RAY RRMA SS MAY Asp WOO WAY ON ROK» WIS, IS SMO MOO\QY SS Le YZ es \ \. SY WS \ Ss IN Rn MWY YH EON WA Oy SY »Y \ \ \\ . NOON? ‘ Mongols (7) with four Races: 12% Semitic, 12°Basque, . : 1? Indochinese, 7°Koreojapanese, . , . 7° High Asians, 7! Urlens. Arctic Circle est: SS R North Pacific Ocean i el ee Tropic of Cancer Epcaety ieee, 8 64 sar Madagascar Tropic of Capricorn | onetl Indian Ocean x Ws s oditerre Dein | Polar | M s ‘ lo _ , Hypothetical Sketch aL =< Ce atin Yage = emi he 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, MA, FRR, FELLOW OF EXETER COLLEGE, OXFORD. IN TWO VOLUMES. VOL. It. NEW YORK: D. APPLETON AND COMPANY, 1, 3, anD 5 BOND STREET. 1880. A sense subtime 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 though’, 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. WorbDsworrs, SZA2Y 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.—Palzontological 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.—Smalli Extent of Paleontological 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 see eee eos eee ese eee eee eee eee 1 be XY = = 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 Monophy- letic 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 Primeval Beings. — Hight Classes of the Protista Kingdom: Monera, Amcebex, or Protoplaste ; Whip-swimmers, or Flagellata; ated-balls, or Cili Catallacta; Labyrinth-streamers, or Labyrinth- 1V CONTENTS. PAGE ulez ; Flint-cells, or Diatomez; 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 oes vee eee ose eve eve 8 CHAPTER XVII. PEDIGREE AND HISTORY OF THE VEGETABLE KINGDOM, The Natural System of the Vegetable Kingdom.—Division of the Vege- table Kingdom into Six Branches and Eighteen Classes.—The Flowerless Plants (Cryptogamia).—Sub-kingdom of the Thallus Plants.—The Tangles, or Algze (Primary Alge, Green Alge, Brown Alge, Red Algz.)—The Thread-plants, or Inophytes (Lichens and Fungi).—Sub-kingdom of the Prothallus Plants.—The Mosses, or Muscine (Water-mosses, Liverworts, Leaf-mosses, Bog-mosses).— The Ferns, or Filicinee (Leaf-ferns, Bamboo-ferns, Water-ferns, Scale-ferns).—Sub-kingdom of Flowering Plants (Phanerogamia).— The Gymnosperms, or Plants with Naked Seeds (Palm-ferns = Cycadex ; Pines = Coniferae.)—The Angiosperms, or Plants with Enclosed Seeds.—Monocotyle.—Dicotyle.—Cup-blossoms (Ape- talze).—Star-blossoms (Diapetalz).—Bell-blossoms (Gamopetale) 77 CHAPTER XVIII. PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM. I. ANIMAL-PLANTS AND Worms. The Natural System of the Animal Kingdom.—Linneus and Lamarck’s Systems.—The Four Types of Bir 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 Primeval 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—Primzval Animals (Monera, Amcebe, Synameebe), Gregarines, Infusoria, Planeades, and Gas- treades (Planula and Gastrula).—Tribe of Zoophytes.—Spongiz (Mucous Sponges, Fibrous Sponges, Calcareous Sponges).—Sea Nettles, or eae Meee Hood ret eee -jellies).—Tribe of Worms ee ee ae wot ees Tris CONTENTS. V CHAPTER XIX. PAGE PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM. II. Mouiuusca, Srar-FisHes, AND ARTICULATED ANIMALS. Tribe of Molluses.—Four Classes of Molluscs: Lamp-shells (Spirobran- chia); Mussels (Lamellibranchia) ; Snails (Cochlides); Cuttle-fish (Cephalopoda).—Tribe of Star-fishes, or Echinoderma.—Their Deri- vation 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 ... eee eee oe LOt CHAPTER XX. PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM. III. VERTEBRATE ANIMALS. The Records of the Creation of Vertebrate Animals (Comparative Anatomy, Embryology, and Palzontology).—The Natural System of Vertebrate Animals.—The Four Classes of Vertebrate Animals, according to Linnzeus 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 Am- phioxus and Ascidie.—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 Ani- mals, devoid of Amnion.—Fishes (Primeval 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, Croco- diles, Tortoises, Flying Reptiles, Dragons, Beaked Reptiles).—Birds (Feather-tailed, Fan-tailed, Bush-tailed.) ... Ay wae tea E92 Vl CONTENTS. CHAPTER XXI. PeVIGREE AND HISTORY OF THE ANIMAL KINGDOM. IV. Mammats. PAGE The System of Mammals according to Linnzus and Blainville-—Three Sub-classes of Mammals (Ornithodelphia, Didelphia, Monodelphia). —Ornithodelphia, or Monotrema.—Beaked Animals (Ornithostoma). —Didelphia, or Marsupials.—Herbivorous and Carnivorous Marsu- pials.—Monodelphia, or Placentalia (Placental Animals).—Meaning of the Placenta.—Tuft Placentalia.—Girdle Placentalia.—Dise Pla- centalia.—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 eee eee ooo eos eee eae eee eos 2al CHAPTER XXII. ORIGIN AND PEDIGREE OF MAN. The Application of the Theory of Descent to Man.—Its Immense Im- portance 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 ... we eee eve eee eve 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, CONTENTS. Vil P 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.—Primeval Home of Man (South Asia, or Lemuria).—Nature of Primeval Men.—Number of Primeval Languages (Monoglottists and Polyglottists).—Divergence and Migration of the Human Race.—Geographical Distribution of the Human Species ove eee eee eee eee eee eee CHAPTER XXIV. OBJECTIONS AGAINST, AND PROOFS OF THE TRUTH THE THEORY OF DESCENT. Objections to the Doctrine of Filiation Objections of Faith and Reason.—Immeasurable Length of the Geological Periods.—Transi- ion 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 4 priori Knowledge from Knowledge 4 posteriori—The Knowledge requisite for the Correct Understanding of the Doctrine of Filiation.—Neces- sary Interaction between Empiricism and Philosophy.—Proofs of the Theory of Descent.—Inner Causal-Connection between all the Bio- logical 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 Deduc- tion.—Gradual Development of the Human Mind.—Body and Mind. —Human Soul and Animal Soul.—A Glance at the Future sat List OF WORKS REFERRED TO IN THE TEXT ,,, aa wat APPENDIX (Explanation of the Plates) se eee vee at InpEx see see toe eee eae ane eee see eee AGE 296 OF, 834 LIST OF ILLUSTRATIONS. — OH PLATES. XV.—Hypothetical Sketch of the Monophyletic Origin of Man Frontispiece IV.—Hand of Nine different Mammals... sof ... Lo face page 34 V.—Single-Stemmed, or Monophyletic, Pedigree of the Vegetable Kingdom EE = 112 VI.—Historical Growth of the Six (rie Stems of Kuilndta = 122 Vil.—Animal Plants, or Zoophytes eis cn vee 2 140 Tits i —First G ti VIili.—Star Fishes—First Generation a Between pp. 170,171 IX.—Star Fishes—Second Generation X.—Nauplius-Youth-Form of Six Crab Fish XI.—Adult-Form of the same Six Crab Fish j es XII.—Ascidia and Amphioxus XTL—Ascidia and Amphioxus j XIV.—Single, or Monophyletic, Pedigree of Back-boned Animals ooo soo sone iwe, ie, LO face page 222 >: Jee vee eee eee ” 201, 202 FIGURES. 8.—Protamceba Primitiva ... sini biieen Liem Cree oo «52 9.—Bathybius Heckelii ... Siac: Haale Gos coe) ene 10.—Amceba Spheerococcus oe eee on oo a aay ia ae 11.—Euglena Striata ... ace ove cee nse one ose acs: fae 12.—Magosphera Planula .., au — ose ove eee ee «85 13:—Labyrinthula Macrocystis ...ece --:see (‘sue +<2see wae wavs ae 14.—Navicula Hippocampus vee ove eee cos eee oe «OO 15.—Physarum Albipes a aa ae eee eee vee rin) 16.—Cyrtidosphera Echinoides .,.. eee oop eee eee oo. ae 17.—Caulerpa Denticulata ... = Wee eee eee oes ots 18.—Euastrum Rota .., = és ove oes as ove oe 88 19.—Fucus Vesiculosus (egg of) ... on ove ove ate as on 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.—Palzontological 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 Strataonly 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 Paleontological 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 2 THE HISTORY OF CREATION, with much the same interest as antiquarians and ethno- graphers 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 organ- isms, 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 under- standing 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 genealo- gical 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 CONSTRUCTION OF THE PEDIGREE. 3 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. 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 descend- ants 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 palzeontolo- gical development of all organic tribes with the embryological development of individuals, and with the systematic de- velopment of groups. In order to accomplish our task we shall first have to direct our attention to paleontology, or the science of petri- factions. For if the Theory of Descent is really true, if the petrified remains of formerly living animals and plants really proceed from the extinct primeval ancestors and progenitors of the present organisms, then, without any- 4 ¥ THE HISTORY OF CREATION, thing 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, Wwe may now at once examine the conditions and circum- stances 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 exceed- ingly important transformation of the rigid inorganic crust of the earth. The water began that extremely import- ant 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 LEVELLING ACTION OF WATER. 5 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 mechani- cally washes away the loose particles. In flowing down from mountains water carries their débris into the plains, or deposits it as mud in stagnant lakes. Thus it con- tinually 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 débris 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 con- tinual 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 théusands 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 6 THE HISTORY OF CREATION. 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 characterize 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 lime- stone, 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 GEOLOGICAL SYSTEMS AND PERIODS. 7 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 oonditions of de- velopment 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 corres~ ponding 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 forma- tions; 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 38 THE HISTORY OF CREATION. 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 these sections again into subordi- nate 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 dis- tinctly 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 paleontological 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 desig- nate the five epochs, on the one hand by the names of the croups 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 (Algze) and skull-less Vertebrates; the second, or primary epoch, that of the Ferns and Fishes; the third, or THE GREAT ROCK-SYSTEMS. 9 secondary epoch, that of Pine Forests and Reptiles; the jourth, 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 perdods 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 ter- restrial 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 Cam- brian, 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 re- TO THE HISTORY OF CREATION. quired 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 unrecognizable. Only in one portion of the Cambrian and Silurian strata have petri- factions been preserved in a recognizable condition and in large quantities. The most ancient of all distinctly pre- served petrifactions has been found in the lowest Lauren- tian strata (in the Ottawa formation), which I shall after- wards have to speak of as the “Canadian Life’s-dawn” (Eozoon canadense). Although only by far the smaller portion of the primor- dial or archilithic petrifactions are preserved to us in a recognizable condition, still they possess the value of inestim- able 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 im- mense 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 Algz, living in water. In the warm primeval sea, these constituted the forests of the primordial 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 PRIMARY EPOCH. II 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 Acrunia 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 palzolithic or paleeozoic 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 dura- tion, 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 tovether 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 primeval 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 arti- EZ THE HISTORY OF CREATION. culated 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, ete.). 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 paleeozoic 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 Phylopteridz), as well as bamboo ferns (Calamophytze) and scaled ferns (Lepidophyte). These ferns, which grew on land, formed the chief part of the dense palzeolithic 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 palzontological history of development is formed by the secondary epoch, or the era of Pine Forests, which is also called the mesolithie 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 de- posited during this pericd 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 pri- mary group, and amounts as a whole only to about 15,000 THE SECONDARY EPOCH. 13 feet. The secondary epoch can accordingly in all prob- ability 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 verte- brate 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 gigan- tic Labyrinthodonts, in the sea the wonderful sea-dragons, or Halisaurii, swam about, and the first fish with bones were associated with the many primeval fishes (Sharks) and enamelled fish (Ganoids) of the earlier times; but the very variously developed kinds of reptiles formed the predomi- nating 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 Gymmnosperms, 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 Coniferw, and the palm-ferns, or Cycadee—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. The fourth main division of the organic history of the I4 THE HISTORY OF CREATION, SURVEY Of the Paleontological Periods, or of the Greater Divisions of the Organic History of the Earth. I. First Epoch: Arcumiruic Era. Primordial Epoch. (Era of Skull-less Animals and Forests of Tangles.) 1. Older Primordial Period or Laurentian Period. 2. Middle Primordial Period 9» Cambrian Period. 3. Later Primordial Period » Silurian Period. II. Second Epoch: PaumouitHic 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. Ill. Third Epoch: Mesouiruic Era. Secondary Epoch. (Era of Reptiles and Pine Forests.) 7. Older Secondary Period or Trias Period. 8. Middle Secondary Period 7 Jura Period. 9. Later Secondary Period » Chalk Period. IV. Fourth Epoch: Cxnouitnic 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. Fijth Epoch: AnturopotitHic 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.) | STRATA CONTAINING PETRIFACTIONS, SURVEY Of the Paleontological Formations, or those Strata of the Earth’s Crust containing Petrifactions. 15 Rock- ee a Systems: Formations. 5 spain. Some Md V. cali XIV. Recent 36. Present Upper alluvial (Alluvium) 35. Recent Lower alluvial Anthropolithic XIII. Pleistocene § 34, Post glacial | Upper diluvial (Anthropozoic) - (Diluvium) 33. Glacial Lower diluvial groups of strata IV. Tertiary XII. Pliocene ; 32. Arvernian Upper pliocene =. (Late tertiary) 31. Sub-Appenine | Lower pliocene XI. Miocene } 30. Falunian Upper miocene Caenolithic (New tertiary) 29. Limburgian | Lower miocene (Czenozoic) 28. Gypsum Upper eocene groups of strata ee ee 27. Nummulitic | Mid eocene ( ertiary) 26. London clay | Lower eocene 25. White chalk | Upper cretaceous 24. Green sand Mid cretaceous / IX. Cretaceous 23. Neocomian Lower cretaceous III. Secondary 22. Wealden The KentishWeald Got, 21. Portlandian | Upper oolite iene. Saed 20. Oxfordian Mid oolite Mesolithic r 19. Bath Lower oolite (Mesozoic) 18. Lias Lias formation groups of strata 17. Keuper Upper trias Vil, Trias 16. Muschelkalk | Mid trias 15. Bunter sand | Lower trias - 14. Zechstein Upper Permian II. Primary ee { 13. Lower Permian Ati 12. Carboniferous V. Carbonic sandstone Upper carbonic Paleolithic (coal) 11. Carboniferous (Palzeozoic) limestone Lower carbonic groupsof strataf IV. Devonian 10. Pilton Upper Devonian ahi red sand. 9. Ilfracombe Mid Devonian stone) 8. Linton Lower Devonian 7. Ludlow Upper Silurian ‘ = eta il. Silurian 6. Llandovery Mid Silurian 5. Llandeilo Lower Silurian , 4. Potsdam Upper Cambrian re I. Cambrian ; 3. Longmynd Lower Cambrian groups of strata ¥’ Taint 2. Labrador Upper Laurentian 1. Ottawa Lower Laurentian 16 THE HISTORY OF CREATION. - 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 cznolithic or czenozoic 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 J/ammals 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 con- sists of the two classes of single-seed-lobed plants, or Mono- cotyledons, 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 THE ERA OF MAN, 17 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 comi- cal 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 stratifica- tion. The neptunice 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 remark- able 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 exer- cised on the geographical and topographical distribution of organisms has already been explained in the preceding chap- 19 18 THE HISTORY OF CREATION. ter (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 primeval 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 im- measurable length of the periods which have passed from the beginning of organic life on the earth down to the origin of the human race. LAPSE OF TIME, 19 The tabular view given on page 15 shows the succession of the palzontological 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 correspond- ing eras of the larger and smaller paleontological periods, and in a reversed succession, from the most ancient Lauren- tian 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 palzolithic; 15,000 to the secondary, or mesolithic; and finally only 3,000 to the tertiary, or cenolithic 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 anaverage 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 organie history of the earth—that is, from the beginning of life on the earth 20 THE HISTORY OF CREATION. down to the present day—ainto 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 e ° » 53.6 II. Paleolithic, or primary period . ° ° e 32.1 III. Mesolithic, or secondary period . : « 118 IV. Cenolithic, or tertiary period . . . 2.3 VY. Anthropolithic, or quaternary period : » O5 Total ... 100.0 According to this, the length of the archilithie 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 earries with it a consider- GEOLOGICAL INTER-REGNA, . 2I able 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 com- parisons 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 paleontological difference—which is per- ceived 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 intermedi- ate 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 ques- tion under water, that there occurred a new deposit of earth. As, in the mean time, the inorganic and organic con- ditions on this part had undergone a considerable transform- ation, the newly-formed layer of mud was necessarily com- 22 THE HISTORY OF CREATION. IV. Tertiary Group of Strata, 3000 feet. —— ______l Eocene, Miocene, Pliocene. IX. Chalk System. TII. Mesolithic Group of Strata. Deposits of the Vill. Jura System. Secondary Epoch, about 75.000 fk | A ae nn aos Vil. Trias System. IL Paleolithic Group of Strata. VI. Permian System. a oe V. Coal System. Primary Epoch, about 42,000 feet. IV. Devonian System. ce I III. Silurian System, about 22,000 feet. I. Archilithic Group of Strata. II. Cambrian System, about 18,000 feet. Deposits of the Primordial Epoch, about 70,000 feet. I. Laurentian System, about 30,000 feet. RISING AND SINKING OF LAND. 23 posed of different earthy constituents and enclosed different petrifactions. The striking differences which so frequently occur be- tween 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, some- times to a few inches, or at most a few feet. But if this action continues uninterruptedly throughout hundreds of t.ousands 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 distri- bution of organisms. (Compare vol.i. p. 350.) But to form a judgment of our paleontological records of creation it is ex- tremely 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 24 THE HISTORY OF CREATION. 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 im- mediately 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 enclose. 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 de- pression, 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 pre- served. It is evident, however, that these periods of elevation, which have passed without leaving any trace be- hind 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 RECORDS DESTROYED BY FIRE. s the new territory, in the struggle for life, abundant oppor- tunity of developing themselves peculiarly, and of forming new species. This 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 nume- rous 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 pale- ontological 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 com- pletely 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 26 THE HISTORY OF CREATION, 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 petrifac- tions known, the EKozoon 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 sur- face 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 investi- gated ; but of the larger portion of Asia, the most extensive of all continents, we know almost nothing ; of Africa almost 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 palzontologically 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 petrifac- tions. A hint that this will be the case is given by the remarkable petrifactions found in those parts of Africa and FOSSILS ARE ONLY THE HARD PARTS. 27 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 paleeontological investiga- tions, and that the greater part of the petrifactions which have lain there from primeval 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 palzontological record must always present an immense gap. But, in addition to these, there exists another series of difficulties in the way of paleontology 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 cir- cumstances favourable to their becoming petrified, or dis- tinctly impressing their external form upon the hardening mud. Now, it must be borne in mind that large classes of 28 THE HISTORY OF CREATION. organisms, as for example the Medusz, 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 import- ant 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 in- habitants 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 com: paratively solid, and in the second place very easily separates FOOTPRINTS OF UNKNOWN ANIMALS, 29 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 remark- able 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 (Mar- supials) 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 jaw- bone 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.* 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 palzontological 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 * With the exception of asingle specimen of the bones of a foot, preserved in the cabinet of Amherst College.—E. R. L. 30 THE HISTORY OF CREATION, has been of the very greatest importance for the phylogeny of the whole class of birds. Atl 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 palzontological records must necessarily be exceedingly im- perfect, 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 con- nect 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 main- tain 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 GRADUATED SERIES OF FOSSIL SPECIES. 31 even now they cause the greatest perplexity and occasion endless disputes among systematic palzeontologists 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 Wiirtemburg, 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 Jike manner, among very many other fossil species (for example, many ammonites, terebratulz, sea urchins, lily encrinites, etc.) there are such masses of con- necting 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 signifi- cance 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 archzology and philology. Just as it has 32 THE HISTORY OF CREATION. become possible by means of these two most ancient in- scriptions 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 :— “T 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 en- tombed 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 paleontological 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 ONTOGENY. 33 fossils, other records of the history of the origin of organ- isms, 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 develop- ment of the organic individual (embryology and metamor- phology). 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 paleontological 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 qu'ck repetition, or recapitulation, of Phylogeny, determined by the laws of In- heritance 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. i 6, 110, 300.) It is true that the sketch which the ontogeny of or- ganisms 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 tue 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 34 THE HISTORY OF CREATION, for the knowledge of the earliest paleontological 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 funda- mental 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 im- mensely important fact, established by ontogeny, that the simple increase, the formation of cell-aggregates and the differentiation of those cells, produced the infinitely mani- fold forms of multicellular organisms. Thus ontogeny helps us over many and large gaps in paleontology. To the invaluable records of creation furnished by paleontology 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. 8), his nearest relations. Butit will Mammals. Hand of N + s co) a) “4 as vo A éesse sc. o E Haeckel del. es Man, 2. Gorilla , 3. Orang, 4. Dog, 5. Seal 9. Duck - bull, 6.Porpoise, 7. Bat, 8. Mole, F vv A) en ; ADA | 1 / ibe m4 | AD | ( ‘ Welle i us | CRen inna? THE FORE FEET OF MAMMALS, 35 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 incon- ceivable 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 mam- mals, 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. 30 THE HISTORY OF CREATION, 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 Primzyal Beings.—Eight Classes of the Protista Kingdom—Monera, Amcebe, or Protoplastze.— Whip-swimmers, or Flagellata.—Ciliated-balls, or Catallacta.—Labyrinth. streamers, or Labyrinthulez.— Flint-cells, or Diatomeze.—Mucons-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 palzeonto- logical 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 CONSTRUCTION OF THE PEDIGREE, 37 employing the empirical results of embryology, palzon- tology, 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, paleontological, and anatomical knowledge, to establish a probable scheme of the genealogical relation- ships 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 de- scended 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 tran- sitional 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. 38 THE HISTORY OF CREATION, Four years ago I set up a number of hypothetical genea- logies for the larger grcups of organisms in the systematic introduction to my General History of Development (Gen. Morph. vol. i), 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 cer- tainly in this case much easier to blame than to produce something better, and what best proves the immense diffi- culty 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 re- placed 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 tuis kind our genealogical know- ledge, in the course of time, will slowly advance and approach more and more towards perfection, although it can with certainty be foreseen that we shall never arrive ata MONERA, THE BASE OF THE PEDIGREE. 39 complete pedigree. We lack, and shall ever lack, the indis- pensable paleontological foundations. The most ancient records will ever remain sealed to us, for reasons which have been previously mentioned. The most ancient organ- isms 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 paleontological 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 paleontological 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 com- posed 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 40 THE HISTORY OF CREATION. 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 com- pletely than all petrifactions could do as to the original paleontological 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 paleontological 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 primeval 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 ege-cell of plants. When the upponents 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 incredib:e 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 PEDIGREE OF MONERA. 41 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 primzeval “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 “ primzeval cell.” But where did those few “original cells,” or the one primeval cell, come from? For the answer to this funda- mental genealogical question we must return to the theory of plastids and the hypothesis of spontaneous generaticn 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 primeeval creatures of the simplest kind conceivable, like the still living Protamcebe, Protomyxe, ete. (vol. 1. 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 fulfils the two organic fundamental functions of nutrition and propagation —could have directly arisen out of inorganic matter by auto- geny 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 20 42 THE HISTORY OF CREATION, covering (membrane, or skin) was formed round simple eytods (without kernel), as well as round naked cells (containing a kernel). By these two processes of separation in the simpie primeval 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 king- doms, 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 genera- tion? 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 ease, and that it is in reality a matter of very subor- linate 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 his- THE GREAT STEMS OF THE PEDIGREE, 43 torical 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 an] in the vegetable kingdoms, he only assumes either four or five. In the animal kingdom these tribes would essen- trally coincide with those four, five, or six main divisions which zoologists, since Bar and Cuvier, have distinguished as “main forms, general plans, branches, or sub-kingdoms” of the animal kingdom. (Compare vol.1. p. 53.) Bar 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, never- theless 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 :—1l. Flowering plants (Phanerogamia) ; 2. Ferns (Filicine); 3. Mosses (Muscine); 4. Lichens (Lichenes) ; 5. Fungi (Fungi); and 6. Water-weeds (Alyz). 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 44 THE HISTORY OF CREATION, 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 king- doms, 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 examin- ation 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 primeval 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 cau- tiously 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 compara- tive 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 differ- ent 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 MANY OR ONE ANCESTRAL STOCKS ? 45 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 com- position of that mucous albuminous combination. But these subtle and complicated differences of mixture of the infinitely manifold combinations of albumen are not appre- ciable 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 cach 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, 46 THE HISTORY OF CREATION. 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 sup- position, 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 tdea that several different races of men have arisen, independently of one another, out of several different species of ape. Without here expressing our opimion 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 primzeval 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 croup 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 THE PROTISTA, 47 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 struc- ture, 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 the Protista are so small that they can scarcely, if at all, be perceived with the naked eye. Hence the ma- jority 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 zoolo- gists 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 contra- 48 THE HISTORY OF CREATION, dictions are not altogether caused by our imperfect know- ledge 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 in- vestigator 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 cha- racteristic 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 king- dom 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 defini- tion 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, p. 191-238. In my Monograph of the Monera,® 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 :— THE KINGDOM PROTISTA. 49 1, The still living Monera ; 2. The Amceboidea, or Protoplasts ; 3. The Whip-swimmers, or Flagellata; 4. The Flimmer-balls, or Catallacta; 5. The Tram-weavers, or Labyrinthulee ; 6. The Flint-cells, or Diatomez; 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 pro- yressive 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 Labyrinthulez, 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 or animal and vegetable properties, the indifferent and un- certain 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 50 THE HISTORY OF CREATION. another, or with the lowest animals on the one hand, and with the lowest plants on the other hand. It is not improb- able 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 poly- phyletic 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 offshoots 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. (Com- pare 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. 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 stil living Monera ? We know nothing of their palzontological 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 consti- tutes 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 unreason- PROTISTA. SYSTEMATIC SURVEY Of the Larger and Smaller Groups of the Kingdom Protista. 5! Cla f igen Orders Anam the Proticta Oe tue Families Othe se Ba Kingdom. a cai Classes. as an example. 1. Gymnomonera Protogenes 1. MoneRS Monera 2. Lepomonera Protomyxa 1. Gymnamcebza Ameeba 2. PrororLasts Ameceboida 2. Lepamcebze Arcella 3. Gregarinze Monocystis 3. WHIP-SwIM- t 1. Nudiflagellata Euglena Flagellata MERS pee 2. Cilioflagellata Peridinium 4. FLIMMER-BALLS Catallacta 1. Catallacta Magosphera 5. TRAM-WEAVERS Labyrinthules 1. Labyrinthules Labyrinthula 1. Striata Navicula 6. FLINT-CELLS Diatomea ars ——- 3. Areolata Coscinodiscus 1. Physarezo AXthalium 2. Stemoniteze Stemonitis 7. SuimE-moutps Myxomycetes 4 Rix 3. Trichiacez Arcyria 4. Lycogalez Reticularia : 1. Monothalamia Gromia I. Acyttaria ' 8. RAy-sTREAM- 2. Polythalamia Nummulina ERS, OR RHI- 2 1. Heli je ince Desi: Il. Heliozoa . Hell0z0a ctinospheerium (Root-feet.) eco 1. Monocyttaria Cyrtidosphera Ill. Radiolaria i 2. Polycyttaria Collosphzera 52 THE HISTORY OF CREATION. able to assign them to the animal as it would be to assign them to the vegetable kingdom. Im any case we shall for the present be acting more cautiously and criticaliy if we comprise the still living Monera—whose number and dis- tribution is probably very great—as a special and inde- pendent 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 Fic. 8.—Protamceba primitiva, @ 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 com- pleted, and each now represents an independent individual. 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 (Protamceba, Proto- genes, Protomyxa, etc.) in my Monograph of the Monera,” 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- BATHYBIUS, 53 water Protamceba (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 pro- toplasm and reticular mucus (vol. 1. p. 344). Fic. 9.— Bathybius Hec- kelii, the “creature of primeval 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 disco- liths 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 Amebe of the present day, and the organisms most closely connected with them, Arcellide and Gregarine, which we here unite as a second class of Protista under the name of Amceboidea (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 unlerstood 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 Algz (spores and eggs) exist for a ionger or shorter time in water in the 54 THE HISTORY OF CREATION, form of naked cells with a kernel, which canno% be distin- guished at all from the naked eggs of many animals (for example, those of the Siphonophorous Medusze). (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 Amceba 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 Ameeba shows in stretching out and drawing in its changing pro- cesses, is a general vital property of the organic plasma of all animal as well as of all vegetable plastids) Whena freely moving Amceba, which perpetually changes its form, passes into a state of rest, it draws itseli together into the form of a globule, and surrounds itself with a secreted mem- brane. It can then be as little distinguished from an anima] exg as from a simple globular vegetable cell (Hig. 10 4). Fre. 10.—Amceba spheerococcnus, greatly magnified. A fresh-water Ameeba without a contractile vacuole. A. The enclosed Amceba 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). AMCEBOID ORGANISMS. 55 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 amceboid, 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 Protameeba (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 Amoebze have lately been recognized as the early stages of development of other Protista (especially the Myxomycetie), 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 Amcebe. 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). How- ever, other Amcebze (like the one given in Fig. 10) seem to be independent “good species,” since they propagate them- selves unchanged throughout many generations. Besides the real, or naked, Amcebee (Gymnamcebe), we also find widely difiused in fresh water case-bearing Amcebee (Lep- amoebee), 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 Ameoebe (Gregarinz), which, adapting themselves to a para- sitic life, have surrounded their plasma-body with a delicate closed membrane. The simple naked Amcebee are, next to the Monera, the 56 THE HISTORY OF CREATION. most important of all organisms to the whole science of biology, and especially to general genealogy. For it is evident that the Amocebz originally arose out of simple Monera (Protamcebze), by the important process of segre- gation 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, tucy formed the first vegetable cells, while others, remaining naked, developed into the first ageregates 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 Amcebz 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 im- portant 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 ‘heir soft bodies, as do the Amcepe (ig. 10 B) and the THE FLAGELLATA. 57 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). The Whip-swimmers (Flagellata), which we consider as a third class of the kingdom Protista, are of no less doubtful nature than the Amcebee. They often show as close and important relations to the vegetable as to the animal kingdom. Some Ilagellata at an early stage, when freely moving about, cannot be distinguished from real plants, especially from the spores of many Algz; whereas others are directly allied to real animals, namely, to the fringed Fic. L1.—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. Infusoria (Ciliata). The Flagellata are simple y ye cells which live in fresh or salt water, either iid) singly or united in colonies. The characteristic Wepwes part of their body is a very movable simple Vit or compound whip-lke appendage (whip, or Nay 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 Euglenze, immense masses of which frequently make our ponds in spring quite green. 58 THE HISTORY OF CREATION. A very remarkable new form of Protista, which I have named Flimmer-ball (Magosphera), I discovered only three years ago (in September, 1869), on the Norwegian coast (Fig. 12), and have more accurately described in my Fic. 12.—The Norwegian Flim- mer-ball (Magosphera planula) swimming by means of its vibra- tile fringes, as seen from the surface. Biological Studies” (p. 137, Plate V.). Off the island of Gis-oe, near Ber- gen, 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 dis- solved. The individual cells swarmed about independently in the water like fringed Infusoria, or Ciliata. These after- wards sank to the bottom, drew their fringes into their bodies, and gradually changed into the form of creeping Amoebe (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 THE TRAM-WEAVERS, 59 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. The Protista of the fifth class, the Tram-weavers, or Labyrinthulee, 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- Fie, 13.— Labyrinthula macro- cystis (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 reti- form labyrinth which form their “ tramways.” ochre colour, which are sometimes united into a dense mass, sometimes move about in a very peculiar way. They form, in @ manner not yet explained, a retiform frame of en- tangled 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 Labyrinthulez we might consider them as the simplest plants, from their motion as the simplest animals, but in reality they are neither animals nor plants. 60 THE HISTORY OF CREATION, Fic. 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 (Diatomeze), a sixth class of Protista, are perhaps the most closely related to the Labyrinthuleze. These primary crea- tures—which at present are generally con- sidered 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 uni- versally 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 THE SLIME-MOULDS, 61 Fic. 15.—A stalked fruit-body (spore-bladder, filled with spores) of one of the Myxomycetes (Physarum albipes) not much enlarged. 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). How ever, the characteristic cellular threads, or hyphe, 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 Amcebe (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 prob- ably know one of these plasmodia, the Aithalium 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-creepmg Myxomycetes, which live for the most part in damp forests, upon decaying vegetabie 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. The nature of the Iay-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 62 THE HISTORY OF CREATION, 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, Actinosphzerium). 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 Amceboidea, 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-animal- cules, 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 proto- plasm, 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 THE RAY-STREAMERS. 63 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 (Polythal- amia)—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 le 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 shelis of the Polythalamia are wound round one another in a spiral line. The chambers are con- nected 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 cal- careous 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 sccreted 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 64 THE HISTORY OF CREATION. 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 under- stand how this same “ primzval slime”—this same proto- plasm—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 petri- fied condition, belongs to the Polythalamia. This organism is the “ Canadian Life’s-dawn ” (Hozoon 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-animaleules (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, Actinosphzrium THE RAY-STREAMERS. 65 Kichhornii. 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 Cysto- phrys 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 mem- brane. This closed “central capsule,” generally of a glo- bular 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 un- known function, containing grains of starch. Most Radio- Jaria 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), some- times 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 bails. In othev 21 66 THE HISTORY OF CREATION. 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 Fic. 16.—Cyrtidosphera 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. common central point. The skeletons of other Radiolaria again form symmetrical m any-chambered structures, as in the case of the Polythalamia. Perhaps no other group of THE RAY-STREAMERS. 67 organisms develop in the formation of their skeletons such an amount of various fundamental forms, such geometrical recularity, and such elegant architecture. Most of the forms as yet discovered, I have given in the atlas accompanying my Monograph of the Radiolaria.”? Here I shall only give as an example the picture of one of the simplest forms, the Cyrtidosphera 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 (J). 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 com- pletely 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 sells 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 Iittle acquainted with the eight classes of the Protista just mentioned, I shall 68 THE HISTORY OF CREATION. 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, ete. 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 Diatomez 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 sub- stance, 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 tself in their irritability, that is, in the movements and, iother changes which take place in consequence of mechan- PHYSIOLOGY OF PROTISTA, 69 ical, 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 pro- pagation 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 form- ation of buds, the formation of germs, ete. But sexual propagation almost always exists by the side of it, and often regularly alternates with it in succeeding generations (Meta- genesis, vol. i. p. 206). All Protista, on the other hand, pro- pagate 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 chenuical 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 scaffold- ing of the body in most genuine plants, consists of a sub- stance called cellulose, devoid of nitrogen, but secreted by the 7O THE HISTORY OF CREATION. 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 cal- careous 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 cf their body almost always remains at an extremely low stage of development. Very many Pro- tista 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 ina 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 re- mains 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 PRO-MORPHOLOGY OF PROTISTA, 7! 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 “reoular radiate” forms, and an irregular pyramid in the more highly differentiated, so-called “bilaterally symmetri- cal” 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, hexhahedron, octahedron, dodecahedron, icosahedron), ete. 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 palwontological 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, 72 THE HISTORY OF CREATION, 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 offshoots 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 off- sets, 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 primeval 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 dif- ferent Monera must have arisen by spontaneous generation whose differences would depend only upon slight, to us imperceptible, differences in their chemical composition, and COMMON ORIGIN OF PLANTS AND ANIMALS, ca consequently upon differences in their capability of develop- ment. 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, indepen- dently 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 olyphyletic hypotheses is as yet quite impossible, consider- ing 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. Thus, if we assume one entirely independent trunk for 74 THE HISTORY OF CREATION. ik III. Degetable Kingdom Animal Kingdom Plante Animalia EEO Flowering Plants Vertebrate Animals Phanerogamia Vertebrata Articulated Animals Arthropsda Star-fishes Molluscous Animals Ferns Echinoderma Mollusca Filicine ~~ Mosses Muscine Lichens SO Lichenes Worms Vermes Animal-trees Zoophytes —— Fungi Alge Fungi a, Ss —Acuttral nie Brimebval Wlants YBrimabal Creatures Primabal Animals Protophyta Protista Protozoa —S———.,-_—_—" — | | Neutral Monera Animal Monera Vegetable Monera | il Archigonic fAonera (Pieces of Protoplasm which have originated by Spontaneous Generation) POLYPHYLETIC PEDIGREE, 75 II. (i III. — Degetable {rotista Animal Kingdom Kingdom Kingdom Vegetabilia Protista Animalia —— ————— SS a Slime-moulds, or Ray- Mucous Fungi streamers Myzxomycetes Rhizopoda oa — -——" Flint- Flimmer. cells balls Diatome Catallacta ——-—’ ———-—_—" Whip- swimmers Flagellata Tram. ed weavers Labyrin- thulea —_—_——"" ' Ameebee, Brimabal Primeval {lants or Animals Protophyta Protoplasta Protozoa —— —_— Degetable Peutral Animal fAonera felonera LHonera Clg oem t t [aN ed t t t t t E14 Tt a t | t t Ht N.B.—The Lines marked with a + indicate extinct tribes of Protista, which have arisen independently by repeated acts of Spontaneous Generation. 76 THE HISTORY OF CREATION. the vegetable kingdom, and a second for the animal king- dom, 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 primeval by protoplasm, CHAPTER XVIL PEDIGREE AND HISTORY OF THE VEGETABLE KINGDOM. The Natural System of the Vegetable Kingdom.—Division of the Vege- table Kingdom into Six Branches and Eighteen Classes.— The Flowerless Plants (Cryptogamia)—Sub-kingdom of the Thallus Plants.—The Tangles, or Alge (Primary Algze, Green Algz, Brown Algz, Red Algsz.)—The Thread-plants, or Inophytes (Lichens and Fungi.)—Sub-kingdom of the Prothallus Plants——The Mosses, or Muscinze (Water-mosses, Liverworts, Leaf-mosses, Bog-mosses).—The Ferns, or Filicinee (Leaf-ferns, Bamboo-ferns, Water-ferns, Scale- ferns).—Sub-kingdom of Flowering Plants (Phanerogamia).—The Gymnosperms, or Plants with Naked Seeds (Palm-ferns = Cycadez ; Pines = Coniferze.)—The Angiosperms, or Plants with Enclosed Seeds. —Monocotyle.—Dicotyle.—Cup-blossoms (Apetale).—Star-blossoms (Diapetalze).—Bell-blossoms (Gamopetalz). EveErY 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 evi- dence 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 import- ance 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 78 THE HISTORY OF CREATION. 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 promot- ing 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 paleontology, the more surely may we con- sider 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 sroups. These main divisions, or sub-kingdoms, are the same as were distinguished more than a century ago by Charles Linnzus, the founder of systematic natural history, and which he called Cryptogamia, or secretly-blossoming plants, and Phanerogania, or openly-flowering plants. The latter, Linnzeus, 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 tlowerless THE CLASSIFICATION OF PLANTS, 79 plants, which were formerly but little observed, have in con- sequence 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 erghteen classes of the vegetable kingdom can again be naturally grouped in such a manner that we are able to dis- tinguish in all sia main divisions or branches of the vege- table 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, differ- ing very essentially in their internal structure and in their externalform, namely, the Thallus plants and the Prothallus plants. The group of Yhallus plants comprises the two large branches of Tangles, or Algze, 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, ete. 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 recog- nized from the fact that the two morphological fundamental organs of all other plants, stem and leaves, cannot be dis- tinguished in their structure. The complete body of all Algze and of all Thread-plants is a mass composed of simple 80 THE HISTORY OF CREATION, 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 Flowermg 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 Thales Plana | I. Thallus Plants I. Flowerless Plants. (Thallophyta) (Thallophyta) Cryptogania (Cryptog ) B. Prothallus Plants (Prothallophyta) II. Stemmed Plants (Cormophyta) (Phanerogamia) II. Flowering Plants C. Flowering Plants (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 archilithie, 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 asa whole, THE ALG, OR TANGLES, SI amounts to about 70,000 feet. Now, as the thickness of all the more recent superincumbent 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 immeasur- able 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 Algz. 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 Algz, 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 Algze 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 Alo are dis- tinguished as much by size of body as by the perfection and variety of their outer form. At the lowest stage we find 82 THE HISTORY OF CREATION. SYSTEMATIC VIEW Of the Siz Branches and Eighteen Classes of the Vegetable Kingdom. See tadons —, —— pre es Name regetable ‘Singdom. Vegetable Kingdom. | Vegetable Kingdom. Classes. 1. Primeval 1. Archephycee- aleze (Protophyta) 2. Green algze 2. Chlorophycecee 3 (Chloroalgz) ean 3Blants Tangles 3. Brown algx 3. Pheophycee Thallophyta (Fucoidez) 4, Red algze 4. Rhodophycee (Floridez) 5. Lichens 5. Lichenes riven lint 6. Fungi 6. Fungs Inophyta 7.Tangle-mosses 7%. Charobrya (Characeze) 8. Liverworts 8. Thallobrya Hat (Hepaticz) 9. Frondose- 9. Phyllobrya Muscine Boe ESSE, (Frondose) hee 10. Turf-mosses 10. Sphagnobrya IBlants (Sphagnaceze) Prothallophyta 11. Shaft-ferns 11. Calamarie (Calamophy ta) 12. Frondose- 12. Filices ne ferns (Pteridez) Felicine 13. Aquatic ferns 13. Rhizocarpee (Hydropterides) 14. Scale-ferns 14. Selaginee (Lepidophyta) Plants with Pini with 15. Palm-ferns 15. Cycadew pedantaaantet Gymnosperma 16. Pines 16. Conifere Phanerogamia ; “ae ee 17. Plants with 17. Monocotyle Enclosed Seeds one seed lobe Angiosperma 18. Plants with 18. Dicotyle ‘ two seed lobes PEDIGREE OF THE VEGETABLE KINGDOM. 83 Gamopetale (Flowers with corolla) Dialypetale (Star-shaped flowers) Monochlamydee MoNOCOTYLEDONA (Flowers with calyx) (One seed-lobed plants) DICOTYLEDONE (Two seed-lobed plants) Nee seen eg ey CoNIFERE Angiosperme CyvcaDEZ (Pines) (Plants with enclosed seeds) ‘Palm-ferns) GNETACEE ~ ' ly Gymnosperme (Plants with 2s seeds) Phanerogame (Flowering plants) Ptcridew Rhizocarpee (Frondose-ferns) (Water-ferns) Calamarie (Shaft-ferns) Se ee ee eee eee Filicine Frondose Sphagnacee (Ferns) (Leaf-mosses) (Turf-mosses) Selaginee (Scaled-ferns) CHARACES (Tangle-mosses) Hepatice (Liverworts) ea Muscine (Mosses) Fucoidee Floridee (Brown Algze) Lichenes (Red Alga) Chlorophyceee (Lichens) (Green Algze) EE 2 Fungi Inophyta Alge (Tangles) (Thread-plants) a Protophyta (Primzeval Plants) Vegetable Monera 84 THE HISTORY OF CREATION. 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 kingdem. It is possible that a large portion of the coal has been formed out of Algze. If not for these reasons, yet the Algz 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 hypo- thesis of a common origin for all groups of plants is correct. (Compare p. 83.) | Most people living inland can form but a very imperfect idea of this exceedingly interesting branch of the vege- table 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, stag- nant and flowing, are for the most part composed of dif- ferent species of Algz. 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 Algze at the bottom, know how to estimate the importance of the class of Alew. And yet, even these marine Alge-forests of European shores, so rich in forms, give only a faint idea THE CLASSES OF ALG. 85 of the colossal forests of Sargasso in the Atlantic ocean, those immense banks of Algze, 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 Aloz grew in the primeval ocean, probably in dense masses, and what countless genera- tions of these archilithic Aloz 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 Algz. 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 Algze forests of the ocean. Within the branch of the Algze 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 Primeval Alove, or Archephycez, Green Algze, or Chlorophyceze, Brown Algve, or Pheeophycee, and Red Alez, or Rhodophyceee. The first class of Algze, the Primeval Algze (Archephyceee), might also be called primeval 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, 86 THE HISTORY OF CREATION, 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. 1. p. 345.) Even at the present day there exist various most simple forms of Aleze which have devi- ated but little from the original primary plants. Among them are the Algz of the families Codiolacese, Protococ- caceze, Desmidiacez, Palmellaceze, Hydrodictyez, and several others. The remarkable group of Phycochromaceze (Chroocoecaceze and Oscillarineze) might also be comprised among them, unless we prefer to consider them as an in- dependent tribe of the kingdom Protista. The monoplastic Protophyta—that is, those primary Aleve 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 Siphonez, which are of con- siderable size, and strangely “mimic” the forms of higher plants. Many of the Siphoneze attain a size of several feet, and resemble an elegant moss (Bryopsis), or in some eases 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. These curious Siphonez, Vaucherize, and Caulerpze show UNI-CELLULAR ALG. 5 7 lic. 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. 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 88 THE HISTORY OF CREATION. Desnudiacece, of which a species of Euastrum is represented in Fig. 18 as a specimen. Fig. 18.—Enuastrum rota, a single-celled Desmid, much enlarged. The whole of the star-shaped body of this primeval 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 primeval plants, the soft body of which, however, was not capable of being preserved in a fossil state, at one time peopled the Lau- rentian primeeval 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 (Chlorophycee), or Green Alge (Chloroalgze), are the second class, and the most closely allied to the primeval group. Like the majority of the Archephycez, all the Chlorophycez are coloured green, and COLOSSAL ALGA, 89 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 Algze, most of the Alge of fresh water, the common water hair-weeds, or Conferve, the green slime- balls, or Gloeosphzerze, the bright green water-lettuce, or Ulva, which resembles a very thin and long lettuce leaf, _and also numerous small microscopic alge, 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 Algz in the composition and differentiation of their body. As the green Alge, like the primeval Algze, mostly possess a very soft body, they are but rarely capable of being petrified. However, it can scarcely be doubted that this class of Algze —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 (Pheo- phyceze), or Black Algw (Fucoides), the branch of the Algeze 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 Algz, which are at the same time the longest of all plants, namely, the colossal giant Algze, amongst which the Macrocystis pyrifera, on the coast of California, attains a length of 400 feet. Also, among our indigenous Ale, the largest 22 eTe) THE HISTORY OF CREATION, 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 Algz). 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 Meduse—that they might easily be mistaken one for another (Fig. 19). Fic. 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 Fucoideze, or Brown Algz, which during the pri- mordial period, to a great extent constituted the characteristic alea-forests of that immense space of time. Their petrified remains, especially those of THE RED ALG. 9! the Silurian period, which have been preserved, can, it is true, give us but a faint idea of them, because the material of these Algze, like that of most others, is ill-suited for pre- servation 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 Algz, that of the Rose-coloured Alge (Rhodophycee), or Red Sea-weeds (Flo- ridez). This class, it is true, presents a great number of different forms; but most of them are of much smaller size than the Brown Alez. Although they are inferior to the latter in perfection and differentiation, they far surpass them in some other respects. To them belong the most beau- tiful and elegant of all Algze, 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 some- times 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 Floridez, which are fre- quently dried on white paper and offered for sale. Most of the Red Alge 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 in- dividual forms, like the Chondria and Spheerococca, 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 92 THE HISTORY OF CREATION, an important share in the composition of the archilithie Algee flora. If we now again take into consideration the flora of the primordial period, which was exclusively formed by the group of Aloz, 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 primzeval 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 Alge, or Fucoideee. The many-coloured flowers at the foot of these gigantic trees were represented by the gay Red Algze, or Floridez. The green grass between was formed by the hair-like bunches of Green Algze, or Chloroalgze. 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 Siphoneze, in the Caulerpa and Bryopsis, from among the class of the primary Algze, Protophyta, or Archephycez. With regard to the relationships of the different classes of Algze to one another and to other plants, it is exceedingly probable that the Primary Algz, or Archephycez, as already remarked, form the common root of the pedigree, not merely for the different classes of Algz, but for the whole vege- table kingdom. On this account they may with justice be designated as primzeval plants, or Protophyta. Out of the naked vegetable Monera, in the beginning of the THE THREAD PLANTS. 93 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 Aleve, Brown Alge, and Red Algze, are perhaps three distinct classes, which have arisen in- dependently of one another out of the common radical group of Primzeval Algze, and then developed themselves further (each according to its kind), and have variously branched off into orders and families. The Brown and Red Alge possess no close blood relationship to the other classes of the vegetable kingdom. These latter have most probably arisen out of the Primeval Algee, either directly or by the inter- mediate step of the Green Algz. It is probable that Mosses (out of which, at a later time, Ferns developed) proceeded from a group of Green Algez, and that Fungi and Lichens proceeded from a group of Primezeval Aloz. 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 under- stood by this term the two closely related classes of Lichens and Fungi. Itis possible that these Thallus plants have not arisen out of the Primeval Algz, 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 94 THE HISTORY OF CREATION. 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 hyphee, 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 palzeontological development. The first class of Thread-plants, the Fungi, exhibit a very close relationship to the lowest Alge; the Algo-fungi, or Phycomycetes (the Saprolegnise and Peronosporee) in reality only differ from the bladder-wracks and Siphones (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 ORIGIN OF FUNGL 95 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 Pro- tista 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, neve1 form any hyphz). 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 Siphonez (especially between the Saprolegniz and Vaucheriz) suggests to us that they are derived from the latter. Fungi would then have to be con- sidered as Algze, 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 alow form of Alga (Nostochaceze, Chroococcaceze), and of a parasitic form of Fungus (Ascomycetes), which lives as a parasite upon 96 THE HISTORY OF CREATION, 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 (hyphz) which, densely interwoven, form the princi- pal 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 irregu- larly indented, erust-like coverings to stones, bark of trees, ete. 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 PROTHALLUS PLANTS. 97 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 Algz, 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 contradis- tinction 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 Linnzus 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 Prothalliwm, 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 Pro- 98 THE HISTORY OF CREATION. thallus, 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, ete, the second like the fourth, sixth, ete. (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 Algze 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 Algze. Ferns, on the other hand, are probably derived from THE MOSSES. 99 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 (Muscine, 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 recog- nizable 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 Algz. 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 develop- ment of which comparative anatomy may draw some infer- ences 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 Aleve, or Confervee, is formed by the Lwer- worts (Hepatic, or Thallobrya). The mosses belonging to them are, for the most part, small and insignificant in form, and are little known. Their lowcst forms still possess, in both generations, a simple thallus like the Thallus plants ; as for example, the Riccize and Marchantiaceze. But the more highly developed liverworts, the Jungermanniaceze 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 [OO THE HISTORY OF CREATION. the liverworts show their direct derivation from the Thallophytes, and more especially from the Green Algee. 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 dis- appear the useful reservoirs which stored up ram 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. Un- fortunately 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 COAL PLANTS. IOI tender bodies are as little suited as those of all other mosses for being preserved in a fossil state, paleontology 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” (Filicineze, or Pteridez, also called Pteridophyta, or Vascular Cryptogams), formed during an extremely long period, namely, during the whole primary or palzeolithic 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 pre- served remains of Ferns, that we can form a tolerable vivid picture of the very peculiar land flora of the paleolithic period. In the year 1855 the total number of the then known paleeolithic 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 Algze), and about 20 not accurately definable Cormophyta (stem-plants). As already remarked, Ferns probably developed out of the tower liverworts in the beginning of the primary period. [O2 THE HISTORY OF CREATION. 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 cel’; 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 eryptogams” (Mosses and Thallus plants). This very important process in the organization of plants—the formation of vessels —first occurred, therefore, in the Devonian period, con- sequently in the beginning of the second and smaller half of the organic history of the earth. The branch of Ferns, or Filicinz, is divided into five distinct classes: (1) Frondose Ferns, or Pteride; (2) Reed Ferns, or Calamaria; (3) Aquatic Ferns, or Rhizocarpez ; (4) Snakes Tongues, or Ophioglosse; 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 princi- pal portion of the palzeolithic 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 palzolithic fern forests, in which the whole of the gay abundance of flowers of our present flora was entirely wanting, and which were not enlivened BOTANISTS AND DARWINISM. 103 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 Coniferze and Gnetacez,” 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 Pteridze). 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 I04 THE HISTORY OF CREATION, ~ 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 palzeolithic 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 Calamarize, Ophioglossee, and Rhizocarpeze seem to have developed as three diverging branches out of the Frondose Ferns, or Pteridee. The Calamari, or Calamophyta, have remained at the lowest level among these three classes. The Calamariz comprise three different orders, of which only one now exists, namely, the Horse-tails (Equisetacez). The two other orders, the Giant Reeds (Calamiteze), and the Star-leaf Reeds (Asterophylliteze), are long since extinct. All Calamarize 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 LITTLE-KNOWN FERNS. 105 separated from one another by partition walls. In Horse- tails and Calamitez 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 Asterophyllitez, the star-shaped whorls of leaves were more strongly developed than in the two other orders. There exist, at present, of the Calamariz only the in- significant 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, con- tained 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 (Rhizorcarpeze, or Hydropteridee), 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 106 THE HISTORY OF CREATION. was already developed during the paleeolithic period out of other ferns by adaptation to an aquatic life. The fourth class of ferns is formed by the Tongue Ferns (Ophioglossze, or Glossopterides). These ferns, to which belongs the Botrychium, as well as the Ophioglossum (adder’s-tongue) of our native genera, were formerly con- sidered as forming but a small subdivision of the frondose ferns. But they deserve to form a special class, because they répresent important transitional forms from the Pterideee 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 Ophioglossze arose out of the frondose forms, the scale ferns arose out of the Ophioglosse, 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 paleolithic 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 (Lycopodiacez). 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 CLUB-MOSSES, 107 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 clwb-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 (Liycopodites). The most important dimensions were, how- ever, attained by the class of scale trees (Lepidodendresee), and by the seal trees (Sigillarieze). 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 Lepidodendrez, were probably more closely related to club-mosses than to Sigillariez, 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, Sigillarieze, which in many places form the princi- pal part of coalseams. Their roots were formerly described as quite a distinct vegetable form (under the name of Stigmaria). The Sigillarieze are in many respects very like 108 THE HISTORY OF CREATION. the scale-trees, but differ from them and from ferns in general in many ways. They were possibly closely related to the extinct Devonian Lycopteridewe, combining character- istic 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 (Lepidodendreze and Sigillarieze), we pass onwards to the no less character- istic 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 Phanero- gamia, 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 palzeolithic 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 relation- ship. 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 Lycopodiacez, forms THE FLOWERING PLANTS. 109 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 embryo- logical 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 Archispermee, or Gymnosperms (with naked seeds), attained its most varied development and widest distribution during the mesolithie 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 Gymno- ° sperms, or after its most important representatives, the era of Pine Forests. The Gymnosperms are divided into three classes: the Coniferze, Cycadez, and Gnetacez. 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 | ie) THE HISTORY OF CREATION. of the Palm Ferns (Zamiz, or Cycadeze) 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 (Cycadeze) is pre- sented by the extinct and fossil Cycads, which occurred in sreat 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 (Coniferze), has pre- served 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, ete.—still play a very important part in the most different parts of the earth, and almost of themselves consti- tute 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 ANGIOSPERMS, III 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 indivi- duals—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 Cycadez predominate over those of coniferous trees in the Jura period.* From the pine forests of the mesolithic, or secondary period, we pass on into the leafy forests of the czenolithic, or tertiary period, and we arrive thus at the consideration of the sixth and last class of the vegctable kingdom, that of the Metasperme, Angiosperme, 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 &wo classes into which the main class of Angiosperms is generally divided, namely, the one seed-lobed plants, or monocotyle, and the two seed-lobed plants, or dicotyla. 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 Monocotyle, whilst others consider them as Gymnosperms. In regard to the two classes of * The primary stock of the Coniferze divided into two branches at an early period, into the Araucariz on the one hand, and the Taxaceex, or yew-trees. on the other. The majority of recent Coniferz are derived from the former. Out of the latter the third class of the Gymnosperms—the Meningos, or Gnetaceze—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 Coniferze to the Angiosperms, and more especially to the Dicotyledons. I12 THE HISTORY OF CREATION. plants with enclosed seeds, the Monocotyle and Dicotyle, it is exceedingly probable that the Dicotyledons developed out of the Gnetacez, but that the Monocotyledons developed later out of a branch of the dicotyledons. The class of one sced-lobed plants (Monocotyle, or Monocotyledons, also called Endogenze) 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, ete, and finally the splendid and highly developed families of the Aroideze and Pandanez, 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. The second class of plants with enclosed seeds, the two seed-lobed (Dicotyle, or Dicotyledons, also called Exogenze) presents much greater historical and anatomical interest in of the : Ay ay k egetable Thallusplants, Thallophyta. "yaa a, sie Cover-seeded, Angiospermae. . S Tangles, Algae. a 4 ite: One Germ Two Germ Leaves, Dicotylae. en Gn | Henge | rd, bite, Mouldeliohens| Hepa | Fon. ose 3 S : Prutop laf har dea ie | Fey tone. | Chasvos Funge. A . = . Monocotylae. l ia i : ; y ‘ | AON ATEN \ VAAN , ) vid PW S27) PASM Uy ee y MA I Ng S\N) aN \ N i \ ys Y Mi "i v “ee h4 v 4 4 ( BN SUN, VN RW) AA AN i LO tes Ses <= < <—S es \ | iy j . S mA ees S asssad nasal | Relative lengths of the 5 ; Epochs in per-centages. Single-stemmed or Quarternary Epoch 0.5 MONOPHYLETIC PEDIGREE Tertiary Epoch... 2.3 of the Secondary Epoch 11.5 | WEGETABLE KINGDOM Primary Epoch.......32.1 : Primordial Epoch 53.6 based.on Paleontology. Total 100.0 fo ey) jai a Sy - ree Hee ai, + BT eA) ieee THE FLOWERING PLANTS, EES 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 Mono- cotyledons; 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 cznolithie 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 Gnetacez. In the lower Dicotyledons, as in the case of the Monocotyledons, calyx and corolla are as yet not differentiated. Hence they are called Apetalous (Monochlamydez, or Apetalee). This sub-class must there- fore 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 growp with corollas (Dichlamydez, or Corolliflorze). These arose out of the Apetalze from the simple cover of the 23 II4 THE HISTORY OF CREATION, blossoms of the latter becoming differentiated into calyx and corolla. The sub-class of the Corolliflorz 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 Diapetalz, the second that of the bell-flowers, or Gamopetalee. The lower and less perfect of the two legions of the Corollifloree are the star-flowers (also called Diapetalze or Dialypetalee). To them belong the extensive families of the Umbelliferze, or umbrella-worts (wild carrot, ete.), the Cruci- ferze, or cruciform blossoms (cabbage, etc.); further, the Ranunculacese (buttercups) and Crassulacez, 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 Diapetalz. the ‘blossom-leaves remain separate, and never grow together, as is the case in the Gamopetalie. These latter developed first in the tertiary period out of the Diapetalze, whereas the Diapetalze appeared in the chalk period together with the Apetalee. : The highest and most perfect group of the vegetable kingdom is formed by the second division of the Corollifloree, namely, the legion of bell-flowers (Gamopetalz, also called Monopetalee or Sympetale). 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 THE DESCENT THEORY CONFIRMED, II5 other families, the extensive division of the Lip-blossoms (Labiatze) and the Composites. In these last the differen- tiation 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 Gamopetalze appear in the organic history of the earth later than all the main groups of the vegetable kingdom—in fact, not until the ceenolithic 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 qua- ternary 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 them- selves 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 perfec- tion, 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 Algz. 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 116 THE HISTORY OF CREATION, 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 Apetale. It was not until the chalk period that the higher Corollifloree 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 Diapetale, and only at quite a late date, in the tertiary period, did the more highly developed Bell- _ blossoms, Gamopetalz, 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.—Linnzus and Lamarck’s Systems.—The Four Types of Bar 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 Primzval 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.—Pri-. meval Animals (Monera, Amcebe, Synamcebee), Gregarines, Infusoria, Planzades, and Gastrzeades (Planula and Gastrula).—Tribe of Zoophytes. —Spongize (Mucous Sponges, Fibrous Sponges, Calcareous Sponges).— Sea Nettles, or Acalephz 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 118 THE HISTORY OF CREATION. Linneus. 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, charac- teristics, which readily strike the eye. Thus Linnzus dis- tinguished 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 Linnzeus 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 Linnzeus), 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 Bar and George Cuvier. As has already been remarked, they established, almost simultaneously and independently of one another, the pro- position that it was necessary to distinguish several com- pletely distinct main groups in the animal kingdom, each of TYPES IN THE ANIMAL KINGDOM. II9 which possessed an entirely peculiar type or structure (com- pare 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 Bar, 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 re- markable 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 in- heritance, and the degree of development or differentiation by adaptation. (Gen. Morph. ii. 10). Both Bar 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 Linnzeus’ first four classes—mammals, birds, amphibious animals, and fishes. The second type is formed by the articulated animals (Articulata), containing Linnzeus’ insects, consequently the six-legged insects, and also the 120 THE HISTORY OF CREATION. myriopods, spiders, and crustacea, but besides these, a large number of the worms, especially the rmged 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 Bar and Cuvier was the greatest advance in the classification of animals since the time of Linneus. The three groups of vertebrated animals, articu- lated 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 poimted 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 (Ccelenterata, THE SEVEN MODERN TYPES. 121 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 Linneus’ 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 Linnzeus, 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 122 THE HISTORY OF CREATION, anatomy and ontogeny. Besides these, paleontology 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 Bar 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 ¢ Haeckel History of Creaizon. PL.VI. 7\'—Cenolithic (fet eae | Animals nee a 3 II, Mulberry animal z0a ; y mals : Protozo Blastularia { 5. B. III. Sponges { 6 Animal Spongice : IBlants IV. Sea-nettles 8 Zoophyta Acalephe y V. Bloodlessworms $ 10. C. Acalomi 1 Otiorms VI. Blood-bearing [ 12 worms 13 Vermes Cealomati 14 15 16 “17 D VII. Headless shell- iH fish 19. A olluses Acephala VIII. Head-bearing ¢ 20, Mollusca Eucephala r 1 21. BR. IX. Ringed-arms % tar-fish os Colobrachia i 23. - X. Armless 24. Hehinoderms, teen | FB. XI. Gill-breathers { 26 Articulated Carides Animals —) x1, Tube-breathers | 54° Arthropoda Tracheata 29, XIII, Skull-less Acrania { 30. G. DV. Sng nos- { . rile if Dertebrate Monorrhina Animals hy ailiok 4 M 32 , Amnion-less : Vertebrata Anamnia | 34. 30 * XVI. Amnion-_ {36 bearing 37 Amniota 38 Archaic animals . Gregarines . Infusoria Planzads Gastreads . Sponges . Corals . Hood-jellies . Comb-jellies Planary worms . Round worms . Moss-polyps . Sac- worms . Proboscideans . Star-worms . Wheel animal- cules . Ring-worms 18. Lamp-shells Mussels Snails Cuttles 22. Sea-stars Lily -stars Sea-urchins Sea-cucumbers Crab-fish Spiders Centipedes Flies Lancelets Lampreys . Fishes . Mud-fish Sea-dragons . Amphibians . Reptiles . Birds . Mammals. Systematic Name of the Classes. . Archezoa . Gregarine Infusoria Planzadas Gastreadas Porifera . Coralla . Hydromeduse . Ctenophora . Platyhelminthes . Nemathelminthes . Bryozoa . Tunicata . Rhynchocela . Gephyrea . Rotatoria Annelida . Spirobranchia Lamellibranchia . Cochlides Cephalopoda . Asterida . Crinoida . Echinida . Holothuriz . Crustacea . Arachnida . Myriopoda . Insecta . Leptocardia . Cyclostoma . Pisces . Dipneusta . Halisauria . Amphibia . Reptilia Aves 38. Mammalia MONOPHYLETIC PEDIGREE OF ANIMALS, 133 Vertebrata (Vertebrated animals) Craniota Arthropoda Mollusca : (Articulated Animals) (Molluscs) Echinoderma Tracheata Eucephala (Star-jishes) | Lipobrachia Crustacea Acrania Annelida | Tunicata Acephala Colobrachia eons Gephyrea Rotatoria bere set | Vermes (Worms) C@.Lomat! (Worms with a body-cavity) Platyhelminthes Zoophyta THis ica (Animal Plants) Acelomi Spongize Acalephs (Worms without body-cavity) Protascus Prothelmis Pere parks cia! | Protozoa. (Primeval animals) ee ne a ae ae GastTR#A Infasoria PLANEA Gregarinse SYNAM@BE ee WM _-_- —-—--——" AM@BE MONERA 134 THE HISTORY OF CREATION, 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, Gregarine, and Infusoria, to the latter the two classes of Planzeads and Gastrzeads. 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 per- fectly 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 Amcebze ; (3) Animal Synamcebze. We may, if we choose, include among them a portion of the still living Monera and Amcebx, but another portion (ac- cording 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 con- sidered as plants. A second class of the egg animals consists of the Grega- rines (Gregarinz), which live as parasites in the intestines and, body-cavities of many animals. Some of these Grega- rines are perfectly simple cells like the Amcebze ; some form chains of two or three identical cells, one lying behind the other. They differ from the naked Amcebz by possessing CLASSES OF EGG-ANIMALS, 135 _ a thick, simple membrane, which surrounds their cell-body ; they can be considered as animal Amcebe 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 (Acinetze), 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 in- visible 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 Amcebe. The second main class of primeval animals consists of the Germ anvmals (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 136 THE HISTORY OF CREATION, (vegetative or gastral) mass. Whether there still exist _ representatives of this group is uncertam. 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 Planeada and Gastreada. The type of the Planeada is the Planwa—long since extinct—but whose historical por- trait is still presented to us at the present day in the widely distributed ciliated larva (Planula). (Frontispiece, Fig. 4.) The type of the Gastrwada is the Gastrewa, 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 Gastrea, as we have previously mentioned, there were at one time developed two different primary forms, the Pro- tascus 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 Caleareous Sponges, vol.i. p. 464.) The Animal-plants (Zoophyta, or Coelenterata) which con- stitute the second tribe of the animal kingdom, rise con- siderably 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 excep- tion only of the lowest forms) the four distinct functions of nutrition—namely, digestion, circulation of the blood, respiration, and excretion—are universally accomplished by THE ANIMAL-PLANTS, 137 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 ccelenteric 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 “cceloma,” possessed by the four higher tribes of animals is still completely wanting, likewise the vascular system and blood, as also the organs of respiration, ete. 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 primeval polyps (Hydra, Cordylo- phora). 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 Spongie, and the Sea- nettles, or Acalephe (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-netiles. 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 24 138 THE HISTORY OF CREATION, 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, con- sists of two layers or coats of cells, a fringed entoderm, or gastral layer (corresponding with the inner or vegeta- tive 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 eal the most ancient group of vegetable animals, represented by the Protascus-type— divided into two lines or branches, the Spongiz and the Sea-nettles, or Acalephz. 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 Spongize, which I THE SPONGES. | 139 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, Spongie, or Porvfera, 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 primeeval animals, or Protozoa. But since I have demonstrated their develop- ment 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 unmistak- able light upon this point. The numerous forms comprised in the class of Spongise 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 (Myxospongie), 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 obtaina notion of the Archispongia, the most ancient primeval sponge, if we imagine the Olynthus (see Frontispiece), to be deprived of its radiating calcareous spiculz. 140 THE HISTORY OF CREATION, The second legion of Spongiz contains the Fibrous Sponges (Fibrospongiz), 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 Inherit- ance, be so clearly followed step by step; perhaps in no other group is the species so difficult to limit and define. 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 (Calcispongize), on which in 1872, after five years’ careful examination, I published a comprehensive Mono- graph. The sixty plates of figures accompanying this Mono- graph explain the extreme pliability of these small sponges PL Vil. is lacekel de B rt E bal J Saari ( a ) ¥ .) pier ) 4) ‘ ti Cais pe a AY Pee Par [yy ia) iA 4 4 yar Webi Dh Alet hp a RAM mea Paley te re eV OAN ‘ 5 Us ‘ ar i + ey ‘ Fi \ : it Be : ; ai i CA saat i ‘ i cy WT | | se ‘ ‘ a) : « j ‘ , ' a ‘ ‘ wal : 4 - : ‘ iy a ‘ * | ’ . ‘ ‘ . / ’ - ' os : 4 4 t | f ui * Dp? 7 4 ‘ ‘ : * ‘ ‘ a ‘ t @ a yet ‘ ‘ ole ' ¥ ”* 9 U / eieur ‘ up i ‘ be veh 4 rttPel u ¢ ‘ Var . , LP | tie a ' L/ * . is * x ey ee ; a. ( : ‘ - ue - ‘ . « Q : ww i ’ ‘ ’ ’ f, : ‘i 4 he aks LS 4 / ' a " 1¥ j f 14 4 . i j ou a ? oe . THE CALCAREOUS SPONGES, Iq! “ 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 accord- ing 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 Frontis- piece), the order of the Ascones was the first to develop, out of which, at a later period, the two other orders of Cal- careous Sponges, the Leucones and Sycones, arose as diverg- ing 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 pro- position which [ 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 (Acalephe, or Cnide). This interesting group of animals, so rich in forms, is composed I42 THE HISTORY OF CREATION, of three different classes, namely, the Hood-jellies (Hydro- medusz), 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 Spongiz (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 Hydromeduse. The Ctenophora de- veloped later out of a branch of the latter. The Sea-nettles differ from the Spongiz (with which they agree in the characteristic formation of the system of the alimentary canal) principally by the constant posses- sion 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 con- tact with large Hood-jellies (Jelly-fish), and become ac- quainted 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, THE FLOWER-ANIMALS, 143 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 im- mense 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 re- markable forms of which were first explained by Darwin.” In corals the counterparts, or antimera—that is, the cor- responding divisions of the body which radiate from and surround the central main axis of the body—exist some- times 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 Hight- fold corals (Octocoralla), The fourfold corals form the common primary group of the class, out of which the six- fold and eightfold have developed as two diverging branches. The second class of Sea-nettles is formed by the Hood- — jellies (Medusze) or Polyp-jellies (Hydromedusz). 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 Primeval polyps (Archydre), from which, during the primordial period, the whole division of the Sea-nettles 144 Classes of the Zoophytes. z. Sponges Spongie or Porifera II. Corals Coralla or Authozoa ate. Iellv-polvps Hydromeduse or WH oov-jellies Medusa IV. Comb-jellies Ctenophora THE HISTORY OF CREATION, SYSTEMATIC SURVEY Of the 4 Classes and 30 Orders of the Animal Plants, or Zoophytes. Legions of the | Orders of the Zoophytes. Zoophytes, I. Myxospongize ; a Mucous Sponges 2. Halisarcina II. Fibrospongie { 3° Ghalynthina Fibrous Sponges 5. Hexactinella III. Calcispongize % prec, 2 Calcareous Sponges 8. Sycones IV. Tetracoralla ; 9. Rugosa Fourfold Corals 10, Paranemeta V. Hexacoralla ( me sap eae Siafold Corals | 43" Hratirhoda VI. Octocoralla a ai ad Eightfold Corals 16, Pe fis iida VII. Archydree \ ‘3 Primeval Polyps 17. Hy ee VIIL. Leptomeduse ei tite ae 20. Siphonophora 21. Marsiporchida ce ae 22. Phyllorchida adele G8) 23. Elasmorchida X. Calycozoa +s Stalked Jellies sincoasy ao XI. Discomedusza ee Semseostomeze Disc-jellies 26. Rhizostomeze XII. Eurystoma ; Wide-nouthed A; 21 Pere 28. Saccata XIII. Stenostoma 29. Lobata Narrow-mouthed 30, Toeniata A Genus Name as example. . Archispongina| Archispongia Halisarca Spongilla Ancorina Euplectella Olynthus Dyssycus Sycurus Cyathophyllum Cereanthus Antipathes Astrea Actinia Lobularia Isis Veretillum Hydra Sertularia Tubularia Physophora Trachynema Geryonia Charybdz Lucernaria Aurelia Crambessa Beroe Cydippe Eucharias Cestum Ss PEDIGREE OF ZOOPHYTES, 145 Ctenophora Hydromedusss Tceniata Lobata Bhizostomez UY Semzeostomesa Saccata DISCcOMEDUSZ STENOSTOMA Trachymedusx Siphonophora Lucernaria EurystoMa Calycozoa ee LEPTOMEDUSE Coralla Octocoralla Hexacoralla Tetracoralla Spongia Fibrospongize Calcispongize Chalynthina Leucones Sycones Hexactinella|Geodina Dyssycus Sycurus Hydroida | | Cordylophora Hydra ) Ascones | Myxospongia Se Halisarcina HyYDROIDA Procorallum CHALYNTHUS OLYNTHUS | ee FY Hydroida Archispongiz Archydra (nin pe aie Protascus Gastrea 146 THE HISTORY OF CREATION. originated. Scarcely distinguishable from the Hydra are the adherent Hydroid polyps (Campanularia, Tubularia), which produce freely swimming medusze 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 me- dusze, are among the strongest proofs of the truth of the theory of descent. For just as Medusz 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.™ (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 cu- eumber, 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 WORMS. 147 The third tribe of the animal kingdom, the phylum of Worms or worm-like animals (Vermes, or Helminthes), con- tains 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 ar- rangement 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 at- tempt to throw a few hypothetical rays of light upon the obscurity of the pedigree of Worms, I must therefore 148 THE HISTORY OF CREATION. 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 accord- ing 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 Accelomi 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 ecelome) ; they are, there- fore, called Accelomi. The true cavity, or ccelome, is com- pletely absent in them as in all the Zoophytes ; in this im- portant 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 Colomatt. The main division of Bloodless Worms (Accelomi) con- tains, 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 Primeval Worms (Archelminthes). The type of these Primeval Worms, the ancient Prothelmis, may be directly derived from the Gastrea (p. 133). Even at present the Gastrula-form — the faithful historical portrait of the Gastrzea—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 THE WORMS. 149 nearest akin to the Primzval 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 Accelomi arose the second main division of the Worm tribe, the Worms with blood and body-cavity (Ccelomati): of these there are seven different classes. The Pedigree on p. 151 shows how the obscure phylogeny of the seven classes of Ccelomati 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 Ceelomati will at some future time throw light upon their phylogenesis. The Round Worms (Nemathelminthes) which we mention as the first class of the Ccelomati, and which are character- ized by their cylindrical form, consist principally of para- sitical Worms which live in the interior of other animals. Of human parasites, the celebrated Trichine, 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 seg- ments, all alike in structure, belong the Leeches (Hirudinea), Earth-worms (Lumbricina), and all the marine bristle-footed Worms (Chzetopoda). Nearly akin to them are the Snout- worms (Rhynchoccela), and the small microscopic Wheel- 150 THE HISTORY OF CREATION. SYSTEMATIC SURVEY Of the 8 Classes and 22 Orders of the Worm Tribe. (Compare Gen. Morph. II. Plate V. pp. 75-77.) Classes Orders of the a Name of a Gen Worm Tribe ee Orders af Worms. ao ceample. 1. Flat 1. Primzeval worms 1. Archelminthes Prothelmis ; Worms 2. Gliding-worms 2. Turbellaria Planaria Swen 3. Sucker-worms 3. Trematoda Distoma pee ee Tape-worms 4. Cestoda Tenia 2. Round 5. Arrow-worms 5. Cheetognatha Sagitta Worms } 6. Thread-worms 6. Nematoda Trichina aresec an 7. Hook-headed 7. Acanthocephala | Echinorhynchus worms 3. Moss 8. Horse-shoe-lipped 8. Lophopoda Alcyonella ae con J 9. Circle-lipped 9. Stelmopoda Retepora eee 0. Sea-squirts 10. Ascidia Phallusia Tunicata | 11. Sea-barrels 11. Thaliacea Salpa 5. Probos- cideans | 12. Tongue-worms 12. Enteropneusta Balanoglossus Rhyncho- { 13. Cord-worms 13. Nemertina Borlasia cela 6. Star. 14. Star-worms with- | 14. Sipunculida Sipunculus ee out bristles Gephyrea | 15. Star-worms with | 15. Echiurida Echiurus bristles 7. Wheel Animatele| 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 a lst 20. Land-worms 20. Drilomorpha Lumbricus mnenc® | 21. Mailed worms 21. Phracthelminthes| Crossopodia 22. Bristle-footed 22. Chactopoda Aphrodite worms PEDIGREE OF WORMS, I5!I Chzetopoda rine a Phracthelminthes Echiurida Hirudinea Sipunculida Onychophora a Arctisca Gephyrea ———" Cheetognatha ————— | —— Nematoda | Annelida Acantho- cephala |Stelmopoda Enteropnenusta ——__—[Lophopoda Ascidia Nemathelminthes| Bryozoa Thalicea Nemertina Rotifera —_— Rhynchocela | | Tunicata oS ee Coelomati (worms with body-cavity) Cestoda Trematoda Turbellaria Platyhelminthes Acclomi (worms without body-cavity) Archelminthes Prothelmis Gastrea 152 THE HISTORY OF CREATION. 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 Ccelomati, whose nearest kin of the present day are the Sea-sacs, especially the Ascidia. The class of Sea-sacs (Tunicata) is one of the most remarkable among Worms. They all live in the ocean, where some of the Ascidiz 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 cartila- ginous 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 King- dom, 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 ap- pendages. No one would recognise in them a trace of rela- tionship 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 indi- vidual deveiopment of the adherent simple Ascidian Phallusia agrees in most points with that of the lowest vertebrate animal, namely, the lLancelet (Amphioxus lanceolatus). ASCIDIANS AND VERTEBRATES. 153 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 Ccelomatous group of the Worms furnish us with several genealogical links leading to the four higher tribes of animals, and give us im- portant phylogenetic indications of their origin, the lower group of Accelomi, on the other hand, show close relation- ships to the Zoophytes, and to the Primzeval animals. The great phylogenetic interest of the Worm tribe rests upon this peculiar intermediate position. 154 THE HISTORY OF CREATION CHAPTER XIX. PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM. II. Mottusca, Srar-FISHES, AND ARTICULATED ANIMALS. Tribe of Molluscs.—Four Classes of Molluscs: Lamp-shells (Spirobranchia) ; Mussels (Lamellibranchia) ; Snails (Cochlides) ; Cuttle-fish (Cepha- lopoda).—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.—Chew- ing and Sucking Insects.—Pedigree and History of the Hight Orders of Insects. THE great natural main groups of the animal king- dom, which we have distinguished as TRIBES, or PHYLA (“types ” according to Bir 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 asingle series of stages, one above another, nor be con- sidered as entirely independent stems, nor as equal branches of asingle family-tree. It seems rather (as we saw in the last chapter) that the tribe of Protozoa, the so-called primeval animals, is the common radical group of the whole animal kingdom. Out of the Gastreeada—which we class among THE MOLLUSCS. 155 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 ex- amination 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 morpho- logical 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 per- fection. The body in all Molluscs—in mussels, snails, ete— 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 156 THE HISTORY OF CREATION. perfect forms) to be morphologically the lowest among the four higher tribes of animals. Whilst, for reasons already given, we exclude the Moss- which have hitherto been generally polyps, and Tunicates classed with the tribe of Molluses—we retain as genuine Molluses the following four classes: Lamp-shells, Mussels, Snails, and Cuttles. The two lower classes of Molluses, 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 (Odonto- phora), because both head and teeth are developed in them. The soft, sack-shaped body in most Molluses 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 neptunie 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, con- jointly with much other evidence, distinctly prove, that the tribe of Molluscs had then obtained a strong development, when the higher tribes, especially the THE PEDIGREE OF MOLLUSCS, 157 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. (Com- pare 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 th2 greatest importance because they serve as excellent marks whereby to charac-, terize 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 de- pendent upon the records of ontogeny and comparative anatomy from which we obtain: something like the follow- ing 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 158 THE HISTORY OF CREATION. 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 Molluse 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. 2. Mussels i Acephala. (Lamellibranchia). II. Otocardia 3. Snails (with chamber parents (Cochlides). and ante-chamber ashe si x 4. Cuttles to the heart). ritlaee iteer (Cephalopoda). THE PEDIGREE OF MOLLUSCS. 159 The result of these structural dispositions for the history of the pedigree of Molluscs, which is confirmed by pale- ontology, is that Lamp-shells stand much nearer to the primeeval 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 character- ized 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) t.) 26,800. 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), 160 THE HISTORY OF CREATION, 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. iz I. Ecardines i 1. Stalked 1. Lingulida Lamyp-shells Hinge-less 2. Flattened 2. Craniada Spirobranchia or Brachiopoda II. Testicardines { 3. Fleshy armed 3. Sarcobrachia Hinge-less 4. Calcareous-armed 4, Sclerobrachia nt III. Asiphonia 5. One-muscled 5. Monomya Z I Mussels without re- { 6. Uneven-muscled 6. Heteromya {ussels spiratory tubes 7. Even-muscled 7. Isomya or Blate-gills nn IV. Siphonida 8, Round-mantled 8. Integripalliata 2 Mussels with respi- 9. Bay-mantled 9. Sinupalliata Phyllobranchia ratory tubes {2 Tube-mussels 10. Inclusa II. Molluscs with head and teeth: CEPHALOPHORA or ODONTOPHORA. V. Stump-headed 11. Tube-snails 11. Scaphopoda Perocephala {1 Butterfly-snails 12. Pteropoda III. 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 withlungs 17. Pulmonata VII. Chamber-Poulps (18. Pearl boats 18. Nautilida IV. with four gills iC Ammon’s horns 19. Ammonitida Cuttles Tetrabranchia or Boulps ; : VIII. Ink-Poulps with (20. Ten-armed 20. Decabrachiones Cephalopoda two gills Dibranchia 21. Eight-armed 21. Octobrachiones PEDIGREE OF MOLLUSCS, 161 Dibranchia Heteropoda Prosobranchia Pulsnonata Tetrabranchia Lipobranchia Cephalopoda (Cuttles or Poulps) Gymnobranchia Pleurobranchia —,——’ Opisthobranchia Chitonides | ee es ee ees’ Delocephala a Pteropoda Inclusa | ——_" Sinupalliata Scaphopoda | Integripalliata W—_——— Sclerobrachia Siphoniata Perocephala Cochlides (Snails) Sarcobrachia Asiphonia Testicardines Lamellibranchia (HAlussels) Ecardines een: Spirobranchia Otocardia (Lamp-eshells) (Molluscs with chamber and ante- chamber to the heart) Ne NT Promollusca (Primeval Molluscs Molluscs with simple heart (Worms) Gastreea 25 162 THE HISTORY OF CREATION. 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 Molluses 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 Newis 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 ina 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 evi- dences 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 diffesent sub-classes and orders, distinguished in the four classes of Molluscs, whose systematic succession is THE STAR-FISHES. 163 given on the Table (p. 160), furnish various proofs of the validity of the law of progress by their historical develop- ment 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 consider- ation of the tribe of Star-fishes, The Star-fishes (Echinoderma, or Estrelle) 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 remark- able apparatus for locomotion, which consists of a eompli- cated 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. 164 THE HISTORY OF CREATION, 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 ecal- eareous 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 develop- mental history, and by their interesting comparative ana- tomy ; 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 com- parison 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 COMPOUND NATURE OF STAR-FISHES. 165 -Echinoderma is limited, without exception, to five. Every Star-fish consists of a central, small, body-dise, all round the circumference of which are attached five or several long articulated arms. Hach arm of the Star-fish essentially corresponds in its organization 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 diges- tive cavity (stomach) lying in the central body-dise. 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 Botryllide, compound Ascidians, belonging to the class of the Tunicata. Here also the pos- terior 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 pos- sesses 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. 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 166 SYSTEMATIC THE HISTORY OF CREATION. 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 Star-jishes. Starjishes. Star-jishes. / 1. Primary Stars Sea AKG with ra- 2. Articulated Stars diated stomach 3. Brisinga Stars Sea Ke. rae te Asterida 4. Serpent Stars Sea Bion San disc-{ 5, Tree Stars , Shaped stomach 6. Lily Stars Discogastra III. 7. Plated Lilies with Lilies with arms —e ae eS 8. Articulated Lilies with arms 9, Regularly budding ey ae Lilies ah buds lilies Crncide Blastoidea 10. Lilies budding on two sides fe 1. Bladder Lilies without stalks Blader rg 2. Bladder _Lilies y with stalks 3. Palechinida with more than 10 Older a Teabags rows of ambu.- (with more than lacral plates 20 rows of plates) |14. Palechinida with Palechinida 10 rows of am. ara ae bulacral plates Echinida VII. . Autechinida with More recent Sea Urchins (with 20 rows of plates) Autechinida Vill. Sea Cucumbers with aquatic feet a. Sea hiasate Holothurice Sea eee without aquatic feet Apodia . ; Se : band-like am- bulacra 15 16. Autechinida with leaf-like ambulacra 17. Eupodia with scu- fe i i tiform tentacles Eupodia with branching ten- tacles lungs s 20. Apodia without water-lungs Systematic Name of 14. 15. 16. 17. 18, the Orders. . Tecastra Colastra Brising- astra Ophiastra Phytastra Crinastra Phatnocri- nida . Colocrinida . Pentremi- tida . Eleuthero- crina . Agelacri-. nida . Spheroni- tida . Melonitida Eocidaria Desmo- sticha Petalo. sticha Aspidochi. rota Dendrochi. rota 19. Apodia with water- 19. Lioderma. tida 20. Synaptida PEDIGREE OF STAR-FISHES. 167 Clypeastridze Spatangidee Dysasteridze Aspidochirota Sie Synaptida Cassidulidee Petalosticha Liodermatida | Apodia = Sa .. ~BMechinosike Galeritidee Echinometridze SSS eee Dendrochirota Eupodia Latistelles Holothurize Salenidse | Angustistelles Desmosticha Autechinida Colocrinze F | Spheeronitidee Phytastra Eocidaridee Eleutherocrina Ophiastra Agelacrinzs Discogastra Cystidea Melonitida Phatnocrins Brisingastra Palechinida Brahiata Pentremitida Echinida Blastoidea Colastra ee eee cae ao Brachiata Crinoida Crinastra Ms eg Po ee Tocastra Actinogastra Asterida | Phractelminthes Coelomati Gastraa 168 THE HISTORY OF CREATION, anatomy, and by the ontogeny of some Star-fishes (Co- lastra), 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 mem- bers, 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 seg- ment. 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 Miller of Berlin. Some of its most important stages are repre- sented on Plates VIII. and IX. (Compare their explanation in the Appendix.) Fig. A on Plate IX. shows us a com- mon Sea-star (Uraster), Fig. B, a Sea-lily (Comatula), Fig. C, a Sea-urchin (Kchinus), and Fig. D, a Sea-cucumber (Synapta). In spite of the extraordinary difference of form manifested by these four representatives of the differ- ent classes of Star-fishes, yet the beginning of their develop- ment is identical in all cases. Out of the egg an animal-form PHYLOGENY OF STAR-FISHES. 169 develops which is utterly different from the fully developed Star-fish, but very like the ciliated larvee of certain seg- mented Worms (Star-worms and Ring-worms). This peculiar animal-form is generally called the “larva,” but more cor- rectly 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 remark- able 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 (Sipunculide), and cord worms (Nemertinz). 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.) 170 THE HISTORY OF CREATION, 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,’* 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 excel- lent state of preservation in the slates of Wiirzbach, 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 prime- val group of worms, which are most probably the ancestors of Star-fish, I call Mailed worms (Phracthelminthes, p. 150.) 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 * “Ueber ein Aequivalent der takonischen Schiefer Nordamerikas in Deutschland.” ° WORM PERSON ATION = zZ fx] o al FIRS TAR FISHES S Se ee ee ee wes ae ad Lf a Leal bs er al STAR FISHES. SECOND GENERATION. WORM STOCK. a SAN A Ura ster SN) - 6B. Comatula. x €. Echinus A D Synapta. 2>> ~ WD SeF eso ZZ 272. ae wea7rrsor SZ < For >">, 2 = > >>> — = SSS >> >>> y G MG Mie Yy SA yp (a Ae en Fine ew SF DORA re rr — — = ASSN AS SESS rN }N ASV THINS Lj # Af Lp pyl, “OY yyy, ijt ¢ orem, //// Ny Hay id 3 a | Us Pine )\ SSS SS WSS \\ SASS THE STAR-FISHES. 171 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 Comatule, 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 character- ized as being without arms (Lipobrachia), equivalent to those which ‘possess articulated arms. The first of these two classes, that of Sea-urchins (Kchinida) 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 funda- mental form of the shell itself is a pentagonal pyramid- The Sea-urchins probably developed directly out of the group eof Sea-stars. The different classes and orders of 172 THE HISTORY OF CREATION. 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 (Holothuriz). These curious sausage-shaped Star-fish manifest externally a deceptive similarity to worms. (Fig. D, Plates VIII. and IX.) The skeletal struc- tures 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 compara- tive anatomy of the Holothuriz, 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 (Arthro- toda). As has already been remarked, this tribe corresponds to Linnzus’ 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 tracheze, and may therefore appropriately be united THE ARTHROPODS OR INSECTS. 173 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 Bar 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 articu- lated 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 paleontology, comparative ana- bite oh ee 174 THE HISTORY OF CREATION. tomy, 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 ani- — mals (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 ths history of their tribe, that is, their phylogeny. Fritz Miiller, in his work, “ Fir Darwin,” which has already been referred to, has explained this remarkable series of facts in a very able manner. 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 primeval 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 dise, 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 de- tailed explanation of which is given in the Appendix. On Plate XI. we see the fully developed representatives of six Pa A Nauplius. Youth-torm of six Grab-fi S. Limmeti B. Cyclops. C. Lernacocera A. 3 eee Sos Es 3 way he he be Adult form of the same six Grab-tish. PI_X1. A. Limnetis. B. Cyclops. C. Lernacocera . D. Lepas. E. Sacculina. F. Peneus. THE NAUPLIUS LARVA. 175 different orders of Crabs, a Leaf-footed Crab (Limnetis, Fig. A c); a Stalked Crab (Lepas, Fig. D c); a Root Crab, (Sacculina, Fig. # c); a Boatman Crab (Cyclops, Fig. Bc) ; a Fish Louse (Lernzeocera, 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, ete. When, however, we look at the earliest stages, or “ nauplius,” of these six different classes, after they have crept out of the ege—those marked with corresponding letters on Plate X. (Fig. A n—F n)—we shall be surprised to find how much they agree. The differ- ent 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 Primeval Crab, which was essentially like the Nauplius of the present day. 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 (Entomos- traca). 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, 176 THE HISTORY OF CREATION, SYSTEMATIC SURVEY Of the 7 Legions and 20 Orders of Crabs, or Crustacea. . Name of a ions of the Orders of the Systema Name rustacee. Crustacee. of the Orders. all Fag L EnTomostrRaca, Lower Crustacea, or Segmented Crabs (not passing through the actual Zoéa form in youth). 1. Primeval Crabs 1. Archicarida Nauplius 7 Mrcuishiopoda ee Crabs 2. eet s: ae Gill-footed Crabs) = obites 3. Trilobita aradoxides 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 ITI. Copepoda 8. Boatmen Crabs 8. Eucopepoda Cyclops Oar-footed Crabe 9. Fish Lice 9. Siphonostoma Lernzocera IV. Pantopoda 10. No-body Crabs 10. Pycnogonida Nymphon No-body Crabs V. Pecilopoda {11. Spear-tails 11. Xiphosura Limulus Shield Crabs (12. Giant Crabs 12. Gigantostraca Eurypterus Il. MALAcostrACA, Higher Crustacea, or Mailed Crabs (passing through the Zoéa form in youth). V . Podoph- 13. Zoéa Crabs 13. Zoépoda Zoéa thalma 14, Split-legged Crabs 14. Schizopoda Mysis Stalk-eyed Mailed | 15. Mouth-footedCrabs 15. Stomatopoda Squilla Crabs 16. Ten-footed Crabs 16. Decapoda Peneus VII. Edrioph- (17. Cuma Crabs 17. Cumacea Cuma thalma 18. Flea Crabs 18. Amphipoda Gammarus MailedCrabs with (eo Wizard Crabs 19. Leemodipoda Caprella sessile eyes 20. Louse Crabs 20. Isopoda Oniscus PEDIGREE OF THE GILLED. INSECTS, 177 Isopoda | Lzmodipoda Anomura, | Amphipoda Macrura Nace ae Decapoda Stomatopoda Cumacea | | Edriophthalma ee Schizopoda Podophthalma Zoépoda Malacostraca Gigantostraca Rhizocephala Siphonostoma Xiphosuras Zoéa Cirripedize | Pectostraca __-——’/ Pecilopoda Nebalize Eucopepoda Belinures Copepoda Pycnogonida a Pantopoda Trilobita Phyllopoda Ostracoda Cladocerze | —— —_ ——EEEE——————E———— ee 4 Branchiopoda ig Nae Dal ES SRY 2 OS SEIS Ee Le ea Nauplius Archicarida (Articulated Worms) 178 THE HISTORY OF CREATION, the so-called Zoéa, which is of great importance. The order of Schizopoda, those with cloven feet (Mysis, etc.), probably originated from this curious Zoéa; 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 Cu- -macea (Cuma, ete.), 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 degenera- tion 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* (Spiders, Cen- tipedes, and Flies) did not develop until the beginning of the paleolithic 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 * The English word “Insects” might with advantage be used in the Linnzan sense for the whole group of Arthropods. In this case the Hexapod Insects might be spoken of as the Flies.—K. R. L. ORIGIN OF TRACHEA, 179 carboniferous beds, we can pretty accurately determine the time of their origin. The development of the first Tracheate Insects out of gill-bearing Zoéa-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,’ has lately endeavoured to explain the origin of the Tracheata by an ingenious hypothesis. The system of trachez, or air pipes, and the modifications of organiz- ation dependent upon it, distinguish Flies, Centipedes, and Spiders so much from other animals, that the concep- tion of its first origin presents no inconsiderable difficulties to phylogeny. According to Gegenbaur, of all living Trache- ate Insects, the Primeval Flies, or Archiptera, are most closel allied to the common primary form of the Tra- cheata. These insects—among which we may especially mention the delicate Day flies (Ephemera), and the agile dragon-flies (Libellula)—in their earliest youth, as larve, 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 larve of many primeval winged insects, must in all probability be explained as “dorsal limbs,” and as having developed out of the corresponding appendages of the Anne- lida, 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 “ tracheate gills.” The tracheate gills 180 THE HISTORY OF CREATION. 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 Mor- phology I have named Protracheata, did develop directly out of genuine Ringed worms, or at first out of Crustacea of the Zoéa form (Zoépoda, 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 Taran- tulee, they, ike 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 prob- ably very closely allied to the common primary form of the whole class; this is the order of Scorpion-spiders, or Solifugze, (Solpuga, Galeodes), of which several large species live in Africa and Asia, and are dreaded on account of their poison- ous bite. Their body consists—as we suppose to have been the case in the common ancestor of the Tracheata—of a head THE SPIDERS. 181 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 dis- tinct rings. In the articulation of their body, the Solifugee are therefore in reality more closely related to flies than to other spiders. Out of the Devonian Primeval Spiders, which were nearly related to the Solifugee 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 scor- pions, which are connected with the Solifugee through the Tarantella (or Phrynidz). The small book scorpions, which inhabit our libraries and herbariums, appear as a de- generate lateral branch from the true scorpions. Mid-way between the Scorpions and Round Spiders are the long- legged Tailor-spiders (Opiliones) which have possibly arisen out of a special branch of the Solifugee. The Pycnogonida, or No-body Crabs, and the Arctisca, or Bear Worms—still cenerally included among Long Spiders—must be completely excluded from the class of Spiders; the former belong to the Crustacea, the latter to Ringed worms. Fossil remains of Long Spiders are found in the Coal. The second sub-class of the Arachnida, the Round Spiders ‘Spheerogastres), 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 (Aranez), which we admire on 182 THE HISTORY OF CREATION, SYSTEMATIC SURVEY Of the 3 Classes and 17 Orders of the Tracheata. Sugentia . Butterflies Classes of the Sub-Classes of the Order of the Two Names of Tracheata. Tracheata, Tracheata. Generaas examples- 1. Scorpion spiders { Solpuga Solifuge Galeodes Es 2. Tarantella Phrynus Phrynida { Thelyphonus 3. Scorpions Scorpio I. es - piers Scorpioda { Buthus Spiders Arthaggustres . Book scorpions Obisinm Arachnida Pseudoscorpioda { Chelifer . Tailor spiders | Phalangium Opilionida Opilio se . Spinning spiders | Epeira Aranee Mygale ieee ans . Mites Sarcoptes Bpleragasires Acarida | Demodex II. III. 8. Simple-footed Scolopendra Centipedes Chapa : Chilopoda { Geophilus ekpatie ahi Es hae . * Dplaeta ‘E oie - iplopoda olydesmus a Pinions 0. Primitive flies Ephemera Archiptera { Libellula 1. Gauze-wings { Hemerobius Neuroptera Phryganea 2. Straight-wings Locusta Chewing Orthoptera | Forficula In. Masticantia 3. Beetles { Cicindela F Coleoptera Melolontha Flies 4. Bee-wings Apis —— Hymenoptera | Formica /15. Bugs { Aphis Hemiptera Cimex om : eee { sbi Diptera Musca Lepidoptera PEDIGREE OF TRACHEATA, Butterflies Lepidoptera oe Two-wings Hymenoptera Dunteea * Beetles tk Coleoptera Hinsilons a Gauze wings Straight-wings Neuroptera a Orthoptera | eee Primeval Flies Archiptera Scorpions Double-footed Scorpioda Diplopoda Tailor Spiders Opiliones f Book Scorpions Mites Pseudoscorpioda Acarida Tarantella : Weaving Spiders Phrynida Simple-footed Aranee Chilopoda Centipedes Myriapoda _—— Scorpion Spiders Solifugze Spiders. Arachnida Flies. Insecta Hexapoda Primary Air-breathing Arthropods Protracheata Articulated Worms Coelminthes 184 THE HISTORY OF CREATION, 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 Trache- ata, 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, ete.) 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 trachee, is that of the Flies, or Insects, in the narrow sense of the word (Insecta, or Hexapoda), the largest of all THE FLIES, OR HEXAPOD INSECTS, 185 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 ccntral divi- sion, 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 degenera- tion 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 larvee of the ephemeral flies (Ephemera) which live in water. The head of Flies universally possesses, besides the eyes, a pair of articulated feelers, or antenne, 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 26 186 THE HISTORY OF CREATION. of the class. In the first place, we may distinguish two main divisions, namely, Flies with chewing mandibles (Mesticantia) 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 primzval winged Flies, the gauzy- winged (Neuroptera), straight-winged (Orthoptera), and beetles (Coleoptera). Licking flies (Lambentia) are re- presented 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 Primeval 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 larvze which live in water, in all probability still show us in their trachez-gills the organs out of which the wings of Flies were originally developed. ‘his 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 oe THE ORDERS OF FLIES. 187 of Gauze-winged Flies (Neuroptera), probably developed directly out of the primeval 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 primeval Flies (Libellula) to the gauze-winged (Sialidz), are found even in coal (Dictyophylebia). The order of Straight-winged Flies (Orthoptera) de- veloped at an early period out of another branch of the primeval 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, ete. (Ulonata)—and of a smaller group consisting only of the well-known earwigs (Labidura), which are character- ised by nippers at the hinder end of their bodies. Fossil remains of cockroaches, as well as of crickets and grass- hoppers, have been found in coal. Fossil remains of the fourth order of Biting Fhes, 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 188 THE HISTORY OF CREATION, group of the Bees, or Skin-winged Flies (Hymenoptera), is closely allied to the four orders of biting Flies. Among them are those Fles 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 primeval Flies or the gauze- winged Flies. Of the two orders of Pricking Flies (Hemiptera and Diptera), that containing the Half-winged Flies (Hemip- tera), 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 Cicadz. 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 ORDERS OF FLIES. 189 The second order of pricking flies, namely, the Two- winyed 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 degenera- tion 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 relation- ship between some moths (Tinez) and (Noctue), 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 I90 THE HISTORY OF CREATION, 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 Primeval Crabs, or Archicaride. The form of these Primzval Crabs, which were developed out of segmented worms, is still approximately preserved by the remarkable Nawplius, in the common larval stage of somany Crabs. Out of the Nauplius, at a later period, the curious Zoéa 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 trachez, 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 Primeval 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 along period there existed only the four biting orders of Flies—the Primeval 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. Ais Flies with Chewing SElouths Masticantia B. Flies with Sucking SEouths Sugentia CLASSIFICATION OF FLIES. L Biting Flies . Mordentia II. Licking Flies Lambentia HE Stinging Flies Pungentia EV: Sipping Flies Sorbentia ‘1. Primeval winged Archiptera 2. Gauze-winged Neuroptera . Straight-winged Orthoptera 4, Beetles Coleoptera | 5. 6. Half-winged Hemiptera Skin-winged Hymenoptera 7. Tway-flies Diptera 8. Butterflies Lepidoptera MI [aA M.C. oe IQI A.A. 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). 192 THE HISTORY OF CREATION, CHAPTER XX. PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM. III, VERTEBRATE ANIMALS. The Records of the Creation of Vertebrate Animals (Comparative Anatomy, Embryology, and Palzontology).—The Natural System of Vertebrate Animals.—The Four Classes of Vertebrate Animals, according to Lin- nzeus 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 Em- bryological Development of Amphioxus and Ascidiz.—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 (Primeval Fish, Cartilaginous Fish, Osseous Fish).—Mnud-fish, or Dipneusta.—Sea Dragons, or Halisauria.—Frogs and Salmanders, 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 distin- guished from that of other Vertebrate animals. But as trom PHYLOGENY OF VERTEBRATES, 193 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 paleontological 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 paleontology, and Bar’s ontogeny of the Vertebrate animals, had braqught us to a high level of accurate knowledge on this matter. Since then it is especially due to Johannes Miiller’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 Gegen- baur’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. 194 THE HISTORY OF CREATION. Here, as everywhere else, analogies must be traced to Adapta- tion, 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 agree- ment and homology by the supposition of a common trans- mission 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 pedi- gree 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 Il. and III, is a fact of incalculable importance, and furnishes us with the most important data for the construction of their pedigree, CLASSES OF VERTEBRATA, 195 Finally, the paleontological 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 organiza- tion. 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, Linnzeus’ four higher classes of animals, viz. Mammals, Birds, Amphibious animals, and Fishes. Linnzeus’ two lower classes, Insects and Worms, Lamarck contrasted to the Vertebrata as Invertebrata, later also called Hvertebrata. 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 Bar did almost at the same time from the ontogeny of Vertebrata—that Linnzeus’ 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, 196 THE HISTORY OF CREATION. Salamanders, gilled Salamanders, Ceecilia, 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, ete. 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 appro- priately be called Gill-less, or Vertebrata with lungs (Abranchiata, or Allantoida). However correct this dis- tinction may be, still we cannot remain satisfied with it if we wish to arrive at a true natural system of the verte- brate 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 lanceola- tus). Nearly allied to this is the second class, that of the Single-nostriled animals (Monorrhina), or Rouwnd-mouthed LARGER GROUPS IN THE VERTEBRATA. 197 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 transi- tion 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 dis- 198 THE HISTORY OF CREATION, tinguish 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 ‘e Round-months 2. Cyclostoma B. Monorrhina Animals with 3. Fish 3. Pisces Skulls b. Donble{ 1: Non- |4. Mud-fish 4. Dipneusta (Craniota) nostriled | A™nionate +5. Sea-dragons 5. Halisauria or animals Anamnia 1/6, Batrachians 6. Amphibia Thick Hearts | Amphir- (Pachycardia) rhina II. Amnion- (7. Reptiles 7. Reptilia ate. . Birds 8. Aves Amniota \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 THE AMPHIOXUS. 199 of all the Vertebrate animals known tous. 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-trans- parent. 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. Butstill 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 cen- tral 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), like- wise 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 200 THE HISTORY OF CREATION, 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 repre- sented 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 con- tractions 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). 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 larve of the 5 deg hd ae oP ela ee Sm y ws DAN | “Ate a ’ ALP i. Le ‘ , oe , a, Fs 5 ee oa , ; i ' r pee fa 7 Vs s . ij / ' ’ ’ » i, aS, 7 , . j i q " ‘ 4 ¢ i r af r 2 ta i af Sa a \ n r ' : ‘ ’ he Wi ' : ies hay a7 Ob Le : 7 bere ‘ fat htt, bg S| Ae : s 3 i a Ascidia (A) and Amphioxus (B, ASCIDIANS RELATED TO VERTEBRATES, 20! Ascidians (Plate XII. Fig. A) develop the undeniable begin- ning of a spinal marrow (Fig. 5 g) and of a spinal rod (Fig. 5 ¢), 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 shape- less lumps, which when looked upon externally would scarcely be supposed to be animals. (Plate XIII. Fig. 4.) 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 character- istic 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 retro- grade 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 repre- sented only by the Hags (Myxinoida) and Lampreys (Petromyzonta). This class also, on account of the absence 202 THE HISTORY OF CREATION. 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 Rownd-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 dis- tinguished 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 - > 1 3 ” WN THE LAMPREYS AND HAGS. 203 separating the Monorrhina, as we have separated the Skull- less animals, from the Fishes, with which they have hitherto been erroneously classed. We owe our first accurate knowledge of the Monorrhina, or Cyclostoma, to the great zoologist, Johannes Miiller 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 (Petro- myzon 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. 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 204 THE HISTORY OF CREATION, 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-eless (Acrania), or Tube-heartey (Leptocardia). Vertebrata without head, without skull and brain, without centralized heart. 1. Skulleless I. Tube-hearted tI. ee 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. Sub-classes of the Classes of the Skulled Animals, Main-classes Systematic Name of the Skulled h of the Animals. Skulled Animals. Sub-classes. 2. Single: 2. Hags, or Mucous 2. Hyperotreta cw ingit- | II. Round mouths Fish (Myxinoida) Posteiley } Cyclostoma 3. Lampreys, or 8. Hyperoartia Monorrhina Pride (Petromyzontia ) Ill. Fish 4, Primeval fish 4. Selachii Pisces | 5. Ganoid fish 5. Ganoides 6. Osseous fish 6. Teleostei IV. Mud-fish ‘ ae { 7. Mud-fish 7. Protopteri 3. Pon-am- 8. Primeval 8. Simosanria muonate V. Sea-dragons dragons Anamnion- Halisauri 9. Snake-dragons 9. Plesiosauria ata 10. Fish-dragons 10. Ichthyosauria 11. Mailed Batra- 11. Phractamphibia VI. Batrachians chians Amphibia 2. Naked Batra- 12. Lissamphibia chians 3. Primary reptiles 13. Tocosauria 4, Lizards 14. Lacertilia 5. Serpents 15. Ophidia 6. Crocodiles 16. Crocodilia 7. Tortoises 17. Chelonia 8. Flying reptiles 18. Pterosauria 4. Amnion 9. Dragons 19. Dinosauria Animals 0. Beaked reptiles 20. Anomodontia Amni a . Long-tailed 21. Saururze pees i Paedieds Fan-tailed 22. Carinates 3. Bush-tailed 23. Ratitz 4, Cloacal animals 24. Monotrema oe 5. Pouchedanimals 25. Marsupialia 6. Placental animals 26. Placentalia PEDIGREE OF VERTEBRATES, 205 9. Mammals Mammalia 8. Birds Aves 7. Reptiles Reptilia 5. Sea-dragons | Halisauria —.-——- Osseous fish Amnion Animals Teleostet 4. Mud-fish Amniota Dipneusta Ganoid fish 6. Batrachians Ganoidet Amphibia a ie lene Loo Vertebrate animals breathing through limgs Amphipneumones Eg pe es Se Primeval fish Selachii 3. Fishes Pisces Double-nostriley Amphirrhina 2. Round-mouthed Cyclostoma aetna SRO 45 TA Be Single-nostriley | Monorrhina Animals with skulls Craniota 1. Tube-hearted Leptocardia m As Cc id ie —”?—_l.I Eee ESO Sea-barrels Skulleless Animals Thaliacea Acrania | Pertebrate Animals Vertebrata CC TicnuateAnimals Tunicata - 206 THE HISTORY OF CREATION. 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 Ceecilize 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 primeval fish, or Selachii, to which the Proselachit. 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 PRIMAVAL FISH. 207 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. Genuine fish are divided into three distinct sub-classes, namely, Primeval fish, Ganoid fish, and Osseous fish. The oldest of these, where the original form has been most faithfully preserved, is that of the Primeval fish (Selachii), Of these there still exist Sharks (Squali), and Rays (Rajz), which are classed together as cross-mouthed fishes (Plagiostomi), and the strange and grotesquely formed Sea- cats, or Chimcracet (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 palzeolithic period. Unfortunately all Primzval 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 208 THE HISTORY OF CREATION. SYSTEMATIC SURVEY Of the 7 Legions and 15 Orders of the Fishes. Sub-classes Legions Orders Examples Fishes. Fishes. Fishes. the Orders. (etre ee . Sharks Sharks, dog-fish et i Squalacet gel Plaginstoas 2. Rays Spiked rays, electric Sish Rajacer rays, etc. Selachii Z| II. Sea-Cats 3. Sea-Cats Chimera, Calorrhyn- Holocephah Chimeracet chias 4, Buckler-heads Cephalaspide, Placo- Te. my y Gancyd Pamphracte derma, etc. dani ; 5. Sturgeons Spoon-sturgeons, stur- hic Sturiones geons, sterlet, etc. RB. fa Pa A a 6. Efuleri Doula Ganoid es a 7. Fuleraté er bony pike, etc. el Barer gers 8. Semcoptert African finny pike, etc. ¥. .Bound-scaled 9. Caloscolopes Holoptychius, Coelacan- Ganoid Fish thides, etc. Cycliferi 10. Pycnoscolopes Coccolepida, Amiade, etc. VI. Osseous Fish a ay ge 11. Herring species Herrings, salmon, carp, passage to the Thrissogenes etc. eenanche 12. Eel species Eels, snake eels, electric Beh 1 bladder | Enchelygenes eels, etc. Fish Physostome Teleostei VII. Osseous Fish /13. Stichobranchit Perch, wrasse, turbot, without an air etc. passage to the fa Plectognatht Trunk fish, globe fish, swimming etc. bladder 15. Lophobranchit Pipe fish, sea horses, Physoclisti etc. PEDIGREE OF THE NON-AMNIONATE CRANTIOTA, 209 Plectognathi Anura | Lophobranchia Peromela Sozura a ai ee Labyrinthodonta Stichobranchia Physoclisti NS _ ra Enchelygenes Ganocephala § Sozobranchia Phractamphibia Lissamphibia es Thrissogenes Amphibia Physostomi Semzeopteri Teleostei Protopteri Falcrati Plesio- sauria Pycnoscolopes Ichthyo- sauria Cceloscolopes Efuleri Cycliferi Rhombiferi (Cycloganoides) (Rhomboganoides) Dipneusta . Placoderma Simosauria Sturiones Halisauria Cephalaspidze Rajacei Amphipneumona Pamphracti Tabuliferi (Placoganoides) Chimeeracei Ganoides Holocephali Squalacei Plagiostomi 5 a eS eee 27 Selachii Fish Amphirrhina Cyclostoma Monorrhina Craniota 210 THE HISTORY OF CREATION. 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 develop- ment of Primzeval 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 Primeval 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 Primzeval fish, in all prob- ability, 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 Primeval 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 Primeval to Osseous fish. The Ganoids are for the most part extinct, and more nearly so than the Primeval fish, whereas they were developed in great force during the entire palzeolithic 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 GANOID AND BONY FISH. 21 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 (Spatularide), and those Sturgeons (Accipenseridz) 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 paleolithic 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 Mesolithie epoch out of Ganoid fish,and moreover out of the Round-scaled, or Cycliferi. 23, ie THE HISTORY OF CREATION, The Thrissopide 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, ete. further, the Lock-jaws (Plectoonathi), 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) es THE DIPNEUSTA. 213 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, ete—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 character- istics 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 Monor- rhina and the Leptocardia. However, teeth are found in the Trias which resemble those of the living Ceratodus. Possibly the extinct Dipneusta of the palzeolithic period, which developed in the Devonian epoch out of primeval 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 Primeeval fish to Amphibia—were probably very like the Dipneusta. 214 * THE HISTORY OF CREATION, 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 pre- served 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, differ- ing 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 jive 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 Primeval fish. On the other hand, they breathed air through lungs, ike the Dipneusta, although they always swam about in the sea. They, - “eS THE SEA-DRAGONS, 215 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, Primevel Dragons, Fish Dragons, and Serpent Dragons. The Primeval 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 Ichthyosauriaa 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 216 THE HISTORY OF CREATION, 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 Primeval 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 Primeval 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 adapta- tion. 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 THE SALAMANDERS, 217 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 Cecilie (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 de- velopment 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, 218 THE HISTORY OF CREATION. however, they differ externally by the absence of the coat of scales. Most gilled Batrachia ive 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. 1. 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- lie 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. THE AMNION-SAC. 219 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 fetal membrane, or amnion, which commences at the navcl, 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 character- istic formation, we may comprise the three most highly developed classes of Vertebrata under the term Ammnion- 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 anvnion-less animals (Anamnia). The formation of the fcetal 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 220 THE HISTORY OF CREATION, opposed to all other Vertebrate animals which breathed through gills (Branchiata). In all the Vertebrata 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 Amnioticanimals the base of the skull appears bent in on the abdominal side, so that the head sinks upon the breast. (Plate IIT. 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 THE TRIASSIC PERIOD. 221 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 paleeolithic fern forests were then re- placed by the pine forests of the Trias period; important transformations then took place in many of the classes of Invertebrata. Articulated marine lilies (Colocrina) de- veloped out of the plated ones (Phatnocrina.) The Autechi- nidz, or sea-urchins with only twenty rows of plates, took the place of the palzeolithic Palechinidze, the sea-urchins with more than twenty rows of plates. The Cystidez, Blas- toidez, Trilobita, and other characteristic groups of Inverte- brata of the primary period became extinct. It is no wonder that transforming conditions of adaptation power- fully influenced the Vertebrate tribes also in the beginning of the Trias period, and caused the orig:n 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 conse- 222 THE HISTORY OF CREATION. quently 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 mid-way 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 uni- versally 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 Ee a rn Fs, A rar , ff ay > eee - ostrilled or Amphirrhina ion, without gills. re ao | a eee A A An | Vi ul i ik ar i a iy | q H | I } << == => SS —— SS SSS so 8 = SS —— eae SSS —— a y) 0 ! fh, ( \ i NNN mi iN ( \ ( A) \ Ml Mi iW i} NV (i ik | \ iit MN) i aa MH \ ) ie Wi NK ) My fh ANU " i .: 4 SS 1 Relative lengths of the 5 Singl wad Epochs in per centages. MONOPHYLETIC PEDIGREE Quarternary Epoch ...0.5 of the Stem of the Tertiary Epoch. Liociuamaten’ Didehee Seco. BACK-BONED ANIMALS based on Paleontology. Primordial Epoch..53.6 _ Archilithic. or Primordial Epoch. en ee RECENT AND FOSSIL REPTILES, 223 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 fossil even in the Jura and Trias periods. 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 Primeval 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). 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 224 THE HISTORY OF CREATION. SYSTEMATIC SURVEY Of the 8 Orders and 27 Sub-orders of Reptiles. - (Those groups marked with * became extinct even during the Secondary Period.) ae Sub-orders Systematic Name A Generic Name of Reptiles. hie d of the - eptiles. Sub-orders. an example. I. #rimary 1 Primeval rep- 1. Proreptilia * (Proterosaurus? Reptiles tiles Tocosauria 2. 2. Thecodontia * Paleosaurus 3. Cleft-tongued 3. Fissilingues Monitor Il. DLisards 4, Thick-tongued 4. Crassilingues Iguana Lacertilia 5. Short-tongued 5. Brevilingues <= 6. Ringed lizards 6. Glyptodermata Amphisbeena 7. Chameleons 7. Vermilingues Chameleo 8. Adders 8. Aglyphodonta Coluber 9. Tree serpents 9. Opisthoglypha Dipsas Tit. Serpents 10. 10. Proteroglypha Hydrophis pate 11. Vipers 11. Solenoglypha Vipera 12. Wormserpents 12. Opoterodonta Typhlops IV. Croco. ( 18. Amphiccela 13. Teleosauria * Teleosaurus Viles 14, Opisthoccela 14. Steneosauria * Steneosaurus Crocodilia 15. Prosthocela 15. Alligatores- Alligator 16. Sea tortoises 16. Thalassita Chelone V. Tortoises | 17. Rivertortoises 17. Potamita Trionyx Chelonia 18. Marshtortoises 18. Elodita Emys 19. Land tortoises 19. Chersita Testudo : 20. Long-tailed 20. Rhampho- * Rhampho- eg aeoes Flying lizards rhynchi rhynchus epiiltS | 21. Short-tailed 21. Pterodactyli © * Pterodactylus Pterosauria * Costas Flying lizards 22. Giant dragons 22. Harpagosauria * Megalosaurus VII. Dragons : . ; * . 23. Elephantine $23. Therosauria Iguanodon Dinosauria * seal ons 24. Dog-toothed 24. Cynodontia * Dicynodon VIII. %rakery | 25- Toothless 25. Cryptodontia * Udenodon Reptiles 26. Kangaroorep- 26. Hypsosauria * Compsognathus Anomodontia * tiles 27. Bird reptiles 27. Tocornithes * (Tocornis) > BIRD-LIKE REPTILES. 225 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 re- markable group of Tortoises (Chelonia); fossils of these strange animals are first met with inthe 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 re- semblance 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 elon- gated 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 Rham- phorhynchia and of the short-tailed Pterodactyle 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). 226 THE HISTORY OF CREATION. 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 forthe 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 THE REPTILE-LIKE BIRD. 22% Mammals, are still scarcely distinguishable from those of Tortoises and other Reptiles. The cleavage of the yoll 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 these 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 (Archeopteryx). 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 Tocor- nithes 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 228 THE HISTORY OF CREATION. formation of their beaks and feet—are of an exceeedingly 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 (Saururee) and those of the ostrich kind, which differ considerably from the usual type of bird, namely, from those with keel-shaped breasts (Carinatze), and hence the whole class may be divided into three sub-classes. The first sub-class, the Reptile-tailed, or Feather-tailed Birds (Saurure), 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 Primeval Griffin, or Archzopteryx lithographica, of which as yet only one speci- men 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 unfortun ately 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 vertebre ; the last of these have grown together into a thin, bony plate standing perpen- dicularly, upon which the rudder-feathers of the tail are attached in the form of a fan. The Archzeopteryx, however, has a long tail like a lizard, composed of numerous (20) long thin vertebrz, and on every vertebra are attached the SUB-CLASSES OF BIRDS. 229 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 Archzeopteryx 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 (Carinate), which form the second sub-class, comprise all living Birds of the present day, with the exception of those of the ostrich kind, or Ratitz. 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 vertebree 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 (Ratitze), 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 (pyornis) and the New Zealand Dinornis, which were much larger than the 230 THE HISTORY OF CREATION. 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 XXL PEDIGREE AND HISTORY OF THE ANIMAL KINGDOM. IV. MAMMALS. The System of Mammals according to Linneus 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.—Dise 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 Ani- mals.—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 232 THE HISTORY OF CREATION, morphological point of view, belongs to the class of Mam- mals. 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 Linnzus distinguished the following eight orders: (1) Cetz (whales); (2) Belluze (hippopotami and horses) ; (3) Pecora (ruminating animals) ; (4) Glires (gnawing animals and rhinoceroses) ; (5) Bestiz (insectivora, marsupials, and various others); (6) Ferz (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 Linneus. 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 — Lanes eee 4 THE CLOACAL MAMMALS. 233 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 (Pro- mammalia). 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 rolar teeth. These have been found in the upper- most strata of the Trias, in the Keuper, first in Ger- 28 234 THE HISTORY OF CREATION. many (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 ease, 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 Mono- delphia) 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 (m:man about the twelfth week of develop- ment). The Cloacal animals have also been called “ Forked animals,” because the collar-bones, by means of the breast CHARACTERS OF MONOTREMA, 235 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 con- nected 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 dis- tinguishes 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 236 THE HISTORY OF CREATION. 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 Marsu- pialia), 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, poucLed 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 Marsu- pials 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. THE POUCHED MAMMALS. 237 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 238 THE HISTORY OF CREATION. in the two sub-classes of Marsupials. According to this, about eight orders of Marsupial animals may be dis- tinguished, 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. Of Herbivorous marsupials (Botanophaga), only two fossils are as yet known from the Jura, namely, the Stereo- enathus 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 hving Marsupials. The Diproto- don Australis, whose skull alone is three feet long, exceeded even the river-horse, or Hippopotamus, in size and upon the ——— ORDERS OF POUCHED MAMMALS. 239 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 fAammals Promammalia II. Beaked Animals Ornithostoma Unknown extinct Mammalia from the Trias Period 1. Aquatic beaked animals 2. Terrestrial beaked animals 1. Ornithorhyn- chida 2. Echidnida ( (Microlestes 7) (Dromatherium ?) 1. Ornithorhynchus paradoxus {2. Echidna hystrix II. Second Sub-class of Mammalia: Pouched or Marsupial Animals (Marsupialia, or Didelphia). Mammals without Cloaca, without Placenta, with Marsupial Bones. 8. Ape-footed Marsupial animals (Pouched animals 8. Pedimana 2). . Chironectida Didelphyida cans Saget ae pha Sesicke' 3 Name Families of the Marsupialia. Marsupialia. the Orders. Marsupiatia. 1. Hoofed 1. Barypoda 1, Stereognathida Marsupial animals 2. Nototherida ae 3. Diprotodontia : 2. Kangaroo 2. Macropoda : : Perbivorous Marsupial animals 4. Plagiaulacida : (Leaping pouched 5. Halmaturida falarsupial animals) 6. Dendrolagida Animals 3. Root-eating 3. Rhizophaga Marsupial animals Marsupialia (Gnawing a : 7. Phascoiomyida animals) Botanophaga 4, Fruit eating 4. Carpophaga & Phasrolarethia Marsupial animals : RSE (Climbing pouched 9. Phalangistida aniinats) 10. Petaurida : ti 3 h z Mapsupial animals (he ansiecatherige (Primeval pouched 13. M ‘ d . Myrmecobida “~ animals) Es Peramelida Carnivorous 6. Marsupialanimals 6. Edentula ; poor in teeth 15. Tarsipedina felarsupial (Pouched animals : P Animals with trunks) 7. Rapacious marsu- 7. Creophaga ‘ Marsupialia deen cotta + Pe acter = (Rapacious pouched 18. Thylacoleonida Zoophaga animals) with hands) 240 THE HISTORY OF CREATION. SYSTEMATIC SURVEY OF PLACENTAL ANIMALS. Ill. Third Sub-class of Mammalia: Placentalia, or Monodelphia (Placental Animals). Mammals without Cloaca, with Placenta, without Marsupial Bones. Legions of Orders of the the Placental Animals.| Placental Animals. Til. 1. INDECIDUA. Sub-orders of the Placental Animals. Systematic Name of the Sub-orders. Placental Animals without Decidua. peas mated { ae Perissodactyla . Horses Hoatey ‘animats | ju Double-hovfed { 3. Pigs Ungulata ‘Artiodactyla 4. Ruminating III. Herbivorous ( Conese 5. Sea cows hycoceta avi hates IV. Carnivorous 6 Whales Cetacea anne 7. Zeuglodonta V. Digging et 8. Ant-eaters a. Effodientia 9. Armadilloes poor in teeth VI. Sloths { 10. Glant Sloths Edentata Bradypoda Dwarf Sloths or wwnDre a 1) =) HS © . Tapiromorpha . Solidungula . Choeromorpha . Ruminantia . Sirenia . Autoceta . Zeugloceta Vermilinguia Cingulata . Gravigrada . Tardigrada Ill. 2. DEcIDUATA. Placental Animals with Decidua. VII. Rapacious 12, — land ees Animals 13 Ray car soa sea , * a Ilacental Ani- Carnaria parE mals. Hyrax : VIII. False-hoofed Zonoplacentalia Animals {i oe Che.ophora : 17. Elephants 18. Fingered ani- mals / IX. Semi-apes 19. Flying lemur Prosimie 20. Long-footed 21. Short-footed 22. Squirrel species X. Gnawing Ani- | 23. tis species al 24, Porcupine spe- eee 25. Hare species XI. Insect-eating (26. With a Cecum Discoplacentalia Animals {2 27, Without a Ce- Insectivora cum XII.Flying Animals { 28. Flying foxes Chiroptera V 29. aves & 30. Clawed apes ee | 31, Flat-nosed 32. Narrow-nosed 12. Carnivora . Pinnipedia . Lamnungia . Toxodontia - Gonyognatha . Proboscidea . Leptodactyla . Ptenopleura - Macrotarsi . Brachytarsi . Sciuromorpha Myomorpha . Hystrichomorpha . Lagomorpha . Menotyphla Lipotyphla . Pterocynes . Nycterides . Arctopitheci . Platyrrhine . Catarrhine bp itn ct i PEDIGREE OF THE MAMMALITA, 241 félan Elephants res Proboscidea | Bats Rock Conies Nycterides Lannungia Narrow -nosed Mari at Catarrhine ae Pakale : te prey Flying foxes Mater: 0K —— Flat-nosed Pterocynes Pseudo-hoofed Platyrrhine Flving Animals Chelophora Chiroptera —— ; Land animals of prey Apes Carnivora Gnawing Animals - Simie Animals of Jrep Rodentia Carnaria | Fingered animals Lemurs Leptodactyla Brachytarst | True a whales Insect eaters Sarcoceta ales ark AE ee Insectivora Sea cows Semi-apes Sirenia Prosimie CA hales Deciduous Animals ~ Cetacea Deciduata | Poor in teeth Edentata Woofer Animals Ungulata — Enveciduous Indeciduata i Placental Animals Placentalia Herbivorous marsupials { Carnivorous marsupials Marsupialia botanophaga | Marsupiaha zoophaga fHarsupial Marsupialia Beaked animals | Ornithostoma | Primary mammals Promammalia Cloacal Animals Monotrema 242 THE HISTORY OF CREATION. 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, how- ever, resembles that of horses, and their complex stomach that of Ruminants.