nose
-consists of two lateral halves, a right and a left nostril. We are
-therefore enabled to comprise these latter (Anamnionata and Amnionata)
-under the heading, _double-nostriled_ animals (Amphirrhina). All the
-Amphirrhina possess a fully developed jaw-skeleton (upper and under
-jaw), whereas it is completely wanting in the Monorrhina.
-
-Apart also from the peculiar nasal formation, and the absence of jaws,
-the Single-nostriled animals are distinguished from those with double
-nostrils by many peculiarities. Thus they want the important sympathetic
-nervous system, and the spleen which the Amphirrhina possess. Of the
-swimming bladder, and the two pairs of legs--which all double-nostriled
-animals have, at least in their embryonic conditions--not a trace exists
-in the Single-nostriled animals, which is the case also in the
-Skull-less animals. Hence, we are surely justified in completely
-separating the Monorrhina, as we have separated the Skull-less animals,
-from the Fishes, with which they have hitherto been erroneously classed.
-
-[Illustration: _Ascidia (A.) and Amphioxus (B.)_ Pl. XIII.
-
-  E. Haeckel del.        Lagesse sc.]
-
-We owe our first accurate knowledge of the Monorrhina, or Cyclostoma, to
-the great zoologist, Johannes Mueller of Berlin; his classical work on
-the "Comparative Anatomy of the Myxinoida" forms the foundation of our
-modern views on the structure of the Vertebrate animals. He
-distinguished two distinct groups among the Cyclostoma, which we shall
-consider as sub-classes.
-
-The first sub-class consists of the Hags (Hyperotreta, or Myxinoida).
-They live in the sea as parasites upon other fish, into whose skin they
-penetrate (Myxine, Bdellostoma). Their organ of hearing has only one
-annular canal, and their single nasal tube penetrates the palate. The
-second sub-class, that of Lampreys, or Prides (Hyperoartia, or
-Petromyzontia) is more highly developed. It includes the well-known
-Lamperns, or Nine-eyes, of our rivers (Petromyzon fluviatilis), with
-which most persons are acquainted. They are represented in the sea by
-the frequently larger marine or genuine Lampreys (Petromyzon marinus).
-The nasal tube of these single-nostriled animals does not penetrate the
-palate, and in the auricular organ there are two annular canals.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 4 Main-classes, 9 Classes, and 26 Sub-classes of Vertebrata._
-
-Gen. Morph. vol. ii. Plate VII. pp. 116-160.
-
-
-  ======================================================================================
-              I. =Skull-less= (+Acrania+), or =Tube-hearted= (+Leptocardia+).
-
-      Vertebrata without head, without skull and brain, without centralized heart.
-  --------------------------------------------------------------------------------------
-  1. =Skull-less=          I. Tube-hearted    {  1. Lancelet            1. Amphioxus
-     +Acrania+               _Leptocardia_    {
-  --------------------------------------------------------------------------------------
-
-  II. =Animals with skulls= (+Craniota+) and with =thick-walled hearts= (+Pachycardia+).
-       Vertebrata with head, with skull and brain, with centralized heart.
-
-  ======================================================================================
-     _Main-classes_     |    _Classes_       |      _Sub-classes_    | _Systematic Name_
-    _of the Skulled_    |   _of the_         |     _of the_          |     _of the_
-       _Animals._       | _Skulled Animals._ |   _Skulled Animals._  |  _Sub-classes._
-  --------------------------------------------------------------------------------------
-  2. =Single-Nostriled=  { II. Round mouths   {  2. Hags, or Mucous     2. Hyperotreta
-        +Monorrhina+    {   _Cyclostoma_     {       Fish                 (Myxinoida)
-                         {                    {  3. Lampreys, or        3. Hyperoartia
-                         {                    {       Pride                (Petromyzontia)
-
-
-                         {     III. Fish      {  4. Primaeval fish       4. Selachii
-                         {      _Pisces_      {  5. Ganoid fish         5. Ganoides
-                         {                    {  6. Osseous fish        6. Teleostei
-                         {
-                         {  IV. Mud-fish      {  7. Mud-fish            7. Protopteri
-  3. =Non-amnionate=     {   _Dipneusta_      {
-                         {
-    +Anamnionata+        {                    {  8. Primaeval            8. Simosauria
-                         {  V. Sea-dragons    {       dragons
-                         {    _Halisauri_     {  9. Snake-dragons       9. Plesiosauria
-                         {                    { 10. Fish-dragons       10. Ichthyosauria
-                         {
-                         { VI. Batrachians    { 11. Mailed Batrachians 11. Phractamphibia
-                         {    _Amphibia_      { 12. Naked Batrachians  12. Lissamphibia
-
-
-  4. =Amnion=            {   VII. Reptiles    { 13. Primary reptiles   13. Tocosauria
-    =Animals=            {    _Reptilia_      { 14. Lizards            14. Lacertilia
-  +Amnionata+            {                    { 15. Serpents           15. Ophidia
-                         {                    { 16. Crocodiles         16. Crocodilia
-                         {                    { 17. Tortoises          17. Chelonia
-                         {                    { 18. Flying reptiles    18. Pterosauria
-                         {                    { 19. Dragons            19. Dinosauria
-                         {                    { 20. Beaked reptiles    20. Anomodontia
-                         {
-                         {    VIII. Birds     { 21. Long-tailed        21. Saururae
-                         {       _Aves_       { 22. Fan-tailed         22. Carinatae
-                         {                    { 23. Bush-tailed        23. Ratitae
-                         {
-                         {   IX. Mammals      { 24. Cloacal animals    24. Monotrema
-                         {    _Mammalia_      { 25. Pouched animals    25. Marsupialia
-                         {                    { 26. Placental animals  26. Placentalia
-
-        ----------------------------------------------------------------
-
-                                                       9. Mammals
-                                                         _Mammalia_
-                                       8. Birds              |
-                                         _Aves_              |
-                                            |                |
-                                       7. Reptiles           |
-                                          _Reptilia_         |
-                         5. Sea-dragons     |                |
-                          _Halisauria_      \-------v--------/
-                               |                    |
-  Osseous fish                 |              =Amnion Animals=
-  _Teleostei_    4. Mud-fish   |                +Amniota+
-      |            _Dipneusta_ |                    |
-      |               |        |                    |
-      |               |        |              6. Batrachians
-  Ganoid fish         |        |                 _Amphibia_
-   _Ganoidei_         |        |                    |
-      |               |        |                    |
-      |               \--------------v--------------/
-      |                              |
-      |           Vertebrate animals breathing through lungs
-      |                        _Amphipneumones_
-      |                              |
-      |                              |
-      \------------v-----------------/
-     Primaeval fish      Selachii
-      3. Fishes         _Pisces_
-  =Double-nostriled=   +Amphirrhina+
-                   |                          2. Round-mouthed
-                   |                             _Cyclostoma_
-                   |                                  |
-                   |                                  |
-                   \--------------------v-------------/
-                   =Single-nostriled=       Monorrhina
-                   =Animals with skulls=    +Craniota+
-
-               1. Tube-hearted          |
-                 _Leptocardia_          |
-                       |                |
-                       |                |
-                       \---------v------/
-            _Ascidiae_            |
-  Sea-barrels   |       =Skull-less Animals=
-  _Thaliacea_   |           +Acrania+
-      |         |       =Vertebrate Animals=
-      |         |          +Vertebrata+
-      \----v----/                |
-           |                     |
-  =Tunicate Animals=             |
-       +Tunicata+                |
-           |                     |
-           |                     |
-           \-----------v---------/
-                       |
-                     Worms
-                    _Vermes_
-
-
-All existing Vertebrate animals, with the exception of the Monorrhina
-and Amphioxus just mentioned, belong to the group which we designate as
-Double-nostriled animals (Amphirrhina). All these animals possess (in
-spite of the great variety in the rest of their forms) a nose consisting
-of two lateral halves, a jaw-skeleton, a sympathetic nervous system,
-three annular canals connected with the auricular sac, and a spleen.
-Further, all Double-nostriled animals possess a bladder-shaped expansion
-of the gullet, which, in Fish, has developed into the swimming bladder,
-but in all other Double-nostriled animals into lungs. Finally, in all
-Double-nostriled animals there exist in the youngest stage of growth the
-beginnings of two pairs of extremities, or limbs, a pair of fore legs,
-or breast fins, and a pair of hinder legs, or ventral fins. One of these
-pairs of legs sometimes degenerates (as in the case of eels, whales,
-etc.), or both pairs of legs (as in Caeciliae and serpents) either
-degenerate or entirely disappear; but even in these cases there exists
-some trace of their original beginning in an early embryonic period, or
-the useless remains of them may be found in the form of rudimentary
-organs. (Compare above, vol. i. p. 13.)
-
-From all these important indications we may conclude with full assurance
-that all double-nostriled animals are derived from a single common
-primary form, which developed either directly or indirectly during the
-primordial period out of the Monorrhina. This primary form must have
-possessed the organs above mentioned, and also the beginning of a
-swimming bladder and of two pairs of legs or fins. It is evident, that
-of all still living double-nostriled animals, the lowest forms of sharks
-are most closely allied to this long since extinct, unknown, and
-hypothetical primary form, which we may call the Primary
-Double-nostriled animals (Proselachii). We may therefore look upon the
-group of primaeval fish, or Selachii, to which the _Proselachii_ probably
-belonged, as a primary group, not only of the Fish class, but of the
-whole main-class of double-nostriled animals.
-
-The class of _Fish_ (Pisces) with which we accordingly begin the series
-of Double-nostriled animals, is distinguished from the other six classes
-of the series by the swimming bladder never developing into lungs, but
-acting only as a hydrostatic apparatus. Agreeing with this, we find that
-in fish the nose is formed by two blind holes in front of the mouth,
-which never pierce the palate so as to open into the cavity of the
-mouth. In the other six classes of double-nostriled animals, both
-nostrils are changed into air passages which pierce the palate, and thus
-conduct air to the lungs. Genuine fish (after the exclusion of the
-Dipneusta) are accordingly the only double-nostriled animals which
-exclusively breathe through gills and never through lungs. In accordance
-with this, they all live in water, and both pairs of their legs have
-retained the original form of paddling fins.
-
-
-SYSTEMATIC SURVEY
-
-_Of the 7 Legions and 15 Orders of the Fishes._
-
-
- ---------------------------------------------------------------------------------
-  _Sub-classes_ |      _Legions_     |      _Orders_       |        _Examples_
-      _of_      |        _of_        |        _of_         |          _from_
-    _Fishes._   |      _Fishes._     |      _Fishes._      |       _the Orders._
- ---------------------------------------------------------------------------------
-                 {
-                 {                    {  1. Sharks            Sharks, dog-fish
-                 {   I. Transverse    {    _Squalacei_
-        A.       {       mouths       {  2. Rays              Spiked rays, electric
-    =Primaeval=   {    _Plagiostomi_   {    _Rajacei_           rays, etc.
-      =Fish=     {
-    +Selachii+   {    II. Sea-Cats    {  3. Sea-Cats          Chimaera, Calorrhynchias
-                 {    _Holocephali_   {    _Chimaeracei_
-
-
-                 {                    {  4. Buckler-heads     Cephalaspidae, Placoderma,
-                 { III. Mailed Ganoid {    _Pamphracte_        etc.
-                 {        Fish        {  5. Sturgeons         Spoon-sturgeons, sturgeons,
-                 {     _Tabuliferi_   {    _Sturiones_         sterlet, etc.
-                 {
-                 {                    {  6. _Efulcri_         Double-finned
-         B.      { IV. Angular-scaled {  7. _Fulcrati_        Palaeoniscus, bony pike,
-      =Ganoid=   {     Ganoid Fish    {                        etc.
-       =Fish=    {     _Rhombiferi_   {  8. _Semaeopteri_      African finny pike, etc.
-     +Ganoides+  {
-                 {  V. Round-scaled   {  9. _Coeloscolopes_   Holoptychius, Coelacanthides,
-                 {     Ganoid Fish    {                        etc.
-                 {     _Cycliferi_    { 10. _Pycnoscolopes_   Coccolepida, Amiadae,
-                                                               etc.
-
-                { VI. Osseous Fish   {
-                {    with an air     { 11. Herring species    Herrings, salmon, carp,
-                {   passage to the   {    _Thrissogenes_       etc.
-         C.     {      swimming      { 12. Eel species        Eels, snake eels, electric
-      =Osseous= {       bladder      {    _Enchelygenes_       eels, etc.
-       =Fish=   {     _Physostomi_   {
-    +Teleostei+ {
-                { VII.  Osseous Fish { 13. _Stichobranchii_   Perch, wrasse, turbot,
-                {    without an air  {                         etc.
-                {    passage to the  { 14. _Plectognathi_     Trunk fish, globe fish,
-                {       swimming     {                         etc.
-                {        bladder     { 15. _Lophobranchii_    Pipe fish, sea horses,
-                {     _Physoclisti_  {                         etc.
-
-        ----------------------------------------------------------------
-
-PEDIGREE OF THE NON-AMNIONATE CRANIOTA.
-
-
-  Plectognathi                                              Anura
-       |      Lophobranchia                     Peromela      |
-       |             |                              |         |
-       |             |                              |       Sozura
-       \-------v-----/            Labyrinthodonta   |         |
-               |                           |        |         |
-         Stichobranchia                    |        |         |
-         +Physoclisti+                     \--v-----/         |
-               |                              |               |
-  Enchelygenes |                          Ganocephala    Sozobranchia
-        |      |                        +Phractamphibia+ +Lissamphibia+
-        |      |                              |               |
-        \--v---/                              |               |
-           |                                  \-------v-------/
-           |                                          |
-      Thrissogenes                               +Amphibia+
-      +Physostomi+           Semaeopteri               |
-      +Teleostei+                 |                   |
-           |                      |       Protopteri  |
-           |            Fulcrati  |           |       |            Plesiosauria
-     Pycnoscolopes          |     |           |       | Icthyosauria     |
-           |                |     |           |       |       |          |
-    Coeloscolopes        Efulcri  |           |       |       |          |
-      +Cycliferi+       +Rhombiferi+          |       |       |          |
-    (Cycloganoides)    (Rhomboganoides)       |       |       |          |
-           |                  |               |       |       |          |
-           \---------v--------/               |       |       \----v-----/
-                     |                   +Dipneusta+   |            |
-                Placoderma                    |       |        Simosauria
-   Sturiones         |                        |       |        +Halisauria+
-       |             |                        |       |            |
-  Cephalaspidae       |       Rajacei          \-----------v--------/
-       |             |          |                         |
-       |             |          |                  Amphipneumona
-       \-----v-------/          |                         |
-             |                  |                         |
-         Pamphracti             |                         |
-        +Tabuliferi+            |                         |
-       (Placoganoides)          |   Chimaeracei            |
-         +Ganoides+             |  +Holocephali+          |
-             |                  |       |                 |
-         Squalacei              |       |                 |
-             |                  |       |                 |
-             \--------v---------/       |                 |
-                      |                 |                 |
-                 +Plagiostomi+          |                 |
-                      |                 |                 |
-                      \-------------v---------------------/
-                                    |
-                                +Selachii+
-                                  +Fish+
-                              +Amphirrhina+
-                                    |             Cyclostoma
-                                    |            +Monorrhina+
-                                    |                 |
-                                    \-------v---------/
-                                            |
-                                        +Craniota+
-
-
-Genuine fish are divided into three distinct sub-classes, namely,
-Primaeval fish, Ganoid fish, and Osseous fish. The oldest of these, where
-the original form has been most faithfully preserved, is that of the
-_Primaeval fish_ (Selachii). Of these there still exist Sharks (Squali),
-and Rays (Rajae), which are classed together as cross-mouthed fishes
-(Plagiostomi), and the strange and grotesquely formed Sea-cats, or
-_Chimaeracei_ (Holocephali). These primary fish of the present day, which
-are met with in all seas, are only poor remains of the prevailing animal
-groups, rich in forms, which the Selachii formed in the earlier periods
-of the earth's history, and especially during the palaeolithic period.
-Unfortunately all Primaeval fish possess a cartilaginous, never a
-completely osseous skeleton, which is but little, if at all, capable of
-being petrified. The only hard parts of the body which could be
-preserved in a fossil state, are the teeth and fin-spikes. These are
-found in the older formations in such quantities, varieties, and sizes,
-that we may, with certainty, infer a very considerable development of
-Primaeval fish in those remote ages. They are even found in the Silurian
-strata, which contain but few remains of other Vertebrata, such as
-Enamelled fish (and these only in the most recent part, that is, in the
-upper Silurian). By far the most important and interesting of the three
-orders of Primaeval fish are Sharks; of all still living double-nostriled
-animals, they are probably most closely allied to the original primary
-form of the whole group, namely, to the Proselachii. Out of these
-Proselachii, which probably differed but little from genuine Sharks,
-Enamelled fish, and the present Primaeval fish, in all probability,
-developed in one direction, and the Dipneusta, Sea-dragons, and Amphibia
-in another.
-
-The _Ganoid_, or _Enamelled fish_ (Ganoides), in regard to their anatomy
-stand midway between the Primaeval and the Osseous fish. In many
-characteristics they agree with the former, and in many others with the
-latter. Hence, we infer that genealogically they form the transition
-from Primaeval to Osseous fish. The Ganoids are for the most part
-extinct, and more nearly so than the Primaeval fish, whereas they were
-developed in great force during the entire palaeolithic and mesolithic
-periods. Ganoid fish are divided into three legions according to the
-form of their external covering, namely, Mailed, Angular-scaled, and
-Round-scaled. The _Mailed Ganoid fish_ (Tabuliferi) are the oldest, and
-are directly allied to the Selachii, out of which they originated.
-Fossil remains of them, though rare, are found even in the upper
-Silurian (Pteraspis ludensis of the Ludlow strata). Gigantic species of
-them, coated with strong bony plates, are found in the Devonian system.
-But of this legion there now lives only the small order of Sturgeons
-(Sturiones), including the Spade-sturgeons (Spatularidae), and those
-Sturgeons (Accipenseridae) to which belong, among others, the Huso, which
-yields isinglass, or sturgeon's sound, and the Caviar-sturgeon, whose
-eggs we eat in the shape of caviar, etc. Out of the mailed Ganoid fish,
-the angular and round-scaled ones probably developed as two diverging
-branches. The _Angular-scaled Ganoid fish_ (Rhombiferi)--which can be
-distinguished at first sight from all other fish by their square or
-rhombic scales--are at present represented only by a few survivors,
-namely, the Finny Pike (Polypterus) in African rivers (especially the
-Nile), and by the Bony Pike (Lepidosteus) in American rivers. Yet during
-the palaeolithic and the first half of the mesolithic epochs this legion
-formed the most numerous group of fishes. The third legion, that of
-_Round-scaled Ganoid fish_ (Cycliferi), was no less rich in forms, and
-lived principally during the Devonian and Coal periods. This legion, of
-which the Bald Pike (Amia), in North American rivers, is the only
-survivor, was especially important, inasmuch as the third sub-class of
-fish, namely, Osseous fish, developed out of it.
-
-_Osseous fish_ (Teleostei) include the greater portion of the fish of
-the present day. Among these are by far the greater portion of marine
-fish, and all of our fresh-water fish except the Ganoid fish just
-mentioned. This class is distinctly proved by numerous fossils to have
-arisen about the middle of the Mesolithic epoch out of Ganoid fish, and
-moreover out of the Round-scaled, or Cycliferi. The Thrissopidae of the
-Oolitic period (Thrissops, Leptolepis, Tharsis), which are most closely
-allied to the herrings of the present day, are probably the oldest of
-all Osseous fish, and have directly arisen out of Round-scaled Ganoid
-fish, closely allied to the existing Amia. In the older Osseous fish of
-the legion called _Physostomi_, as also in the Ganoides, the swimming
-bladder throughout life was connected with the throat by a permanent air
-passage (a kind of windpipe). This is still the case with all the fish
-belonging to this legion, namely, with herrings, salmon, carp, shad,
-eels, etc. However, during the chalk period this air passage, in some of
-the Physostomi, became constricted and closed, and the swimming bladder
-was thus completely separated from the throat. Hence there arose a
-second legion of Osseous fish, the _Physoclisti_, which did not attain
-their actual development until the tertiary epoch, and soon far
-surpassed the Physostomi in variety. To this legion belong most of the
-sea fish of the present day, especially the large families of the
-Turbot, Tunny, Wrasse, Crowfish, etc., further, the Lock-jaws
-(Plectognathi), Trunk fish, and Globe-fish and the Bushy-gills
-(Lophobranchi), viz., Pipe-fish, and Sea-horses. There are, however,
-only very few Physoclisti among our river fish, for instance, Perch and
-Sticklebacks; the majority of river fish are Physostomi.
-
-Midway between genuine Fish and Amphibia is the remarkable class of
-_Mud-fish_, or _Scaly Sirens_ (Dipneusta, or Protopteri). There now
-exist only a few representatives of this class, namely, the American
-Mud-fish (Lepidosiren paradoxa) in the region of the river Amazon, and
-the African Mud-fish (Protopterus annectens) in different parts of
-Africa. A third large Salamander-fish (Ceratodus Fosteri) has lately
-been discovered in Australia. During the dry season, that is in summer,
-these strange animals bury themselves in a nest of leaves in the dry
-mud, and then breathe air through lungs like the Amphibia. But during
-the wet season, in winter, they live in rivers and bogs, and breathe
-water through gills like fish. Externally, they resemble fish of the eel
-kind, and are like them covered with scales; in many other
-characteristics also--in their internal structure, their skeleton,
-extremities, etc.--they resemble Fish more than Amphibia. But in certain
-features they resemble the Amphibia, especially in the formation of
-their lungs, nose, and heart. There is consequently an endless dispute
-among zoologists, as to whether the Mud-fish are genuine Fish or
-Amphibia. Distinguished zoologists have expressed themselves in favour
-of both opinions. But in fact, owing to the complete blending of
-characteristics which they present, they belong neither to the one nor
-to the other class, and are probably most correctly dealt with as a
-special class of Vertebrata, forming the transition between Fishes and
-Amphibians. The still living Dipneusta are probably the last surviving
-remains of a group which was formerly rich in forms, but has left no
-fossil traces on account of the want of a solid skeleton. In this
-respect, these animals are exactly like the Monorrhina and the
-Leptocardia. However, teeth are found in the Trias which resemble those
-of the living Ceratodus. Possibly the extinct Dipneusta of the
-palaeolithic period, which developed in the Devonian epoch out of
-primaeval fish, must be looked upon as the primary forms of the Amphibia,
-and thus also of all higher Vertebrata. At all events the unknown forms
-of transition--from Primaeval fish to Amphibia--were probably very like
-the Dipneusta.
-
-A very peculiar class of Vertebrate animals, long since extinct, and
-which appears to have lived only during the secondary epoch, is formed
-by the remarkable _Sea-dragons_ (Halisauria, or Enaliosauria, also
-called Nexipoda, or Swimming-footed animals). These formidable animals
-of prey inhabited the mesolithic oceans in great numbers, and were of
-most peculiar forms, sometimes from thirty to forty feet in length. From
-many and excellently preserved fossil remains and impressions, both of
-the entire body of Sea-dragons as well as of single parts, we have
-become very accurately acquainted with the structure of their bodies.
-They are usually classed among Reptiles, whilst some anatomists have
-placed them in a much lower rank, as directly allied to Fish.
-Gegenbaur's recently published investigations, which place the structure
-of their limbs in a true light, have led to the surprising conclusion
-that the Sea-dragons form quite an isolated group, differing widely both
-from Reptiles and Amphibia as well as from Fish. The skeleton of their
-four legs, which are transformed into short, broad, paddling fins (like
-those of fish and whales) furnishes us with a clear proof that the
-Halisauria branched off from the main-stock of Vertebrata at an earlier
-period than the Amphibia. For Amphibia, as well as the three higher
-classes of Vertebrata, are all derived from a common primary form, which
-possessed only _five_ toes or fingers on each leg. But the Sea-dragons
-have (either distinctly developed or in a rudimentary condition as parts
-of the skeleton of the foot) more than five fingers, as have also the
-Selachians or Primaeval fish. On the other hand, they breathed air
-through lungs, like the Dipneusta, although they always swam about in
-the sea. They, therefore, perhaps, in conjunction with the Dipneusta,
-branched off from the Selachii, but did not develop into higher
-Vertebrata; they form an extinct lateral line of the pedigree, which has
-died out.
-
-The more accurately known Sea-dragons are classed into three orders,
-distinct enough one from the other, namely, _Primaeval Dragons_, _Fish
-Dragons_, and _Serpent Dragons_. The _Primaeval Dragons_ (Simosauria) are
-the oldest Sea-dragons, and lived only during the Trias period. The
-skeletons of many different genera of them are met with in the German
-limestone known as "Muschel-kalk." They seem upon the whole to have been
-very like the Plesiosauria, and are, consequently, sometimes united with
-them into one order as Sauropterygia. The _Serpent Dragons_
-(Plesiosauria) lived in the oolitic and chalk periods together with the
-Ichthyosauria. They were characterised by an uncommonly long thin neck,
-which was frequently longer than the whole body, and carried a small
-head with a short snout. When their arched neck was raised they must
-have looked very like a swan; but in place of wings and legs they had
-two pairs of short, flat, oval-paddling fins.
-
-The body of the _Fish Dragons_ (Ichthyosauria) was of an entirely
-different form; these animals may be opposed to the two preceding orders
-under the name of Fish-finners (Ichthyopterygia). They possessed a very
-long extended body, like a fish, and a heavy head with an elongated,
-flat snout, but a very short neck. Externally, they were probably very
-like porpoises. Their tail was very long, whereas it was very short in
-the members of the preceding orders. Also both pairs of paddling fins
-are broader and show very different structure from that seen in the
-other two orders. Probably the Fish Dragons and Serpent Dragons
-developed as two diverging branches out of the Primaeval Dragons; but it
-is also possible that the Plesiosauria alone originated out of the
-Simosauria, and that the Ichthyosauria were lower off-shoots from the
-common stock. At all events, they must all be directly, or indirectly
-derived from the Selachii, or Primaeval fish.
-
-The succeeding classes of Vertebrata, the _Amphibia_ and the _Amniota_
-(Reptiles, Birds, and Mammals), owing to the characteristic structure
-which they all exhibit of five toes to each foot, may all be derived
-from a common primary form, which originated from the Selachii, and
-which possessed five toes on each of its four limbs. When we find a less
-number of toes than five, we can show that the missing ones must have
-been lost in the course of time by adaptation. The oldest known
-Vertebrata with five toes are the _Batrachias_ (Amphibia). We divide
-this class into two sub-classes, namely, mailed Batrachians and naked
-Batrachians, the first of which is distinguished by the body being
-covered with bony plates or scales.
-
-The first and elder sub-class of Amphibia consists of the _Mailed
-Batrachians_ (Phractamphibia), the oldest land living Vertebrata of
-which fossil remains exist. Well-preserved fossil remains of them occur
-in the coal, especially of those with _Enamelled heads_ (Ganocephala),
-which are most closely allied to fish, namely, the Archegosaurus of
-Saarbruck, and the Dendrerpeton of North America. There then follow at a
-later period the gigantic _Labyrinth-toothed animals_ (Labyrinthodonta),
-which are represented in the Permian system by Zygosaurus, but at a
-later period, more especially in the Trias, by Mastodonsaurus,
-Trematosaurus, Capitosaurus, etc. The shape of these formidable
-rapacious animals seems to have been between that of crocodiles,
-salamanders, and frogs, but in their internal structure they were more
-closely related to the two latter, while by their solid coat of mail,
-formed of strong bony plates, they resembled the first animals. These
-gigantic mailed Batrachians seem to have become extinct towards the end
-of the Triassic period. No fossil remains of mailed Batrachia are known
-during the whole of the subsequent periods. However, the still living
-blind Snakes, or _Caeciliae_ (Peromela)--small-scaled Phractamphibia of
-the form and the same mode of life as the earth-worm--prove that this
-sub-class continued to exist, and never became completely extinct.
-
-The second sub-class of Amphibia, the _naked Batrachia_ (Lissamphibia),
-probably originated even during the primary and secondary epochs,
-although fossil remains of them are first found in the tertiary epoch.
-They are distinguished from mailed Batrachia by possessing a naked
-smooth, and slimy skin, entirely without scales or coat of mail. They
-probably developed either out of a branch of the Phractamphibia, or out
-of the same common root with them. The ontogeny of the three still
-living orders of naked Batrachia--the gilled Batrachia, tailed
-Batrachia, and frog Batrachia--distinctly repeats the historical course
-of development of the whole sub-class. The oldest forms are the gilled
-Batrachia (Sozobranchia), which retain throughout life the original
-primary form of naked Batrachia, and possess a long tail, together with
-water-breathing gills. They are most closely allied to the Dipneusta,
-from which, however, they differ externally by the absence of the coat
-of scales. Most gilled Batrachia live in North America: among others of
-the class is the Axolotl, or Siredon, already mentioned. (Compare above,
-vol. i. p. 241.) In Europe the order is only represented by one form,
-the celebrated "Olm" (Proteus anguinus), which inhabits the grotto of
-Adelsberg and other caves in Carinthia, and which, from living in the
-dark, has acquired rudimentary eyes which can no longer see (vol. i. p.
-13). The order of Tailed Batrachia (Sozura) have developed out of the
-gilled Batrachia by the loss of external gills; the order includes our
-black and yellow spotted land Salamander (Salamandra maculata), and our
-nimble aquatic Salamanders (Tritons). Many of them--for instance, the
-celebrated giant Salamanders in Japan (Cryptobranchus Japonicus)--still
-retain the gill-slits, although the gills themselves have disappeared.
-All of them, however, retain the tail throughout life. Tritons
-occasionally--when forced to remain in water always--retain their gills,
-and thus remain at the same stage of development as gilled Batrachia.
-(Compare above, vol. i. p. 241.) The third order, the _tailless_ or
-_frog-like Batrachia_ (Anura), during their metamorphosis, not only lose
-their gills, with which in early life (as so-called tadpoles) they
-breathe in water, but also the tail with which they swim about. During
-their ontogeny, therefore, they pass through the course of development
-of the whole sub-class, they being at first _Gilled Batrachia_, then
-_Tailed Batrachia_, and finally _Frog-like Batrachia_. The inference
-from this is evidently, that _Frog-like Batrachia_ developed at a later
-period out of _Tailed Batrachia_, as the latter had developed out of
-_Gilled Batrachia_ which originally existed alone.
-
-In passing from the Amphibia to the next class of Vertebrata, namely,
-Reptiles, we observe a very considerable advance in the progress of
-organization. All the double-nostriled animals (Amphirrhina) up to this
-time considered, and more especially the two larger classes of Fish and
-Batrachia, agree in a number of important characteristics, which
-essentially distinguish them from the three remaining classes of
-Vertebrata--Reptiles, Birds, and Mammals. During the embryological
-development of these latter, a peculiarly delicate covering, the _first
-foetal membrane_, or _amnion_, which commences at the navel, is formed
-round the embryo; this membrane is filled with the amnion-water, and
-encloses the embryo or germ in the form of a bladder. On account of this
-very important and characteristic formation, we may comprise the three
-most highly developed classes of Vertebrata under the term
-_Amnion-animals_ (Amniota). The four classes of double-nostriled animals
-which we have just considered, in which the amnion is wanting (as is the
-case in all lower Vertebrate animals, single-nostriled and skull-less
-animals), may on the other hand be opposed to the others as _amnion-less
-animals_ (Anamnia).
-
-The formation of the foetal membrane, or amnion, which distinguishes
-reptiles, birds, and mammals from all other Vertebrata, is evidently a
-very important process in their ontogeny, and in the phylogeny which
-corresponds with it. It coincides with a series of other processes,
-which essentially determine the higher development of Amnionate animals.
-The first of these important processes is the _total loss of gills_, for
-which reason the Amniota, under the name of _Gill-less animals_
-(Ebranchiata), were formerly opposed to all other Vertebrate animals
-which breathed through gills (Branchiata). In all the Vertebrate already
-discussed, we found that they either always breathed through gills, or
-at least did so in early life, as in the case of Frogs and Salamanders.
-On the other hand, we never meet with a Reptile, Bird, or Mammal which
-at any period of its existence breathes through gills, and the
-gill-arches and openings which do exist in the embryos, are, during the
-course of the ontogeny, changed into entirely different structures,
-viz., into parts of the jaw-apparatus and the organ of hearing. (Compare
-above, vol. i. p. 307.) All Amnionate animals have a so-called cochlea
-in the organ of hearing, and a "round window" corresponding with it.
-These parts are wanting in the Amnion-less animals; moreover, their
-skull lies in a straight line with the axis of the vertebral column. In
-Amniotic animals the base of the skull appears bent in on the abdominal
-side, so that the head sinks upon the breast. (Plate III. Fig. _C_, _D_,
-_G_, _H_.) The organs of tears at the side of the eye also first develop
-in the Amniota.
-
-The question now is, When did this important advance take place in the
-course of the organic history of the earth? When did the common ancestor
-of all Amniota develop out of a branch of the Non-amniota, to wit, out
-of the branch of the Amphibia?
-
-To this question, the fossil remains of Vertebrata do not give us a very
-definite, but still they do give an approximate, answer. For with the
-exception of two lizard-like animals found in the Permian system (the
-Proterosaurus and Rhopalodon), all the fossil remains of Amniota, as yet
-known, belong to the _secondary_, _tertiary_, and _quaternary epochs_.
-With regard to the two Vertebrata just named, it is still doubtful
-whether they are genuine reptiles, or perhaps Amphibia of the salamander
-kind. Their skeleton alone is known to us, and even this not perfectly.
-Now as we know nothing of the characteristic features of their soft
-parts, it is quite possible that the Proterosaurus and Rhopalodon were
-non-amnionate animals more closely allied to Amphibia than to Reptiles;
-possibly they belonged to the transition form between the two classes.
-But, on the other hand, as undoubted fossil remains of Amniota have been
-found as early as the Trias, it is probable that the _main class of
-Amniota_ first developed in the Trias, that is, in the beginning of the
-Mesolithic epoch. As we have already seen, this very period is evidently
-one of the most important turning points in the organic history of the
-earth. The palaeolithic fern forests were then replaced by the pine
-forests of the Trias period; important transformations then took place
-in many of the classes of Invertebrata. Articulated marine lilies
-(Colocrina) developed out of the plated ones (Phatnocrina.) The
-Autechinidae, or sea-urchins with only twenty rows of plates, took the
-place of the palaeolithic Palechinidae, the sea-urchins with more than
-twenty rows of plates. The Cystideae, Blastoideae, Trilobita, and other
-characteristic groups of Invertebrata of the primary period became
-extinct. It is no wonder that transforming conditions of adaptation
-powerfully influenced the Vertebrate tribes also in the beginning of the
-Trias period, and caused the origin of Amniotic animals.
-
-If, however, the two Lizard and Salamander-like animals of the Permian
-system, the Proterosaurus and Rhopalodon, are considered genuine
-Reptiles, and consequently the most ancient Amniota, then the origin of
-this main class must necessarily have taken place in the preceding
-period, towards the end of the primary, namely, in the Permian period.
-However, all other remains of Reptiles, which were formerly believed to
-have been found in the Permian and the Coal system, or even in the
-Devonian system, have been proved to be either not remains of Reptiles
-at all, or to belong to a more recent date (for the most part to the
-Trias). (Compare Plate XIV.)
-
-The common hypothetical primary form of all Amniotic animals, which we
-may call _Protamnion_, and which was possibly nearly related to the
-Proterosaurus, very probably stood upon the whole midway between
-salamanders and lizards, in regard to its bodily formation. Its
-descendants divided at an early period into two different lines, one of
-which became the common primary form of Reptiles and Birds, the other
-the primary form of Mammals.
-
-Of all the three classes of Amniota, _Reptiles_ (Reptilia, or Pholidota,
-also called Sauria in the widest sense), remain at the lowest stage of
-development, and differ least from their ancestors, the Amphibia. Hence
-they were formerly universally included among them, although their whole
-organization is much more like that of Birds than Amphibia. There now
-exist only four orders of Reptiles, namely,--Lizards, Serpents,
-Crocodiles, and Tortoises. They, however, form but a poor remnant of the
-exceedingly various and highly developed host of Reptiles which lived
-during the Mesolithic, or Secondary epoch, and predominated over all
-other Vertebrata. The immense development of Reptiles during the
-Secondary epoch is so characteristic that we could as well name it after
-those animals as after the Gymnosperms (p. 111). Twelve of the
-twenty-seven sub-orders, given on the accompanying table, and four of
-the eight orders, belong exclusively to the secondary period. These
-mesolithic groups are marked by an asterisk. All the orders, with the
-exception of Serpents, are found fossilized even in the Jura and Trias
-periods.
-
-[Illustration: _Pl. XIV._
-
-  [Horizontal axis:]
-  Branches,
-  Classes,
-  and Sub-Classes,
-  of the Vertebrate
-  Stem.
-
-  Prochordata
-  Evertebrate
-  Forefathers
-  of the
-  Vertebrate
-
-  Skull-less
-  (Acrania)
-  or
-  Tube-hearted
-  Fish,
-  (Leptocardia)
-
-  Single
-  nostrilled
-  (Monorrhina)
-  or
-  Round-mouthed
-  Fishes
-  (Cyclostoma)
-
-  Anamnia { Paired-nostrilled forms or Amphirrhina
-          { with gills, without Amnion.
-    Fish, Pisces
-
-      Primeval
-      Fish,
-      Selachii.
-
-      Enamelled
-      Fish,
-      Ganoides.
-
-      Bony
-      Fish,
-      Teleostei.
-
-    Mud
-    Fish,
-    Dipneusta.
-
-    Sea-Dragons,
-    Halisauria.
-
-    Frogs and
-    Newts,
-    Amphibia.
-
-  Amniota { Paired nostrilled or Amphirrhina
-          { with Amnion, without gills.
-
-    Reptiles, Reptilia.
-
-      Primaeval
-      Reptiles,
-      Tocosauria.
-
-      Lizards,
-      Lacertilia.
-
-      Snakes,
-      Ophidia.
-
-      Crocodiles,
-      Crocodilia.
-
-      Tortoises,
-      Chelonia.
-
-      Flying
-      Reptiles,
-      Pterosauria.
-
-      Dragons,
-      Dinosauria.
-
-      Billed
-      Reptiles,
-      Anomodontia.
-
-    Birds,
-    Aves.
-
-    Suckling animals, Mammalia.
-
-      Billed
-      Animals,
-      Monotrema.
-
-      Pouched
-      Animals,
-      Marsupialia.
-
-      Placental
-      Animals,
-      Placentalia.
-
-  [Vertical axis:]
-  Cenolithic or
-  Tertiary Epoch.
-
-    Pliocene
-    Age.
-
-    Miocene
-    Age.
-
-    Eocene
-    Age.
-
-  Mesolithic or
-  Secondary Epoch.
-
-    Chalk
-    Period.
-
-    Jurassic
-    Period.
-
-    Triassic
-    Period.
-
-  Palaeolithic or
-  Primary Epoch.
-
-    Permian
-    Period.
-
-    Coal
-    Period.
-
-    Devonian
-    Period.
-
-  Archilithic or
-  Primordial Epoch.
-
-    Silurian
-    Period.
-
-    Cambrian
-    Period.
-
-    Laurentian
-    Period.
-
-  [Legend:]
-  Single or
-  MONOPHYLETIC PEDIGREE
-  of the Stem of the
-  BACK-BONED ANIMALS
-  Based on Palaeontology.
-
-  Relative lengths of the 5
-  Epochs in per centages.
-
-  Quarternary Epoch      0.5
-  Tertiary Epoch         2.3
-  Secondary Epoch       11.5
-  Primary Epoch         32.1
-  Primordial Epoch      53.6
-                      ------
-              _Total_  100.0]
-
-In the first order, that of _Primary Reptiles_, or _Primary Creepers_
-(Tocosauria), we class the extinct _Thecodontia_ of the Trias, together
-with those Reptiles which we may look upon as the common primary form of
-the whole class. To the latter, which we may call _Primaeval Reptiles_
-(Proreptilia), the Proterosaurus of the Permian system very probably
-belongs. The seven remaining orders must be considered as diverging
-branches, which have developed in different directions out of that
-common primary form. The Thecodontia of the Trias, the only positively
-known fossil forms of Tocosauria, were Lizards which seem to have been
-like the still living monitor lizards (Monitor, Varanus).
-
-
-SYSTEMATIC SURVEY
-
-_Of the 8 Orders and 27 Sub-orders of Reptiles._
-
-(Those groups marked with * became extinct even during the Secondary
-Period.)
-
-  -----------------------------------------------------------------------------------
-                     |     _Sub-orders_       | _Systematic Name_  |  _A Generic Name_
-      _Orders_       |         _of_           |     _of the_       |        _as_
-   _of Reptiles._    |      _Reptiles._       |   _Sub-orders._    |    _an example._
-  -----------------------------------------------------------------------------------
-  I. =Primary=       {  1. Primaeval reptiles  1. Proreptilia       * (Proterosaurus?)
-     =Reptiles=      {
-   +Tocosauria+      {  2.                    2. Thecodontia       * Palaeosaurus
-
-                     {  3. Cleft-tongued      3. Fissilingues        Monitor
-                     {  4. Thick-tongued      4. Crassilingues       Iguana
-  II. =Lizards=      {  5. Short-tongued      5. Brevilingues        Anguis
-   +Lacertilia+      {  6. Ringed lizards     6. Glyptodermata       Amphisbaena
-                     {  7. Chameleons         7. Vermilingues        Chamaeleo
-
-                     {  8. Adders             8. Aglyphodonta        Coluber
-                     {  9. Tree serpents      9. Opisthoglypha       Dipsas
-  III. =Serpents=    { 10.                   10. Proteroglypha       Hydrophis
-       +Ophidia+     { 11. Vipers            11. Solenoglypha        Vipera
-                     { 12. Worm serpents     12. Opoterodonta        Typhlops
-
-                     { 13. Amphicoela        13. Teleosauria       * Teleosaurus
-  IV. =Crocodiles=   { 14. Opisthocoela      14. Steneosauria      * Steneosaurus
-   +Crocodilia+      { 15. Prosthocoela      15. Alligatores         Alligator
-
-                     { 16. Sea tortoises     16. Thalassita          Chelone
-   V. =Tortoises=    { 17. River tortoises   17. Potamita            Trionyx
-   +Chelonia+        { 18. Marsh tortoises   18. Elodita             Emys
-                     { 19. Land tortoises    19. Chersita            Testudo
-
-                     { 20. Long-tailed       20. Rhamphorhynchi    * Rhamphorhynchus
-   VI. =Flying=      {    Flying lizards
-    =Reptiles=       { 21. Short-tailed      21. Pterodactyli      * Pterodactylus
-  +Pterosauria+*     {    Flying lizards
-
-                     { 22. Giant dragons     22. Harpagosauria     * Megalosaurus
-  VII. =Dragons=     { 23. Elephantine       23. Therosauria       * Iguanodon
-  +Dinosauria+*      {      dragons
-
-                     { 24. Dog-toothed       24. Cynodontia        * Dicynodon
-  VIII. =Beaked=     { 25. Toothless         25. Cryptodontia      * Udenodon
-  =Reptiles=         { 26. Kangaroo reptiles 26. Hypsosauria       * Compsognathus
-  +Anomodontia+*     {
-                     { 27. Bird reptiles     27. Tocornithes       * (Tocornis)
-
-
-Of the four orders of reptiles now existing, and which, moreover, have
-alone represented the class since the beginning of the tertiary epoch,
-that of _Lizards_ (Lacertilia) is probably most closely allied to the
-extinct Primary Reptiles, and especially through the monitors already
-named. The class of _Serpents_ (Ophidia) developed out of a branch of
-the order of lizards, and this probably not until the beginning of the
-tertiary epoch. At least we at present only know of fossil remains of
-serpents from the tertiary strata. _Crocodiles_ (Crocodilia) existed
-much earlier; the Teleosauria and Steneosauria belonging to the class
-are found fossil in large quantities even in the Jura; but the still
-living alligators are first met with in a fossil state in the chalk and
-tertiary strata. The most isolated of the four existing orders of
-reptiles consists of the remarkable group of _Tortoises_ (Chelonia);
-fossils of these strange animals are first met with in the Jura. In some
-characteristics they are allied to Amphibia, in others, to Crocodiles,
-and by certain peculiarities even to Birds, so that their true position
-in the pedigree of Reptiles is probably far down at the root. The
-extraordinary resemblance of their embryos to Birds, manifested even at
-later stages of the ontogenesis, is exceedingly striking.
-
-The four extinct orders of Reptiles show among one another, and, with
-the four existing orders just mentioned, such various and complicated
-relationships, that in the present state of our knowledge we are obliged
-to give up the attempt at establishing their pedigree. The most
-deviating and most curious forms are the _Flying Reptiles_
-(Pterosauria); flying lizards, in which the extremely elongated fifth
-finger of the hand served to support an enormous flying membrane. They
-probably flew about, in the secondary period, much in the same way as
-the bats of the present day. The smallest flying lizards were about the
-size of a sparrow; the largest, however, with a breadth of wing of more
-than sixteen feet, exceeded the largest of our living flying birds in
-stretch of wing (condor and albatross). Numerous fossil remains of them,
-of the long-tailed Rhamphorhynchia and of the short-tailed Pterodactylae
-are found in all the strata of the Jura and Chalk periods, but in these
-only.
-
-Not less remarkable and characteristic of the Mesolithic epoch was the
-group of _Dragons_ (Dinosauria, or Pachypoda). These colossal reptiles,
-which attained a length of more than fifty feet, are the largest
-inhabitants of the land which have ever existed on our globe; they lived
-exclusively in the secondary epoch. Most of their remains are found in
-the lower cretaceous system, more especially in the Wealden formations
-of England. The majority of them were fearful beasts of prey (the
-Megalosaurus from twenty to thirty, the Pelorosaurus from forty to fifty
-feet in length). The Iguanodon, however, and some others lived on
-vegetable food, and probably played a part in the forests of the chalk
-period similar to that of the unwieldy but smaller elephants,
-hippopotami, and rhinoceroses of the present day.
-
-The _Beaked Reptiles_ (Anomodontia), likewise also long since extinct,
-but of which very many remarkable remains are found in the Trias and
-Jura, were perhaps closely related to the Dragons. Their jaws, like
-those of most Flying Reptiles and Tortoises, had become changed into a
-beak, which either possessed only degenerated rudimentary teeth, or no
-teeth at all. In this order, if not in the preceding one, we must look
-for the primary parents of the bird class, which we may call Bird
-Reptiles (Tocornithes). Probably very closely related to them was the
-curious, kangaroo-like Compsognathus from the Jura, which in very
-important characteristics already shows an approximation to the
-structure of birds.
-
-The class of _Birds_ (Aves), as already remarked, is so closely allied
-to Reptiles in internal structure and by embryonal development, that
-they undoubtedly originated out of a branch of this class. Even a glance
-at Plates II. and III. will show that the embryos of birds at a time
-when they already essentially differ from the embryos of Mammals, are
-still scarcely distinguishable from those of Tortoises and other
-Reptiles. The cleavage of the yolk is partial in the case of Birds and
-Reptiles, in Mammals it is total. The red blood-cells of the former
-possess a kernel, those of the latter do not. The hair of Mammals
-develops in closed follicles in the skin, but the feathers of birds and
-also the scales of reptiles develop in hillocks on the skin. The lower
-jaw of the latter is much more complicated than that of Mammals; the
-latter do not possess the quadrate bone of the former. Whereas in
-Mammals (as in the case of Amphibia) the connection between the skull
-and the first neck vertebra is formed by two knobbed joints, or
-condyles, in Birds and Reptiles those have become united into a single
-condyle. The two last classes may therefore justly be united into one
-group as Monocondylia, and contrasted to Mammals, or Dicondylia.
-
-The deviation of Birds from Reptiles, in any case, first took place in
-the mesolithic epoch, and this moreover probably during the Trias. The
-oldest fossil remains of birds are found in the upper Jura
-(Archaeopteryx). But there existed, even in the Trias period, different
-Saurians (Anomodonta) which in many respects seem to form the transition
-from the Tocosauria to the primary ancestors of Birds, the hypothetical
-Tocornithes. Probably these Tocornithes were scarcely distinguishable
-from other beaked lizards in the system, and were closely related to the
-kangaroo-like Compsognathus from the Jura of Solenhofen. Huxley classes
-the latter with the Dinosauria, and believes them to be the nearest
-relations to the Tocornithes.
-
-The great majority of Birds--in spite of all the variety in the
-colouring of their beautiful feathery dress, and in the formation of
-their beaks and feet--are of an exceedingly uniform organization, in
-much the same way as are the class of insects. The bird form has adapted
-itself on all sides to the external conditions of existence, without
-having thereby in any way essentially deviated from the strict
-hereditary type of its characteristic structure. There are only two
-small groups, the feather-tailed birds (Saururae) and those of the
-ostrich kind, which differ considerably from the usual type of bird,
-namely, from those with keel-shaped breasts (Carinatae), and hence the
-whole class may be divided into three sub-classes.
-
-The first sub-class, the _Reptile-tailed_, or _Feather-tailed Birds_
-(Saururae), are as yet known only through a single, and that an
-imperfect, fossil impression, which, however, in being the oldest and
-also a very peculiar fossil bird, is of great importance. This fossil is
-the Primaeval Griffin, or Archaeopteryx lithographica, of which as yet
-only one specimen has been found in the lithographic slate at
-Solenhofen, in the Upper Jura system of Bavaria. This remarkable bird
-seems on the whole to have been of the size and form of a large raven,
-especially as regards the legs, which are in a good state of
-preservation; head and breast unfortunately are wanting. The formation
-of the wings deviates somewhat from that of other birds, but that of the
-tail still more so. In all other birds the tail is very short and
-composed of but few short vertebrae; the last of these have grown
-together into a thin, bony plate standing perpendicularly, upon which
-the rudder-feathers of the tail are attached in the form of a fan. The
-Archaeopteryx, however, has a long tail like a lizard, composed of
-numerous (20) long thin vertebrae, and on every vertebra are attached
-the strong rudder-feathers in twos, so that the whole tail appears
-regularly feathered. This same formation of the tail part of the
-vertebral column occurs transiently in the embryos of other birds, so
-that the tail of the Archaeopteryx evidently represents the original form
-of bird-tail inherited from reptiles. Large numbers of similar birds
-with lizard-tails probably lived during the middle of the secondary
-period; accident has as yet, however, only revealed this one fossil.
-
-The _Fan-tailed_, or _Keel-breasted birds_ (Carinatae), which form the
-second sub-class, comprise all living Birds of the present day, with the
-exception of those of the ostrich kind, or Ratitae. They probably
-developed out of Feather-tailed Birds during the first half of the
-secondary period, namely, in the Jura or Chalk period, by the hinder
-tail vertebrae growing together, and by the tail becoming shortened. Only
-very few remains of them are known from the secondary period, and these
-moreover only out of the last section of it, namely, from the Chalk.
-These remains belong to a swimming bird of the albatross species, and a
-wading bird like a snipe. All the other fossil remains of birds as yet
-known have been found in the tertiary strata.
-
-The _Bushy-tailed_, or _Ostrich-like Birds_ (Ratitae), also called
-_Running Birds_ (Cursores), the third and last sub-class, is now
-represented only by a few living species, by the African ostrich with
-two toes, the American and Australian ostrich with three toes, by the
-Indian cassowary and the four-toed kiwi, or Apteryx, in New Zealand. The
-extinct giant birds of Madagascar (AEpyornis) and the New Zealand
-Dinornis, which were much larger than the still living ostriches, also
-belong to this group. The Birds of the ostrich kind--by giving up the
-habit of flying, by the degeneration of the muscles for flying resulting
-from this, and of the breast bone which serves as their support, and by
-the corresponding stronger development of the hinder legs for
-running--have probably arisen out of a branch of the Keel-breasted
-birds. But possibly, as Huxley thinks, they may be the nearest relations
-of the Dinosauria and of the Reptiles akin to them, especially of the
-Compsognathus; at all events, the common primary form of all Birds must
-be looked for among the extinct Reptiles.
-
-
-
-
-CHAPTER XXI.
-
-PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM.
-
-IV. MAMMALS.
-
-
-  The System of Mammals according to Linnaeus and
-  Blainville.--Three Sub-classes of Mammals (Ornithodelphia,
-  Didelphia, Monodelphia).--Ornithodelphia, or Monotrema.--Beaked
-  Animals (Ornithostoma).--Didelphia, or Marsupials.--Herbivorous
-  and Carnivorous Marsupials.--Monodelphia, or Placentalia
-  (Placental Animals).--Meaning of the Placenta.--Tuft
-  Placentalia.--Girdle Placentalia.--Disc
-  Placentalia.--Non-deciduates, or Indeciduata.--Hoofed
-  Animals.--Single and Double-hoofed Animals.--Whales.--Toothless
-  Animals.--Deciduates, or Animals with
-  Decidua.--Semi-apes.--Gnawing Animals.--Pseudo-hoofed
-  Animals.--Insectivora.--Beasts of Prey.--Bats.--Apes.
-
-
-There are only a few points in the classification of organisms upon
-which naturalists have always agreed. One of these few undisputed points
-is the privileged position of the class of Mammals at the head of the
-animal kingdom. The reason of this privilege consists partly in the
-special interest, also in the various uses and the many pleasures, which
-Mammals, more than all other animals, offer to man, and partly in the
-circumstance that man himself is a member of this class. For however
-differently in other respects man's position in nature and in the system
-of animals may have been regarded, yet no naturalist has ever doubted
-that man, at least from a purely morphological point of view, belongs
-to the class of Mammals. From this there directly follows the
-exceedingly important inference that man, by consanguinity also, is a
-member of this class of animals, and has historically developed out of
-long since extinct forms of Mammals. This circumstance alone justifies
-us here in turning our especial attention to the history and the
-pedigree of Mammals. Let us, therefore, for this purpose first examine
-the groups of this class of animals.
-
-Older naturalists, especially considering the formation of the jaw and
-feet, divided the class of Mammals into a series of from eight to
-sixteen orders. The lowest stage of the series was occupied by the
-whales, which seemed to differ most from man, who stands at the highest
-stage, by their fish-like form of body. Thus Linnaeus distinguished the
-following eight orders: (1) Cetae (whales); (2) Belluae (hippopotami and
-horses); (3) Pecora (ruminating animals); (4) Glires (gnawing animals
-and rhinoceroses); (5) Bestiae (insectivora, marsupials, and various
-others); (6) Ferae (beasts of prey); (7) Bruta (toothless animals and
-elephants); (8) Primates (bats, semi-apes, apes, and men). Cuvier's
-classification, which became the standard of most subsequent zoologists,
-did not rise much above that of Linnaeus. Cuvier distinguished the
-following eight orders: (1) Cetacea (whales); (2) Ruminantia (ruminating
-animals); (3) Pachyderma (hoofed animals, with the exclusion of
-ruminating animals); (4) Edentata (animals poor in teeth); (5) Rodentia
-(gnawing animals); (6) Carnassia (marsupials, beasts of prey,
-insectivora, and bats); (7) Quadrumana (semi-apes and apes); (8) Bimana
-(man).
-
-The most important advance in the classification of Mammals was made as
-early as 1816 by the eminent anatomist Blainville, who has already been
-mentioned, and who first clearly recognised the three natural main
-groups or sub-classes of Mammals, and distinguished them according to
-the formation of their generative organs as _Ornithodelphia_,
-_Didelphia_, and _Monodelphia_. As this division is now justly
-considered by all scientific zoologists to be the best, on account of
-solid foundation on the history of development, let us here keep to it
-also.
-
-The first sub-class consists of the _Cloacal Animals_, or _Breastless
-animals_, also called _Forked animals_ (Monotrema, or Ornithodelphia).
-This class is now represented only by two species of living mammals,
-both of which are confined to Australia and the neighbouring island of
-Van Diemen's land, namely, the well-known Water Duck-bill
-(Ornithorhynchus paradoxus) with the beak of a bird, and the less known
-Beaked Mole (Echidna hystrix), resembling a hedgehog. Both of these
-curious animals, which are classed in the order of _Beaked Animals_
-(Ornithostoma), are evidently the last surviving remnants of an animal
-group formerly rich in forms, which alone represented the Mammalia in
-the secondary epoch, and out of which the second sub-class, the
-Didelphia, developed later, probably in the Jurassic period.
-Unfortunately, we as yet do not know with certainty of any fossil
-remains of this most ancient primary group of Mammals, which we will
-call _Primary Mammals_ (Promammalia). Yet they possibly comprise the
-oldest of all the fossil Mammalia known, namely, the Microlestes
-antiquus, of which animals, however, we as yet only know some few small
-molar teeth. These have been found in the uppermost strata of the
-Trias, in the Keuper, first in Germany (at Degerloch, near Stuttgart,
-in 1847), later also in England (at Frome), in 1858. Similar teeth have
-lately been found also in the North American Trias, and have been
-described as Dromatherium sylvestre. These remarkable teeth, from the
-characteristic form of which we can conclude that they belonged to an
-insectivorous mammal, are the only remains of mammals as yet found in
-the older secondary strata, namely, in the Trias. It is possible,
-however, that besides these many of the other mammalian teeth found in
-the Jura and Chalk systems, which are still generally ascribed to
-Marsupials, in reality belong to Cloacal Animals. This cannot be decided
-with certainty owing to the absence of the characteristic soft parts. In
-any case, numerous Monotrema, with well-developed teeth and cloaca, must
-have preceded the advent of Marsupial animals.
-
-The designation, "_Cloacal animals_" (Monotrema), has been given to the
-Ornithodelphia on account of the cloaca which distinguishes them from
-all other Mammals; but which on the other hand makes them agree with
-Birds, Reptiles, and Amphibia, in fact, with the lower Vertebrata. The
-formation of the cloaca consists in the last portion of the intestinal
-canal receiving the mouth of the urogenital apparatus, that is, the
-united urinary and genital organs, whereas in all other Mammals
-(Didelphia as well Monodelphia) these organs have an opening distinct
-from that of the rectum. However, in these latter also the cloaca
-formation exists during the first period of their embryonal life, and
-the separation of the two openings takes place only at a later date (in
-man about the twelfth week of development). The Cloacal animals have
-also been called "_Forked animals_," because the collar-bones, by means
-of the breast bone, have become united into one piece, similar to the
-well-known fork-bone, or merry-thought, in birds. In all other Mammals
-the two collar-bones remain separated in front and do not fuse with the
-breast bone. Moreover, the coracoid bones are much more strongly
-developed in the Cloacal animals than in the other Mammalia, and are
-connected with the breast bone.
-
-In many other characteristics also--especially in the formation of their
-internal genital organs, their auricular labyrinth, and their
-brain--Beaked animals are more closely allied to the other Vertebrata
-than to Mammals, so that some naturalists have been inclined to separate
-them from the latter as a special class. However, like all other
-Mammals, they bring forth living young ones, which for a time are
-nourished with milk from the mother. But whereas in all other Mammals
-the milk issues through nipples, or teats, from the mammary glands,
-teats are completely wanting in beaked animals, and the milk comes
-simply out of a flat, sieve-like, perforated patch of the skin. Hence
-they may also be called _Breastless_ or _Teatless animals_ (Amasta).
-
-The curious formation of the beak in the two still living Beaked
-animals, which is connected with the suppression of the teeth, must
-evidently not be looked upon as an essential feature of the whole
-sub-class of Cloacal animals, but as an accidental character of
-adaptation distinguishing the last remnant of the class as much from the
-extinct main group, as the formation of a similar toothless snout
-distinguishes many toothless animals (for instance, the ant-eater) from
-the other placental animals. The unknown, extinct Primary Mammals, or
-Promammalia--which lived during the Trias period, and of which the two
-still living orders of Beaked animals represent but a single
-degenerated branch developed on one side--probably possessed a very
-highly developed jaw like the marsupial animals, which developed from
-them.
-
-_Marsupial_, or _Pouched Animals_ (Didelphia, or Marsupialia), the
-second of the three sub-classes of Mammals, form in every respect--both
-as regards their anatomy and embryology, as well as their genealogy and
-history--the transition between the other sub-classes--the Cloacal and
-Placental Animals. Numerous representatives of this group still exist,
-especially the well-known kangaroos, pouched rats, and pouched dogs; but
-on the whole this sub-class, like the preceding one, is evidently
-approaching its complete extinction, and the living members of the class
-are the last surviving remnants of a large group rich in forms, which
-represented the Mammalia during the more recent secondary and the
-earlier tertiary periods. The Marsupial Animals probably developed
-towards the middle of the Mesolithic epoch (during the Jura) out of a
-branch of the Cloacal Animals, and in the beginning of the Tertiary
-epoch again, the group of Placental Animals arose out of the Marsupials,
-and the latter then succumbed to the former in the struggle for life.
-All the fossil remains of Mammals known to us from the Secondary epoch,
-belong either exclusively to Marsupials, or partly perhaps to Cloacal
-animals. At that time Marsupials seem to have been distributed over the
-whole earth; even in Europe (France and England), well-preserved fossil
-remains of them have been found. On the other hand, the last off-shoots
-of the sub-class now living are confined to a very narrow tract of
-distribution, namely, to Australia, the Australasian, and a small part
-of the Asiatic Archipelago. There are also a few species still living
-in America, but at the present day not a single marsupial animal lives
-on the continent of Asia, Africa, or Europe.
-
-The name of pouched animals is given to the class on account of the
-purse-shaped pouch (marsupium) existing in most instances on the
-abdominal side of the female animals, in which the mother carries about
-her young for a considerable time after their birth. This pouch is
-supported by two characteristic marsupial bones, also existing in
-Cloacal animals, but not in Placental animals. The young Marsupial
-animal is born in a much more imperfect form than the young Placental
-animal, and only attains the same degree of development which the latter
-possesses directly at its birth, after it has developed in the pouch for
-some time. In the case of the giant kangaroo, which attains the height
-of a man, the newly born young one, which has been carried in the
-maternal womb not much longer than five weeks, is not more than an inch
-in length, and only attains its essential development subsequently, in
-the pouch of the mother, where it remains about nine months attached to
-the nipple of the mammary gland.
-
-The different divisions generally distinguished as families in the
-sub-class of Marsupial animals, deserve in reality the rank of
-independent orders, for they differ from one another in manifold
-differentiations of the jaw and limbs, in much the same manner, although
-not so sharply, as the various orders of Placental animals. In part they
-perfectly agree with the latter. It is evident that adaptation to
-similar conditions of life has effected entirely coincident or analogous
-transformations of the original fundamental form in the two sub-classes
-of Marsupials. According to this, about eight orders of Marsupial
-animals may be distinguished, the one half of the main group or legion
-of which are herbivorous, the other half carnivorous. The oldest fossil
-remains of the two legions (if the previously mentioned Microlestes and
-the Dromatherium are not included) occur in the Jurassic strata, namely,
-in the slates of Stonesfield, near Oxford. The slates belong to the
-Bath, or the Lower Oolite formation--strata which lie directly above the
-Lias, the oldest Jura formation. (Compare p. 15.) It is true that the
-remains of Marsupials found in the slates of Stonesfield, as well as
-those which were found later in the Purbeck strata, consist only of
-lower jaws. (Compare p. 29.) But fortunately the lower jaw is just one
-of the most characteristic parts of the skeleton of Marsupials. For it
-is distinguished by a hook-shaped process of the lower corner of the jaw
-turning downwards and backwards, which neither occurs in Placental nor
-in the (still living) Cloacal animals, and from the existence of this
-process on the lower jaws from Stonesfield, we may infer that they
-belonged to Marsupials.
-
-
-SYSTEMATIC SURVEY OF CLOACAL AND MARSUPIAL MAMMALIA.
-
-I. _First Sub-class of Mammalia:_
-
-_Forked or Cloacal Animals (Monotrema, or Ornithodelphia)._
-
-Mammals with Cloaca, without Placenta, with Marsupial Bones.
-
-  ------------------------------------------------------------------------------------
-         I.         }
-  =Primary Mammals= } Unknown extinct Mammalia from the           { (Microlestes?)
-    +Promammalia+   }         Trias Period                        { (Dromatherium?)
-
-         II.        } 1. Aquatic beaked       1. Ornithorhynchida { 1. Ornithorhynchus
-  =Beaked Animals=  }      animals                                {    paradoxus
-  +Ornithostoma+    }   2. Terrestrial        2. Echidnida        { 2. Echidna hystrix
-                    }   beaked animals                            {
-  ------------------------------------------------------------------------------------
-  II. _Second Sub-class of Mammalia:_
-
-  _Pouched or Marsupial Animals (Marsupialia, or Didelphia)._
-
-  Mammals without Cloaca, without Placenta, with Marsupial Bones.
-  ------------------------------------------------------------------------------------
-  _Legions_       |      _Orders_       |    _Systematic Name_  | _Families of the_
-  _of_            |        _of_         |         _of_          |  _Marsupialia._
-  _Marsupialia._  |    _Marsupialia._   |     _the Orders._     |
-  ------------------------------------------------------------------------------------
-                  {   1. Hoofed             1. Barypoda         { 1. Stereognathida
-                  { Marsupial animals                           { 2. Nototherida
-       III.       {                                             { 3. Diprotodontia
-   =Herbivorous=  {
-    =Marsupial=   {  2. Kangaroo            2. Macropoda        { 4. Plagiaulacida
-     =Animals=    { Marsupial animals                           { 5. Halmaturida
-                  { (Leaping pouched                            { 6. Dendrolagida
-   +Marsupialia+  {    animals)
-   +Botanophaga+  {
-                  {  3. Root-eating         3. Rhizophaga       {
-                  { Marsupial animals                           {
-                  { (Gnawing pouched                            { 7. Phascolomyida
-                  {    animals)                                 {
-                  {
-                  {  4. Fruit eating        4. Carpophaga       {
-                  { Marsupial animals                           { 8. Phascolarctida
-                  { (Climbing pouched                           { 9. Phalangistida
-                  {     animals)                                { 10. Petaurida
-
-                  { 5. Insectivorous        5. Cantharophaga    { 11. Thylacotherida
-                  {  Marsupial animals                          { 12. Spalacotherida
-                  { (Primaeval pouched                           { 13. Myrmecobida
-                  {     animals)                                { 14. Peramelida
-       IV.        {
-   =Carnivorous=  { 6. Marsupial animals    6. Edentula         {
-    =Marsupial=   {     poor in teeth                           {
-     =Animals=    {    (Pouched animals                         { 15. Tarsipedina
-                  {      with trunks)                           {
-                  {
-                  { 7. Rapacious marsupial  7. Creophaga        { 16. Dasyurida
-                  {      animals                                { 17. Thylacinida
-   +Marsupialia+  {  (Rapacious pouched                         { 18. Thylacoleonida
-    +Zoophaga+    {      animals)
-                  {
-                  {  8. Ape-footed          8. Pedimana         {
-                  { Marsupial animals                           { 19. Chironectida
-                  { (Pouched animals                            { 20. Didelphyida
-                  {    with hands)
-
-
-SYSTEMATIC SURVEY OF PLACENTAL ANIMALS.
-
-III. _Third Sub-class of Mammalia:_
-
-_Placentalia, or Monodelphia (Placental Animals)._
-
-Mammals without Cloaca, with Placenta, without Marsupial Bones.
-
-
- -----------------------------------------------------------------------------------
-     _Legions of_     |    _Orders of_     |  _Sub-orders of_    |_Systematic Name_
-        _the_         |       _the_        |       _the_         |      _of_
-  _Placental Animals._|_Placental Animals._|_Placental Animals._ | _the Sub-orders._
- -----------------------------------------------------------------------------------
-  III. 1. INDECIDUA. _Placental Animals without Decidua._
- -----------------------------------------------------------------------------------
-          V.          { I. Single-hoofed   { 1. Tapirs              1. Tapiromorpha
-     =Hoofed Animals= {  _Perissodactyla_  { 2. Horses              2. Solidungula
-      +Ungulata+      {
-                      { II. Double-hoofed  { 3. Pigs                3. Choeromorpha
-                      {   _Artiodactyla_   { 4. Ruminating          4. Ruminantia
-
-                      { III. Herbivorous   {
-          VI.         {      Whales        { 5. Sea cows            5. Sirenia
-        =Whales=      {    _Phycoceta_     {
-       +Cetacea+      {
-                      { IV. Carnivorous    { 6. Whales              6. Autoceta
-                      {     Whales         { 7. Zeuglodonta         7. Zeugloceta
-                      {  _Sarcoceta_       {
-
-         VII.         { V. Digging Animals { 8. Ant-eaters          8. Vermilinguia
-       =Animals=      {   _Effodientia_    { 9. Armadilloes         9. Cingulata
-     =poor in teeth=  {
-       +Edentata+     {   VI. Sloths       { 10. Giant Sloths      10. Gravigrada
-                      {   _Bradypoda_      { 11. Dwarf Sloths      11. Tardigrada
- -----------------------------------------------------------------------------------
-  III. 2. DECIDUATA. _Placental Animals with Decidua._
- -----------------------------------------------------------------------------------
-        VIII.         {  VII. Rapacious    {12. Rapacious land     12. Carnivora
-  =Placental Animals= {      Animals       {      animals
-  +Zonoplacentalia+   {     _Carnaria_     {13. Rapacious sea      13. Pinnipedia
-                      {                    {      animals
-                      {
-                      { VIII. False-hoofed {14. Hyrax              14. Lamnungia
-                      {      Animals       {15. Toxodonts          15. Toxodontia
-                      {    _Chelophora_    {16. Dinotheria         16. Gonyognatha
-                      {                    {17. Elephants          17. Proboscidea
-
-
-          XI.         {  IX. Semi-apes     {18. Fingered animals   18. Leptodactyla
-    =Disc Placental=  {   _Prosimiae_       {19. Flying lemur       19. Ptenopleura
-       =Animals=      {                    {20. Long-footed        20. Macrotarsi
-  +Discoplacentalia+  {                    {21. Short-footed       21. Brachytarsi
-                      {
-                      { X. Gnawing Animals {22. Squirrel species   22. Sciuromorpha
-                      {     _Rodentia_     {23. Mouse species      23. Myomorpha
-                      {                    {24. Porcupine species  24. Hystrichomorpha
-                      {                    {25. Hare species       25. Lagomorpha
-                      {
-                      { XI. Insect-eating  {26. With a coecum      26. Menotyphla
-                      {     Animals        {27. Without a          27. Lipotyphla
-                      {   _Insectivora_    {      coecum
-                      {
-                      { XII. Flying Animals{28. Flying foxes       28. Pterocynes
-                      {    _Chiroptera_    {29. Bats               29. Nycterides
-                      {
-                      {    XIII. Apes      { 30. Clawed apes       30. Arctopitheci
-                      {     _Simiae_        { 31. Flat-nosed        31. Platyrrhinae
-                      {                    { 32. Narrow-nosed      32. Catarrhinae
-
-             ----------------------------------------------------------------
-
-                                          =Man=
-                                        +Homines+
-                  Elephants                |
-                 _Proboscidea_             |           Bats
-                       |                   |        _Nycterides_
-    Rock Conies        |                   |             |      Marine animals of prey
-     _Lamnungia_       |             Narrow-nosed        |           _Pinnipedia_
-          |            |              _Catarrhinae_       |                 |
-          |            |                   |        Flying foxes           |
-          \------v-----/     Flat-nosed    |         _Pterocynes_          |
-          Pseudo-hoofed      _Platyrrhinae_ |       =Flying Animals=        |
-            _Chelophora_          |        |         +Chiroptera+          |
-                  |               |        |             |                 |
-                  |               \----v---/             |       Land animals of prey
-                  |                  =Apes=              |            _Carnivora_
-           =Gnawing Animals=         +Simiae+             |         =Animals of Prey=
-              +Rodentia+               |                 |            +Carnaria+
-                  |  Fingered animals  |     Lemurs      |                 |
-                  |    _Leptodactyla_  |   _Brachytarsi_ |                 |
-      True        |          |         |        |        \-------v---------/
-     whales       |          |         |        |          Insect eaters
-    _Sarcoceta_   \-----v----/         \---v----/           _Insectivora_
-        |               |                  |                     |
-        |               \------------------v---------------------/
-     Sea cows                           Semi-apes
-     _Sirenia_                          _Prosimiae_
-     =Whales=                        =Deciduous Animals=
-     +Cetacea+                           +Deciduata+
-        |          Poor in teeth            |
-  =Hoofed Animals=  _Edentata_              |
-     +Ungulata+          |                  |
-        |                |                  |
-        \-------v--------/                  |
-           =Indeciduous=                    |
-           +Indeciduata+                    |
-                |                           |
-                \-------------v-------------/
-                     =Placental Animals=
-                         +Placentalia+
-    Herbivorous marsupials    |     Carnivorous marsupials
-    _Marsupialia botanophaga_ |      _Marsupialia zoophaga_
-               |              |                 |
-               \--------------v-----------------/
-                         =Marsupial=
-                        +Marsupialia+
-    Beaked animals            |
-     _Ornithostoma_           |
-           |                  |
-           \---------v--------/
-             Primary mammals
-               _Promammalia_
-             =Cloacal Animals=
-                +Monotrema+
-
-
-Of _Herbivorous marsupials_ (Botanophaga), only two fossils are as yet
-known from the Jura, namely, the Stereognathus ooliticus, from the
-slates of Stonesfield (Lower Oolite), and the Plagiaulax Becklesii, from
-the middle Purbeck strata (Upper Oolite). But in Australia there are
-gigantic fossil remains of extinct herbivorous Marsupials from the
-diluvial period (Diprotodon and Nototherium) which were far larger than
-the largest of the still living Marsupials. The Diprotodon Australis,
-whose skull alone is three feet long, exceeded even the river-horse, or
-Hippopotamus, in size and upon the whole resembled it in the unwieldy
-and clumsy form of body. This extinct group, which probably corresponded
-with the gigantic placental hoofed animals of the present day--the
-hippopotami and rhinoceroses--may be called Hoofed Marsupials
-(Barypoda). Closely allied to them is the order of kangaroos, or Leaping
-Marsupials (Macropoda), which all have seen in zoological gardens. In
-their shortened fore legs, their very lengthened hind legs, and very
-strong tail, which serves as a jumping pole, they correspond with the
-leaping mice in the class of Rodents. Their jaw, however, resembles that
-of horses, and their complex stomach that of Ruminants. A third order of
-Herbivorous Marsupials corresponds in its jaws to Rodents, and in its
-subterranean mode of life, especially, to digging mice. Hence they may
-be termed Rodent Marsupials, or root-eating pouched animals
-(Rhizophaga). They are now represented only by the Australian wombat
-(Phascolomys). A fourth and last order of Herbivorous Marsupials is
-formed by the climbing or Fruit-eating Marsupials (Carpophaga), whose
-mode of life and structure resembles partly that of squirrels, partly
-that of apes (Phalangista, Phascolarctus).
-
-The second legion of Marsupials, the _Carnivorous Marsupials_
-(Zoophaga), is likewise divided into four main groups or orders. The
-most ancient of these is that of the primaeval, or Insectivorous
-Marsupials (Cantharophaga). It probably includes the primary forms of
-the whole legion, and possibly also those of the whole sub-class. At
-least, all the lower jaws from Stonesfield (with the exception of the
-Stereognathus) belong to Insectivorous Marsupials, and the still living
-Myrmecobius is their nearest relative. But some of those oolitic
-Primaeval Marsupials possessed a larger number of teeth than all the
-other known mammals, for each half of the lower jaw of the
-Thylacotherium contained sixteen teeth (three incisors, one canine
-tooth, six pseudo, and six genuine molars). If the upper jaw, which is
-unknown, had as many teeth, then the Thylacotherium had no less than
-sixty-four teeth, just double the number possessed by man. The Primaeval
-Marsupials correspond, on the whole, with the Insectivora among
-Placental animals, which order includes hedgehogs, moles, and
-shrew-mice. A second order, which has probably developed out of a branch
-of the last, consists of the Snouted, or Toothless Marsupials
-(Edentula), which resemble the Toothless animals, or Edentata, among the
-Placental animals by their tube-shaped snout, their degenerated jaws,
-and their corresponding mode of life. On the other hand, the mode of
-life and formation of the jaws of Rapacious marsupials (Creophaga)
-correspond with those of the genuine Beasts of Prey, or Carnivora, among
-Placental animals. This order includes the pouched marten (Dasyurus) and
-the pouched wolf (Thylacinus) in Australia. Although the latter attains
-to the size of a wolf, it is but a dwarf in comparison with the extinct
-Australian pouched lions (Thylacoleo) which were at least as large as a
-lion, and possessed huge canine teeth more than two inches in length.
-Finally, the eighth and last order is formed by the marsupials with
-hands, or the Ape-footed Pouched animals (Pedimana), which live both in
-Australia and America. They are frequently kept in zoological gardens,
-especially the different species of the genus Didelphys, and are known
-by the name of pouched rats, bush rats, or opossums. The thumb on their
-hinder feet is opposable to the four other toes, as in a hand, and by
-this they are directly allied to the Semi-apes, or Prosimia, among
-Placental animals. It is possible that these latter are really next akin
-to the marsupials with hands, and that they have developed out of their
-long since extinct ancestors.
-
-It is very difficult to discover the genealogy of Marsupials, and this
-more especially because we are but very imperfectly acquainted with the
-whole sub-class; and the Marsupials of the present day are evidently
-only the last remnants of a group that was at one time rich in forms. It
-is possible that Marsupials with hands, those with snouts, as well as
-rapacious Marsupials, developed as three diverging branches out of the
-common primary group of Primaeval Marsupials. In a similar manner, on the
-other hand, the rodent, leaping, and hoofed Marsupials have perhaps
-arisen as three diverging branches out of the common herbivorous primary
-group, that is, out of the Climbing Marsupials. Climbing and Primaeval
-Marsupials might, however, be two diverging branches of the common
-primary forms of all Marsupials, that is, of the _Primary Marsupials_
-(Prodidelphia), which originated during the older secondary period out
-of Cloacal animals.
-
-The third and last sub-class of mammals comprises the _Placental
-animals_, or _Placentals_ (Monodelphia, or Placentalia). It is by far
-the most important, comprehensive, and most perfect of the three
-sub-classes; for the class includes all the known mammalia, with the
-exception of Marsupials and Beaked animals. Man also belongs to this
-sub-class, and has developed out of its lower members.
-
-Placental animals, as their name indicates, are distinguished from all
-other mammals, more especially by the formation of a so called
-_placenta_. This is a very peculiar and remarkable organ, which plays
-an exceedingly important part in nourishing the young one developing in
-the maternal body. The placenta (also called after-birth) is a soft,
-spongy, red body, which differs very much in form and size, but which
-consists for the most part of an intricate network of veins and blood
-vessels. Its importance lies in the exchange of substance between the
-nutritive blood of the maternal womb, or uterus, and the body of the
-germ, or embryo. (See vol. i. p. 298.) This very important organ is
-developed neither in marsupials nor in beaked animals. But placental
-animals are also distinguished from these two sub-classes by many other
-peculiarities, thus more especially by the absence of marsupial bones,
-by the higher development of the internal sexual organs, and by the more
-perfect development of the brain, especially of the so-called callous
-body or beam (_corpus callosum_), which, as the intermediate commissure,
-or transverse bridge, connects the two hemispheres of the large brain
-with each other. Placental animals also do not possess the peculiar
-hooked process of the lower jaw which characterizes Marsupials. The
-following classification (p. 246) of the most important characteristics
-of the three sub-classes will best explain how Marsupials, in these
-anatomical respects, stand midway between Cloacal and Placental animals.
-
-Placental animals are more variously differentiated and perfected, and
-this, moreover, in a far higher degree, than Marsupials, and they have,
-on this account, long since been arranged into a number of orders,
-differing principally in the formation of the jaws and feet. But what is
-even of more importance than these, is the different development of the
-placenta, and the manner of its connection with the maternal uterus.
-For in the three lower orders of Placental animals, in Hoofed animals,
-Whales, and Toothless animals, the peculiar spongy membrane, which is
-called the _deciduous membrane_, or _decidua_, and which connects the
-maternal and the foetal portions of the placenta, does _not_ become
-developed. This takes place exclusively in the seven higher orders of
-Placental animals, and we may, therefore, according to Huxley, class
-them in the main group of _Deciduata_, or animals with _decidua_. They
-are contrasted with the three first-mentioned legions of indeciduous
-animals, or _Indeciduata_.
-
-
-  ---------------------------+-------------------+-------------------+-------------------
-                             | _Cloacal Animals_ | _Pouched Animals_ |_Placental Animals_
-     _Three Sub-Classes_     |    MONOTREMA      |  MARSUPIALIA      |   PLACENTALIA
-             _of_            |      _or_         |      _or_         |       _or_
-          _Mammals._         |  ORNITHODELPHIA   |   DIDELPHIA       |   MONODELPHIA
-  ---------------------------+-------------------+-------------------+-------------------
-  1. Cloaca formation        |    Constant       |   Embryonal       |    Embryonal
-                             |                   |                   |
-  2. Nipples of the pectoral |    Wanting        |   Existing        |    Existing
-  glands, or milk            |                   |                   |
-  warts                      |                   |                   |
-                             |                   |                   |
-  3. Fore collar bones,      |    United         |   Not united      |    Not united
-  or clavicles, grown        |                   |                   |
-  together in the middle,    |                   |                   |
-  with the breast bone,      |                   |                   |
-  and forming a forked       |                   |                   |
-  bone                       |                   |                   |
-                             |                   |                   |
-  4. Marsupial bones         |    Existing       |    Existing       |     Wanting
-                             |                   |                   |
-  5. _Corpus callosum_ of    |     Feebly        |     Feebly        | Strongly developed
-  the brain                  |   developed       |   developed       |
-                             |                   |                   |
-  6. Placenta                |    Wanting        |    Wanting        |    Existing
-  ---------------------------+-------------------+-------------------+-------------------
-
-
-But in the various orders of Placental animals the placenta differs not
-only in important internal differences of structure, which are connected
-with the absence or the presence of a decidua, but also in the external
-form of the placenta itself. In the Indeciduata it consists, in most
-cases, of numerous, single, scattered bunches or tufts of vessels, and
-hence this group may be called _tufted placental animals_
-(Villiplacentalia). In the Deciduata, however, the single tufts of
-vessels are united into a cake, which appears in two different forms. In
-the one case it surrounds the embryo in the form of a closed band or
-ring, so that only the two poles of the oval egg bladder are free of
-tufts; this is the case in animals of prey (Carnaria) and the
-pseudo-hoofed animals (Chelophora), which may consequently be comprised
-as _girdled-placental animals_ (Zonoplacentalia). In the other
-Deciduata, to which man also belongs, the placenta is a simple round
-disc, and we therefore call them _disc-placentals_ (Discoplacentalia).
-This group includes the five orders of Semi-apes, Gnawing animals,
-Insectivora, Bats, and Apes, from the latter of which, in the zoological
-system, man cannot be separated.
-
-It may be considered as quite certain, from reasons based upon their
-comparative anatomy and their history of development, that Placental
-animals first developed out of Marsupials, and that this very important
-development--the first origin of the placenta--probably took place in
-the beginning of the tertiary epoch, during the eocene period. But one
-of the most difficult questions in the genealogy of animals is the
-important consideration whether all Placental animals have arisen out of
-one or out of several distinct branches of Marsupials; in other words,
-whether the origin of the placenta occurred but once, or several times.
-
-When, in my General Morphology, I for the first time endeavoured to
-establish the pedigree of Mammals, I here, as in most cases, preferred
-the monophyletic, or one-rooted, to the polyphyletic, or many-rooted,
-hypothesis of descent. I assumed that all Placental animals were derived
-from a single form of Marsupial animal, which, for the first time, began
-to form a placenta. In this case the Villiplacentals, Zonoplacentals,
-and Discoplacentals would perhaps have to be considered as three
-diverging branches of the common primary form of Placentals, or it might
-also be conceived that the two latter, the Deciduata, had developed only
-at a later period out of the Indeciduata, which on their part had arisen
-directly out of the Marsupials. However, there are also important
-reasons for the alternative; namely, that several groups of Placentals,
-differing from the beginning, arose out of several distinct groups of
-Marsupials, so that the placenta itself was formed several times
-independently. This opinion is maintained by Huxley, the most eminent
-English zoologist, and by many others. In this case the Indeciduata and
-the Deciduata would perhaps have to be considered as two completely
-distinct groups; then the order of Hoofed animals, as the primary group
-of the Indeciduata, might be supposed to have originated out of the
-Marsupial hoofed animals (Barypoda). Among the Deciduata, on the other
-hand, the order of Semi-apes, as the common primary form of the other
-orders, might possibly have arisen out of Handed Marsupials (Pedimana).
-But it is also conceivable that the Deciduata themselves have arisen out
-of several different orders of Marsupials, Animals of Prey out of
-Rapacious Marsupials, Gnawing animals out of Gnawing Marsupials,
-Semi-apes out of Handed Marsupials, etc. As we do not at present possess
-sufficient empiric material to solve this most difficult question, we
-must leave it and turn our attention to the history of the different
-orders of Placental animals, whose pedigree can often be very accurately
-established in detail.
-
-We must, as already remarked, consider the order of _Hoofed animals_
-(Ungulata) as the primary group of the Indeciduata, or Tuft-placentals;
-the two other orders, Whales and Toothless animals, developed out of
-them, as two diverging groups, probably only at a later period, by
-adaptation to very different modes of life. But it is also possible that
-the animals poor in teeth (Edentata) may be of quite a different origin.
-
-Hoofed animals are in many respects among the most important and the
-most interesting Mammals. They distinctly show that a true understanding
-of the natural relationship of animals can never be revealed to us
-merely by the study of living forms, but in all cases only by an equal
-consideration of their extinct and fossil blood-relations and ancestors.
-If, as is usually done, only the living Hoofed animals are taken into
-consideration, it seems quite natural to divide them into three entirely
-distinct orders, namely: (1) Horses, or _Single-hoofed animals_
-(Solidungula, or Equina); (2) Ruminating animals, or _Double-hoofed_
-(Bisulca, or Ruminantia); and (3) Thick-skinned, or _Many-hoofed_
-(Multungula, or Pachyderma). But as soon as the extinct Hoofed animals
-of the tertiary period are taken into consideration--of which animals we
-possess very numerous and important remains--it is seen that this
-division, but more especially the limitation of the Thick-skinned
-animals, is completely artificial, and that these three groups are
-merely top branches lopped from the pedigree of Hoofed animals, which
-are most closely connected by extinct intermediate forms. The one half
-of the Thick-skinned animals--rhinoceroses, tapirs, and
-palaeotheria--manifest the closest relationships to horses, and have like
-them odd-toed feet; whereas the other half of the Thick-skinned
-animals--pigs, hippopotami, and anoplotheria--on account of their
-double-toed feet are much more closely allied to ruminating animals than
-to the former. Hence we must, in the first place, among Hoofed animals
-distinguish the two orders of Paired-hoofs and Odd-hoofs, as two natural
-groups, which developed as diverging branches out of the old tertiary
-primary group of Primary Hoofed animals, or Prochela.
-
-The order of _Odd-hoofed animals_ (Perissodactyla) comprises those
-Ungulata in which the middle (or third) toe of the foot is much more
-strongly developed than the others, so that it forms the actual centre
-of the hoof. This order includes the very ancient, common, primary group
-of all Hoofed animals, that is, the _Primary-hoofed animals_ (Prochela),
-which are found in a fossil state in the oldest Eocene strata
-(Lophiodon, Coryphodon, Pliolophus). Directly allied to this group is
-that branch which is the actual primary form of the Odd-hoofed animals,
-namely, the _Palaeotheria_, fossils of which occur in the upper Eocene
-and lower Miocene. Out of the Palaeotheria, at a later period, the
-rhinoceroses (Nasicornia) and rhinoceros-horses (Elasmotherida) on the
-one hand, and the tapirs, lama-tapirs, and primaeval horses, on the
-other, developed as two diverging branches. The long since extinct
-primaeval horses, or Anchitheria, formed the transition from the
-Palaeotheria and tapirs to the Miocene horses, or hipparions, which are
-closely allied to the genuine living horses.
-
-The second main group of Hoofed animals, the order of _Pair-hoofed
-animals_ (Artiodactyla), comprises those hoofed animals in which the
-middle (third) and fourth toe of the foot are almost equally developed,
-so that the space between the two forms the central line of the entire
-foot. The order is divided into two sub-orders--the Pig-shaped and the
-Cud-chewing, or Ruminating. The _Pig-shaped_ (Choeromorpha) comprise in
-the first place the other branch of Primary-Hoofed-animals, the
-_Anoplotheria_, which we consider as the common primary form of all
-Pair-hoofed animals, or Artiodactyla (Dichobune, etc.). Out of the
-Anoplotheria arose, as two diverging branches, the primaeval swine, or
-Anthracotheria, on the one hand, forming the transition to swine and
-river-horses, and the Xiphodonta on the other hand, forming the
-transition to Ruminating animals. The oldest _Ruminating animals_
-(Ruminantia) are the Primaeval Stags, or Dremotheria, out of which,
-possibly, the stag-shaped (Elaphia), the hollow-horned (Cavicornia), and
-camels (Tylopoda), have developed as three diverging branches. Yet these
-latter are, in many respects, more allied to the Odd-hoofs than to the
-genuine Pair-hoofs. The accompanying systematic survey on p. 252, will
-show how the numerous families of Hoofed animals are grouped, in
-correspondence with this genealogical hypothesis.
-
-
-  SYSTEMATIC SURVEY
-
-  _Of the Sections and Families of Hoofed Animals, or Ungulata._
-
-  (N.B. Those families that are extinct are marked with an asterisk.)
-
-
-  ----------------+--------------------------------+------------------------+-------------------
-      _Orders_    |                                |                        |
-        _of_      |          _Sections_            |    _Families_          | _Systematic Name_
-      _Hoofed_    |             _of_               |       _of_             |        _of_
-     _animals._   |       _Hoofed Animals._        |  _Hoofed Animals._     |   _the Families._
-  ----------------+----------------------------=---+------------------------+-------------------
-        I.         {  I. Primary Hoofed              {  1. Lophiodonta        1. Lophiodontia*
-    =Odd-toed=     {       Animals.*                 {  2. Pliolophida        2. Pliolophida*
-     =Hoofed=      {      _Prochela_
-    =Animals=      {                                 {  3. Primary            3. Palaeotherida*
-                   {                                 {    Odd-hoofs
-    +Ungulata+     {  II. Tapir-shaped               {  4. Lama-tapirs        4. Macrauchenida*
-                   {   _Tapiromorpha_                {  5. Tapirs             5. Tapirida
-  +Perissodactyla+ {                                 {  6. Rhinoceroses       6. Nasicornia
-                   {                                 {  7. Rhinoceros-horses  7. Elasmotherida*
-                   {
-                   {  III. Single-hoofs              {  8. Primaeval           8. Anchitherida*
-                   {    _Solidungula_                {     horses
-                   {                                 {  9. Horses             9. Equina
-
-                   {                                 { 10. Primary           10. Anoplotherida*
-                   {                                 {    Pair-hoofs
-                   {                                 { 11. Primaeval          11. Anthracotherida*
-                   {  IV. Pig-shaped                 {    pigs
-                   {  _Choeromorpha_                 { 12. Pigs              12. Setigera
-                   {                                 { 13. River horses      13. Obesa
-                   {                                 { 14. Primaeval          14. Xiphodontia*
-                   {                                 {    ruminants
-                   {
-                   {              {                  {    {15. Primaeval      15. Dremotherida*
-                   {              {                  {    {     deer
-        II.        {              { A. Stag-shaped   { a. {16. Pseudo        16. Tragulida
-    =Pair-toed=    {              {  _Elaphia_       {    {   musk deer
-     =Hoofed=      {              {                  {
-    =Animals=      {              {                  { b. {17. Musk deer     17. Moschida
-                   {              {                  {    {18. Deer          18. Cervina
-   +Ungulata+      {              {                  {
-                   {    V.        {                  { c. {19. Primaeval      19. Sivatherida*
-  +Artiodactyla+   { Ruminating   {                  {    {  giraffes
-                   { animals      {                  {    {20. Giraffes      20. Devexa
-                   { _Ruminantia_ {
-                   {              {                  {    {21. Primaeval      21. Antilocaprina*
-                   {              {                  { d. {  gazelles
-                   {              {                  {    {22. Gazelles      22. Antilopina
-                   {              {                  {
-                   {              { B. Hollow-horned {    {23. Goats         23. Caprina
-                   {              {  _Caricornia_    { e. {24. Sheep         24. Ovina
-                   {              {                  {    {25. Oxen          25. Bovina
-                   {              {
-                   {              { C. Pad-footed    { 26. Lamas             26. Auchenida
-                   {              {  _Tylopoda_      { 27. Camels            27. Camelida
-
-             ----------------------------------------------------------------
-
-    Oxen                       Giraffes
-      |                            |
-      |    Sheep         Deer      |
-      |      |             |       |
-      |      |             |       |
-      \--v---/  Goats      \---v---/  Musk deer              Horses
-         |        |            |          |                  _Equi_
-         |        |            |          |                     |
-         \---v-----/ Antelopes |          |   Camels            |
-             |           |     \----v-----/ and Lamas  Intermediate horses
-             |           |      Deer-shaped  _Tylopoda_    _Hippariones_
-             \-----v------/      _Elaphia_       |              |
-             Hollow-horned          |            |              |
-             _Cavicornia_           |            |              |
-                   |                |            |              |
-                   |                |            |       Primaeval horses
-                   \-------v--------/            |       _Anchitherida_
-                     Primaeval deer               |              |
-                     _Dremotherida_              |              |
-                           |                     |       =Single Hoofers=
-                           |                     |       +Solidungula+
-                           \--v------------------/              |
-                      =Ruminating Animals=                      |
-                         +Ruminantia+                           |
-  Sea-oxen                    |      Tapirs                     |
-  _Sirenia_                   |     _Tapirida_                  |
-     |     River-horses       |         |          Lama-tapirs  |
-     |       _Obesa_          |         |        _Macrauchenida_|
-     |          |             |         |                 |     |
-     |          |    Pigs     |         |                 |     |
-     \----v-----/ _Setigera_  |         \--------------v--/     |
-          |            |      |                        |        |
-          |            |      |      Rhinoceros-horses |        |
-          |            |      |       _Elasmotherida_  |        |
-          |            |      |              |         |        |
-         \------v-------/     |              |         |        |
-           Primaeval pigs      | Rhinoceruses |         |        |
-         _Anthracotherida_    | _Nasicornia_ |         \---v-----/
-                |             |      |       |             |
-                | Primaeval ruminants |       |             |
-                |   _Xiphodontia_    \---v---/             |
-                |             |          |                 |
-                |             |          |                 |
-                \------v------/          \--------v--------/
-               =Primary Pair-hoofs=         =Primary Odd-hoofs=
-                +Anoplotherida+             +Palaeotherida+
-                       |                          |
-                       |                          |
-                       \------------v-------------/
-                                _Prochela_
-                         Primary-hoofed-animals
-                     (_Lophiodontia_ and _Pliophida_)
-                                    |
-                                    |
-                      (Hoofed marsupials? _Barypoda?_)
-
-
-It is probable that the remarkable legion of _Whales_ (Cetacea)
-originated out of Hoofed animals, which accustomed themselves
-exclusively to an aquatic life, and thereby became transformed into the
-shape of fish. Although these animals seem externally very like many
-genuine Fish, yet they are, as even Aristotle perceived, genuine
-Mammals. By their whole internal structure--in so far as it has not
-become changed by adaptation to an aquatic life--they, of all known
-Mammals, are most closely allied to Hoofed animals, and more especially
-agree with them in the absence of the decidua and in the tufted
-placenta. Even at the present day the river-horse (Hippopotamus)
-constitutes a kind of transition form to the Sea Cows (Sirenia), and
-from this it seems most probable that the extinct primary forms of the
-Cetacea are most closely allied to the Sea Cows of the present day, and
-that they developed out of Pair-hoofed animals, which were related to
-the hippopotamus. Out of the order of _Herbivorous whales_
-(Phycoceta)--to which the sea cows belong, and which accordingly, very
-probably, contain the primary forms of the legion--the other order of
-_Carnivorous whales_ (Sarcoceta) appears to have developed at a later
-period. But Huxley thinks that these latter were of quite a different
-origin, and that they arose out of the Carnaria through the Seals. Among
-the Sarcoceta, the extinct gigantic Zeuglodonta (Zeugloceta)--whose
-fossil skeletons some time ago excited great interest, it being thought
-that they were "sea serpents"--are probably only a peculiarly developed
-lateral branch of genuine whales (Autoceta), which comprise, besides the
-colossal whalebone whales, the cachalot or spermaceti whales, dolphins,
-narwhals, porpoises, etc.
-
-The third legion of the Indeciduata, or Sparsi-placentalia, comprises
-the strange group of the animals _poor in teeth_ (Edentata); it is
-composed of the two orders of burrowers and sloths. The order of
-_Burrowers_ (Effodientia) consists of the two sub-orders of _ant eaters_
-(Vermilinguia), to which the scaled animals also belong, and the _girdle
-animals_ (Cingulata), which were formerly represented by the gigantic
-Glyptodons. The order of _Sloths_ (Tardigrada) consists of the two
-sub-orders of the small, still living _dwarf sloths_ (Bradypoda), and
-of the extinct unwieldy _giant sloths_ (Gravigrada). The enormous fossil
-remains of these colossal herbivora suggest that the whole legion is
-becoming extinct, and that the Edentata of the present day are but a
-poor remnant of the mighty order of the diluvial period. The close
-relations between the still living South American Edentata and the
-extinct gigantic forms which are found beside the latter on the same
-part of the globe, made such an impression upon Darwin on his first
-visit to South America, that they even then suggested to him the
-fundamental idea of the Theory of Descent. (See above, vol. i. p. 134.)
-But it is precisely the genealogy of this legion which is most
-difficult. The Edentata are perhaps nothing but a peculiarly developed
-lateral branch of the Ungulata; but it may also be that their root lies
-in quite another direction.
-
-We now leave the first main group of Placental animals, the Indeciduata,
-and turn to the second main group, namely, the Deciduata, or animals
-with decidua, which are distinguished from the former by possessing a
-deciduous membrane, or decidua, during their embryonal life. We here
-meet with a very remarkable small group of animals, for the most part
-extinct, and which probably were the old tertiary (or eocene) ancestors
-of man. These are the Semi-apes, or Lemurs (Prosimiae); these curious
-animals are probably the but little changed descendants of the primaeval
-group of Placentalia which we have to consider as the common primary
-form of all Deciduata. They have hitherto been classed together in the
-same order with Apes which Blumenbach called Quadrumana (four-handed).
-However, I regard them as entirely distinct from these, not merely
-because they differ from all Apes, much more than do the most different
-Apes from one another, but also because they comprise most interesting
-transitional forms leading to the other orders of Deciduata. I conclude
-from this that the few still living Semi-apes, which moreover differ
-very much among one another, are the last surviving remnants of a
-primary group now almost extinct, but which was at one time rich in
-forms, and out of which all the other Deciduata (possibly with the
-single exception of Beasts of Prey, and Pseudo-hoofed animals) have
-developed as diverging branches. The old primary group of Semi-apes has
-probably developed out of Handed or Ape-footed Marsupials (Pedimana),
-which are surprisingly like them in the transformation of their hinder
-feet into grasping hands. The primaeval primary forms themselves (which
-probably originated in the eocene period) are of course long since
-extinct, as are also the greater portion of the transition-forms between
-them and all the other orders of Deciduata. However, individual remnants
-of the latter are preserved among the Semi-apes of the present day.
-Among these, the remarkable Finger-animal of Madagascar (Chiromys
-madagascariensis) constitutes the remnant of the group of the
-Leptodactyla and the transition to Rodents. The strange flying lemur in
-the South Sea and Sunda islands (Galeopithecus), the only remnant of the
-group of Pteropleura, forms a perfect intermediate stage between
-Semi-apes and Bats. The long-footed Semi-apes (Tarsius, Otolicnus)
-constitute the last remnant of that primary branch (Macrotarsi) out of
-which the Insectivora developed. The short-footed forms (Brachytarsi)
-are the medium of connection between them and genuine Apes. The
-Short-footed Semi-apes comprise the long-tailed Lemur, the short-tailed
-Lichanotus, and the Stenops, the latter of which seems to be very
-closely allied to the probable ancestors of man among the Semi-apes. The
-short-footed as well as the long-footed Prosimiae live widely distributed
-over the islands of southern Asia and Africa, more especially in
-Madagascar; some live also on the continent of Africa. No Semi-ape,
-either living or in a fossil state, has as yet been found in America.
-They all lead a solitary, nocturnal kind of life, and climb about on
-trees. (Compare vol. i. p. 361.)
-
-Among the six remaining orders of Deciduata, all of which are probably
-derived from long since extinct Semi-apes, the order of _Gnawing
-animals_ (Rodentia), which is rich in forms, has remained at the lowest
-stage. Among these the _squirrel-like_ animals (Sciuromorpha) stand
-nearest akin to the Pedimanous Marsupials. Out of this primary group the
-_mouse-like_ animals (Myomorpha) and the _porcupine-like_ animals
-(Hystricomorpha) developed probably as two diverging branches, the
-former of which are directly connected with the squirrel-like animals,
-by the eocene Myoxida, the latter by the eocene Psammoryctida. The
-fourth sub-order, the _hare-like_ animals (Lagomorpha), probably
-developed only at a later period out of one of the other three
-sub-orders.
-
-Very closely allied to the Rodentia is the remarkable order of
-_Pseudo-hoofed animals_ (Chelophora). Of these there now live but two
-genera, indigenous to Asia and Africa, namely, Elephants (Elephas), and
-Rock Conies (Hyrax). Both have hitherto generally been classed among
-real Hoofed animals, or Ungulata, with which they agree in the formation
-of the feet. But an identical transformation of nails or claws into
-hoofs occurs also in genuine Rodentia and in certain hoofed Rodentia
-(Subungulata) which live exclusively in South America. Beside smaller
-forms (for example, guinea pigs and gold hares) the Subungulata also
-include the largest of all Rodentia, namely, the Capybara Rats, which
-are about four feet in length. The Rock Conies, which are externally
-very nearly akin to Rodents, especially to the hoofed Rodents, were
-formerly classed among Rodentia by some celebrated zoologists, as an
-especial sub-class (Lamnungia). Elephants, on the other hand, when not
-classed among Hoofed animals, were generally considered as the
-representatives of a special order which were called Trunked animals
-(Proboscidea). But the formation of the placentas of Elephants and of
-Hyrax agree in a remarkable manner, and are entirely distinct from those
-of Hoofed animals. These latter never possess a decidua, whereas
-Elephants and Hyrax are genuine Deciduata. Their placenta is indeed not
-of the form of a disc, but of a girdle, as in the case of Animals of
-Prey; it is very possible that the girdle-shaped placenta is but a
-secondary development of the discoplacenta. Thus, then, it might be
-thought that the Pseudo-hoofed animals have developed out of a branch of
-the Rodentia, and in a similar manner perhaps the Carnivora out of a
-branch of the Insectivora. At all events, Elephants and Hyrax in many
-respects, especially in the formation of important skeletal parts, of
-the limbs, etc., are more closely allied to the Rodentia, and more
-especially to hoofed Rodentia, than to genuine Hoofed animals. Moreover
-several extinct forms, especially the remarkable South American
-Arrow-toothed animals (Toxodontia), stand in many respects midway
-between Elephants and Rodentia. That the still living Elephants and
-Hyrax are but the last survivors of a group of Pseudo-hoofed animals,
-which was once rich in forms, is proved not only by the very numerous
-fossil species of Elephants and Mastodon (some of which are even larger,
-others also much smaller than the Elephants of the present day), but
-also by the remarkable miocene _Dinotheria_ (Gonyognatha), between which
-and their next kindred, the Elephants, there must be a long series of
-unknown connecting intermediate forms. Taking all things into
-consideration, the most probable hypothesis which can be established at
-present as to the origin and the relationship of Elephants, Dinotheria,
-Toxodon, and Hyrax is, that they are the last survivors of a group of
-Pseudo-hoofed animals rich in forms, which developed out of the
-Rodentia, and probably out of relatives of the Subungulata.
-
-The order of _Insect Eaters_ (Insectivora) is a very ancient group, and
-is next akin to the common extinct primary form of the Deciduata, as
-well as to the Semi-apes of the present day. It has probably developed
-out of Semi-apes which were closely allied to the Long-footed Lemurs
-(Macrotarsi) of the present day. It is separated into two orders,
-Menotyphla and Lipotyphla; the Menotyphla are probably the older of the
-two, and are distinguished from the Lipotyphla by possessing an
-intestinal coecum, or typhlon. The Menotyphla include the climbing
-Tupajas of the Sunda Isles, and the leaping Macroscelides of Africa. The
-Lipotyphla are represented in our country by shrew mice, moles, and
-hedgehogs. The Insectivora, in the formation of their jaws and their
-mode of life, are nearly akin to Carnivora, but are, on the other hand,
-by their discoplacentas and by their large seminal vesicles, allied to
-Rodents.
-
-It is probable that the order of _Rapacious animals_ (Carnaria)
-developed out of a long since extinct branch of Insectivora, at the
-beginning of the Eocene period. It is a natural group, very rich in
-forms, but still of very uniform organization. The Rapacious animals are
-sometimes also called Girdle-placentals (Zonoplacentals), although the
-Pseudo-hoofed animals (Chelophora), in the same way, also deserve this
-designation. But as the latter, in other respects, are more closely
-allied to the Rodentia than to Carnaria, we have already discussed them
-in connection with the former. Animals of prey are divided into two,
-externally very different, but internally very closely related,
-sub-orders, namely, Land animals of prey and Marine animals of prey. The
-_Land animals of prey_ (Carnivora) comprise bears, dogs, cats, etc.,
-whose pedigree can be approximately guessed at by means of many extinct
-intermediate forms. The _Marine animals of prey_, or _Seals_
-(Pinnipedia), comprise sea bears, sea dogs, sea lions, and walruses.
-Although marine animals of prey appear externally very unlike land
-animals of prey, yet by their internal structure, their jaw and their
-peculiar girdle-shaped placenta, they are very nearly akin to them, and
-have evidently originated out of a branch of them, probably out of a
-kind of weasel (Mustelina). Even at the present day the fish otters
-(Lutra), and still more so the sea otters (Enhydris), present a direct
-form of transition to Seals, and clearly show how the bodies of land
-Carnivora are transformed into the shape of a Seal, by adaptation to an
-aquatic life, and how the steering fins of marine rapacious animals have
-arisen out of the legs of the former. The latter consequently stand in
-the same relation to the former as do the Whales to Hoofed animals
-among the Indeciduata. In the same way as the river-horse at present
-stands midway between the extreme branches of oxen and sea oxen, the sea
-otter still forms a surviving intermediate stage between the widely
-separated branches of dogs and sea dogs. In both cases the complete
-transformation of the external form, consequent upon adaptation to
-entirely different conditions of life, has not been able to efface the
-solid foundation of the inherited internal peculiarities.
-
-According to Huxley's opinion, which has already been quoted, only the
-Herbivorous Whales (Sirenia) are derived from Hoofed animals; on the
-other hand, the Carnivorous Cetacea (Sarcoceta) are derived from the
-marine animals of prey; the Zeuglodonts would form a transition between
-the two latter. But in this case it would be difficult to understand the
-close anatomical relations which exist between the Herbivorous and
-Carnivorous Cetacea. The strange peculiarities in the internal and
-external structure which so strikingly distinguish the two groups from
-all other mammals would then have to be regarded only as _analogies_
-(caused by the same kinds of adaptation), not as _homologies_
-(transmitted from a common primary form). The latter, however, strikes
-me as being by far the more probable, and hence I have left all the
-Cetacea among the Indeciduata as one group of kindred origin.
-
-The remarkable order of _Flying Mammals_, or _Bats_ (Chiroptera), stands
-near to the Carnaria as well as to the Insectivora. It has become
-strikingly transformed by adaptation to a flying mode of life, just as
-marine animals of prey have become modified by adaptation to a swimming
-mode of life. This order probably also originated out of the Semi-apes,
-with which it is even at present closely allied, through the flying
-lemurs (Galeopithecus). Of the two orders of flying animals, the
-insect-eating forms, or _flying mice_ (Nycterides), probably developed
-out of those eating fruits, or _flying foxes_ (Pterocynes); for the
-latter are, in many ways, more closely allied to Semi-apes than are the
-former.
-
-We have now still to discuss the genuine Apes (Simiae) as the last order
-of Mammals; but as, according to the zoological system, the human race
-belongs to this order, and as it undoubtedly developed historically out
-of a branch of this order, we shall devote a special chapter to a more
-careful examination of its pedigree and history.
-
-
-
-
-CHAPTER XXII.
-
-ORIGIN AND PEDIGREE OF MAN.
-
-
-  The Application of the Theory of Descent to Man.--Its Immense
-  Importance and Logical Necessity.--Man's Position in the Natural
-  System of Animals, among Disco-placental Animals.--Incorrect
-  Separation of the Bimana and Quadrumana.--Correct Separation of
-  Semi-apes from Apes.--Man's Position in the Order of
-  Apes.--Narrow-nosed Apes (of the Old World) and Flat-nosed Apes
-  (of America).--Difference of the two Groups.--Origin of Man from
-  Narrow-nosed Apes.--Human Apes, or Anthropoides.--African Human
-  Apes (Gorilla and Chimpanzee).--Asiatic Human Apes (Orang and
-  Gibbon).--Comparison between the different Human Apes and the
-  different Races of Men.--Survey of the Series of the Progenitors
-  of Man.--Invertebrate Progenitors (Prochordata) and Vertebrate
-  Progenitors.
-
-
-Of all the individual questions answered by the Theory of Descent, of
-all the special inferences drawn from it, there is none of such
-importance as the application of this doctrine to Man himself. As I
-remarked at the beginning of this treatise, the inexorable necessity of
-the strictest logic forces us to draw the special deductive conclusion
-from the general inductive law of the theory, that Man has developed
-gradually, and step by step, out of the lower Vertebrata, and more
-immediately out of Ape-like Mammals. That this doctrine is an
-inseparable part of the Theory of Descent, and hence also of the
-universal Theory of Development in general, is recognized by all
-thoughtful adherents of the theory, as well as by all its opponents who
-reason logically.
-
-But if the doctrine be true, then the recognition of the animal origin
-and pedigree of the human race will necessarily affect more deeply than
-any other progress of the human mind the views we form of all human
-relations, and the aims of all human science. It must sooner or later
-produce a complete revolution in the conception entertained by man of
-the entire universe. I am firmly convinced that in future this immense
-advance in our knowledge will be regarded as the beginning of a new
-period of the development of Mankind. It can only be compared to the
-discovery made by Copernicus, who was the first who ventured distinctly
-to express the opinion, that it was not the sun which moved round the
-earth, but the earth round the sun. Just as the _geocentric conception_
-of the universe--namely, the false opinion that the earth was the centre
-of the universe, and that all its other portions revolved round the
-earth--was overthrown by the system of the universe established by
-Copernicus and his followers, so the _anthropocentric conception_ of the
-universe--the vain delusion that Man is the centre of terrestrial
-nature, and that its whole aim is merely to serve him--is overthrown by
-the application (attempted long since by Lamarck) of the theory of
-descent to Man. As Copernicus' system of the universe was mechanically
-established by Newton's theory of gravitation, we see Lamarck's theory
-of descent attain its causal establishment by Darwin's theory of
-selection. This comparison, which is very interesting in many respects,
-I have discussed in detail elsewhere.
-
-In order to carry out this extremely important application of the Theory
-of Descent to man, with the necessary impartiality and objectivity, I
-must above all beg the reader (at least for a short time) to lay aside
-all traditional and customary ideas on the "Creation of Man," and to
-divest himself of the deep-rooted prejudices concerning it, which are
-implanted in the mind in earliest youth. If he fail to do this, he
-cannot objectively estimate the weight of the scientific arguments which
-I shall bring forward in favour of the animal derivation of Man, that
-is, of his origin out of Ape-like Mammals. We cannot here do better than
-imagine ourselves with Huxley to be the inhabitants of another planet,
-who, taking the opportunity of a scientific journey through the
-universe, have arrived upon the earth and have there met with a peculiar
-two-legged mammal called Man, diffused over the whole earth in great
-numbers. In order to examine him zoologically, we should pack a number
-of the individuals of different ages and from different lands (as we
-should do with the other animals collected on the earth) into large
-vessels filled with spirits of wine, and on our return to our own planet
-we should commence the comparative anatomy of all these terrestrial
-animals quite objectively. As we should have no personal interest in
-Man, in a creature so entirely different from ourselves, we should
-examine and criticise him as impartially and objectively as we should
-the other terrestrial animals. In doing this we should, of course, in
-the first place refrain from all conjectures and speculations on the
-nature of his soul, or on the spiritual side of his nature, as it is
-usually called. We should occupy ourselves solely with his bodily
-structure, and with that natural conception of it which is offered by
-the history of his individual development.
-
-It is evident that in order correctly to determine Man's position among
-the other terrestrial organisms we must, in the first place, follow the
-guidance of the natural system. We must endeavour to determine the
-position which belongs to Man in the natural system of animals as
-accurately and distinctly as possible. We shall then, if in fact the
-theory of descent be correct, be able from his position in the system to
-determine the real primary relationship, and the degree of consanguinity
-connecting Man with the animals most like him. The hypothetical pedigree
-of the human race will then follow naturally as the final result of this
-anatomical and systematic inquiry.
-
-Now if, by means of comparative anatomy and ontogeny, we seek for man's
-position in that Natural System of animals which formed the subject of
-the last two chapters, the incontrovertible fact will at once present
-itself to us, that man belongs to the tribe, or phylum, of the
-Vertebrata. Every one of the characteristics, which so strikingly
-distinguish all the Vertebrata from all Invertebrata, is possessed by
-him. It has also never been doubted that of all the Vertebrata the
-Mammals are most closely allied to Man, and that he possesses all the
-characteristic features distinguishing them from all other Vertebrata.
-If then we further carefully examine the three different main groups or
-sub-classes of Mammals--the inter-connections of which were discussed in
-our last chapter--there cannot be the slightest doubt that Man belongs
-to the Placentals, and shares with all other Placentals, the important
-characteristics which distinguish them from Marsupials and from
-Cloacals. Finally, of the two main groups of placental Mammals, the
-Deciduata and the Indeciduata, the group of Deciduata doubtless includes
-Man. For the human embryo is developed with a genuine decidua, and is
-thus absolutely distinguished from all the Indeciduata. Among the
-Deciduata we distinguish two legions, the Zonoplacentalia, with
-girdle-shaped placenta (Beasts of Prey and Pseudo-hoofed animals), and
-the Discoplacentalia, with disc-shaped placenta (all the remaining
-Deciduata). Man possesses a disc-shaped placenta, like all
-Discoplacentalia; and thus our next question must be, What is man's
-position in this group?
-
-In the last chapter we distinguished the following five orders of
-Discoplacentalia: (1) Semi-apes; (2) Rodents; (3) Insectivora; (4) Bats;
-(5) Apes. The last of these five orders, that of Apes, is, as every one
-knows, in every bodily feature far more closely allied to Man than the
-four others. Hence the only remaining question now is, whether, in the
-system of animals, Man is to be directly classed in the order of genuine
-Apes, or whether he is to be considered as the representative of a
-special sixth order of Discoplacentalia, allied to, but more advanced
-than, that of the Apes.
-
-Linnaeus in his system classed Man in the same order with genuine Apes,
-Semi-apes, and Bats, which he called _Primates_; that is, lords, as it
-were the highest dignitaries of the animal kingdom. But Blumenbach, of
-Goettingen, separated Man as a special order, under the name of _Bimana_,
-or two-handed, and contrasted him with the Apes and Semi-apes under the
-name of _Quadrumana_, or four-handed. This classification was also
-adopted by Cuvier and, consequently, by most subsequent zoologists. It
-was not until 1863 that Huxley, in his excellent work, the "Evidence as
-to Man's Place in Nature,"(26) showed that this classification was based
-upon erroneous ideas, and that the so-called "four-handed" Apes and
-Semi-apes are "two-handed" as much as man is himself. The difference
-between the foot and hand does not consist in the _physiological_
-peculiarity that the first digit or thumb is opposable to the four other
-digits or fingers in the hand, and is not so in the foot, for there are
-wild tribes of men who can oppose the first or large toe to the other
-four, just as if it were a thumb. They can therefore use their "grasping
-foot" as well as a so-called "hinder hand," like Apes. The Chinese
-boatmen row with this hinder hand, the Bengal workmen weave with it. The
-Negro, in whom the big toe is especially strong and freely moveable,
-when climbing seizes hold of the branches of the trees with it, just
-like the "four-handed" Apes. Nay, even the newly born children of the
-most highly developed races of men, during the first months of their
-life, grasp as easily with the "hinder hand" as with the "fore hand,"
-and hold a spoon placed in its clutch as firmly with their big toe as
-with the thumb! On the other hand, among the higher Apes, especially the
-gorilla, hand and foot are differentiated as in man. (Compare Plate IV.)
-
-The essential difference between hand and foot is therefore not
-physiological, but _morphological_, and is determined by the
-characteristic structure of the bony skeleton and of the muscles
-attached to it. The ankle-bones differ from the wrist-bones in
-arrangement, and the foot possesses three special muscles not existing
-in the hand (a short flexor muscle, a short extensor muscle, and a long
-fibular muscle). In all these respects, Apes and Semi-apes entirely
-agree with man, and hence it was quite erroneous to separate him from
-them as a special order on account of the stronger differentiation of
-his hand and foot. It is the same also with all the other structural
-features by means of which it was attempted to distinguish Man from
-Apes; for example, the relative length of the limbs, the structure of
-the skull, of the brain, etc. In all these respects, without exception,
-the differences between Man and the higher Apes are less than the
-corresponding differences between the higher and the lower Apes. Hence
-Huxley, for reasons based on the most careful and most accurate
-anatomical comparisons, arrives at the extremely important
-conclusion--"Thus, whatever system of organs be studied, the comparison
-of their modifications in the Ape series leads to one and the same
-result, that the structural differences which separate Man from the
-Gorilla and Chimpanzee are not so great as those which separate the
-Gorilla from the lower Apes." In accordance with this, Huxley, strictly
-following the demands of logic, classes Man, Apes, and Semi-apes in a
-single order, _Primates_, and divides it into the following seven
-families, which are of almost equal systematic value: (1) Anthropini
-(Man); (2) Catarrhini (genuine Apes of the Old World); (3) Platyrrhini
-(genuine American Apes); (4) Arctopitheci (American clawed Apes); (5)
-Lemurini (short-footed and long-footed Semi-apes, p. 255); (6)
-Chiromyini (p. 256); (7) Galeopithecini (Flying Lemurs, p. 256).
-
-
-SYSTEMATIC SURVEY
-
-_Of the Families and Genera of Apes._
-
-
-  -----------------+------------------------+---------------------+------------------
-    _Sections_     |      _Families_        |      _Genera_       | _Systematic Name_
-       _of_        |         _of_           |        _of_         |       _of_
-      _Apes._      |        _Apes._         |       _Apes._       |  _the Genera._
-  -----------------+------------------------+---------------------+------------------
-  I. APES OF THE NEW WORLD (+Hesperopitheci+), OR FLAT-NOSED APES (+Platyrrhini+).
-  -----------------------------------------------------------------------------------
-  A. =Platyrrhini=  {  I. Silky apes         {  1. Brush ape        1. Midas
-    =with claws=    {    _Hapalida_          {  2. Lion ape         2. Jacchus
-                    {
-  +Arctopitheci+    {
-
-                    {  II. Flat-nosed,       {  3. Squirrel ape     3. Chrysothrix
-                    { without prehensile     {  4. Leaping ape      4. Callithrix
-  B. =Platyrrhini=  {       tail             {  5. Nocturnal ape    5. Nyctipithecus
-    =with blunt=    {    _Aphyocerca_        {  6. Tail ape         6. Pithecia
-       =nails=      {
-                    {  III. Flat-nosed,      {  7. Rolling ape      7. Cebus
-  +Dysmopitheci+    {  with prehensile       {  8. Climbing ape     8. Ateles
-                    {      tail              {  9. Woolly ape       9. Lagothrix
-                    {  _Labidocerca_         { 10. Howling ape     10. Mycetes
-  ----------------------------------------------------------------------------------
-  II. APES OF THE OLD WORLD (+Heopitheci+), OR NARROW-NOSED APES (+Catarrhini+).
-  ----------------------------------------------------------------------------------
-                    { IV. Tailed Catarrhini, {
-                    {          with          { 11. Pavian          11. Cynocephalus
-  C. =Tailed=       {     cheek-pouches      { 12. Macaque         12. Innus
-  =Catarrhini=      {      _Ascoparea_       { 13. Sea cat         13. Cercopithecus
-                    {
-  +Menocerca+       { V. Tailed Catarrhini,  {
-                    {        without         { 14. Holy ape        14. Semnopithecus
-                    {     cheek-pouches      { 15. Short ape       15. Colobus
-                    {       _Anasca_         { 16. Nose ape        16. Nasalis
-
-                    {                        { 17. Gibbon          17. Hylobates
-                    {  VI. Human apes        { 18. Orang-Outan     18. Satyrus
-  D. =Tailless=     {   _Anthropoides_       { 19. Chimpanzee      19. Engeco
-  =Catarrhini=      {                        { 20. Gorilla         20. Gorilla
-                    {
-  +Lipocerca+       {     VII. Men           { 21. Ape-like man,   21. Pithecanthropus
-                    {      _Erecti_          { or speechless man         (Alalus)
-                    {    (_Anthropi_)        { 22. Talking man     22. Homo
-
-             ----------------------------------------------------------------
-
-                                       Straight-haired men
-                                          _Lissotrichi_
-                                                |
-             Woolly-haired men                  |
-               _Ulotrichi_                      |
-                    |                           |
-                    |                           |
-                    \-------------v-------------/
-                     Speechless men (_Alali_), or
-                    Ape-like men (_Pithecanthropi_)
-                                  |
-                       Gorilla    |
-                      _Gorilla_   |     Orang
-        Chimpanzee        |       |   _Satyrus_
-        _Engeco_          |       |       |     Gibbon
-            |             |       |       |   _Hylobates_
-            |             |       |       |        |
-            \------v------/       |       |        |
-                African           \-------v--------/
-              Man-like Apes            Asiatic
-                   |                Man-like Apes
-                   |                      |
-                   \----------v-----------/
-                        =Man-like Apes=                    Nose apes
-                        +Anthropoides+                   _Nasalis_
-                              |                              |
-    Silk apes                 |             Tall apes        |
-  _Arctopitheci_              |           _Semnopithecus_    |
-        |        Clutch-tails |                 |            |
-        |       _Labidocerca_ |                 |            |
-        |             |       |                 \-v----------/
-        |             |       |     Sea cat       |       Pavian
-        \-----v-------/       | _Cercopithecus_   |    _Cynocephalus_
-           Flap-tails         |       |           |         |
-          _Aphyocerca_        |       |           |         |
-                              \--------------v--------------/
-        =Flat-nosed Apes=           Tailed Narrow-nosed apes
-        +Platyrrhini+              _Catarrhina menocerca_
-              |                        =Narrow-nosed=
-              |                        +Catarrhini+
-              |                              |
-              |                              |
-              \--------------v---------------/
-                           =Apes=
-                          +Simiae+
-                             |
-                             |
-                         Semi-apes
-                         _Prosimiae_
-
-
-If we wish to arrive at a natural system, and consequently at the
-pedigree of the Primates, we must go a step further still, and entirely
-separate the Semi-apes, or Prosimiae, (Huxley's last three families),
-from Genuine Apes, or Simiae (the first four families). For, as I have
-already shown in my General Morphology, and explained in the last
-chapter, the Semi-apes differ in many and important respects from
-Genuine Apes, and in their individual forms are more closely allied to
-the various other orders of Discoplacentalia. Hence the Semi-apes must
-probably be considered as the remnants of the common primary group, out
-of which the other orders of Discoplacentalia, and, it may be, all
-Deciduata, have developed as two diverging branches. (Gen. Morph. ii.
-pp. 148 and 153.) But man cannot be separated from the order of Genuine
-Apes, or Simiae, as he is in every respect more closely allied to the
-higher Genuine Apes than the latter are to the lower Genuine Apes.
-
-_Genuine Apes_ (Simiae) are universally divided into two perfectly
-natural groups, namely, the Apes of the New World, or American Apes, and
-the Apes of the Old World, which are indigenous to Asia and Africa, and
-which formerly also existed in Europe. These two classes differ
-principally in the formation of the nose, and they have been named
-accordingly. American Apes have flat noses, so that the nostrils are in
-front, not below; hence they are called _Flat Noses_ (Platyrrhini). On
-the other hand, the Apes of the Old World have a narrow cartilaginous
-bridge, and the nostrils turned downwards, as in man; they are,
-therefore, called _Narrow Noses_ (Catarrhini). Further, the jaw, which
-plays an important part in the classification of Mammals, is essentially
-distinct in these two groups. All Catarrhinae, or Apes of the Old World,
-have exactly the same jaws as Man, namely, in each jaw four incisors
-above and below, then on each side a canine tooth and five cheek teeth,
-of which two are pre-molars and three molars, altogether thirty-two
-teeth. But all Apes of the New World, all Platyrrhini, have four more
-cheek teeth, namely, three pre-molars and three molars on each side,
-above and below: they consequently possess thirty-six teeth. Only one
-small group forms an exception to this rule, namely, the _Arctopitheci_,
-or _Clawed Apes_, in whom the third molar has degenerated, and they
-accordingly have on each half of their jaw three pre-molars and two
-molars. They also differ from the other Platyrrhini by having claws on
-the fingers of their hands and the toes of their feet, not nails like
-Man and the other Apes. This small group of South American Apes, which
-includes among others the well-known pretty little Midas-monkey and the
-Jacchus, must probably be considered only as a peculiarly developed
-lateral branch of the Platyrrhini.
-
-Now, if we ask what evidence can be drawn, as to the pedigree of Apes,
-from the above facts, we must conclude that all the Apes of the New
-World have developed out of one tribe, for they all possess the
-characteristic jaw and the nasal formation of the Platyrrhini. In like
-manner it follows that all the Apes of the Old World must be derived
-from one and the same common primary form, which possessed the same
-formation of nose and jaw as all the still living Catarrhini. Further,
-it can scarcely be doubted that the Apes of the New World, taken as an
-entire tribe, are either derived from those of the Old World, or (to
-express it more vaguely and cautiously) both are diverging branches of
-one and the same tribe of Apes. We also arrive at the exceedingly
-important conclusion--which is of the utmost significance in regard to
-Man's distribution on the earth's surface--that Man _has developed out
-of the Catarrhini_. For we cannot discover a zoological character
-distinguishing him in a higher degree from the allied Apes of the Old
-World than that in which the most divergent forms of this group are
-distinguished from one another. This is the important result of Huxley's
-careful anatomical examination of the question, and it cannot be too
-highly estimated. The anatomical differences between Man and the most
-human-like Catarrhini (Orang, Gorilla, Chimpanzee) are in every respect
-less than the anatomical differences between the latter and the lowest
-stages of Catarrhini, more especially the Dog-like Baboon. This
-exceedingly important conclusion is the result of an impartial
-anatomical comparison of the different forms of Catarrhini.
-
-If, therefore, we recognise the natural system of animals as the guide
-to our speculations, and establish upon it our pedigree, we must
-necessarily come to the conclusion that _the human race is a small
-branch of the group of Catarrhini, and has developed out of long since
-extinct Apes of this group in the Old World_. Some adherents of the
-Theory of Descent have thought that the American races of Men have
-developed, independently of those of the Old World, out of American
-Apes. I consider this hypothesis to be quite erroneous, for the complete
-agreement of all mankind with the Catarrhini, in regard to the
-characteristic formation of the nose and jaws, distinctly proves that
-they are of the same origin, and that they developed out of a common
-root after the Platyrrhini, or American Apes, had already branched off
-from them. The primaeval inhabitants of America, as is proved by numerous
-ethnographical facts, immigrated from Asia, and partly perhaps from
-Polynesia (or even from Europe).
-
-There still exist great difficulties in establishing an accurate
-pedigree of the Human Race; this only can we further assert, that the
-nearest progenitors of man were tail-less Catarrhini (Lipocerca),
-resembling the still living Man-like Apes. These evidently developed at
-a late period out of tailed Catarrhini (Menocerca), the original form of
-Ape. Of those tail-less Catarrhini, which are now frequently called
-Man-like Apes, or Anthropoides, there still exist four different genera
-containing about a dozen different species.
-
-The largest Man-like Ape is the famous _Gorilla_ (called Gorilla engena,
-or Pongo gorilla), which is indigenous to the tropics of western Africa,
-and was first discovered by the missionary, Dr. Savage, in 1847, on the
-banks of the river Gaboon. Its nearest relative is the _Chimpanzee_
-(Engeco troglodytes, or Pongo troglodytes), also indigenous to western
-Africa, but considerably smaller than the Gorilla, which surpasses man
-in size and strength. The third of the three large Man-like Apes is the
-_Orang_, or _Orang Outang_, indigenous to Borneo and the other Sunda
-Islands, of which two kindred species have recently been distinguished,
-namely, the large Orang (Satyrus orang, or Pithecus satyrus) and the
-small Orang (Satyrus morio, or Pithecus morio). Lastly, there still
-exists in southern Asia the genus _Gibbon_ (Hylobates), of which from
-four to eight different species are distinguished. They are considerably
-smaller than the three first-named Anthropoides, and in most
-characteristics differ more from Man.
-
-The tail-less Man-like Apes--especially since we have become more
-intimately acquainted with the Gorilla, and its connection with Man by
-the application of the Theory of Descent--have excited such universal
-interest, and called forth such a flood of writings, that there is no
-occasion for me here to enter into any detail about them. The reader
-will find their relations to Man fully discussed in the excellent works
-of Huxley,(26) Carl Vogt,(27) Buechner,(43) and Rolle.(28) I shall
-therefore confine myself to stating the most important general
-conclusion resulting from their thorough comparison with Man, namely,
-that each one of the four Man-like Apes stands nearer to Man in one or
-several respects than the rest, but that no one of them can in every
-respect be called absolutely the most like Man. The Orang stands nearest
-to Man in regard to the formation of the brain, the Chimpanzee in
-important characteristics in the formation of the skull, the Gorilla in
-the development of the feet and hands, and, lastly, the Gibbon in the
-formation of the thorax.
-
-Thus, from a careful examination of the comparative anatomy of the
-Anthropoides, we obtain a similar result to that obtained by Weisbach,
-from a statistical classification and a thoughtful comparison of the
-very numerous and careful measurements which Scherzer and Schwarz made
-of the different races of Men during their voyage in the Austrian
-frigate _Novara_ round the earth. Weisbach comprises the final result of
-his investigations in the following words: "_The ape-like
-characteristics of Man_ are by no means concentrated in one or another
-race, but are distributed in particular parts of the body, among the
-different races, in such a manner that each is endowed with some
-heirloom of this relationship--one race more so, another less, and even
-we Europeans cannot claim to be entirely free from evidences of this
-relationship."[5]
-
-I must here also point out, what in fact is self-evident, that not one
-of all the still living Apes, and consequently not one of the so-called
-Man-like Apes, can be the progenitor of the Human Race. This opinion, in
-fact, has never been maintained by thoughtful adherents of the Theory of
-Descent, but it has been assigned to them by their thoughtless
-opponents. The Ape-like progenitors of the Human Race are long since
-extinct. We may possibly still find their fossil bones in the tertiary
-rocks of southern Asia or Africa. In any case they will, in the
-zoological system, have to be classed in the group of _tail-less
-Narrow-nosed Apes_ (Catarrhini Lipocerci, or Anthropoides).
-
-The genealogical hypotheses, to which we have thus far been led by the
-application of the Theory of Descent to Man, present themselves to every
-clearly and logically reasoning person as the direct results from the
-facts of comparative anatomy, ontogeny, and palaeontology. Of course our
-phylogeny can indicate only in a very general way the outlines of the
-human pedigree. Phylogeny is the more in danger of becoming erroneous
-the more rigorously it is applied in detail to special animal forms
-known to us. However, we can, even now, with approximate certainty
-distinguish at least the following twenty-two stages of the ancestors of
-Man. Fourteen of these stages belong to the Vertebrata, and eight to the
-Invertebrate ancestors of Man (Prochordata.)
-
-
-THE CHAIN OF THE ANIMAL ANCESTORS, OR THE SERIES OF THE PROGENITORS, OF
-MAN.
-
-(Comp. Ch. XX., XXI.; Plate XIV. and p. 22.)
-
-FIRST HALF OF THE SERIES OF THE ANCESTORS OF MAN.
-
-INVERTEBRATE ANCESTORS OF MAN (Prochordata).
-
-FIRST STAGE: +Monera+.
-
-The most ancient ancestors of Man, as of all other organisms, were
-living creatures of the simplest kind imaginable, _organisms without
-organs_, like the still living Monera. They consisted of simple,
-homogeneous, structureless and formless little lumps of mucous or
-albuminous matter (protoplasm), like the still living Protamoeba
-primitiva. (Compare vol. i. p. 186, Fig. 1.) The _form value_ of these
-most ancient ancestors of man was not even equal to that of a cell, but
-merely that of a _cytod_ (compare vol. i. p. 347); for, as in the case
-of all Monera, the little lump of protoplasm did not as yet possess a
-cell-kernel. The first of these Monera _originated_ in the beginning of
-the Laurentian period by _spontaneous generation_, or archigony, out of
-so-called "inorganic combinations," namely, out of simple combinations
-of carbon, oxygen, hydrogen, and nitrogen. The assumption of this
-spontaneous generation, that is, of a mechanical origin of the first
-organisms from inorganic matter, has been proved in our thirteenth
-chapter to be a necessary hypothesis. (Compare vol. i. p. 338.) A
-direct _proof_ of the earlier existence of this most ancient ancestral
-stage, based upon the fundamental law of biogeny, is possibly still
-furnished by the circumstance that, according to the assertions of many
-investigators, in the beginning of the development of the egg, the
-cell-kernel, or nucleus, disappears, and the egg-cell thus relapses to
-the lower stage of the cytod (Monerula, p. 124; _relapse_ of the
-nucleated plastid into a non-nucleated condition). The assumption of
-this first stage is necessary for most important general reasons.
-
-
-SECOND STAGE: +Amoebae+.
-
-The second ancestral stage of Man, as of all the higher animals and
-plants, is formed by _a simple cell_, that is, a little piece of
-protoplasm enclosing a kernel. There still exist large numbers of
-similar "single-celled organisms." Among them the common, simple Amoebae
-(vol. i. p. 188, Fig. 2) cannot have been essentially different from
-these progenitors. The _form value_ of every Amoeba is essentially the
-same as that still possessed by the egg of Man, and by the egg of all
-other animals. (Vol. i. p. 189, Fig. 3.) The naked egg-cells of Sponges,
-which creep about exactly like Amoebae, cannot be distinguished from
-them. The egg-cell of Man, which like that of most other animals is
-surrounded by a membrane, resembles an enclosed Amoeba. The first
-single-celled animals of this kind arose out of Monera by the
-differentiation of the inner kernel and the external protoplasm; they
-lived in the earlier Primordial period. An irrefutable proof that such
-single-celled primaeval animals really existed as the direct ancestors of
-Man, is furnished according to the fundamental law of biogeny (vol. i.
-p. 309) by the fact that the human egg is nothing more than a simple
-cell. (Compare p. 124.)
-
-
-THIRD STAGE: +Synamoebae+.
-
-In order to form an approximate conception of the organisation of those
-ancestors of Man which first developed out of the single-celled Primaeval
-animals, it is necessary to trace the changes undergone by the human egg
-in the beginning of its individual development. It is just here that
-ontogeny guides us with the greatest certainty on to the track of
-phylogeny. We have already seen that the egg of Man (in the same way as
-that of all other Mammals), after fructification has taken place, falls
-by self-division into a mass of simple and equi-formal Amoeba-like cells
-(vol. i. p. 190, Fig. 4 _D_). All these divided globules are at first
-exactly like one another, naked cells containing a kernel, but without
-covering; in many animals they show movements like those of the Amoebae.
-This ontogenetic stage of development which we called Morula (p. 125),
-on account of its mulberry shape, is _a certain proof_ that in the early
-primordial period there existed ancestors of man which possessed the
-_form value_ of a mass of homogeneous, loosely connected cells. They may
-be called a _community of Amoebae_ (Synamoebae). (Compare p. 127.) They
-_originated_ out of the single-celled Primaeval animals of the second
-stage by repeated self-division and by the permanent union of the
-products of this division.
-
-
-FOURTH STAGE: +Ciliated Larva (Planaeada)+.
-
-In the course of the ontogenesis of most of the lower animals, and also
-in that of the lowest Vertebrate animals, the Lanceolate Animals, or
-Amphioxus, there first develops out of the Morula (Frontispiece, Fig. 3)
-a ciliated larva (planula). Those cells, lying on the surface of the
-homogeneous mass of cells, extend hair-like processes, or fringes of
-hairs, which by striking against the water keep the whole body rotating.
-The round many-celled body thus becomes differentiated, in that the
-external cells covered with cilia differ from the non-ciliated internal
-cells (Frontispiece, Fig. 4). In Man and in all other Vertebrate animals
-(with the exception of the Amphioxus), as well as in all Arthropoda,
-this stage of the ciliated larva has been lost, in the course of time,
-by abbreviated inheritance. There must, however, have existed ancestors
-of Man in the early Primordial period which possessed the form value of
-these ciliated larvae (Planaea, p. 125). A certain proof of this is
-furnished by the Amphioxus, which is on the one hand related by blood to
-Man, but on the other has retained down to the present day the stage of
-the planula.
-
-
-FIFTH STAGE: +Primaeval Stomach Animals (Gastraeada)+.
-
-In the course of the individual development of Amphioxus, as well as in
-the most different lower animals, there first arises out of the planula
-the extremely important form of larva which we have named _stomach
-larva_, or _gastrula_ (p. 126; Frontispiece, Fig. 5, 6). According to
-the fundamental law of biogeny this gastrula proves the former existence
-of an independent form of primaeval animal of the same structure, and
-this we have named primaeval stomach animal, or Gastraea (pp. 127, 128).
-These Gastraeada must have existed during the older Primordial period,
-and they must have also included the ancestors of man. A _certain
-proof_ of this is furnished by the Amphioxus, which in spite of its
-blood relationship to Man still passes through the stage of the gastrula
-with a simple intestine and a double intestinal wall. (Compare Plate X.
-Fig. _B 4_.)
-
-
-SIXTH STAGE: +Gliding Worms (Turbellaria)+.
-
-The human ancestors of the sixth stage which originated out of the
-Gastraeada of the fifth stage, were low worms, which, of all the forms of
-worms known to us, were most closely allied to the Gliding Worms, or
-Turbellaria, or at least upon the whole possessed their form value. Like
-the Turbellaria of the present day, the whole surface of their body was
-covered with cilia, and they possessed a simple body of an oval shape,
-entirely without appendages. These acoelomatous worms did not as yet
-possess a true body-cavity (coelom) nor blood. They _originated_ in the
-early primordial period out of the Gastraeada, by the formation of a
-middle germ-layer, or muscular layer, and also by the further
-differentiation of the internal parts into various organs; more
-especially the first formation of a nervous system, the simplest organs
-of sense, the simplest organs for secretion (kidneys) and generation
-(sexual organs). The proof that human ancestors existed of a similar
-formation, is to be looked for in the circumstance that comparative
-anatomy and ontogeny point to the lower acoelomatous Worms as the common
-primary form, not merely of all higher Worms, but also of the four
-higher tribes of animals. Now, of all the animals known to us, the
-Turbellaria, which possess neither a body-cavity nor blood, are most
-closely allied to these primaeval acoelomatous Primary Worms.
-
-
-SEVENTH STAGE: +Soft Worms (Scolecida)+.
-
-Between the Turbellaria of the preceding stage and the Sack Worms of the
-next stage, we must necessarily assume at least one connecting
-intermediate stage. For the Tunicata, which of all known animals stand
-nearest to the eighth stage, and the Turbellaria which most resemble the
-sixth stage, indeed both belong to the lower division of the unsegmented
-Worms; but still these two divisions differ so much from one another in
-their organization, that we must necessarily assume the earlier
-existence of extinct intermediate forms between the two. These
-connecting links, of which no fossil remains exist, owing to the soft
-nature of their bodies, we may comprise as _Soft Worms_, or Scolecida.
-They developed out of the Turbellaria of the sixth stage by forming a
-true body-cavity (a coelom) and blood in their interior. It is difficult
-to say which of the still living Coelomati are nearest akin to these
-extinct Scolecida; it may be the Acorn-worms (Balanoglossus). The proof
-that even the direct ancestors of man belonged to these Scolecida, is
-furnished by the comparative anatomy and the ontogeny of Worms and of
-the Amphioxus. The form value of this stage must moreover have been
-represented by several very different intermediate stages, in the wide
-gap between Turbellaria and Tunicata.
-
-
-EIGHTH STAGE: +Sack Worms (Himatega)+.
-
-Under the name of Sack worms, or Himatega, we here allude in the eighth
-place to those Coelomati, out of which the most ancient skull-less
-Vertebrata were directly developed. Among the Coelomati of the present
-day, the _Ascidians_ are the nearest relatives of these exceedingly
-remarkable Worms, which connect the widely differing classes of
-Invertebrate and Vertebrate animals. That the ancestors of man really
-existed during the primordial period in the form of these Himatega, is
-_distinctly proved_ by the exceedingly remarkable and important
-agreement presented by the ontogeny of the Amphioxus and the Ascidia.
-(Compare Plates XII. and XIII., also pp. 152, 200, etc.) From this fact
-the earlier existence of Sack Worms may be inferred; they of all known
-worms were most closely related to our recent Tunicates, especially to
-the freely swimming young forms or larvae of the simple Sea-squirts
-(Ascidia, Phallusia). They originated out of the worms of the seventh
-stage by the formation of a dorsal nerve-marrow (medulla tube), and by
-the formation of the spinal rod (chorda dorsalis) which lies below it.
-It is just the position of this central spinal rod, or axial skeleton,
-between the dorsal marrow on the dorsal side, and the intestinal canal
-on the ventral side, which is most characteristic of all Vertebrate
-animals, including man, but also of the larvae of the Ascidia. The form
-value of this stage nearly corresponds with that which the larvae of the
-simple Sea-squirts possess at the time when they show the beginning of
-the dorsal marrow and spinal rod. (Plate XII. Fig. _A 5_: compare the
-explanation of these figures in the Appendix.)
-
-
-SECOND HALF OF THE SERIES OF HUMAN ANCESTORS. VERTEBRATE ANIMAL
-ANCESTORS OF MAN (Vertebrata).
-
-NINTH STAGE: +Skull-less Animals (Acrania)+.
-
-The series of human ancestors, which in accordance with their whole
-organisation we have to consider as Vertebrate animals, begins with the
-Skull-less animals, or Acrania, of whose nature the still living
-Lancelet (Amphioxus lanceolatus, Plate XII. _B_, XIII. _B_) gives us a
-faint idea. Since this little animal in its earliest embryonal state
-entirely agrees with the Ascidia, and in its further development shows
-itself to be a true Vertebrate animal, it forms a direct transition from
-the Vertebrata to the Invertebrata. Even if the human ancestors of the
-ninth stage in many respects differed from the Amphioxus--the last
-surviving representative of the Skull-less animals--yet they must have
-resembled it in its most essential characteristics, in the absence of
-head, skull, and brain. Skull-less animals of such structure--out of
-which animals with skulls developed at a later period--lived during the
-primordial period, and originated out of the Himatega of the eighth
-stage by the formation of the metamera, or body segments, as also by the
-further differentiation of all organs, especially the more perfect
-development of the dorsal nerve-marrow and the spinal rod lying below
-it. Probably the separation of the two sexes (gonochorism) also began at
-this stage, whereas all the previously mentioned invertebrate ancestors
-(apart from the 3--4 first neutral stages) exhibited the condition of
-hermaphrodites (hermaphroditism). (Compare vol. i. p. 196.) The _certain
-proof_ of the former existence of these skull-less and brainless
-ancestors of man, is furnished by the comparative anatomy and the
-ontogeny of the Amphioxus and of the Craniota.
-
-
-TENTH STAGE: +Single-nostriled Animals (Monorrhina)+.
-
-Out of the Skull-less ancestors of man there arose in the first place
-animals with skulls, or Craniota, of the most imperfect nature. The
-lowest stage of all still living Craniota is occupied by the class of
-round-mouthed animals, or Cyclostoma, namely, the Hag (Myxinoidea) and
-Lampreys (Petromyzontia). From the internal organization of these
-single-nostriled animals, or Monorrhina, we can form an approximate idea
-of the nature of the human ancestors of the tenth stage. In the former,
-as also in the latter, skull and brain must have been of the simplest
-form, and many important organs, as for example, the swimming bladder,
-the sympathetic nerve, the spleen, the jaw skeleton, and both pairs of
-legs, may probably as yet not have existed. However, the pouch gills and
-the round sucking mouth of the Cyclostoma must probably be looked upon
-as purely adaptive characteristics, which did not exist in the
-corresponding stage of ancestors. The single-nostriled animals
-originated during the primordial period out of the skull-less animals by
-the anterior end of the dorsal marrow developing into the brain, and the
-anterior end of the dorsal chord into the skull. The _certain proof_
-that such single-nostriled and jawless ancestors of man did exist, is
-found in the "comparative anatomy of the Myxinoidea."
-
-
-ELEVENTH STAGE: +Primaeval Fish (Selachii.)+.
-
-Of all known Vertebrate animals, the ancestors of the Primaeval Fish
-probably showed most resemblance to the still living Sharks (Squalacei).
-They _originated_ out of the single-nostriled animals by the division of
-the single nostril into two lateral halves, by the formation of a
-sympathetic nervous system, a jaw skeleton, a swimming bladder, and two
-pairs of legs (breast fins or fore-legs, and ventral fins or hind-legs).
-The internal organisation of this stage may probably, upon the whole,
-have corresponded to the lowest species of Sharks known to us; the
-swimming bladder was however more strongly developed; in the case of the
-latter it exists only as a rudimentary organ. They _lived_ as early as
-the Silurian period, as is proved by the fossil remains of sharks (teeth
-and fin spines) from the Silurian strata. A _certain proof_ that the
-Silurian ancestors of man and of all the other double-nostriled animals
-were nearest akin to the Selachii, is furnished by the comparative
-anatomy of the latter; it shows that the relations of organisation in
-all Amphirrhina can be derived from those of the Selachii.
-
-
-TWELFTH STAGE: +Mud Fish (Dipneusta)+.
-
-Our twelfth ancestral stage is formed by Vertebrate animals which
-probably possessed a remote resemblance to the still living Salamander
-fish (Ceratodus, Protopterus, Lepidosiren, p. 212). They _originated_
-out of the Primaeval fish (probably at the beginning of the palaeolithic,
-or primary period) by adaptation to life on land, and by the
-transformation of the swimming bladder into an air-breathing lung, and
-of the nasal cavity (which now opened into the cavity of the mouth)
-into air passages. The series of the ancestors of man which breathed air
-through lungs began at this stage. Their organisation may probably in
-many respects have agreed with that of the still living Ceratodus and
-Protopterus, but at the same time may have been very different. They
-probably lived at the beginning of the Devonian period. Their existence
-is _proved_ by comparative anatomy, which shows the Dipneusta to be an
-intermediate stage between the Selachii and Amphibia.
-
-
-THIRTEENTH STAGE: +Gilled Amphibians (Sozobranchia)+.
-
-Out of those Mud Fish, which we considered the primary forms of all the
-Vertebrata which breathe through lungs, there developed the class of
-Amphibia as the main line (pp. 205, 216). Here began the five-toed
-formation of the foot (the Pentadactyla), which was thence transmitted
-to the higher Vertebrata, and finally also to Man. The gilled Amphibians
-must be looked upon as our most ancient ancestors of the class of
-Amphibia; besides possessing lungs they retained throughout life regular
-gills, like the still living Proteus and Axolotl (p. 218). They
-_originated_ out of the Dipneusta by the transformation of the paddling
-fins into five-toed legs, and also by the more perfect differentiation
-of various organs, especially of the vertebral column. In any case they
-existed about the middle of the palaeolithic, or primary period, possibly
-even before the Coal period; for fossil Amphibia are found in coal. The
-_proof_ that similar gilled Amphibians were our direct ancestors, is
-given by the comparative anatomy and the ontogeny of Amphibia and
-Mammals.
-
-
-FOURTEENTH STAGE: +Tailed Amphibians (Sozura)+.
-
-Our amphibious ancestors which retained their gills throughout life,
-were replaced at a later period by other Amphibia, which, by
-metamorphosis, lost the gills which they had possessed in early life,
-but retained the tail, as in the case of the salamanders and newts of
-the present day. (Compare p. 218.) They _originated_ out of the gilled
-Amphibians by accustoming themselves in early life to breathe only
-through gills, and later in life only through lungs. They probably
-existed even in the second half of the primary, namely, during the
-Permian period, but possibly even during the Coal period. The _proof_ of
-their existence lies in the fact that tailed Amphibians form a necessary
-intermediate link between the preceding and succeeding stages.
-
-
-FIFTEENTH STAGE: +Primaeval Amniota (Protamnia)+.
-
-The name Protamnion we have given to the primary form of the three
-higher classes of Vertebrate animals, out of which the Proreptilia and
-the Promammalia developed as two diverging branches (p. 222). It
-_originated_ out of unknown tailed Amphibia by the complete loss of the
-gills, by the formation of the amnion, of the cochlea, and of the round
-window in the auditory organ, and of the organs of tears. It probably
-originated in the beginning of the mesolithic or secondary period,
-perhaps even towards the end of the primary, in the Permian period. The
-_certain proof_ that it once existed lies in the comparative anatomy and
-the ontogeny of the Amniota; for all Reptiles, Birds, and Mammals,
-including Man, agree in so many important characteristics that they
-must, with full assurance, be admitted to be the descendants of a
-single common primary form, namely, of the Protamnion.
-
-
-SIXTEENTH STAGE: +Primary Mammals (Promammalia)+.
-
-We now find ourselves more at home with our ancestors. From the
-sixteenth up to the twenty-second stage they all belong to the large and
-well known class of Mammals, the confines of which we ourselves have as
-yet not transgressed. The common, long since extinct and unknown primary
-forms of all Mammalia, which we have named Promammalia, were at all
-events, of all still living animals, of the class most closely related
-to the Beaked animals, or Ornithostoma (Ornithorhynchus, Echidna, p.
-233). They differed from the latter, however, by the teeth present in
-their jaws. The formation of the beak in the Beaked animals of the
-present day must be looked upon as an adaptive characteristic which
-developed at a later period. The Promammalia arose out of the Protamnia
-(probably only at the beginning of the secondary period, namely, in the
-Trias) by various advances in their internal organisation, as also by
-the transformation of the epidermal scales into hairs, and by the
-formation of a mammary gland which furnished milk for the nourishment of
-the young ones. The _certain proof_ that the Promammalia--inasmuch as
-they are the common primary forms of all Mammals--also belong to our
-ancestors, lies in the comparative anatomy and the ontogeny of Mammalia
-and Man.
-
-
-SEVENTEENTH STAGE: +Pouched Animals (Marsupialia)+.
-
-The three sub-classes of Mammalia--as we have already seen--stand in
-such a relation to one another that the Marsupials, both as regards
-their anatomy and their ontogeny and phylogeny, form the direct
-transition from the Monotrema to Placental animals (p. 247).
-Consequently, human ancestors must also have existed among Marsupials.
-They _originated_ out of the Monotrema--which include the primary
-Mammalia, or Promammalia--by the division of the cloaca into the rectum
-and the urogenital sinus, by the formation of a nipple on the mammary
-gland, and by the partial suppression of the clavicles. The oldest
-Marsupials at all events existed as early as the Jura period (perhaps
-even in the Trias); during the Chalk period they passed through a series
-of stages preparing the way for the origin of Placentalia. The certain
-proof of our derivation from Marsupials--nearly akin to the still living
-opossum and kangaroo in their essential inner structure--is furnished by
-the comparative anatomy and the ontogeny of Mammalia.
-
-
-EIGHTEENTH STAGE: +Semi-apes (Prosimiae)+.
-
-The small group of Semi-apes, as we have already seen, is one of the
-most important and most interesting orders of Mammalia. It contains the
-direct primary forms of Genuine Apes, and thus also of Man. Our Semi-ape
-ancestors probably possessed only a very faint external resemblance to
-the still living, short-footed Semi-apes (Brachytarsi), especially the
-Maki, Indri, and Lori (p. 256). They _originated_ (probably at the
-beginning of the Cenolithic, or Tertiary period) out of Marsupials of
-Rat-like appearance by the formation of a placenta, the loss of the
-marsupium and the marsupial bones, and by the higher development of the
-commissures of the brain. The _certain proof_ that Genuine Apes, and
-hence also our own race, are the direct descendants of Semi-apes, is to
-be found in the comparative anatomy and the ontogeny of Placental
-animals.
-
-
-NINETEENTH STAGE: +Tailed Apes (Menocerca)+.
-
-Of the two classes of Genuine Apes which developed out of the Semi-apes,
-it is only the narrow-nosed, or Catarrhini, which are closely related by
-blood to Man. Our older ancestors from this group probably resembled the
-still living Nose-apes and Holy-apes (Semnopithecus), which possess jaws
-and narrow noses like Man, but have a long tail, and their bodies
-densely covered with hair (p. 271). The Tailed Apes with narrow noses
-(Catarrhini Menocerci) _originated_ out of Semi-apes by the
-transformation of the jaw, and by the claws on their toes becoming
-changed into nails; this probably took place as early as the older
-Tertiary period. The _certain proof_ of our derivation from Tailed
-Catarrhini is to be found in the comparative anatomy and the ontogeny of
-Apes and of Man.
-
-
-TWENTIETH STAGE: +Man-like Apes (Anthropoides)+.
-
-Of all still living Apes the large tail-less, narrow-nosed Apes, namely,
-the Orang and Gibbon in Asia, the Gorilla and Chimpanzee in Africa, are
-most nearly akin to Man. It is probable that these Man-like Apes, or
-Anthropoides, originated during the Mid-tertiary period, namely, in the
-Miocene period. They developed out of the Tailed Catarrhini of the
-preceding stage--with which they essentially agree--by the loss of the
-tail, the partial loss of the hairy covering and by the excessive
-development of that portion of the brain just above the facial portion
-of the skull. There do not exist direct human ancestors among the
-Anthropoides of the present day, but they certainly existed among the
-unknown extinct Human Apes of the Miocene period. The _certain proof_ of
-their former existence is furnished by the comparative anatomy of
-Man-like Apes and of Man.
-
-
-TWENTY-FIRST STAGE: +Ape-like Men (Pithecanthropi)+.
-
-Although the preceding ancestral stage is already so nearly akin to
-genuine Men that we scarcely require to assume an intermediate
-connecting stage, still we can look upon the speechless Primaeval Men
-(Alali) as this intermediate link. These Ape-like men, or
-Pithecanthropi, very probably existed towards the end of the Tertiary
-period. They originated out of the Man-like Apes, or Anthropoides, by
-becoming completely habituated to an upright walk, and by the
-corresponding stronger differentiation of both pairs of legs. The fore
-hand of the Anthropoides became the human hand, their hinder hand became
-a foot for walking. Although these Ape-like Men must not merely by the
-external formation of their bodies, but also by their internal mental
-development, have been much more akin to real Men than the Man-like Apes
-could have been, yet they did not possess the real and chief
-characteristic of man, namely, the articulate human language of words,
-the corresponding development of a higher consciousness, and the
-formation of ideas. The _certain proof_ that such Primaeval Men without
-the power of speech, or Ape-like Men, must have preceded men possessing
-speech, is the result arrived at by an inquiring mind from comparative
-philology (from the "comparative anatomy" of language), and especially
-from the history of the development of language in every child ("glottal
-ontogenesis") as well as in every nation ("glottal phylogenesis").
-
-
-TWENTY-SECOND STAGE: +Men (Homines)+.
-
-Genuine Men _developed_ out of the Ape-like Men of the preceding stage
-by the gradual development of the animal language of sounds into a
-connected or articulate language, of words. The development of this
-function, of course, went hand in hand with the development of its
-organs, namely, the higher differentiation of the larynx and the brain.
-The transition from speechless Ape-like Men to Genuine or Talking Men
-probably took place at the beginning of the Quaternary period, namely,
-in the Diluvial period, but possibly even at an earlier date, in the
-more recent Tertiary. As, according to the unanimous opinion of most
-eminent philologists, all human languages are not derived from a common
-primaeval language, we must assume a polyphyletic origin of language, and
-in accordance with this a polyphyletic transition from speechless
-Ape-like Men to Genuine Men.
-
-
-ANCESTRAL SERIES OF THE HUMAN PEDIGREE.
-
-M N = Boundary between the Invertebrate and Vertebrate Ancestors.
-
-
-  ---------------------------------------------------------------------------------------------------
-   _Epochs of the_ |  _Geological Periods_ |         _Animal_          |   _Nearest Living_
-      _Organic_    |       _of the_        |     _Ancestral Stages_    |  _Relatives of the_
-   _History of the_|   _Organic History_   |           _of_            |  _Ancestral Stages._
-       _Earth._    |    _of the Earth._    |          _Man._           |
-  ---------------------------------------------------------------------------------------------------
-                   {                       {  1. Monera                { _Protogenes_
-                   {                       {     (_Monera_)            { _Protamoeba_
-                   {                       {
-                   {                       {  2. Single-celled         { Simple Amoebae
-                   {                       {     Primaeval animals      { (_Automoebae_)
-                   {                       {
-                   {                       {  3. Many-celled           { Communities of
-                   {                       {     Primaeval animals      {   Amoebae
-                   {                       {                           { (_Synamoebae_)
-                   {                       {
-                   {                       {  4. Ciliated planulae      { Planula larvae
-                   {                       {     (_Planaeada_)          {
-           I.      {                       {
-      ARCHILITHIC  { 1. Laurentian Period  {  5. Primaeval Intestinal   { Gastrula larvae
-          OR       {                       {     animals (_Gastraeada_) {
-                   { 2. Cambrian Period    {
-      PRIMORDIAL   {                       {  6. Gliding Worms         { _Rhabdocoela_
-       EPOCH       { 3. Silurian Period    {     (_Turbellaria_)       { _Dendrocoela_
-                   {                       {
-                   {                       {  7. Soft-worms            { ?Between the Sea-squirts
-                   {                       {     (_Scolecida_)         {  and Gliding worms
-                   {                       {
-                   {                       {  8. Sack worms            { Sea-squirts
-                   {                       {     (_Himatega_)          { (_Ascidiae_)
-                   {                       { M.................................................N
-                   {                       {  9. Skull-less            { Lancelets
-                   {                       {     (_Acrania_)           { (_Amphioxi_)
-                   {                       {
-                   {                       { 10. Single-nostriled      { Lampreys
-                   {                       {     (_Monorrhina_)        { (_Petromyzonta_)
-                   {  (Compare p. 22, and  {
-                   {  Plate XIV. and its   { 11. Primaeval fish         { Sharks
-                   {  explanation.)        {     (_Selachii_)          { (_Squalacei_)
-  ---------------------------------------------------------------------------------------------------
-                   { 4. Devonian Period    { 12. Salamander fish       { Mud fish
-         II.       {                       {     (_Dipneusta_)         { (_Protopteri_)
-     PALAEOLITHIC   { 5. Coal Period        {
-         OR        {                       { 13. Gilled Amphibia       { (_Proteus_)
-                   { 6. Permian Period     {     (_Sozobranchia_)      { Axolotl (_Siredon_)
-       PRIMARY     {                       {
-        EPOCH      {                       { 14. Tailed Amphibia       { Water-newts
-                   {                       {     (_Sozura_)            { (_Tritons_)
-  ---------------------------------------------------------------------------------------------------
-                   {                       { 15. Primaeval Amniota      { ?Between the Tailed-Amphibia
-        III.       {                       {     (_Protamnia_)         { and Primary
-     MESOLITHIC    { 7. Trias Period       {                           { mammals
-         OR        {                       {
-                   { 8. Jura Period        { 16. Primary Mammals       { Beaked animals
-      SECONDARY    {                       {     (_Promammalia_)       { (_Monotrema_)
-        EPOCH      { 9. Chalk Period       {
-                   {                       { 17. Pouched animals       { Pouched rats
-                   {                       {     (_Marsupialia_)       { (_Didelphys_)
-  ---------------------------------------------------------------------------------------------------
-                   {                       { 18. Semi-apes             { Lori (_Stenops_)
-                   {                       {     (_Prosimiae_)          { Maki (_Lemur_)
-                   {                       {
-         IV.       {                       { 19. Tailed Narrow-nosed   { Nose apes
-     CENOLITHIC    { 10. Eocene Period     {     Apes                  { Holy apes
-         OR        {                       {
-                   { 11. Miocene Period    { 20. Men-like Apes or      { Gorilla, Chimpanzee,
-      TERTIARY     {                       { Tail-less Narrow-nosed    { Orang,
-       EPOCH       { 12. Pliocene Period   {   Apes                    { Gibbon
-                   {                       {
-                   {                       { 21. Speechless Men or     { Deaf and Dumb,
-                   {                       {     Ape-like Men          { Cretins or
-                   {                       {                           { Microcephali
-  ---------------------------------------------------------------------------------------------------
-         V.        {                       {                           {
-     QUATERNARY    { 13. Diluvial Period   { 22. Talking Men           { Australians and
-       EPOCH       { 14. Alluvial Period   {                           { Papuans
-
-
-
-
-CHAPTER XXIII.
-
-MIGRATION AND DISTRIBUTION OF MANKIND. HUMAN SPECIES AND HUMAN RACES.
-
-
-  Age of the Human Race.--Causes of its Origin.--The Origin of
-  Human Language.--Monophyletic or Single, Polyphyletic or
-  Multiple Origin of the Human Race.--Derivation of Man from many
-  Pairs.--Classification of the Human Races.--System of Twelve
-  Species of Men.--Woolly-haired Men, or Ulotrichis.--Bushy-haired
-  (Papuans, Hottentots).--Fleecy-haired (Caffres,
-  Negroes).--Straight-haired men, or Lissotrichi.--Stiff-haired
-  (Australians, Malays, Mongols, Arctic, and American
-  Tribes).--Curly-haired (Dravidas, Nubians, Midlanders).--Number
-  of Population.--Primaeval Home of Man (South Asia, or
-  Lemuria).--Nature of Primaeval Men.--Number of Primaeval Languages
-  (Monoglottists and Polyglottists).--Divergence and Migration of
-  the Human Race.--Geographical Distribution of the Human Species.
-
-
-The rich treasure of knowledge we possess in the comparative anatomy and
-the history of the development of Vertebrate animals, enables us even
-now to establish the most important outlines of the human pedigree in
-the way we have done in the last chapter. One must, however, not expect
-to be able to survey satisfactorily in every detail the history or
-phylogeny of the human species which will henceforth form the basis of
-Anthropology, and of all other sciences. The complete development of
-this most important science--of which we can only lay the first
-foundation--must remain reserved for the more accurate and extensive
-investigations of a future time. This applies also to those more special
-questions of human phylogeny at which it is desirable before concluding
-to take a cursory glance, namely, the question of the time and place of
-the origin of the human race, as also of the different species and races
-into which it has differentiated.
-
-In the first place, the period of the earth's history, within which the
-slow and gradual transmutation of the most man-like apes into the most
-ape-like men took place, can of course not be determined by years, nor
-even by centuries. This much can, however, with full assurance be
-maintained, for reasons given in the last chapter, that Man is derived
-from Placental animals. Now, as fossil remains of these Placentalia are
-found only in the tertiary rocks, the human race can at the earliest
-have developed only within the Tertiary period out of perfected man-like
-apes. What seems most probable is that this most important process in
-the history of terrestrial creation occurred towards the end of the
-Tertiary period, that is in the Pliocene, perhaps even in the Miocene
-period, but possibly also not until the beginning of the Diluvial
-period. At all events Man, as such, lived in central Europe as early as
-the Diluvial period, contemporaneously with many large, long since
-extinct mammals, especially with the diluvial elephant, or mammoth
-(Elephas primigenius), the woolly-haired rhinoceros (Rhinoceros
-tichorrhinus), the giant deer (Cervus euryceros), the cave bear (Ursus
-spelaeus), the cave hyaena (Hyaena spelaea), the cave lion (Felis spelaeus),
-etc. The results brought to light by recent geology and archaeology as to
-these fossil men and their animal contemporaries of the diluvial period,
-are of the greatest interest. But as a closer examination of them would
-occupy too much of my limited space, I must confine myself here to
-setting forth their great general importance, and refer for particulars
-to the numerous writings which have recently been published on the
-Primaeval History of Man, more especially to the excellent works of
-Charles Lyell,(30) Carl Vogt,(27) Friedrich Rolle,(28) John Lubbock,(44)
-L. Buechner,(43) etc.
-
-The numerous and interesting discoveries presented to us by these
-extensive investigations of late years on the primaeval history of the
-human race, place the important fact (long since probable for many other
-reasons) beyond a doubt, that the human race, as such, has existed for
-more than twenty thousand years. But it is also probable that more than
-a hundred thousand years, perhaps many hundred thousands of years, have
-elapsed since its first appearance; and, in contrast to this, it must
-seem very absurd that our calendars still represent the "Creation of the
-World, according to Calvisius," to have taken place 5821 years ago.
-
-Now, whether we reckon the period during which the human race, as such,
-has existed and diffused itself over the earth, as twenty thousand, a
-hundred thousand, or many hundred thousands of years, the lapse of time
-is in any case immensely small in comparison with the inconceivable
-length of time which was requisite for the gradual development of the
-long chain of human ancestors. This is evident even from the small
-thickness of all Diluvial deposits in comparison with the Tertiary, and
-of these again in comparison with the preceding deposits. (Compare p.
-22.) But the infinitely long series of slowly and gradually developing
-animal forms from the simplest Moneron to the Amphioxus, from this to
-the Primaeval Fish, from the Primaeval Fish to the first Mammal, and
-again, from the latter to Man, also require for their historical
-development a succession of periods probably comprising many thousands
-of millions of years. (Compare vol. i. p. 129.)
-
-Those processes of development which led to the origin of the most
-Ape-like Men out of the most Man-like Apes must be looked for in the two
-adaptational changes which, above all others, are distinctive of Man,
-namely, _upright walk_ and _articulate speech_. These two
-_physiological_ functions necessarily originated together with two
-corresponding _morphological_ transmutations, with which they stand in
-the closest correlation, namely, the _differentiation of the two pairs
-of limbs and the differentiation of the larynx_. The important
-perfecting of these organs and their functions must have necessarily and
-powerfully reacted upon the differentiation of the brain and the mental
-activities dependent upon it, and thus have paved the way for the
-endless career in which Man has since progressively developed, and in
-which he has far outstripped his animal ancestors. (Gen. Morph. ii. p.
-430.)
-
-The first and earliest of these three great processes in the development
-of the human organism probably was the _higher differentiation and the
-perfecting of the extremities_ which was effected by the _habit of an
-upright walk_. By the fore feet more and more exclusively adopting and
-retaining the function of grasping and handling, and the hinder feet
-more and more exclusively the function of standing and walking, there
-was developed that contrast between the hand and foot which is indeed
-not exclusively characteristic of man, but which is much more strongly
-developed in him than in the apes most like men. This differentiation of
-the fore and hinder extremities was, however, not merely most
-advantageous for their own development and perfecting, but it was
-followed at the same time by a whole series of very important changes in
-other parts of the body. The whole vertebral column, and more especially
-the girdle of the pelvis and shoulders, as also the muscles belonging to
-them, thereby experienced those changes which distinguish the human body
-from that of the most man-like apes. These transmutations were probably
-accomplished long before the origin of articulate speech; and the human
-race thus existed for long, with an upright walk and the characteristic
-human form of body connected with it, before the actual development of
-human language, which would have completed the second and the more
-important part of human development. We may therefore distinguish a
-special (21st) stage in the series of our human ancestors, namely,
-Speechless Man (Alalus), or Ape-man (Pithecanthropus), whose body was
-indeed formed exactly like that of Man in all essential characteristics,
-but who did not as yet possess articulate speech.
-
-The origin of _articulate language_, and the _higher differentiation and
-perfecting of the larynx_ connected with it, must be looked upon as only
-a later, and the most important stage in the process of the development
-of Man. It was, doubtless, this process which above all others helped to
-create the deep chasm between man and animal, and which also first
-caused the most important progress in the mental activity and the
-perfecting of the brain connected with it. There indeed exists in very
-many animals a language for communicating sensations, desires, and
-thoughts, partly a language of gestures, partly a language of feeling or
-touch, partly a language of cries or sounds, but a real language of
-words or ideas, a so-called "articulate" language, which by abstraction
-changes sounds into words, and words into sentences, belongs, as far as
-we know, exclusively to Man.
-
-The origin of human language must, more than anything else, have had an
-ennobling and transforming influence upon the mental life of Man, and
-consequently upon his brain. The higher differentiation and perfecting
-of the brain and mental life as its highest function developed in direct
-correlation with its expression by means of speech. Hence, the highest
-authorities in comparative philology justly see in the development of
-human speech the most important process which distinguishes Man from his
-animal ancestors. This has been especially set forth by August
-Schleicher, in his treatise "On the Importance of Speech for the Natural
-History of Man."(34) In this relation we see one of the closest
-connections between comparative zoology and comparative philology; and
-here the theory of development assigns to the latter the task of
-following the origin of language step by step. This task, as interesting
-as it is important, has of late years been successfully undertaken by
-many inquirers, but more especially by Wilhelm Bleek, who has been
-occupied for seventeen years in South Africa with the study of the
-languages of the lowest races of men, and hence has been enabled to
-solve the question. August Schleicher more especially discusses, in
-accordance with the theory of selection, how the various forms of
-speech, like all other organic forms and functions, have developed by
-the process of natural selection, and have divided into many species and
-dialects.
-
-I have no space here to follow the process of the formation of language,
-and must refer in regard to this to the above-mentioned important work
-of Wilhelm Bleek, "On the Origin of Language."(35) But we have still to
-mention one of the most important results of comparative philology,
-which is of the highest importance to the genealogy of the human
-species, that is, that _human language was probably of a multiple, or
-polyphyletic origin_. Human speech, as such, did not develop probably
-until the genus of Speechless or Primaeval Man, or Ape Man, had
-separated into several kinds or species. In each of these human species,
-and perhaps even in the different sub-species and varieties of this
-species, language developed freely and independently of the others. At
-least Schleicher, one of the first authorities on the subject, maintains
-that "even the beginnings of language--in sounds as well as in regard to
-ideas and views which were reflected in sounds, and further, in regard
-to their capability of development--must have been different. For it is
-positively impossible to trace all languages to one and the same
-primaeval language. An impartial investigation rather shows that there
-are as many primaeval languages as there are races."(34) In like manner,
-Friederich Mueller(41) and other eminent linguists assume a free and
-independent origin of the families of languages and their primaeval
-stocks. It is well known, however, that the boundaries of these tribes
-of languages and their ramifications are by no means always the
-boundaries of the different human species, or the so-called "races,"
-distinguished by us on account of their bodily characteristics. This,
-as well as the complicated relations of the mixture of races, and the
-various forms of hybrids, is the great difficulty lying in the way of
-tracing the human pedigree in its individual branches, species, races,
-varieties, etc.
-
-In spite of these great and serious difficulties, we cannot here refrain
-from taking one more cursory glance at the ramification of the human
-pedigree, and at the same time considering, from the point of view of
-the theory of descent, the much discussed question of the monophyletic
-or polyphyletic origin of the human race, and its species or races. As
-is well known, two great parties have for a long time been at war with
-each other upon this question; the _monophylists_ (or monogenists)
-maintain the unity of origin and the blood relationship of all races of
-men. The _polyphylists_ (or polygenists), on the other hand, are of
-opinion that the different races of men are of independent origin.
-According to our previous genealogical investigations we cannot doubt
-that, at least in a _wide sense_, the monophyletic opinion is the right
-one. For even supposing that the transmutation of Man-like Apes into Men
-had taken place several times, yet those Apes themselves would again be
-allied by the one pedigree common to the whole order of Apes. The
-question therefore would always be merely about a nearer or remoter
-degree of blood relationship. In a _narrower sense_, on the other hand,
-the polyphylist's opinion would probably be right, inasmuch as the
-different primaeval languages have developed quite independently of one
-another. Hence, if the origin of an articulate language is considered as
-the real and principal act of humanification, and the species of the
-human race are distinguished according to the roots of their language,
-it might be said that the different races of men had originated,
-independently of one another, by different branches of primaeval,
-speechless men directly springing from apes, and forming their own
-primaeval language. Still they would of course be connected further up or
-lower down at their root, and thus all would finally be derived from a
-common primaeval stock.
-
-While we hold the latter of these convictions, and while we for many
-reasons believe that the different species of speechless primaeval men
-were all derived from a common ape-like human form, we do not of course
-mean to say that _all men are descended from one pair_. This latter
-supposition, which our modern Indo-Germanic culture has taken from the
-Semitic myth of the Mosaic history of creation, is by no means tenable.
-The whole of the celebrated dispute, as to whether the human race is
-descended from a single pair or not, rests upon a completely false way
-of putting the question. It is just as senseless as the dispute as to
-whether all sporting dogs or all race-horses are descended from a single
-pair. We might with equal justice ask whether all Germans or all
-Englishmen are "descended from a single pair," etc. A "first human
-pair," or "a first man," has in fact never existed, any more than there
-ever existed a first pair or a first individual of Englishmen, Germans,
-race-horses, or sporting dogs. The origin of a new species, of course,
-always results from an existing species, by a long chain of many
-different individuals sharing the slow process of transformation.
-Supposing that we had all the different pairs of Human Apes and Ape-like
-Men before us--which belong to the true ancestors of the human race--it
-would even then be quite impossible (without doing so most arbitrarily)
-to call any one of these pairs of ape-like men "the first pair." As
-little can we derive each of the twelve races or species of men, which
-we shall consider directly, from a "first pair."
-
-The difficulties met with in classifying the different races or species
-of men are quite the same as those which we discover in classifying
-animal and vegetable species. In both cases forms apparently quite
-different are connected with one another by a chain of intermediate
-forms of transition. In both cases the dispute as to what is a kind or a
-species, what a race or a variety, can never be determined. Since
-Blumenbach's time, as is well known, it has been thought that mankind
-may be divided into five races or varieties, namely: (1) the Ethiopian,
-or black race (African negro); (2) the Malayan, or brown race (Malays,
-Polynesians, and Australians); (3) the Mongolian, or yellow race (the
-principal inhabitants of Asia and the Esquimaux of North America); (4)
-the Americans, or red race (the aborigines of America); and (5) the
-Caucasian, or white race (Europeans, north Africans, and south-western
-Asiatics). All of these five races of men, according to the Jewish
-legend of creation, are said to have been descended from "a single
-pair"--Adam and Eve,--and in accordance with this are said to be
-varieties of one kind or species. If, however, we compare them without
-prejudice, there can be no doubt that the differences of these five
-races are as great and even greater than the "specific differences" by
-which zoologists and botanists distinguish recognised "good" animal and
-vegetable species ("bonae species"). The excellent palaeontologist
-Quenstedt is right in maintaining that, "if Negroes and Caucasians were
-snails, zoologists would universally agree that they represented two
-very excellent species, which could never have originated from one pair
-by gradual divergence."
-
-The characteristics by which the races of men are gradually
-distinguished are partly taken from the formation of the hair, partly
-from the colour of the skin, and partly from the formation of the skull.
-In regard to the last character, two extremes are distinguished, namely,
-long heads and short heads. In _long-headed men_ (Dolichocephali), whose
-strongest development is found in Negroes and Australians, the skull is
-extended, narrow, and compressed on the right and left. In _short-headed
-men_ (Brachycephali), on the other hand, the skull is compressed in an
-exactly opposite manner, from the front to the back, is short and broad,
-which is especially striking in the case of the Mongolians.
-_Medium-headed men_ (Mesocephali), standing between the two extremes,
-predominate especially among Americans. In every one of these three
-groups we find men with _slanting teeth_ (Prognathi), whose jaws, like
-those of the animal snout, strongly project, and whose front teeth
-therefore slope in front, and men with _straight teeth_ (Orthognathi),
-whose jaws project but little, and whose front teeth stand
-perpendicularly. During the last ten years a great deal of time and
-trouble have been devoted to the careful examination and measurement of
-the forms of skulls, which have, however, not been rewarded by
-corresponding results. For within a single species, as for example
-within the Mediterranean species, the form of the skull may vary so much
-that both extremes are met with in the same species. Much better
-starting-points for the classification of the human species are
-furnished by the nature of the hair and speech, because they are much
-more strictly hereditary than the form of the skull.
-
-Comparative philology seems especially to be becoming an authority in
-this matter. In the latest great work on the races of men, which
-Friederich Mueller has published in his excellent "Ethnography,"(42) he
-justly places language in the fore-ground. Next to it the nature of the
-hair of the head is of great importance; for although it is in itself of
-course only a subordinate morphological character, yet it seems to be
-strictly transmitted within the race. Of the twelve species of men
-distinguished on the following table (p. 308), the four lower species
-are characterised by the woolly nature of the hair of their heads; every
-hair is flattened like a tape, and thus its section is oval. These four
-species of _woolly-haired men_ (Ulotrichi) we may reduce into two
-groups--tuft-haired and fleecy-haired. The hair on the head of
-_tuft-haired men_ (Lophocomi), Papuans and Hottentots, grows in
-unequally divided small tufts. The woolly hair of _fleecy-haired men_
-(Eriocomi), on the other hand, in Caffres and Negroes, grows equally all
-over the skin of the head. All Ulotrichi, or woolly-haired men, have
-slanting teeth and long heads, and the colour of their skin, hair, and
-eyes is always very dark. All are inhabitants of the Southern
-Hemisphere; it is only in Africa that they come north of the equator.
-They are on the whole at a much lower stage of development, and more
-like apes, than most of the Lissotrichi, or straight-haired men. The
-Ulotrichi are incapable of a true inner culture and of a higher mental
-development, even under the favourable conditions of adaptation now
-offered to them in the United States of North America. No woolly-haired
-nation has ever had an important "history."
-
-
-SYSTEMATIC SURVEY
-
-_Of the 12 Species of Men and their 36 Races._
-
-(Compare Plate XV.)
-
-
-  -------------------+--------------------------+----------------------------+-------------
-     _Species._      |         _Races._         |         _Home._            | _Immigrated_
-                     |                          |                            |  _from the_
-  -------------------+--------------------------+----------------------------+-------------
-  { 1. =Papuan=      {  1. Nigritos               Malacca, Philippine          West
-  { +Homo Papua+     {                              Islands
-  {                  {  2. New Guinea men         New Guinea                   West
-  { 2. =Hottentot=   {  3. Melanesians            Melanesia                    North-west
-  {     +Homo+       {  4. Tasmanians             Van Diemen's Land            North-east
-  { +Hottentottus+
-  {                  {  5. Hottentots             The Cape                     North-east
-  {                  {  6. Bushmen                The Cape                     North-east
-
-  { 3. =Kaffre=      {  7. Zulu Kaffres           Eastern South Africa         North
-  { +Homo Cafer+     {  8. Beschuanas             Central South Africa         North-east
-  {                  {  9. Congo Kaffres          Western South Africa         East
-  {
-  { 4. =Negro=       { 10. Tibu negroes           Tibu district                South-east
-  { +Homo Niger+     { 11. Soudan negroes         Soudan                       East
-  {                  { 12. Senegambians           Senegambia                   East
-  {                  { 13. Nigritians             Nigritia                     East
-  .......................................................................................
-
-  { 5. =Australian=  { 14. North Australians      North Australia              North
-  { +H. Australis+   { 15. South Australians      South Australia              North
-  {
-  { 6. =Malay=       { 16. Sundanesians           Sunda Archipelago            West
-  { +Homo Malayus+   { 17. Polynesians            Pacific Archipelago          West
-  {                  { 18. Natives of Madagascar  Madagascar                   East
-  {
-  { 7. =Mongolian=   { 19. Indo-Chinese           Tibet, China                 South
-  {    +Homo+        { 20. Coreo-Japanese         Corea, Japan                 South-west
-  {  +Mongolus+      { 21. Altaians }             Central Asia, North Asia     South
-  {                  { 22. Uralians}              North-western Asia,          South-east
-  {                  {                              Northern Europe,
-  {                  {                              Hungary
-  {
-  { 8. =Arctic Men=  { 23. Hyperboreans           Extreme N.E. of Asia         South-west
-  { +Homo Arcticus+  { 24. Esquimaux              The extreme north of         West
-  {                  {                             America
-  {
-  { 9. =American=    { 25. North Americans        North America                North-west
-  {    +Homo+        { 26. Central Americans      Central America              North
-  { +Americanus+     { 27. South Americans        South America                North
-  {                  { 28. Patagonians            The extreme south of         North
-  {                  {                              South America
-
-  { 10. =Dravidas=   { 29. Deccans                Hindostan                    East?
-  { +Homo Dravida+   { 30. Singalese              Ceylon                       North?
-  {
-  { 11. =Nubian=     { 31. Dongolese              Nubia                        East
-  { +Homo Nuba+      { 32. Fulatians              Fulu-land (Central           East
-  {                  {                              Africa)
-  {
-  { 12.              { 33. Caucasians             Caucasus                     South-east
-  { =Mediterranese=  { 34. Basque                 Extreme north of Spain       South?
-  {    +Homo+        { 35. Semites                Arabia, North Africa, etc.   East
-  { +Mediterraneus+  { 36. Indo-germanic          South-western Asia,          South-east
-  {                  {       tribes                 Europe, etc.
-
-             ----------------------------------------------------------------
-
-                                                          Indo-Germanians
-   9. =Americans=                               Semites          |
-       |                        Magyars            |             |    Caucasians
-       |   Esquimaux               |               |    Basques  |         |
-       |        |                 Fins             |       |     |         |
-       |        |                  |               \---v---/     \----v----/
-       |  Hyperboreans             |                   |              |
-       | 8. =Arctic Men=           |    Samoides       |              |
-       |        |          Tartars |       |           |              |
-       |        |             |    |       |           \-------v-------/
-       \---v----/             |    |       |          12. =Mediterranese=
-           |        Calmucks  |    |       |      Singalese    |
-           | Tungusians |     |    |       |          |        |   Fulatians
-           |      |     |     |    |       |       Deccans     |       |
-           \--------v---------/    \---v---/    10. =Dravidas= |   Dongolese
-                 =Altaians=        =Uralians=         |        | 11. =Nubians=
-                    |                  |              |        |       |
-                    |                  |              |        |       |
-  Japanese          \--------v---------/              \-------v--------/
-      |               =Ural-Altaians=                     +Euplocomi+
-      |         Chinese          |                              |
-  Coreans          |     Siamese |               Madagascars    |
-      |            | Tibet  |    |  Polynesians       |         |
-      |            |   |    |    |        |           |         |        4. =Negroes=
-      |            |   |    |    |        |           |         | 3. =Kaffres=   |
-  =Coreo-Japanese= \---v----/    |        \-----v-----/         |      |         |
-      |          =Indo-Chinese=  |         Sundanesians         |      |         |
-      |               |          |              |               |      \---v-----/
-      |               |          |              |               |       +Eriocomi+
-      |               |          |              |               |          |
-      \-----------v-------------/         6. =Malays=           |          |
-             7. =Mongols=                       |               |          |
-                  |                             |               |          |
-                  |                             |               |          |
-                  \-------v-------------------------------------/          |
-                      =Promalays=                  2. =Hottentots=         |
-                          |               1. =Papuans=     |               |
-                          |   5. =Australians=    |        |               |
-                          |           |           |        |               |
-                          |           |           \----v---/               |
-                          \-----v-----/          +Lophocomi+               |
-                            +Euthycomi+                |                   |
-                                |                      \---------v---------/
-                                |                         =Woolly-haired=
-                         =Straight-haired=                   +Ulotrichi+
-                           +Lissotrichi+                         |
-                                |                                |
-                                |                                |
-                                \--------------v-----------------/
-                                         +Primaeval Men+
-
-
-In the eight higher races of men, which we comprise as _straight-haired_
-(Lissotrichi), the hair of the head is never actually woolly, although
-it is very much frizzled in some individuals. Every separate hair is
-cylindrical (not like a tape), and hence its section is circular (not
-oval).
-
-The eight races of Lissotrichi may likewise be divided into two
-groups--stiff-haired and curly-haired. _Stiff-haired men_ (Euthycomi),
-the hair of whose heads is quite smooth and straight, and not frizzled,
-include Australians, Malays, Mongolians, Arctic tribes, and Americans.
-Curly-haired men, on the other hand, the hair of whose heads is more or
-less curly, and in whom the beard is more developed than in all other
-species, include the Dravidas, Nubians, and Mediterranean races.
-(Compare Plate XV.)
-
-Now, before we venture upon the attempt hypothetically to explain the
-phyletic divergence of mankind, and the genealogical connection of its
-different species, we will premise a short description of the twelve
-named species and of their distribution. In order clearly to survey
-their geographical distribution, we must go back some three or four
-centuries, to the time when the Indian Islands and America were first
-discovered, and when the present great mingling of species, and more
-especially the influx of the Indo-Germanic race, had as yet not made
-great progress. We begin with the lowest stages, with the woolly-haired
-men (Ulotrichi), all of whom are prognathic Dolichocephali.
-
-The _Papuan_ (Homo Papua), of all the still living human species, is
-perhaps most closely related to the original primary form of
-woolly-haired men. This species now inhabits only the large island of
-New Guinea and the Archipelago of Melanesia lying to the east of it
-(Solomon's Islands, New Caledonia, the New Hebrides, etc.). But
-scattered remnants of it are also still found in the interior of the
-peninsula of Malacca, and likewise in many other islands of the large
-Pacific Archipelago; mostly in the inaccessible mountainous parts of the
-interior, and especially in the Philippine Islands. The but lately
-extinct Tasmanians, or the natives of Van Diemen's Land, belonged to
-this group. From these and other circumstances it is clear that the
-Papuans in former times possessed a much larger area of distribution in
-south-eastern Asia. They were driven out by the Malays and forced
-eastwards. The skin of all Papuans is of a black colour, sometimes more
-inclining to brown, sometimes more to blue. Their woolly hair grows in
-tufts, is spirally twisted in screws, and often more than a foot in
-length, so that it forms a strong woolly wig, which stands far out from
-the head. Their face, below the narrow depressed forehead, has a large
-turned-up nose and thick protruding lips. The peculiar form of their
-hair and speech so essentially distinguishes the Papuans from their
-straight-haired neighbours, from the Malays as well as from the
-Australians, that they must be regarded as an entirely distinct species.
-
-Closely related to the Papuans by the tufted growth of hair, but
-geographically widely separated from them, are the _Hottentots_ (Homo
-Hottentottus). They inhabit exclusively the southernmost part of Africa,
-the Cape and the adjacent parts, and have immigrated there from the
-north-east. The Hottentots, like their original kinsmen the Papuans,
-occupied in former times a much larger area (probably the whole of
-Eastern Africa), and are now approaching their extinction. Besides the
-genuine Hottentots--of whom there now exist only the two tribes of the
-Coraca (in the eastern Cape districts) and the Namaca (in the western
-portion of the Cape)--this species also includes the Bushmen (in the
-mountainous interior of the Cape). The woolly hair of all Hottentots
-grows in tufts, like brushes, as in the case of Papuans. Both species
-also agree in the posterior part of the body, in the female sex being
-specially inclined to form a great accumulation of fat (Steatopygia).
-But the skin of Hottentots is much lighter, of a yellowish brown colour.
-Their very flat face is remarkable for its small forehead and nose, and
-large nostrils. The mouth is very broad with big lips, the chin small
-and pointed. Their speech is characterised by several quite peculiar
-guttural sounds.
-
-The next neighbours and kinsmen of Hottentots are _Kaffres_ (Homo
-Cafer). This woolly-haired human species is, however, distinguished,
-like the following one (the genuine Negro), from Hottentots and Papuans
-by the woolly hair not being divided into tufts, but covering the head
-as a thick fleece. The colour of their skin varies through all shades,
-from the yellowish black of the Hottentot to the brown black or pure
-black of the genuine Negro. While in former times the race of Kaffres
-was assigned to a very small area of distribution, and was generally
-looked upon only as a variety of the genuine Negro, this species is now
-considered to include almost the whole of the inhabitants of equatorial
-Africa, from the 20th degree south latitude to the 4th degree north;
-consequently, all South Africans, with the exception of the Hottentots.
-They include especially the inhabitants of the Zulu, Zambesi, and
-Mozambique districts on the east coast, the large human families of the
-Beschuans or Setschuans in the interior, and the Herrero and Congo
-tribes of the west coast. They too, like the Hottentots, have immigrated
-from the north-east. Kaffres, who were usually classed with Negroes,
-differ very essentially from them by the formation of their skull and by
-their speech. Their face is long and narrow, their forehead high, and
-their nose prominent and frequently curved, their lips not so
-protruding, and their chin pointed. The many languages of the different
-tribes of Kaffres can all be derived from an extinct primaeval language,
-namely, from the Bantu language.
-
-The genuine _Negro_ (Homo Niger)--when Kaffres, Hottentots, and Nubians
-are separated from him--at present forms a much less comprehensive human
-species than was formerly supposed. They now only include the Tibus, in
-the eastern parts of the Sahara; the Sudan people, or Sudians, who
-inhabit the south of that large desert; also the inhabitants of the
-Western Coast of Africa, from the mouth of the Senegal in the north, to
-beyond the estuary of the Niger in the south (Senegambians and
-Nigritians). Genuine Negroes are accordingly confined between the
-equator and the Tropic of Capricorn, and only a small portion of the
-Tibu tribe in the east have gone beyond this boundary. The Negro species
-has spread within this zone, coming from the east. The colour of the
-skin of genuine negroes is always more or less of a pure black. Their
-skin is velvety to the touch, and characterised by a peculiar offensive
-exhalation. Although Negroes agree with Kaffres in the formation of the
-woolly hair of the head, yet they differ essentially in the formation of
-their face. Their forehead is flatter and lower, their nose broad and
-thick, not prominent, their lips large and protruding, and their chin
-very short. Genuine Negroes are moreover distinguished by very thin
-calves and very long arms. This species of men must have branched into
-many separate tribes at a very early period, for their numerous and
-entirely distinct languages can in no way be traced to one primaeval
-language.
-
-To the four woolly-haired species of men just discussed, straight-haired
-men (Homines Lissotrichi) stand in strong contrast, as another main
-branch of the genus. Five of the eight species of the latter, as we have
-seen, can be comprised as stiff-haired (Euthycomi) and three as
-curly-haired (Euplocomi). We shall in the first place consider the
-former, which includes the primaeval inhabitants of the greater part of
-Asia and the whole of America.
-
-The lowest stage of all straight-haired men, and on the whole perhaps of
-all the still living human species, is occupied by the _Australian_, or
-_Austral-negro_ (Homo Australis). This species seems to be exclusively
-confined to the large island of Australia; it resembles the genuine
-African Negro by its black or brownish black hair, and the offensive
-smell of the skin, by its very slanting teeth and long-headed form of
-skull, the receding forehead, broad nose, protruding lips, and also by
-the entire absence of calves. On the other hand Australians differ from
-genuine Negroes as well as from their nearest neighbours the Papuans, by
-the much weaker and more delicate structure of their bones, and more
-especially by the formation of the hair of their heads, which is not
-woolly and frizzled, but either quite lank or only slightly curled. The
-very low stage of bodily and mental development of the Australian is
-perhaps not altogether original, but has arisen by degeneration, that
-is, by adaptation to the very unfavourable conditions of existence in
-Australia. They probably immigrated to their present home from the north
-or north-west, as a very early offshoot of the Euthycomi. They are
-probably more closely related to the Dravidas, and hence to the
-Euplocomi, than the other Euthycomi. The very peculiar language of the
-Australians is broken up into numerous small branches, which are grouped
-into a northern and a southern class.
-
-The _Malay_ (Homo Malayus), the brown race of ethnographers, although
-not a large species, is important in regard to its genealogy. An extinct
-south Asiatic human species, very closely related to the Malays of the
-present day, must probably be looked upon as the common primary form of
-this and the following higher human species. We will call this
-hypothetical primary species, Primaeval Malays, or Promalays. The Malays
-of the present day are divided into two widely dispersed races, the
-_Sundanesians_, who inhabit Malacca, the Sunda Islands (Sumatra, Java,
-Borneo, etc.) and the Philippine Islands, and the _Polynesians_, who are
-dispersed over the greater portion of the Pacific Archipelago. The
-northern boundary of their wide tract of distribution is formed on the
-east by the Sandwich Islands (Hawai), and on the west by the Marian
-Islands (Ladrones); the southern boundary on the east is formed by the
-Mangareva Archipelago, and on the west by New Zealand. The inhabitants
-of Madagascar are an especial branch of Sundanesians who have been
-driven to the far west. This wide pelagic distribution of the Malays is
-explained by their partiality for nautical life. Their primaeval home is
-the south-eastern portion of the Asiatic continent, from whence they
-spread to the east and south, and drove the Papuans before them. The
-Malays, in the formation of body, are nearest akin to the Mongols, but
-are also nearly allied to the curly-haired Mediterranese. They are
-generally short-headed, more rarely medium-headed, and very rarely
-long-headed. Their hair is black and stiff, but frequently somewhat
-curled. The colour of their skin is brown, sometimes yellowish, or of a
-cinnamon colour, sometimes reddish or copper brown, more rarely dark
-brown. In regard to the formation of face, Malays in a great measure
-form an intermediate stage between the Mongols and the Mediterranese;
-they can frequently not be distinguished from the latter. Their face is
-generally broad, with prominent nose and thick lips, the opening for
-their eyes not so narrowly cut and slanting as in Mongols. The near
-relationship between all Malays and Polynesians is proved by their
-language, which indeed broke up at an early period into many small
-branches, but still can always be traced to a common and quite peculiar
-primaeval language.
-
-The _Mongol_ (Homo Mongolus) is, next to the Mediterranese, the richest
-in individuals. Among them are all the inhabitants of the Asiatic
-Continent, excepting the Hyperboreans in the north, the few Malays in
-the south-east (Malacca), the Dravidas in Western India, and the
-Mediterranese in the south-west. In Europe this species of men is
-represented by the Fins and Lapps in the north, by the Osmanlis in
-Turkey, and the Magyars in Hungary. The colour of the Mongol is always
-distinguished by a yellow tone, sometimes a light pea green, or even
-white, sometimes a darker brownish yellow. Their hair is always stiff
-and black. The form of their skull is, in the great majority of cases,
-decidedly short (especially in Kalmucks, Baschkirs, etc.) but frequently
-of medium length (Tartars, Chinese, etc.) But among them we never meet
-with genuine long-headed men. The narrow openings of their eyes, which
-are generally slanting, their prominent cheek bones, broad noses, and
-thick lips are very striking, as well as the round form of their faces.
-The language of the Mongols is probably traceable to a common primaeval
-language; but the monosyllabic languages of the Indo-Chinese races, and
-the polysyllabic languages of the other Mongol races, stand in contrast
-as two main branches which separated at an early time. The monosyllabic
-tribes of the Indo-Chinese include the Tibetans, Birmans, Siamese, and
-Chinese. The other polysyllabic Mongols are divided into three races,
-namely: (1) the Coreo-Japanese (Coreans and Japanese); (2) the Altaians
-(Tartars, Kirgises, Kalmucks, Buriats, Tungusians); and (3) the Uralians
-(Samoiedes, Fins). The Magyars of Hungary are descended from the Fins.
-
-The _Polar men_ (Homo Arcticus) must be looked upon as a branch of the
-Mongolian human species. We comprise under this name the inhabitants of
-the Arctic Polar lands of both hemispheres, the Esquimaux (and
-Greenlanders) in North America, and the Hyperboreans in north-eastern
-Asia (Jukagirs, Tschuksches, Kuriaks, and Kamtschads). By adaptation to
-the Polar climate, this human race has become so peculiarly transformed
-that it may be considered as a distinct species. Their stature is low
-and of a square build; the formation of their skull of medium size or
-even long; their eyes narrow and slanting like the Mongols; their
-cheek-bones prominent, and their mouth wide. Their hair is stiff and
-black; the colour of their skin is of a light or dark brown tinge,
-sometimes more inclined to white or to yellow, like that of the Mongols,
-sometimes more to red, like that of the Americans. The languages of
-Polar men are as yet little known, but they differ both from the
-Mongolian and from the American. Polar men must probably be regarded as
-a remnant and a peculiarly adapted branch of that tribe of Mongols which
-emigrated from north-eastern Asia to North America, and populated that
-part of the earth.
-
-At the time of the discovery of America, that part of the earth was
-peopled (setting aside the Esquimaux) only by a single human species,
-namely, by the _Redskins_, or _Americans_ (Homo Americanus). Of all
-other human species they are most closely related to the two preceding.
-The form of their skull is generally a medium one, rarely short or
-long-headed. Their forehead broad and very low; their nose large,
-prominent, and frequently aquiline; their cheek-bones prominent; their
-lips rather thin than thick. The colour of their skin is characterised
-by a red fundamental tint, which is, however, sometimes pure copper-red,
-or light red, sometimes a deeper reddish brown, yellow brown or olive
-brown. The numerous languages of the various American races and tribes
-are extremely different, yet they agree in their original foundation.
-Probably America was first peopled from north-eastern Asia by the same
-tribe of Mongols from whom the Polar men (Hyperboreans and Esquimaux)
-have also branched. This tribe first spread in North America, and from
-thence migrated over the isthmus of Central America down to South
-America, at the extreme south of which the species degenerated very
-much by adaptation to the very unfavourable conditions of existence. But
-it is also possible that Mongols and Polynesians immigrated from the
-west and mixed with the former tribe. In any case the aborigines of
-America came over from the Old World, and did not, as some suppose, in
-any way originate out of American apes. Catarrhini, or Narrow-nosed
-Apes, never at any period existed in America.
-
-The three human species still to be considered--the Dravidas, Nubians,
-and Mediterranese--agree in several characteristics which seem to
-establish a close relationship between them, and distinguish them from
-the preceding species. The chief of these characteristics is the strong
-development of the beard, which in all other species is either entirely
-wanting or but very scanty. The hair of their heads is generally not so
-lank and smooth as in the five preceding species, but in most cases more
-or less curly. Other characteristics also seem to favour our classing
-them in one main group of curly-haired men (Euplocomi).
-
-The _Dravida man_ (Homo Dravida) seems to stand very near the common
-primary form of the Euplocomi, and perhaps of Lissotrichi. At present
-this primaeval species is only represented by the Deccan tribes in the
-southern part of Hindostan, and by the neighbouring inhabitants of the
-mountains on the north-east of Ceylon. But in earlier times this race
-seems to have occupied the whole of Hindostan, and to have spread even
-further. It shows, on the one hand, traits of relationship to the
-Australians and Malays; on the other, to the Mongols and Mediterranese.
-Their skin is either of a light or dark brown colour; in some tribes, of
-a yellowish brown, in others, almost black brown. The hair of their
-heads, as in Mediterranese, is more or less curled, neither quite
-smooth, like that of the Euthycomi, nor actually woolly, like that of
-the Ulotrichi. The strong development of the beard is also like that of
-the Mediterranese. The oval form of face seems partly to be akin to that
-of the Malays, partly to that of the Mediterranese. Their forehead is
-generally high, their nose prominent and narrow, their lips slightly
-protruding. Their language is now very much mixed with Indo-Germanic
-elements, but seems to have been originally derived from a very peculiar
-primaeval language.
-
-The _Nubian_ (Homo Nuba) has caused ethnographers no fewer difficulties
-than the Dravida species. By this name we understand not merely the real
-Nubians (Schangallas, or Dongolese), but also their near kinsmen, the
-Fulas, or Fellatas. The real Nubians inhabit the countries of the Upper
-Nile (Dongola, Schangalla, Barabra, Cordofan); the Fulas, or Fellatas,
-on the other hand, have thence migrated far westward, and now inhabit a
-broad tract in the south of the western Sahara, hemmed in between the
-Soudanians in the north and the Nigritos in the south. The Nubian and
-Fula races are generally either classed with negroes or with the Hamitic
-races (thus with Mediterranese), but are so essentially different from
-both that they must be regarded as a distinct species. In former times
-they very probably occupied a large part of north-eastern Africa. The
-skin of the Nubian and Fula races is of a yellowish or reddish brown
-colour, more rarely dark brown or approaching to black. Their hair is
-not woolly but curled, frequently even quite smooth; its colour is dark
-brown or black. Their beard is much more strongly developed than in
-negroes. The oval formation of their faces approaches more to the
-Mediterranean than to the Negro type. Their forehead is high and broad,
-their nose prominent and not flat, their lips not so protruding as in
-the negro. The language of the Nubian races seems to possess no
-relationship to those of genuine negroes.
-
-The _Caucasian_, or _Mediterranean man_ (Homo Mediterraneus), has from
-time immemorial been placed at the head of all races of men, as the most
-highly developed and perfect. It is generally called the Caucasian race,
-but as among all the varieties of the species, the Caucasian branch is
-the least important, we prefer the much more suitable appellation
-proposed by Friedrich Mueller, namely, that of Mediterranean, or Midland
-men. For the most important varieties of this species, which are
-moreover the most eminent actors in what is called "Universal History,"
-first rose to a flourishing condition on the shores of the
-Mediterranean. The former area of the distribution of this species is
-expressed by the name of "Indo-Atlantic" species, whereas at present it
-is spread over the whole earth, and is overcoming most of the other
-species in the struggle for existence. In bodily as well as in mental
-qualities, no other human species can equal the Mediterranean. This
-species alone (with the exception of the Mongolian) has had an actual
-history; it alone has attained to that degree of civilization which
-seems to raise man above the rest of nature.
-
-The characteristics which distinguish the Mediterranean from the other
-species of the race are well known. The chief of the external features
-is the light colour of the skin, which however exhibits all shades, from
-pure white or reddish white, through yellow or yellowish brown to dark
-brown or even black brown. The growth of the hair is generally strong,
-the hair of the head more or less curly, the hair of the beard stronger
-than in any of the other species. The form of the skull shows a great
-development in breadth; medium heads predominate upon the whole, but
-long and short heads are also widely distributed. It is only in this one
-species of men that the body as a whole attains that symmetry in all
-parts, and that equal development, which we call the type of perfect
-human beauty. The languages of all the races of this species can by no
-means be traced to a single common primaeval language; we must at least
-assume four radically different primaeval languages. In accordance with
-this we must also assume within this one species four different races,
-which are only connected at their root. Two of these races, the Basques
-and Caucasians, now exist only as small remnants. The Basques, which in
-earlier times peopled the whole of Spain and the south of France, now
-inhabit but a narrow tract of land on the northern coast of Spain, on
-the Bay of Biscay. The remnant of the Caucasian race (the Daghestans,
-Tschercassians, Mingrelians, and Georgians) are now confined to the
-districts of Mount Caucasus. The language of the Caucasians as well as
-that of the Basques is entirely peculiar, and can be traced neither to
-the Semitic nor to the Indo-Germanic primaeval languages.
-
-Even the languages of the two principal races of the Mediterranean
-species--the Semitic and Indo-Germanic--cannot be traced to a common
-origin, and consequently these two races must have separated at a very
-early period. Semites and Indo-Germani are descended from different
-ape-like men. The _Semitic_ race likewise separated at a very early
-period into two diverging branches, namely, into the _Egyptian_ and
-_Arabic_ branches. The _Egyptian_, or _African_ branch, the
-_Dyssemites_--which sometimes under the name of Hamites are entirely
-separated from the Semites--embraces the large group of Berbers, who
-occupy the whole of north Africa, and in earlier times also peopled the
-Canary Islands, and, finally, also the group of the Ethiopians, the
-Bedsha, Galla, Danakil, Somali, and other tribes which occupy all the
-north-eastern shores of Africa as far as the equator. The _Arabic_, or
-_Asiatic_ branch, that is, the _Eusemites_, also called Semites in a
-narrow sense, embrace the inhabitants of the large Arabian peninsula,
-the primaeval family of genuine Arabians ("primaeval type of the
-Semites"), and also the most highly developed Semitic groups, the Jews,
-or Hebrews, and the Aramaeans--the Syrians and Chaldaeans. A colony of the
-southern Arabs (the Himjarites), which crossed the Straits of
-Bab-el-Mandeb, has peopled Abyssinia.
-
-Lastly, the Indo-Germanic race, which has far surpassed all the other
-races of men in mental development, separated at a very early period,
-like the Semitic, into two diverging branches, the _Ario-Romaic_ and the
-_Slavo-Germanic_ branches. Out of the former arose on the one hand the
-_Arians_ (Indians and Iranians), on the other the _Graeco-Roman_ (Greeks
-and Albanians, Italians and Kelts). Out of the Slavo-Germanic branch
-were developed on the one hand the _Slavonians_ (Russian, Bulgarian,
-Tchec, and Baltic tribes), on the other the _Germani_ (Scandinavians and
-Germans, Netherlanders and Anglo-Saxons). August Schleicher has
-explained, in a very clear genealogical form, how the further
-ramifications of the Indo-Germanic race may be accurately traced in
-detail on the basis of comparative philology.(6) (Compare p. 331.)
-
-The total number of human individuals at present amounts to between
-1,300 and 1,400 millions. In our Tabular Survey (p. 333) 1,350 millions
-has been assumed as the mean number. According to an approximate
-estimate, as far as such a thing is possible, 1,200 millions of these
-are straight-haired men, only about 150 millions woolly-haired. The most
-highly developed species, Mongols and Mediterranese, far surpass all the
-other human species in numbers of individuals, for each of them alone
-comprises about 550 millions. (Compare Friederich Mueller's Ethnography,
-p. 30.) Of course the relative number of the twelve species fluctuates
-every year, and that too according to the law developed by Darwin, that
-in the struggle for life the more highly developed, the more favoured
-and larger groups of forms, possess the positive inclination and the
-certain tendency to spread more and more at the expense of the lower,
-more backward, and smaller groups. Thus the Mediterranean species, and
-within it the Indo-Germanic, have by means of the higher development of
-their brain surpassed all the other races and species in the struggle
-for life, and have already spread the net of their dominion over the
-whole globe. It is only the Mongolian species which can at all
-successfully, at least in certain respects, compete with the
-Mediterranean. Within the tropical regions, Negroes, Kaffres, and
-Nubians, as also the Malays and Dravidas, are in some measure protected
-against the encroachments of the Indo-Germanic tribes by their being
-better adapted for a hot climate; the case of the arctic tribes of the
-polar regions is similar. But the other races, which as it is are very
-much diminished in number, will sooner or later completely succumb in
-the struggle for existence to the superiority of the Mediterranean
-races. The American and Australian tribes are even now fast approaching
-their complete extinction, and the same may be said of the Papuans and
-Hottentots.
-
-In now turning to the equally interesting and difficult question of the
-relative _connection_, _migration_, and _primaeval home_ of the twelve
-species of men, I must premise the remark that, in the present state of
-our anthropological knowledge, any answer to this question must be
-regarded only as a provisional hypothesis. This is much the same as with
-any genealogical hypothesis which we may form of the origin of kindred
-animal and vegetable species, on the basis of the "Natural System." But
-the necessary uncertainty of these special hypotheses of descent, in no
-way shakes the absolute certainty of the general theory of descent. Man,
-we may feel certain, is descended from Catarrhini, or narrow-nosed apes,
-whether we agree with the polyphylites, and suppose each human species,
-in its primaeval home, to have originated out of a special kind of ape;
-or whether, agreeing with the monophylites, we suppose that all the
-human species arose only by differentiation from a single species of
-primaeval man (Homo primigenius).
-
-For many and weighty reasons we hold the monophyletic hypothesis to be
-the more correct, and we therefore assume a _single primaeval home_ for
-mankind, where he developed out of a long since extinct anthropoid
-species of ape. Of the five now existing continents, neither Australia,
-nor America, nor Europe can have been this primaeval home, or the
-so-called "Paradise," the "cradle of the human race." Most
-circumstances indicate southern Asia as the locality in question.
-Besides southern Asia, the only other of the now existing continents
-which might be viewed in this light is Africa. But there are a number of
-circumstances (especially chorological facts) which suggest that the
-primaeval home of man was a continent now sunk below the surface of the
-Indian Ocean, which extended along the south of Asia, as it is at
-present (and probably in direct connection with it), towards the east,
-as far as further India and the Sunda Islands; towards the west, as far
-as Madagascar and the south-eastern shores of Africa. We have already
-mentioned that many facts in animal and vegetable geography render the
-former existence of such a south Indian continent very probable.
-(Compare vol. i. p. 361.) Sclater has given this continent the name of
-Lemuria, from the Semi-apes which were characteristic of it. By assuming
-this Lemuria to have been man's primaeval home, we greatly facilitate the
-explanation of the geographical distribution of the human species by
-migration. (Compare the Table of Migrations XV., and its explanation at
-the end.)
-
-We as yet know of no fossil remains of the hypothetical primaeval man
-(Homo primigenius) who developed out of anthropoid apes during the
-tertiary period, either in Lemuria or in southern Asia, or possibly in
-Africa. But considering the extraordinary resemblance between the lowest
-woolly-haired men, and the highest man-like apes, which still exist at
-the present day, it requires but a slight stretch of the imagination to
-conceive an intermediate form connecting the two, and to see in it an
-approximate likeness to the supposed primaeval men, or ape-like men. The
-form of their skull was probably very long, with slanting teeth; their
-hair woolly; the colour of their skin dark, of a brownish tint. The hair
-covering the whole body was probably thicker than in any of the still
-living human species; their arms comparatively longer and stronger;
-their legs, on the other hand, knock-kneed, shorter and thinner, with
-entirely undeveloped calves; their walk but half erect.
-
-This ape-like man very probably did not as yet possess an actual human
-language, that is, an articulate language of ideas. Human speech, as has
-already been remarked, most likely originated after the divergence of
-the primaeval species of men into different species. The number of
-primaeval languages is, however, considerably larger than the number of
-the species of men above discussed. For philologists have hitherto not
-been able to trace the four primaeval languages of the Mediterranean
-species, namely, the Basque, Caucasian, Semitic, and Indo-Germanic to a
-single primaeval language. As little can the different Negro languages be
-derived from a common primaeval language; hence both these species,
-Mediterranean and Negro, are certainly _polyglottonic_, that is, their
-respective languages originated after the divergence of the speechless
-primary species into several races had already taken place. Perhaps the
-Mongols, the Arctic and American tribes, are likewise polyglottonic. The
-Malayan species is, however, _monoglottonic_; all the Polynesian and
-Sundanesian dialects and languages can be derived from a common, long
-since extinct primaeval language, which is not related to any other
-language on earth. All the other human species, Nubians, Dravidas,
-Australians, Papuans, Hottentots, and Kaffres are likewise
-monoglottonic. (Compare p. 333.)
-
-Out of speechless primaeval man, whom we consider as the common primary
-species of all the others, there developed in the first place--probably
-by natural selection--various species of men unknown to us, and now long
-since extinct, and who still remained at the stage of speechless ape-men
-(Alalus, or Pithecanthropus). Two of these species, a woolly-haired and
-a straight-haired, which were most strongly divergent, and consequently
-overpowered the others in the struggle for life, became the primary
-forms of the other remaining human species.
-
-The main branch of woolly-haired men (Ulotrichi) at first spread only
-over the southern hemisphere, and then emigrated partly eastwards,
-partly westwards. Remnants of the eastern branch are the Papuans in New
-Guinea and Melanesia, who in earlier times were diffused much further
-west (in further India and Sundanesia), and it was not until a late
-period that they were driven eastwards by the Malays. The Hottentots are
-the but little changed remnants of the western branch; they immigrated
-to their present home from the north-east. It was perhaps during this
-migration that the two nearly related species of Caffres and Negroes
-branched off from them; but it may be that they owe their origin to a
-peculiar branch of ape-like men.
-
-The second main branch of primaeval straight-haired men (Lissotrichi),
-which is more capable of development, has probably left a but little
-changed remnant of its common primary form--which migrated to the
-south-east--in the ape-like natives of Australia. Probably very closely
-related to these latter are the South Asiatic _primaeval Malays_, or
-_Promalays_, which name we have previously given to the extinct,
-hypothetical primary form of the other six human species. Out of this
-unknown common primary form there seem to have arisen three diverging
-branches, namely, the true Malays, the Mongols, and the Euplocomi; the
-first spread to the east, the second to the north, and the third
-westwards.
-
-The primaeval home, or the "Centre of Creation," of the Malays must be
-looked for in the south-eastern part of the Asiatic continent, or
-possibly in the more extensive continent which existed at the time when
-further India was directly connected with the Sunda Archipelago and
-eastern Lemuria. From thence the Malays spread towards the south-east,
-over the Sunda Archipelago as far as Borneo, then wandered, driving the
-Papuans before them, eastwards towards the Samoa and Tonga Islands, and
-thence gradually diffused over the whole of the islands of the southern
-Pacific, to the Sandwich Islands in the north, the Mangareva in the
-east, and New Zealand in the south. A single branch of the Malayan tribe
-was driven far westwards and peopled Madagascar.
-
-The second main branch of primaeval Malays, that is, the Mongols, at
-first also spread in Southern Asia, and, radiating to the east, north,
-and north-west, gradually peopled the greater part of the Asiatic
-continent. Of the four principal races of the Mongol species, the
-Indo-Chinese must perhaps be looked upon as the primary group, out of
-which at a later period the other Coreo-Japanese and Ural-Altaian races
-developed as diverging branches. The Mongols migrated in many ways from
-western Asia into Europe, where the species is still represented in
-northern Russia and Scandinavia by the Fins and Lapps, in Hungary by the
-kindred Magyars, and in Turkey by the Osmanlis.
-
-  PEDIGREE OF SEMITES
-
-  Amharites                +Moors+                                     +Jews+
-      |           Tigrites    |             Samaritans                (Hebrews)
-      |  Harrarites  |        |                 |       Phoenicians       |
-      |       |      |        |                 |              |          |
-      |       |      |        |              Chaldeans         |          |
-      \-------v------/        |      Syrians    |              \----v-----/
-       +Abyssinians+          |         |       |               Canaanites
-   Ekilians   |               |         |       |            (+Palestinese+)
-      |       |               |         \---v---/                   |
-      |   Himiarites          |         +Aramaeans+                  |
-      |       |               |             |                       |
-      |       |               |             |                       |
-      \---v---/               |             |                       |
-       +South+             +North+          \----------v------------/
-      +Arabians+          +Arabians+             +Primaeval Jews+
-          |                   |                  +North-Semites+
-          \-------v-----------/                        |
-       +Arabians+ (+South Semites+)                    |
-                     |                                 |
-                     |                                 |
-                     \----------------------------------------v-----/
-          Guanchites                           +Eusemites+ (+Primaeval Semites+)
-    Schuluhs  |            Algerians            (Semites in a narrow sense)
-       |      |   Tunese      |                \------------------------v---/
-       |      |     |         |                                         |
-       |      |     |         |   Tripolitans                           |
-       \---v---/    |         |        |                                |
-       Moroccans    \----v----/        |       +Tuaric+                 |
-           |           Cabyles         |     (+Imoscharh+)              |
-           |             |             |           |                    |
-          \--------------v--------------/          |                    |
-                +Berbers+ (+Amazirh+)              |                    |
-    Gallites             |                         |                    |
-       |   Somalites     |                         |                    |
-       |       |         \------------v-------------/                   |
-       \---v---/  Bedschites        +Libians+         Babylonians   +Eusemites+
-           |          |   Egyptians    |        Primaeval   |            |
-           |          |   (+Copts+)    |       Phoenicians |  Assyrians |
-           \----v-----/       |        |           |       |      |     |
-           +Ethiopians+       |        |           |       |      |     |
-                |             |        |           |       |      |     |
-                |             |        |           |       |      |     |
-               \------------v----------/           \-------v------/     |
-                  +Ancient Egyptians+               +Mesopotamians+     |
-                            |                          (extinct)        |
-                            |                              |            |
-                            |                              |            |
-                            \------------v-----------------/            |
-                               +Hamites+ (+Dyssemites+)                 |
-                                         |                              |
-                                         \---------------v--------------/
-                                                    +Semites+
-
-             ----------------------------------------------------------------
-
-PEDIGREE OF THE INDO-GERMANI
-
-                    Ancient Prussians  +Anglo-Saxons+          +High Germans+
-      Lithuanians           |                | Low Germans            |
-            |        Letts  |                |      | Netherlanders   |
-            |          |    |                |      |        |        |
-            |          |    |                |      |        |        |
-            \-----v----/    |                |      \----v---/        |
-                  |         |                |    Ancient Saxons      |
-                  |         |                |           |            |
-                  \-------v-/                |           |            |
-                   +Baltic Races+            \------v----/            |
-             Sorbians, or |                      Saxons   Friesians   |
-                 Wends    |                         |         |       |
-            Poles  |      |                         |         |       |
-              |    |      |                         \----v----/       |
-    Czecs     |    |      |                        +Low Germans+      |
-      |       |    |      |                              |            |
-      |       |    |      |                              |            |
-    \--v-----------/      |  Scandinavians               \-----v------/
-  West Sclavonians        |        |          Goths        +Germans+
-       |         Russians |        |           |               |
-       |   South    |     |        |           |               |
-       | Sclavonians|     |        \----v----------------------/
-       |      |     |     |    +Primaeval Germans+               Ancient Britons
-       |      |     |     |             |                             |
-       |     \---v---/    |             |               Ancient Scots |  Gauls
-       |   South-eastern  |             | +Romans+        Irish |     |    |
-       |    Sclavonians   |             |    |             |    |     |    |
-       |         |        |             |    |             |    |     \--v-/
-       |         |        |             |    |             \--v-/   Brittanese
-       |         |        |             |    | +Latins+     Gaels        |
-       \----v----/        |             |    |     |          |          |
-      +Sclavonians+       |             |    |     |          |          |
-            |             |             |    \--v--/          \----v-----/
-            |             |             |    Italians           +Kelts+
-            \------v------/             |       |                  |
-             +Sclavo-Letts+             |       |                  |
-                   |                    |       \--------v---------/
-                   |                    |           +Italo-Kelts+
-                   \--v-----------------/                |
-             +Sclavo-Germans+  +Albanese+  +Greeks+      |
-                      |             |          |         |
-                      |             |          |         |
-                      |             \----v-----/         |
-                      |        +Primaeval Thracians+      |
-                      | +Indians+        |               |
-                      |     | +Iranians+ \-------v-------/
-                      |     |      |       +Graeco-Romans+
-                      |     \---v--/             |
-                      |     +Arians+             |
-                      |         |                |
-                      |         \-----v----------/
-                      |          +Ario-Romans+
-                      |               |
-                      \-------v-------/
-                        +Indo-Germans+
-
-
-On the other hand, a branch of the Mongols migrated from north-eastern
-Asia to America, which was probably in earlier times connected with the
-former continent by a broad isthmus. The Arctic tribes, or Polar men,
-the Hyperboreans of north-eastern Asia, and the Esquimaux of the
-extreme north of America, must probably be regarded as an offshoot of
-this branch, which became peculiarly degenerated by unfavourable
-conditions of existence. The principal portion of the Mongolian
-immigrants, however, migrated to the south, and gradually spread over
-the whole of America, first over the north, later over South America.
-
-The third and most important main branch of primaeval Malays, the
-curly-haired races, or Euplocomi, have probably left in the Dravidas of
-Hindostan and Ceylon, that species of man which differs least from the
-common primary form of the Euplocomi. The principal portion of the
-latter, namely, the Mediterranean species, migrated from their primaeval
-home (Hindostan?) westwards, and peopled the shores of the
-Mediterranean, south-western Asia, north Africa, and Europe. The
-Nubians, in the north-east of Africa, must perhaps be regarded as an
-offshoot of the primaeval Semitic tribes, who migrated far across central
-Africa almost to the western shores. The various branches of the
-Indo-Germanic race have deviated furthest from the common primary form
-of ape-like men. During classic antiquity and the middle ages, the
-Romanic branch (the Graeco-Italo-Keltic group), one of the two main
-branches of the Indo-Germanic species, outstripped all other branches in
-the career of civilization, but at present the same position is occupied
-by the Germanic. Its chief representatives are the English and Germans,
-who are in the present age laying the foundation for a new period of
-higher mental development, in the recognition and completion of the
-theory of descent. The recognition of the theory of development and the
-monistic philosophy based upon it, forms the best criterion for the
-degree of man's mental development.
-
-
-SYSTEMATIC SURVEY OF THE TWELVE HUMAN SPECIES.
-
-   N.B.--Column A denotes the Average Number of the Population in
-   millions. Column B shows the Degree of the Phyletic Development of
-   the Species, thus Pr = Progressive Diffusion; Co = Comparative
-   Stability; Re = Retrogression and Extinction. Column C denotes the
-   Character of the Primaeval Language; Mn (Monoglottonic) signifies that
-   the Species had one Simple Primaeval Language; Pl (Polyglottonic) a
-   Compound Primaeval Language.
-
-
-  ----------------------+--------------------+--------+-------+--------+-----------------------------
-  _Tribe._              |    _Human          |   A.   |  B.   |   C.   |             _Home._
-                        |     Species._      |        |       |        |
-  ----------------------+--------------------+--------+-------+--------+-----------------------------
-
-  TUFT-HAIRED            {                   |        |       |
-  +Lophocomi+            {  1. PAPUAN        |   2    |  Re   |  Mn    { New Guinea and Melanesia,
-                         {                   |        |       |        { Philippine Islands, Malacca
-  (about 2 millions)     {  2. HOTTENTOT     | 1/20   |  Re   |  Mn    { The extreme south of Africa
-                         {                   |        |       |        { (The Cape)
-                                             |        |       |
-  FLEECY-HAIRED          {  3. KAFFRE        |   20   |  Pr   |  Mn    { South Africa (between 30 deg.
-                         {                   |        |       |        { S. Lat. and 5 deg. N. Lat.)
-  +Eriocomi+             {  4. NEGRO         |   130  |  Pr   |  Pl    { Central Africa (between the
-                         {                   |        |       |        { Equator and 30 deg. N. Lat.)
-  (about 150 millions)   {                   |        |       |
-                                             |        |       |
-                         {  5. AUSTRALIAN    |  1/12  |   Re  |  Mn    { Australia
-                         {  6. MALAY         |   30   |   Co  |  Mn    { Malacca, Sundanesia, Polynesia,
-                         {                   |        |       |        { and Madagascar
-  STRAIGHT-HAIRED        {                   |        |       |
-  +Euthycomi+            {  7. MONGOL        |   550  |   Pr  |  Mn?   { The greater part of Asia
-                         {                   |        |       |        { and northern Europe
-  (about 600 millions)   {  8. ARCTIC        |  1/25  |   Co  |  Pl?   { The extreme north-east of
-                         {     MAN           |        |       |        { Asia and the extreme north
-                         {                   |        |       |        { of America
-                         {  9. AMERICAN      |   12   |   Re  |  Mn?   { The whole of America with
-                         {                   |        |       |        { the exception of the extreme
-                         {                   |        |       |        { north
-                                             |        |       |
-                         { 10. DRAVIDAS      |   34   |   Co  |  Mn    { South Asia (Hindostan and
-                         {                   |        |       |        { Ceylon)
-                         {                   |        |       |
-                         { 11. NUBIAN        |   10   |   Co  |  Mn?   { Central Africa (Nubia and
-                         {                   |        |       |        { Fula-land)
-  CURLY-HAIRED           {                   |        |       |        { In all parts of the world,
-                         {                   |        |       |        { having migrated from South
-  +Euplocomi+            { 12. MEDITERRANEAN |  550   |  Pr   |  Pl    { Asia to North Africa and
-                         {                   |        |       |        { South Europe
-  (about 600 millions)   {                   |        |       |
-                         {                   |        |       |
-                                             |        |       |        { In all parts of the world,
-                           13. HYBRIDS       |   11   |   Pr  |  Pl    { but predominating in America
-                              OF THE         |        |       |        { and Asia
-                              SPECIES        |        |       |
-                         --------------------+--------+       |
-                               TOTAL              1350
-
-
-
-
-CHAPTER XXIV.
-
-OBJECTIONS AGAINST, AND PROOFS OF THE TRUTH OF, THE THEORY OF DESCENT.
-
-
-  Objections to the Doctrine of Filiation.--Objections of Faith
-  and Reason.--Immeasurable Length of the Geological
-  Periods.--Transition Forms between Kindred Species.--Dependence
-  of Stability of Form on Inheritance, and of the Variability of
-  Form on Adaptation.--Origin of very complicated Arrangement of
-  Organisation.--Gradual Development of Instincts and Mental
-  Activities.--Origin of a priori Knowledge from Knowledge a
-  posteriori.--The Knowledge requisite for the Correct
-  Understanding of the Doctrine of Filiation.--Necessary
-  Interaction between Empiricism and Philosophy.--Proofs of the
-  Theory of Descent.--Inner Causal Connection between all the
-  Biological Series of Phenomena.--The Direct Proof of the Theory
-  of Selection.--Relation of the Theory of Descent to
-  Anthropology.--Proofs of the Animal Origin of Man.--The Pithecoid
-  Theory as an Inseparable Part of the Theory of
-  Descent.--Induction and Deduction.--Gradual Development of the
-  Human Mind.--Body and Mind.--Human Soul and Animal Soul.--A Glance
-  at the Future.
-
-
-If in these chapters I may hope to have made the Theory of Descent seem
-more or less probable, and to have even convinced some of my readers of
-its unassailable truth, yet I am by no means unconscious that, to most
-of them, during the perusal of my explanations, a number of objections
-more or less well founded must have occurred. Hence it seems absolutely
-necessary at the conclusion of our examination to refute at least the
-most important of these, and at the same time, on the other hand, once
-more to set forth the convincing arguments which bear testimony to the
-truth of the theory of development.
-
-The objections which are raised to the doctrine of descent may be
-divided into two large groups: objections of faith and objections of
-reason. The objections of the first group originate in the infinitely
-varied forms of faith held by human individuals, and need not here be
-taken into consideration at all. For, as I have already remarked at the
-beginning of this book, science, as an objective result of sensuous
-experience, and of the striving of human reason after knowledge, has
-nothing whatever to do with the subjective ideas of faith, which are
-preached by a single man as the direct inspirations or revelations of
-the Creator, and then believed in by the dependent multitude. This
-belief, very different in different nations, only begins, as is well
-known, where science ends. Natural Science believes, according to the
-maxim of Frederick the Great, "that every one may go to heaven in his
-own fashion," and only necessarily enters into conflict with particular
-forms of faith where they appear to set a limit to free inquiry and a
-goal to human knowledge, beyond which we are not to venture. Now this is
-certainly the case here in the highest degree, for the Theory of
-Development applies itself to the solution of the greatest of scientific
-problems--that of the creation, the coming into existence of things;
-more especially the origin of organic forms, and of man at their head.
-It is here certainly the right as well as the sacred duty of free
-inquiry, to fear no human authority, and courageously to raise the veil
-from the image of the Creator, unconcerned as to what natural truth may
-lie concealed beneath. The only Divine revelation which we recognise as
-true, is written everywhere in nature, and to every one with healthy
-senses and a healthy reason it is given to participate in the unerring
-revelation of this holy temple of nature, by his own inquiry and
-independent discovery.
-
-If we, therefore, here disregard all objections to the Doctrine of
-Descent which may be raised by the priests of the different religious
-faiths, we must nevertheless endeavour to refute the most important of
-those objections which seem more or less founded on science, and which
-we grant might, at first sight, to a certain extent captivate us and
-deter us from adopting the Doctrine of Descent. Many persons seem to
-think the length of the periods of time required the most important of
-these objections. We are not accustomed to deal with such immense
-periods as are necessary for the history of the creation. It has already
-been mentioned that the periods, during which species originated by
-gradual transmutation, must not be calculated by single centuries, but
-by hundreds and by millions of centuries. Even the thickness of the
-stratified crust of the earth, the consideration of the immense space of
-time which was requisite for its deposition from water, taken together
-with the periods of elevation between the periods of depression,
-indicate a duration of time of the organic history of the earth which
-the human intellect cannot realize. We are here in much the same
-position as an astronomer in regard to infinite space. In the same way
-as the distances between the different planetary systems are not
-calculated by miles but by Sirius-distances, each of which comprises
-millions of miles, so the organic history of the earth must not be
-calculated by thousands of years, but by palaeontological or geological
-periods, each of which comprises many thousands of years, and perhaps
-millions, or even, milliards, of thousands of years. It is of little
-importance how high the immeasurable length of these periods may be
-approximately estimated, because we are in fact unable with our limited
-power of imagination to form a true conception of these periods, and
-because we do not as in astronomy possess a secure mathematical basis
-for fixing the approximate length of duration in numbers. But we most
-positively deny that we see any objection to the theory of development
-in the extreme length of these periods which are so completely beyond
-the power of our imagination. It is, on the contrary, as I have already
-explained in one of the preceding chapters, most advisable, from a
-strictly philosophical point of view, to conceive these periods of
-creation to be as long as possible, and we are by so much the less in
-danger of losing ourselves in improbable hypotheses, the longer we
-conceive the periods for organic processes of development to have been.
-The longer, for example, we conceive the Permian period to have been,
-the easier it will be for us to understand how the important
-transmutations took place within it which so essentially distinguish the
-fauna and flora of the Coal period from that of the Trias. The great
-disinclination which most persons have to assume such immeasurable
-periods, arises mainly from the fact of our having in early youth been
-brought up in the notion that the whole earth is only some thousands of
-years old. Moreover, human life, which at most attains the length of a
-century, is an extremely short space of time, and is not suitable as a
-standard for the measurement of geological periods. Our life is a
-single drop in the ocean of eternity. The reader may call to mind the
-duration of life of many trees which is more than fifty times as long;
-for example, the dragon-trees (Dracaena) and monkey bread-fruit trees
-(Adansonia), whose individual life exceeds a period of five thousand
-years; and, on the other hand, the shortness of the individual life of
-many of the lower animals, for example, the infusoria, where the
-individual, as such, lives but a few days, or even but a few hours,
-contrasts no less strongly with human longevity. This comparison brings
-the relative nature of all measurement of time very clearly before us.
-If the theory of development be true at all, there must certainly have
-elapsed immense periods, utterly inconceivable to us, during which the
-gradual historical development of the animal and vegetable kingdom
-proceeded by the slow transformation of species. There is, however, not
-a single reason for accepting a definite limit for the length of these
-periods of development.
-
-A second main objection which many, and more especially systematic
-zoologists and botanists, raise against the theory of descent, is that
-no _transition forms_ between the different species can be found,
-although according to the theory of descent they ought to be found in
-great numbers. This objection is partly well founded and partly not so,
-for there does exist an extraordinarily large number of transition forms
-between living, as well as between extinct species, especially where we
-have an opportunity of seeing and comparing very numerous individuals of
-kindred species. Those careful investigators of individual species who
-so frequently raise this objection are the very persons whom we
-constantly find checked in their special series of investigations by the
-really insuperable difficulty of sharply distinguishing individual
-species. In all systematic works, which are in any degree thorough, one
-meets with endless complaints, that here and there species cannot be
-distinguished because of the excessive number of transition forms. Hence
-every naturalist defines the limit and the number of individual species
-differently. Some zoologists and botanists, as I mentioned (vol. i. p.
-276), assume in one and the same group of organisms ten species, others
-twenty, others a hundred or more, while other systematic naturalists
-again look upon these different forms only as varieties of a single
-"good" species. In most groups of forms there is, in fact, a
-superabundance of transition forms and intermediate stages between the
-individual species.
-
-It is true that in many species the forms of transition are actually
-wanting, but this is easily explained by the principle of divergence or
-separation, the importance of which I have already explained. The
-circumstance that the struggle for existence is the more active between
-two kindred forms the closer they stand to each other, must necessarily
-favour the speedy extinction of the connecting intermediate forms
-between the two divergent species. If one and the same species produce
-diverging varieties in different directions, which become new species,
-the struggle between these new forms and the common primary form will be
-the keener the less they differ from one another; but the stronger the
-divergence the less dangerous the struggle. Naturally therefore, it is
-principally the connecting intermediate forms which will in most cases
-quietly die out, while the most divergent forms remain and reproduce
-themselves as distinct "new species." In accordance with this, we in
-fact no longer find forms of transition leading to those groups which
-are becoming extinct, as, for example, among birds, are the ostriches;
-and among mammals, the elephants, giraffes, Semi-apes, Edentata, and
-Ornithorhyncus. The groups of forms approaching their extinction no
-longer produce new varieties, and naturally the species are what is
-called "good," that is, the species are distinctly different from one
-another. But in those animal groups where development and progress are
-still active, where the existing species deviate into many new species
-by the formation of new varieties, we find an abundance of transition
-forms which cause the greatest difficulties to systematic naturalists.
-This is the case, for example, among birds with the finches; among
-mammals with most of the rodents (more especially with those of the
-mouse and rat kind), with a number of the ruminants and with genuine
-apes, more especially with the South American forms (Cebus), and many
-others. The continual development of species by the formation of new
-varieties here produces a mass of intermediate forms which connect the
-so-called "good" species, which efface their boundaries, and render
-their sharp specific distinction completely illusory.
-
-The reason that this nevertheless does not cause a complete confusion of
-forms, nor a universal chaos in the structure of animals and vegetables,
-lies simply in the fact that there is a continual counteraction at work
-between progressive _adaptation_ on the one hand, and the _retentive_
-power of _inheritance_ on the other hand. The degree of stability and
-variability manifested by every organic form is determined solely by the
-actual condition of the equilibrium between these two opposite
-functions. _Inheritance is the cause of the stability of species,
-adaptation the cause of their modification._ When therefore some
-naturalists say that, according to the theory of descent, there ought to
-be a much greater variety of forms, and others again, that there ought
-to be a much greater equality of forms, the former under-estimate the
-value of inheritance and the latter the value of adaptation. _The ratio
-of the interaction between inheritance and adaptation determines the
-ratio of the stability and variability of organic species_ at any given
-period.
-
-Another objection to the theory of descent, which, in the opinion of
-many naturalists and philosophers is of great weight, is that it
-ascribes the origin of organs which act for a definite purpose to causes
-which are either aimless or mechanical in their operation. This
-objection seems to be especially important in regard to those organs
-which appear so excellently adapted for a certain definite purpose that
-the most ingenious mechanician could not invent a more perfect organ for
-the purpose. Such are, above all, the higher sense-organs of animals,
-the eye and ear. If the eyes and auditory apparatus of the higher
-animals alone were known to us, they would indeed cause great and
-perhaps insurmountable difficulties. How could we come to the conclusion
-that the extraordinarily great and wonderful degree of perfection and
-conformity to purpose which we perceive in the eyes and ears of higher
-animals, is in every respect attained solely by natural selection?
-Fortunately, however, comparative anatomy and the history of
-development help us here over all obstacles; for when in the animal
-kingdom we follow the gradual progress towards perfection of the eyes
-and ears, step by step, we find such a finely graduated series of
-improvement, that we can clearly follow the development of the most
-complex organs through all the stages towards perfection. Thus, for
-example, the eye in the lowest animal is a simple spot of pigment which
-does not yet reflect any image of external objects, but at most
-perceives and distinguishes the different rays of light. Later, we find
-in addition to this a sensitive nerve; then there gradually develops
-within the spot of pigment the first beginning of the lens, a refractive
-body which is now able to concentrate the rays of light and to reflect a
-definite image. But all the composite apparatus for the movement of the
-eye and its accommodation to variations of light and distance are still
-absent, namely, the various refractive media, the highly differentiated
-membrane of the optic nerve, etc., which are so perfectly constructed in
-higher animals. Comparative anatomy shows us an uninterrupted succession
-of all possible stages of transition, from the simplest organ to the
-most highly perfected apparatus, so that we can form a pretty correct
-idea of the slow and gradual formation of even such an exceedingly
-complex organ. The like gradual progress which we observe in the
-development of the organ during the course of individual development,
-must have taken place in the historical (phyletic) origin of the organ.
-
-Many persons when contemplating these most perfect organs--which
-apparently were purposely invented and constructed by an ingenious
-Creator for a definite function, but which in reality have arisen by the
-aimless action of natural selection--experience difficulties in arriving
-at a rational understanding of them, which are similar to those
-experienced by the uncivilized tribes of nature when contemplating the
-latest complicated productions of engineering. Savages who see a ship of
-the line, or a locomotive engine for the first time, look upon these
-objects as the productions of a supernatural being, and cannot
-understand how a man, an organism like themselves, could have produced
-such an engine. Even the uneducated classes of our own race cannot
-comprehend such an intricate apparatus in its actual workings, nor can
-they understand its purely mechanical nature. Most naturalists, however,
-as Darwin very justly remarks, stand in much the same position in regard
-to the forms of organisms as do savages to ships of the line and to
-locomotive engines. A rational understanding of the purely mechanical
-origin of organic forms can only be acquired by a thorough and general
-training in Biology, and by a special knowledge of comparative anatomy
-and the history of development.
-
-Among the remaining objections to the Theory of Descent, I shall here
-finally refer to and refute but one more, as in the eyes of many
-unscientific men it seems to possess great weight. How are we, from the
-Theory of Descent, to conceive of the origin of the mental faculties of
-animals, and more especially their specific expressions--the so-called
-instincts? This difficult subject has been so minutely discussed by
-Darwin in a special chapter of his chief work (the seventh), that I must
-refer the reader to it. We must regard instincts as essentially the
-habits of the soul acquired by adaptation, and transmitted and fixed by
-inheritance through many generations. Instincts are, therefore, like all
-other habits, which, according to the laws of cumulative adaptation
-(vol. i. p. 233) and established inheritance (vol. i. p. 216), lead to
-the origin of new functions, and thus also to new forms of the organs.
-Here, as everywhere, the interaction between function and organ goes
-hand in hand. Just as the mental faculties of man have been acquired by
-the progressive adaptation of the brain, and been fixed by continual
-transmission by inheritance, so the instincts of animals, which differ
-from them only in quantity, not in quality, have arisen by the gradual
-perfecting of their mental organ, that is, their central nervous system,
-by the interaction of Adaptation and Inheritance. Instincts, as is well
-known, are inherited, but experiences and, consequently, new adaptations
-of the animal mind, are also transmitted by inheritance; and the
-training of domestic animals to different mental activities, which wild
-animals are incapable of accomplishing, rests upon the possibility of
-mental adaptation. We already know a series of examples, in which such
-adaptations, after they had been transmitted through a succession of
-generations, finally appeared as innate instincts, and yet they have
-only been acquired from the ancestors of the animals. Inheritance has
-here caused the result of training to become instinct. The
-characteristic instincts of sporting dogs, shepherd's dogs, and other
-domestic animals, and the natural instincts of wild animals, which they
-possess at birth, were in the first place acquired by their ancestors by
-adaptation. They may in this respect be compared to man's "knowledge a
-priori," which, like all other knowledge, was originally acquired by our
-remote ancestors, "a posteriori," by sensuous experience. As I have
-already remarked, it is evident that "knowledge a priori" arose only by
-long-enduring transmission, by inheritance of acquired adaptations of
-the brain, out of originally empiric or experiential "knowledge a
-posteriori" (vol. i. p. 31).
-
-The objections to the Theory of Descent here discussed and refuted are,
-I believe, the most important which have been raised against it; I
-consider also that I have sufficiently proved to the reader their
-futility. The numerous other objections which besides these have been
-raised against the Theory of Development in general, or against its
-biological part, the Theory of Descent in particular, arise either from
-such a degree of ignorance of empirically established facts, or from
-such a want of their right understanding, and from such an incapacity to
-draw the necessary conclusions, that it is really not worth the trouble
-to go further into the refutation. There are only some general points in
-regard to which, I should like, in a few words, to draw attention.
-
-In the first place I must observe, that in order thoroughly to
-understand the doctrine of descent, and to be convinced of its absolute
-truth, it is indispensable to possess a general knowledge of the whole
-of the domain of biological phenomena. _The theory of descent is a
-biological theory_, and hence it may with fairness and justice be
-demanded that those persons who wish to pass a valid judgment upon it
-should possess the requisite degree of biological knowledge. Their
-possessing a special empiric knowledge of this or that domain of zoology
-or botany, is not sufficient; they must possess a _general insight into
-the whole series of phenomena_, at least in the case of one of the three
-organic kingdoms. They ought to know what universal laws result from the
-comparative morphology and physiology of organisms, but more especially
-from comparative anatomy, from the individual and the palaeontological
-history of development, etc.; and they ought to have some idea of the
-deep _mechanical, causal connection_ between all these series of
-phenomena. It is self-evident that a certain degree of general culture,
-and especially a philosophical education, is requisite; which is,
-however, unfortunately by many persons in our day, not considered at all
-necessary. _Without the necessary connection of empirical knowledge and
-the philosophical understanding of biological phenomena, it is
-impossible to gain a thorough conviction of the truth of the Theory of
-Descent._
-
-Now I ask, in the face of this first preliminary condition for a true
-understanding of the Theory of Descent, what we are to think of the
-confused mass of persons who have presumed to pass a written or oral
-judgment upon it of an adverse character? Most of them are unscientific
-persons, who either know nothing of the most important phenomena of
-Biology, or at least possess no idea of their deeper significance. What
-should we say of an unscientific person who presumed to express an
-opinion on the cell-theory, without ever having seen cells; or of one
-who presumed to question the vertebral-theory, without ever having
-studied comparative anatomy? And yet one may meet with such ridiculous
-arrogance any day in the history of the biological Theory of Descent.
-One hears thousands of unscientific and but half-educated persons pass a
-final judgment upon it, although they know nothing either of botany or
-of zoology, of comparative anatomy or the theory of tissues, of
-palaeontology or embryology. Hence it happens, as Huxley well says, that
-most of the writings published against Darwin are not worth the paper
-upon which they are written.
-
-We might add that there are many naturalists, and even celebrated
-zoologists and botanists, among the opponents of the Theory of Descent;
-but these latter are mostly old stagers, who have grown grey in quite
-opposite views, and whom we cannot expect, in the evening of their
-lives, to submit to a reform in their conception of the universe, which
-has become to them a fixed idea.
-
-It is, moreover, expressly to be remarked, that not only a general
-insight into the _whole_ domain of biological phenomena, but also a
-philosophical understanding of it, are the necessary preliminary
-conditions for becoming convinced of and adopting the Theory of Descent.
-Now we shall find that these indispensable preliminary conditions are,
-unfortunately, by no means fulfilled by the majority of naturalists of
-the present day. The immense amount of empirical facts with which the
-gigantic advances of modern natural science have recently made us
-acquainted has led to a prevailing inclination for the special study of
-single phenomena and of small and narrow domains. This causes the
-knowledge of other paths, and especially of Nature as a great
-comprehensive whole, to be in most cases completely neglected. Every one
-with sound eyes and a microscope, together with industry and patience
-for study, can in our day attain a certain degree of celebrity by
-microscopic "discoveries," without, however, deserving the name of a
-naturalist. This name is deserved only by him who not merely strives to
-_know_ the individual phenomena, but who also seeks to _discover_ their
-causal connection. Even in our own day, most palaeontologists examine and
-describe fossils without knowing the most important facts of embryology.
-Embryologists, on the other hand, follow the history of development of a
-particular organic individual, without having an idea of the
-palaeontological history of the whole tribe, of which fossils are the
-records. And yet these two branches of the organic history of
-development--ontogeny, or the history of the individual, and phylogeny,
-or the history of the tribe--stand in the closest causal connection, and
-the one cannot be understood without the other. The same may be said of
-the systematic and the anatomical part of Biology. There are even now,
-in zoology and botany, many systematic naturalists who work with the
-erroneous idea that it is possible to construct a natural system of
-animals and plants simply by a careful examination of the external and
-readily accessible forms of bodies, without a deeper knowledge of their
-internal structure. On the other hand, there are anatomists and
-histologists who think it possible to obtain a true knowledge of animal
-and vegetable bodies merely by a most careful examination of the inner
-structure of the body of some individual species, without the
-comparative examination of the bodily form of all kindred organisms. And
-yet here, as everywhere, the internal and external factors, to wit,
-Inheritance and Adaptation, stand in the closest mutual relation, and
-the individual can never be thoroughly understood without a comparison
-of it with the whole of which it is a part. To those one-sided
-specialists we should like in Goethe's words to say:--
-
-  We must, contemplating Nature,
-  Part as Whole, give equal heed to:
-  Nought is inward, nought is outward,
-  For the inner is the outer.[6]
-
-And again:--
-
-  Nature has neither kernel nor shell,
-  It is she that is All and All at once.[7]
-
-What is even more detrimental to the general understanding of nature as
-a whole than this one-sided tendency, is _the want of a philosophical
-culture_, and this applies to most of the naturalists of the present
-day. The various errors of the earlier speculative nature-philosophy
-made during the first thirty years of our century, have brought the
-whole of philosophy into such bad repute with the exact empirical
-naturalists, that they live in the strange delusion that it is possible
-to erect the edifice of natural science out of mere facts, without their
-philosophic connection; in short, out of mere knowledge, without the
-understanding of it. But as a purely speculative and absolutely
-philosophical system, which does not concern itself with the
-indispensable foundation of empirical facts, becomes a castle in the
-air, which the first real experiment throws to the winds; so, on the
-other hand, a purely empirical system, constructed of nothing but facts,
-remains a disorderly heap of stones, which will never deserve the name
-of an edifice. Bare facts established by experience are nothing but rude
-stones, and without their thoughtful valuation, without their
-philosophic connection, no science can be established. As I have already
-tried to impress upon my reader, the _strong edifice of true monistic
-science_, or what is the same thing, the _Science of Nature, exists only
-by the closest interaction, and the reciprocal penetration of philosophy
-and empirical knowledge_.
-
-This lamentable estrangement between science and philosophy, and the
-rude empiricism which is now-a-days unfortunately praised by most
-naturalists as "exact science," have given rise to those strange freaks
-of the understanding, to those gross insults against elementary logic,
-and to that incapacity for forming the simplest conclusions which one
-may meet with any day in all branches of science, but especially in
-zoology and botany. It is here that the neglect of a philosophical
-culture and training of the mind, directly avenges itself most
-painfully. It is not to be wondered at that the deep inner truth of the
-Theory of Descent remains a sealed book to those rude empiricists. As
-the common proverb justly says: they cannot see the wood for the trees.
-It is only by a more general philosophical study, and especially by a
-more strictly logical training of the mind, that this sad state of
-things can be remedied. (Compare Gen. Morph. i. 63; ii. p. 447.)
-
-If we rightly consider this circumstance, and if we further reflect upon
-it in connection with the empirical foundation of the philosophical
-theory of development, we shall at once see how we are placed respecting
-the oft-demanded _proofs of the theory of descent_. The more the
-doctrine of filiation has of late years made way for itself, and the
-more all thoughtful, younger naturalists, and all truly
-biologically-educated philosophers have become convinced of its inner
-truth and absolute necessity, the louder have its opponents called for
-actual proofs. The same persons who, shortly after the publication of
-Darwin's work, declared it to be "a groundless, fantastic system," an
-"arbitrary speculation," an "ingenious dream," now kindly condescend to
-declare that the theory of descent certainly is a scientific
-"_hypothesis_," but that it still requires to be "_proved_." When these
-remarks are made by persons who do not possess the requisite
-empirico-philosophical culture, nor the necessary knowledge in
-comparative anatomy, embryology, and palaeontology, we cannot be much
-offended, and we refer them to the study of those sciences. But when
-similar remarks are made by acknowledged specialists, by teachers of
-zoology and botany, who certainly ought to possess a general insight
-into the whole domain of their science, or who are actually familiar
-with the facts of those scientific domains, then we are really at a loss
-what to say. Those who are not satisfied with the treasures of our
-present empirical knowledge of nature as a basis on which to establish
-the Theory of Descent, will not be convinced by any other facts which
-may hereafter be discovered; for we can conceive no circumstances which
-would furnish stronger or a more complete testimony to the truth of the
-doctrine of filiation than is even now seen, for example, in the
-well-known facts of comparative anatomy and ontogeny. I must here again
-direct attention to the fact, _that all the great and general laws, and
-all the comprehensive series of phenomena of the most different domains
-of biology can only be explained and understood by the Theory of
-Development_ (and especially by its biological part, the Theory of
-Descent), and that without it they remain completely inexplicable and
-incomprehensible. _The internal causal connection_ between them all
-proves the Theory of Descent to be the greatest _inductive law_ of
-Biology.
-
-Before concluding, I will once more name all those series of inductions,
-all those general laws of Biology, upon which this comprehensive law of
-development is firmly based.
-
-(1.) _The palaeontological history of the development of organisms_, the
-gradual appearance and the historical succession of the different
-species and groups of species, the empirical laws of the palaeontological
-change of species, as furnished to us by the science of fossils, and
-more especially the _progressive differentiation and perfecting_ of
-animal and vegetable groups in the successive periods of the earth's
-history.
-
-(2.) _The individual history of development of organisms_, embryology
-and metamorphology, the gradual changes in the slow development of the
-body and its particular organs, especially _the progressive
-differentiation and perfecting_ of the organs and parts of the body in
-the successive periods of the individual development.
-
-(3.) _The inner causal connection between ontogeny and phylogeny_, the
-parallelism between the individual history of the development of
-organisms, and the palaeontological history of the development of their
-ancestors, a connection which is actually established by the laws of
-_Inheritance_ and _Adaptation_, and which may be summed up in the words:
-ontogeny, according to the laws of inheritance and adaptation, repeats
-in its large features the outlines of phylogeny.
-
-(4.) _The comparative anatomy of organisms_, the proof of the essential
-agreement of the inner structure of kindred organisms, in spite even of
-the greatest difference of external form in the various species; their
-explanation by the causal dependence of the internal agreement of the
-structure on _Inheritance_, the external dissimilarity of the bodily
-form on _Adaptation_.
-
-(5.) _The inner causal connection between comparative anatomy and the
-history of development_, the harmonious agreement between the laws of
-the gradual development, _the progressive differentiation and
-perfecting_, as they may be seen in comparative anatomy on the one hand,
-in ontogeny and palaeontology on the other.
-
-(6.) _Dysteleology, or the theory of purposelessness_, the name I have
-given to the _science of rudimentary organs_, of suppressed and
-degenerated, aimless and inactive, parts of the body; one of the most
-important and most interesting branches of comparative anatomy, which,
-when rightly estimated, is alone sufficient to refute the fundamental
-error of the teleological and dualistic conception of Nature, and to
-serve as the foundation of the mechanical and monistic conception of the
-universe.
-
-(7.) _The natural system of organisms_, the natural grouping of all the
-different forms of Animals, Plants, and Protista into numerous smaller
-or larger groups, arranged beside and above one another; the kindred
-connection of species, genera, families, orders, classes, tribes, etc.,
-more especially, however, the _arboriform branching character of the
-natural system_, which is the spontaneous result of a natural
-arrangement and classification of all these graduated groups or
-categories. The result attained in attempting to exhibit the
-relationships of the mere forms of organisms by a tabular classification
-is only explicable when regarded as the expression of their actual
-_blood relationship_; _the tree shape of the natural system_ can only be
-understood as the actual _pedigree of the organisms_.
-
-(8.) _The chorology of organisms_, the science of the local distribution
-of organic species, of their _geographical_ and _topographical
-dispersion over the surface of the earth_, over the heights of
-mountains and in the depths of the ocean, but especially the important
-phenomenon that every species of organism proceeds from a so-called
-"_centre of creation_" (more correctly a "_primaeval home_" or "_centre
-of distribution_"); that is, from a single locality, where it originated
-but once, and whence it spread.
-
-(9.) _The oecology of organisms_, the knowledge of the sum of the
-_relations of organisms to the surrounding outer world_, to organic and
-inorganic conditions of existence; the so-called "_economy of nature_,"
-the correlations between all organisms living together in one and the
-same locality, their adaptation to their surroundings, their
-modification in the struggle for existence, especially the circumstances
-of parasitism, etc. It is just these phenomena in "the economy of
-nature" which the unscientific, on a superficial consideration, are wont
-to regard as the wise arrangements of a Creator acting for a definite
-purpose, but which on a more attentive examination show themselves to be
-the necessary results of mechanical causes.
-
-(10.) _The unity of Biology as a whole_, the deep inner connection
-existing between all the phenomena named and all the other phenomena
-belonging to zoology, protistics, and botany, and which are simply and
-naturally explained by a single common principle. This principle can be
-no other than the common derivation of all the specifically different
-organisms from a single, or from several absolutely simple, primary
-forms like the Monera, which possess no organs. The Theory of Descent,
-by assuming this common derivation, throws a clear light upon these
-individual series of phenomena, as well as upon their totality, without
-which their deeper causal connection would remain completely
-incomprehensible to us. The opponents of the Theory of Descent can in no
-way explain any single one of these series of phenomena or their deeper
-connection with one another. So long as they are unable to do this, _the
-Theory of Descent remains the one adequate biological theory_.
-
-We should, on account of the grand proofs just enumerated, have to adopt
-Lamarck's Theory of Descent for the explanation of biological phenomena,
-even if we did not possess Darwin's Theory of Selection. The one is so
-completely and _directly proved_ by the other, and established by
-mechanical causes, that there remains nothing to be desired. The laws of
-_Inheritance_ and _Adaptation_ are universally acknowledged
-_physiological_ facts, the former traceable to _propagation_, the latter
-to the _nutrition_ of organisms. On the other hand, the _struggle for
-existence_ is a _biological_ fact, which with mathematical necessity
-follows from the general disproportion between the average number of
-organic individuals and the numerical excess of their germs. But as
-Adaptation and Inheritance in the struggle for life are in continual
-interaction, it inevitably follows that _natural selection_, which
-everywhere influences and continually changes organic species, must, by
-making use of _divergence of character_, produce new species. Its
-influence is further especially favoured by the active and passive
-_migrations_ of organisms, which go on everywhere. If we give these
-circumstances due consideration, the continual and gradual modification
-or transmutation of organic species will appear as a biological process,
-which must, according to causal law, of _necessity_ follow from the
-actual nature of organisms and their mutual correlations.
-
-That even the _origin of man_ must be explained by this general organic
-process of transmutation, and that it is simply as well as naturally
-explained by it, has, I believe, been sufficiently proved in my last
-chapter but one. I cannot, however, avoid here once more directing
-attention to the inseparable connection between this so-called "theory
-of apes," or "pithecoid theory," and the whole Theory of Descent. If the
-latter is the greatest _inductive law_ of biology, then it of necessity
-follows that the former is its most important _deductive law_. They
-stand and fall together. As all depends upon a right understanding of
-this proposition, which in my opinion is very important, and which I
-have therefore several times brought before the reader, I may be allowed
-to explain it here by an example.
-
-In all mammals known to us the centre of the nervous system is the
-spinal marrow and the brain, and the centre of the vascular system is a
-quadrupal heart, consisting of two principal chambers and two
-ante-chambers. From this we draw the general inductive conclusion that
-all mammals, without exception, those extinct, together with all those
-living species as yet unknown to us, as well as the species which we
-have examined, possess a like organization, a like heart, brain, and
-spinal marrow. Now if, as still happens every year, there be discovered
-in any part of the earth a new species of mammal, a new species of
-marsupial, or a new species of deer, or a new species of ape, every
-zoologist knows with certainty at once, without having examined its
-inner structure, that this species must possess a quadruple heart, a
-brain and spinal marrow, like all other mammals. Not a single naturalist
-would ever think of supposing that the central nervous system of this
-new species of mammal could possibly consist of a ventral cord with an
-oesophageal collar as in the insects, or of scattered pairs of knots as
-in the molluscs, or that its heart could be many-chambered as in flies,
-or one-chambered as in the tunicates. This completely certain and safe
-conclusion, although it is not based upon any direct experience, is a
-_deductive conclusion_. In the same way, as I have shown in a previous
-chapter, Goethe, from the comparative anatomy of mammals, established
-the general inductive conclusion that they all possess a mid jawbone,
-and afterwards drew from it the special deductive conclusion that man,
-who in all other respects does not essentially differ from other
-mammals, must also possess a like mid jawbone. He maintained this
-conclusion without having actually seen the human mid jawbone, and only
-proved its existence subsequently by actual observation (vol. i. p. 84).
-
-The process of _induction_ is a logical system of forming conclusions
-_from the special to the general_, by which we advance from many
-individual experiences to a general law; _deduction_, on the other hand,
-draws a conclusion _from the general to the special_, from a general law
-of nature to an individual case. Thus the _Theory of Descent_ is,
-without doubt, a great _inductive law_, empirically based upon all the
-biological experience cited above; the pithecoid theory, on the other
-hand, which asserts that man has developed out of lower, and in the
-first place out of ape-like mammals, is a _deductive law_ inseparably
-connected with the general inductive law.
-
-The pedigree of the human race, the approximate outlines of which I gave
-in the last chapter but one, of course remains in detail (like all the
-pedigrees of animals and plants previously discussed) a more or less
-approximate general hypothesis. This however does not affect the
-application of the theory of descent to man. Here, as in all
-investigations on the derivation of organisms, one must clearly
-distinguish between the general _theory_ of descent and the special
-_hypotheses_ of descent. The general _theory_ of descent claims full and
-lasting value, because it is an inductive law, based upon all the whole
-series of biological phenomena and their inner causal connection. Every
-special _hypothesis_ of descent, on the other hand, has its special
-value determined by the existing condition of our biological knowledge,
-and by the extent of the objective empirical basis upon which we
-deductively establish this particular hypothesis. Hence, all the
-individual attempts to obtain a knowledge of the pedigree of any one
-group of organisms possesses but a temporary and conditional value, and
-any special hypothesis relating to it will become the more and more
-perfect the greater the advance we make in the comparative anatomy,
-ontogeny, and palaeontology of the group in question. The more, however,
-we enter into genealogical details, and the further we trace the
-separate off-shoots and branches of the pedigree, the more uncertain and
-subjective becomes our special _hypothesis_ of descent on account of the
-incompleteness of our empirical basis. This however does no injury to
-the general _theory_ of descent, which remains as the indispensable
-foundation for really profound apprehension of biological phenomena.
-Accordingly, there can be no doubt that we can and must, with full
-assurance, regard the derivation of man--in the first place, from
-ape-like forms; farther back, from lower mammals, and thus continually
-farther back to lower stages of the vertebrata down to their lowest
-invertebrate roots, nay, even down to a simple plastid--as a general
-_theory_. On the other hand, the special tracing of the human pedigree,
-the closer definition of the animal forms known to us, which either
-actually belong to the ancestors of man, or at least stand in very close
-blood relationship to them, will always remain a more or less
-approximate _hypothesis_ of descent, all the more in danger of deviating
-from the real pedigree the nearer it endeavours to approach it by
-searching for the individual ancestral forms. This state of things
-results from the immense gaps in our palaeontological knowledge, which
-can, under no circumstances, ever attain to even an approximate
-completeness.
-
-A thoughtful consideration of this important circumstance at once
-furnishes the answer to a question which is commonly raised in
-discussing this subject, namely, the question of scientific _proofs for
-the animal origin of the human race_. Not only the opponents of the
-Theory of Descent, but even many of its adherents who are wanting in the
-requisite philosophical culture, look too much for "signs" and for
-special empirical advances in the science of nature. They await the
-sudden discovery of a human race with tails, or of a talking species of
-ape, or of other living or fossil transition forms between man and the
-ape, which shall fill the already narrow chasm between the two, and thus
-empirically "prove" the derivation of man from apes. Such special
-manifestations, were they ever so convincing and conclusive, would not
-furnish the proof desired. Unthinking persons, or those unacquainted
-with the series of biological phenomena, would still be able to maintain
-the objections to those special testimonies which they now maintain
-against our theory.
-
-The absolute certainty of the Theory of Descent, even in its application
-to man, is built on a more solid foundation; and its true inner value
-can never be tested simply by reference to individual experience, but
-only by a philosophical comparison and estimation of the treasures of
-all our biological experiences. The inestimable importance of the Theory
-of Descent is surely based upon this, that the theory follows of
-necessity (as a general inductive law) from the comparative synthesis of
-all organic phenomena of nature, and more especially from the triple
-parallelism of comparative anatomy, of ontogeny, and phylogeny; and the
-pithecoid theory under all circumstances (apart from all special proofs)
-remains as a special deductive conclusion which must of necessity be
-drawn from the general inductive law of the Theory of Descent.
-
-In my opinion, all depends upon a right understanding of this
-_philosophical foundation of the Theory of Descent_ and of the
-_pithecoid theory_ which is inseparable from it. Many persons will
-probably admit this, and yet at the same time maintain that all this
-applies only to the _bodily_, not to the _mental_ development of man.
-Now, as we have hitherto been occupied only with the former, it is
-perhaps necessary here to cast a glance at the latter, in order to show
-that it is also subject to the great general law of development. In
-doing this it is above all necessary to recollect that body and mind can
-in fact never be considered as distinct, but rather that both sides of
-nature are inseparably connected, and stand in the closest interaction.
-As even Goethe has clearly expressed it--"matter can never exist and act
-without mind, and mind never without matter." The artificial discord
-between mind and body, between force and matter, which was maintained by
-the erroneous dualistic and teleological philosophy of past times has
-been disposed of by the advances of natural science, and especially by
-the theory of development, and can no longer exist in face of the
-prevailing mechanical and monistic philosophy of our day. How human
-nature, and its position in regard to the rest of the universe, is to be
-conceived of according to the modern view, has been minutely discussed
-by Radenhausen in his "Isis,"(33) which is excellent and well worth
-perusal.
-
-With regard to the origin of the human mind or the soul of man, we, in
-the first place, perceive that in every human individual it develops
-from the beginning, step by step and gradually, just like the body. In a
-newly born child we see that it possesses neither an independent
-consciousness, nor in fact clear ideas. These arise only gradually when,
-by means of sensuous experience, the phenomena of the outer world affect
-the central nervous system. But still the little child is wanting in all
-those differentiated emotions of the soul which the full-grown man
-acquires only by the long experience of years. From this graduated
-development of the human soul in every single individual we can, in
-accordance with the inner causal connection between ontogeny and
-phylogeny, directly infer the gradual development of the human soul in
-all mankind, and further, in the whole of the vertebrate tribe. In its
-inseparable connection with the body, the human soul or mind has also
-had to pass through all those gradual stages of development, all those
-various degrees of differentiation and perfecting, of which the
-hypothetical series of human ancestors sketched in a late chapter gives
-an approximate representation.
-
-It is true that this conception generally greatly offends most persons
-on their first becoming acquainted with the Theory of Development,
-because more than all others it most strongly contradicts the
-traditional and mythological ideas, and the prejudices which have been
-held sacred for thousands of years. But like all other functions of
-organisms, the human soul must necessarily have historically developed,
-and the comparative or empirical study of animal psychology clearly
-shows that this development can only be conceived of as a gradual
-evolution from the soul of vertebrate animals, as a gradual
-differentiation and perfecting which, in the course of many thousands of
-years, has led to the glorious triumph of the human mind over its lower
-animal ancestral stages. Here, as everywhere, the only way to arrive at
-a knowledge of natural truth is to compare kindred phenomena, and
-investigate their development. Hence we must above all, as we did in the
-examination of the bodily development, compare the highest animal
-phenomena on the one hand with the lowest animal phenomena, and on the
-other with the lowest human phenomena. The final result of this
-comparison is this--that _between the most highly developed animal
-souls, and the lowest developed human souls, there exists only a small
-quantitative, but no qualitative difference_, and that this difference
-is much less than the difference between the lowest and the highest
-human souls, or than the difference between the highest and the lowest
-animal souls.
-
-In order to be convinced of this important result, it is above all
-things necessary to study and compare the mental life of wild savages
-and of children.(32) At the lowest stage of human mental development are
-the Australians, some tribes of the Polynesians, and the Bushmen,
-Hottentots, and some of the Negro tribes. Language, the chief
-characteristic of genuine men, has with them remained at the lowest
-stage of development, and hence also their formation of ideas has
-remained at a low stage. Many of these wild tribes have not even a name
-for animal, plant, colour, and such most simple ideas, whereas they have
-a word for every single, striking _form_ of animal and plant, and for
-every single sound or colour. Thus even the most simple abstractions are
-wanting. In many of these languages there are numerals only for one,
-two, and three: no Australian language counts beyond four. Very many
-wild tribes can count no further than ten or twenty, whereas some very
-clever dogs have been made to count up to forty and even beyond sixty.
-And yet the faculty of appreciating number is the beginning of
-mathematics! Nothing, however, is perhaps more remarkable in this
-respect, than that some of the wildest tribes in southern Asia and
-eastern Africa have no trace whatever of the first foundations of all
-human civilization, of family life, and marriage. They live together in
-herds, like apes, generally climbing on trees and eating fruits; they do
-not know of fire, and use stones and clubs as weapons, just like the
-higher apes. All attempts to introduce civilization among these, and
-many of the other tribes of the lowest human species, have hitherto been
-of no avail; it is impossible to implant human culture where the
-requisite soil, namely, the perfecting of the brain, is wanting. Not one
-of these tribes has ever been ennobled by civilization; it rather
-accelerates their extinction. They have barely risen above the lowest
-stage of transition from man-like apes to ape-like men, a stage which
-the progenitors of the higher human species had already passed through
-thousands of years ago.(44)
-
-Now consider, on the other hand, the highest stages of development of
-mental life in the higher vertebrate animals, especially birds and
-mammals. If, as is usually done, we divide the different emotions of the
-soul into three principal groups--sensation, will, and thought--we shall
-find in regard to every one of them, that the most highly developed
-birds and mammals are on a level with the lowest human beings, or even
-decidedly surpass them. The _will_ is as distinctly and strongly
-developed in higher animals as in men of character. In both cases it is
-never actually free, but always determined by a causal chain of ideas.
-(Compare vol. i. p. 237.) In like manner, the different degrees of will,
-energy, and passion are as variously graduated in higher animals as in
-man. The _affections_ of the higher animals are not less tender and warm
-than those of man. The fidelity and devotion of the dog, the maternal
-love of the lioness, the conjugal love and connubial fidelity of doves
-and love-birds are proverbial, and might serve as examples to many men.
-If these virtues are to be called "instincts," then they deserve the
-same name in mankind. Lastly, with regard to _thought_, the comparative
-consideration of which doubtless presents the most difficulties, this
-much may with certainty be inferred--especially from an examination of
-the comparative psychology of cultivated domestic animals--that the
-processes of thinking, here follow the same laws as in ourselves.
-Experiences everywhere form the foundation of conceptions, and lead to
-the recognition of the connection between cause and effect. In all
-cases, as in man, it is the path of induction and deduction which leads
-to the formation of conclusions. It is evident that in all these
-respects the most highly developed animals stand much nearer to man than
-to the lower animals, although they are also connected with the latter
-by a chain of gradual and intermediate stages. In Wundt's excellent
-"Lectures on the Human and Animal Soul,"(46) there are a number of
-proofs of this.
-
-Now, if instituting comparisons in both directions, we place the lowest
-and most ape-like men (the Austral Negroes, Bushmen, and Andamans,
-etc.), on the one hand, together with the most highly developed animals,
-for instance, with apes, dogs, and elephants, and on the other hand,
-with the most highly developed men--Aristotle, Newton, Spinoza, Kant,
-Lamarck, or Goethe--we can then no longer consider the assertion, that
-the mental life of the higher mammals has gradually developed up to that
-of man, as in any way exaggerated. If one must draw a sharp boundary
-between them, it has to be drawn between the most highly developed and
-civilized man on the one hand, and the rudest savages on the other, and
-the latter have to be classed with the animals. This is, in fact, the
-opinion of many travellers, who have long watched the lowest human races
-in their native countries. Thus, for example, a great English traveller,
-who lived for a considerable time on the west coast of Africa, says: "I
-consider the negro to be a lower species of man, and cannot make up my
-mind to look upon him as 'a man and a brother,' for the gorilla would
-then also have to be admitted into the family." Even many Christian
-missionaries, who, after long years of fruitless endeavours to civilize
-these lowest races, have abandoned the attempt, express the same harsh
-judgment, and maintain that it would be easier to train the most
-intelligent domestic animals to a moral and civilized life, than these
-unreasoning brute-like men. For instance, the able Austrian missionary
-Morlang, who tried for many years without the slightest success to
-civilize the ape-like negro tribes on the Upper Nile, expressly says:
-"that any mission to such savages is absolutely useless. They stand far
-below unreasoning animals; the latter at least show signs of affection
-towards those who are kind towards them, whereas these brutal natives
-are utterly incapable of any feeling of gratitude."
-
-Now, it clearly follows from these and other testimonies, that the
-mental differences between the lowest men and the animals are less than
-those between the lowest and the highest men; and if, together with
-this, we take into consideration the fact that in every single human
-child mental life develops slowly, gradually, and step by step, from the
-lowest condition of animal unconsciousness, need we still feel offended
-when told that the mind of the whole human race has in like manner gone
-through a process of slow, gradual, and historical development? Can we
-find it "degrading" to the human soul that, by a long and slow process
-of differentiation and perfecting, it has very gradually developed out
-of the soul of vertebrate animals? I freely acknowledge that this
-objection, which is at present raised by many against the pithecoid
-theory, is quite incomprehensible to me. On this point Bernhard Cotta,
-in his excellent "Geologie der Gegenwart," very justly remarks: "Our
-ancestors may be a great honour to us; but it is much better if we are
-an honour to them!"(31)
-
-Our Theory of Development explains the origin of man and the course of
-his historical development in the only natural manner. We see in his
-gradually ascensive development out of the lower vertebrata, the
-greatest triumph of humanity over the whole of the rest of Nature. We
-are proud of having so immensely outstripped our lower animal ancestors,
-and derive from it the consoling assurance that in future also, mankind,
-as a whole, will follow the glorious career of progressive development,
-and attain a still higher degree of mental perfection. When viewed in
-this light, the Theory of Descent as applied to man opens up the most
-encouraging prospects for the future, and frees us from all those
-anxious fears which have been the scarecrows of our opponents.
-
-We can even now foresee with certainty that the complete victory of our
-Theory of Development will bear immensely rich fruits--fruits which have
-no equal in the whole history of the civilization of mankind. Its first
-and most direct result--the complete reform of _Biology_--will
-necessarily be followed by a still more important and fruitful reform of
-_Anthropology_. From this new theory of man there will be developed a
-new _philosophy_, not like most of the airy systems of metaphysical
-speculation hitherto prevalent, but one founded upon the solid ground of
-Comparative Zoology. A beginning of this has already been made by the
-great English philosopher Herbert Spencer.(45) Just as this new monistic
-philosophy first opens up to us a true understanding of the real
-universe, so its application to practical human life must open up a new
-road towards moral perfection. By its aid we shall at last begin to
-raise ourselves out of the state of social barbarism in which,
-notwithstanding the much vaunted civilization of our century, we are
-still plunged. For, unfortunately, it is only too true, as Alfred
-Wallace remarks with regard to this, at the end of his book of travels:
-"Compared with our wondrous progress in physical science and its
-practical applications, our system of government, of administering
-justice, of national education, and our whole social and moral
-organisation remains in a state of barbarism."
-
-This social and moral barbarism we shall never overcome by the
-artificial and perverse training, the one-sided and defective teaching,
-the inner untruth and the external tinsel, of our present state of
-civilization. It is above all things necessary to make a complete and
-honest return to Nature and to natural relations. This return, however,
-will only become possible when man sees and understands his true "place
-in nature." He will then, as Fritz Ratzel has excellently remarked,(47)
-"no longer consider himself an _exception_ to natural laws, but begin to
-seek for what is lawful in his own actions and thoughts, and endeavour
-to lead a life _according_ to natural laws." He will come to arrange his
-life with his fellow-creatures--that is, the family and the state--not
-according to the laws of distant centuries, but according to the
-rational principles deduced from knowledge of nature. Politics, morals,
-and the principles of justice, which are still drawn from all possible
-sources, will have to be formed in accordance with natural laws only. An
-_existence worthy of man_, which has been talked of for thousands of
-years, will at length become a reality.
-
-The highest function of the human mind is perfect knowledge, fully
-developed consciousness, and the moral activity arising from it. "Know
-thyself!" was the cry of the philosophers of antiquity to their
-fellow-men who were striving to ennoble themselves. "Know thyself!" is
-the cry of the Theory of Development, not merely to the individual, but
-to all mankind. And whilst increased knowledge of self becomes, in the
-case of every individual man, a strong force urging to an increased
-attention to conduct, mankind as a whole will be led to a higher path of
-moral perfection by the knowledge of its true origin and its actual
-position in Nature. The simple religion of Nature, which grows from a
-true knowledge of Her, and of Her inexhaustible store of revelations,
-will in future ennoble and perfect the development of mankind far beyond
-that degree which can possibly be attained under the influence of the
-multifarious religions of the churches of the various
-nations,--religions resting on a blind belief in the vague secrets and
-mythical revelations of a sacerdotal caste. Future centuries will
-celebrate our age, which was occupied with laying the foundations of the
-Doctrine of Descent, as the new era in which began a period of human
-development, rich in blessings,--a period which was characterized by the
-victory of free inquiry over the despotism of authority, and by the
-powerful ennobling influence of the Monistic Philosophy.
-
-
-  FOOTNOTES:
-
-  [1] With the exception of a single specimen of the bones of a foot,
-  preserved in the cabinet of Amherst College.--E. R. L.
-
-  [2] The primary stock of the Coniferae divided into two branches at an
-  early period, into the Araucariae on the one hand, and the Taxaceae, or
-  yew-trees, on the other. The majority of recent Coniferae are derived
-  from the former. Out of the latter the third class of the
-  Gymnosperms--the Meningos, or Gnetaceae--were developed. This small but
-  very interesting class contains only three different genera--Gnetum,
-  Welwitschia, and Ephedra; it is, however, of great importance, as it
-  forms the transition group from the Coniferae to the Angiosperms, and
-  more especially to the Dicotyledons.
-
-  [3] "Ueber ein Aequivalent der takonischen Schiefer Nordamerikas in
-  Deutschland."
-
-  [4] The English word "Insects" might with advantage be used in the
-  Linnaean sense for the whole group of Arthropods. In this case the
-  Hexapod Insects might be spoken of as the Flies.--E. R. L.
-
-  [5] Weisbach: "Novara-Reise," Anthropholog. Theil.
-
-  [6]        Muesset im Naturbetrachten
-             Immer Eins wie Alles achten.
-             Nichts ist drinnen, Nichts ist drauszen,
-             Denn was innen, das ist auszen.
-
-  [7]        Natur hat weder Kern noch Schale,
-             Alles ist sie mit einem Male.
-
-
-
-
-LIST OF THE WORKS REFERRED TO IN THE TEXT BY FIGURES, THUS--(1),
-
-_The study of which is recommended to the Reader._
-
-
-1. _Charles Darwin_, On the Origin of Species by means of Natural
-Selection; or, the Preservation of Favoured Races in the Struggle for
-Life. London, 1859. 5th Edition, 1869.
-
-2. _Jean Lamarck_, Philosophie Zoologique, ou Exposition des
-Considerations relatives a l'histoire naturelle des animaux; a la
-diversite de leur organisation et des facultes, qu'ils en obtiennent;
-aux causes physiques, qui maintiennent en eux la vie et donnent lieu aux
-mouvemens, qu'ils executent; enfin, a celles qui produisent, les unes le
-sentiment, et les autres l'intelligence de ceux qui en sont doues. 2
-Tomes. Paris, 1809.
-
-3. _Wolfgang Goethe_, Zur Morphologie: Bildung und Umbildung organischer
-Naturen. Die Metamorphose der Pflanzen, 1790. Osteologie, 1786. Vortraege
-ueber die drei ersten Capitel des Entwurfs einer allgemeinen Einleitung
-in die vergleichende Anatomie, ausgehend von der Osteologie, 1786. Zur
-Naturwissenschaft im Allgemeinen, 1780-1832.
-
-(Wolfgang Goethe, Contributions to Morphology: Formation and
-Transformation of Organic Natures. The Metamorphosis of Plants, 1790.
-Osteology, 1786. Lectures on the first three chapters of an Attempt at a
-General Introduction to Comparative Anatomy, beginning with Osteology,
-1786. Contributions to the Science of Nature in general, 1780-1832.)
-
-4. _Ernst Haeckel_, Generelle Morphologie der Organismen: Allgemeine
-Grundzuege der organischen Formenwissenschaft, mechanisch begruendet durch
-die von Charles Darwin reformirte Descendenz-theorie. I. Band,
-Allgemeine Anatomie der Organismen, oder Wissenschaft von den
-entwickelten organischen Formen. II. Band, Allgemeine
-Entwickelungsgeschichte der Organismen, oder Wissenschaft von den
-entstehenden organischen Formen. Berlin, 1866.
-
-(Ernst Haeckel, General Morphology of Organisms; General Outlines of the
-Science of Organic Forms based on Mechanical Principles through the
-Theory of Descent as reformed by Charles Darwin. Vol. I., General
-Anatomy of Organisms; or, the Science of Fully Developed Organic Forms.
-Vol. II., General History of the Development of Organisms; or, the
-Science of Organic Forms in their Origin. Berlin, 1866.)
-
-5. _Louis Agassiz_, An Essay on Classification. Contributions to the
-Natural History of the United States. Boston. Vol. I., 1857.
-
-6. _August Schleicher_, Die Darwin'sche Theorie und die
-Sprachwissenschaft. Weimar, 1863.
-
-(August Schleicher, Darwin's Theory and the Science of Language. Weimar,
-1863.)
-
-7. _M. J. Schleiden_, Grundzuege der wissenschaftlichen Botanik (die
-Botanik als inductive Wissenschaft). 2 Baende. Leipzig, 1849.
-
-(M. J. Schleiden, Principles of Scientific Botany (Botany as an
-Inductive Science). 2 Vols. Leipzig, 1849. Translated by Edwin
-Lankester, M.D., F.R.S. London, 1849.)
-
-8. _Franz Unger_, Versuch einer Geschichte der Pflanzenwelt. Wien, 1852.
-
-(Franz Unger, Essay on the History of the Vegetable Kingdom. Vienna,
-1852.)
-
-9. _Victor Carus_, System der thierischen Morphologie. Leipzig, 1853.
-
-(Victor Carus, System of Animal Morphology. Leipzig, 1853.)
-
-10. _Louis Buechner_, Kraft und Stoff. Empirisch-naturphilosophische
-Studien in allgemein verstaendlicher Darstellung, Frankfort, 1855, 3
-Auflage. 1867, 9 Auflage.
-
-(Louis Buechner, Force and Matter. Studies in the Empirical Philosophy of
-Nature, treated popularly. Frankfort, 1855, 3rd Edition. 1867, 9th
-Edition.)
-
-11. _Charles Lyell_, Principles of Geology. London, 1830. 10th Edition,
-1868.
-
-12. _Albert Lange_, Geschichte des Materialismus und Kritik seiner
-Bedeutung in der Gegenwart. Iserlohn, 1866.
-
-(Albert Lange, History of Materialism, and a Criticism of its Importance
-at the Present Time. Iserlohn, 1866.)
-
-13. _Charles Darwin_, Voyage of the _Beagle_. London.
-
-14. _Charles Darwin_, The Variation of Animals and Plants under
-Domestication. 2 Vols. London, 1868.
-
-15. _Ernst Haeckel_, Studien ueber Moneren und andere Protisten, nebst
-einer Rede ueber Entwickelungsgang und Aufgabe der Zoologie. Mit 6
-Kupfertafeln. Leipzig, 1870.
-
-(Ernst Haeckel, Studies on the Monera and other Protista, together with
-a Discourse on the Evolution and the Problems of Zoology. With 6
-Copper-plates. Leipzig, 1870.)
-
-16. _Fritz Mueller_, Fuer Darwin. Leipzig, 1864.
-
-(Fritz Mueller, For Darwin. Translated by W. S. Dallas. London, Murray.)
-
-17. _Thomas Huxley_, On our Knowledge of the Causes of the Phenomena of
-Organic Nature. Six Popular Lectures. London, Hardwicke, 1862.
-
-18. _H. G. Broenn_, Morphologische Studien ueber die Gestaltungsgesetze
-der Naturkoerper ueberhaupt, und der Organischen insbesondere. Leipzig und
-Heidelberg, 1858.
-
-(H. G. Broenn, Morphological Studies on the Laws of Form of Natural
-Bodies in General, and of Organic Bodies in Particular. Leipzig and
-Heidelberg, 1858.)
-
-19. _H. G. Broenn_, Untersuchungen ueber die Entwickelungsgesetze der
-organischen Welt waehrend der Bildungszeit unserer Erdoberflaeche.
-Stuttgart, 1858.
-
-(H. G. Broenn, Investigations on the Laws of Development of the Organic
-World during the Time of the Formation of the Earth's Crust. Stuttgart,
-1858.)
-
-20. _Carl Ernst Baer_, Ueber Entwickelungsgeschichte der Thiere.
-Beobachtung und Reflexion. 2 Baende. 1828.
-
-(Carl Ernst Baer, On the History of the Development of Animals.
-Observation and Reflection. 2 Vols. 1828.)
-
-21. _Carl Gegenbaur_, Grundzuege der vergleichenden Anatomie. Leipzig,
-1859. 2 (Umgearbeitete) Auflage, 1870.
-
-(Carl Gegenbaur, Outlines of Comparative Anatomy. Leipzig, 1859. 2nd
-(Revised) Edition, 1870.)
-
-22. _Immanuel Kant_, Allgemeine Naturgeschichte und Theorie des Himmels,
-oder Versuch von der Verfassung und dem mechanischen Ursprunge des
-ganzen Weltgebaeudes nach Newton'schen Grundsaetzen abgehandelt.
-Koenigsberg, 1755.
-
-(Immanuel Kant, General History of Nature and Theory of the Heavens; or,
-Essay on the Constitution and the Mechanical Origin of the whole
-Universe treated according to Newton's Principles. Koenigsberg, 1755.)
-
-23. _Ernst Haeckel_, Die Radiolarien. Eine Monographie. Mit einem Atlas
-von 35 Kupfertafeln. Berlin, 1862.
-
-(Ernst Haeckel, The Radiolaria. A Monograph, with Atlas containing 35
-Copper-plates. Berlin, 1862.)
-
-24. _August Weismann_, Ueber den Einflusz der Isolirung auf die
-Artbildung. Leipzig, 1872.
-
-(August Weismann, On the Influence of Isolation on the Formation of
-Species. Leipzig, 1872.)
-
-25. _Ernst Haeckel_, Ueber die Enstehung und den Stammbaum des
-Menschengeschlechts. Zwei Vortraege in der Sammlung gemeinverstaendlicher
-wissenschaftlicher Vortraege, herausgegeben von Virchow und Holtzendorff.
-Berlin, 1868. 2 Auflage, 1870.
-
-(Ernst Haeckel, On the Origin and the Pedigree of the Human Race. Two
-Lectures in the Collection of Popular Scientific Lectures, edited by
-Virchow and Holtzendorff. Berlin, 1868. 2nd Edition, 1870.)
-
-26. _Thomas Huxley_, Evidences as to Man's Place in Nature. Three Parts:
-1. On the Natural History of the Man-like Apes. 2. On the Relations of
-Man to the Lower Animals. 3. On some Fossil Remains of Man. London,
-Williams & Norgate.
-
-27. _Carl Vogt_, Vorlesungen ueber den Menschen, seine Stellung in der
-Schoepfung und in der Geschichte der Erde. 2 Baende. Giessen, 1863.
-
-(Carl Vogt, Lectures on Man, his Place in Creation and in the History of
-the Earth. 2 Vols. Giessen, 1863.)
-
-28. _Friedrich Rolle_, Der Mensch, seine Abstammung und Gesittung im
-Lichte der Darwin'schen Lehre von der Art-Entstehung, und auf Grund der
-neueren geologischen Entdeckungen dargestellt. Frankfurt-a-M., 1866.
-
-(Friedrich Rolle, Man, his Derivation and Civilization, in the Light of
-Darwin's Theory of the Origin of Species, based on Recent Geological
-Discoveries. Frankfort-a-M., 1866.)
-
-29. _Eduard Reich_, Die allgemeine Naturlehre des Menschen. Giessen,
-1865.
-
-(Eduard Reich, The General Natural History of Man. Giessen, 1865.)
-
-30. _Charles Lyell_, The Antiquity of Man. London, Murray.
-
-31. _Bernhard Cotta_, Die Geologie der Gegenwart. Leipzig, 1866.
-
-(Bernhard Cotta, The Geology of the Present Day.)
-
-32. _Karl Zittel_, Aus der Urzeit. Bilder aus der Schoepfungsgeschichte.
-Muenchen, 1871.
-
-(Karl Zittel, Primaeval Times. Pictures from the History of Creation.
-Munich, 1871.)
-
-33. _C. Radenhausen_, Isis. Der Mensch und die Welt. 4 Baende. Hamburg,
-1863. 2 Auflage, 1871.
-
-(C. Radenhausen, Isis. Man and the Universe. 4 Vols. Hamburg, 1863. 2nd
-Edition, 1871.)
-
-34. _August Schleicher_, Ueber der Bedeutung der Sprache fuer die
-Naturgeschichte des Menschen. Weimar, 1865.
-
-(August Schleicher, On the Importance of Language to the Natural History
-of Man. Weimar, 1865).
-
-35. _Wilhelm Bleek_, Ueber den Ursprung der Sprache. Herausgegeben mit
-einem Vorwort von Ernst Haeckel. Weimar, 1868.
-
-(Wilhelm Bleek, On the Origin of Language. Edited and with a Preface by
-Ernst Haeckel. Weimar, 1868.)
-
-36. _Alfred Russel Wallace_, The Malayan Archipelago. London, Macmillan.
-
-37. _Ernst Haeckel_, Ueber Arbeitstheilung in Natur- und Menschenleben.
-Sammlung gemeinverstaendlicher wissenschaftlicher Vortraege, herausgegeben
-von Virchow und Holtzendorff. 4 Serie. 1869. Heft 78.
-
-(Ernst Haeckel, On Differentiation in Nature and in Human Life. A
-Collection of Popular Scientific Lectures, edited by Virchow and
-Holtzendorff. 4th Series. 1869. No. 78.)
-
-38. _Hermann Helmholtz_, Populaere wissenschaftliche Vortraege.
-Braunschweig, 1871.
-
-(Hermann Helmholtz, Popular Scientific Lectures. Brunswick, 1871.)
-
-39. _Alexander Humboldt_, Ansichten der Natur. Stuttgart, 1826.
-
-(Alexander Humboldt, Views of Nature. Stuttgart, 1826.)
-
-40. _Moritz Wagner_, Die Darwin'sche Theorie und das Migrationsgesetz
-der Organismen. Leipzig, 1868.
-
-(Moritz Wagner, Darwin's Theory and the Law of the Migration of
-Organisms. Leipzig, 1868.)
-
-41. _Rudolf Virchow_, Vier Reden ueber Leben und Kranksein. Berlin, 1862.
-
-(Rudolf Virchow, Four Discourses on Life and Disease. Berlin, 1862.)
-
-42. _Friedrich Mueller_, Ethnographie (Reise der oesterreichischen
-Fregatte Novara. Anthropologischer Theil. 3 Abtheilung). Wien, 1868.
-
-(Friedrich Mueller, Ethnography (Voyage of the Austrian Frigate _Novara_.
-Anthropological Part. 3rd Part). Vienna, 1868.)
-
-43. _Ludwig Buechner_, Die Stellung des Menschen in der Natur, in
-Vergangenheit, Gegenwart und Zukunft. Leipzig, 1870.
-
-(Ludwig Buechner, Man's Place in Nature in the Past, the Present, and the
-Future. Leipzig, 1870.)
-
-44. _John Lubbock_, Prehistoric Times. London, 1867.
-
-45. _Herbert Spencer_, A System of Philosophy. (1. First Principles. 2.
-Principles of Biology. 3. Principles of Psychology, etc.) London, 1867.
-2nd Edition.
-
-46. _Wilhelm Wundt_, Vorlesungen ueber die Menschen- und Thierseele.
-Leipzig, 1863.
-
-(Wilhelm Wundt, Lectures on the Human and Animal Soul. Leipzig, 1863.)
-
-47. _Fritz Ratzel_, Sein und Werden der organischen Welt. Eine populaere
-Schoepfungsgeschichte. Leipzig, 1869.
-
-(Fritz Ratzel, Nature and Origin of the Organic World. A Popular History
-of Creation. Leipzig, 1869.)
-
-48. _Charles Darwin_, The Descent of Man, and Selection in Relation to
-Sex. 2 Vols. London, 1871.
-
-
-
-
-APPENDIX.
-
-EXPLANATION OF THE PLATES.
-
-
-  PLATE FACING TITLE-PAGE.
-
-_Developmental History of a Calcareous Sponge_ (Olynthus). Compare vol.
-ii. p. 140. The egg of the Olynthus (Fig. 9), which represents the
-common ancestral form of all Calcareous Sponges, is a simple cell (Fig.
-1). From this there arises, by repeated division (Fig. 2), a globular,
-mulberry-like heap of numerous equi-formal cells (Morula, Fig. 3; vol.
-ii. p. 125.) As the result of the change of these cells into an outer
-series of clear ciliated cells (Exoderm) and an inner series of dark,
-non-ciliated cells (Entoderm), the ciliated larva, or Planula, makes its
-appearance. This is oval in shape, and forms a cavity in its centre
-(gastric cavity, or primitive stomach, Fig. 6 _g_, with an opening
-(mouth-opening, or primitive mouth, Fig. 6 _o_); the wall of the gastric
-cavity consists of two layers of cells, or germ-layers, the outer
-ciliated Exoderm (_e_) and the inner non-ciliated Entoderm (_i_). Thus
-arises the exceedingly important stomach-larva, or Gastrula, which
-reappears in the most different tribes of animals as a common larval
-form (Fig. 5, seen from the surface; Fig. 6, in long section. Compare,
-vol. ii. pp. 126 and 281). After the Gastrula has swum about for some
-time in the sea, it fastens itself securely to the sea-bottom, loses its
-outer vibratile processes, or cilia, and changes into the Ascula (Fig.
-7, seen from the surface; Fig. 8, in long section; letters as in Fig.
-6). This Ascula is the recapitulative form, according to the biogenetic
-fundamental law, the common ancestor of all Zoophytes, namely, the
-Protascus (vol. ii. pp. 129, 133). By the development of pores in the
-wall of the stomach and of three-rayed calcareous spicules, the Ascula
-changes into the Olynthus (Fig. 9.) In Fig. 9 a piece is cut out from
-the stomach-wall of the Olynthus in order to show the inside of the
-stomachal cavity, and the eggs which are forming on the surface (_g_).
-From the Olynthus the most various forms of Calcareous Sponges can
-develop. One of the most remarkable is the Ascometra (Fig. 10), a stock
-or colony from which different species, and in fact different generic
-forms, grow (on the left Olynthus, in the middle Nardorus, on the right
-Soleniscus, etc., etc.). Further details as to these most interesting
-forms, and their high importance for the Theory of Descent, may be found
-in my "Monograph of the Calcareous Sponges" (1872), especially in the
-first volume. (Compare vol. ii. pp. 160, 167).
-
-
-  PLATE I. (_Between pages 184 and 185, Vol. I._)
-
-_History of the Life of the most Simple Organism_, a Moneron (Protomyxa
-aurantiaca). Compare vol. i. p. 184, and vol. ii. p. 53. The plate is a
-smaller copy of the drawing in my "Monographie der Moneren" (Biologische
-Studien, 1 Heft, 1870; Taf. 1), of the developmental history of the
-Protomyxa aurantiaca; I have there also given a detailed description of
-this remarkable Moneron (pp. 11-30). I discovered this most simple
-organism in January, 1867, during a stay in Lanzarote, one of the Canary
-Islands; and moreover I found it either adhering to, or creeping about
-on the white calcareous shells of a small Cephalopod (vol. ii. p. 162),
-the Spirula Peronii, which float there in masses on the surface of the
-ocean, or are thrown up on the shore. The Protomyxa aurantiaca is
-distinguished from the other Monera by the beautiful and bright
-orange-red colour of its perfectly simple body, which consists merely of
-primaeval slime, or protoplasm. The fully developed Moneron is
-represented in Figs. 11 and 12, very much enlarged. When it is hungry
-(Fig. 11), there radiate from the surface of the globular corpuscule of
-plasm, quantities of tree-shaped, branching and mobile threads
-(pseudo-feet, or pseudopodia), which do not become retiformly
-connected. When, however, the Moneron eats (Fig. 12), the mucous threads
-become variously connected, form net-works and enclose the extraneous
-corpuscule which serves as food, which the threads afterwards draw into
-the interior of the Protomyxa. Thus in Fig. 12 (above on the right), a
-silicious and ciliated Whip-swimmer (Peridinium, vol. ii. pp. 51, 57),
-has just been caught by the extended mucous filaments, and has been
-drawn into the interior of the mucous globule, in which there already
-are several half digested silicious infusoria (Tintinoida), and Diatomeae
-(Isthmia). Now, when the Protomyxa has eaten and grown sufficiently, it
-draws in all its mucous filaments (Fig. 15), and contracts into the form
-of a globule (Fig. 16 and Fig. 1). In this state of repose the globule
-secretes a simple gelatinous covering (Fig. 2), and after a time
-subdivides into a large number of small mucous globules (Fig. 3). These
-soon commence to move, become pear-shaped (Fig. 4), break through the
-common covering (Fig. 5), and then swim about freely in the ocean by
-means of a delicate whip-shaped process, like the Flagellata (vol. ii.
-p. 57, Fig. 11). When they meet a Spirula shell, or any other suitable
-object, they adhere to it, draw in their whip, and creep slowly about on
-it by means of form-changing processes (Figs. 6, 7, 8), like Protamoebae
-(vol. i. p. 186, vol. ii. p. 52). These small mucous corpuscules take
-food (Figs. 9, 10), and attain their full grown form (Figs. 11, 12),
-either by simple growth or by several of them fusing to form a larger
-protoplasmic mass (Plasmodium, Figs. 13, 14).
-
-
-  PLATES II. AND III. (_Between pages 294 and 295, Vol. I._)
-
-_Germs or Embryos of four different Vertebrate Animals_, namely,
-Tortoise (_A_ and _E_), Hen (_B_ and _F_), Dog (_C_ and _G_), and Man
-(_D_ and _H_). Figs. _A_, _D_, an early stage of development; Figs. _E_,
-_H_, a later stage. All the eight embryos are represented as seen from
-the right side, the curved back turned to the left. Figs. _A_ and _B_
-are seven times enlarged, Figs. _C_ and _D_ five times, Figs. _E_ and
-_H_ four times. Plate II. exhibits the very close blood relationship
-between birds and reptiles; Plate III. that between man and the other
-mammals.
-
-
-  PLATE IV. (_Between pages 34 and 35, Vol. II._)
-
-_The Hand, or Fore Foot, of nine different Mammals._ This plate is
-intended to show the importance of Comparative Anatomy to Phylogeny, in
-as much as it proves how the internal skeleton of the limbs is
-continually preserved by _inheritance_, although the external form is
-extremely changed by _adaptation_. The bones of the skeleton of the hand
-are drawn in white lines on the brown flesh and skin which surrounds
-them. All the nine hands are represented in the same position, namely
-the wrist (where the arm would be joined to it) is placed above, whilst
-the ends of the fingers or toes are turned downwards. The thumb, or the
-first (large) fore-toe is on the left in every figure; the little
-finger, or fifth toe is to the right at the edge of the hand. Each hand
-consists of three parts, namely (i.) the _wrist_ (carpus), composed of
-two cross rows of short bones (at the upper side of the hand); (ii.) the
-_mid-hand_ (metacarpus), composed of five long and strong bones (marked
-in the centre of the hand by the numbers 1-5); and (iii.) the five
-_fingers_, or _fore toes_ (digiti), every one of which again consists of
-several (mostly from two to three), _toe-pieces_, or _phalanges_. The
-hand of _man_ (Fig. 1), in regard to its entire formation, stands
-midway between that of the two large human apes, namely, that of the
-_gorilla_ (Fig. 2), and that of the _orang_ (Fig. 3). The fore paw of
-the _dog_ (Fig. 4), is more different, and the hand or breast fin of the
-_seal_ (Fig. 5) still more so. The adaptation of the hand to the
-movement of swimming, and its transformation into a fin for steering, is
-still more complete in the _dolphin_ (Ziphius, Fig. 6). The extended
-fingers and bones of the central hand here have remained short and
-strong in the swimming membrane, but they have become extremely long and
-thin in the _bat_ (Fig. 7), where the hand has developed into a wing.
-The extreme opposite of the latter formation is the hand of the _mole_
-(Fig. 8), which has acquired a powerful spade-like form for digging,
-with fingers which have become extremely short and thick. What is far
-more like the human hand than these latter forms, is the fore paw of the
-lowest and most imperfect of all mammals, the Australian _beaked animal_
-(Ornithorhynchus, Fig. 9), which in its whole structure stands nearer to
-the common, extinct, primary form of mammalia, than any known species.
-Hence man differs less in the formation of the hand from this common
-primary form than from the bat, mole, dolphin, seal, and many other
-mammals.
-
-
-  PLATE V. (_Between pages 84 and 85, Vol. II._)
-
-_Monophyletic, or One-rooted Pedigree of the Vegetable Kingdom_,
-representing the hypothesis of the common derivation of all plants, and
-the historical development of the different groups of plants during the
-palaeontological periods of the earth's history. The horizontal lines
-denote the different smaller and larger periods of the organic history
-of the earth (which are spoken of in vol. ii. p. 14), and during which
-the strata containing fossils were deposited. The vertical lines
-separate the different main-classes and classes of the vegetable kingdom
-from one another. The arboriform and branching lines indicate, in an
-approximate manner, by their greater or less number and thickness, the
-greater or less degree of development, differentiation, and perfecting
-which each class probably attained in each geological period. (Compare
-vol. ii. pp. 82, 83.)
-
-
-  PLATE VI. (_Between pages 130 and 131, Vol. II._)
-
-_Monophyletic, or One-rooted Pedigree of the Animal Kingdom_,
-representing the _historical growth of the six animal tribes_ during the
-palaeontological periods of the organic history of the earth. The
-horizontal lines _g h_, _i k_, _l m_, and _n o_ divide the five large
-periods of the organic history of the earth one from another. The field
-_g a b h_ comprises the archilithic, the field _i g h k_, the
-palaeolithic, the field _l i k m_ the mesolithic, and the field _n l o m_
-the cenolithic period. The short, anthropolithic period is indicated
-by the line _n o_. (Compare vol. ii. p. 14.) The height of the separate
-fields corresponds with the relative length of the periods indicated by
-them, as they may approximately be estimated from the relative thickness
-of the neptunic strata deposited between them. (Compare vol. ii. p. 22.)
-The archilithic and primordial period alone, during which the
-Laurentian, Cambrian, and Silurian strata were deposited, was probably
-considerably longer than the four subsequent periods taken together.
-(Compare vol. ii. pp. 10, 20.) In all probability the two tribes of
-worms and Zoophytes attained their full development during the
-mid-primordial period (in the Cambrian system); the star-fishes and
-molluscs probably somewhat later (in the Silurian system); whereas the
-articulata and vertebrata are still increasing in variety and
-perfection.
-
-
-  PLATE VII. (_Between pages 146 and 147, Vol. II._)
-
-_Group of Animal-Trees_ (_Zoophytes, or Coelenterata_) _in the
-Mediterranean_. On the upper half of the plate is a swarm of swimming
-medusae and ctenophora; on the lower half a few bunches of corals and
-hydroid polyps adhering to the bottom of the sea. (Compare the system of
-Zoophytes, vol. ii. p. 132, and on the opposite page their pedigree.)
-Among the adhering Zoophytes at the bottom of the ocean there is, below
-on the right hand, a large coral-colony (1), which is closely akin to
-the red precious coral (Eucorallium), and like the latter belongs to the
-group of corals with eight rays (Octocoralla Gorgonida); the single
-individuals (or persons) of the branching stock have the form of a star
-with eight rays, consisting of eight tentacles, which surround the
-mouth. (Octocoralla, vol. ii. p. 143.) Directly below and in front of it
-(quite below on the right), is a small bush of hydroid polyps (2),
-belonging to the group of bell-polyps, or Campanulariae (vol. ii. p.
-146). A larger stock of hydroid polyps (3), belonging to the group of
-tube-polyps, or Tubullariae, rises, to the left, on the opposite side,
-with its long thin branches. At its base is spread a stock of silicious
-sponges (Halichondria) (4), with short, finger-shaped branches (vol.
-ii. p. 139). Behind it, below on the left (5), is a very large marine
-rose (Actinia), a single individual from the class of six-rayed corals
-(Hexacoralla, vol. ii. p. 143). Its low, cylindrical body has a crown of
-very numerous and large leaf-shaped tentacles. Below, in the centre of
-the ground (6), is a sea-anemone (Cereanthus) from the group of
-fourfold corals (Tetracoralla). Lastly, on a small hill on the bottom
-of the sea, there rises, on the right above the corals (1) a cup-polyp
-(Lucernaria), as the representative of the stalked-jellies.
-(Podactinaria, or Calycozoa, vol. ii. p. 144.) Its cup-shaped, stalked
-body (7) has eight globular clusters of small, knotted tentacles on its
-rim.
-
-Among the _swimming Zoophytes_ which occupy the upper half of Plate
-VII., the hydromedusae are especially remarkable, on account of their
-alteration of generation. (Compare vol. i. p. 206.) Directly above the
-Lucernaria (7) floats a small tiara jelly (Oceania), whose bell-shaped
-body has a process like a dome, the form of a papal tiara (8). From the
-opening of the bell there hangs a wreath of very fine and long
-tentacles. This Oceania is the offspring of a tube-polyp, resembling the
-adhering Tubularia below on the left (3). Beside this latter, on the
-left, swims a large but very delicate hair-jelly (AEquorea). Its
-disc-shaped, slightly arched body is just drawing itself together, and
-pressing water out of the cavity of the cup lying below (9). The
-numerous, long, and fine hair-like tentacles which hang down from the
-rim of the cup are drawn by the ejected water into a conical bunch,
-which towards the centre turns upwards like a collar, and is thrown into
-folds. Above, in the middle of the cavity of the cup, hangs the stomach,
-the mouth of which is surrounded by four lobes. This AEquorea is derived
-from a small bell-polyp, resembling the Campanularia (2). The small,
-slightly arched cap-jelly (Eucope), swimming above in the centre (10),
-is likewise derived from a similar bell-polyp. In these three last cases
-(8, 9, 10), as in the majority of the hydromedusae, the alternation of
-generation consists in the freely swimming medusa (8, 9, 10), arising by
-the formation of buds (therefore by non-sexual generation, vol. i. p.
-192), from adhering hydroid polyps (2, 3). These latter, however,
-originate out of the fructified eggs of the medusae (therefore by sexual
-generation, vol. i. p. 195). Hence the non-sexual, adhering generation
-of polyps (I., III., V., etc.) regularly alternates with the sexual,
-freely swimming generation of medusae (II., IV., VI., etc.). This
-alteration of generation can only be explained by the Theory of Descent.
-
-The same remark applies to a kindred form of propagation, which is still
-more remarkable, and which I discovered in 1864, near Nice, in the
-Elephant-jellies (Geryonida), and called _alloeogony_, or
-_alloeogenesis_. In this case two completely distinct forms of medusa
-are descended from one another; the larger and more highly developed
-generation (11), Geryonia, or Carmarina, is six-rayed, with six foliated
-sexual organs, and six very movable marginal filaments. From the centre
-of its bell-shaped cup, like the tongue of a bell, hangs a long
-proboscis, at the end of which is the opening of the mouth and stomach.
-In the cavity of the stomach is a long, tongue-shaped bunch of buds
-(which on Plate VII. (_n_) is extended from the mouth on the left like a
-tongue). On this tongue, when the Geryonia is sexually ripe, there bud a
-number of small medusae. They are, however, not Geryoniae, but belong to
-an entirely distinct but very different form of medusa, namely, to the
-genus Cunina, of the family of the _AEginida_. This Cunina (12) is very
-differently constructed; it has a flat, semi-globular cup without
-proboscis, consists in early life of six divisions, later of sixteen,
-and has sixteen bag-shaped sexual organs, and sixteen short, stiff, and
-strongly curved tentacles. A further explanation of this wonderful
-alloeogenesis may be found in my "Contributions to the Natural History
-of the Hydromedusae." (_Leipzig_, Englemann, 1865), the first part of
-which contains a monograph of the Elephant-jellies, or Geryonida,
-illustrated by six copper-plates.
-
-Even more interesting and instructive than these remarkable relations
-are the vital phenomena of the _Siphonophora_, whose wonderful
-polymorphism I have frequently spoken of, and described in a popular
-manner in my lecture on "Differentiation in Nature and Human Life."(37)
-(Compare vol. i. p. 270, and vol. ii. p. 140.) An example of this is
-given in Plate VII. in the drawing of the beautiful Physophora (13).
-This swimming stock or colony of hydromedusae is kept floating on the
-surface of the sea by a small swimming bladder filled with air, which in
-the drawing is seen rising above the surface of the water. Below it is a
-column of four pairs of swimming bells, which eject water, and thereby
-set the whole colony in motion. At the lower end of the column of
-swimming bells is a crown-shaped wreath of curved spindle-shaped
-_sensitive polyps_, which also serve as a covering, under the protection
-of which the other individuals of the stock (the eating, catching, and
-reproductive persons) are hidden. The _ontogenesis_ of the Siphonophora
-(and especially of this Physophora), I first observed in Lanzerote, one
-of the Canary Islands, in 1866, and described in my "History of the
-Development of the Siphonophora," and added fourteen plates for its
-explanation. (Utrecht, 1869). It is rich in interesting facts, which can
-only be explained by the Theory of Descent.
-
-Another circumstance, which is also only explicable by the Theory of
-Descent, is the remarkable change of generation in the higher medusae,
-the disc-jellies (Discomedusae, vol. ii. p. 136), a representative of
-which is given at the top of Plate VII., in the centre (rather in the
-background), namely, a Pelagia (14). From the bottom of the bell-shaped
-cup, which is strongly arched and the rim of which is neatly indented,
-there hang four very long and strong arms. The non-sexual polyps, from
-which these disc-jellies are derived, are exceedingly simple primaeval
-polyps, differing very little from the common fresh-water polyp (Hydra).
-The alternation of generation in these Discomedusae has also been
-described in my lecture on Differentiation,(37) and there illustrated by
-the Aurelia by way of example.
-
-Finally, the last class of Zoophytes, the group of comb-jellies
-(Ctenophora, vol. ii. p. 142), has two representatives on Plate VII. To
-the left, in the centre, between the AEquorea (9), the Physophora (13),
-and the Cunina (12), is a long and thin band like a belt (15), winding
-like a snake; this is the large and splendid _Venus' girdle_ of the
-Mediterranean (Cestum), the colours of which are as varied as those of
-the rainbow. The actual body of the animal, which lies in the centre of
-the long belt, is very small, and constructed exactly like that of the
-_melon-jelly_ (Cydippe), which floats above to the left (16). On the
-latter are visible the eight characteristic fringed bands, or ciliated
-combs, of the ctenophora, and also two long tentacles which extend right
-across the page, and are fringed with still finer threads.
-
-
-  PLATES VIII. AND IX. (_Between pages 170 and 171, Vol. II._)
-
-_History of the Development of Star-fishes_ (_Echinoderma_, or
-_Estrella_). The two plates exhibit their alternation of generation
-(vol. ii. p. 168), with an example from each of the four classes of
-Star-fishes. The sea-stars (Asterida) are represented by Uraster (_A_),
-the sea-lilies (Crinoida) by Comatula (_B_), the sea-urchins (Echinida)
-by Echinus (_C_), and finally, the sea-cucumbers (Holothuriae) by Synapta
-(_D_). (Compare vol. ii. pp. 166 and 176.) The successive stages of
-development are marked by the numbers 1-6.
-
-Plate VIII. represents the individual development of the first and
-non-sexual generation of Star-fishes, that is, of the _nurses_ (usually,
-but erroneously, called larvae). These nurses possess the form-value of a
-simple, unsegmented worm-individual. Fig. 1 represents the egg of the
-four Star-fishes; and it, in all essential points, agrees with that of
-man and of other animals. (Compare vol. i. p. 297, Fig. 5.) As in man,
-the protoplasm of the egg-cell (the yolk) is surrounded by a thick,
-structureless membrane (zona pellucida), and contains a globular,
-cell-kernel (nucleus), as clear as glass, which again encloses a
-nucleolus. Out of the fertilised egg of the Star-fish (Fig. _A_ 1) there
-develops in the first place, by the repeated sub-division of cells, a
-globular mass of homogeneous cells (Fig. 6, vol. i. p. 299), and this
-changes into a very simple nurse, which has almost the same shape as a
-wooden shoe (Fig. _A_ 2-_D_ 2). The edge of the opening of the shoe is
-bordered by a fringe of cilia, the ciliary movements of which keep the
-microscopically small and transparent nurse swimming about freely in the
-sea. This fringe of cilia is marked in Fig. _A_ 2-_A_ 4, on Plate VII.,
-by the narrow alternately light and dark seam. The nurse then, in the
-first place, forms a perfectly simple intestinal canal for nutrition,
-mouth (_o_), stomach (_m_) and anus (_a_). Later, the windings of the
-fringe of cilia become more complicated, and there arise arm-like
-processes (Fig. _A_ 3-_D_ 3). In sea-stars (_A_ 4) and sea-urchins (_C_
-4) these arm-like processes, which are fringed with cilia, afterwards
-become very long. But in the case of sea-lilies (_B_ 3) and
-sea-cucumbers (_D_ 4), instead of this, the fringe of cilia, which at
-first, through winding in and out, forms one closed ring, changes
-subsequently into a succession of separate ciliated girdles, one lying
-behind the other.
-
-In the interior of this curious nurse there then develops, by a
-non-sexual process of generation, namely, by the formation of internal
-buds or germ-buds (round about the stomach), the second generation of
-Star-fishes, which later on become sexually ripe. This second
-generation, which is represented on Plate IX. in a fully developed
-condition, exists originally as a stock or cormus of five worms,
-connected at one end in the form of a star, as is most clearly seen in
-the sea-stars, the most ancient and original form of the star-fishes.
-The second generation, which grows at the expense of the first,
-appropriates only the stomach and a small portion of the other organs of
-the latter, but forms for itself a new mouth and anus. The fringe of
-cilia, and the other parts of the body of the nurse, afterwards
-disappear. The second generation (_A_ 5-_D_ 5), is at first smaller or
-not much larger than the nurse, whereas, by growth, it afterwards
-becomes more than a hundred times, or even a thousand times, as large.
-If the ontogeny of the typical representatives of the four classes of
-Star-fishes be compared, it is easily seen that the original kind of
-development has been best preserved in sea-stars (_A_) and sea-urchins
-(_C_) by inheritance, whereas in sea-lilies (_B_) and sea-cucumbers it
-has been suppressed according to the laws of abbreviated inheritance
-(vol. i. p. 212).
-
-Plate IX. shows the fully developed and sexually mature animals of the
-second generation from the mouth side, which, in the natural position of
-Star-fishes (when creeping at the bottom of the sea), in sea-stars (_A_
-6) and sea-urchins (_C_ 6), is below, in sea-lilies (_B_ 6) above, and
-in sea-cucumbers (_D_ 6) in front. In the centre we perceive, in all the
-four Star-fishes, the star-shaped, five-pointed opening of the mouth. In
-sea-stars, from each arm there extend several rows of little sucking
-feet, from the centre of the under-side of each arm to the end. In
-sea-lilies (_B_ 6), each arm is split and feather-like from its base
-upwards. In sea-urchins (_C_ 6) the five rows of sucking feet are
-divided by broader fields of spines. In sea-cucumbers, lastly (_D_ 6),
-on the worm-like body it is sometimes only the five rows of little feet,
-sometimes only the feathery tentacles surrounding the mouth, from five
-to fifteen (in this case ten), that are externally visible.
-
-
-  PLATES X. AND XI. (_Between pages 174 and 175, Vol. II._)
-
-_Historical Development of the Crab-fish_ (Crustacea).--The two plates
-illustrate the development of the different Crustacea from the nauplius,
-their common primaeval form. On Plate XI. six Crustacea, from six
-different orders, are represented in a fully developed state, whereas on
-Plate X. the early nauplius stages are given. From the essential
-agreement between the latter we may, on the ground of the fundamental
-law of biogeny, with full assurance maintain the derivation of the
-different Crustacea from a single, common primary form, a long since
-extinct Nauplius, as was first shown by Fritz Mueller in his excellent
-work "Fuer Darwin."(16)
-
-Plate X. represents the _early nauplius stages_ from the ventral side,
-so that the three pairs of legs, on the short, three-jointed trunk are
-distinctly visible. The first of these pairs of legs is simple and
-unsegmented, whereas the second and third pairs are forked. All three
-pairs are furnished with stiff bristles, which, through the paddling
-motion of the legs, serve as an apparatus for swimming. In the centre of
-the body, the perfectly simple, straight intestinal canal is visible,
-possessing a mouth in front, and an anal orifice behind. In front, above
-the mouth, lies a simple, single eye. All the six forms of nauplius
-entirely agree in all these essential characteristics of organization,
-whereas the six fully developed forms of Crustacea belonging to them,
-Plate XI., are extremely different in organisation. The differences of
-the six nauplius forms are confined to quite subordinate and unessential
-relations in regard to size of body, and the formation of the covering
-of the skin. If they could be met with in this form in a sexually mature
-condition, no zoologist would hesitate to regard them as six different
-species of one genus. (Compare vol. ii. p. 175.)
-
-Plate XI. represents those fully developed and sexually mature forms of
-Crustacea, as seen from the right side, which have ontogenetically
-(hence also phylogenetically) developed out of the six kinds of
-nauplius. Fig. _A c_ shows a freely swimming fresh-water crab (Limnetis
-brachyurus) from the order of the Leaf-foot Crabs (Phyllopoda), slightly
-enlarged. Of all the still living Crustacea, this order, which belongs
-to the legion of Gill-foot Crabs (Branchiopoda), stands nearest to the
-original, common primary form of nauplius. The Limnetis is enclosed in a
-bivalved shell, like a mussel. Our drawing (which is copied from Grube)
-represents the body of a female animal lying in the left shell; the
-right half of the shell has been removed. In front, behind the eye, we
-see the two feelers (antennae), and behind them the twelve leaf-shaped
-feet of the right side of the body, behind on the back (under the
-shell), the eggs. Above, in front, the animal is fixed to the shell.
-
-Fig. _B c_ represents a common, freely swimming fresh-water crab
-(Cyclops quadricornis) from the order of Oar-legged crabs (Eucopepoda),
-highly magnified. In front, below the eye, we see the two feelers of the
-right side, the foremost of which is longer than the hinder one. Behind
-these are the gills, and then the four paddling legs of the right side.
-Behind these are the two large egg-sacks, which, in this case, are
-attached to the end of the hinder part of the body.
-
-Fig. _C c_ is a parasitic Oar-legged crab (Lernaeocera esocina), from the
-order of fish lice (Siphonostoma). These peculiar crabs, which were
-formerly regarded as worms, have originated, by adaptation to a
-parasitical life, out of freely swimming, Oar-legged crabs (Eucopepoda),
-and belong to the same legion (Copepoda, vol. ii. p. 176). By adhering
-to the gills on the skin of fish or other crabs, and feeding on the
-juice of these creatures, they forfeited their eyes, legs, and other
-organs, and developed into formless, inarticulated sacks, which, on a
-mere external examination, we should never suppose to be animals. On the
-ventral side only there exist, in the shape of short, pointed bristles,
-the last remains of legs which have now almost entirely disappeared. Two
-of these rudimentary pairs of legs (the third and fourth) are seen in
-our drawing on the right. Above, on the head, we see thick, shapeless
-appendages, the lower ones of which are split. In the centre of the body
-is seen the intestinal canal, which is surrounded by a dark covering of
-fat. At its posterior end is the ovary, and the cement-glands of the
-female sexual apparatus. The two large egg-sacks hang externally (as in
-the Cyclops, Fig. _B_). Our Lernaeocera is represented in half profile,
-and is copied from Claus. (Compare Claus, "Die Copepoden-Fauna von
-Nizza. Ein Beitrag zur Characteristik der Formen und deren Abaenderungen
-im Sinne Darwins." Marburg, 1866).
-
-Fig. _D c_ represents a so-called "duck mussel" (Lepas anatifera), from
-the order of the Barnacle crabs (Cirripedia). These crabs, upon which
-Darwin has written a very careful monograph, are, like mussels, enclosed
-in a bivalved, calcareous case, and hence were formerly (even by Cuvier)
-universally regarded as a kind of mussel, or mollusc. It was only from a
-knowledge of their ontogeny, and their early nauplius form (_D n_, Plate
-VIII.), that their crustacean nature was proved. Our drawing shows a
-"duck mussel" of the natural size, from the right side. The right half
-of the bivalved shell has been removed, so that the body is seen lying
-in the left half of the shell. From the rudimentary head of the Lepas
-there issues a long, fleshy stalk (curving upwards in our drawing); by
-means of it the Barnacle crab grows on rocks, ships, etc. On the ventral
-side are six pairs of feet. Every foot is forked and divided into two
-long, curved, or curled "tendrils" furnished with bristles. Above and
-behind the last pair of feet projects the thin cylindrical tail.
-
-Fig. _E c_ represents a parasitic sack-crab (Sacculina purpurea) from
-the order of Root-crabs (Rhizocephala). These parasites, by adaptation
-to a parasitical life, have developed out of Barnacle crabs (Fig. _D
-c_), much in the same way as the fish-lice (_C c_), out of the freely
-swimming Oar-legged crabs (_B c_). However, the suppression, and the
-subsequent degeneration, of all of the organs, has gone much further in
-the present case than in most of the fish-lice. Out of the articulated
-crab, possessing legs, intestine, and eye, and which in an early stage
-as nauplius (_E n_, Plate VIII.), swam about freely, there has developed
-a formless, unsegmented sack, a red sausage, which now only contains
-sexual organs (eggs and sperm) and an intestinal rudiment. The legs and
-the eye have completely disappeared. At the posterior end is the opening
-of the genitals. From the mouth grows a thick bunch of numerous
-tree-shaped and branching root-like fibres. These spread themselves out
-(like the roots of a plant in the ground) in the soft hinder part of the
-body of the hermit-crab (Pagurus), upon which the root-crab lives as a
-parasite, and from which it draws its nourishment. Our drawing (_E c_),
-a copy of Fritz Mueller's, is slightly enlarged, and shows the whole of
-the sausage-shaped sack-crab, with all its root-fibres, when drawn out
-of the body upon which it lives.
-
-Fig. _F c_ is a _shrimp_ (Peneus Muelleri), from the order of _ten-foot_
-crabs (Decapoda), to which our river cray-fish, and its nearest
-relative, the lobster, and the short-tailed shore-crabs also belong.
-This order contains the largest and, gastronomically, the most important
-crabs, and belongs, together with the mouth-legged and split-legged
-crabs, to the legion of the stalk-eyed mailed crabs (Podophthalma). The
-shrimp, as well as the river crab, has in front, on each side below the
-eye, two long feelers (the first much shorter than the second), then
-three jaws, and three jaw-feet, then five very long legs (the three
-fore ones of which, in the Peneus, are furnished with nippers, and the
-third of which is the longest). Finally, on the first five joints of the
-hinder part of the body there are other five pairs of feet. This shrimp,
-which is one of the most highly developed and perfect crabs, originates
-(according to Fritz Mueller's important discovery) out of a nauplius (_F
-n_ Plate VIII.), and consequently proves that the higher Crustacea have
-developed out of the same form as the lower ones, namely, the nauplius.
-(Compare vol. ii. p. 175.)
-
-
-  PLATES XII. AND XIII. (_Between pages 200 and 201, Vol. II._)
-
-_Blood relationship between the Vertebrata and the Invertebrata._
-(Compare vol. ii. pp. 152 and 201.) It is definitely established by
-Kowalewski's important discovery, which was confirmed by Kupffer, that
-the ontogeny of the lowest vertebrate animal--the Lancelet, or
-Amphioxus--agrees in all essential outlines completely with that of the
-invertebrate Sea-squirts, or Ascidiae, from the class of Sea-sacks, or
-Tunicata. On our two plates, the ascidia is marked by _A_, the amphioxus
-by _B_. Plate XIII. represents these two very different animal-forms in
-a _fully developed_ state, as seen from the _left side_, the end of the
-mouth above, the opposite end below. Hence, in both figures the dorsal
-side is to the right, the ventral to the left. Both figures are slightly
-magnified, and the internal organisation of the animals is distinctly
-visible through the transparent skin. The full-grown ascidia (Fig. _A_
-6) grows at the bottom of the ocean, from whence it cannot move, and
-clings to stones and other objects by means of peculiar roots (_w_) like
-a plant. The full-grown amphioxus, on the other hand (Fig. _B_ 6), swims
-about freely like a small fish. The letters on both figures indicate the
-same parts: (_a_) orifice of the mouth; (_b_) orifice of the body, or
-porus abdominalis; (_c_) dorsal rod, or chorda dorsalis; (_d_)
-intestine; (_e_) ovary; (_f_) oviduct (same as the sperm-duct); (_g_)
-spinal marrow; (_h_) heart; (_i_) blind-sac of the intestine; (_k_)
-gill basket (respiratory cavity); (_l_) cavity of the body; (_m_)
-muscles; (_n_) testicle (in the ascidia united with the ovary into a
-hermaphrodite gland); (_o_) anus; (_p_) genital orifice; (_q_)
-well-developed embryos in the body cavity of the ascidia; (_r_) rays of
-the dorsal fin of the amphioxus; (_s_) tail-fin of the amphioxus; (_w_)
-roots of the ascidia.
-
-Plate XII. shows the _Ontogenesis_, or the individual development of the
-_Ascidia_ (_A_) and the _Amphioxus_ (_B_) in five different stages
-(1-5). Fig. 1 is the egg, a simple cell like the egg of man and all
-other animals (Fig. _A_ 1 the egg of the ascidia, Fig. _B_ 1 the egg of
-the amphioxus). The actual cell-substance, or the protoplasm of the
-egg-cell (_z_), the so-called yolk, is surrounded by a covering
-(cell-membrane, or yolk-membrane), and encloses a globular cell-kernel,
-or nucleus (_y_), the latter, again, contains a kernel-body, or
-nucleolus (_x_); when the egg begins to develop, the egg-cell first
-subdivides into two cells. By another sub-division there arise four
-cells (Fig. _A_ 2, _B_ 2), and out of these, by repeated sub-division,
-eight cells (vol. i. p. 190, Fig. 4 _C_, _D_). By fluid gathering in the
-interior these form a globular bladder bounded by a layer of cells. On
-one spot of its surface the bladder is turned inwards in the form of a
-pocket (Fig. _A_ 4, _B_ 4). This depression is the beginning of the
-intestine, the cavity (_d_ 1) of which opens externally by the
-provisional larval-mouth (_d_ 4). The body-wall, which is at the same
-time the stomach-wall, now consists of two layers of cells--the
-germ-layers. The globular larva (Gastrula), now grows in length. Fig.
-_A_ 5 represents the larva of the ascidia, Fig. _B_ 5 that of the
-amphioxus, as seen from the left side in a somewhat more advanced state
-of development. The orifice of the intestine (_d_ 1) has closed. The
-dorsal side of the intestine (_d_ 2) is concave, the ventral side (_d_
-3) convex. Above the intestinal tube, on its dorsal side, the neural
-tube, the beginning of the spinal marrow, is being formed, its cavity
-still opens externally in front (_g_ 2). Between the spinal marrow and
-the intestine has arisen the spinal rod, or chorda dorsalis (Notochord)
-(_c_), the axis of the inner skeleton. In the larva of the ascidia this
-rod (_c_) proceeds along the long rudder-tail, a larval organ, which is
-cast off in later transformation. Yet there still exist some very small
-ascidiae (Appendicularia) which do not become transformed and attached,
-but which through life swim about freely in the sea by means of their
-rudder-tail.
-
-The ontogenetic facts which are systematically represented on Plate XII.
-and which were first discovered in 1867, deserve the greatest attention,
-and, indeed, cannot be too highly estimated. They fill up the gap which,
-according to the opinion of older zoologists existed between the
-vertebrate and the so-called "invertebrate" animals. This gap was
-universally regarded as so important and so undeniable, that even
-eminent zoologists, who were not disinclined to adopt the theory of
-descent, saw in this gap one of the chief obstacles against it. Now that
-the ontogeny of the amphioxus and the ascidia has set this obstacle
-completely aside, we are for the first time enabled to trace the
-pedigree of man beyond the amphioxus into the many-branching tribe of
-"invertebrate" worms, from which all the other higher animal tribes have
-originated.
-
-If our speculative philosophers, instead of occupying themselves with
-castles in the air, were to give their thoughts for some years to the
-facts represented on Plates XII. and XIII., as well as to those on
-Plates II. and III., they would gain a foundation for true
-philosophy--for the knowledge of the universe firmly based on
-experience--which would be sure to influence all regions of thought.
-These facts of ontogenesis are the indestructible foundations upon which
-the monistic philosophy of future times will erect its imperishable
-system.
-
-
-  PLATE XIV. (_Between pages 206 and 207, Vol. II._)
-
-_Monophyletic, or One-rooted Pedigree of the Vertebrate Animal tribe_,
-representing the hypothesis of the common derivation of all vertebrate
-animals, and the historical development of their different classes
-during the palaeontological periods of the earth's history. (Compare
-Chapter XX. vol. ii. p. 192.) The horizontal lines indicate the periods
-(mentioned in vol. ii. p. 14) of the organic history of the earth during
-which the deposition of the strata containing fossils took place. The
-vertical lines separate the classes and sub-classes of vertebrata from
-one another. The tree-shaped and branching lines, by their greater or
-lesser number and thickness, indicate the approximate degree of
-development, variety, and perfection, which each class probably attained
-in each geological period. In those classes which, on account of the
-soft nature of their bodies, could not leave any fossil remains (which
-is especially the case with Prochordata, Acrania, Monorrhina, and
-Dipneusta) the course of development is hypothetically suggested on the
-ground of arguments derived from the three records of
-creation--comparative anatomy, ontogeny, and palaeontology. The most
-important starting-points for the hypothetical completion of the
-palaeontological gaps are here, as in all cases, furnished by the
-_fundamental law of biogeny_, which asserts the inner _causal-nexus
-existing between ontogeny and phylogeny_. (Compare vol. i. p. 310, and
-vol. ii. p. 200; also Plates VIII.-XIII.) In all cases we have to regard
-the individual development (determined by the laws of Inheritance but
-modified by the laws of Adaptation) as short and quick repetitions of
-the palaeontological development of the tribe. This proposition is the
-"ceterum censeo" of our theory of development.
-
-The statements of the first appearance, or the period of the origin of
-the individual classes and sub-classes of vertebrate animals (apart from
-the hypothetical filling in mentioned just now), are taken as strictly
-as possible from palaeontological facts. It must, however, be observed,
-that in reality the origin of most of the groups probably took place one
-or two periods earlier than fossils now indicate. In this I agree with
-Huxley's views; but on Plates V. and XIV. I have disregarded this
-consideration in order not to go too far from palaeontological facts.
-
-The numbers signify as follows (compare also Chapter XX. and vol. ii.
-pp. 204, 206):--1. Animal Monera; 2. Animal Amoebae; 3. Community of
-Amoebae (Synamoebae); 4. Ciliated Infusoria without mouths; 5. Ciliated
-Infusoria with mouths; 6. Gliding worms (Turbellaria); 7. Sea-sacks
-(Tunicata); 8. Lancelet (Amphioxus); 9. Hag (Myxinoida); 10. Lamprey
-(Petromyzontia); 11. Unknown forms of transition from single-nostriled
-animals to primaeval fishes; 12. Silurian primaeval fish (Onchus, etc.);
-13. Living primaeval fishes (sharks, rays, Chimaerae); 14. Most ancient
-(Silurian) enamelled fishes (Pteraspis); 15. Turtle fishes (Pamphracti);
-16. Sturgeons (Sturiones); 17. Angular-scaled enamelled fishes
-(Rhombiferi); 18. Bony pike (Lepidosteus); 19. Finny pike (Polypterus);
-20. Hollow-boned fishes (Coeloscolopes); 21. Solid boned fishes
-(Pycnoscolopes); 22. Bald pike (Amia); 23. Primaeval boned fishes
-(Thrissopida); 24. Bony fishes with air passage to the swimming bladder
-(Physostomi); 25. Bony fishes without air passage to the swimming
-bladder (Physoclisti); 26. Unknown forms of transition between primaeval
-fishes and amphibious fishes; 27. Ceratodus; 27_a_. Extinct Ceratodus
-from the Trias; 27_b_. Living Australian Ceratodus; 28. African
-amphibious fishes (Protopterus) and American amphibious fishes
-(Lepidosiren); 29. Unknown forms of transition between primaeval fishes
-and amphibia; 30. Enamelled heads (Ganocephala); 31. Labyrinth toothed
-(Labyrinthodonta); 32. Blind burrowers (Caeciliae); 33. Gilled amphibia
-(Sozobranchia); 34. Tailed amphibia (Sozura); 35. Frog amphibia (Anura);
-36. Dichthacantha (Proterosaurus); 37. Unknown forms of transition
-between Amphibia and Protamnia; 38. Protamnia (common primary form of
-all Amnion animals); 39. Primary mammals (Promammalia); 40. Primaeval
-reptiles (Proreptilia); 41. (Thecodontia); 42. Primaeval dragons
-(Simosauria); 43. Serpent dragons (Plesiosauria); 44. Fish dragons
-(Ichthyosauria); 45. Teleosauria (Amphicoela); 46. Steneosauria
-(Opisthocoela); 47. Alligators and Crocodiles (Prosthocoela); 48.
-Carnivorous Dinosauria (Harpagosauria); 49. Herbivorous Dinosauria
-(Therosauria); 50. Maestricht lizards (Mosasauria); 51. Common primary
-form of Serpents (Ophidia); 52. Dog-toothed beaked lizards (Cynodontia);
-53. Toothless beaked lizards (Cryptodontia); 54. Long-tailed flying
-lizards (Rhamphorhynchi); 55. Short-tailed flying lizards
-(Pterodactyli); 56. Land tortoises (Chersita); 57. Birds--reptiles
-(Tocornithes), transition form between reptiles and birds; 58. Primaeval
-griffin (Archaeopteryx); 59. Water beaked-animal (Ornithorhynchus); 60.
-Land beaked-animal (Echidna); 61. Unknown forms of transition between
-Cloacals and Marsupials; 62. Unknown forms of transition between
-Marsupials and Placentals; 63. Tuft Placentals (Villiplacentalia); 64.
-Girdle Placentals (Zonoplacentalia); 65. Disc Placentals
-(Discoplacentalia); 66. Man (Homo pithecogenes, by Linnaeus erroneously
-called, Homo sapiens.)
-
-
-  PLATE XV. (_After page 369, Vol. II._)
-
-_Hypothetical Sketch of the Monophyletic Origin and the Diffusion of the
-Twelve Species of Men from Lemuria over the earth._ The _hypothesis_
-here geographically sketched of course only claims an entirely
-_provisional value_, as in the present imperfect state of our
-anthropological knowledge it is simply intended to show how the
-distribution of the human species, from a single primaeval home, may be
-_approximately_ indicated. The probable primaeval home, or "Paradise," is
-here assumed to be _Lemuria_, a tropical continent at present lying
-below the level of the Indian Ocean, the former existence of which in
-the tertiary period seems very probable from numerous facts in animal
-and vegetable geography. (Compare vol. i. p. 361, and vol. ii. p. 315.)
-But it is also very possible that the hypothetical "cradle of the human
-race" lay further to the east (in Hindostan or Further India), or
-further to the west (in eastern Africa). Future investigations,
-especially in comparative anthropology and palaeontology, will, it is to
-be hoped, enable us to determine the probable position of the primaeval
-home of man more definitely than it is possible to do at present.
-
-If in opposition to our monophyletic hypothesis, the polyphyletic
-hypothesis--which maintains the origin of the different human species
-from several different species of anthropoid ape--be preferred and
-adopted, then, from among the many possible hypotheses which arise, the
-one deserving most confidence seems to be that which assumes a double
-pithecoid root for the human race namely, an Asiatic and an African
-root. For it is a very remarkable fact, that the African man-like apes
-(gorilla and chimpanzee) are characterized by a distinctly long-headed,
-or dolichocephalous, form of skull, like the human species peculiar to
-Africa (Hottentots, Caffres, Negroes, Nubians). On the other hand, the
-Asiatic man-like apes (especially the small and large orang), by their
-distinct, short-headed, or brachycephalous, form of skull agree with
-human species especially characteristic of Asia (Mongols and Malays).
-Hence, one might be tempted to derive the latter (the Asiatic man-like
-apes and primaeval men) from a common form of brachycephalous ape, and
-the former (the African man-like apes and primaeval men) from a common
-dolichocephalous form of ape.
-
-In any case, tropical Africa and southern Asia (and between them
-Lemuria, which formerly connected them) are those portions of the earth
-which deserve the first consideration in the discussion as to the
-primaeval home of the human race; America and Australia are, on the other
-hand, entirely excluded from it. Even Europe (which is in fact but a
-western peninsula of Asia) is scarcely of any importance in regard to
-the "Paradise question."
-
-It is self-evident that the migrations of the different human species
-from their primaeval home, and their geographical distribution, could on
-our Plate XV. be indicated only in a very general way, and in the
-roughest lines. The numerous migrations of the many branches and tribes
-in all directions, as well as the very important re-migrations, had to
-be entirely disregarded. In order to make these latter in some degree
-clear, our knowledge would, in the first place, need to be much more
-complete, and secondly, we should have to make use of an atlas with a
-number of plates showing the various migrations. Our Plate XV. claims no
-more than to indicate, in a very general way, the approximate
-geographical dispersion of the twelve human species as it existed in the
-fifteenth century (before the general diffusion of the Indo-Germanic
-race), and as it can be sketched out approximately, so as to harmonize
-with our hypothesis of descent. The geographical barriers to diffusion
-(mountains, deserts, rivers, straits, etc.), have not been taken into
-consideration in this general sketch of migration, because, in earlier
-periods of the earth's history, they were quite different in size and
-form from what they are to-day. The gradual transmutation of catarrhine
-apes into pithecoid men probably took place in the tertiary period in
-the hypothetical Lemuria, and the boundaries and forms of the present
-continents and oceans must then have been completely different from what
-they are now. Moreover, the mighty influence of the ice period is of
-great importance in the question of the migration and diffusion of the
-human species, although it as yet cannot be more accurately defined in
-detail. I here, therefore, as in my other hypotheses of development,
-expressly guard myself against any dogmatic interpretation; they are
-nothing but _first attempts_.
-
-
-
-
-INDEX.
-
-  A
-
-  ABYSSINIANS, ii. 323, 330
-
-  Acalephae, ii. 141
-
-  Acoelomi, ii. 148, 151
-
-  Acrania, ii. 196, 198, 200, 204
-
-  Acyttaria, ii. 51, 62
-
-  Adaptation, i. 90, 156, 219
-
-  ---- actual, i. 225, 231
-
-  ---- correlative, i. 241
-
-  ---- cumulative, i. 233
-
-  ---- direct, i. 225, 231
-
-  ---- divergent, i. 247
-
-  ---- indirect, i. 224, 227
-
-  ---- individual, i. 228
-
-  ---- irregular, i. 229
-
-  ---- monstrous, i. 229
-
-  ---- potential, i. 224, 227
-
-  ---- sexual, i. 230
-
-  ---- universal, i. 231
-
-  ---- unlimited, i. 249
-
-  Agassiz, Louis, i. 61
-
-  Agassiz's conception of the universe, i. 65
-
-  ---- essay on classification, i. 61
-
-  ---- history of creation, i. 63
-
-  ---- history of development, i. 64
-
-  ---- idea of species, i. 65
-
-  Albuminous bodies, i. 331
-
-  Algae, ii. 81, 82, 83
-
-  Alluvial system, ii. 15
-
-  Altaians, ii. 309, 317
-
-  Alternation of generations, i. 206
-
-  Americans, ii. 309, 318
-
-  Amnion animals, ii. 204, 219
-
-  Amniota, ii. 204, 219
-
-  Amoebae, ii. 53, 279
-
-  Amoeboidea, ii. 53
-
-  Amphibia, ii. 209, 216
-
-  Amphioxus, ii. 198, 285
-
-  Amphirrhina, ii. 203, 205
-
-  Anamnionata, ii. 204
-
-  Animal Plants, ii. 144
-
-  Angiospermae, ii. 83, 111
-
-  Annelida, ii. 133, 149, 151
-
-  Anorgana, i. 5, 328
-
-  Anorganology, i. 6
-
-  Anthozoa, ii. 143
-
-  Anthropocentric conception of the universe, i. 38
-
-  Anthropoides, ii. 270, 275, 292
-
-  Anthropolithic period, ii. 15, 17
-
-  Anthropology, i. 7
-
-  Anthropomorphism, i. 18, 66
-
-  Ape-like men, ii. 293, 300
-
-  Apes, ii. 241, 268, 270
-
-  Arabians, ii. 323, 330
-
-  Arachnida, ii. 180, 182
-
-  Archelminthes, ii. 148
-
-  Archezoa, ii. 132, 134
-
-  Archigony, i. 183, 338
-
-  Archilithic period, ii. 8, 14
-
-  Arians, ii. 323, 331
-
-  Aristotle, i. 55, 76
-
-  Arthropoda, ii. 132
-
-  Articulata, ii. 119
-
-  Ascidia, ii. 152, 200
-
-  Ascones, ii. 141
-
-  Asterida, ii. 164, 166
-
-  Atavism, i. 207
-
-  Australians, ii. 308, 314
-
-  Autogeny, i. 339
-
-
-  B
-
-  BAeR, CARL ERNST, i. 109
-
-  ---- doctrine of filiation, i. 109
-
-  ---- theory of development, i. 294
-
-  ---- types of animals, i. 53; ii. 119
-
-  Basques, ii. 322
-
-  Bathybius, i. 184, 344; ii. 53
-
-  Batrachians, ii. 204
-
-  Bats, ii. 240, 261
-
-  Beaked mammals, ii. 233, 239
-
-  ---- reptiles, ii. 224, 226
-
-  Belief, i. 9; ii. 335
-
-  Berbers, ii. 323, 330
-
-  Biogenesis, fundamental law of, i. 309; ii. 33
-
-  Biology, i. 6
-
-  Birds, ii. 204, 226
-
-  Brachiopoda, ii. 157
-
-  Brain, bladder of, in man, i. 304
-
-  ---- development of, i. 303
-
-  Bruno Giordano, i. 22, 70
-
-  Bryozoa, ii. 150, 152
-
-  Buch, Leopold, i. 107
-
-  Buechner, Louis, i. 110
-
-  Buds, formation of, i. 192
-
-
-  C
-
-  CAFFRES, ii. 312, 333
-
-  Calcispongiae, ii. 140, 144
-
-  Cambrian system, ii. 9, 15
-
-  Carbon, i. 330, 335
-
-  ---- theory of, i. 335
-
-  Carboniferous system, ii. 11, 15
-
-  Carus Victor, i. 110
-
-  Catallacta, i. 51, 59
-
-  Catarrhini, ii. 270, 272
-
-  Caucasians, ii. 309, 321
-
-  Causa finalis, i. 34, 75
-
-  Causal conception of the universe, i. 18, 74
-
-  Cells, i. 187, 346
-
-  ---- formation of, i. 347
-
-  ---- theory of, i. 346
-
-  Cell-kernel, i. 188
-
-  ---- membrane, i. 188
-
-  ---- substance, i. 186
-
-  Caenolithic period, ii. 14, 16
-
-  Cephalopoda, ii. 160, 162
-
-  Chamisso, Adalbert, i. 206
-
-  Change of climate, i. 363
-
-  Chelophora, ii. 240, 257
-
-  Chinese, ii. 309, 317
-
-  Chorology, i. 351
-
-  Cloacal animals, ii. 234, 239
-
-  Cochlides, ii. 159, 160
-
-  Coelenterata, ii. 136, 144
-
-  Coelomati, ii. 148, 151
-
-  Coniferae, ii. 82, 110
-
-  Constructive forces, i. 90, 253, 337
-
-  Copernicus, i. 39
-
-  Corals, ii. 142, 144
-
-  Coreo-Japanese, ii. 309, 317
-
-  Cormophytes, ii. 80
-
-  Correlation of parts, i. 218
-
-  Cosmogeny, i. 321
-
-  Cosmological gas theory, i. 323
-
-  Crabs, ii. 174, 176
-
-  Craniota, ii. 198, 204
-
-  Creation, centres of, i. 352
-
-  ---- the, i. 8
-
-  Creator, the, i. 64, 70
-
-  Cretaceous system, ii. 12, 15
-
-  Crinoides, ii. 166, 171
-
-  Crocodiles, ii. 223, 224
-
-  Crustacea, ii. 173, 176
-
-  Cryptogamia, ii. 80, 82
-
-  Ctenophera, ii. 142, 144
-
-  Cultivated plants, i. 137
-
-  Curly-haired men, ii. 310, 333
-
-  Cuttles, ii. 160, 162
-
-  Cuvier, George, i. 50
-
-  Cuvier's dispute with Geoffroy, i. 88
-
-  ---- history of creation, i. 59
-
-  ---- palaeontology, i. 54
-
-  ---- idea of species, i. 50
-
-  ---- theory of cataclysms, i. 58
-
-  ---- theory of revolutions, i. 58
-
-  ---- types of animals, i. 53; ii. 118
-
-  Cycadeae, ii. 82, 110
-
-  Cyclostoma, ii. 202, 204
-
-  Cytod, i. 346
-
-
-  D
-
-  DARWIN, CHARLES, i. 131
-
-  Darwinism, i. 149
-
-  Darwin's life, i. 132
-
-  ---- travels, i. 132
-
-  ---- theory of corals, i. 133
-
-  ---- theory of selection, i. 150
-
-  ---- study of pigeons, i. 141
-
-  Darwin, Erasmus, i. 118
-
-  Deciduata, ii. 240, 255
-
-  Deduction, i. 85; ii. 357
-
-  Democritus, i. 22
-
-  Devonian system, ii. 11, 14
-
-  Diatomeae, ii. 51, 60
-
-  Dicotylae, ii. 82, 112
-
-  Didelphia, ii. 239
-
-  Differentiation, i. 270, 283
-
-  Diluvial system, ii. 15
-
-  Dipneusta, ii. 204, 212
-
-  Divergence, i. 270
-
-  Division of labour, i. 247
-
-  Domestic animals, i. 137
-
-  Dragons, ii. 225
-
-  Dravidas, ii. 308, 319
-
-  Dualistic conception of the universe, i. 20, 75
-
-  Dysteleology, i. 15; ii. 353
-
-
-  E
-
-  ECHINIDA, ii. 166, 171
-
-  Echinoderma, ii. 163, 166
-
-  Edentata, ii. 240, 254
-
-  Egg Animals, ii. 132, 134
-
-  Eggs, i. 190, 198
-
-  Egg of man, i. 190, 297; ii. 279
-
-  Egg, cleavage of the, i. 190, 299; ii. 280
-
-  Egyptians, ii. 323, 330
-
-  Elephants, ii. 257
-
-  Empiricism, i. 79; ii. 349
-
-  Eocene system, ii. 15, 16
-
-  Ethiopians, ii. 323, 330
-
-  Explanation of phenomena, i. 29
-
-
-  F
-
-  FERNS, ii. 82, 101
-
-  Fibrous plants, ii. 82
-
-  Final cause, i. 22
-
-  Fins, ii. 309, 317
-
-  Fishes, ii. 206, 208
-
-  Flagellata, ii. 51, 57
-
-  Flat-nosed apes, ii. 270, 272
-
-  Flat worms, ii. 148, 150
-
-  Flint cells, ii. 51, 60
-
-  Flowering plants, ii. 82, 108
-
-  Flower animals, ii. 143
-
-  Flowerless plants, ii. 80, 82
-
-  Flying animals, ii. 240, 261
-
-  Freke, i. 119
-
-  Fulatians, ii. 308, 320
-
-  Fungi, ii. 82
-
-
-  G
-
-  GANOID FISH, ii. 208, 210
-
-  Gastraea, ii. 127, 128, 281
-
-  Gastrula, ii. 126, 127
-
-  Gegenbaur, i. 312; ii. 179, 193
-
-  Gemmation, i. 192
-
-  Generation, i. 209
-
-  Genus, i. 41
-
-  Geocentric conception of the universe, i. 38
-
-  Geoffroy S. Hilaire, i. 86, 116
-
-  Germans, ii. 323, 331
-
-  Germ buds, formation of, i. 193
-
-  ---- cells, formation of, i. 194
-
-  Gibbon, ii. 270, 275
-
-  Gilled insects, ii. 174, 176
-
-  Gill-arches in man, i. 307
-
-  God, conception of, i. 70
-
-  Goethe, Wolfgang, i. 80
-
-  Goethe's conception of nature, i. 22
-
-  ---- discovery of mid-jaw bone, i. 84
-
-  ---- formative tendency i. 91, 253
-
-  ---- idea of God, i. 71
-
-  ---- investigations in nature, i. 81
-
-  ---- materialism, i. 23
-
-  ---- metamorphosis, i. 90
-
-  ---- metamorphosis of plants, i. 82
-
-  ---- philosophy of nature, i. 81
-
-  ---- theory of development, i. 92
-
-  ---- vertebrae of skull, i. 83
-
-  Genochoristus, i. 196
-
-  Gonochorism, i. 196
-
-  Gorilla, ii. 270
-
-  Grant, i. 119
-
-  Greeks, ii. 323, 331
-
-  Gregarinae, ii. 133, 134
-
-  Gynmosperms, ii. 82, 109
-
-
-  H
-
-  HALISAURIA, ii. 204, 214
-
-  Hare-rabbit, i. 148, 275
-
-  Heliozoa, ii. 64
-
-  Herbert, i. 119
-
-  Heredity, i. 176
-
-  Hermaphrodites, i. 196
-
-  Herschel's cosmogeny, i. 321
-
-  Holothuriae, ii. 166, 172
-
-  Hoofed animals, ii. 249, 252
-
-  Hooker, i. 119
-
-  Hottentots, ii. 311, 333
-
-  Human races, ii. 296, 305, 308
-
-  ---- soul, ii. 361
-
-  Huxley, i. 119, 145; ii. 268
-
-  Hybridism, i. 145, 210, 275
-
-  Hydromedusae, ii. 143, 145
-
-
-  I
-
-  ICE PERIOD, i. 367; ii. 17
-
-  Indecidua, ii. 241, 249
-
-  Individual development, ii. 293
-
-  Indo-Chinese, ii. 309, 317
-
-  Indo-Germanic, ii. 323, 331
-
-  Induction, i. 85; ii. 357
-
-  Infusoria, ii. 132, 135
-
-  Inheritance, abridged, i. 212
-
-  Inheritance, acquired, i. 213
-
-  ---- adapted, i. 213
-
-  ---- amphigonous, i. 210
-
-  ---- conservative, i. 204
-
-  ---- constituted, i. 216
-
-  ---- contemporaneous, i. 217
-
-  ---- continuous, i. 205
-
-  ---- established, i. 216
-
-  ---- homochronous, i. 217
-
-  ---- interrupted, i. 205
-
-  ---- latent, i. 205
-
-  ---- mixed, i. 210
-
-  ---- progressive, i. 213
-
-  ---- sexual, i. 209
-
-  ---- simplified, i. 212
-
-  ---- uninterrupted, i. 205
-
-  ---- laws of, i. 204
-
-  Inophyta, ii. 82, 93
-
-  Insects, ii. 184
-
-  Insectivora, ii. 241, 259
-
-  Instinct, ii. 343
-
-  Invertebrata, ii. 118, 195
-
-  Iranians, ii. 323, 331
-
-
-  J
-
-  JAPANESE, ii. 309, 317
-
-  Jews, ii. 323, 330
-
-  Jura system, ii. 12, 14
-
-
-  K
-
-  KANT, IMMANUEL, i. 101, 321
-
-  Kant's Criticism of the faculty of judgment, i. 105
-
-  ---- mechanisms, i. 37, 102
-
-  ---- philosophy of nature, i. 101
-
-  ---- theory of descent, i. 103
-
-  ---- theory of development, i. 321
-
-  ---- theory of the formation of the universe, i. 101
-
-  Knowledge, a posteriori, i. 31; ii. 345
-
-  ---- a priori, i. 31; ii. 344
-
-
-  L
-
-  LABYRINTHULEAE, ii. 51
-
-  Lacertilia, ii. 223
-
-  Lamarck, Jean, i. 111
-
-  Lamarck's anthropology, i. 115; ii. 264
-
-  ---- philosophy of nature, i. 112
-
-  ---- theory of descent, i. 113
-
-  Lamarckism, i. 150
-
-  Lamellibranchia, ii. 158, 160
-
-  Lancelet, ii. 198, 204, 285
-
-  Laplace's cosmogeny, i. 321
-
-  Laurentian system, ii. 9, 14
-
-  Lemuria, i. 361; ii. 326
-
-  Leonardo da Vinci, i. 56
-
-  Leptocardia, ii. 196, 204
-
-  Leucones, ii. 141
-
-  Linnaeus, Charles, i. 39
-
-  Linnaeus' classification of animals, ii. 118
-
-  ---- classification of plants, ii. 78
-
-  ---- designation of species, i. 41
-
-  ---- history of creation, i. 44
-
-  ---- system, i. 40
-
-  Lubbock, Sir John, ii. 298
-
-  Lyell, Charles, i. 126
-
-  Lyell's history of creation, i. 128
-
-
-  M
-
-  MAGYARS, ii. 309, 316
-
-  Malays, ii. 308, 315
-
-  Malthus' theory of population, i. 161
-
-  Mammalia, ii. 231, 239
-
-  Man-apes, ii. 271, 275, 292
-
-  Marsupials, ii. 236, 239, 290
-
-  Matagenesis, i. 206
-
-  Materialism, i. 35
-
-  Matter, i. 22; ii. 360
-
-  Mechanical causes, i. 34, 74
-
-  Mechanical conception of the universe, i. 17, 74
-
-  Mechanism, i. 37, 102
-
-  Mediterranese, ii. 308, 321
-
-  Medusae, ii. 143, 144
-
-  Mesolithic period, ii. 14, 20
-
-  Metamorphosis of the earth's strata, ii. 25
-
-  Metamorphosis, i. 90
-
-  Migration, laws of, i. 373
-
-  ---- of organisms, i. 354
-
-  ---- of the human species, ii. 325
-
-  ---- theory of, i. 367
-
-  Mind, i. 22; ii. 360
-
-  ---- development of the, ii. 344, 360
-
-  Miocene period, ii. 15, 16
-
-  Miracles, i. 22
-
-  Molluscs, ii. 155, 160
-
-  Monera, i. 184, 343; ii. 52, 278
-
-  Mongols, ii. 308, 316
-
-  Monism, i. 34
-
-  Monistic conception of the universe, i. 20, 74
-
-  Monocottylae, ii. 82, 112
-
-  Monoglottonic, ii. 327, 333
-
-  Monogony, i. 183
-
-  Monophylites, ii. 44
-
-  Monophyletic hypothesis of descent, ii. 44
-
-  Monorrhina, ii. 203, 204
-
-  Monosporogonia, i. 194
-
-  Monotrema, ii. 234, 239
-
-  Morphology, i. 21
-
-  Morula, ii. 125, 127
-
-  Moses' history of creation, i. 37
-
-  Moss animals, ii. 150, 152
-
-  Mosses, ii. 82, 97
-
-  Mueller, Fritz, i. 49, 73; ii. 174
-
-  Mueller, Johannes, i. 312; ii. 203
-
-  Muscinae, ii. 82, 99
-
-  Mussels, ii. 159, 160
-
-  Myriapoda, ii. 182, 184
-
-  Myxomycetes, ii. 51, 60
-
-
-  N
-
-  NATURAL PHILOSOPHY, i. 78
-
-  Negroes, ii. 309, 313, 333
-
-  Nemathelminthes, ii. 149, 150
-
-  Newton, i. 25, 106
-
-  Non-amnionate, ii. 204, 209
-
-  Nubians, ii. 308, 320
-
-
-  O
-
-  OECOLOGY, ii. 354
-
-  Oken, Lorenz, i. 95
-
-  Oken's history of development, i. 293
-
-  ---- philosophy of nature, i. 96
-
-  ---- theory of infusoria, i. 97
-
-  ---- ---- protoplasm, i. 97
-
-  Olynthus, ii. 141
-
-  Ontogenesis, i. 293
-
-  Ontogeny, i. 10; ii. 33
-
-  Orang, ii. 271, 275
-
-  Organisms, i. 5, 328
-
-  Organs, i. 5
-
-  Origin of language, ii. 302, 327
-
-  Osseous fishes, ii. 208, 211
-
-  Ovularia, ii. 132, 134
-
-
-  P
-
-  PACHYCARDIA, ii. 201
-
-  Palaeolithic period, ii. 11, 14
-
-  Palaeontology, i. 54
-
-  Palissy, i. 56
-
-  Palm ferns, ii. 82, 110
-
-  Pander, Christian, i. 294
-
-  Papuans, ii. 310, 333
-
-  Paradise, ii. 325
-
-  Parallelism of development, i. 313
-
-  Parthenogenesis, i. 197
-
-  Pedigree of amphibia, ii. 209
-
-  ---- anamnia, ii. 209
-
-  ---- apes, ii. 270
-
-  Permean system, ii. 11, 14
-
-  Petrifactions, i. 54
-
-  Phanerogama, ii. 80, 82, 108
-
-  Philosophy, i. 79; ii. 350
-
-  Phylogeny, i. 10; ii. 33
-
-  Phylum, ii. 42
-
-  Physiology, i. 21
-
-  Pithecoid, theory, ii. 356
-
-  Placentalia, ii. 240, 244
-
-  Planula, ii. 126, 135, 281
-
-  Planaea, ii. 125, 127
-
-  Planaeada, ii. 280
-
-  Plasma, i. 185, 330
-
-  Plasmogony, i. 339
-
-  Plastids, i. 347
-
-  Plastids, theory of, i. 347
-
-  Platyelminthes, ii. 148, 150
-
-  Platyrrhini, ii. 270, 272
-
-  Pleistocene system, ii. 15
-
-  Pliocene system, ii. 15, 16
-
-  Polar man, ii. 308, 317
-
-  Polyglottal, ii. 327, 333
-
-  Polynesians, ii. 308, 315
-
-  Polyphyletic theory of descent, ii. 45
-
-  Polyphylites, ii. 45, 303
-
-  Polyps, ii. 142
-
-  Polyp jellies, ii. 143, 144
-
-  Polysporogonia, i. 193
-
-  Population, number of, ii. 333
-
-  Porifera, ii. 139, 144
-
-  Primary mammals, ii. 239, 290
-
-  Primary period, ii. 11, 14
-
-  Primaeval algae, ii. 82, 84
-
-  ---- animals, ii. 131, 132
-
-  ---- history of man, ii. 298
-
-  ---- men, ii. 325
-
-  Primordial period, ii. 9, 14
-
-  Prochordata, ii. 278
-
-  Progenitors of man, ii. 279, 295
-
-  Progress, i. 277, 283
-
-  Promammalia, ii. 233, 239
-
-  Propagation, i. 183
-
-  ---- amphigonic, i. 195
-
-  ---- monogonic, i. 183
-
-  ---- non-sexual, i. 183
-
-  Propagation, sexual, i. 195
-
-  ---- virginal, i. 197
-
-  Protamnia, ii. 289, 295
-
-  Protamoebae, ii. 52
-
-  Prothallophytes, ii. 80, 97
-
-  Prothallus plants, ii. 80, 97
-
-  Protista, ii. 48
-
-  Protophyta, ii. 82, 85
-
-  Protoplasma, i. 185, 330
-
-  Protoplasts, ii. 51, 53
-
-  Protozoa, ii. 121, 131, 132
-
-  Purpose in nature, i. 19
-
-  Purposelessness in nature, i. 20
-
-
-  R
-
-  RADIATA, ii. 120
-
-  Radiolaria, i. 333, 371; ii. 65
-
-  Rapacious animals, ii. 240, 260
-
-  Recent system, ii. 15
-
-  Reptiles, ii. 222, 224
-
-  Rhizopoda, ii. 51, 61
-
-  Ringed worms, ii. 149, 150
-
-  Rodentia, ii. 241, 257
-
-  Romans, ii. 323, 331
-
-  Rotatoria, ii. 149, 150
-
-  Rotifera, ii. 150, 152
-
-  Round worms, ii. 149, 150
-
-  Rudimentary eyes, i. 13
-
-  ---- gristle, i. 12
-
-  ---- legs, i. 14
-
-  ---- lungs, i. 289
-
-  ---- mammary glands, i. 290
-
-  ---- muscles, i. 12
-
-  ---- nictitating membrane, i. 13
-
-  ---- organs, i. 12
-
-  ---- pistils, i. 15
-
-  ---- stamens, i. 15
-
-  ---- tails, i. 289
-
-  ---- teeth, i. 12
-
-  ---- wings, i. 287
-
-
-  S
-
-  SACK WORMS, ii. 283, 295
-
-  Sauria, ii. 222
-
-  Schaaffhausen, i. 110
-
-  Schleicher, August, i. 108; ii. 301
-
-  Schleiden, J. M., i. 109
-
-  Science, i. 9; ii. 335
-
-  Scolecida, ii. 283, 295
-
-  Sea stars, ii. 164, 166
-
-  ---- cucumbers, ii. 166, 171
-
-  Sea dragons, ii. 204
-
-  ---- lilies, ii. 166, 177
-
-  ---- nettles, ii. 141, 144
-
-  ---- urchins, ii. 166, 171
-
-  Secondary period, ii. 14, 20
-
-  Selection aesthetic, i. 268
-
-  ---- artificial, i. 152, 170, 254
-
-  ---- homochromic, i. 263
-
-  ---- medical, i. 173
-
-  ---- military, i. 171
-
-  ---- musical, i. 267
-
-  ---- natural, i. 168, 255
-
-  ---- psychical, i. 269
-
-  ---- sexual, i. 265
-
-  ---- Spartan, i. 170
-
-  Self-division, i. 191
-
-  Semites, ii. 322, 330
-
-  Serpents, ii. 223
-
-  Sexes, separation of, i. 244
-
-  Sexual characters, i. 209, 265
-
-  Silurian system, ii. 8, 14
-
-  Slavonians, ii. 323, 331
-
-  Snails, ii. 159, 160
-
-  Soul, the, i. 71; ii. 343, 362
-
-  Species, i. 41, 273, 304, 311
-
-  Specific development, i. 311
-
-  Spencer, Herbert, i. 119; ii. 367
-
-  Sperma, i. 197
-
-  Spiders, i. 180, 182
-
-  Spirobranchia, ii. 157, 160
-
-  Sponges, ii. 139, 144
-
-  Spores, formation of, i. 194
-
-  Stemmed plants, ii. 280
-
-  Straight-haired men, ii. 309, 314
-
-  Struggle for life, i. 161, 252
-
-  Synamoeba, ii. 125, 280
-
-  Systematic development, i. 313
-
-  System of animals, ii. 132
-
-  ---- apes, ii. 270
-
-  ---- Arabians, ii. 330
-
-  ---- arachnida, ii. 182
-
-  ---- Arians, ii. 331
-
-  ---- arthropoda, ii. 132
-
-  ---- articulata, ii. 177, 183
-
-  ---- catarrhini, ii. 270
-
-  ---- coelenterata, ii. 144
-
-  ---- crustacea, ii. 176
-
-  ---- didelphia, ii. 239
-
-  ---- echinoderma, ii. 166
-
-  ---- Egyptians, ii. 330
-
-  ---- fishes, ii. 208
-
-  ---- formations, ii. 15
-
-  ---- Germans, ii. 331
-
-  ---- gilled Insects, ii. 177
-
-  ---- Graeco-Romans, ii. 331
-
-  ---- Hamites, ii. 330
-
-  ---- hoofed animals, ii. 252
-
-  ---- human ancestors, ii. 295
-
-  ---- human races, ii. 308
-
-  ---- human species, ii. 308, 309
-
-  ---- Indians, ii. 331
-
-  ---- Indo-Germani, ii. 331
-
-  ---- insects, ii. 182
-
-  ---- mammalia, ii. 239
-
-  ---- mankind, ii. 295
-
-  ---- marsupials, ii. 239
-
-  ---- men and apes, ii. 271
-
-  ---- molluscs, ii. 160
-
-  ---- monodelphia, ii. 241
-
-  ---- organisms, ii. 74, 75
-
-  ---- placentalia, ii. 240
-
-  ---- plants, ii. 82
-
-  ---- platyrrhini, ii. 270
-
-  ---- protista, ii. 51
-
-  ---- reptiles, ii. 224
-
-  ---- Semites, ii. 330
-
-  ---- Slavonians, ii. 331
-
-  ---- spiders, ii. 182
-
-  ---- star fishes, ii. 167
-
-  ---- strata of the earth, ii. 15
-
-  ---- tracheata, ii. 182
-
-  ---- ungulata, ii. 252
-
-  ---- vegetable kingdom, ii. 83
-
-  ---- vertebrata, ii. 204
-
-  ---- worms, ii. 150
-
-  ---- zoophytes, ii. 144
-
-
-  T
-
-  TAIL OF MAN, i. 289, 308
-
-  Tangles, ii. 61, 82
-
-  Tartars, ii. 209, 317
-
-  Teleology, i. 100, 291
-
-  Teleostei, ii. 208, 211
-
-  Teleological conception of the universe, i. 20, 75
-
-  Tertiary period, ii. 14, 16
-
-  Thallophytes, ii. 80, 82
-
-  Thickness of the earth's crust, ii. 19
-
-  Thought, ii. 364
-
-  Thread plants, ii. 82, 93
-
-  Tocogony, i. 183
-
-  Tortoises, ii. 225
-
-  Tracheata, ii. 182
-
-  Transition forms, ii. 338
-
-  Transmutation, theory of, i. 4
-
-  Treviranus, i. 92
-
-  Trias system, ii. 12, 14
-
-  Tuft-haired men, ii. 307, 309
-
-  Tunicata, ii. 152, 200
-
-  Turbellaria, ii. 283
-
-  Turks, ii. 309, 316
-
-
-  U
-
-  UNGER, FRANZ, i. 109
-
-  Ungulata, ii. 249, 252
-
-  Unity in nature, i. 22, 338
-
-  Uralians, ii. 309, 317
-
-
-  V
-
-  Variability, i. 220
-
-  Variation, i. 219
-
-  Varieties, i. 276
-
-  Vertebrata, ii. 195, 205
-
-  Vital force, i. 22, 334
-
-  Vitalistic conception of the universe, i. 18
-
-
-  W
-
-  Wagner, Andreas, i. 138
-
-  Wagner, Moritz, i. 369
-
-  Wallace, Alfred, i. 135
-
-  Wallace's chorology, i. 361, 373
-
-  ---- theory of selection, i. 136
-
-  Well's theory of selection, i. 150
-
-  Whales, ii. 240, 251
-
-  Will, freedom of the, i. 113, 237, 364
-
-  Wolff's theory of development, i. 293
-
-  Woolly-haired men, ii. 307, 309
-
-  Worms, ii. 147, 150
-
-
-  Z
-
-  ZOOPHYTES, ii. 136, 144
-
-
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