See BENE SON rn eon SORE wick he itn ene Ronis ses we “ a 8 Wan te: ie ik eae Lan re th gee SSSA supra teria Pibrary of the Museum COMPARATIVE ZOOLOGY, AT HARVARD COLLEGE, CAMBRIDGE, MASS. The gift of °/ Biya iS, Xs Nous Maniel Denison Slade. 4 Se wgcinga Stee = vane MANUAL OF PALHONTOLOGY A MANUAL OF’ PALAONTOLOGY FOR THE USE OF STUDENTS WITH A GENERAL INTRODUCTION ON THE PRINCIPLES OF PALHONTOLOGY BY HENRY ALLEYNE NICHOLSON M:.D., D:Sc., Po. D., F-R.S.H., F:G.S., &e. PROFESSOR OF NATURAL HISTORY IN THE UNIVERSITY OF ST ANDREWS SECOND EDITION REVISED AND GREATLY ENLARGED EN EWO, VOLS: WOT IE. WILLIAM BLACKWOOD AND SONS EDINBURGH AND LONDON MDCCCLXXIX All Rights reserved : e fs : YRAR eT : VLOIUON G08 un Pil SHON AS CONTENTS OF THE SECOND VOLUME. PART I1.—PALAOZOOLOGY (Continued). CHAPTER XXIV. PAGE General characters of the Gasteropoda—Shell of the Gasteropods— Siphonostomatous and Holostomatous Univalves—Table of the divisions of the Gasteropoda—General distribution of the Gas- teropoda in time—Strombide—Muricide—Buccinidee—Conidee Volutidae—Cy preeidee—N aticidee—Pyramidellidee— Cerithiadee —Melaniadee—Turritellidee—Littorinidee—Paludinidee—N erit- idee — Turbinidee — Haliotidee—Fissurellidae — Calyptreeidee— Patellidee — Dentalidee—Chitonidee — Opisthobranchiate Gas- teropods— Tornatellidee — Bullidge — Aplysiadze —Pleurobran- chide, : : : : F : : 2 : : 1-37 CHAPTER XXYV. Heteropoda—Firolidee—Atlantide—Pulmonate Gasteropods—Heli- cidee — Limacidee— Limneeidee— Auriculidee—Cyclostomidee— Aciculide, ; ’ ; ‘ : : : : : 38-46 CHAPTER XXVI. General characters of the Pteropoda—General distribution of the Pteropoda in time — Hyalea— Theca — Conularia — Tenta- culites, : : : : E : ; : : 3 47-52 CHAPTER XXVIL General characters of the Cephalopoda—Mandibles of the Cephalo- pods—Ink-sac, shel], and internal skeleton—Divisions—General V1 CONTENTS. distribution of the Cephalopoda in time—General characters of the Tetrabranchiata—Anatomy of the Pearly Nautilus — Shell of the Tetrabranchiata—Distribution of the Tetrabranch- iata in time—Nautilide—Orthoceratide—A mmonitide—Shell of the Ammonitide—Distribution in time of the Ammonitide —Genera of the Ammonitide, . ; : : ; ; 53-86. CHAPTER XXVIII. General characters of the Dibranchiate Cephalopods—Distribution General characters of the Vertebrata of the Dibranchiata—Octopoda—Argonautide—Octopodide— Decapoda — Teuthidee —Sepiadee—Spirulidee—Belemnitidee— Literature of Mollusca, . : : : : : . 87299 CHAPTER XXIX. General structure of the Vertebrate skeleton—Classes of the Vertebrata—General dis- tribution of Vertebrata in time, : : ; , . 100-108 CHAPTER XXX. General characters of the Fishes—Scales of Fishes—Skeleton of Fishes—Limbs of Fishes—Median fins of Fishes—General dis- tribution of Fishes in time—Conodonts, . : : . 109-123 CHAPTER XXXI. Teleostean and Ganoid Fishes— General characters of the Teleostei —Sub-orders of the Teleostei—Malacopteri — Anacanthini— Acanthopteri — Plectognathi—Lophobranchii—General charac- ters of the Ganoidei—General distribution of the Ganoids in time—Classification of the Ganoids—Amiadee—Lepidosteidae— Platysomidze— Crossopterygidee—Families and distribution of the Crossopterygious Ganoids — Acanthodidee — Ostracostei — Chondrosteide, . ; : : : 2 : : . 124-151 CHAPTER XXXII. Elasmobranchii and Dipnoi-—General characters of the Elasmo- branchii—General distribution of the Elasmobranchii in time —Holocephali—Plagiostomi, general characters and divisions of Cestraphori—Cestracionts of the Upper Ludlow Rocks—Hybo- donts and Acrodonts—Selachii—Batides—General characters of the Dipnoi—Characters of Ceratodus—Dipterus—Paleichthyes of Dr Giinther—Literature of Fishes, : ; : » | 152-172 CONTENTS. CHAPTER XXXIII. Amphibia—General characters of the Amphibia—Distribution of Amphibians in time —Urodela — Anoura — Labyrinthodontia — Classification of Labyrinthodontia — Literature of Am- Vil phibia, : ; : : : : 2 g . 173-186 CHAPTER XXXIV. Reptilia—General characters of Reptiles—Distribution of Reptiles —Characters and geological distribution of the Chelonia— Ophidia—Lacertilia—Crocodilia, : : : . 187-213 CHAPTER XXXV. Extinct orders of Reptiles —Characters and distribution of the Ichthyopterygia — Sauroptery gia — Pterosauria — Anomodontia —Deinosauria—Theriodontia— Literature of Reptiles, . 214- CHAPTER XXXVI. General characters of the Birds—Skeleton— Pectoral limbs—Hind- limbs—General distribution of Birds in time—Footprints of 241 the Connecticut Trias, : i , : , : . 949-953 CHAPTER XXXVII. Sub-classes and orders of Birds—General characters and geological history of the Cursores— Natatores— Grallatores — Rasores— Scansores—Insessores—Raptores — Saururee — Odontotormee— Odontolcze—Literature of Birds, : , : » 25422972 5 CHAPTER XXXVIII. General characters of Mammals—Osteology of Mammals—Limbs— Teeth—General distribution of Mammals in time, . . 273-285 CHAPTER XXXIX. Orders of Mammalia—-Characters and distribution of Monotremata ‘—Marsupialia, . . : ; . : : . 286-298 CHAPTER XL. Orders of Mammalia continued—Characters and distribution in time of the Edentata, 5 : : : . ‘ . 299-307 Vill CONTENTS. CHAPTER XLI. Orders of Mammalia continued—Characters and distribution in time of the Sirenia—Cetacea—Balenidaee—Catodontidaee—Del- phinidee—Rhynchoceti—Zeuglodontide, . : : . 308-317 CHAPTER XLII. Orders of Mammalia continued—Characters and distribution of the Ungulata—Perissodactyle Ungulates—Cory phodontia—Rhino- ceridze — Tapiridee — Brontotheride — Paleeotheridee — Macrau- chenidee—Equide, ; : : : : : . 318-340 CHAPTER XLIII. Orders of Mammalia continued—Hippopotamide—Suida—xXipho- dontidee — Anoplotheride — Oreodontidee Ca- melidee — Tragulidee — Cervidee — Camelopardalidee — Cavi- cornia, ‘ : . ‘ : , : : é . 341-369 Ruminantia CHAPTER XLIV. Orders of Mammalia continued—Characters and distribution in time of the Dinocerata—Tillodontia—Toxodontia, . 370-376 CHAPTER XLV. Orders of Mammalia continued—Characters and distribution in time of the Hyracoidea—Proboscidea—Elephas—Mastodon— Deinotherium, . : ; . 2 F 4 ; . 377-389 CHAPTER XLVI. Orders of Mammalia continnued—Characters and distribution in time of the Carnivora—Pinnigrada—Plantigrada—Urside—Melide —Digitigrada— Mustelidee—Viverridee—Hyenidee—Canidee— Hyenodontide—Felide, . : . ; ; , . 390-403 CHAPTER XLYVII. Orders of Mammalia continued—Characters and distribution in time of the Rodentia—Leporide—Lagomyda—Cavide—Hys- tricidee—Cercolabidee—Octodontidee—Chinchillidee—Castoridee —Muride —Dipodidee—My oxidee— Sciuridee—Characters and (listribution in time of the Cheiroptera — Characters and dis- tribution in time of the Insectivora—Talpidee—Soricidee— Erinaceide, : : : . : 2 : . . 404-415 CONTENTS. 1X CHAPTER XLVIII. Orders of Mammalia continned—Characters and distribution in time of the Quadrumana—Strepsirhina—Platyrhina—Cata- rhina—Characters and distribution in time of the Bimana— Literature of Mammalia, . : : : : 4 . 416-426 PART II.—PALA/OBOTANY. CHAPTER XLIX. Paleobotany —— Divisions of the Vegetable Kingdom — General relations of Plants to time, : : ‘ : . 429-439 CHAPTER L. Pre - Carboniferous Floras—Cambrian Plants—Silurian Plants— Devonian Plants, : : s . ; : ; . 440-450 CHAPTER LI. Carboniferous Plants—Origin and structure of Coal—Ferns—Cala- mites — Calamodendron — Lepidodendroids — Sigillarioids — Coniferae — Cycadacezee —Angiospermous Exogens — Monocoty- ledons—Permian Plants, . : : ; : : . 451-464 CHAPTER LII. Floras of the Secondary and Tertiary periods—Triassic Plants— Jurassic Plants—Cretaceous Plants—Eocene Plants—Miocene Plants—Plioocene Plants, . : : ; : ; . 465-476 GLOSSARY, : : : : : ‘ ; : . 477-505 INDEX, : : : P 2 , : ; : 2 OOG=Dail leva\dayal edit. PAT) AO ZOO GO G ¥ (CONTINUED) Lit ATO Ve Vol. IL, pages 134 and 138. The reader will kindly delete “ Platysomide ” from the list of swb-orders of Ganoids, and place these fishes next after the Paleoniscidee as a family of Lepidosteide. The author regrets that, having had only a hurried glance over the proof-sheets of his friend’s paper on the Platysomide, he has, through inadvertence, made the erroneous statement (p. 138, foot- note), that the elevation of the Platysomide to the rank of a distinct sub-division of Ganoids is in accordance with the views of Dr Traquair. On the contrary, Dr Traquair holds that the Platysomide constitute a family, very distinct from the Pycno- dontide, but closely allied to the Paleoniscide, and that the position of both Paloniscidee and Platysomide is rather in the sub-order Acipenseroidei. 7 Aa 14-~ -2y bt dah hee ee oe ere oo oe oy In their habits the Gasteropods show great differences, most of them being free and locomotive, though some are sedentary. The typical forms move about more or less actively by the successive contractions and expansions of a muscular organ developed upon the ventral surface of the body and known as the “foot.” In many cases the posterior VOL. II. A ~ PATA OWN 20h 0) Gey. CHAPTER XXIV. GASTEROPODA. THE Gasteropods are Molluscs in which the body is furnished with a distinct head, and the mouth rs provided with a masti- catory apparatus or “lingual ribbon.” Locomotion rs effected by means of a broad, horizontally-flattened, ventral disc—the “ foot’ —or by a vertically-flattened, fin-like modification of the same. The body is never included in a bivalve shell; and may be naked. Usually, however, there is a “univalve” shell, or om some cases a “ multiwalve” shell. This class includes all those Molluscous animals which are commonly known as “ Univalves,” such as Land-snails, Sea- snails, Whelks, Limpets, &e. In the Chitons, however, the shell is composed of eight pieces (“ multivalve”); and in the Slugs the shell is minute and completely concealed in the mantle; whilst in the Sea-slugs and Sea-lemons the animal is “naked,” and is destitute of a shell. In their habits the Gasteropods show great differences, most of them being free and locomotive, though some are sedentary. The typical forms move about more or less actively by the successive contractions and expansions of a muscular organ developed upon the ventral surface of the body and known as the “foot.” In many cases the posterior VO Ll: A 2 GASTEROPODA. portion of the foot secretes a calcareous, horny, or fibrous plate, which is called the “operculum” (fig. 382, 0), and which serves to close the aperture of the shell when the animal is retracted within it. Lastly, in one aberrant group of the Gasteropods (Heteropoda) the animal is fitted for swim- ming in the open ocean, by the conversion of the “ foot” into a vertically-flattened fin. The respiratory process in the Gasteropods differs con- siderably in different cases; and the class may be divided Fig. 382.—Ampullaria canaliculata, one of the Apple-shells, 0, Operculum ; s, Respiratory siphon. into two principal sections, according as the animal is fitted for breathing air directly or through the medium of water. The air-breathing Gasteropods are known as the Pulmonata or Pulmonifera, and comprise forms which either live on land (Snails, Slugs, &c.), or which inhabit fresh water (Pond- snails, &c.) The water-breathing Gasteropods are mostly provided with distinct gills or “ branchie,’ and they form the section of the Branchifera. They are mostly inhabitants of the sea; but some of them inhabit fresh water. Shell of the Gasteropoda.—tvhe shell of the Gasteropoda is composed either of a single piece (univalve), or of a number of plates succeeding one another from before backwards (mul- tivalve). The univalve shell is to be regarded as essentially a cone, the apex of which is more or less oblique. In the simplest form of the shell the conical shape is retained with- out any alteration, as is seen in the common Limpet (Patella). In the great majority of cases, however, the cone is consider- ably elongated, so as to form a tube, which may retain this GASTEROPODA. 3 shape (as in Dentalium), but is usually coiled up into a spiral. The “spiral univalve” (fig. 384) may, in fact, be looked upon as the typical form of the shell in the Gastero- poda. In some cases the coils of the shell—termed techni- eally the “ whorls ””—are hardly in contact with one another (as in Vermetus). More commonly the whorls are in contact, and are so amalgamated that the inner side of each convolu- tion is formed by the pre-existing whorl. In some cases the whorls of the shell are coiled round a central axis in the same plane, when the shell is said to be “discoidal” (as in the common fresh-water shell Planorbis). In most cases, how- ever, the whorls are wound round an axis in an oblique manner, a true spiral being formed, and the shell becoming “turreted,” “trochoid,” “turbinated,” &c. This last form (fig. 383) is the one which may be looked upon as most char- acteristic of the Gasteropods, the shell being composed of a Fig. 383.—Cassis cancellata, a spiral Gasteropod. a, The ‘‘ spire,” placed at the posterior end of the shell; 0, The ‘‘mouth,” placed at the anterior end of the shell; c, Inner or colum- ellar lip; d, Outer lip; e, Notch for the passage of a respiratory siphon. number of whorls passing obliquely round a central axis or “columella,” having the embryonic shell or “nucleus” at its apex, and having the mouth or “aperture” of the shell placed at the extremity of the last and largest of the whorls, termed the “body-whorl.” The lines or grooves formed by the junc- tion of the whorls are termed the “ sutures,” and the whorls above the body-whorl constitute the “spire” of the shell. The axis of the shell (columella) round which the whorls are coiled is usually solid, when the shell is said to be “ imper- forate ;” but it is sometimes hollow, when the shell is said 4 GASTEROPODA. to be “perforated,” and the aperture of the axis near the mouth of the shell is called the “umbilicus.” The margin of the “aperture” of the shell is termed the “ peristome,” and is composed of an outer and inner lip (fig. 383), of which the former is often expanded or fringed with spines. When these expansions or fringes are periodically formed, the place of the mouth of the shell at different stages of its growth is marked by ridges or rows of spines, which cross the whorls, and are called “varices.” The animal withdraws into its shell by a retractor muscle, which passes into the foot, or is attached to the operculum; its scar or impression being placed, in the spiral Univalves, upon the columella. Fig. 384. — Scalaria Grenlandica, a Ho- Fig. 385.— Fusus tornatus, a Si- lostomatous Univalve. phonostomatous Univalve. Post- Post-Pliocene. Pliocene. In the multivalve Gasteropods the shell is composed of eight transverse imbricated plates, which succeed one another from before backwards, and are embedded in the leathery or fibrous border of the mantle, which may be plain, or may be beset with bristles, spines, or scales. In the marine Univalves two important variations exist in the form of the mouth of the shell. In one group (fig. 384) the mouth of the shell is unbroken or “ entire,” not having GASTEROPODA. 5 any notch or indentation of its margin. The shells in which the mouth has this form are termed “ holostomatous ;” and for the most part they belong to Gasteropods which are phytophagous, or live upon vegetable food. The possession, however, of a holostomatous shell in reality simply proves that the animal had no respiratory “siphons,” or tubes formed by the folding of the mantle. In a second group the aperture of the shell (fig. 385) is notched in front; and the shell is said to be “siphonostomatous.” There may be a posterior notch as well as the anterior one, and one or both of these notches may be produced into longer or shorter canals. The Siphonostomatous Univalves are mainly car- nivorous in their habits; but the notched mouth does not necessarily indicate the nature of the food. The possession of a siphonostomatous shell, on the contrary, merely in- dicates that the animal possessed tubular inflections of the mantle, or “respiratory siphons,” by which the water is con- veyed to and from the gills. Divisions of the Gasteropoda.—the following table shows the chief divisions of the Gasteropoda :— TABLE OF THE GASTEROPODA. Section A. BRANCHIFERA.—Respiration aquatic, by the walls of the mantle-cavity or by gills. OrpDER I, PRosoBRANCHIATA.—The branchie situated (proson) in advance of the heart. Division a. Siphonostomata.— Margin of the” shell - aperture notched or produced into a canal. This division comprises the families of the Strombide (Wing-shells), Muricide, Buccinide (Whelks), Conide (Cones), Volutide (Volutes), and Cypreide (Cowries). Division b. Holostomata.—Margin of the shell-aperture “ en- tire,” rarely notched or produced into a canal. This division includes the families of the Naticide, Pyramidellide, Cerithiade, Melaniade, Turritellide, Littorinide (Periwinkles), Paludinide (River-snails), Neritide, Turbinide (Top-shells), Haliotide, Fis- surellide (Keyhole-limpets), Calyptreide (Bonnet-limpets), Patel- lide (Limpets), Dentalide (Tooth-shells), and Chitonide. OrpDeER II. OpistHOBRANCHIATA.—Branchie placed towards the rear (opisthen) of the body. Division a. Tectibranchiata.—Branchie covered by the shell or mantle. A shell in most. Sexes united. The division includes 6 GASTEROPODA. the families of the Tornatellide, Bullide (Bubble-shells), Aply- siude (Sea-hares), Plewrobranchiade, and Phyllidiade. Division b. Nudibranchiata.— Animal destitute of a shell in the adult condition. Branchie external, on the back or sides of the body. This division includes the various naked Gasteropods commonly known as Sea-lemons and Sea-slugs. Orper III. NucLEoprANcHIATA, or HETEROPODA.—Shell present or absent. Animal free-swimming and oceanic, with a fin-like tail or flattened ventral fin. This order includes the two families of the Firolide and Atlantide. Section B. PutMontreRA.—Respiration aerial, by means of a pul- monary chamber. Orpver IV. InopercuLata.—Shell not provided with an oper- culum. This order comprises the families of the Helicide (Land- snails), Limacide (Slugs), Oncidiade, Limneide (Pond-snails), and Auriculide. Orper V. OpeRcULATA.—Shell provided with an operculum. In this order are the families Cyclostomide and Aciculide. Distribution of the Gasteropoda in time—As regards the general distribution of the Gasteropods in past time, all the families of the Prosobranchiata are known by fossil represen- tatives. Of the Opisthobranchiata the Tectibranchiate section is tolerably well represented in past time; but the section of the Nudibranchiata, from the total absence of the shell, is not known at all in the fossil condition. Both families of the Heteropoda are represented by fossil forms. The Pulmonate Gasteropods, from the fact that they either live on land or inhabit fresh water, are necessarily not so fully represented in past time as are the Branchiate Gasteropods. Still, nearly all the families of the air-breathing Univalves have fossil representatives. Taken as a whole, the Gasteropoda are represented in past time from the Upper Cambrian rocks upwards. Of the Branchifera, the Holostomata are more abundant in the Paleozoic period; and the Siphonostomata predominate more in the Secondary and Tertiary periods, attaining their maxi- mum at the present day. The place of the carnivorous Siphonostomata in the Paleozoic seas appears to have been filled by the Tetrabranchiate Cephalopods. The Branchiate Gasteropods of fresh water are chiefly represented as fossils by the genera Paludina, Valvata, and Ampullaria. GASTEROPODA. ie The Heteropoda are likewise of very ancient origin, having commenced their existence in the Upper Cambrian deposits. The genera Bellerophon, Cyrtolites, and Maclurea are ex- clusively Paleozoic; Bellerophina is found in’ the Gault (Secondary), and Carinaria has been detected in the Ter- tiaries. The Pulmonate Gasteropoda, as was to be anticipated, are not found abundantly as fossils, occurring chiefly in lacus- trine and estuarine deposits, in which the genera Lamnca, Physa, Ancylus, &e., are amongst those most commonly re- presented. These, however, are entirely Mesozoic and Kainozoic. In the Paleozoic period the sole known repre- sentatives of the Pulmonifera are the Pupa vetusta, Pupa vermilionensis, Dawsonella Meeki, and Zonites priscus of the Carboniferous rocks, In the following! are given the characters of those families of the Gasteropoda which occur in the fossil state, with the leading genera of each family and their range in time. SecTION A. BRANCHIFERA.—Respiration aquatic, generally by gills. ORDER I. PROSOBRANCHIATA.—Gulls situated im advance of the heart. Division a. Siphonostomata— Mouth of the shell notched, or produced into a canal. Fam. 1. Strompip#.—Shell with an expanded lip, deeply notched near the canal. Operculum claw-shaped. Foot narrow, adapted for leaping. All the existing genera of the Strombide are represented in the fossil state, but the family does not seem to have come into existence before the Jurassic period, and it attained its maximum in the Tertiary period. The genus Strombus has a shell with a short spire, a long aperture, and an expanded outer lip, there being a posterior as well as an anterior notch. The Strombs are represented in the Cretaceous and Tertiary rocks, but they attain their maximum in existing seas. The Scorpion-shells form the genus Pferoceras (fig. 386), in 1 In the characters of the families of the Gasteropoda, as in those of the Lamellibranchiata, Woodward’s ‘Manual of the Mollusca’ has been mainly followed. 8 GASTEROPODA. which the shell of the adult has its outer lip furnished with long claws, one of which forms a posterior canal close to the Fig. 386.—Pteroceras oceant. Neocomian. spire. Many fossil species are known, commencing in the Lias. In the genus Rostellaria (fig. 387), the spire is long, and has the posterior canal running up it. Many fossil species are known, commencing in the Cretaceous rocks. The outer lip is always expanded, and in some forms is enormously so. One of the most familiar species is the great A. ampla (fig. 387) of the London Clay (Eocene). Lastly, the genus Seraphs comprises smooth shells, with a short or obsolete spire, a thin outer lip, and a long narrow mouth. The fossil species date from the Eocene Tertiary. Fam. 2. Muricipa.—Shell with a straight anterior canal, the aperture entire posteriorly. Foot broad. The Muricide are essentially characteristic of the Tertiary and Recent periods. They commence, however, in the Jurassic rocks, in some doubtful examples, and they are certainly repre- sented in the Cretaceous rocks by not a few forms. In the genus JMurex the canal is often very long, and may be partially closed; the shell is ornamented with lon- GASTEROPODA. 9 gitudinal ridges or rows of spines (varices), and the aperture is rounded. Fig. 387.—Rostellaria ampla, reduced one-third. Eocene Tertiary. In the nearly-related Zyphis (fig. 388) there are tubular spines between the varices, and the last of these lodges the posterior siphon. Both Mu- rex and Typhis commence in the Eocene Tertiary, and have attaimed their maxi- mum in existing seas. 7'ro- phon, like the preceding, ranges from the Cretaceous to the present day; and Fulgur (fig. 391, D) is a Tertiary and Recent form. : 9 Fig. 388.—Typhis tubifer. Eocene Pisania commences to be 2 ea i represented in the Eocene, as do the genera Ranella, Triton, and Cancellaria. Fasciolaria and Pyrula (fig. 391, £) commence their existence in the Cre- taceous rocks; and Zurbinella and Trichotropis do not make their appearance till the Miocene. Lastly, the great genus 10 GASTEROPODA. Fusus, distinguished by the spindle-shaped, many-whorled shell, and long straight canal (fig. 389), appears to have its commencement in the Oolites. Species of Fusus become very numerous towards the close of the Cretaceous period, and they are very plentiful in the Tertiaries. One of the common fos- Fig. 389.—Fusus Neocomiensis. Fig. 390.—Buccinwm undatum (var.) Lower Greensand. Post-Pliocene and Recent. sils of the Red Crag (Newer Pliocene) is the reversed shell, Fusus contrarius (fig. 391, F), which is now known to exist in the living state as well. The most ancient representative of the Muricide, if rightly referred here, is probably the genus usispira (fig. 391, A), of the Lower and Upper Silurian. In this genus the shell is fusiform, with an elevated spire, the mouth being elliptical and produced below, and the columella twisted, but without folds. Fam. 3, Bucctnip#.—Shell notched anteriorly, or with the canal reflected, producing a kind of varix on the front of the shell. With the exception of the extinct genus Pur- purina of the Lower Oolites, and some species of Buccinwim in the Cretaceous rocks, the family of the Buccinide is ex- clusively confined to the Tertiary and Recent periods. The two great families, therefore, of the Muricide and Buccinide: are essentially characteristic of the later periods of the GASTEROPODA. let earth’s history. The most important fossil genera of the Buccinide are Buccinum, Terebra, Nassa, Purpura, Cassis, and Oliva. The Whelks form the genus Buccinum (fig. 390), distin- guished by the ventricose body-whorl, large aperture, and short reflected canal. Some few species of Buccinuwm are found in the Cretaceous rocks; but the genus is essentially Tertiary and Recent. Terebra comprises the Auger-shells, distinguished from the Whelks by their long, pointed shells, consisting of many Fig. 391.—a, Fusispira terebriformis—Lower Silurian (after Hall); 8, Nassa pusillina— Pliocene (after Searles Wood) ; c, Ringicula ventricosa—Pliocene (after Searles Wood); p, Ful- gur canaliculatus—Miocene ; E, Pyrula réticulata—Pliocene ; F, Fusus contrarius—Pliocene ; G, Purpura tetragona—Pliocene (after Searles Wood); H, Subulites terebriformis—Upper Silu- rian (after Hall). whorls, and having a small mouth. They commence in the Eocene Tertiary. The Dog-whelks (Massa) also commence in the Eocene, and are distinguished from the Whelks chiefly by having the columellar lip expanded and callous, with a tooth near the anterior canal (fig. 391, B). The shells of the genus Purpura (fig. 391, G) have a short spire and wide 12 GASTEROPODA, aperture, with an expanded and flattened inner lip. They commence in the Miocene Tertiary. Ringicula (fig. 391, c) has a ventricose shell, with a small spire, the columella callous and deeply plaited, and the outer lip thickened and reflected. The genus commences in the Miocene Tertiary, and is represented by living species. We may also, perhaps, place in this family, possibly in the neighbourhood of Zerebra, the Silurian genus Subulites (891, H), which in this case is the most ancient representative of the family Buccinide. The shell in this genus is very long and slender, with a long spire, and an extended body-whorl. The mouth is narrow, with a sharp, not callous lip; the columella is truncated below, not plaited or toothed; and there is a deep basal notch. The Helmet-shells (Cassis) begin in the Eocene, and are distinguished by their short spire, large body-whorl, long aperture, recurved canal, and expanded inner lip. Lastly, the Olives (Oliva, fig. 392, a) and Rice-shells (Olivella) are char- acterised by their cylindrical polished shell, with a short spire, a long narrow aperture, notched in front, and an obliquely- striated columella. The living Olives are tropical and sub- tropical in their distribution, and the fossil species, except for two or three Cretaceous species of Olivella, commence in the Eocene Tertiary. Ancillaria (fig. 392, B), dating from the Eocene, is nearly related to Oliva, but the spire is pro- duced, and wholly covered with enamel. Fam. 4. Contp#—Shell inversely conical, with a lone narrow aperture, the outer lip notched at or near the suture. The Conide commence in the Cretaceous rocks, abound in the Tertiaries, and attain their maximum at the present day. The true Cones form the genus Conus (fig. 392, ©), and are distinguished by their short spire and regularly conical shell, of which the outer lip is notched near the suture. The Cones are represented in the Chalk, but are mainly Tertiary and Recent. Gosavia comprises Cones with a plaited columellar lip, and is essentially a Cretaceous type. The genus Plewrotoma (fig. 392, D) is distinguished by a spindle-shaped shell, with a long spire, the outer lip having a deep slit near the suture. The genus commences in the Chalk, and has an enormous development in the Tertiaries, GASTEROPODA. Ike} from which nearly three hundred species are known. The maximum, however, is attained in existing seas, in which Fig. 392.—a, Oliva Branderi—Eocene ; B, Ancillaria glandina—Hocene ; c, Conus deperditus —Eocene ; D, Plewrotoma rostrata—Hocene. there are very numerous species. Borsonia, dating from the Eocene, is near the preceding, but has an obliquely-folded columella. Fam. 5. VoLutip®.— Shell turreted or convolute, the aperture notched in front; the columella obliquely plaited. No operculum. Foot very large; mantle often reflected over the shell. The living members of the Volutide are chiefly inhabitants of warm seas, and are often remarkable for their brilliant colours. The family does not appear to have existed till towards the later portion of the Cretaceous period; but it is abundantly represented in the Tertiaries, and attains its maximum in existing seas. The most im- portant genera are Voluta and Mitra. The true Volutes form the genus Voluta (fig. 393), charac- terised by the short spire, large, deeply-notched aperture, and columella with several plaits. Species of Voluta occur in the Cretaceous period, but the genus is mainly Tertiary and 14 GASTEROPODA. Recent. There are several sub-genera of Voluta, the most important being the Eocene Volutilithes, with its many- whorled spire. In the genus Mitra the shell is spindle-shaped, with a long spire and small mouth. The Mitre commence in the Cretaceous period, but the fossil species are mainly distributed through the Tertiary formations. Col- umbellina and Lyria are Cretaceous ; and the living genera Volvaria and Marginella begin in the Eocene. Fam. 6, Cypra&ip&.— Shell convol- ute, enamelled; spire concealed ; aper- ture narrow, channelled at each end. Outer lip thin in the young shell, but thickened and inflected in the adult. Foot broad; mantle forming lobes which meet over the back of the shell. The only important genus of this family is that of Cyprea (fig. 394), comprising the numerous and well-known living shells which are commonly called Cow- ries. The Cypreww are mainly, but not exclusively, inhabitants of warm seas, Fig. 393.—Voluta elongata. Chalk. and they attain their highest develop- ment between the tropics. The fossil species date from the Cretaceous period, and abound in the Tertiaries. The shell of the Cowries in the young state is furnished with a prominent spire, and has a thin outer lip. In the adult state (fig. 394) the spire is completely concealed within the shell, the entire surface is generally covered with shining enamel, the inner lip is crenulated, and the outer lip is thick- ened, inflected, and crenulated. The small Cowries of which Cyprea Europea is the type, are not known as occurring in the fossil condition. Ovuluwm, dating from the Eocene, re- sembles Cyprea, but the inner lip is smooth. Division b. Holostomata.— Margin of the shell - aperture “entire,” rarely notched or produced into a canal. GASTEROPODA. Le Fam. 7. Naticip#.—Shell globular, of few whorls, with a small spire; outer lip acute; inner lip (pillar) often callous. Foot very large; mantle -lobes hiding more or less of the shell. This family is stated to commence in the Upper Si- lurian rocks; but there is considerable uncertainty as to the true affinities of the Paleozoic fossils which are referred here. The most important fossil genus is Natica itself. The shell in Natica (fig. 8395) is thick, smooth, and polished, often with coloured markings. The inner lip is callous, and _ F og : 5 Fig. 394.—Cyprea elegans. the shell is umbilicated. Fossil Naticw Eocene Tertiary. have been described from the Upper Silu- rian, Devonian, Carboniferous, and Permian rocks ; and they are very abundant in all the Secondary and Tertiary for- mations. There is great doubt about the true affinities of the more ancient shells referred here ; and the typical Naticw, with a wide umbilicus and a twisted columella, are represented by very few forms even in the Cretaceous period. Naticopsis (fig. 397, B) of the Carboniferous; Naticella of the Trias; the Jurassic Huspira, with its elevated spire and angulated whorls ; and the Tertiary Globulus, are close allies Htaeanie agus of Natica proper. Narica (fig. 397, c), Post-Pliocene. with its spirally-striated shell, and Am- aura, range from the Cretaceous to the present day. Desha- yesia, of the Eocene, is a lnk between the Naticide and Neritide ; and Sigaretus (fig. 397, 4), ranging from the Eocene to the Recent period, is easily recognised by its wide aperture and minute spire. Fam. 8. PYRAMIDELLIDA.—Shell turreted, with a small aperture ; sometimes with one or more prominent plaits on the columella. Operculum horny and imbricated. The Pyramidellide commence in the Lower Silurian rocks, and appear to be on the decline at the present day. The chief 16 GASTEROPODA. fossil forms belong to the genera Pyramidella, Chemnitza, Eulima, Loxonema, and Macrocheilus. In Pyramidella (fig. 397, D) the shell is slender and tur- reted, and the columellar lip is plaited. The genus is doubt- fully represented in the Cretaceous, but there are various Ter- tiary and many living species. Odostomia, with a few Cretaceous representatives, but occurring more abundantly in the Tertiary, includes minute turreted shells with a single tooth-like columellar fold. Chemnitzia (fig. 397, G) includes a num- ber of slender, turreted, many-whorled shells, with plaited whorls, and a simple aperture. The genus appears to com- mence in the Permian rocks, and whilst more than one hundred and fifty fossil species are known, the number of the living forms is very small. Many of the ae ae ees shells, however, included under this head, are of very doubtful affinities. Eulima (fig. 397, F) ineludes small, polished, elongated shells, with level whorls and a reflected inner lip. Hulume are of doubtful occurrence in the Carboniferous rocks, are sparingly represented in the Secondary rocks, and are toler- ably abundant in the Tertiaries. Loxonema (fig. 397, E) extends from the Silurian to the Trias, but is most abundant in the Carboniferous. The shell in this genus is long and turreted, with convex whorls, which have no spiral band, while the surface is covered with longitudinal, often more or less arched threads or ridges. Macrocheilus (fig. 396) includes thick smooth shells, with convex whorls, an oval, not distinctly notched aperture, a callous inner lip, and an imperforate columella. The genus is mainly or exclusively Devonian and Carboniferous, and no Secondary or Tertiary forms have been detected, though a living Japanese shell has been referred here. The Carbon- iferous Orthonema is allied to Loxonema, and the Soleniseus of the same formation probably also belongs to this family, though it has affinities with Fuasciolaria. GASTEROPODA. 17 _ Fam. 9. CErRITHIAD&. — Shell spiral, turreted; aperture channelled in front, with a less distinct posterior canal. Lip generally expanded in the adult. Operculum horny and spiral. The Cerithiade are exclusively confined to the Fig. 397.—a, Sigaretus clathratus—Eocene; 8B, Naticopsis plicistria—Carboniferous (after M‘Coy); c, Narica Genevensis—Cretaceous (after Pictet); p, Pyramidella leviuscula—Pliocene (after Searles Wood); ©, Loronema rugifera—Carboniferous (after Phillips); r, Hulima vagans— Jurassic (after Morris and Lycett); G, Chemnitzia internodula—Eocene (after Searles Wood). Secondary, Tertiary, and Recent periods, and are represented in the Tertiary rocks by a vast number of forms. The most important fossil forms belong to the genera Cerithiwm, Potamides, Nerinwa, and Aporrhais, of which Nerinwa is extinct, and is exclusively confined to the Secondary period. For all practical purposes Cerithium and Potamides may be considered together, as no strict line of demarcation can be drawn between the fossil forms. In both, the shell is turreted and many - whorled (fig. 398), with or without varices. The aperture of the shell is small, with a tortuous an- terior canal, and an expanded outer lip. Most of. the living forms are inhabitants of fresh or brackish waters, and they are chiefly found in hot climates. The fossil forms, to the number of nearly five hundred, commence in the Trias, but they attain their maximum of development in the Eocene Tertiary. MOL soLT. B 18 GASTEROPODA. In the genus Nerinwa (figs. 399 and 400) the shell is turreted, many-whorled, and nearly cylindrical. The colum- ella carries continuous ridges, and similar ridges exist on the Fig. 400.—Nerinea Goodhallit, one-fourth of the natural size. The Fig. 398.—Cerithium Fig. 399.—Nerincea left-hand figure shows the appear- heaagonum. Eocene bisulcata. Chalk. ance presented by the shell when Tertiary. vertically divided. Coral Rag, England. interior of the whorls, so that casts of the interior of the shell are often very unlike the form of the exterior. The aperture of the shell is channelled in front. The species of Nerinea are exclusively Jurassic and Creta- ceous, and are very numerous. One of the limestones of the Jura, be- lieved to be of the age of the Coral Rag (Middle Oolite) of Britain, abounds to such an extent in these shells as to have gained the name of “ Calcaire & Nérinées.” With the preceding may be as- sociated the Secondary genera Hu- stoma, Exelissa, Fibula, Cryptoplocus, and Certtella, and the Tertiary, Quoyia and Mesostoma. Hig. 401. = Aporrhais Parkin: The genus Aporrhais, with various Tae ees (After J. pelated forms, constitutes a distinct croup, with strong alliances with the Strombide, and often raised to the rank of a distinct family (Aporrhaidw). The shell in Aporrhais (fig. 401) is GASTEROPODA. 19) spindle-shaped, with a turreted spire, the outer lip of the adult being greatly expanded and lobed. Owing to the development of a well-marked anterior canal, and often of an equally conspicuous posterior tube as well, the shell be- comes distinctly “siphonostomatous,” and the genus should probably be placed in the immediate vicinity of Pteroceras and Rostellaria. The entire group makes its first appearance in the Jurassic period, attained its maximum in the Creta- ceous, decreased in number in the Tertiary, and is repre- sented by a few forms at the present day. Fam. 10. MeLantap#.—Shell spiral, turreted; aperture often channelled or notched in front; outer lip acute. Operculum horny and spiral. Many fossil shells have been referred to the Melaniade, but it is probable that most of these belong to the Paleozoic genus Lozonema and the Mesozoic Chemmitzia. Various forms of JJelania have been described from the later Secondary rocks, and the genus is well represented in the Tertiary period, as are also the allied Melanopsis and Gyrotoma. All the living species in- habit fresh water, generally in the warmer parts of the world; and it is probable that all the fossil species occur only in fluviatile and lacustrine deposits. Fam. 11. TurriveLtip#—Shell tubular or spiral, often turreted; upper part partitioned off; aperture simple. Oper- culum horny, many-whorled. Foot very short. Branchial plume single. The TZwrritellide are not known to have existed in the Paleozoic period; but they appear to com- mence about the middle of the Jurassic period, abounding in the Tertiaries, and attaining their maximum in existing seas. The chief fossil genera are Turritella, Vermetus, and Scalaria. In Turritella (fig. 402) the shell is turreted, many- whorled, and spirally striated; the aperture is small and rounded, and the peristome thin. Species of Twrritella have been described from the Paleozoic and older Mesozoic formations, but almost certainly belong to the genera Muwr- chisonia aid Loxonema. The genus is for the first time represented with certainty in the Lower Cretaceous rocks (Neocomian), and many fossil species are found in the Tertiaries. 20 GASTEROPODA. The genus Vermetus comprises tubular shells, the chief interest of which is the strong resemblance which they show Fig. 402.—Turvritella angu- Fig. 403. — Siliquaria Fig. 404. — Scalaria lata. Neocomian. anguina. Pliocene and Grenlandica. Post- Recent. Pliocene and Recent. to the Annelidous genus Serpula. The shell is attached, and though regularly spiral when young, is always irregular in its growth when adult. The fossil species are best distin- euished from Serpula by the fact that the tube is repeatedly partitioned off by calcareous septa as the animal grows. It is, however, often a matter of extreme difficulty to deter- mine whether a given specimen be a Verimetus or a Serpula. Fossil Vermeti are known from the Lower Cretaceous up- wards. Siliquaria (fig. 405), dating from the Eocene Ter- tiary, resembles Vermetus in most respects, but the tube has a continuous longitudinal sht. These two forms are often regarded as a separate family (Vermetide). In Caecum, again, also often looked upon as forming with some allied types a distinct family (Cacide), the shell is at first discoidal, but becoming decollated with age, has the form of a curved cylindrical tube when adult. The genus commences in the Eocene Tertiary. The genus Scalaria, comprising the Wentletraps, is the type of another group now commonly looked upon as a dis- tinct family (Scalide or Scalaride), the characteristics of the section being the possession of a spiral and turreted shell, usually marked with longitudinal ribs, and having the aper- ture round and with an entire margin. In Scalaria (fig. GASTEROPODA. Zall 404) itself the shell is very like that of Turritella, but the whorls are ornamented with transverse ribs, and the peris- tome is continuous round the circular aperture. The Sca/- arie commence in the Middle Oolites (Coral Rag), and attain their maximum in existing seas. Cochlearia, of the Trias, differs from the preceding chiefly in its expanded peristome. We may also place here, provisionally at any rate, the genus AHolopella, which resembles Sealaria in general form and in the characters of the peristome, but in which the longitudinal ribs are reduced to mere striz. The genus is principally Paleeozoic, commencing in the Silurian ; but it is said to occur in the Trias. The Paleozoic Holopea seems to have the entire aperture of the Scalidw, but there are other features in which it resembles both the Naticide and Littorinidew, and it will be here temporarily placed in the latter family. Fam. 12. Lirrormsipa.—Shell spiral, top-shaped, or de- pressed ; aperture rounded and entire, operculum horny and pauci-spiral. The exact range of the Littorinide in time is uncertain, owing to the difficulty of determining the true affinities of many fossil univalves. Several Paleeozoic and Mesozoic shells have been referred to JLittorina, and the genus Rissow commences in the Permian. The family, however, is mainly characteristic of the Tertiary and Recent periods. We may, nevertheless, consider here a number of more or less important Paleozoic genera, some of which seem undoubtedly to belong to the Littorinidw, while others very probably do so, or, at any rate, do not possess decisive points of relationship with other families. The Littorinide may be divided into three groups, sometimes regarded as distinct families, and typified by the genera Littorina, Sola- rium, and Rissoa. In the genus Zittorina are the true Periwinkles, distin- guished by their thick, generally. top-shaped and pointed shells, of few whorls, and with an imperforate columella. The undoubted fossil species range from the Cretaceous to the present day. We may also provisionally place near JLittorina the Paleozoic genera Holopea and Platyostoma. The former is 22 GASTEROPODA. Silurian and Devonian, and includes thin, conical, often smooth shells, with an expanded body-whorl (fig. 405). The mouth of the shell is entire, and the peristome seems to be sometimes complete, as in the Scalaride. The Devonian Lsonema has angular whorls and a rhombic mouth, but in other respects resembles Holopea. In the Silurian and Devonian Platyostoma, again, the body-whorl is immensely ex- Fig. 405.— Holopew panded. Lastly, the genus Cyclonema, Guelphensis, (Billings.) #0 0 Middle Silurian. ranging from the base of the Silurian to the top of the Devonian, has a conical shell, which is characterised by the possession of fine spiral striz, often with transverse strize as well. In the genus Solarium, comprising the “ Staircase Shells,” the shell (fig. 406) is much depressed; there is a large and deep umbilicus, running from the base to the apex of the shell; and the aperture is rhombic. The edge of the umbilicus is, typically, crenu- lated; and the shell is not pearly within. The genus appears in the Secondary period, is represented by undoubted species in the Cretaceous, is not uncommon in the Tertiaries, and survives at the present day. Lifrontia, Kocene and Recent, has the body-whorl free. Phorus (fig. Supe ee te 7) comprises trochoid shells, with Gault (Upper Cretaceous). a concave base and flattened whorls. Very usually foreign bodies, such as shells or small pieces of stone, are attached to the surface and margins of the shell. There is considerable uncertainty as to the geological range of the genus, species having been described from deposits as old as the Devonian; but the first undoubted forms occur in the Jurassic, and there are various Tertiary and living types. We may also place here the genus Cirrus (fig. 408), in which the shell is discoidal co) and there is a large umbilicus; while the upper surface GASTEROPODA. 23 bears a row of spines, which in the neighbourhood of the aperture are tubular and have their ends perforated. The genus ranges from the Devonian to the Jurassic. Fig. 407.—Phorus canaliculatus. Cretaceous. Tn accordance with the views now most generally accepted, we must also place here the important and widely-distributed Paleeozoic genus Huomphalus, with its alles. Fig. 408.—Cirrus Goldfussit. Devonian, The genus Luomphalus (figs. 409, 410) is entirely extinct, and is essentially Paleozoic, ranging from the Silurian to the Fig. 409.—Euomphalus De-Cewi (Billings). a, Front view ; b, View of the umbilicus. Devonian. Trias, but being most abundant in the Carboniferous rocks. The shell in this genus is depressed or discoidal, the whorls DA GASTEROPODA. lying nearly or quite in the same plane. The whorls are angulated or coronated, the aperture is polygonal, the um- bilicus is very large, and there is a shelly operculum. The genus Straparolus (or Straparollus) is closely related to Huomphalus, and, strictly speaking, is probably identical with it. It is convenient, however, to retain both names, employing that of Zwomphalus for the forms with a depressed discoidal shell, with angular whorls and an open umbilicus Fie 10-—Rromphalas dios Urret (ig 410); while the title Straparolus may be applied to those with rounded non-angulated whorls, a small um- bilicus, and a more or less prominent spire. Huomphalop- terus, of the Upper Silurian, includes forms allied to Huomphalus, but having winged whorls, the alation being perforated by canals which open internally into the cavity of the shell, and externally by minute pores on the margin of the wing. Straparollina, again, includes Paleozoic shells, believed to stand midway between Straparolus and Holopea. The shells which have been described under the names of Raphistoma, Ophileta, and Helicotoma—prin- cipally or exclusively Lower Silurian in their range—are apparently closely allied to Huomphalus, if, indeed, they are really separable from it. Lastly, some paleontologists would place here the singular genus MJaclurea, which, however, is perhaps best regarded as one of the Heteropods; and we shall also temporarily consider Ophileta as belonging to the same group. Finally, we have a group of Littorinide typified by the genus Lissow (fig. 411), in which the shell is small, pointed, and many-whorled, with a small round aperture surrounded by a continuous peristome. Many fossil species are known, commencing in the Permian; and the genus is universally distributed at the present day. Among the allies of Rissoa, Lissoina appears first in the Jurassic, Keilostoma is found in the Cretaceous and Eocene beds, and Diastoma and Pterostoma are Eocene types. GASTEROPODA. 25 Fam. 13. Patupin1ip&.—Shell conical or globular; aper- ture rounded and entire; operculum horny or shelly. The Paludinide are essentially inhabitants of fresh water; though they sometimes live in brackish, or even in salt water. As a matter of course, therefore, they are chiefly, if not exclusively, found as fossils in deposits which are believed to be fluviatile or lacustrine in their origin. ‘The three chief living genera are, Paludina (fig. 411, 8B), Valvata (fig. 411, c), and Ampul- 5 Fig. 411.—a, Rissou supracostata—Pliocene, enlarged six times ; B, Paludina lenta—Plio- cene; ¢, Valvata piscinalis, viewed from in front and from below—Pliocene. (After Searles Wood.) laria. The two former date from the Cretaceous period, the first possibly from the Jurassic, and both abound in the Wealden and in many Tertiary deposits. Lithynia resembles Paludina, but the operculum is shelly. Valvata may be top-shaped or discoidal, but the shell is umbilicated, and the peristome is entire. The existence of Ampullarie in a fossil state is attended with considerable uncertainty, chiefly from the great difficulty, or impossibility, of separating them from species of the marine genus Natica. Fam. 14. Neririp#.—Shell thick, globular, with a very small spire; aperture semi-lunate, its columellar side ex- panded ; outer lip acute. Operculum shelly, sub-spiral. The Neritide are not known as occurring in the Paleozoic rocks, but are found from the Jurassic period onwards, attaining their maximum at the present day. In the genus Werita (fig. 412) the shell is thick, with a broad columella, the inner edge of which is straight and toothed. The outer lip is thickened and often denticulated internally. The true Nerites are inhabitants of warm seas ; 26 GASTEROPODA. and they date in past time from the Lias. The nearly-allied genus Neritina includes the so-called “ fresh-water Nerites,” which agree in most characters with Merita, but inhabit fresh or brackish waters, and have a comparatively thin smooth Fig. 412.—Nerita Schemidelliana. Eocene Tertiary. shell. The fossil species commence in the Eocene Tertiary. The Jurassic genus Neritoma has a thick ventricose shell, with a notch in the middle of the outer lip. eritopsis, again, commences in the early portion of the Secondary period, and still survives. Its shell is distinguished by the possession of a single notch in the middle of the inner lip. In connection with this genus we must mention the curious Jurassic fossils which have been described under the name of Peltarion. These are oval or nearly circular calcareous plates, concave above and flattened below; and they have generally been regarded as the mandibles of Tetrabranchiate Cephalopods. Recent researches, however, seem to show that these singular bodies are really the opercula of species of Neritopsis. Lastly, the genus Pileolus comprises small limpet-shaped shells, with a semi-lunar aperture below. The only known fossil species are from the Lower Oolites (Great Oolite). Fam. 15. Turpintipa&.—Shell turbinated (top-shaped) or pyramidal, nacreous (ie. pearly) inside. Operculum horny and multi-spiral, or calcareous and pauci-spiral. The family of the Turbinide has a high antiquity, the forms ascribed to it dating from the Lower Silurian; but many of the older shells referred to this family are of more or less doubtful affinities. In the genus Turbo (fig. 413) the shell is turbinated, with GASTEROPODA. Di a round base. The whorls are convex; the aperture is large and rounded; and the operculum is calcareous. . SSS Fig. 499.—a, Lepidosteus osseus, the ‘‘Gar-pike” of the American lakes; B, Aspidorhyn- chus, restored (after Agassiz), a Jurassic Ganoid allied to Lepidosteus, but having a homo- cereal tail. others (Acipenser and Scapirhynchus) have detached dermal plates of true bone. 3. As to the jins, both pectorals and ventrals are usually present, and the ventrals are always placed far back, in the neighbourhood of the anus, and are never situated in the im- mediate vicinity of the pectorals. In some living and many Fig. 500.—Ganoid Fishes. a, Polypterus (recent); B, Osteolepis (extinct). a, One of the pectoral fins, showing the fin-rays arranged round a central lobe; 6, One of the ventral fins; c, Anal fin; d, Dorsal fin ; d’, Second dorsal fin. extinct forms the fin-rays of the paired fins are arranged so as to form a fringe round a central lobe (fig. 500). This ORDERS OF FISHES. 133 structure characterises a division of Ganoids called by Hux- ley, for this reason, Crossopterygide, or “ fringe-finned.” The form of the caudal fin varies, the Ganoids being in this re- spect intermediate between the Bony fishes, in which the tail is “homocercal,’ and the Sharks and Rays, in which there is a “heterocercal” caudal fin. In the majority of Ganoids, then, the tail is unsymmetrical or “ heterocercal,” but it is sometimes equi-lobed or “ homocereal.” The living genera of Ganoids are exclusively or mainly inhabitants of fresh waters; but many of the extinct forms occur in association with marine animals, and must therefore be assumed to have inhabited the sea. Others, again, are found in undoubted lacustrine deposits ; and lastly, there are others which are found in beds where there are no other fossils which can be certainly asserted to have lived either in fresh or salt water; and as to the mode of life of these we must at present remain in doubt. As regards their general distribution im time, the oldest representatives of the fishes belong, so far as is yet known with certainty, to this order. The order, namely, is repre- sented in the Upper Silurian rocks of Bohemia and Britain by several Ganoid fishes, which have been referred to five distinct genera. In the Devonian rocks, or Old Red Sand- stone, the Ganoids attain their maximum. ‘The singular family of the Cephalaspidw appears to die out finally at the close of this period, and the great group of the Cvosso- pterygide attained here its highest development, being repre- sented at the present day by the single genus Polypterus. The Carboniferous and Permian rocks contain an abundance of Lepidoganoids. In the Mesozoic period, the Lepidoganoids are very largely represented by various extinct types, many of which belong to the family of the ZLepidosteidw—repre- sented at the present day by the Bony Pike or Gar-pike of North America. Here, also, we have for the first time rep- resentatives of the family of the Chondrosteide, to which the living Sturgeons belong. Lastly, in the Oolitic rocks appear for the first time Lepidoganoids with homocercal tails, and they continue to be represented up to the present day. In the Tertiary rocks true Sturgeons (Acipenser) make their 134 ORDERS OF FISHES. appearance; but the Ganoids are now considerably out- numbered by the Teleostean fishes; and the latter have a still more marked predominance at the present day. The classification of the Ganoid fishes has hitherto proved a matter of considerable difficulty ; and probably no arrange- ment that has been as yet proposed can be regarded as being, in all its details, more than provisional. A conveni- ent primary division is that into Lepidoganoids, in which the body is furnished with scales of moderate size, and the endoskeleton is generally more or less perfectly ossified ; and Placoganoids, in which the skeleton is imperfectly ossified, and the head and more or less of the body are protected by large ganoid plates, which in many cases are united together by sutures. Accepting this division, the order Ganoidei may be divided into the following sub-orders :— SEcTION 1.—LEPIDOGANOIDEI. Sub-order A. Amiade. Lepidosteidee. Platysomide. Crossopterygide. Acanthodide. HOw SECTION 2.—PLACOGANOIDEI. Sub-order F. Ostracostet. 95 G. Chondrosteide. The position of at least two of these sub-orders (viz, Acanthodide and Ostracoste’) in the order of the Ganoids is questionable. In any case, the number of forms included in these sub-orders is so large that nothing more can be done here than simply to draw attention to some of the more striking examples of each. Sup-orper A, AmiAD&—In this sub-order are included Ganoids in which the scales are rounded and overlap one another, and the tail is slightly heterocercal. The vertebral column is ossified, and the external appearance approaches closely to that of an ordinary Teleostean fish. A pree-oper- culum is present, with branchiostegal rays, a median jugular plate, and non-lobate paired fins. This division is repre- ORDERS OF FISHES. 1 e35) sented at the present day by the Trout-like “ Dog-fishes ” (Amia) of the North American lakes; and forms only specifically separable from the recent ones occur in the Tertiary formations of the same country. No pre-Tertiary examples of the group are as yet known; though it is by no means impossible that some Mesozoic forms may ulti- mately prove to be Amioids. SUB-ORDER B. LEPIDOSTEIDA.— Seales rhomboidal, not overlapping ; tail heterocercal, sometimes homocercal ; paired fins not lobate; fin-borders generally with fulcral scales ; branchiostegal rays not modified to form “jugular plates.” This sub-order is represented at the present day by the Gar-pike (Lepidosteus, fig. 499, A) of the North American continent, and it attained its greatest development in the Mesozoic period. The exact range of the sub-order in time is uncertain, as it has not yet been determined what forms should be included in it. The oldest known type is the Cheirolepis of the Devonian, which has been shown by Dr Traquair to be allied to Palwoniscus. In the Carboniferous and Permian rocks the sub-order is mainly represented by the genera Palwoniscus and Amblypterus (fig. 501), im which WSS > Fig. 501.—Rhabdolepis (Amblypterus) macropterus. Lower Permian. (After Agassiz.) the tail is heterocercal, and the jaws are furnished with numerous minute teeth. Numerous species of these genera are known in the above-mentioned formations, and both appear for the last time in the Trias. Belonging to the same family as the preceding (Palwoniscidw) are various genera from the Upper Paleozoic rocks, such as Pygopterus, 136 ORDERS OF FISHES. Nematoptychius, Gonatodus, Cycloptychius, &c.1 In the Secon- dary rocks Zepidosteids are extremely abundant, the chief forms belonging to the families Dapedidw, Lepidotide, and Leptolepide. In the Dapedide (fig. 502, 1), the tail-fin is only slightly heterocercal, the scales are interlocked by pegs and sockets, and the back teeth are obtuse. Dapedius Fig. 502.—1, Dapedius tetragonolepis ; 2, Leptolepis sprattiformis; 3, Lepidotus Valdensis. S ? f g PS 5 Hy op Lv ys > L itself is compressed and deep - bodied, and is exclusively confined to the Lias. The front teeth in this genus are typically notched or bifureate. The Jurassic chmodus (fig. 503) has been separated from Dapedivs upon the ground that the teeth have unicuspidate crowns; but this alleged distinction has been shown to be neither constant nor reliable, and the former name must therefore be abandoned. The Jurassic genus Tetragonolepis is closely allied to Dapedius, especially in its greatly compressed body and its single long dorsal fin; but, as shown by Quenstedt 1 Contrary to the views which have usually been held by ichthyologists, Dr Traquair has expressed the opinion that the Paleoniscidw (as also the Platysomide) are more nearly allied to the Acipenseroids than to the Lepi- dosteide. ORDERS OF FISHES. 137 and Sir Philip Egerton, the articulation of the scales, instead of being by pegs and sockets, as in Dapedius, rather re- sembles that of the “Pycnodonts,” to which the genus is very closely allied. Each scale, namely, bears upon its inner anterior margin a thick, solid, bony rib, extending Fig. 503.—Dapedius (chmodus), restored. Lias. upwards beyond the margin of the scale, and sliced off obliquely above and below, on opposite sides, for forming splices with the corresponding processes of adjoining scales. The Lepidotide have a homocercal tail (fig. 502, 3), and possess obtuse teeth. The type-genus, Lepidotus, ranges from the Lias to the Eocene Tertiary. The Leptolepide (fig. 502, 2) have also a homocercal tail, and possess small rounded scales. The species of this family are all Secondary in their distribution. According to the researches of Traquair, the well-known group of Secondary fishes comprised under the name of Pycnodontide, should really be placed under the Lepidosteids, rather than with the Platysomide, as has usually been done. In this group the body is rhomboidal and compressed, and covered with rhombic scales, while the teeth are characteris- tically blunt and rounded. In the true Pycnodonts the teeth (fig. 504) are multiserial, and are adapted for crushing; consisting of “a circular or transversely oval crown, flattened above, and sessile on the bone to which it is attached; or of an obtusely conical crown, which is broader than its peduncle of support” (Young). There are typically five rows of teeth on the vomer, while the lower jaw carries a corresponding series of three, four, or five rows of dental 138 ORDERS OF FISHES. plates. The Pycnodonts (Pycnodus, Gyrodus, Celodus, Meso- don, &c.) are principally Jurassic; but there are various Cretaceous forms, and a few Eocene and Miocene types are Fig. 504.—Under surface of the vomer of Celodus gyrodoides, showing the rows of crushing teeth. Cretaceous. (After Sir Philip Egerton.) known. The Triassic Placodus, formerly referred to this family, is now known to be truly Reptilian. SuB-oRDER C. PLatysomip&.!— The fishes included in this division are mainly Carboniferous and Permian, and have a close general resemblance to the Pyenodonts. The body is deep and compressed; and the scales are rhom- 1 The separation of the Pyenodonts and Platysomide, and the elevation of the latter to the rank of a distinct division of Ganoids are in accordance with the views of Dr Traquair, our greatest authority upon the subject of the fossil fishes. In this connection the author has to return his best thanks to Dr Traquair for the permission to make use of his researches on this subject, which will shortly appear in the ‘Transactions of the Royal Society of Edin- burgh,’ but which are as yet unpublished. The author has also to gratefully acknowledge much other friendly assistance as regards the fossil fishes from the same source. ORDERS OF FISHES. 139 boidal, and are articulated to one another by processes developed on the internal surface of their anterior margins. In the genus Platysomus (fig. 505) the tail is heterocercal, the dorsal and anal fins are long, the pectorals are small, and the ventrals appear to be wanting. The teeth are conical and uniserial, and the body is deep and compressed Fig. 505.—Platysomus gibbosus. Middle Permian. from side to side. The Platysomi are mainly found in the Permian rocks. Another genus of this family is the Car- boniferous Cheirodus of M‘Coy (= Amphicentrum), in which the body is deep and rhombic; the scales are high and narrow; and the front of the jaws is edentulous, while the palate and hinder portion of the mandible are furnished with ridges carrying “small tubercular tooth -like eleva- tions” (Traquair). The other genera included by Traquair in the family of the Platysomide are Eurynotus, Benedenius, Mesolepis, Hurynomus, and Wardichthys. SUB-ORDER D. CROSSOPTERYGIDA.—“ Dorsal fins two, or, if single, multifid or very long; the pectoral, and usually the ventral, fins lobate; no branchiostegal rays, but two principal, with sometimes lateral and median, jugular plates, situated between the rami of the mandible; caudal fin diphycercal, or heterocercal ; scales cycloid or rhomboid, smooth or sculp- tured.”—(Huxley.) All the Ganoids of this sub-order are pre-eminently dis- tinguished by the structure of the paired fins, the pectorals always, and the ventrals usually, consisting of a central lobe 140 ORDERS OF FISHES. or stem, which is covered by scales, and to the sides of which the fin-rays are attached. The nearest approach to this structure amongst living fishes is found in the paired fins of the Barramunda (Ceratodus Forsteri) of the rivers of Queens- land. In this singular fish, which is referable to the order of the Dipnoi, the pectoral and ventral fins are supported by a median, many-jointed, cartilaginous rod, to which numerous lateral branches are attached (fig. 489). The scales in this sub-order are sometimes rhomboidal, not overlapping one another; at other times they are cycloidal in shape, and are arranged in an imbricate manner. Professor Huxley, in his classical memoir upon the Fossil Ganoids, divides the Crossopterygideé into the following fam- ilies (see ‘Memoirs of the Geological Survey of Great Britain. Decade X.’) :— Fam. 1.—POLYPTERINI. Dorsal fin very long, multifid ; scales rhomboidal. Polypterus (fig. 500). Fam. 2.—SAURODIPTERINI. Dorsal fins two; scales rhomboidal, smooth ; fins sub-acutely lobate. Diplopterus, Osteolepis (fig. 500), Megalichthys. Fam. 3.—GLYPTODIPTERINI. Dorsal fins two; scales rhomboidal or cycloidal, sculptured ; pectoral fins acutely lobate ; dentition dendrodont. Sub-fam. A. with rhomboidal scales. Glyptolemus (fig. 506), Glyptopomus, Gyroptychius. Sub-fam. B. with cycloidal scales. Holoptychius (fig. 507), Glyptolepis, Platygnathus [Rhizodus, Dendrodus, Cricodus, Lamnodus ]. Fam. 4.—CTENODIPTERINI. Dorsal fins two; scales cycloidal ; pectorals and ventrals acutely lobate ; dentition ctenodont. Dipterus [Ceratodus 2? Tristichopterus ?] Fam. 5.—PHANEROPLEURINI. Dorsal fin single, very long, not subdivided, supported by many interspinous bones ; scales thin, cycloidal; teeth conical, ven- tral fins very long, acutely lobate. Phaneropleuron (fig. 510). ORDERS OF FISHES. 141 Fam. 6.—C@LACANTHINI. Dorsal fins two, each supported by a single interspinous bone; scales cycloidal ; paired fins obtusely lobate ; air - bladder ossified. Celacanthus, Undina, Macropoma. As regards the above arrangement of the Crossopteryqide, the chief change which has been effected by recent researches relates to the group of the Ctenodipterim. Thus, it has been shown that Ceratodus and Dipterus are not only closely allied to one another, but that the former is related to Lepidosiren by characters which appear to have an ordinal value. 7ris- tichopterus, on the other hand, has been shown by Traquair to belong to the cycliferous division of the Glyptodipterini. The result of this is that the group of the Ctenodipterini must be removed from association with the Crossopterygious Ganoids, and must stand in future as a section of the order Dipnoi. The only alternative step is to reduce the Dipnoi from the rank of an order to that of a mere section of the Ganoider. The present condition of our knowledge of this subject will probably be best expressed if we subjoin here the following table, showing the classification of the Crossop- terygide proposed by Dr Traquair (Trans. Roy. Soc. Edin., vol. xxvii.) :— Section I.—Caudal diphycercal, but with shortened body-axis. Dor- sal fin multifid, pectorals obtusely lobate, scales rhomboidal. Fam. 1.—Polypteride (Polypterus, Calamoichthys). Section IT.—Caudal with elongated attenuated body-axis, heterocercal or diphycercal. A. Pectorals obtusely lobate, tail diphycercal, dorsal fins two, scales cycloidal, air-bladder ossified. Fam. 2.—Ceelacanthide (Celacanthus, Macropoma, Holophagus). B. Pectorals sub-acutely lobate, dorsal fins two, tail heterocercal or diphycercal. a. Scales rhomboidal. Fam. 3.—Rhombodipteride. * Scales sculptured. Sub-fam.—Glyptolemini (Glyptolemus, Glyp- topomus). ** Scales smooth. 142 ORDERS OF FISHES. Sub-fam.—Saurodipterini (Osteolepis, Diplop- terus, Megalichthys). b. Scales eycloidal, sculptured. Fam. 4.—Cyclodipteridee (T'ristichopterus, Gyro- ptychius (2), Rhizodus, Rhizodopsis, Strepsodus, Archichthys (7?) ). C. Pectorals acutely lobate, scales cycloidal, a. Dorsal fins two, ventrals sub-acutely lobate, scales thick, sculptured. Fam. 5.—Holoptychiidee (Holoptychius, Glyptolepis, Dendrodus (?), Cricodus (2) ). b. Dorsal fin elongated, continuous with the upper part of the caudal; ventral fins acutely lobate; scales thin. Fam. 6.—Phaneropleuride (Phaneropleuron, Uro- nemus). As regards the distribution of the Crossopterygide in time, Professor Huxley remarks: “Of the six families which compose it, four are not only Paleozoic, but are, some ex- clusively, and all chiefly, confined to rocks of Devonian age an epoch in which, so far as our present knowledge goes, no fish belonging to the sub-orders of the Amiadw and Lepidosteide (unless Cheirolepis be one of the latter) makes its appearance. Rapidly diminishing in number, the Crosso- pterygids seem to have had several representatives in the Carboniferous epoch ; but after this period (unless Ceratodus be a Ctenodipterine) they are continued through the Mesozoic age only by a thin, though continuous, line of Ccelacanthini, and terminate, at the present day, in the two or three known species of the single genus Polypterus.” Of the extinct types of this sub-order, some are sufficiently important to merit especial mention. In the family of the Saurodipterini, the genus Osteolepis (fig. 500) has a very heterocercal tail and smooth scales. The first dorsal is placed near the centre of the back, and the mouth is fur- nished with sharp teeth. All the species of this genus are Devonian. The Carboniferous genus Megalichthys appears also to belong here. In this singular genus are large “ sau- roid” fishes with heterocercal tails, rhomboidal scales, and great conical incurved teeth, which are mostiy smooth, but are sometimes finely ridged. ORDERS OF FISHES. 143 Of the Glyptodipterini with rhomboidal scales, Glyptolemus (fig. 506) may be taken as the type. In this singular fish, the body is elongated and the head depressed. There are two dorsal fins which are placed very far back, and the ventrals have a similar posterior position. The tail is “divided into two equal lobes by the prolonged conical termination of the body,” becoming thus “diphycercal.” Glyptolemus is ex- clusively confined to the Devonian period. Fig. 506.—Glyptolemus Kinnairdi. Restored. a, Scale of the same. Devonian. Of the Glyptodipterines with cycloidal scales, the most important form is Holoptychius (fig. 507). In this genus there are two dorsal fins placed very far back, and the ven- Fig. 507.—Holoptychius nobilissimus. Restored. a, Scale of the same. Devonian. trals are similarly approximated to the tail, as in Glyptolemus ; while the pectorals are similarly acutely lobate. The body, however, is covered with large scales of a cycloidal form, which overlap one another, and have wrinkled surfaces ; and the tail is inequilobed. The teeth are of two sizes, and the larger ones are longitudinally striated at their bases. The true Holoptychii are Devonian in their distribution. In 144 ORDERS OF FISHES. the Carboniferous rocks, however, occur the superficially similar forms which constitute the genus Rhizodus (fig. 508), in which the teeth agree with those of Holoptychius in being of two sizes, but differ in being trenchant on both sides. The genus, again, differ from Holoptychius, and ap- proaches Megalichthys, in having an obtusely-lobate pectoral fin, as is also the case in the allied Riizodopsis. Rhizodus must have attained a large size, and must have been highly predaceous in its habits. Fig. 508.—Jaw of Rhizodus Hibberti. Carboniferous. We may also provisionally place near Holoptychius the genus Onychodus, from the Devonian of North America. In this genus are Ganoid fishes of large size having the cranium covered with bony plates, the surface of which is enamelled and tuberculated. The jaws carry numerous conical recurved teeth; and the scales (fig. 509) resemble those of Holoptychius in being cycloidal and overlapping, the under surface con- centrically striated, and the exposed portion of the upper surface adorned with tubercular wrinkles. We may further place here the so- Fig. 509.—Upper surface of called “ Dendrodont” Ganoidsmi(@en- a scale of Onychodus sigmoides, of the natural size, from the drodus, Cricodus, &c.), which are espe- Devonian of North America. . wihis é (After Newberry.) cially distinguished by the fact that the teeth have a singularly complicated and labyrinthine microscopic structure, somewhat resembling the pattern of the teeth in the Amphibian order of the Labyrinthodontia. The Dendrodonts are Devonian in their range, ORDERS OF FISHES. 145 The family Phanopleuwrint comprises only the single genus Phaneropleuron (fig. 510), which is probably exclusively De- vonian. In this singular genus the scales are very thin, eycloidal, and overlapping one another. The dorsal fin is extremely long, and is confluent with the tail-fin, and the pectorals and ventrals are acutely lobate. The jaws are armed with a single series of short conical teeth, and the notochord was persistent. Fig. 510.—Phaneropleuron Andersoni and scale. Devonian. Lastly, the family of the Calacanthini comprises forms which range from the Devonian to the Cretaceous period, and which are distinguished, in the typical genera, by having hollow fin-spines, by the possession of two dorsal fins, each supported by a single interspinous bone, by having cycloidal overlapping scales, and by the remarkable peculiarity that the swim-bladder was ossified. The type-genus Cwlacanthus seems to range from the Carboniferous to the Trias. SUB-ORDER KE, ACANTHODIDA.—NScales exceedingly small, shagreen-like ; the front of each fin provided with a strong spine, simply implanted in the flesh; no distinctly ossified cranial bones; no operculum; tail heterocercal. In their fin-spines, and in some other points, the Acanthodide ap- proximate closely to the Hlasmobranchui ; but they are gener- ally regarded as an order of the Ganoidei. The Acanthodidw are mainly Devonian, but some forms occur in the Carbon-. iferous rocks, and two species from the Permian rocks have VOL. ir K 146 ORDERS OF FISHES. been described. Acanthodes has a single dorsal fin, and is represented in both Devonian and Carboniferous deposits. Cheiracanthus (fig. 511, 1), of the Old Red Sandstone, is very similar to Acanthodes, but the single dorsal fin is placed in front of the anal. Diplacanthus (fig. 511, 3) has two dorsal fins, and is exclusively confined to the Devonian rocks. is Ss SALAS Fig. 511.—1, Cheiracanthus Murchisoni ; 2, Climatius scutiger ; 3, Diplacanthus gracilis, Devonian. Sus-orRDER F. OstracostE!1.—The Ganoids of this sub- order, commonly known as “ Placoderms,” are characterised by having the head, and generally the anterior portion of the trunk as well, encased in a strong armour composed of numerous large ganoid plates, immovably united to one another. The posterior extremity of the body is more or less completely unprotected; and whilst the notochord is persistent, the peripheral elements of the vertebree may be ossified. The fishes belonging to this section—dif the piscine nature of the “Conodonts” be denied—are the most ancient of their class, commencing in the Upper Silurian rocks. They extend through the Devonian series, but are not known to have survived into the Carboniferous period. They have generally been placed amongst the Ganoids; but Professor Huxley has pointed out that they present, many of them, features by which they approximate ORDERS OF FISHES. Ay closely to the Siluroids amongst the Teleosteans. The more important genera included in this sub-order are Cephalaspis, Pteraspis, Coccosteus, and Pterichthys. Cephalaspis (fig. 512) is the type of the family of the Cephalaspide, and is readily recognised by the fact that the cephalic shield has its posterior angles produced into long Fig. 512.—Cephalaspis Lyellii. (After Page.) Old Red Sandstone. “cornua,” giving it the shape of a “saddler’s knife.” Besides these lateral cornua, there is a “ posterior cornu” or spine, formed by a prolongation backwards of the hinder margin of the shield in the middle line. The orbits are approximated, and are placed nearly in the centre of the cephalic shield. No jaws or teeth are known, and the mouth was probably soft, and adapted for suction. The head-shield exhibits vascular canals, and shows very distinct bone-cells when examined in thin sections under the microscope. The body is covered with ganoid scales, and there is a well-marked dorsal fin. Pectoral fins have also been described, and the tail is clothed with a heterocercal fin. In the nearly allied Auchenaspis, the structure is very similar to the above, but there is no spine or “ posterior cornu,’ and there is instead a neck-plate formed by an extension backwards from the cephalic shield. The Cephalaspidw are mainly found in the Old Red Sandstone, the commonest species being C. Lyellii. Other species are found in the “passage-beds” between the Silurian and Old Red, and the genus is not wholly unrepre- sented in the Upper Silurian deposits. The genus occurs not only in Europe, but also in the Devonian of North America. 148 ORDERS OF FISHES. In the genus Pteraspis (fig. 513) the head is defended, as in Cephalaspis, by a shield or buckler, which is composed of several pieces firmly anchylosed. The shield consists of a central disc, the Fig. 513. — Cephalic buckler of Pteraspis (Cy- athaspis) Bunksii. From the Upper Ludlow rocks of Ludlow. (After Mur- chison.) lateral angles of which are produced into short cornua, whilst it is extended into a rostrum in front. The posterior spine is very small, and is attached to the disc as a separate piece. The orbits are situated laterally. The minute structure of the shield is very complex, consisting of three layers. The innermost layer is laminated, and is traversed by vascular canals. The middle layer is made up of polygonal cavities; and the outer layer is struc- tureless or fibrous, and is finely striated or grooved. The body was covered with scales; but nothing is known of the nature of the fins. The genera Cyathaspis and Scaphaspis have been founded upon forms which have usually been placed under Pteraspis, and which differ in more or less essential points from the typical species of this genus. The genus Pteraspis, ela en Fig. 514.—Cephalic shield of Coccostews decipiens, viewed on one side, as restored by Pander —Old Red Sandstone. The surface-ornamentation is omitted, but a small portion is repre- sented at a, on a larger scale, so far as yet known, comprises the most ancient of the fishes, commencing as it does in the earlier portion of the Ludlow formation (Upper Silurian). Other species are known in the ORDERS OF FISHES. 149 Old Red Sandstone; but the genus appears to have entirely disappeared before the close of the Devonian period. In the genus Coccosteus (fig. 514) the head was protected by a great shield, the plates of which are covered with small hemispherical tubercles. There is also a ventral or “ sternal ” shield, which, according to Huxley, seems to have had no direct connection with the cephalic buckler. The mouth was furnished with a distinct lower jaw or “ mandible,” composed of two rami, carrying small teeth. The notochord was per- sistent, but the neural and hemal spines of the vertebrae, and the rays of the dorsal and anal fins, are well ossified. A heterocercal tail-fin was doubtless present as well. The genus Coccosteus is essentially Devonian; but a species has been discovered by M. Barrande in the Upper Silurian of Bohemia. In the genus Pterichthys (fig. 515) are some very remark- able fishes, first discovered in the Old Red Sandstone by the late Hugh Miller, and nearly related in most respects to Coc- Fig. 515.—Pterichthys cornutus. Old Red Sandstone. costeus. The whole of the head, together with the anterior part of the trunk, was defended by a buckler of large ganoid plates suturally united, those covering the trunk forming a backplate and a breastplate articulated together at the sides. The rest of the body was covered with small ganoid scales. A small dorsal fin, a pair of ventrals, a pair of pectorals, and a heterocercal tail-fin were present. The form of the pectoral fins is the peculiar characteristic of the genus. These were in the form of two long curved spines, somewhat like wings, covered by finely-tuberculated ganoid plates. From their form they cannot have been of much use in swimming ; but they probably, as suggested by Owen, enabled the animal 0 ORDERS OF FISHES. to shuffle along the sandy bottom of the sea, if stranded at low water. All the species of Plerichthys are exclusively confined to the Old Red Sandstone. If, however, Asterolepis of Pander be identical with Prerichthys, then the genus was represented in the Upper Silurian. We may also place in this neighbourhood the gigantic fishes of the Devonian of North America, for the reception of which Newberry has founded the genus Dinichthys. The head in this genus, sometimes measuring not less than three feet in length, was covered by a buckler of ganoid plates, resembling in form and arrangement the plates of the head- shield of Coccosteus, but having their surface adorned with granulations and furrows, in place of the stellate tubercles of the latter. The most remarkable feature in the genus, however, is the dentition, which closely resembles that of Lepidosiren, except in point of size, and which must have been associated with carnivorous and predaceous habits. Thus in the lower jaw (fig. 516) the extremity of each Fig. 516.—Diagram of the jaws and teeth of Dinichthys Hertzeri, viewed from the front, and greatly reduced in size. From the Devonian of North America. (After Newberry.) ramus is bent upwards and pointed, so as to form a huge and sharp tooth on each side; the margins of the mandible behind these being enamelled for some distance, forming a sharp cutting edge, which may be entire or serrated. In the upper jaw, the tooth-like ends of the mandibular rami are confronted by two great premaxillary teeth, of a triangular form, and the margins of the maxille on either side of these are either compressed and trenchant or actually denticulate. SUB-ORDER G, CHONDROSTEIDA (STURIONIDA).—In this sub- order the skeleton is almost altogether cartilaginous, and the notochord is persistent. The exoskeleton is usually in the form of large ganoid plates, which are united into a shield over the head, but are detached over the body. Sometimes ORDERS OF FISHES. 151 the exoskeleton is absent, and in no case is the mouth fur- nished with teeth. The tail is heterocercal. This sub-order comprises the living Sturgeons (fig. 491), and is not known with certainty to have come into existence before the Eocene Tertiary, where it is represented by the Acipenser toliapicus of the London Clay. In the Lias, how- ever, occur two species of the singular genus Chondrosteus, which have usually been referred here, and have been regarded as being most nearly allied to the Paddle-fishes (Spatularia) of North America. The skull, however, is more completely ossified than is the case with any lving members of the Sturionde ; and the true place of Chondrosteus must be regarded as uncertain. We may also place here, at any rate provisionally, the Devonian 4, 547 piacram of the skull genus Macropetalichthys, species of of Macropetalichthys Sullivanti, C : viewed from above, and greatly which are known to occur in both reduced in size. From the De- the Old and New Worlds. In this eee Cita genus are included large fishes, in which the skull is protected by large polygonal ganoid plates (fig. 517), the surface of which is enamelled and tuberculated. The orbits are of large size, and both scales and teeth appear to have been entirely wanting. CHAPTER XXXII. ORDERS OF FISHES (Continued). OrpDER III. ELASMOBRANCHI (= Selachia, Miiller ; Placoidez, Agassiz; Holocephali and Plagiostomi, Owen).—This order includes the Sharks, Rays, and Chimerz, and corresponds with the greater and most typical portion of the Chondrop- terygide or Cartilaginous fishes of Cuvier. The order is distinguished by the following characters: Zhe skull and lower jaw are well developed, but there are no cranial bones, and the skull consists of a simple cartilaginous box, without any in- dication of sutures. The vertebral column is sometimes com- posed of distinct vertebree, sometimes cartilaginous or sub-noto- chordal. The exoskeleton is in the form of placoid granules, tubercles, or spines. There are two pairs of fins, representing the limbs, and supported by cartilaginous fin-rays; and the ventral fins are placed far back near the anus. The pectoral arch has no clavicle. The heart consists of a single auricle and ventricle, and the bulbus arteriosus is rhythmically contractile, is provided with a special coat of striated muscular fibres, and is furnished with several transverse rows of valves. The gills are pouch-like. In most of the above characters it will be seen at once that the Elasmobranchit agree with the Ganoid fishes, espe- cially as regards the structure of the heart. The following points of difference, however, require more special notice :— 1. The exoskeleton is what is called by Agassiz “ placoid.” It consists, namely, of no continuous covering of scales or ganoid plates, but of more or less numerous detached grains, (SX) ORDERS OF FISHES. 15 tubercles, or spines, composed of bony or dentinal matter, and scattered here and there in the integument. In the case of the Rays, these placoid ossifications often take a very singular shape, consisting of an osseous or cartilaginous disc, from the upper surface of which springs a sharp recurved spine, composed of dentine. The so-called “shagreen” of the Dog-fishes and Sharks is composed of very small and close-set tooth-like processes. At other times the placoid structures are developed into “dermal defences” or “ ichthyo- dorulites.” The minute structure of these exoskeletal struc- tures is closely or entirely similar to that of the teeth. In some cases the exoskeleton is absent. 2. The gills are fixed and pouch-like, and differ very materially from those of the Bony and Ganoid fishes. In the case of the Sharks and Rays, the gill-pouches open upon the surface by a series of separate apertures, which are placed on the sides of the neck in the former, and on the under surface of the body in the latter. In neither is there any gill-cover or operculum, nor are there any branchiostegal rays. In one section of the order, however—viz., the Holo- cephalithough the internal structure of the gills is essen- tially the same as in the Sharks, there is only a single branchial aperture or gill-slit externally, and this is pro- tected by a rudimentary operculum and branchiostegal rays. The order Elasmobranchii is divided into the two sub- orders of the Holocephali and Plagiostomi. The former comprises the living Chimere, characterised by the mouth being terminal, and by there being only a single gill-slit. The latter comprises the living Port Jackson Shark, the true Sharks and Dog-fishes, and the Rays, characterised by havy- ing the mouth transverse and placed on the under surface of the head, whilst there are several apertures to the gills. As regards their general distribution in time, the Elasmo- branchit are nearly as ancient as the Ganoids. At the top of the Upper Ludlow rocks, or at the close of the Upper Silurian epoch, there have been discovered the remains of undoubted Plagiostomous fishes, most nearly allied to the existing Port Jackson Shark (Cestracion Philippi). These remains consist chiefly of defensive spines, which formed the 15: ORDERS OF FISHES. first rays in the dorsal fins, and upon these the genus Onchus (fig. 520) has been founded. Besides these there have been found portions of skin or “shagreen,” with little placoid tubercles, like the skin of a living shark. These have been referred to the genera Sphagodus and Thelodus. They are the earliest known remains of Plagiostomous fishes, and with the exception of the few remains from the Lower Ludlow rocks, they are the earliest known remains of fishes in the stratified series. The discovery of these remains, at that time the earliest known traces of Vertebrate life, is due to the genius of Sir Roderick Murchison, the author of ‘ Siluria.’ Most of the fossil Llasmobranchit belong to the division Cestraphort of Owen, so called because they are provided with the large fin-spines which are known to geologists as “ichthyodorulites.” The two families of this division—the Cestracionts and Hybodonts—are largely represented in past time, the former chiefly in the Paleozoic period, the latter chiefly in the Mesozoic rocks. The true Sharks are represented in the earlier Mesozoic deposits (¢.g., by teeth of Notidanus in the Oolites) ; but they are chiefly Cretaceous and Tertiary. The teeth of Odontaspis, Galeocerdo, and Carcharodon, are good examples from the Eocene of the Isle of Sheppey. The true Rays are older than the true Sharks, occurring as early as the Carboniferous. Numerous remains of Rays, chiefly in the form of the pave- ment-like teeth, are known, both from the Secondary and Tertiary rocks. The last division of the Hlasmobranchuu— viz., that of the Holocephali—is poorly represented in past time by the Rhynchodus of the Devonian, and by the Mesozoic and Kainozoic Jschiodus, Elasmodus, Ganodus, and Edaphodus. In the following a more detailed account is given of the characters of the various groups of the Elasmobranchii with the leading characters and more important fossil forms of each :— SUB-ORDER A. HoLocEPHALI.—This sub-order includes certain curious fishes, of which the only living forms are the Chimeride. The notochord is persistent, but the neural arches and transverse processes are cartilaginous. The jaws ORDERS OF FISHES. ILS) are bony, and are covered by broad plates representing the teeth. The exoskeleton consists of placoid granules. The first ray of the anterior dorsal fin is in the form of a power- ful defensive spine, like the “ichthyodorulites” of many fossil fishes. The ventral fins are abdominal, and the tail is heterocercal. There is only a single external gill-aperture, covered with a gill-cover and branchiostegal membrane ; but only a small portion of the borders of the branchial laminze is free. The mouth is placed at the extremity of the head. The earliest known remains of Chimeeroid fishes are those which Newberry has described from the Devonian of North America under the name of Rhynchodus, and (unless we place here the Devonian Ptyctodus, which may perhaps belong to a Dipnoan) they are the only traces of this group as yet found in the Paleozoic rocks. The remains upon which this genus is based consist of crescent-shaped or semi- circular dental plates, the straight side of the tooth forming a triturating or cutting edge. In the Mesozoic and Kaino- zoic deposits, the remains of Chimeroids are not extremely rare, but they consist only of the jaws and teeth, along with fin-spines or “ichthyodorulites.” The dental plates are united to the beak-shaped jaws (fig. 518); and the dorsal fin-spines are always movable and jointed—ainstead of being Fig. 518.—Lower jaw of Edaphodus gigas, viewed from above, showing the dental plates. Tertiary. (After Sir Philip Egerton.) supported on a cartilage embedded in the muscular tissue of the back (as in the Spinacide and Cestraciontide). Of the fossil Chimeeroids, the genera Jschiodus and Ganodus are ex- clusively Mesozoic ; Hdaphodus ranges from the Cretaceous 156 ORDERS OF FISHES. series to the Eocene Tertiary ; and Hlasmodus is only known . from the Eocene. SuB-ORDER B. PLacrostoMI.—This sub-order is of con- siderably greater importance, as it includes the well-known Sharks and Rays. The vertebral centra are usually more or less ossified, and even when quite cartilaginous, the centra are marked out by distinct rings. The skull is in the form of a cartilaginous capsule, without distinct cranial bones. The mouth is transverse, and is placed on the under surface of the head. The exoskeleton consists of placoid granules, tubercles, or spines. The branchial sacs open externally by as many distinct apertures as there are sacs, and there is no operculum. By Professor Owen the Plagiostomi are divided into three sections, termed respectively the Cestraphori, the Selachit, and the Batides. Kx EES = i Zz ZY, NA IWss 4 Wi wed Middle Permian rocks, species of which at- tain a length of four feet or more, and have been found at the same geological horizon in both Europe and Britain. Protorosaurus differs from all existing Lizards in having its teeth implanted in distinct sockets—this being a Crocodilan character. In other respects, the Permian reptile approximates closely to the living Monitors (Varanide), and its slightly- cupped vertebree would lead to the belief that it was aquatic in its habits. In rocks known, or supposed, to be of Triassic age, numerous Lacertilian reptiles have been discovered, of which the most im- portant are Telerpeton, Hyperodapedon, and Telerpeton occurs in strata near Elgin, in Scotland, which have been variously referred to the Upper REPTILIA. L083 Devonian and to the Trias, but which almost certainly belong to the latter. Professor Huxley concludes that Zelerpeton “pre- sents not a single character approximating it towards the type of the Permian Protorosawria, nor to the Triassic Rhyn- chosaurus, and other (probably Triassic) African and Asiatic allies of that genus, nor to the Mesozoic Dinosauria ; still less can it be considered a ‘ generalised’ form, or as, in any sense, a less perfectly organised creature than the Gecko, whose swift and noiseless run over walls and ceilings sur- prises the traveller in warmer climates than our own.” In its dentition, Zelerpeton seems to have been “ acrodont,” and it differs from most existing Lizards merely in having am- phiccelous, and not proccelous, vertebree. Hyperodapedon was originally discovered in the “ Elgin Sandstones” along with Telerpeton, and it has since been found in strata of Triassic age in India. It was described by Professor Huxley as “a Saurian reptile about six feet long, remarkable for the flattened or slightly concave artic- ular surfaces of the centra of its vertebre, and for its well- developed costal system and fore and hind limbs; but more particularly characterised by its numerous series of sub- cylindrical palatal teeth.’ Upon the whole, Huxley con- cludes that Hyperodapedon is most nearly allied to the living Sphenodon (Hatteria) of New Zealand (fig. 554), upon the Fig. 554.—Side view of the skull of Sphenodon (Hatteria) punctata, the lower jaw being removed. (After Giinther.) erounds that both “have amphiccelous vertebree (those of the ancient reptile being far less fish-hke than those of the modern one, be it noted); both have beak-hke premaxille, not anchylosed together; both have the inferior zygoma 204 REPTILIA. complete ; both have similarly-formed lower jaws; in each a single row of teeth in the mandible bites between two rows of teeth fixed to a plate, which is formed by a union of the maxilla with the palatine bone—a structure which is quite anomalous amongst Lacertilians ; and finally, in both, these teeth wear down to the bone of the jaw by masticatory attrition.” From its relations with the Triassic Hyperodapedon, as well as on account of its own peculiarities, the living Sphenodon possesses a special niterest for the paleontologist. In this extraordinary form—the sole remaining representative of the Lacertilian family of the Rhynchocephalia—the vertebre are amphiccelous, and some of the ribs bear “ uncinate processes ” similar to those of Birds. The quadrate bone is not mov- able, and is united by suture with the skull. The teeth are completely amalgamated by anchylosis with the jaws, and are developed in the mandible, preemaxille, and in a lonei- tudinal series upon the palatine bones. The premaxillary teeth are two in number, and are of large size and scalpri- | form in shape (fig. 554). The serrated edge of the mandible is received in the groove between the palatine teeth and the cutting edges of the maxill, the alveolar borders of which are hard and as highly polished as the teeth themselves, the function of which they discharge when the latter are ground down in advanced age. The genus Lhynchosaurus is in a doubtful position, but may also conveniently be considered here. By Huxley its affinities are regarded as being Lacertilian, but by Owen it is looked upon as belonging to the Anomodontia, and as being most nearly allied to Oudenodon. In many points Rhynchosaurus ap- ig ca Ge ns wt »roaches the existing Lizards, but its vertebre are amphicce- lous, and the structure of the mouth is quite unlike that of any living Lacertilian. The skull (fig. 555) is pyramidal, and the jaws do not exhibit any traces of teeth. If the mouth be really edentulous, then Rhynchosawrus should prob- REPTILIA. 20d ably be removed from the Lagertilia ; but this point cannot in the meanwhile be definitely decided in the affirmative. Amongst other Triassic, or supposed Triassic, Lacertilians, may be mentioned Sawrosternon and Pristerodon, from strata believed to be of Triassic age in Africa, and Centemodon from deposits of the same age in North America. In the Jurassic period the remains of Lacertilians are not very uncommon, but call for little special notice. Several forms of little importance have been described from the Middle Oolites. In the fresh-water strata of the Purbeck series (Upper Oolites), occur the remains which have been referred to the genera Nuthetes, Macellodon, Sawrillus, and Echinodon. These are, perhaps, the first traces in the strati- fied series of remains, the affinities of which to the typical Lacertide cannot be disputed. | In the Cretaceous series occur the small Lizards which constitute the genera Raphiosaurus, Coniosaurus, and Doli- chosaurus. Here also, and almost exclusively confined to strata of this age, occur the singular Lacertilians which form the group of the “Mosasauroids ” (Mosasauride). These re- markable Reptiles were of gigantic size, Mosasaurus princeps Fig. 556.—Skull of Mosaswurus Camperi, much reduced. Maestricht Chalk. being believed to have attained the enormous length of not less than seventy-five feet. Originally referred to the Ceta- cea (Camper), and subsequently regarded as Crocodilian, the 206 REPTILIA. Mosasauroids were first placed among the Lacertilians by Professor Owen, and the view entertained by this distin- guished comparative anatomist of their real affinities is now generally accepted. Professor Cope, however, considers these Reptiles to form—under the name of Pythonomorpha—a croup allied to the Ophidia. The body in the Mosasauroids is greatly elongated, the vertebree being proccelous, and sometimes provided with a zygosphene and zygantrum. The teeth (fig. 556) are long, pyramidal, and shehtly curved; but they are anchylosed to the jaw, and are not sunk into distinct sockets, as in the living Crocodiles. The condition of the integument is. un- known in many forms; but Marsh has recently shown that osseous dermal scutes are present in some forms (¢. g., Holcodus, Leto- don, and Edestosaurus), and we may reasonably infer the presence of a similar armature in other members of the group. It is not known, however, how much of the surface was thus protected, though it would appear that the head was certainly not defended by scutes. From the shortness of the humerus, and the indications that the vertebral column was unusually flexible, and that the tail was laterally compressed, it was early conjectured that the Mosa- sauroids were marine and aquatic in their habits. This conjecture has been raised to the rank of a Fig. 557.—Right anterior paddle certainty by the discovery that the of Lestosaurus simus, one-twelfth of the natural size. (After Marsh.) fore and hind limbs of the Mosa- a, Scapula; b, Coracoid; c, Hu- C 4 n O merus; d, Radius; e, Ulna. sauroids were in the form of fin-like paddles (fig. 557), like those of the Ichthyosaur and Plesiosaur, but having the digits distinct. There can therefore be no doubt that Mosasauwrus—like the living Amblyrhynchus—was aquatic in its habits, and fre- quented the sea-shore, coming, in fact, only occasionally to the REPTILIA. ZOMG land. The best-known genus is Mosasaurus, of which the most celebrated species is the JZ, Camperi (fig. 556) of the Maes- tricht Chalk. Other genera belonging to this group are Leiodon, Tylosaurus, Lestosaurus, Clidastes, &c. The entire group, so far as at present known, is confined to the Creta- ceous rocks, and though represented in Europe, it seems to have had its maximum development in the North American area. In the Tertiary rocks the remains of Lacertilians are not by any means unknown, but none of the forms of this period are sufficiently important to demand especial attention. Most of the Tertiary Lacertilians, however, are of small size, and appear to have been terrestrial in their habits, thus approxi- mating to the typical existing Lizards. The most remark- able group of the Tertiary Lizards, however, is that of the Glyptosauride (Glyptosaurus, and Oreosaurus), comprising forms which are found in the Eocene Tertiary of North America, and have the anomalous character that the skin was furnished with ornamented osseous scutes. It is also worthy of notice that while the Tertiary Lizards are refer- able for the most part to actually existing groups, the recent genus Chameleo seems to have been in existence as early as the Eocene. OrpDER IV. CrocopiLiA.—The last and highest order of the living Reptilia is that of the Cvrocodilia, including the living Crocodiles, Alligators, and Gavials,-and characterised by the following peculiarities :— The body is covered with an outer epidernic exoskeleton com- posed of horny scales, and an inner dermal exoskeleton consisting of transverse rows of squared bony plates or scutes, which may be confined to the dorsal surface alone, or may exist on the ventral surface as well, and which are disposed on the back of the neck into groups of different form and number in certain species. The bones of the skull and face are firmly united together, and the two halves or rami of the lower gaw are united in front by a suture. There is a single row of teeth, which are vinplanted in distinct sockets, and are hollowed at the base for the germs of the new teeth, by which they are successively pushed out and re- placed during the life of the animal. Zhe centra of the dorsal 208 REPTILIA. vertebre in all living Crocodilia are procelous, or concave in front, but in the extinct forms they may be either amphiccel- ous (concave at both ends) or opisthoccelous (concave behind). The vertebral ends of the anterior trunk-ribs are bifurcate. There are two sacral vertebrae. The cervical vertebree have small ribs; and there are generally false abdominal ribs pro- duced by the ossification of the tendinous intersections of the vectt muscles. There are no clavicles. The heart consists of four completely distinct and separate cavities. All the four limbs are present, the anterior ones being pentadactylous, the posterior tetradactylous. All are oviparous. The chief points by which the Crocodiles are distinguished from their near allies the Lacertilians, are the possession of a partial bony dermal exoskeleton in addition to the ordinary epidermic covering of scales, the lodgment of the teeth in distinct sockets, and the fact that the mixture of venous and Fig. 558.—a, Head and anterior portion of the body of Crocodilus pondicerianus ; B, Hind-foot of the same. (After Gunther.) arterial blood, which is so characteristic of Reptiles, takes place, not in the heart itself, but in its immediate neighbour- hood, by a communication between the pulmonary artery and aorta directly after their origin. REPTILIA. 209 When the exoskeleton is complete (as in Teleosawrus and in Caiman), it consists of transverse rows of quadrate bony plates disposed so as to form a distinct dorsal and ventral shield, which are separated by soft skin in the region of the trunk, but become confluent in the tail. All the scutes of one row are united by suture, and successive rows usually movably overlap one another. The order Crocodilia is divided by Owen into three sub- orders, termed Procelia, Amphicelia, and Opisthocelia, accord- ing as the dorsal vertebree are concave in front, concave at both ends, or concave behind! The sub-order Procelia com- prises all the living forms—namely, the Crocodiles proper, the Alligators, and the Gavials. The first of these have the fourth tooth in the lower jaw (fig. 559) larger than the others, forming a canine tooth, which is received into a notch excavated in the alveolar border of the upper jaw, so that it is visible externally when the mouth is closed. In the Alligators (fig. 560), the fourth tooth in the lower jaw forms a canine which is received into a pit in the palatal surface of the upper jaw, where it is completely concealed when the mouth is shut. In the Gavials the snout is greatly prolonged, 1 The following more elaborate classification of the recent and extinct Croco- dilia has been proposed by Professor Huxley :— I, PARASUCHIA, with no bony plates of the pterygoid or palatine bones to prolong the nasal passages; the Eustachian passages enclosed by bone; the centra of the vertebree amphiccelian; the coracoid short and rounded; the ala of the ilium high, and its acetabular margin entire; and the ischium short dorso-ventrally and elongated longitudinally, with its acetabular portion re- sembling that of a Lizard.—Genera: Stagonolepis, Belodon. II. MrsosucuiA, with bony plates of the palatine bones prolonging the nasal passages, and giving rise to secondary posterior nares; a middle Kus- tachian canal included between the basioccipital and basisphenoid, and the lateral canals represented only by grooves; vertebral centra amphiceelian ; coracoid elongated ; ala of the ilium lower than in the preceding, higher than in the next sub-order, its acetabular margin nearly straight; ischium more elongated dorso- ventrally than in the preceding group, with its acetabular margin deeply notched. — Genera: Steneosaurus, Pelagosawrus, Teleoswurus, Teleidosaurus, Metriorhynchus (Goniopholis ? Pholidosaurus ?), III. Eusucuta, with both pterygoid and palatine bones giving off plates which prolong the nasal passages ; vertebral centra mostly proccelous ; coracoid elongated ; ala of the ilium very low in front, its acetabular margin deeply notched ; ischium elongated dorso-ventraliy, with its articular margin deeply excavated.—Genera: T'horacosaurus, Holops, and the recent forms. VOI in: O 210 REPTILIA. and the teeth are pretty nearly equal in size and similar in form in the two jaws. Fig. 559.—Skull of the Crocodile. The first appearance of Procelian Crocodiles, so far as known, is in the upper portion of the Cretaceous series of North America, where they are represented by the genera Lottosaurus, Holops, and Thoracosaurus, all of which are pe- j a ea \, ‘tu au Fig. 560.--Upper jaw of Alligator. Eocene Tertiary, Isle of Wight. culiar to this formation. In Europe, however, the earliest remains of Proccelian Crocodiles are from the Lower Tertiary rocks (Eocene). It is a curious fact that in the Eocene rocks of the south-west of England, there occur fossil remains of all the three living types of the Cvocodilia—namely, the Gavials, true Crocodiles, and Alligators ; though at the pres- REPTILIA. 2pileil ent day these forms are all geographically restricted in their range, and are never all associated together. It is also a singular fact that the genus Gavialis, now entirely Asiatic in its distribution, should occur in the North American area in deposits as old as the Eocene Tertiary. The Amphicelian Crocodiles are characterised by their biconcave vertebre, and are entirely extinct, being confined altogether to the Mesozoic period. The biconcave vertebree show a decided approach to the structure of the backbone in fishes; and as the rocks in which they occur are mostly marine, there can be little doubt but that these Crocodiles were, in the majority of cases at any rate, inhabitants of the sea. Others, however, which are found in fresh-water de- posits or estuarine accumulations, probably resembled the existing Crocodiles in principally frequenting rivers. From - a paleontological point of view the Amphiccehan Crocodiles are much the most important group of the order Crocodilia, as they are, also, its most ancient representatives. The earliest types of the Amphicelia, and therefore of the order Crocodilia, are the Stagonolepis and Belodon of the Trias. The affinities of the former genus have been worked out by Prof. Huxley, who has shown that Stagonolepis resembled the existing Caimans in general form, but that it possessed the elongated skull of the Gavials. The body was protected by a ventral and dor- sal series of bony, pitted scutes, but there were only two rows of the latter; and the teeth have obtusely-pointed crowns, which some- times show signs of having been subjected aie aalte to attrition. In Belodon, on the other hand, of Belodon carotin- the teeth (fig. 561) are long, pointed, and (oejimes Noth conical, slightly curved, and longitudinally striated. The jaws were greatly elongated, as in the exist- ing Gavials. In the Jurassic series the remains of Amphiccelian Croc- odiles are abundant, and belong to such genera as Steneosaurus, Teleosaurus, Makrospondylus, Pelagosaurus, Metriorhynchus, &e. The first two of the forms mentioned above are the most 2 lee REPTILIA. important and the most widely distributed. Of these, Zeleo- saurus is a well-known Mesozoic type, represented by many Jurassic species, and having the jaws greatly elongated, and carrying numerous conical teeth, as in the living Gavials. The dermal scutes are large and exceptionally strong and solid. The Jurassic genus Steneosaurus (fig. 562) also com- prises Jurassic Crocodilans, which, except for their amphiccelous ver- tebree, have many points of re- semblance to the existing Gavials. In the Cretaceous rocks, lastly, and especially in the estuarine de- posits of the Wealden, we have various types of Amphiccelian Cro- codiles, such as Goniopholis, Pholi- dosaurus, and Diplosaurus. The genus Hyposauvrus is found in the Cretaceous of North America, and its species resemble in form the modern Gavials. We may briefly consider here a eroup of Reptiles which have been regarded as Crocodihan, but which are placed by Owen in a separate order under the name of Zheco- dontia, and which are looked upon by Huxley as being Deinosaurian. The “ Thecodont” Reptiles are de- fined as follows: ‘“ Vertebral bodies ai ete SE ee Aa biconcave ; ribs of the trunk long verti, viewed from above. Jurassic. and bent, the anterior ones with a Actual length about three feet and a = half. (After Morel de Glasville,) bifureate head; sacrum of three vertebre ; limbs ambulatory, femur with a third trochanter. Teeth with the crown more or less compressed, pointed, with trenchant and finely serrate mar- gins, implanted in distinct sockets.”—(Owen.) Omitting Selodon, now generally regarded as Crocodilian, the Thecodont Reptiles are the Thecodontosaurus and Paleo- saurus (fig. 563) of the Trias. These were orginally based REPTILIA, 213 upon detached teeth found in a dolomitic conglomerate near Bristol, which has sometimes been supposed to be of Permian age, but which appears to be undoubtedly referable to the Trias. Teeth having the same generic char- acters have also been brought to ight in the Triassic deposits of North America. In some respects the Thecodont Reptiles make an ap- proach to the Lacertilians, while in others they approximate to the Deinosauria. Upon the whole, however, they would seem to be —™ ‘ 5 Fig. 563.—Tooth of best regarded as an ancient group of Amphi- = Pateosaurus platyo- ccelian Crocodiles, distinguished by their com- “2 78s: But pressed, trenchant, and serrated teeth. Lastly, the sub-order of the Opisthocelian Crocodiles, in- cluding those forms in which the anterior trunk vertebree are concave behind, is one which can be only provisionally retained. Professor Owen includes in this section the two genera Streptospondylus and Cetiosaurus; but the latter is referable to the Deinosawria, and will be treated of when that order is considered. The genus Streptospondylus has been founded on vertebree obtained from the Oolitic and Wealden formations; but there are doubts as to the true position of the Reptile to which these belonged. CHAPTER ~ XXXy- EXTINCT ORDERS OF REPTILES. It remains now to consider briefly the leading characters of six wholly extinct orders of Reptiles, the peculiarities of which are very extraordinary, and are such as are exhibited by no living forms. OrDER V. ICHTHYOPTERYGIA, Owen (= Jchthyosauria, Hux- ley).—The gigantic Saurians forming this order were distin- euished by the following characters :— The body was fish-like, without any distinct neck, and prob- ably covered with a smooth or wrinkled skin, no horny or bony exoskeleton having been ever discovered. The vertebre were nu- merous, deeply biconcave or amphicelous, and having the neural arches united to the centra by a distinct suture. The anterror trunk-ribs possess bifurcate heads. There is no sacrum, and no sternal ribs or sternum, but clavicles were present as well as an interclavicle (episternum); and false ribs were developed im the walls of the abdomen. The skull had enormous orbits separated by a septum, and an elongated snout. The eyeball was pro- tected by a ring of bony plates in the sclerotic. The teeth were not lodged in distinct sockets, but in a convmon alveolar groove. The fore and hind limbs were converted into swimming-paddles, the ordinary number of digits (five) remaining recognisable, but the phalanges being greatly increased in number, and marginal ossicles being added as well. A vertical caudal fin was in all probability present. The order Jchthyopterygia includes only the gigantic and fish-like Ichthyosauri (fig. 564), all exclusively Mesozoic, EXTINCT ORDERS OF REPTILES. 215 and abounding in the Lias, Oolites, and Chalk, but especially characteristic of the Lias. As itself forming the order, the essential characters of Ichthyosaurus are those above given. In all the species of the genus, the head is of proportion- hee blip - SS Lue pa Fig. 564.—Ichthyosaurus communis, Lias. ately gigantic size, not separated from the trunk by a dis- tinct neck, and prolonged anteriorly into a huge snout, the jaws carrying a formidable array of conical teeth. The orbits are of immense size, and the small apertures of the nostrils are situated close beside them. The vertebral column is long, and there is a long series of ribs, extending from the neck to the tail, but none of them united in front with a sternum. The absence of a breast-bone, however, is compensated for by the development of a number of trans- verse curved bones, which strengthen the abdominal walls, and each of which consists of a median section and of three or more overlapping pieces on each side. The vertebral centra are deeply amphiccelous, the transverse and articular pro- cesses being rudimentary, while the neural arches have for the most part only a cartilaginous connection with the bodies of their respective vertebre ; so that the latter are commonly found in a fossil condition in a perfectly detached state. Beneath the caudal vertebrae are placed V-shaped “ chevron- bones.” | The pectoral arch (fig. 565, A) consists of a T-shaped interclavicle, with a clavicle, coracoid, and scapula on each side, the coracoids being of large size. The pelvic arch (fig. 565, B)—there being no sacruam—is not directly connected with the spine; but the pubic and ischial bones unite by symphysis. Both the pectoral and pelvic limbs are in the form of paddles, the former being placed just behind the head, and being generally much larger than the latter. Each paddle (fig. 565, 4) is composed of numerous 216 EXTIN CT ORDERS OF REPTILES. short polygonal bones, arranged in generally five longitudinal and closely-approximated rows, the apparent number of the digits being increased by the development of supernumerary rows of “marginal” ossicles on both sides of the paddle. Fig. 565.— a, Pectoral arch and fore-limbs of Ichthyosawrus: a, Interclavicle; b, b, Clavicles; c, c, Scapule; d, d, Coracoids ; e, Humerus; f, Radius; g, Ulna. (Somewhat altered from Huxley.) 8, Pelvis of Ichthyosaurus: p, Pubis; il, Uium ; is, Ischium, As regards their distribution in time, the Ichthyosaurs, as before said, are not known with certainty to have existed in rocks earlier than the Lias or later than the Chalk; and though abundant in the European area, no unequivocal re- mains of the genus have yet been detected in the corre- sponding formations in North America.! In the year 1861, however, Professor Marsh discovered in the Coal-measures of Nova Scotia two large amphiccelous vertebrae, which he de- scribed under the name of Hosawrus Acadiensis. These ver- tebre (fig. 566) are of very large size (about two and a half inches in diameter), and they are deeply excavated at both ends. They are regarded by Professor Marsh as indicating ' Since these sheets have been in the hands of the printer, Professor Marsh has described the remains of a large Saurian from the Jurassic rocks of the Rocky Mountains, which agrees with Jchthyosawrus in the general structure of the skeleton, but in which there are no teeth. The length of this singular Reptile is about eight or nine feet, the vertebrae are deeply biconcave, there are eight sclerotic plates, and the orbits are very large. It has been named Sauranodon natans, and Professor Marsh regards it as the type of a new order of Reptiles (Sawranodonta). EXTINCT ORDERS OF REPTILES. Dl the existence in the later Carboniferous period of a gigantic reptile allied to Lchthyosaurus. If this view were confirmed, it would carry back the range of the Ichthyosaurs to the Carboniferous ; but it is believed by Huxley that these re- mains may truly belong to some large Labyrinthodont. Fig. 566.—Two vertebre of Eosawrus Acadiensis (Marsh). Coal-measures of Nova Scotia. (After Dawson.) As regards their habits, there is no doubt whatever but that the Jchthyosaurt were essentially marine animals, and they have been often included with the next order (Sawro- pterygia) in a common group, under the name of Hnaliosawria or Sea-lizards. In the biconcave vertebrae and probable presence of a ver- tical tail-fin, the Jchthyosauwrus approaches the true Fishes. There is, however, no doubt as to the fact that the animal was strictly an air-breather, and its reptilian characters can- not be questioned, at the same time that the conformation of the limbs is decidedly Cetacean in many respects. Much has been gathered from various sources as to the habits of the Ichthyosaurus, and its history is one of great interest. From the researches of Buckland, Conybeare, and Owen, the fol- lowing facts appear to be pretty well established: That the Ichthyosaurt kept chiefly to open waters may be inferred from their strong and well-developed swimming-apparatus. That they occasionally had recourse to the shore, and crawled 218 EXTINCT ORDERS OF REPTILES. upon the beach, may be safely concluded from the presence of a strong and well-developed bony arch, supporting the fore- limbs, and closely resembling in structure the scapular arch of the Ornithorhynchus or Duck-mole of Austraha. That they lived in stormy seas, or were in the habit of diving to con- siderable depths, is shown by the presence of a ring of bony plates in the sclerotic, protecting the eye from injury or pres- sure. That they possessed extraordinary powers of vision, especially in the dusk, is certain from the size of the pupil, and from the enormous width of the orbits. That they were carnivorous and predatory in the highest degree is shown by the wide mouth, the long jaws, and the numerous, powerful, and pointed teeth. This is proved, also, by an examination of their petrified droppings, which are known to geologists as “ coprolites,” and which contain numerous fragments of the scales and bones of the Ganoid fishes which inhabited the same seas. Orper VI. SAUROPTERYGIA, Owen (= Plesiosauria, Hux- ley).—This order of extinct reptiles, of which the well-known Plesiosaurus ray be taken as the type, is characterised by the following peculiarities :— The body, as far as is known, was naked, and not furnished with any horny or bony exoskeleton. The bodies of the vertebra: were either flat or only slightly cupped at each end, and the neural arches were anchylosed with the centra, and did not remain distinct during life. The transverse processes of the vertebre were long, and the anterior trunk-ribs had simple, not bifurcate, heads. No sternum or sternal ribs are known to have existed, but there were false abdominal ribs. The neck (fig. 567) in most was greatly elongated, and composed of numerous vertebre. The sacrum was composed of two vertebre. The orbits were of large size, and there was a long snout, as in the Ichthyosauri, but there was no circle of bony plates in the sclerotic. The limbs agree with those of the Ichthyosaurt im being in the form of swimming-paddles (fig. 568), but daffer in not possessing any supernumerary marginal ossicles. The spec- toral arch consisted of a large coracoid and scapula on each side, while clavicles and an interclavicle were sometimes present, but at other times apparently wanting. The teeth were simple, EXTINCT ORDERS OF REPTILES. 219 and were inserted into distinct sockets, and not lodged in a common groove. The most familiar and typical member of the Sauropteryqia is the genus VPlesiosaurus (fig. 567), comprising gigantic Fig. 567.—Plesiosaurus dolichodeirus. Lias. marine reptiles, chiefly characteristic of the Lias and Oolites. In its general structure, there are various points in which Plesiosaurus makes a near approach to Jchthyosawrus, while, on the other hand, there are equally striking points of difference between the two genera. Thus, in both, the pelvic and pectoral limbs have the digits enveloped in the integument, and the fore-arm and arm much shortened, these organs thus being reduced to the condition of efficient swimming-paddles or “flippers.” In both the skin is naked, and the snout is prolonged, the jaws being furnished with numerous teeth. In both there is an absence of a sternum and of sternal ribs, but the walls of the abdomen are strengthened by supplementary ossifi- pu LN Seas cations, each consisting of a central and of paddle of Plesiosourus. lateral overlapping pieces. On the other ? yet?” Badin; hand, the head in Plesiosaurus is com- paratively small, and the neck is quite disproportionately elongated, while the tail is short. The orbits are not ex- 220 EXTINCT ORDERS OF REPTILES. ceptionally large, and though the nostrils are placed close beside the orbits, as in Jchthyosaurus, there is no sclerotic ring. The teeth are conical and pointed, with longitudinally striated crowns, but each is sunk in an independent socket. The vertebral centra are only slightly biconcave, and the neutral arches are united with them by osseous junction. The pectoral arch consists of a large coracoid and scapula on each side, but clavicles and interclavicle may be apparently wanting. The paddles are proportionately longer than those of Ichthyosaurus, and though formed on the same plan, consist only of the five digits, without marginal ossicles in addition. The pelvic arch is well developed, and there is a sacrum of two vertebre. As regards the habits of the Plesiosaurus, Dr Conybeare arrives at the following conclusions: “That it was aquatic is evident from the form of its paddles; that it was marine is almost equally so from the remains with which it is universally associated ; that it may have occasionally visited the shore, the resemblance of its extremities to those of the Turtles may lead us to conjecture; its movements, however, must have been very awkward on land; and its long neck must have impeded its progress through the water, presenting a striking contrast to the organisation which so admirably fits the Jchthyosawrus to cut through the waves.” As its respiratory organs were such that it must of necessity have required to obtain air frequently, we may conclude “that it swam upon or near the surface, arching back its long neck like a swan, and occasionally darting it down at the fish which happened to float within its reach. It may per- haps have lurked in shoal water along the coast, concealed amongst the sea-weed; and raising its nostrils to a level with the surface from a considerable depth, may have found a secure retreat from the assaults of powerful enemies ; while the length and flexibility of its neck may have compensated for the want of strength in its jaws, and its incapacity for swift motion through the water.” The geological range of the Plesiosawrus is from the Lias to the Chalk inclusive, and specimens have been found in- dicating a length of from eighteen to twenty feet. About twenty species of Plesiosaurus have been described in all. bo fe EXTINCT ORDERS OF REPTILES. 23 Of the remaining genera of the Sauwropterygia, Nothosaurus, Simosaurus, Placodus, Pistosaurus, and Conchiosaurus are Tri- assic. In Nothosawrus (fig. 569) the neck is long, and com- Fig. 569.—Skull of Nothosaurus mirabilis, reduced size. Trias (Muschelkalk), Germany. posed of at least twenty vertebre. The dorsal vertebre are biconcave, and the limbs are converted into swimming-pad- dles. The teeth are numerous and conical, and are implanted into distinct sockets. Several species are known, all Triassic, and especially characteristic of the Muschelkalk. Stimosawrus had a large head with enormous orbits, and teeth sunk into distinct sockets. This genus is exclusively confined to the Muschelkalk. In Placodus (fig. 570), the teeth are in dis- tinct sockets, and resemble those of many fishes in being rounded and obtuse, forming broad crushing plates adapted for the comminution of shell- fish. The upper jaw contains a double series of these teeth, an outer or maxillary series, and an internal or palatal series ; but the under jaw has only a single row of teeth. In the Jurassic period the Fis. 570.—Under surface of the upper jaw ; : G ; in Placodus gigas. Muschelkalk. principal genus is Pliosawrus, comprising huge reptiles, allied to the Plesiosawrus in their fin- like paddles, but having an enormous head supported upon a short neck. The teeth are simple and conical, and in large specimens attain a great size. Plioswwrus is confined to the Middle and Upper Oolites. Other Jurassic genera of Sawrop- terygia are known, but they present no features of special importance. In the Cretaceous period, lastly, the principal European representative of this order is Plesiosaurus itself ; whereas in deposits of corresponding age in North America, 222 EXTINCT ORDERS OF REPTILES. we meet with types such as Pliosawrus and the related genera Discosaurus (or Hlasmosaurus), and Cimoliosaurus. OrpER VII. ANomMoponTIA——The members of this order are especially characterised by the structure of the mouth, the jaws being converted into a kind of beak, which was probably sheathed im horn, and resembled the gaws of a Turtle. Some- times the mouth appears to have been wholly destitute of teeth, but in other cases there was a single pair of teeth invplanted in the wpper jaw, growing from persistent pulps, and assuming the character of great tusks. The dorsal vertebre are biconcave, and the anterior trunk-ribs have bifurcate heads. The sacrum is large, conposed of several vertebre. The animal seems to have been organised for terrestrial progression, the pectoral and pelvie arches being strong, and the limbs well developed. According to Prof. Huxley, the form of the body in the Anomodonts was probably like that of the Lizards; but the vertebrae are of a Crocodilian type, and though the skull exhibits Lacertilan characters, the jaws remind us more of the Chelonians. By Owen the genera Dicynodon, Oudenodon, and Rhyncho- saurus are included in this order; but the last of these is regarded by Huxley as a Lacertilian. In Dicynodon (fig. 571, A), the anterior portions of the jaws appear to have been altogether toothless; and they form a kind of beak, which was probably sheathed in horn. The lower jaw has no teeth; but each superior maxilla carries an enormous tusk-like tooth growing from a persistent pulp. These great canines pass downwards outside the forepart of the lower jaw, about one-third of their length being concealed within their sockets. In minute structure they consist of simple, compact, non-vascular dentine, with a thin layer of enamel ; and their points are simply conical and not bevelled or chisel- shaped. Probably they were used solely as weapons of offence and defence. In Oudenodon, on the other hand, the mouth is beak-shaped (fig. 571, B), and seems to have possessed no teeth of any kind. Dicynodon and Oudenodon are known only from strata of supposed Triassic age in India and South Africa. OrvdER VIII. Prerosaurta (Ornithosauria, Seeley).—This EXTINCT ORDERS OF REPTILES. TORS order includes a group of extraordinary flying Reptiles, all belonging to the Mesozoic epoch, and exhibiting in many respects a very extraordinary combination of characters. Fig. 571.—a, Skull of Dicynodon lacerticeps, showing the maxillary tusk; B, Skull of Oudenodon Bainit. From the Trias of South Africa, (After Owen.) The most familiar members of the order are the so-called “ Pterodactyles,” and the following are the characters of the order :— No exoskeleton 1s known to have existed. The dorsal vertebre are procelous, and the anterior trunk-ribs are double-headed. There is a broad sternum with a median ridge or keel, and ossified sternal ribs. The gaws were generally armed with teeth, and these were implanted in. distinct sockets. In some forms (Rhamphorhynchus) there appear to have been no teeth in the anterior portion of the jaws, and these parts seem to have been sheathed in horn, so as to constitute a kind of beak. In the genus Pteranodon, from the Cretaceous rocks of North America, comprising gigantic examples of the order, the jaws are completely destitute of teeth, and appear to have been encased in a horny beak. A ring of bony plates occurs in the sclerotic coat of the eye. 224 EXTINCT ORDERS OF REPTILES. The pectoral arch consists of a scapula and distinct coracoid bone, articulating with the sternum as in Birds, but no clavicles have hitherto been discovered. The fore-limb (fig. 572) consists of a humerus, ulna and radius, carpus, and hand of four fingers, of which the inner three are short and unguiculate, whilst the outermost is clawless and is enormously elongated. Between this immensely-lengthened finger, the side of the body, and the comparatively small hind-limb, there nvust have been supported an expanded flying - membrane, or “patagium,”’ which the aumal must have been able to employ as a wing, much as the Bats of the present day. Lastly, most of the bones were “pneu- matic” —that is to say, were hollow and filled with air. While the above are the general characters of the Ptero- swuria, there are various points in the anatomy of these Fig. 572.—Pterodactylus crassirostris. From the Lithographic Slates of Solenhofen (Upper (Oolite). In accordance with the view originally entertained, the digits of the hand are here erroneously represented as five instead of four in number. singular Reptiles which may be more closely considered. The head in all the Pterosaurs is elongated and_ bird-like, the cranial bones becoming early anchylosed, the general fabric of the skull being unusually light, and the orbits being exceptionally large. The occipital condyle is placed on the inferior aspect of the skull, instead of being posterior, thus indicating that the animal was in the habit of standing in an EXTINCT ORDERS OF REPTILES. 225 erect posture. The vertebral column is divisible into its usual regions, the cervical region being long, and composed of large and strong vertebre, which do not carry ribs. In the proccelous form of the dorsal vertebre, the Pterosaurs agree with many Reptiles, and differ from all known Birds. The sacrum consists of from three to six vertebre, and the tail is very short in Pterodactylus, and very long in Dimorphodon. It is, however, in the structure of the limbs and their sup- porting arches that the Pterosaurs exhibit some of their most remarkable characters. The pectoral arch is in many re- spects very ornithic in its character, with long and slender scapulee and distinct coracoids, but no clavicles are known. The sternum (fig. 573, B) is of large size and broad form, and resembles that of Birds in having a median ridge or keel. Ossified costal cartilages or “sternal ribs” connect the breast-bone with the ribs, as in Birds; but there is the Rep- tilian character that splint-like abdominal ribs are present. The brachium and antibrachium present no peculiarities of special note. The hand consists of four digits, of which, in accordance with the views generally entertained, the inner- most or thumb consists of two phalanges, the second or index has three phalanges, and the third or middle finger has four phalanges. All these three digits, also, are clawed. The fourth digit or ring-finger, on the other hand, is greatly elon- gated, and is clawless (figs. 573, 574). It carries the flying membrane, and consists usually of four phalanges, though it has only two phalanges in Ornithopterus. It should be men- tioned that this elongated digit is sometimes regarded as being really the index. As regards the hind-limb, the pelvis is very small; the ila are produced both in front of and behind the acetabu- lum, as in Birds; and the foot generally consists of five digits, of which four have sharp claws, while the “little toe” may either be rudimentary or longer than the other toes, serving in the latter case to assist in the expansion of the flying-membrane (fig. 574, p). According to Prof. Seeley, the lower end of the tibia is really formed by an- chylosis of the true tibia with the proximal tarsal bone, as in Birds. VOL. II. P 226 EXTINCT ORDERS OF REPTILES. With regard to the affinities of the Pterosawria, and their precise systematic position, scientific opinion is still not ab- Fig. 573.—a, Fore-limb of Pterodactylus Fig. 574. — Skeleton of Dimorphodon crassirostris: h, Humerus ; 7, Radius ; wu, macronyx, reduced in size and restored Ulna; c, Carpus ; i, ii, iii, iv, Digits. B, (after Owen). m, Hand; f, Elongated Sternum of Pterodactyle, showing the finger carrying the patagium; p, Foot. median keel. Lias. solutely unanimous. That they possessed the power of true EXTINCT ORDERS OF REPTILES. Qi, flight 1s conclusively shown by the presence of a median keel upon the sternum, proving the existence of unusually- developed pectoral muscles; by the articulation of the cora- coid bones with the top of the sternum, providing a fixed point or fulcrum for the action of the pectoral muscles ; and, lastly, by the existence of air-cavities in the bones, this being a feature otherwise peculiar to the true Birds. The apparatus, however, of flight was not a “wing,” as in Birds, but a flying-membrane, very similar in its mode of action to the patagium of the Mammalian order of the Bats. The patagium of the Bats, however, differs from that of the Pterodactyles in being supported by the greatly-elongated fingers, whereas in the latter it is only the outermost finger which is thus lengthened out. Moreover, to mention one other point of difference only, the Pterodactyles possess pneumatic foramina in some of the bones, indicating a structure of the breathing-organs similar to that now found in the Birds, and wholly unknown amongst the Mammals. The only question, then, at the present day is as to whether the Pterosaurs are most nearly related to the Reptiles or to the Birds ; and it is amongst the former that they are most generally placed. No known Reptile has any power of sus- taining itself in the air in any manner which can justifiably be compared with the flight of Birds; since the little Fly- ing Dragons (Draco) simply take leaps from tree to tree by means of laterally-extended folds of skin. No known Reptile, further, has pneumatic bones; and there are other points of difference which separate the Pterosaurs from all the typi- cal Reptiles. Still, the general structure of the skeleton is distinctly Reptilian; and the absence of a non-conducting covering of feathers to the skin would prove that the ani- mal must have been cold-blooded. The structure of the hand, further, though abnormal, is exceedingly unlike that which obtains in Birds. Lastly, it is only in certain very aberrant Cretaceous Birds that we meet with teeth in the jaws. These considerations would seem to justify the ref- erence of the Pterosawria to the Reptilia, of which they form an altogether peculiar order. Prof. Seeley, however, regards the Pterosaurs as forming a distinct class which he 228 EXTINCT ORDERS OF REPTILES. terms Ornithosauria, and which he looks upon as most nearly related to, but coequal with, the class Aves. The chief grounds for this conclusion, apart from subordinate skeletal peculiarities, are that the Pterosaurs possessed a brain of an ornithic type of structure, and that some of their bones were pneumatic. The Pterosauria are exclusively Mesozoic, being found from the Lower Lias to the Middle Chalk inclusive, the Litho- graphic Slate of Solenhofen (Upper Oolite) being particularly rich in their remains. Most of them appear to have attained no very great size, but the remains of forms from the Cre- taceous rocks have been considered to indicate animals with more than twenty feet expanse of wing, counting from tip to tip. The chief generic types of the Pterosauria are charac- terised as follows :— 1. Pterodactylus (fig. 572), comprising forms with four phalanges in the wing-finger, the jaws provided with teeth to their extremities, and all the teeth being long and slender. The tail is short and movable. Fig. 575.—Restoration of Dimorphadon macronyx. (After Owen.) 2. Dimorphodon (figs. 574 and 575), comprising forms in which the wing-finger has four phalanges, and the jaws EXTINCT ORDERS OF REPTILES. 229 are toothed; but the anterior teeth are large and pointed, and the posterior teeth are small and lancet-shaped. The tail is extremely long and movable. This genus is only known to occur in the Lias. 3. Rhamphorhynchus, comprising forms in which there are four joints to the wing-finger ; but the front portion of both jaws is edentulous, and may have formed a horny beak, teeth being developed only in the hinder portion of the jaws. The tail is very long. The genus seems to be confined to the Jurassic rocks. 4. Pteranodon, comprising forms which appear to have the general structure of Pterodactylus, but the jaws are wholly destitute of teeth, and were probably ensheathed in horn. The scapulee and coracoids are anchylosed, and the proximal ends of the scapulee apparently show the unique character of being articulated to the neural spine of one of the dorsal vertebree. The tail is short and slender. Myctisawrus resembles the preceding in having edentulous jaws, but the scapula is not anchylosed with the coracoid, nor articulated with a vertebra. These two genera comprise gigantic forms of Péero- sauria from the Cretaceous deposits of North America; and Prof. Marsh, to whom we owe a knowledge of their charac- ters, regards them as forming a distinct section (Pleranodontia) of the order. 5. Ornithopterus, comprising forms in which the wing- finger has only two phalanges. This genus is only imperfectly known, and may possibly be really referable to the Birds. OrvEeR IX. Derosaurta (Ornithoscelida, Huxley). — The next order of the Reptiles is that of the Deimosawria, com- prising a group of very remarkable extinct forms, which are in some respects intermediate in their characters between the Cursorial birds and the typical Reptiles; whilst they have been supposed to have affinities to the Pachydermatous Mam- mals. Most of the Deinosauria were of gigantic size, and the order is defined by the following characters :— The skin was sometimes naked, sometumes furnished with a well-developed exoskeleton, consisting of bony shields, much re- sembling those of the Crocodiles. A few of the anterior verte- bre were opisthocelous, the remainder having flat or slightly 230 EXTINCT ORDERS OF REPTILES. biconcave bodies. The anterior trunk-ribs were double-headed. The teeth were confined to the yaws and implanted in distinct sockets. There were always two pairs of limbs, and these were strong, furnished with claws, and adapted for terrestrial pro- gression. In some cases the fore-limbs were very small in pro- portion to the size of the hind-limbs. No clavicles have been discovered. The teeth are sometimes implanted in distinct sockets, and they are never anchylosed with the jaws. The ischium and pubes are much elongated; the inner wall of the acetabulum is formed by membrane; the tibia has its proximal end prolonged anteriorly into a strong “cnemial crest,’ as in the wading or swimming birds; and the astragalus is bird-lke (Huxley). The most remarkable points in the organisation of the Deinosauria are connected with the structure of the pel- vis and hind-limb, the charac- ters of which, as pointed out by Huxley, approximate to those of the same parts in the Birds, and especially in the Struthious Birds. This ap- proximation is especially seen in the prolongation of the ium in front of the acetabu- lum (fig. 576), the elongation and slenderness of form of the ischium, and the slender- iy Ischimy f,Femur; 4 Tibia; s,'Fibulay CSS of the pubes. The as- as, Astragalus; oa, Caleaneum; m, Meta- tpagalus is like that of a bird tarsus. (After Huxley.) = : } and in some cases appears to have become anchylosed with the distal end of the tibia. Generally, however, the astragalus remains distinct, but even in this case the ankle-joint is placed between the astragalus and the distal portion of the tarsus. The metatarsal bones EXTINCT ORDERS OF REPTILES. 231 also remain distinct, and are not anchylosed with any of the tarsal bones to form a “ tarso-metatarsus.” The Deinosawria are exclusively Mesozoic, ranging from the Triassic to the Cretaceous formation, but abounding especially in the Oolitic and the earlier portion of the Cre- taceous period. By Professor Huxley the “Thecodont ” Reptiles are regarded as belonging here, as has been already remarked. The number of known Deinosaurian Reptiles is already extremely large, but as many are only very imperfectly understood, it will be sufficient here to briefly notice a few of the more important or more interesting types. The number of genera known in the Trias (such as Teratosaurus, Amphi- saurus, Clepsysaurus, Bathygnathus, &c.) is not very large, but even at this early period the order seems to have had a very wide distribution. In the Jurassic and Cretaceous periods the order under- went an immense development, and is represented by numer- ous genera, such as Iguanodon, Hypsilophodon, Laosaurus, Hadrosaurus, Cionodon, Porkilopleuron, Hyleosaurus, Pola- canthus, Acanthopholis, Cetiosaurus, Titanosaurus, Megalosaurus, Lelaps, Compsognathus, Chondrosteosaurus, &e. Of the above the most important types are Jguanodon, Hylowosaurus, Me- galosaurus, Cetiosaurus, Compsognathus, and Chondrosteosaurus. The Zguanodon is mainly, but not exclusively, Cretaceous, being especially characteristic of the great delta-deposit of the Wealden. The length of the Jywanodon has been esti- mated as being probably from fifty to sixty feet, and from the close resemblance of its teeth to those of the living Iguanas, there is little doubt that it was herbivorous and not carnivorous. The femur of a large Jguwanodon measures from four to five feet in length, with a circumference of twenty- two inches in its smallest part. From the disproportionately small size of the fore-limbs, and from the occurrence of pazrs of gigantic three-toed footsteps in the same beds, it has been concluded, with much probability, that Jguanodon, in spite of its enormous bulk, must have walked temporarily or per- manently upon its hind-legs, thus coming to present a most marked and striking affinity to the Birds. 232 EXTINCT ORDERS OF REPTILES. The teeth of Jgwanodon (fig. 577) present a singularly close resemblance in shape to those of the comparatively pigmy Iguanas of the present day. Their crown is obtusely sub- triangular, with longitudinal ridges, and having the surface Fig. 577.—Teeth of Iyuanodon Mantelliit. Wealden. of the enamel crenated on one or both sides. They present the extraordinary feature that the crown became worn down flat by mastication, showing that Zguwanodon employed the teeth in the actual trituration of the vegetable matter on which it fed. The front portion of the jaws seems to have been toothless and beak-like, and the symphysis of the man- dible is hollowed out above; the purpose served by this, according to the views of Professor Owen, being to facilitate the easy protrusion and retraction of a long muscular and prehensile tongue, employed by the animal in stripping off the foliage of trees. In the Cretaceous deposits of North America the genus Jguwanodon is represented by the nearly- alhed Hadrosaurus. Iguanodon is not known to have pos- sessed any exoskeletal structures capable of preservation in the fossil state; but the Hylwosaurus of the Wealden pos- sessed bony dermal scutes, prolonged along the middle line of the back into a row of enormous spines. The gigantic Cetiosaurus of the Oolitic and Cretaceous rocks was originally placed amongst the Crocodilia ; but the EXTINCT ORDERS OF REPTILES. 233 researches of Professor Phillips have shown that it belongs really to the Deinosauria. Having obtained a magnificent series of remains of this reptile, Professor Phillips has been able to determine many very interesting points as to the anatomy and habits of this colossal animal, the total length of which he estimates as being probably not less than sixty or seventy feet. As to its mode of life, this accomplished writer remarks :—. “ Probably when ‘standing at ease’ not less than ten feet in height, and of a bulk in proportion, this creature was un- matched in magnitude and physical strength by any of the largest inhabitants of the Mesozoic land or sea. Did it live in the sea, in fresh waters, or on the land? This question cannot be answered, as in the case of Ichthyosaurus, by appeal to the accompanying organic remains; for some of the bones le in marine deposits, others in situations marked by estuarine conditions, and, out of the Oxfordshire district, in Sussex, in fluviatile accumulations. Was it fitted to live exclusively in water? Such an idea was at one time enter- tained, in consequence of the biconcave character of the caudal vertebree, and it is often suggested by the mere magni- tude of the creature, which would seem to have an easier life while floating in water, than when painfully lifting its, huge bulk, and moving with slow steps along the ground. But neither of these arguments is valid. The ancient earth was trodden by larger quadrupeds than our elephant; and the biconcave character of vertebrae, which is not uniform along the column in Cetiosaurus, is perhaps as much a character of a geological period as of a mechanical function of life. Good evidence of continual life in water is yielded in the case of Ichthyosaurus, and other Enaliosaurs, by the articu- lating surfaces of their limb-bones, for these, all of them, to the last phalanx, have that slight and indefinite adjustment of the bones, with much intervening cartilage, which fits the leg to be both a flexible and forcible instrument of natation, much superior to the ordinary oar-blade of the boatman. On the contrary, in Cetiosaur, as well as in Megalosaur and Ieuanodon, all the articulations are definite, and made so as to correspond to determinate movements in particular direc- 234 EXTINCT ORDERS OF REPTILES. tions, and these are such as to be suited for walking. In particular, the femur, by its head projecting freely from the acetabulum, seems to claim a movement of free stepping more parallel to the line of the body, and more approaching to the vertical than the sprawling gait of the crocodile. The large claws concur in this indication of terrestrial habits. But, on the other hand, these characters are not contrary to the belief that the animal may have been amphibious; and the great vertical height of the anterior part of the tail seems to support this explanation, but it does not go further. For the later caudal vertebrae, instead of being much compressed, as in Teleosaurus, are nearly circular in the cross section, and are interlocked by posterior zygapophyses, extended over half or the whole length of a vertebrae. We have therefore a marsbh-loving or river-side animal, dwelling amidst filicine, cycadaceous, and coniferous shrubs and trees full of insects and small mammalia. What was its usual diet? If ex ungue leonem, surely ex dente cibum. We have indeed but one tooth, and that small and incomplete. It resembles more the tooth of Iguanodon than that of any other reptile ; and for this reason it seems probable that the animal was nourished by similar vegetable food which abounded in the vicinity, and was not obliged to contend with Megalosaurus for a scanty supply of more stimulating diet.” Colossal as are the dimensions of Cetioswuwrus, they appear to have been exceeded by species of the genus Atlantosaurus (Titanosaurus). Thus A. montanus, from the Wealden of Colorado, according to Prof. Marsh, “is by far the largest land-animal yet discovered; its dimensions being greater than was supposed possible in an animal that lived and moved upon the land. It was some fifty or sixty feet in length, and, when erect, at least thirty feet in height. It doubtless fed upon the foliage of the mountain forests, por- tions of which are preserved with its remains.” Megalosaurus is a gigantic Oolitic Reptile, which occurs also in the Cretaceous series (Weald Clay). Its length has been estimated at between forty and fifty feet, the femur and tibia each measuring about three feet in length. As the head of the femur is set on nearly at right angles with the EXTINCT ORDERS OF REPTILES. 23) shaft, whilst all the long bones contain large medullary cavities, there can be no doubt but that Megalosaurus was terrestrial in its habits. That it was carnivorous and de- structive in the highest degree is shown by the powerful, pointed, and trenchant teeth. The teeth in Megalosaurus (fig. 578) are conical, com- pressed, with finely-serrated edges. The fore-limbs are ex- Fig. 578.—Cranium of Megalosaurus, restored. (After Professor Phillips.) traordinarily smaller than the hind-limbs. The teeth do not become worn by mastication; and there appears to have been no exoskeleton. In the Cretaceous deposits of North America the place of MMegalosaurus is taken by the closely - allied Lelaps (or Dryptosaurus). One of the most remarkable of the Deinosawria is the little Compsognathus longipes of the Lithographic Slate of Solen- hofen, regarded by Professor Huxley as the type of a special group (Compsognatha) of his order Ornithoscelida. The special characters distinguishing this group are, that the cervical region of the spine is long, and the femur is shorter than the tibia; whereas in the typical Deinosauria the neck is rela- tively short, and the femur is as long as, or longer than, the tibia. Compsognathus is not remarkable for its size, which does not seem to have been much more than two feet, but for the striking affinities which it exhibits to the true Birds. The head of Compsognathus was furnished with toothed jaws, and supported upon a long and slender neck. The fore- 236 EXTINCT ORDERS OF REPTILES. limbs were very short, but the hind-limbs were long and like those of Birds. The proximal portion of the tarsus resembled that of Birds in being anchylosed to the lower end of the tibia; but the distal portion of the tarsus—unlike that of Birds—was free, and was not anchylosed with the meta- tarsus. Huxley concludes that “it is impossible to look at the conformation of this strange Reptile, and to doubt that it hopped or walked in an erect or semi-erect position, after the manner of a bird, to which its long neck, slight head, and small anterior limbs must have given it an extraordinary resemblance.” The last type of the Deinosawria which we shall notice here is the singular genus Chondrosteosaurus (= Camaro- swurus), comprising gigantic reptiles from the Cretaceous formations of Britain and North America. The size reached by some of the species of this genus was enormous, the length probably being sixty or seventy feet, while the mas- sive construction of the skeleton is as remarkable as its mere linear extension. Thus, in an American species, the first cervical vertebra is “twenty inches in length and twelve in transverse diameter, and one of the dorsals measures three and a half feet in the spread of its diapophyses, two and a half feet in elevation, with the centrum thirteen inches in diameter” (Cope). The femur was six feet in length, and the scapula five and a half feet; while the neck was pro- bably ten feet long. The vertebre (fig. 579) are opistho- ccelous, and the centra are hollowed out into large lateral sinuses on each side, which are believed by Owen to have been filled with unossified cartilage, but which Cope looks upon as possibly having contained air. The trunk-ribs are connected with the vertebree by double articulation, as in the Crocodiles. The neural arches of the vertebra are im- mensely elevated (fig. 579), and the sides of the centra are excavated by depressions, which are conjectured by Owen to have lodged saccular processes of the lung, and which Cope beleves to have communicated by open foramina with the internal sinuses of the vertebral body. From the immense size of the scapula and humerus, and the proportionately small size of the pelvis, it may be safely inferred that these EXTINCT ORDERS OF REPTILES. Dou enormous reptiles walked upon all-fours; and it seems not unlikely that their habit of existence was really a semi- Fig. 579 —Anterior dorsal vertebra of Chondrosteosaurus (Camarosaurus) supremus, reduced in size and viewed from behind. (After Cope.) Cretaceous, North America. aquatic one. The Amphicelias of the Cretaceous of North America is nearly alhed to Chondrosteosaurus, and the Dystro- pheus of the Trias of Utah seems to have belonged to the same group. It would seem that the genera just mentioned belong to the same natural group of the Deinosaurs as those which Marsh has recently raised to the rank of a sub-order under the name of Sawropoda. The genera in question (Atlanto- saurus, Morosaurus, &c.) are from the Jurassic rocks of America, and are characterised by the nearly equal size of the fore and hind limbs, the feet bemg pentadactylous and plantigrade, and the limb-bones without medullary cavities. The carpal and tarsal bones are distinct; the pubes unite in front by a ventral symphysis; the preecaudal vertebrae con- tain large cavities, possibly pneumatic ; and the neural arches are united to the centra by suture. 238 EXTINCT ORDERS OF REPTILES. Finally, it may just be mentioned that the remains of Deinosaurs (¢.g., Agathawmas) are found in the so-called “ Lignitic Series” of North America, which some high authorities regard as being really of early Tertiary age. The evidence available at present is, however, decidedly in favour of the view that these deposits truly belong to the closing portion of the Cretaceous period. OrpgR X. THERIODONTIA——This order has been founded by Professor Owen for the reception of a number of carnivor- ous Reptiles from deposits of Triassic or Permian age. The reptiles in question show some singular Mammalian affini- ties, especially to the Beasts of Prey. The dentition ws of the carnivorous type, the teeth being in three distinct sets—viz., incisors, canines, and molars, and the canines being large and pointed. In Cynodraco, which may be regarded as the best known form of the group, the canines are not only of immense size, Fig. 580.—a, Front view of the skull of Lycosawrus, showing the dentition ; B, Front view of the jaws of Cynodraco serridens, showing the incisor teeth; c, Side view of the jaws of Lyco- saurus, showing the incisors and the laniariform canines. c¢, Canines. (After Owen.) but are compressed in shape, and have the hinder trenchant border of the tooth minutely serrated, thus somewhat resem- bling the canines of the Sabre-toothed Tiger (Machairodus). The humerus is, further, furnished with a “supra-condyloid foramen” (similar to that of the humerus of the Felide) LITERATURE. 239 for the protection of the median nerve and brachial artery on their way down the arm. The genus Cynodraco (fig. 580, B) is only known as occurring in deposits believed to be of the age of the Trias in South Africa; and the same formation contains a large number of other Reptilian types which are referred by Prof. Owen to the order of the Theriodontia. The most important of these are Lyco- saurus (fig. 580, A and Cc), Cynochampsa, Galesaurus, Tigri- suchus, and Cynosuchus. The eminent paleontologist just mentioned has further indicated that certain Permian Rep- tiles (Brithopus, Deuterosaurus, &c.) are probably really refer- able to the Theriodonts; and it would seem probable that the Clepsydrops of Cope, from the Permian rocks of North America, should be regarded as a member of this order. LITERATURE. 1. ‘“ Ossemens fossiles.” Cuvier. 1836. 2. ‘Comparative Anatomy and Physiology of Vertebrate Animals.” Owen. 1866-68. 3. “ Manual of Paleontology.” Owen. 2ded. 1861. 4, “Traité de Paléontologie.” Pictet. 1853-57. 5. “A Manual of the Anatomy of Vertebrated Animals.” Huxley. 1872. 6. “ Bridgewater Treatise.” Buckland. 4th ed. 1869. 7. ‘“ Monograph on the Fossil Reptilia of the London Clay.” Part i., Chelonia. Owen and Bell. ‘ Palaeontographical Society.’ 1849. Part ii., Crocodilia and Ophidia. Owen. Jbid. 1850. 8. “Monograph of the Fossil Reptilia of the Cretaceous and Purbeck Strata.” Owen. Ibid. 1860. 9. “ Monograph on the Fossil Reptilia of the Wealden Formation.” Owen. Ibid. 1853, 1854, 1856, 1857, 1859, and Supplements extending to 1876. 10. “ Monograph on the British Fossil Reptilia of the Oolitic Forma- tions.” Owen. Ibid. 1861. 11. “ Monograph on the Fossil Reptiles of the Cretaceous Formation.” Owen. IJtid. 1851, 1864. 12. “ Monograph of the Fossil Chelonian Reptiles of the Wealden Clays and Purbeck Limestones.” Owen. Ibid. 1853. 13. “Monograph of the Fossil Reptilia of the Liassic Formations.” Owen. Ibid. 1865 and 1870. 14. “Monograph of the British Fossil Reptilia of the Kimmeridge Clay.” Owen. Ibid. 1869. 240 LITERATURE. . “Monograph of the British Mesozoic Reptilia.” Owen. Ibid. 1873, 1875, and 1877. . “Odontography.” Owen. 1840-45. . “Report on Fossil Reptiles.” Owen. ‘Brit. Assoc. Reports.’ 1841. - “On Dicynodon.” Owen. ‘Trans. Geol. Soc.’ 1845. . “Descriptive Catalogue of the Fossil Reptilia and Fishes in the Museum of the Royal College of Surgeons of England.” Owen. . “Catalogue of the Fossil Reptiles of South Africa in the Collec- tions of the British Museum.” Owen. 1876. . “On some Reptilian Fossils from South Africa.” Owen. ‘Quart. Journ. Geol. Soc.,’ vol. xvi. 1860. “On a Carnivorous Reptile (Cynodraco major),” &c. Owen. ‘Quart. Journ. Geol. Soc.’ 1876. . “On Evidences of Theriodonts in Permian Deposits.” Owen. ‘Quart. Journ. Geol. Soc.’ 1876. . “On the Stagonolepis Robertsoni.”. Huxley. ‘Quart. Journ. Geol. Soe” 1859. 5. “ On anew Specimen of Telerpeton Elginense.” Huxley. ‘Quart. Journ. Geol. Soc.’ 1866. . “On Hyperodapedon.” Huxley. ‘Quart. Journ. Geol. Soc.’ 1869. . “On the Affinities between the Dinosaurian Reptiles and Birds.” Huxley. ‘Quart. Journ. Geol. Soc.’ 1870. . “On the Classification of the Dinosauria,” &. Huxley, ‘Quart. Journ. Geol. Soc.’ 1870. . “On Vertebrate Fossils from the Panchet Rocks.” Huxley. ‘ Pal- eeontologia Indica.’ 1865. . “ The Ornithosauria.” Seeley. 1870. . “Index to the Fossil Remains of Aves, Ornithosauria, and Reptilia in the Woodwardian Museum.” Seeley. 1869. 2. “ Additional Evidence of the Structure of the Head in Pterosauria.” Seeley. ‘Ann. and Mag. Nat. Hist.,’ ser. 4, vol. vii. 1871. 33. “ Saurier des Muschelkalkes.” Von Meyer. 1847-55. . “Saurier aus dem Kupfer-Schiefer der Zechstein - formation.” Von Meyer. . “ Beitriige zur niheren Kenntniss fossilen Reptilien.” Von Meyer. ‘Leonhard and Bronn’s Neues Jahrbuch.’ 1857. . “Geology of Oxford and the Thames Valley.” Phillips. 1871. . “Structure of the Skull and Limbs in Mosasauroid Reptiles.” Marsh. ‘Amer. Journ. Sci. and Arts.” 1872. . “Cretaceous Reptiles of the United States.” Leidy. ‘Smith- sonian Contributions to Knowledge,’ vol. xiv. . “Contributions to the Extinct Vertebrate Fauna of the Western Territories.” Leidy. ‘Reports of the U.S. Geol. Survey of the Territories,’ vol. i. 1873. 40. 41. LITERATURE. 241 “The Vertebrata of the Cretaceous Formations of the West.” Cope. Jbid., vol. ii, 1875. “On Saurians recently discovered in the Dakota Beds of Colorado.” Cope. ‘ American Naturalist.’ 1878. . “ Homologies of some of the Cranial Bones of the Reptilia, and on the Systematic Arrangement of the Class.” Cope. ‘Amer. Assoc. for the Advancement of Science.” 1870, 3. “On the Rank and Affinities of the Reptilian Class of the Mosa- sauride.” Owen. ‘Quart. Journ. Geol. Soe.’ vol. xxxiil. 1877. VOL ue Q bo ra bo CHAPTER XXXVI BIRDS. Tue fourth class of the Vertebrata is that of Aves, or Birds. The Birds may be shortly defined as being “ oviparous Vertebrates with warm blood, a double circulation, and a covering of feathers” (Owen). More minutely, however, the Birds are defined by the possession of the following characters :— The skull articulates with the vertebral column by a single occipital condyle. The form of the vertebral centra varies ; but they are wm no case amphicelous, except in the extinet Ichthyornis. Each half or ramus of the lower jaw consists of a number of pieces, which are separate from one another in the embryo ; and the jaw is united with the skull, not directly, but by the intervention of a quadrate bone (as in the Reptiles). The fore-limb in no existing birds possesses more than three Singers or digits, and the metacarpal bones are anchylosed to- gether. In all living Birds the fore-limbs are useless as re- gards prehension, and in most they are organs of flight. The hind-limbs in all Birds have the ankle-joint placed im the middle of the tarsus, the proximal portion of the tarsus coalesc- ing with the tibia, and the distal portion of the tarsus being anchylosed with the metatarsus to constitute a single bone known as the “ tarso-metatarsus,” The heart consists of four chambers, two auricles and two ventricles ; and not only are the right and left sides of the heart completely separated from one another, but there is no BIRDS. 2438 communication between the pulmonary and systemic circula- tions, as there is in Reptiles. The respiratory organs are in the form of spongy cellular lungs, which are not freely suspended in pleural sacs; and the bronchi open on their surface into a number of air-sacs, placed in different parts of the body. All birds are oviparous, none bringing forth their young alive, or being even ovo-viviparous. All birds are, lastly, pro- vided with an epidermic covering, so modified as to constitute what are known as feathers. The entire skeleton of the Birds is singularly compact, and at the same time singularly light. The compactness is due to the presence of an unusual amount of phosphate of lime ; and the lightness, to the absence in many of the bones of the ordinary marrow, and its replacement by air. As regards the vertebral column, Birds exhibit some very interesting peculiarities. The cervical region of the spine is unusually long and flexible, since the fore-limbs are useless as organs of prehension—and all acts of grasping must be exercised either by the beak or by the hind-feet, or by both acting in conjunction. The number of vertebre in the neck varies from eight to twenty-three. The front faces of their centra are cylindroidal (spheroidal in Penguins), convex from above downwards, and concave from side to side, the posterior faces being concave from above downwards and convex from side to side. Hence in vertical section, the vertebre appear to be opisthocelous, and in horizontal section procelous. This structure of the cervical vertebra is highly characteristic of Birds. The dorsal vertebra vary from six to ten in number, and of these the anterior four or five are generally anchy- losed with one another, so as to give a base of resistance to the wings. In the Cursorial Birds, however (such as the Ostrich and Emeu), and in some others (such as the Pen- euin), in which the power of flight is wanting, the dorsal vertebree are all more or less freely movable one upon an- other. There are no lumbar vertebre, but all the vertebree between the last dorsal and the first caudal (varying from nine to twenty) are anchylosed together to form a bone which is ordinarily known as the “sacrum.” To this, in 244 BIRDS, turn, the iliac bones are anchylosed along their whole length, giving perfect immobility to this region of the spine and to the pelvis. The coccygeal or caudal vertebree vary in number from eight to ten, and are movable upon one another. In reality, however, the number of caudal vertebree is much greater than the above, since some of the vertebree of the anchylosed “ sacrum ” properly fall to be counted in this region, and the “ ploughshare-bone ” consists of more than one vertebra. The most noticeable feature about this part of the spinal column is what is known as the “ploughshare-bone.” This is the last joint of the tail, and is a long, slender, plough- share-shaped bone, destitute of lateral processes, and without any medullary canal (fig. 584, B). In reality it consists of two or more of the caudal vertebrae, completely anchylosed, and fused into a single mass. It is usually set on to the extremity of the spine at an angle more or less nearly per- pendicular to the axis of the body; and it affords a firm basis for the support of the great quill-feathers of the tail (“rectrices ”). In the Cursorial Birds, which do not fly, the terminal joint of the tail is not ploughshare-shaped. In the extraordinary Mesozoic bird, the Archwopteryx macrura, there is no ploughshare-bone, and the tail consists of twenty separate vertebrae, all distinct from one another, and each carrying a pair of quill-feathers, one on each side. As the vertebree of the ploughshare-bone are distinct from one another in the embryos of existing birds, the tail of the Archeopteryx is to be regarded as a case of the permanent retention in the adult of an embryonic character. In the increased number of caudal vertebrae, however, and in some other characters, the tail of the Archwopteryx makes a de- cided approach to that of the true Reptiles. The various bones which compose the skull of Birds are amalgamated in the adult so as to form a single piece, and the sutures even are obliterated, the lower jaw alone remain- ing movable. The occipital bone carries a single occipital condyle only, and this is hemispherical or nearly globular in shape. The “beak” (fig. 581), which forms such a conspic- uous feature in all birds, consists of an upper and lower half, BIRDS. 245 or a “superior” and “inferior mandible.’ The upper man- dible is composed almost entirely of the greatly-elongated intermaxillary bones, flanked by the comparatively small superior maxille. The inferior mandible is primitively com- Fig. 581.—Skull of Spur-winged Goose (Plectropterus Gambensis). posed of twelve pieces, six on each side; but in the adult these are all indistinguishably amalgamated with one another, _and the lower jaw forms a single piece. As in the Reptiles, the lower jaw articulates with the skull, not directly, but through the intervention of a distinct bone—the quadrate bone or tympanic bone—which always remains permanently movable, and is never anchylosed with the skull. In no living bird are teeth ever developed in either jaw, but both mandibles are encased in horn, forming the beak, and the margins of the bill are sometimes serrated. In the Tertiary Odontopteryx, however, the alveolar margins of the jaws are prolonged into tooth-like processes sheathed in the horny substance of the bill; and in the Cretaceous Odontornithes true teeth are present. The thoracic cavity is bounded behind by the dorsal ver- tebrae, which are usually, as before said, anchylosed with one another to a greater or less extent. Laterally, the thorax is bounded by the ribs, which vary in number from six to ten pairs. In most birds each rib carries a peculiar process —the “uncinate process”—which arises from its posterior margin, is directed upwards and backwards, and passes over the rib next in succession behind, where it is bound down by ligament. The first and last dorsal ribs carry no uncinate processes, and in some cases the processes continue through- 246 BIRDS. out life as separate pieces (fig. 582, B). Anteriorly, the ribs articulate with a series of straight bones, which are called the “sternal ribs,’ but which in reality are to be looked upon as the ossified “costal cartilages.” These sternal mbs (fig. 582, B) are in turn movably articulated to the sternum Fig. 582.—a, Breast-bone, shoulder-girdle, and fore-limb of Penguin (after Owen): 6, Sternum, with the sternal keel; s, s, Scapule ; k, k, Coracoid bones ; ¢, Furculum or merry- thought, composed of the united clavicles ; h, Humerus ; wu, Ulna; 7, Radius; ¢, Thumb ; m, Metacarpus ; p, Phalanges of the fingers. 3B, Ribs of the Golden Eagle: a, a, Ribs giving off (0, 6) uncinate processes ; ¢, c, Sternal ribs. in front, and “they are the centres upon which the respira- tory movements hinge” (Owen). In front the thoracic cavity is completed by an enormously-expanded sternum or breast-bone, which in some birds of great powers of flight extends over the abdominal cavity as well, in some cases even reaching the pelvis. The sternum of all birds which fly, is characterised by the presence of a greatly-developed median ridge or keel (fig. 582, a), to which are attached the ereat pectoral muscles which move the wings. As a general rule, the size of this sternal crest allows a very tolerable estimate to be formed of the flying powers of the bird to which it may have belonged; and in the Ostriches and other birds which do not fly, there is no sternal keel (fig. 583). BIRDS. 247 At its anterior angles the sternum exhibits two pits for the attachment of the coracoid bones. The scapular or pectoral arch consists of the shoulder-blade or scapula, the collar-bone or clavicle, and the coracoid bone, on each side. The scapula, as a rule (fig. 582, A, s,s) isa simple elongated bone, not flattened out into a broad plate, and carrying no transverse ridge, or spinous process. Only a portion of the glenoid cavity for the articulation with the head of the humerus is formed by the scap- ula, the remainder being formed by the coracoid. The coracoid bones (fig. 582, a, k, &) correspond with the coracoid processes of man, but in birds they are distinct bones, and are not anchylosed with the scap- ula. The coracoid bone on each side is always the strongest of the bones forming the scapular arch. Superiorly it articulates with the clavicle and scapula, and forms part of the glenoid cavity for the humerus. Inferiorly each coracoid bone articulates with the upper angle of the sternum. The position of the coracoids is more or less nearly vertical, so that they form fixed points for the action of the wings in their downward stroke. The clavicles (fig. 582, A, c) are rarely rudimentary or absent, and are in some few cases separate bones. In the great majority, however, of birds, the clavicles are anchylosed together at their anterior extremi- ties, so as to form a single bone, somewhat V-shaped, popu- larly known as the “merry-thought,” and technically called the “furculum.” The outer extremities of the furculum articulate with the scapula and coracoid ; and the anchylosed angle is commonly united by ligament to the top of the ster- num. The function of the clavicular or furcular arch is “to oppose the forces which tend to press the humeri inwards towards the mesial plane, during the downward stroke of the wing” (Owen). Consequently the clavicles are stronger, and their angle of union is more open, in proportion to the powers of flight possessed by each bird. Fig. 583.—Sternum of the Os- trich. s, Scapula; c, Coracoid. 248 BIRDS. As regards the structure of the wing proper, the humerus is short and strong, and articulates superiorly with an arti- cular cavity formed partly by the coracoid and partly by the scapula. The fore-arm is composed of a radius and ulna, of which the former is the smallest and most slender. The carpus is reduced to two small bones wedged in between the distal end of the fore-arm and the metacarpus. One other bone of the normal carpus (namely, the “os magnum”) is present, but this is anchylosed with one of the metacarpals. There are thus really three carpal bones, though only two appear to be present. (According to Morse, there is a fourth carpal, which early anchyloses with the base of the meta- carpal of the middle finger). The carpus is followed by the metacarpus, the condition of which agrees with that of the carpal bones. The two outermost of the normal five meta- carpals are absent, and the remaining three are anchylosed— together with the os magnum—so as to form a single bone (fig. 582, a, m). This bone, however, appears externally as if formed of ¢wo metacarpals united to one another at their extremities, but free in their median portion. The meta- carpal bone which corresponds to the radius is always the larger of the two (as being really composed of two meta- carpals), and it carries the digit which has the greatest num- ber of phalanges. This digit corresponds with the “index ” finger, and it is composed of two, or sometimes three, pha- langes. At the proximal end of this metacarpal, at its outer side, there is generally attached a single phalanx, constitut- ing the so-called “thumb,” which carries the “ bastard-wing,” and is sometimes furnished with a claw. The digit which is attached to the ulnar metacarpal corresponds to the middle finger, and never consists of more than a single phalanx. As regards the structure of the posterior extremity or hind- limb, the pieces which compose the innominate bones (namely, the ilium, ischium, and pubes) are always anchylosed with one another; and the two innominate bones are also always anchylosed, by the medium of the greatly-elongated ilia, with the sacral region of the spine. In no living bird, however, with the single exception of the Ostrich, are the innominate bones united in the middle line in front by a symphysis BIRDS. 249 pubis. The stability of the pelvic arch, necessary in animals which support the weight of the body on the hind-limbs alone, is amply secured in all ordinary cases by the anchy- losis of the ilia with the sacrum. As in the higher Vertebrates, the lower limb (fig. 584, A) consists of a femur, a tibia and fibula, a tarsus, metatarsus, and phalanges; but some of these parts are considerably obseured by anchylosis. The femur or thigh-bone (fig. 584, A, f) is generally very short, comparatively speaking. The chief bone of the leg is the tibia (¢), to which a thin and Fig. 584.—a, Hind-limb of the Loon (Colymbus glacialis)—after Owen : 7, Innominate bone ; f, Thigh-bone or femur; ¢, Tibia, with the proximal portion of the tarsus anchylosed to its lower end; 7, Fibula; m, Tarso-metatarsus, consisting of the distal portion of the tarsus anchylosed with the metatarsus ; p, p, Phalanges of the toes. B, Tail of the Golden Eagle : s, Ploughshare-bone, carrying the great tail-feathers. tapering fibula (7) is anchylosed. The upper end of the fibula, however, articulates with the external condyle of the femur. The ankle-joint is placed, as in Reptiles, between the proximal and distal portions of the tarsus. The proximal 250 BIRDS. portion of the tarsus, consisting of two bones representing the astragalus and calcaneum or the former only, is undis- tinguishably amalgamated with the lower end of the tibia. The distal portion of the tarsus is anchylosed with the second, third, and fourth metatarsals to constitute the most charac- teristic bone in the leg of the Bird—the “tarso-metatarsus ” (m). In most of the long-legged birds, such as the Waders, the disproportionate length of the leg is given by an extra- ordinary elongation of the tarso-metatarsus. The tarso-metatarsus is followed inferiorly by the digits of the foot. In most birds the foot consists of three toes directed forwards and one backwards—four toes in all. In no wild bird are there move than four toes, but often there are only three, and in the Ostrich the number is reduced to two. In all birds which have three anterior and one posterior toe, it is the posterior thumb or hallua (that is to say, the innermost digit of the hind-limb) which is directed back- wards; and it invariably consists of two phalanges only, its metatarsal being incomplete and united, as a rule, to the tarso- metatarsus by hgament only. The most internal of the three anterior toes (the “index ”) consists of three phalanges; the next (“middle”) has four phalanges; and the outermost toe (“annularis”) is made up of five phalanges (fig. 584, a). This increase in an arithmetical ratio of the phalanges of the toes, in proceeding from the inner to the outer side of the foot, obtains in almost all birds, and enables us readily to detect which digit is suppressed, when the normal four are not all present. Variations of different kinds exist, however, in the number and disposition of the toes. In many birds —such as the Parrots—the outermost toe is turned back- wards, so that there are two toes in front and two behind; whilst in the Trogons the inner toe is turned back with the hallux, and the outermost toe is turned forwards. In others, again, the outer toe is normally directed forwards, but can be turned backwards at the will of the animal. In the Swifts, on the other hand, all four toes are present, but they are all turned forwards. In many cases—especially amongst the Natatorial birds—the hallux is wholly wanting, or is rudi- mentary. In the Emeu, Cassowary, Bustards, and other BIRDS. 251 genera, the hallux is invariably absent, and the foot is three- toed. In the Ostrich both the hallux and the next toe (“index ”) are wanting, and the foot consists simply of two toes, these being the third and fourth digits. As regards the geological distribution of Birds, there are many reasons why we should be cautious in reasoning upon merely negative evidence, and more than ordinarily careful not to infer the non-existence of birds during any particular geological epoch, simply because we can find no positive evidence for their presence. As Sir Charles Lyell has well remarked, “the powers of flight possessed by most birds would insure them against perishing by numerous casualties to which quadrupeds are exposed during floods ;” and, “if they chance to be drowned, or to die when swimming on water, it will scarcely ever happen that they will be sub- merged so as to become preserved in sedimentary deposits,” since, from the lightness of the bones, the carcass would remain long afloat, and would be liable to be devoured by predaceous animals. As, with a few utterly trivial excep- tions, all the deposits in which fossils are found have been laid down in water, and more especially as they are for the most part marine, these considerations put forward by Sir Charles Lyell afford obvious ground against the anticipation that the remains of birds should be either of frequent occurrence or of a perfect character in any of the fos- siliferous rocks. In accordance with these considerations, as a matter of fact, most of the known remains of birds are either fragmentary, or belong to forms which were organised to live a terrestrial life, and were not adapted for flight. The earliest remains which have been generally referred to birds are in the form of footprints (fig. 585) impressed upon certain sandstones in the valley of the Connecticut river in the United States. These sandstones are almost cer- tainly Triassic; and if the ornithic character of these foot- prints be admitted, then Birds date their existence from the commencement of the Mesozoic period, and, for anything we know to the contrary, may have existed during the Paleozoic epoch. Boe BIRDS. The evidence as to the ornithic character of the footprints in the American Trias is as follows :— Firstly, The tracks appear to be certainly those of a biped —that is to say, of an animal which often, if not always, Fig. 585.—Footprint supposed to belong to a Bird. Triassic Sandstones of Connecticut. walked upon two legs. No living animals walk habitually upon two legs except Man and Birds, and therefore there is a prima facie presumption that the authors of these prints were birds. Secondly, The impressions are mostly tridactylous—that is to say, formed by an animal with three toes on each foot, as is the case in many Waders and most Cursorial Birds. Thirdly, The impressions of the toes show the same nu- merical progression in the number of phalanges as exists in living birds—that is to say, the innermost of the anterior toes has three phalanges, the middle one has four, and the outermost toe has five phalanges. Taking this evidence collectively, it would have seemed, till lately, tolerably certain that these impressions were formed by Birds. In spite, however, of the general resem- blance of these footprints to those of Birds, the balance of evidence at the present moment is in favour of the view that they are, in great part, and perhaps wholly, the work of Reptiles. Some of the three-toed footprints have been shown to be accompanied with the recognisable traces of the . BIRDS. 2593 impressions of a much smaller anterior pair of feet. Others of the impressions are four-toed, and must certainly have been formed by Reptiles; while the bones of Deinosaurs have actually been found in the same beds. Putting these facts together with the strong probability that the Deino- saurs in some cases temporarily or permanently adopted a bipedal mode of progression, it seems tolerably certain that most of the footprints of the Connecticut Trias were pro- duced by Reptiles, though there still remains the possibility that some are ornithic. The size and other characters of the above-mentioned im- pressions vary much, and they have certainly been produced by several different animals. In the largest hitherto discov- ered, each footprint is twenty-two inches long, and twelve inches wide, showing that the feet were four times as large as those of the African Ostrich. The animal, therefore, which produced these impressions—whether Avian or Rep- tilian—must have been of gigantic size. The first unmistakable remains of a bird have been found in the Solenhofen Slates of Bavaria, of the age of the Upper Oolites. A single unique specimen, consisting of bones and feathers, but unfortunately without the skull, is all that has hitherto been discovered ; and it has been named the Archwo- pteryx macrura. A second specimen found quite recently has not yet been described. The characters of this singular and aberrant bird, which alone constitutes the order Sawrure, will be shortly given, and need not be repeated here. In the Cretaceous rocks, not only do we find the remains of Birds of the type now existing, but we meet with the extraordinary “'Toothed Birds” (Odontornithes), which seem not to have survived this period, and which will be spoken of in greater detail later on. Lastly, almost all the existing orders of Birds are represented by the time we reach the middle of the Tertiary period, and the distribution and char- acters of the more important fossil forms will be treated of in discussing the several orders in question. CHAPTER: XSXOSvV it ORDERS OF Birps. THE class Aves may be divided into the following four sub- classes :— I. Rarir#.—Sternum raft-like, without a prominent keel for the attachment of the great pectoral muscles. The barbs of the feathers not united by the barbules. This sub-class comprises the single order of the Cursores or Running Birds, such as the Ostrich, Emeu, Cassowary, &c., all of which are destitute of the power of flight. II. Carrmyata#.—tThe sternum furnished with a prominent median ridge or keel, to which the muscles of flight are at- tached. In this sub-class are comprised the existing orders of the Natatores, Grallatores, Rasores, Scansores, Insessores, and Raptores, in all of which the power of flight is normally more or less developed. III. SavrornirHes.—The caudal vertebree numerous; the tail longer than the body, and not terminated by a plough- share-bone. The metacarpals not anchylosed. This sub- class ineludes only the single order Saurure, comprising only the single Jurassic bird, the Archeopteryx macrura. IV. OponTORNITHES.—Jaws furnished with true teeth, sunk in distinct sockets or in a continuous groove. Wings well developed or rudimentary. This sub-class comprises the two extinct orders of the Odontotorme and Odontolce, both of which are confined to the Cretaceous period. In the following are given the characters of the orders of RATITA. PASI) the Birds, with the principal fossil forms and geological range of each, so far as known :— SUB: cLAss I.—RATITA. OrDER CursoRES.—The first order of Birds is that of the Cursores, or Runners, comprising the Ostriches, Rheas, Cas- sowaries, Emeus, and the singular Apteryx of New Zealand. The Cursores are characterised by the rudimentary condition of the wings, which are so short as to be useless for flight, and by the compensating length and strength of the legs. In ac- cordance with this condition of the hmbs, many of the bones retain their marrow, and the sternum (fig. 583) is destitute of the prominent ridge or keel, to which the great pectoral muscles are attached (hence the name of Ratitew, applied by Huxley to the order). In the Ostrich, the pubic bones of the pelvis unite to form a symphysis pubis, as they do in no other bird; and in all, the pelvic arch possesses unusual strength and stability. The legs are extremely robust and powerful, and the hind-toe is entirely wanting, except in the Apteryx, in which it is rudimentary. The anterior toes are two or three in number, and are provided with strong blunt claws or nails. Zhe plumage presents the remarkable peculiarity that the barbs of the feathers, instead of being connected to one an- other by hooked barbules, as is usually the case, are remote and disconnected from one another, presenting some resemblance to havrs. The order Cursores may be divided into the two families of the Struthionide and the Apterygide—the former charac- terised by the absence of the hallux, and comprising the Ostrich, Rhea, Emeu, and Cassowary, with several extinct forms; the latter comprising only the Apteryx (fig. 586) of New Zealand, and characterised by the possession of a rudimentary hallux. As regards the distribution of the Cursores in space, the living forms are restricted to regions which le, wholly or in ereat part, to the south of the equator. Thus, the true Ostriches (Struthio) are African; the Rheas are South American; the Emeus are Australian; the Cassowaries 256 ORDERS OF BIRDS. are confined to Northern Australia, Papua, and the Indian Archipelago ; and the species of Apteryx are natives of New Zealand. Fig. 586.—Apteryx Australis. (Gould.) As regards the distribution of the Cursores in time, it would seem probable that some of the footprints of the American Trias (if ornithic at all) were produced by birds belonging to this group. In the present uncertainty as to the nature of these impressions, the first undoubted appearance of Cursorial Birds is in the Eocene Tertiary. In beds of this age in Britain (the London Clay), we have the remains of Dasornis Londinensis, a large Struthious bird, with affinities to Dinornis; and in strata of Eocene age in New Mexico, Prof. Cope records the discovery of Diatryma gigantea, a wingless bird twice the size of the living Ostrich. Gastornis, also Eocene, and sometimes placed in the Cwrsores, appears to be truly referable to the Natatores. In the Miocene and Pliocene Tertiary we have no re- mains of Cursores to notice; but in the Post-Plocene period we meet with a number of extinct forms of the order, all of which, so far, have been found in geographical provinces at present tenanted by great wingless birds. The most in- RATITA. Dio teresting of the forms in question occur in the Post-Tertiary and Recent deposits of New Zealand. In this island have been found the remains of a number of large wingless birds, which form the family of the Dinornithide, of which Dinor- nis (fig. 587) itself is the most important genus. All the ~ Fig. 587.—Skeleton of Dinornis elephantopus, greatly reduced. Post-Pliocene. New Zealand. (After Owen.) members of this group (Dinornis, Palapteryx, &c.) are large Cursorial birds, the wings being useless for flight, and fur- nished with a rudimentary humerus. The hallux is wanting (Dinornis) or present (Palapteryz). The largest species is the Dinornis giganteus, one of the most gigantic of living or fossil birds, the tibia measuring a yard in leneth, and the total height being at least ten feet. Another species, the Dinornis elephantopus (fig. 587), though not standing more NAGIER OU R 258 ORDERS OF BIRDS. than about six feet in height, was of an even more ponder- ous construction—“ the framework of the skeleton being the most massive of any in the whole class of Birds,’ whilst “the toe-bones almost rival those of the Elephant ” (Owen). The feet in Dinornis were furnished with three toes, and are of interest as presenting us with an undoubted Bird big enough to produce the largest of the footprints of the Triassic Sandstones of Connecticut. New Zealand has now been so far explored, that it seems questionable if it can retain in its recesses any living example of Dinornis ; but it is certain that species of this genus were alive during the human period, and survived up to quite a recent date. Not only are the bones very numerous in certain localities, but they are found in the most recent and superficial deposits, and they still contain a considerable proportion of animal matter; whilst in some instances bones have been found with the feathers attached, or with the horny skin of the legs still adhering to them. Charred bones have been found in connection with native “ovens;” and the traditions of the Maories contain circumstantial accounts of gigantic wingless Birds, the “Moas,” which were hunted both for their flesh and their plumage. In Madagascar, bones have been discovered of another huge wingless Post-Tertiary Bird, which must have been as large as, or larger than, the Dinornis giganteus, and which has been described under the name of Mpiornis maximus. With the bones have been found eggs measuring from thir- teen to fourteen inches in diameter, and computed to have the capacity of three ostrich-egegs. At least two other smaller species of 4piornis have been described by Grandi- dier and Milne-Edwards as occurring in Madagascar; and they consider the genus to be so closely allied to the Dinornis of New Zealand, as to prove that these regions, now so re- mote, were at one time united by land. Another point which would favour this view is the existence in the Post-Tertiary of the Mascarene Islands of a wingless bird (the Lrythro- machus Legquati), which A. Milne-Edwards considers to be allied to the living Apteryx of New Zealand. The former existence of Cursorial birds in regions now inhabited by CARINATA. 259 members of the same order is further exemplified by the occurrence of remains of birds belonging to the South American genus Rhea in the Post-Tertiary cave-deposits of Brazil. Lastly, the Post-Tertiary deposits of Australia have yielded the remains of an extinct Struthious bird allied to the Emeu, which has been described under the name of Drom«ornis. Susp-cLass JI.—CARINATA. OrpER I. NATATORES (Palmipedes)—The order of the Natatores, or Swimmers, comprises a number of Birds which are as much or even more at home in the water than upon the land. In accordance with their aquatic habit of life, the Natatores have a boat-shaped body, usually with a long neck. The legs are short, and placed behind the centre of gravity of the body, this position enabling them to act admirably as paddles, at the same time that it renders the gait upon dry land more or less awkward and shuffling. In all cases the toes are “webbed” or united by membrane to a greater or less extent. In many instances the membrane or web is stretched com- pletely from toe to toe, but in others the web is divided or split up between the toes, so that the toes are fringed with membranous borders, but the feet are only imperfectly webbed. Amongst the more important families of the Natatores may be enumerated the Penguins (Spheniscide), the Auks (Alcide), the Gulls and Terns (Laride), the Petrels (Procel- laride), the Pelicans (Pelicanus), the Cormorants (Phalacro- corax), the Gannets (Sula), the Ducks (Anatide), the Geese (Anserine), and the Swans (Cygnide). As might have been expected, the remains of Natatorial Birds are, speaking comparatively, not uncommon as fossils. The earliest traces of this order in past time appear in the Cretaceous series, which has yielded in Europe the Cimo- lornis (supposed to be allied to the Albatross), and in North America the genera Zaornis and Craculavus, the former re- lated to the Swans, while the latter has affinities with the living Graculus. In the Eocene Tertiary we meet with 260 ORDERS OF BIRDS. various interesting types of the Natatores. Among these, Gastornis is a huge and aberrant example of the Anserine, with some Grallatorial affinities, and approaching the Cwrsores in the fact that the wings were rudimentary, and the power of flight, therefore, wanting. The only known species is the Gastornis Parisiensis of the Paris basin. The Argillornis of the Eocene Tertiary appears to have been an ancient repre- sentative of the Albatross (Diomedea exulans), considerably exceeding the living species in size. Agnopterus, again, is an Eocene bird allied to the Flamingo. Under this order also probably comes the extraordinary fossil bird, recently described by Professor Owen from the London Clay (Eocene) of Sheppey under the name of Odontopteryx toliapicus. In this singular bird (fig. 588) the alveolar margins of both jaws are furnished with tooth-like denticulations, which differ from true teeth in being actually parts of the osseous sub- stance of the jaw itself, with which they are continuous. They are of triangular or compressed conical form, and are of two sizes, the larger ones resembling canines. From the consideration of all the discovered remains of this bird, Professor Owen concludes that “ Odontopteryz was a warm- PED. Fig. 588.—Skull of Odontopteryx toliapicus, restored. (After Owen.) blooded feathered biped, with wings ; and further, that it was web-footed and a fish-eater, and that in the catching of its slippery prey it was assisted by this Pterosauroid armature of its jaws.” Upon the whole, Odontopteryz would appear to be most nearly allied to the Anatidw, but the denticulation of its jaws is an entirely unique character. In the Miocene Tertiary are found the remains of various Natatorial birds, among which may be mentioned Flamingoes, CARINATA. 261 hardly separable from existing species, together with Pela- gornis, an extinct ally of the Pelicans. Of the Pliocene and Post-Tertiary Natatores, the only form requiring notice is the great extinet Cremiornis of the Post- Tertiary deposits of New Zealand. The remains of this bird indicate that it was an aberrant member of the Anserine, most nearly allied to the living Cereopsis of Australia, but resembling the Cursores in the massive construction of the hind-limbs and the rudimentary condition of the wings. OrpER IT. GRALLATORES.—The birds comprised in the order of the Grallatores, or Waders, for the most part frequent the banks of rivers and lakes, or the shores of estuaries, marshes, lagoons, and shallow pools, though some of them keep almost exclusively to dry land, preferring, however, moist and damp situations. In accordance with their semi-aquatic amphibi- ous habits, the Waders are distinguished by the great length of their legs; the increase in length being mainly due to the great elongation of the tarso-metatarsus. The legs are also unfeathered from the lower end of the tibia downwards. The toes are elongated and straight, and are never completely pal- mate, though sometimes semi-palimate. There are three anterior toes, and usually a short hallux, but the latter may be wanting. The wings are long, and the power of flight usually consider- able; but the tail is short, and the long legs are stretched out behind in flight to compensate for the brevity of the tail. The body is generally slender, and the neck and beak usually of considerable length. Amongst the more important Grallatorial Birds are the Rails (Rallide), Water-hens (Gallinule), Cranes (Gruide), Herons (Ardeidw), Storks (Ciconinw), Snipes (Scolopacide), Sandpipers (Zringidw), Curlews (Numenius), Plovers (Chara- driide), and Bustards (Ofide). As in the case of the Natatores, the earliest traces of the Waders appear to belong to the Cretaceous period, and are found in deposits of this age in the North American area. The forms in question constitute the genera Paleotringa and Telmatornis, the former being allied to the Sandpipers, while the latter is rather related to the Rails. In the Eocene Tertiary various Grallatorial birds have 262 ORDERS OF BIRDS. been detected, one of the most remarkable being a gigantic Rail (Gypsornis) from the Paris basin. Deposits of the same age in North America have yielded the wading Aletornis. In the Miocene strata of Europe are found Waders allied to the living Godwits and Storks, constituting respectively the genera Hlornis and Ibidipodia. Lastly, in the Post-Tertiary deposits are found some interesting types of (rallatores, which require notice, as they have the peculiarity that the wings were rudimentary and useless for flight. One of the most remarkable of these is the Aphanapteryx of the Post- Tertiary of the island of Mauritius, a large Ralline bird, which was incapable of flying. It was allied to the living Ocydromus, and survived into the human period, having been apparently exterminated at a comparatively late date. Equally peculiar are the 6 Si) Ss i eS 1—1 0—0 1—1 4—.4 A second great group of the Diprotodont Marsupials is represented at the present day by the existing Kangaroos (Macropus) and Kangaroo-rats (Hypsiprymnus). In this eroup the hind-legs are longer than the fore-legs; the lower incisors are nearly horizontal, and are rooted (fig. 599, a, and fig. 607); and there are no canines. Fig. 607.—Skull of the living Macropus Bennetti. (After Giebel.) The dental formula of the Kangaroos is— ee, Ee jee ea ny eee The lving genus JMacropus is represented in the Post- Tertiary deposits of Australia by species in all essential respects agreeing with the recent forms but of gigantic size, one species being as large as the Rhinoceros. The Sthenwrus and Protemnodon of the same deposits are related, on the other hand, to the Tree-kangaroos (Dendrolagus) of New Guinea. Associated with these extinct types of Kangaroos, we have also representatives of the smaller Kangaroo-rats (Hypsiprymnus and Bettongia). A third group of Diprotodonts is represented in the Post- Tertiary of Australia by the extraordinary extinct types Diprotodon and Nototherium, which were vegetable-feeders, like the living Kangaroos, but present certain peculiarities of their own. In Diprotodon (fig. 608) the two lower incisors are round and tusk-like, and there are six upper incisors, of which the two median ones are of large size, curved, and 296 ORDERS OF MAMMALIA. chisel-shaped. The incisors differ from those of the Kan- garoos, and agree with those of the Wombats, in growing from persistent pulps ; there are no canines ; there is a single Fig. 608.—Skull of Diprotodon Australis, (After Owen.) Post-Tertiary, Australia. small premolar, which is lost in aged animals; and there are four grinding molars on each side of each jaw. The dental formula is— pe ae ESE (et. 4—4 a oC ee It m 1—1 0==() feet 4.—4 2.8: The fore-imbs appear to have been about equal in size to the hind-limbs, and the mode of progression must have been quite unlike that which obtains in the Kangaroos. In size, also, Diprotodon must have many times exceeded the largest of the living Kangaroos, since the skull measures three feet in length. Nototherium (= Zygomaturus) resembles Diprotodon in some respects ; but the lower incisors are diminutive, and all the front teeth are rooted. Lastly, there is a group of Diprotodonts in which we have only the singular extinct genus Thylacoleo (fig. 609), in which the most prominent feature of the dentition is the MONOTREMATA AND MARSUPIALIA. 297 presence in either jaw of a huge, compressed, and trenchant premolar. The dental formula is— a Lt =i lea pi ae A AS —3 0—0 1—1 2) The incisors are not horizontal, as in the Kangaroos, but resemble those of the Phalangers, and the true molars are very small. Nothing is known of the skeleton of Thylacoleo beyond the skull; and the peculiar dentition has been dif- ferently interpreted by different authorities. By Professor Owen it is believed that Zhylacoleo was flesh-eating and predatory in its habits, and that it represents a type of Dipro- “Moy 1”) Ley Mathes N Fig. 609.—Skull of Thylacoleo. Post-Tertiary deposits of Australia. (After Flower.) todonts specially modified in accordance with the carnivor- ous mode of life. Professor Flower, on the other hand, com- pares the cutting premolar with the correspondingly de- veloped tooth in Hypsiprymnus, and concludes that “ Thyla- coleo is a highly-modified and aberrant form of the type of Marsupials now represented by the Macropodide and Phalan- gistide, though not belonging to either of these families as now restricted,” and he believes that its diet was of a vege- table nature. Under any view of its habits, Thylacoleo is a 298 ORDERS OF MAMMALIA. very remarkable type of the Marsupials; and it must have attained a very great size, since the length of the crown of the great premolar is not less than two inches and a quarter. Just as the lhving Kangaroos and Wombats of the Aus- tralian province find Post-Tertiary representatives within the same geographical region, so also do we find that the Poly- protodont Marsupials existed side by side with the preced- ing. Moreover, the Post-Tertiary Polyprotodonts belong to types which still exist in Australia, and which are peculiar to it. Thus the living Bandicoots (Perameles) have their Post-Tertiary representatives; and the more highly carni- vorous and predatory Thylacinus and Dasyurus of Van Die- men’s Land were preceded by closely allied forms, which ranged over the mainland of Australia. Precisely parallel phenomena are observable in North and South America, all the living Marsupials of which belong to the Polyprotodont family of the Opossums (Didelphide). Apart from the early appearance of this Marsupial type in the previously-mentioned -Dryolestes of the North American Jurassic, the Post-Pliocene deposits of the same continent have yielded bones actually referable to the livmg genus Didelphys. In South America, also, the Post-Pliocene cave- deposits of Brazil have yielded various species of the same venus. These examples, then, afford a very striking ilustra- tion of the general law that the Post-Tertiary Mammals of a given country belong in a general way to types of structure represented in the same region at the present day by forms often generically different. CHAPTER XL. ORDERS OF MAMMALIA (Continued). EDENTATA. OrverR III. Epenrata or Bruta.—The lowest order of the placental or monodelphous Mammals is that of the Hdentata, often known by the name of bruta. The name Edentata is certainly not an altogether appropriate one, since it is only in two genera in the order that there are absolutely no teeth. The remaining members of the order have teeth, but these are always destitute of true enamel, are never displaced by a second set, and have no complete roots. Further, in none of the Edentata are there any median ineisors, and in only one species (one of the Armadillos) are there any incisor teeth at all. Canine teeth, too, are almost invariably wanting. Clavicles are usually present, but are absent in the Scaly Ant-eater (Manis). All the toes are furnished with long and powerful claws. The skin ws often covered with bony plates or horny scales. The order Edentata is conveniently divided into two great sections, in accordance with the nature of the food, the one section being phytophagous, the other insectivorous. In the former section is the single living group of the Sloths (Brady- podide). In the latter are the two groups of the Armadillos (Dasypodide), and the various species of Ant-eaters (the latter constituting Owen’s group of the Hdentula). The Edentates, like the Marsupials, are singularly circum- scribed at the present day. No member of the order is at the present time indigenous in Europe. Tropical Asia 300 ORDERS OF MAMMALIA. and Africa have the Scaly Ant-eaters or Pangolins; and in Africa occurs the Edentate genus Orycteropus. South America, however, is the metropolis of the Hdentata, the Fig. 610.—Skull of a living Sloth (Bradypus cuculliger). (After Giebel.) order being there represented by the Sloths, the Armadillos, and the true Ant-eaters. It is also in South America that by far the greater number of extinct Edentates have been found ; and, as in the case of the Australian Marsupials, the fossil forms are gigantic in size as compared with their living representatives. The oldest well-known representative of the Hdentata is the Macrotherium of the Miocene Tertiary of France. This is a gigantic Edentate, intermediate in some respects be- tween the Pangolins (Janis) and the Aardwark (Orycteropus). There does not appear to have been any dermal armour, and the teeth are rootless and destitute of enamel. The toes were furnished with immense claws, which were bent in- wards upon the palms of the hands and soles of the feet, in consequence of the flexion of the first phalanges upon the metacarpals and metatarsals. The animal, therefore, doubtless walked, like the existing Ant-eaters (Myrme- cophaga), upon the outer sides of the feet. The hind-limbs were much shorter than the fore-lmbs, which to some extent would support the view that the animal was a climber ; but its great size would render it unlikely that the habits of the genus were arboreal. Another ancient genus of Edentates is the Ancylotherium of M. Gaudry. Phalanges, apparently referable to a species EDENTATA. 301 of this genus (A. priscwm) have been found in deposits which are believed to be of Eocene age. More thoroughly known, however, is the Ancylotheriwm Pentelici of the Miocene! de- posits of Pikermi in Greece. This singular form was of gigantic dimensions, and the structure of the feet was much the same as in Macrotheriwm ; but the hind-limbs_ nearly equalled the fore-limbs in length, and the animal must have been terrestrial in its habits. The forms already alluded to are the only Edentates which have hitherto been discovered in the European area, and they belong to types which cannot be paralleled precisely with any at present in existence. In the Western hemisphere the first traces of Edentates detected up to this time date from the Miocene Tertiary. In beds of this age on the Pacific coast of North America, have been found the remains of two species of gigantic Edentates, which have been re- ferred to the genus Moropus. Another species of the same genus occurs in the Lower Plocene of Nebraska; and the genus itself is regarded as the type of a peculiar family of Edentates, to which the name of Moropodidw has been given. In the Lower Phocene of Idaho and California there have also been found remains of another extinct genus—Moro- thervum—comprising large Edentates, which seem to be early representatives of the wonderful American family of the “ Gravigrade” Sloths, to be spoken of immediately. It is, however, in the late Pliocene, and more particularly the Post-Pliocene, deposits of the New World that we find proofs of the past existence of the most numerous and re- markable of the fossil Hdentata—many of these being refer- able to familes now existing in the same area. The most remarkable of the extinct types in question belong to the ereat group of the “ Ground-sloths” or “ Gravigrade ” Eden- tates, which have no direct representatives at the present day, though they have many points of affinity to the hving eroup of the Sloths (Bradypodide) of South America. The latter are entirely arboreal in their habits, and are not only adapted for a hfe of climbing, but are all comparatively small 1 The Pikermi deposits are believed by some paleontologists to be properly referable to the Pliocene. 302 ORDERS OF MAMMALIA. animals. The former, on the other hand, though in many respects similarly constructed, and likewise vegetable-feeders, were of gigantic size, and must have lived exclusively upon the ground. The most celebrated of these great Gravigrada is the genus Megatherium, of which M. Cuvieri (fig. 611) of the South American Pampas may be taken as the type. This species comprised colossal Sloth-like animals, which Fig. 611.—Megatherium Cuvieri. Post-Pliocene, South America. attained a length of from twelve to eighteen feet, with bones more massive than those of the Elephant. Thus the thigh- bone is nearly thrice the thickness of the same bone in the largest of existing Elephants, its circumference at its nar- rowest point nearly equalling its total length ; the massive bones of the shank (tibia and fibula) are amalgamated at their extremities; the calcaneum is nearly half a yard in length; the haunch-bones (ilia) are from four to five feet across at their crests ; and the bodies of the vertebre at the root of the tail are from five to seven inches in diameter, from which it has been computed that the circumference of the tail at this part might have been from five to six feet. The length of the fore-foot is about a yard, and the toes are armed with powerful curved claws, which are not developed on the fifth digit; while the pollex is wanting in the hand, and the hallux and index in the foot. It is known now that the Megathere, in spite of its enormous weight and ponder- EDENTATA. S03 ous construction, walked, hike the existing Ant-eaters and Sloths, upon the outside edge of the fore-feet, with the claws more or less bent inwards towards the palm of the hand. The skull is small, as is the brain-case proper ; and the zygoma has a strong descending process, similar to that of the same bone in the true Sloths (fig. 610). As in the great majority of the Edentate order, incisor and canine teeth are entirely wanting, the front of the jaws being toothless. The jaws, however, are furnished with five upper and four lower molar teeth on each side. These grinding teeth are from seven to eight inches in length, in the form of four-sided prisms, the crowns of which are provided with well-marked transverse ridges ; and they continue to grow during the whole life of the animal. There are indications that the snout was pro- longed, and more or less flexible; and the tongue was prob- ably prehensile. From the characters of the molar teeth it is certain that the Megathere was purely herbivorous in its habits; and from the enormous size and weight of the body it is equally certain that it could not have imitated its modern allies, the Sloths, in the feat of climbing, back down- wards, amongst the trees. It is clear, therefore, that the Meegathere sought its sustenance upon the ground; and it was originally supposed to have lived upon roots. By a masterly piece of deductive reasoning, however, Professor Owen showed that this ereat “Ground-sloth” must have truly lived upon the fohage of trees, like the existing Sloths —hbut with this difference, that instead of climbing amongst the branches, it actually uprooted the tree bodily. In this tour de force, the animal sat upon its huge haunches and mighty tail, as on a tripod, and then grasping the trunk with its powerful arms, either wrenched it up by the roots or broke it short off above the ground. Marvellous as this may seem, it can be shown that every detail in the skeleton of the Megathere accords with the supposition that it obtained its food in this way. Though principally South American, the genus Megatherium extended its range to North America, this continent having yielded the remains of a species closely allied to, or absolutely identical with, IZ Cuvier. The genus Mylodon comprises large Sloth-like animals, of 304 ORDERS OF MAMMALIA. which the best known is the Jylodon robustus (fig. 612). In its size, Mylodon robustus was smaller than the Megatherium, but it reached a length of eleven feet. In many respects Mylodon is very like Megatheriwm, and the number of the teeth is the same—viz., five upper and four lower molars on each side. The crowns of the molars, however, were flat, Fig. 612.—Skeleton of Mylodon robustus. Post-Pliccene, South America. instead of being ridged, and the anterior upper molars were separated by a gap from those behind them. The fore-feet are pentadactylous, and the posterior tetradactylous, the two external digits being nailless. Like Megatherium, the genus Mylodon is known to have ranged into North America. Scelidotherium is another South American genus, closely allied to Mylodon, but comprising forms of smaller size and less massive construction, while the skull was elongated in shape, and other osteological differences existed as well. Megalonyx, again, comprises large Sloth-like Edentates from the Post-Pliocene of North America. It has the same dental formula as Megatherium and Mylodon, but the crowns of the molars are excavated centrally and have a prominent margin, EDENTATA. 305 while the first molar is large, pointed, and separated from those behind it by a wide gap. The fore-limbs are shorter than the hind-limbs, and the caleaneum is excessively long. In the Pliocene or Post-Pliocene deposits of Cuba occur the remains of the genera Megalocnus and Myomorphus, which are nearly allied to Megalonyzx. The great Ground-sloths, of which the principal types have now been briefly glanced at, not only have no repre- sentatives at the present day, but do not even appear, so far as certainly known, to have survived into the earlier por- tion of the Recent period, their last recorded occurrence being in the bone-caves of Brazil. On the other hand, it is in the deposits of these caves that we first meet with remains of the existing Sloths (Bradypodide), which make their appearance here under various extinct types, such as Celodon and Ochothervum. The living families of the Dasypodide and Myrmeco- phagide, both characteristic of South America, were repre- sented, similarly, by numerous interesting types which flour- ished in the same geographical area during late Pliocene and Post-Pliocene times. Most of these types, though clearly representative of those now existent, differed from the latter in points of generic importance, while many were of com- paratively gigantic dimensions. Thus, side by side with the huge Megatheroids which took the place of the existing herbivorous Sloths, we find the colossal Glyptodons, repre- senting the little banded and cuirassed Armadillos (Dasy- podide) of the South America of to-day, and, like these, adapted for a carnivorous diet. Taking Glyptodon itself (fig. 613) as the type of this singular group of extinct Armadillos, we are presented with a large Edentate, the upper surface of which was protected by an armour formed of dermal ossifications or scutes. The head is covered with a helmet of bony plates, and the tail was enclosed in a com- plete cylindrical casing similarly composed. The trunk- armour is formed of nearly hexagonal bony scutes, forming a massive dome, for the support of which the skeleton is specially modified. Thus the last cervical and first two dorsal vertebre are anchylosed to form a single bone VOI ls U 306 ORDERS OF MAMMALIA. (“trivertebral bone” of Huxley), which articulates by a movable hinge-joint with the remaining dorsal vertebree, which are likewise anchylosed to form a kind of “tunnel or arched bridge of bone.” The last two lumbar vertebree are also fused with the sacral and caudal to form a contin- Fig. 613.—Glyptodon clavipes Post Pliocene, South America. uous bony mass, whilst the ila are of enormous size. Un- like the living Armadillos, Glyptodon possesses no movable bands in its armour, the scutes—-which are characteristically sculptured in the different species — being in contact by their edges, though not anchylosed. The animal, therefore, possessed no power of rolling itself up for defence against its enemies. There are no canine or incisor teeth in Glyptodon, but there are eight molars on each side of each jaw, and the crowns of these (fig. 614) are fluted and almost tri- lobed. The teeth form a continuous series, each being long, arched, and deeply fur- Fig. 614.—First and second molars of Glyp- Towed with two parallel todon casper, viewed from above. (After Bur- OF rhibisteny’ grooves on each side; and all grew from permanent pulps. The feet are massive, and the ungual phalanges are short, compressed, and hoof-like—the fore-feet being tetra- dactylous, and the hind-feet with four or five toes. The length of Glyptodon clavipes (fig. 613), from the tip of the snout to the end of the tail, was more than nine feet. The genus Schistopleurum comprises gigantic Armadillos EDENTATA. 307 which occur in South America along with Glyptodon. Schisto- pleurum typus was eight feet long, including the tail; and the carapace is three feet in height. No direct representatives of the Glyptodons are known to exist at the present day ; but the true Armadillos (fig. 615), with a variable number of movable bands in their dorsal armour, appear in both the late Plocene or Post-Tertiary accumulations of the great plains of South America and also in the cave-deposits of Brazil. Some of these forms belong to well-known living generic or sub-generic types, such as Fig. 615.—The living three-banded Armadillo (Tolypeutes conwrus), one-third of the natural size. (After Murie.) Dasypus, Xenwrus, and Hutatus ; while others are referable to extinct and comparatively gigantic forms, such as Chlany- dothervum, Pachytherium, &c. Of these, Chlamydotherium attained a size equal to that of the existing Rhinoceroses. Lastly, the South American Ant-eaters (I/yrmecophagide) are represented in the cave-deposits of Brazil by the extinct Glossotherium. 308 CHAPTER XLI. ORDERS OF MAMMALIA (Continued). SIRENIA AND CETACEA. OrpER IV. StrentA.—This order comprises no other living animals except the Dugongs and Manatees, which are often placed with the true Cetaceans (Whales and Dolphins) in a common order. There is no doubt, in fact, but that the Sirenia are very closely allied to the Cetacea, and though they are to be regarded as separate orders, yet they may be advantageously considered as belonging to a single section, which has been called J/utilata, from the constant absence of the hind-hmbs. The Sirenia agree with the Whales and Dolphins in their complete adaptation to an aquatic mode of life (fig. 616) ; Fig. 616.—Side-view of young Munatus Americanus, greatly reduced in size; n, Nostrils. (After Murie.) especially in the presence of a powerful caudal fin, whieh differs from that of Fishes in being placed horizontally and in being a mere expansion of the integuments, not supported by SIRENIA AND CETACEA. 309 bony rays. The hind-limbs are wholly wanting, and there is no sacrum. The anterior limbs are converted into swimming- paddles or “ flippers.” — The snout is fleshy and well-developed, and the nostrils are placed on its wpper surface, and not on the top of the head, as in the Whales. Fleshy lips are present, and the upper one usually carries a moustache. The skin is covered with scattered bristles. The head is not dispropor- tionately large, as in the true Whales, and is not so gradually prolonged into the body as it is in the latter. There may be only six cervical vertebre. There are no clavicles, and the digits have no more than three phalanges each. Zhe animal is diphyodont (Manatus) or monophyodont (Halicore) ; the permanent teeth consisting of molars with flattened crowns adapted for bruising vegetable food, and wneisors which are present in the young animal, at any rate. In the extinct fhytina it does not appear that there were any incisor teeth. The only existing Sirvenia are the Manatees (Manatus) and Fig. 617.—A, Side-view of the skull of the Dugong (Halicore), showing the tusk-like upper incisors ; B, Side-view of the skull of Manatee (Manatus). (After Cuvier.) the Dugongs (Halicore), often spoken of collectively as “sea- cows,” and forming the family of the Manatide. The Manatees (fig. 617) are characterised by the posses- sion of numerous molar teeth, and of two small upper in- cisors, which are wanting in the adult animal. They are large animals, ten feet or more in length when fully grown, and they live in shallow water near the coast, or ascend rivers for considerable distances, their food being principally aquatic plants. 1 All the Sirenia possess a rudimentary pelvis, and in the extinct Halitherium a small femur is present in addition. 310 ORDERS OF MAMMALIA. The Dugongs (Halicore, fig. 617, 4) have ~~ or Cae 5—9d 6—6 molar teeth in the young condition, but these are never all in use at one time. The molars are without enamel, and are single-rooted. Inferior incisors are present in the young animal, but are wanting in the adult. The upper jaw carries two permanent incisors, which are entirely concealed in the jaw in the females, but which increase in size in the males with the age of the animal, till they become pointed tusks. The Dugongs are very similar in appearance and habits to the Manatees, but they are more exclusively marine animals, and feed chiefly upon sea-weeds. The genus Riytina, at one time abundant on the north- west coast of North America, appears to have been com- pletely exterminated about the middle of the eighteenth century. In this curious type there were no true teeth, but the place of the molars was taken by large lamelliform fibrous structures, one on each side of each jaw. As regards their distribution in time, the earhest known remains of this order appear in the Eocene Tertiary of Egypt, where we find the Hotheriwm Egyptiacum, apparently allied to the living Manatees. Of the same age, perhaps, is the interesting form described by Owen from the Tertiary of Jamaica under the name of Prorastomus sirenoides. This type is remarkable as possessing upper and lower canines in addi- tion to incisor and molar teeth, the dental formula being— a ii 5-—=5 5 =o aire ie Ci ee a ae Soe 3—3 (2) t——1 5=—) 3I—9 The molars are enamelled, and the incisors are small; the genus thus appearing to be allied to the Manatees, though of a more generalised type. In the Miocene period Sirenians appear to have been comparatively abundant, though mostly referable to extinct types. In deposits of this age in America, however, occur remains which have been referred to the existing genus Manatus. The most important Miocene genus, extending its range into the Pliocene, is Halitheriwm (fig. 618), the skeleton of which is now tolerably well known. In this SIRENIA AND CETACEA. Sale: genus the general conformation of the skeleton is like that of Manatus, though with some points of relationship to the Dugongs. One of the most remarkable features in the skeleton is the presence of a rudimentary femur, no other TENT CTH! ENT Te l nS Fig. 618.—Mounted skeleton of Halitherium in the Heidelberg University Museum. (After Murie.) bones belonging to the hind-lmb having been hitherto dis- covered. As regards the dentition, there are tusk-like upper incisors (as in Halicore), combined with enamelled molars (as in Manatus). The molars are five or six in number on each side of each jaw, and the anterior ones seem to have had vertical successors. The posterior molars are two- or three- rooted, with complex crowns, the pattern of which reminds one of the corresponding teeth in Hippopotamus (fig. 619). Fig. 619.—Two of the lower molars of Halitherium Cuvieri, viewed from above. Miocene Tertiary. (After Blainville.) The genus Felsinotherium of the Tertiary of the South of Europe is closely allied to Halitherium, and has five molars on each side of each jaw. Crassitherium, from the Plocene of Belgium, is so called from the thick walls of its skull, and is supposed to be allied to Rhytina. Lastly, the remains of 312 ORDERS OF MAMMALIA. the recently exterminated Rhytina occur in the Post-Pliocene of Siberia. The genus Deinotheriwm referred to this order by De Blainville, and still retained in this position by Pictet, will be here considered as belonging to the order of the Proboscidea. OrpDER V. CETACEA.—In this order are the Whales, Dol- phins, and Porpoises, all agreeing with the preceding in their complete adaptation to an aquatic life. The body is com- pletely fish-like in form; the anterior limbs are converted into swimming-paddles or “ flippers ;” the proximal bones of the Jore-limbs are much reduced in length, and the succeeding bones are shortened and flattened, and are enveloped in a tendinous skin, thus reducing the limbs to oar-like fins; there are no external ears; the posterior limbs are completely absent ; and there is a powerful, horizontally-flattened caudal fin, sometimes accompanied by a dorsal fin as well. In all these characters the Cetacea agree with the Strenia, except in the one last mentioned. On the other hand, the nostrils, which may be single or double, are always placed at the top of the head, con- stituting the so-called “ blow-holes” or “ spiracles ;” and they are never situated at the end of a snout. The body is very sparingly furnished with hairs, or the adult may be conipletely hairless. The head is generally of disproportionately large size, and is never separated from the body by any distinct constric- tion or neck, The lumbar region of the spine is long, and, as in the Strenia, there is no sacrum, and the pelvis is repre- sented by a single bone (the ischium) on each side. A rudi- mentary femur may be present, and Balena mysticetus has a cartilaginous tibia as well, There are no clavicles, and some of the digits may possess more than three phalanges each. Lastly, the adult is either destitute of teeth, or, with the single exception of the Zeuglodontide, is monophyodont—that is to say, possesses but a single set of teeth, which are never re- placed by others. When teeth are present, they are usually conical and numerous, and, except in the Zeuglodonts, they are always of one kind only. The Cetacea may be divided into the five families of the Balenide or Whalebone Whales, the Delphinide or Dolphins and Porpoises, the Catodontide or Sperm Whales, SIRENIA AND CETACEA. ole the Rhynchoceti or Ziphioid Whales, and the Zeuglodontidw. Of these, the Balenidw are often spoken of as the “tooth- less” Whales, whilst the other four families are called the “toothed”? Whales (Odontoceti). Fam. 1. Balenide—The Balenide or Toothless Whales are characterised by the total absence of teeth in the adult (fig. 620). Teeth, however, are present in the fcetal Whale, Fig. 620.—Skull of the Right Whale (Bulena mysticetus). (After Owen.) but they never cut the gum. The place of teeth is supplied by a number of plates of whalebone or “baleen” attached to the palate; hence the name of “ Whalebone Whales” often given to this family. They are the largest of living animals, and may be divided into the two sections of the Smooth Whales, in which the skin is smooth, and there is no dorsal fin (as in the Greenland Whale), and the Purrowed Whales, in which the skin is furrowed, and a dorsal fin is present (as in the so-called Finner Whales and Hump-backed Whales). So far as at present known, the importance of the Lale- nide, from a paleontological point of view, is not great. It is very doubtful if any member of this group has been found in any Secondary deposit. The only exception to this state- ment—and it is a doubtful one—is that of the cervical verte- bree of Palwocetus, which were discovered in glacial accumu- lations near Ely, and are supposed to have been washed out of the Kimmeridge Clay (Jurassic). These are believed to belong toa Whalebone Whale. In the Miocene and Pliocene Tertiary we meet for the first time with undoubted remains of Balenide. Of this nature are the extinct Hoplocetus of the Pliocene, and the Cetothervwm and Cetotheriopsis of the 314 ORDERS OF MAMMALIA. “Sarmatian ” deposits, all of which appear to be more or less closely related to the living Finner Whales (Balenoptera). The lving genus Balena appears for the first time in the Phocene of Europe ; and it is probable that the ear-bones or “ cetotolites,’ which occur in the Red Crag (Phocene), are, in some instances at any rate, referable to members of the Balenide. Fam. 2. Catodontide.—The family of the Catodontide, or Physeteride, comprises the Sperm Whales or Cachalots, with which we commence the series of the Toothed Whales (Odon- toceti). They are characterised by the fact that the palate is destitute of baleen-plates, and the lower jaw possesses a series (about fifty-four) of pointed conical teeth, separated by inter- vals, and sunk in a common alveolar groove, which is only imperfectly divided by septa. The upper jaw is also in reality furnished with teeth—but, with a single partial ex- ception, these do not cut the gum. Remains of Cachalots (Physeter) occur in the Pliocene and Post - Tertiary deposits, and their existence has even been indicated in the Miocene Tertiary. They are, however, of no special importance. Fam. 3. Delphinide.—This family includes the Dolphins, Porpoises, and Narwhal, and is characterised by usually pos- sessing teeth in both jaws; the teeth being numerous, and conical in shape. ‘The nostrils, as in the last family, are united, but they are placed further back, upon the top of the head. The single blow-hole or nostril is transverse, and mostly crescentic or lunate in shape. The head is by no means so disproportionately large as in the former families, usually forming about one-seventh of the entire length of the body. The genus Delphinus, comprising the common Dolphins, appears to date from the Miocene Tertiary, and is well repre- sented in deposits of Pliocene age. In Miocene strata also occur the Delphinoid remains which have been referred to the genera Priscodelphinus, Stereodelphis, and Champsodelphis. Fam. 4. Rhynchoceti—This family is allied to that of the Cachalots or Sperm Whales, and includes the so-called “ Ziphioid Whales.” They are distinguished by the posses- SIRENIA AND CETACEA. 315 sion of a pointed snout (the “beak” or “rostrum ”), single blow-hole, and small dorsal fin; and by their dentition. The upper jaw is edentulous, any teeth which may be pre- sent not cutting the gum. The lower jaw, on the other hand, possesses usually a single pair of teeth, which are sometimes tusk-like, but which in other cases are concealed by the gum. The rostrum of these Cetaceans is of great density, and has often been preserved in a fossil state, usually presenting itself as a bony cylinder or elongated cone, generally more or less water-worn. Upon fossils of this nature have been Fig. 621.—The common Dolphin (Delphinus delphis). founded the genera Choneziphius and Belemnoziphius, both of which occur in the so-called “ Crags” (Pliocene). The genus Ziphius also occurs in the Crag, but unlike the preceding it is represented by existing species. Besides the “ beaks,” some fossil teeth have been found, which may perhaps be referable to members of this family. Fam. 5. Zeuglodontide.— The members of this family differ from-all existing Odontoceti in the possession of molar teeth implanted by two distinct fangs. Incisor teeth are likewise present, and the animal is diphyodont. The Zeuglo- donts are entirely extinct, and they are exclusively confined to the Eocene, Miocene, and Pliocene periods. The chief genera are Zeuglodon and Squalodon. Zeuglodon (tig, 622) is distinguished by its elongated snout, conical incisors, and molar teeth with triangular ser- rated crowns, implanted in the jaw by two roots. Each molar looks as if it were composed of two separate teeth united on one side by their crowns; and it is this peculiarity 36 ORDERS OF MAMMALIA. which is expressed by the generic name. The species of Zeuglodon are Eocene and Miocene, one of the best known being the great Z. cetoides of the Middle Eocene (Jackson Beds) of the United States, which attained a length of seventy feet. By Professor Huxley, Zeuglodon is regarded as in some respects intermediate between the true Cetaceans and the uae a Fig. 622.—Zeuglodon cetoides. A, Molar tooth, natural size; B, Vertebra, reduced. From the Middle Eocene of North America. (After Lyell.) Carnivorous family of the Seals. On this point this eminent naturalist remarks: “The skull of this great Eocene sea- monster, in fact, shows, by the narrow and prolonged inter- orbital region; the extensive union of the parietal bones in a sagittal suture; the well-developed nasal bones; the distinct and large incisors implanted in preemaxillary bones, which take a full share in bounding the forepart of the gape ; the two-fanged molar teeth with triangular and serrated crowns, not exceeding five on each side in each jaw; and the existence of a deciduous dentition,—its close relation with the Seals. While, on the other hand, the produced rostral form of the snout, the long symphysis, and the low coronary process of the mandible, are approximations to the Cetacean form of those parts.” The genus Squalodon is nearly related to Zeuglodon, but the teeth are more numerous; and the double-fanged molars (fig. 623) are more compressed and pyramidal in form. “ The nasal bones are very short, and the upper surface of the rostrum presents the groove, filled up during life by the SIRENIA AND CETACEA. Ba prolongation of the ethmoidal cartilage, which is so charac- teristic of the majority of Cetaceans” (Huxley). The species of Squalodon all belong to the Miocene and Phocene Tertiary. Fig. 623.—Three of the lower molars of Squalodon. Miocene Tertiary. (After Scilla.) The genus Sawrocetes has been founded for the reception of another Zeuglodont, in which there were double-fanged teeth with conoid crowns. The remains on which this genus are based are from strata of Tertiary age, near Buenos Ayres, and they indicate an animal much smaller than the true Zeuglodons. Lastly, it would appear probable that the genus Balenodon, founded upon teeth from the Red Crag (Phocene), is really referable to this family, and probably to the genus Squalodon. In part, however, teeth of Ziphioid Whales have also been included under this title. By Owen, Balwnodon is regarded as comprising teeth of a Cetacean nearly allied to the living Sperm Whale. 318 CHAPTER.” XhTE ORDERS OF MAMMALIA (Continued). UNGULATA. OrDER VI. UneuLatra.— The order of the Ungulata, or Hoofed Quadrupeds, is one of the largest and most import- ant of all the divisions of the Mammalia. It comprises three entire old orders—namely, the Pachydermata, Solidun- gula, and Ruminantia. The first of these old divisions—that of the Pachydermata —included the Elephants, Rhinoceros, Hippopotamus, Tapirs, and the Pigs, all characterised, as the name implies, by their thick integuments. The name is still used to express this fact, though the order is now abandoned, and is merged with that of the Ungulata ; the Elephants alone being removed to a separate order under the name of Proboscidea. The second old order—that of the Solidungula or Soli- pedes—included the Horse, Zebra, and Ass, all characterised by the fact that the foot terminates in a single toe, encased in an expanded hoof. The name Solidungula is still retained for these animals, as a section of the Ungulata. The third old order—that of the Ruminantia—includes all those animals, such as Oxen, Sheep, Goats, Camels, Giraffes, Deer, and others, which chew the cud or “ruminate,” and have two functional toes to each foot, encased in hoofs. The name Ruminantia is still retained for these animals, as constituting a most natural group of the Ungulata. All these various animals, then, are now grouped together PERISSODACTYLA. 319 into the single order of the Ungulata, or Hoofed Quadrupeds, and the following are the characters of the order :— All the four limbs are present, and that portion of the toe which touches the ground is always encased in a greatly-ex- panded nail, constituting a “hoof.” There are rarely more than four full-sized toes to each limb. Owing to the encase- ment of the toes in hoofs, the limbs are useless for prehension, and only subserve locomotion ; hence clavicles are always want- ing in the entire order. There are always two sets of enamelled teeth, so that the animal is diphyodont. The molar teeth are massive and have broad crowns, adapted for grinding vegetable substances. The order Ungulata is divided into two primary sections : the Perissodactyla, in which the toes or hoofs are odd in number (one or three, or rarely five), and the Artiodactyla, in which the toes are even in number (two or four). Both these great sections were differentiated as early as the Eocene Tertiary, in which formation are found the oldest remains of Uneulates which have been as yet discovered. The ancestral types from which these sections were derived are still unknown to us, but it 1s.to be expected that these will be found to possess the full five digits which are nor- mally present in the mammalian limb. It might, therefore, be not unadvisable to create a third section of the Ungulata, which might be termed Teleodactyla, for the reception of those forms in which the foot is five-toed. In the mean- while, however, the few known pentadactylous Ungulates (the Coryphodontia) may be temporarily retained in the Perissodactyle section of the order, with which they have affinities in other respects. SECTION A. PERISSODACTYLA. The section of the Perissodactyle Ungulates includes the living types of the Rhinoceroses, Tapirs, and Horses, to- gether with a vast number of extinct forms, only the more important of which can be alluded to here. The characters of the section are as follows :— The hind-feet are odd-toed in all (fig. 624, B), and the fore- 320 ORDERS OF MAMMALIA. feet in all except the Tapirs and Brontotheride. The dorso- lumbar vertebre are never less than twenty-two im number. The Jemur has a third trochanter. The horns, of present, are not paired (except in the extinct genus Diceratherium). Usually there is only one horn, but if there are two, these are placed vn the middle line of the head, one behind the other. In neither case are the horns ever supported by bony horn-cores. The stomach is simple, and is not divided into several compartments ; and there is a large and eapacious cecum: The typical state of matters in the Perissodactyles is that the third digit of the foot should be pre-eminently and sym- metrically developed, and should either exist alone (Zqwus), or should be flanked by the second and fourth digits, the Fig. 624.—Feet of Ungulata. a, Fore-foot of Tapir(Tapirus Maloyanus); B, Perissodactyle fore-foot of Rhinoceros Sumatrensis; c, Artiodactyle foot of Pig (Sus scrofz). The figures indi- cate which of the normal five digits are present in each foot. (After Flower.) size and length of these varying in different cases, but always falling short of the dimensions of the central di@it (Rhin- oceros, fig. 624, B). No living Perissodactyle Ungulate pos- sesses the inner or first digit on either fore or hind feet. The’ Tapirs, however, have a small fifth digit (fig. 624, a) devel- oped on the fore-feet, the inner digit of which is still wanting ; the extinct Orohippus has similarly the fifth digit developed PERISSODACTYLA. 321 in the fore-foot; and in the extinct Hohippus there is even a rudimentary first digit or pollex. Lastly, in the extinct Coryphodonts, which, as before said, might with some advan- tage be placed in a separate section (7¢eleodactyla), the feet are furnished with the full complement of five digits on all the feet, and all of these are sufficiently developed to touch the eround. Provisionally admitting these ancient five-toed types into the Perissodactyla, we may divide this section of Un- eulates into the seven principal families of the Coryphodon- tide, Rhinoceride, Tapiride, Brontotheride, Paleotheride, Macrauchende, and Equide. Of these, the families of the Rhinoceride, Tapiride, and Equide alone survive ; and widely separated as they are in many important characters, the in- tervals between them are to a large extent filled up by an extensive series of fossil forms. Fam. 1. Coryphodontide—In this family is comprised the genus Coryphodon only, this beg apparently identical with the Bathmodon of Cope. First founded by Owen upon fragmentary remains discovered in the Eocene Tertiary of Britain, the characters of the genus have now been largely elucidated by Professor Marsh from the much more ample material obtained from strata of the same age in North America. The genus Coryphodon comprises large Tapir- hke animals, all belonging to the period of the Eocene Tertiary, and having an average size about equal to that of the living Tapirs. The skull (fig. 625, A) is of the Perisso- dactyle type, and is hornless, the comparatively small size of the nasal bones indicating that the nose was not prolonged into a proboscis. The brain is remarkably small, and of an altogether inferior type of organisation—casts of the brain- case indicating that the cerebellum was large, the cerebral hemispheres inuch reduced in size, and “the olfactory lobes large and entirely in advance of the hemispheres ” (Marsh). The dentition is complete, the dental formula being— _3—3 1—1 4——4 “06 ; pm ; Mm = 44. oes? a i ae egies OS (Ss) Oo 9 oO The canines are not excessively developed, and the molars are of the Tapiroid type, and have two transverse crests or WOIGS 10: x oL2 ORDERS OF MAMMALIA. ridges. The limbs are short; the femur has a third troch- anter ; and the feet are furnished with five digits each (fig. 625, B and Cc), all of these being functionally complete. Fig. 625.—a, Outline of skull and brain-cavity of Coryphodon hamatus, viewed from above, one-fifth of the natural size; B, Fore-foot of Coryphodon, one-third of the natural size; c, Hind-foot of Coryphodon, one-third of the natural size. Lower Eocene, North America. (After Marsh.) , Fam, 2. Rhinoceride.—This family comprises only a single living genus, the genus Lhinoceros, unless, indeed, the little Hyrax is to be placed here. The Rhinoceroses are extremely large and bulky brutes, having a very thick skin, which is usually thrown into deep folds.. The muzzle is rounded and blunt, and there are el molars, with tuberculate crowns. (ae There are no canines, but there are usually incisor teeth in both jaws. The skull is pyramidal, and the nasal bones are generally enormously developed. The feet (fig. 624, B) are PERISSODACTYLA. oe furnished with three toes each, encased in hoofs. The nasal bones usually support one or two horns, composed of longi- tudinal fibres, which are agglutinated together, and are of the nature of epidermic growths, somewhat analogous to hairs. The Rhinoceroses live in marshy places, and subsist chiefly Fig. 626.—a, Under sufface of the skull of Rhinoceros Etruscus, one-seventh of the natural size—Pliocene, Italy; 8, Crowns of the three true molars of the upper jaw, left side, of Rhinoceros megarhinus (R. leptorhinus, Falconer), one-half the natural size— Pliocene, France. (After Falconer.) on the foliage of trees. They are exclusively confined at the present day to the warmer parts of the Old World; but an extinct species (Rhinoceros tichorhinus) formerly inhabited England, and ranged over the greater part of Europe. The genus Rhinoceros appears for the first time in the Miocene Tertiary, and still survives; while it is represented in the earlier period of the Eocene by allied genera. Through- out its long range the genus exhibits a considerable amount of variability, and even the now existing species differ from one ORDERS OF MAMMALIA. one another in points of considerable importance, some of which may be briefly alluded to. In the first place, as regards the dentition considerable differences obtain among different species of the genus. The typical dental formula is— _1—1 0—0 0—0 4-—4 3—3 a Op =k G Se = 1—1 0—0 0—0 4+—4 In many species, such as the living two-horned Rhinocer- oses of Africa, there are no incisor teeth at all in the fully- erown animal. In other cases (¢.g., in the living &. Indicus) there are two incisors in the front of both the upper and the lower jaw, and the lower incisors are longer and more pointed than the upper. In some of the Miocene Rhinoceroses (such as R. Schleiermacheri) the front of the lower jaw carries four teeth, of which the two central ones are small, while the outer ones are long and pointed. These tusk-lke teeth are generally regarded as an external pair of incisors, but they are looked upon by Gervais and Gaudry as being truly canines. In the hornless Miocene Rhinoceroses, which con- stitute the genus Acerotheriwm, the condition of matters is usually as just mentioned. That is to say, the lower jaw carries a pair of minute central incisors and a pair of tusk- like lateral incisors (canines ?); but the former may be wanting, and in one species of the genus the front of the lower jaw carries a series of eight teeth, six incisors and two canines. Lastly, the Rhinoceros Sivalensis of the Siwalk Hills is stated by Falconer to possess six lower incisors. On each side of both lower and upper jaws there exists in the Rhinoceroses a continuous series of seven grinding teeth, of which the first four are premolars, and the hinder three are molars (fig. 626 a). The crowns of these (fig. 626 B, and figs. 627 and 628) are of the Palotherian type, there being two principal transverse tracts of dentine, separated by an anterior and posterior valley, not filled up with cement. Another point in which the Rhinoceroses differ remark- ably from one another is in the form and development of the nasal bones, these differences being due to the absence PERISSODACTYLA. 325 or presence of horns and the variable development of these appendages when present. In the Miocene period we meet with various species of Rhinoceroses which are entirely Fig. 627.—Penultimate molar of the Fig. 628.—Penultimate molar of the ~ lower jaw of Rhinoceros megarhinus, lower jaw of Rhinoceros tichorhinus, two-thirds of the natural size. Post- two-thirds of the natural size. Post- Pliocene. Pliocene. devoid of horns, and which are grouped together under the generic or sub-generic title of Acerotherium. In these forms (fig. 629) the nasal bones are very greatly reduced in size, though they vary in their dimensions in different species. Fig. 629.—Skull of Acerotherium (Rhinoceros) incisivum, one-seventh of the natural size. Miocene Tertiary. (After Kaup.) It may be added here, that in addition to the absence of horns the species of Acerothervwm are distinguished by the low crowns of the premolar and molar teeth, the general presence of two or more lower incisors additional to the single pair normally present, and the fact that the fore-feet are typically or always four-toed (as in the living Tapirs). 326 ORDERS OF MAMMALIA. There is thus good reason for separating Acerotherium gener- ically from Lhinoceros. The typical Rhinoceroses all possess immensely- devlenes nasal bones, to serve for the support of a horn or horns, this purpose being occasionally further subserved by the partial or complete ossification of the septum between the nostrils. We may therefore divide the species of Rhinoceros, in accordance with this character, into three groups :— 1. Those in which the nasal septum remains unossified (Rhinoceros megarhinus). 2. Those in which the nasal bones are strengthened by the partial ossification of the nasal septum, giving rise to an incomplete bony partition or “cloison” between the nostrils (R. Etruscus and RL. hemitechus). Those in which the nasal septum is completely ossified, and the nostrils are thus separated by an unbroken partition or “cloison.” This condition is coincident with the great development of the horns, and is especially well seen in the Woolly Rhinoceros (2. tichorhinus, fig. 630). Fig. 630,—Skull of the Tichorhine Rhinoceros, the horns being wanting. One-tenth of the natural size. Post-Pliocene deposits of Europe and Asia. The horns of the Rhinoceroses are, as has been mentioned, epidermic structures, and are totally distinct in their nature from the horns of the Hollow-horned Ruminants or of the Deer. In the so-called “unicorn ” Rhinoceroses there exists but a single horn placed upon the nasal bones in the median. line of the head. In the “bicorn” Rhinoceroses, on the PERISSODACTYLA. BOT other hand, there are two of these appendages, also placed upon the nasal bones in the median line of the head, the posterior horn being shorter than the anterior, or differing from it in form. While the true Rhinoceroses have invariably a median horn or horns, we shall see shortly that there existed allied types (viz., Colonoceras and Diceratheriwm) in which the horns were paired. Even excluding Acerotherium, we find true forms of Rhinoceros in existence as early as the Miocene period (R. Schleiermacheri, R. pachygnathus, &c.); and there are numerous fossil species in the Pliocene and Post-Plocene deposits of the Old World. In the New World the genus Rhinoceros itself does not appear to be represented, but the Miocene and Pliocene deposits of North America have yielded several species of Acerotherium. Of the fossil forms of — Rhinoceros, the most important are f. tichorhinus, R. mega- rhinus, R. hemitechus, and R. EHtruscus. The Rhinoceros tichorhinus (fig. 630) is generally known as the “ Woolly Rhinoceros,” from its possession of a woolly covering. Its skin was foldless, and it possessed two horns, of which the anterior one was very large. The limbs are extremely stout, and the nostrils are completely separated by an osseous septum. &. tichorhinus is essentially a north- ern form, and has the same distribution im space as the Mammoth, except that it did not cross Behring’s Straits, and is therefore not found in America. In ¢ime, it is younger than the Mammoth, not being found in the pree-glacial forest- bed of Norfolk, and occurring for the first time in the Lower Brick-earths of the Thames valley (pree-glacial, but younger than the “forest-bed”). It is therefore essentially a Post- glacial Mammal, and it is mainly found in quaternary cave- deposits and valley-gravels. The Rhinoceros hemitechus of Falconer (=the &. leptorhinas of Owen) is also provided with two horns, but is of a much more slender build than the Tichorhine form. The nasal bones are slender, and the nostrils are separated by a partially - ossified septum. The adult animal possesses neither incisor nor canine teeth. Like the preceding, &. hemitechus is exclusively Post-Plocene in its distribution, 328 ORDERS OF MAMMALIA. and is found in cave-deposits and in the Thames valley Brick-earths. The Rhinoceros megarhinus of Christol (=the R. leptorhinus of Cuvier and Falconer) is also bicorn, and resembles AR. hemitechus in being of comparatively slender build. It is distinguished, however, by the enormous development of the nasal bones and the absence of the “ cloison” or bony parti- tion between the nostrils. This form (fig. 627) is found in the Phocene beds of Italy and France, and also occurs in the pre-glacial forest-bed of Cromer and the Lower Brick- earths of the Thames valley. Rhinoceros Etruscus (fig. 626, A) is also bicorn, and has the nostrils partially separated by a “demi-cloison” or in- complete bony partition, which “strengthened the basement of the anterior horn.” This species is found in deposits of Pliocene age, and occurs also in the Post-Pliocene (as in the Cromer forest-bed). In addition to Rhinoceros and Acerotherium, the Tertiary rocks have yielded various other forms of Rhinoceridw, some of which depart very widely from the general type. The oldest known forms are Amynodon and Colonoceras, both of which are found in the Eocene Tertiary of North America. In Amynodon there were no horns, and there were both upper and lower canines, while none of the premolars were lke the molars. Colonoceras, again, is very closely allied to the Tapiroid genus Hyrachyus, but it has the curious char- acter that the nasal bones carried two very rudimentary osseous protuberances for the support of a pair of minute horns ; these appendages, however, being placed symmetrically on the sides of the head, instead of being situated one behind each other in the middle line. The possession of symmetri- cally-placed transverse horns is, however, a more conspicuous feature in the Miocene genus Diceratheriwm, which nearly equalled the existing Rhinoceroses in point of size, and closely resembled them in other structural characters, except that the fore-feet are four-toed. The genus is North American, as is also the curious Hyracodon of the Miocene, in which horns were completely wanting, and in which there is the pte) PERISSODACTYLA. 32 generalised feature that the dentition was complete, there being six incisors and two canines in each Jaw. In the later Tertiary deposits of Patagonia have been found the remains of another generalised type, which may perhaps be placed here, and which has been described under the name of Homalodontotheriwm. In this form there is the complete dentition of forty-four teeth, placed in a continuous series, and of nearly equal height. The molars are like those of Rhinoceros, to which the genus may be supposed to be allied through Hyracodon. Lastly, we may mention here the singular Elasmotheriwm of the Post- Pliocene of northern, central, and southern Europe, which was allied to the Rhinoceros, but with various quite peculiar characters. The body was of very large size, the leneth probably not falling short of fourteen or fifteen feet, and the skull seems to have carried two mesially-placed horns, of which the posterior one was much the largest. The nasal septum is ossified, as in various species of Ahinoceros. The limbs, however, are unknown; and the molars are not at all of the Rhinoceroid pattern, but, on the contrary, were complicated by elaborately-folded plates of enamel. Fam. 3. Tapiride.—tThe Tapirs (Tapirus) are characterised by the possession of a short movable proboscis or trunk. The skull (fig. 631) is pyramidal, like that of the pigs, and Z HE NSS AVA Uy fi Nar a J {- , ~~ RRM LPO N : (7 NE \ \e = fay ol Ay ra } Fig. 631.—Side view of the skull of the living Tapirus Americanus. (After Giebel.) the nasal bones project over the nasal cavity. The skin is hairy and thick. The tail is extremely short. The fore- 330 ORDERS OF MAMMALITA. feet (fig. 624, a) have fowr toes each, but these are unsym- metrical (the little toe being smaller than the rest, and not touching the ground), and the hind-feet have only three toes, all encased in hoofs. The dental formula is— The canines do not form projecting tusks, and the molars and premolars are of the “ bilophodont” type, the crown of each presenting two transverse or oblique ridges, separated by broad and shallow valleys. The living species of Zapirus are found in South America, the Malayan Archipelago, and China; and the genus appears to make its first appearance in the Miocene Tertiary, where it is represented by forms hike the 7. Powrieri and T. priscus of Europe. In the European Pliocene we have the well-known 7. Arvernensis ; and in the Post-Plocene of North America the genus is widely distributed. At the present day the genus Zapirus is the sole surviv- ing member of the Tapirida, but we have an extensive series of Tertiary genera, commencing as early as the Eocene. One of the most important of these is the genus Lophiodon, of the Eocene of Europe, which appears to have closely resembled the Tapirs in most respects, but to have possessed some peculiar dental characters. The molars are of the “ bilopho- dont” type (fig. 632, A), each exhibiting two oblique ridges, separated by anterior and posterior valleys or sinuses; and the premolars have the same general character, but want the posterior ridge. The molars are thus of essentially the same type as those of Zapirus, but there 1s now one pre- molar less on each side of the upper jaw, the dental formula being— ) 1—1 ——-s oo Seen mmm eee es ll oo csi > 3—3d The limbs of Zophiodon are still unknown, but such portions of the skeleton as have been discovered are distinctly Tapiroid in character. The genus has not yet been satisfactorily PERISSODACTYLA. oll identified in the New World, but it abounded in Europe during the Eocene period, the species varying from the size of a hare to that of a Rhinoceros. Closely allied to one another, or absolutely identical, are the forms which have been described under the names of Hyracotheriwm, Pachy- nolophus, Pliolophus, Lophiothervum, and Propaleotherium. These are Tapiroid genera from the Eocene Tertiary of the European area, in which the transverse ridges of the molars become broken up into transversely-arranged tubercles. In the Eocene of North America the place of Lophiodon and its European allies seems to be taken by Helaletes and Hyrachyus (fig. 632, B). The latter is strongly Tapiroid in Fig. 632.—a, The three molars and hindmost premolar of the upper jaw on the right side of Lophiodon Isselense, showing the grinding surfaces, Eocene (after Gervais) ; B, Trit- urating surfaces of the molars aud premolars of Hyrachyus agrarius, Eocene of North America (after Leidy). its general characters, having four premolars in the upper jaw on each side (as in Zapirus), and either three or four lower premolars. The premolars, too, resemble those of Lophiodon in being less complex than the molars. In the Miocene of North America few remains of Zapiride have been discovered, and those that are known appear to belong to the genus Zapiravus. We may also provisionally place here a group of American Eocene Mammals (the ZLimnohyide of Professor Marsh), which are in many respects allied to the Tapirs, but are at Jae ORDERS OF MAMMALIA. the same time so closely related to the Paleotheride, that, in the present state of our knowledge, they might be included with equal propriety in either family. The chief genus in this group is Palwosyops, in which the teeth form an almost continuous series, and the dental formula was— The molars are of the Palotheroid type; but the canines were very large and pointed, and resembled those of the Carnivora. Limnohyus, also from the Eocene, dif- fers from the preceding only in the pattern of the molar teeth. The Eocene Diplacodon, lastly, resembles the pre- ceding in many points, but, though hornless, shows points of relationship to the Drontotheride. Fam. 4. Brontotheride,— We may provisionally place here the large fossil Mammals from the Miocene of North America, which Professor Marsh has described under the name of Brontotheride. In these, the fore-feet have four Fig. 633.—Skull of Brontotheriwm ingens. (After Marsh.) nearly equal toes, and the hind-feet three, thus numerically resembling the feet of the Tapirs, but the third digit of the fore-foot has not the pre-eminent development that it has in the latter. In size and in the conformation of the skeleton, the Brontotheride resemble the Elephants, but the limbs are much shorter, and the tail seems to have been long; and though the nose was probably long and flexible, there does not appear to have been any true proboscis. The skull PERISSODACTYLA. aoo was elongated, and the brain-cavity was very small, the cerebral hemispheres not extending over the cerebellum, and little or not at all over the olfactory lobes. ‘There is a pair of large bony protuberances or horn-cores placed sym- metrically and transversely upon the maxillary bones in both sexes. The nasal bones are elongated, and overhang the nasal cavity. The dental formula in Brontotheriwm is— oe ea Bs AC gees 4) 5 6 5 pm : a Dee a 3 = 38. 3—3 3 The incisors are small; and the canines are short and not separated from the premolars by any diastema, these latter being much smaller than the molars. The premolars show two external connate cusps and two closely-united internal cones, and the upper molars have an essentially similar structure, while the lower molars are of the Paleo- therian type. The chief genus is Brontotheriwm, with which the Symborodon and Miobasileus of Professor Cope are more or less entirely synonymous. The genera Titanothervum, Megacerops, and Diconodon also belong to this group. Fam. 5. Paleotheride.—This family comprises a number of remarkable Eocene and Miocene Mammals, which are related closely to both the Tapirs and the Aguide. The type-genus is Palwotheriwm itself, which abounded under various specific forms in the European area during the earlier portion of the Tertiary period. The Palwotheria possessed feet very much like those of the Tapirs, but there were only three digits to both fore-feet and hind-feet. The skull is also Tapiroid in its character, especially in the prominence of the nasal bones, from which it is deduced with great probability that the nose possessed a short mov- able proboscis. The general form also may be supposed to have been like that of the Tapirs, and the restoration of Paleotherium magnum given by Cuvier (fig. 634) exhibits 1 American paleontologists are by no means agreed as to the number of generic types in the Brontotheride, or even as to the names of these. As it is quite impossible for the author to decide this question on its merits, he has adopted the names used by Marsh, who has most fully elucidated the group. 334 ORDERS OF MAMMALIA. to us an animal closely similar to the existing American Tapir. In this particular instance, however, we know that the restoration is incorrect, since the discovery of a com- plete specimen of this species has shown that it was a slender, graceful, and long-necked animal, resembling in its general figure a Llama or certain of the Antelopes. Fig. 634.—Outline of Palwotherium magnum, restored, after Cuvier. Upper Eocene. As regards its dentition, the genus Palw@otherium pos- sessed a complete series of teeth, almost continuously placed, the canines not being excessively developed. The dental formula is— 3—3 1—1 4—4 3—9d (6 em > m —— =44, 3—3 1—1 4—4 3I—9 The molars and premolars (fig. 635) resemble those of the Rhinoceros in many points, but the lower molars have Fig. 635.—Grinding surface of the molar teeth of the upper jaw of Palcwotheriwin crassum, One-half the natural size. (After Owen.) a cistinctly doubly -crescentic form. All the premolars, except the first, resemble the molars in structure. On the other hand, in the genus Palaplotherium, abundantly PERISSODACTYLA. is) Ot represented in the Eocene Tertiary, while the general structure was precisely that of Palwotherium, the premolars exhibit a simpler type of structure than the true molars, while the first premolar is absent. Through Anchithertum the Paleotheride are brought so close to the Hquide, that it seems probable that the two possessed a common origin. Fam. 6. Macrauchenide.—It seems necessary in the mean- while to establish a separate family for the reception of the curious but still imperfectly known Mammals which con- stitute the genus Macrauchenia, the remains of which have been discovered in the Phocene or Post-Pliocene deposits of the South American continent. Owing to the fact that the transverse processes of the cervical vertebra are without a foramen for the passage of the vertebral artery, this anom- alous genus was originally referred to the Camelidw, and named accordingly. It is quite certain, however, that the genus must be placed among the Perissodactyles, as all the feet are three-toed, there is a third trochanter to the femur, and the astragalus resembles that of the Odd-toed Ungulates in having no articular facet for the cuboid bone. The dental formula 1is— 35 1—1 5—5 3—3 1 3 € pie Sh AG, 3—d 1—1 4.—4 3—5 The teeth form a nearly continuous series ; the canines are not excessively developed; the incisors have a deep coronal pit (as in Hquus); and the lower molars resemble those of Paleotherium in being doubly crescentic. The general form of the skull resembles that of the Horses. Fam. 7. Equide (Solidungula ox Solipedia)—This family comprises only the existing Horses, Asses, and Zebras, usually comprised in the single genus Equus; but along with these we must place a large number of extinct forms, in many cases of an extremely interesting character. In all the recent forms, one of the most striking features is the reduction of the digits to a single perfect toe (the third) on each foot; but this character is not available in character- ising the family, since various fossil types show an increase 336 ORDERS OF MAMMALIA. in the number of the digits. In all, however, the third digit is pre-eminently and symmetrically developed, and the foot is distinctly of the Perissodactyle type, while the femur has a third trochanter. There is a discontinuous series of teeth in each jaw-—the premolars being always separated by a wide diastema (fig. 636) from the teeth in front of them—and canines are usually present in the males only. The dental formula is— at =4(). 2) I—o ye ee a hes lade (=) pa S=8 ; P ( ); pm The incisors are of moderate and equal size in both jaws, and typically (Zquus and Hipparion) exhibit a deep pit in their crowns; the canines of the males are usually well developed, but not tusk-like; and the molars are extremely long. The outer side of the molars is deeply grooved with Fig. 636.—Skull of the Horse (Equus cuballus). two parallel grooves, the outer wall being thus doubly crescentic in transverse section, while there are two internal ridges corresponding with the external crescents. The val- leys separating the crescents are filled up with cement, with which the external surface is also coated. The lower molars are doubly crescentic, and present resemblances to the cor- responding teeth in the Palewotheria. As regards the range of the Hguide in time, the earliest PERISSODACTYLA. 33% known members of this family appear at the commencement of the Eocene period in North America, and in the Middle and Upper Eocene in Europe. These old types are, how- ever, widely removed in some respects from the modern Horses, and the genus Agwus itself does not appear till the late Miocene or Lower Pliocene be reached. It is in the North American continent that we find the most complete and instructive series of fossil Eqguidw ; though no Horses existed in the New World at the time of its discovery by the Spaniards. It is in the fossil forms of this region, also, that we can trace most clearly the line of connected forms through which we may suppose Lquwus itself to have descended—our knowledge on this subject having been largely increased by the discoveries of Professor Marsh. Many of the fossil Hquide are still only very partially known, and it will be sufficient here to glance at the more important and better understood types alone. The most ancient member of the guide at present known is the ZHohippus, discovered in the Lower Eocene of New Mexico by Marsh. There is a complete series of teeth, the dental formula being— sais breed hha WA site ois Sm ear ne” gela The last premolar resembles the premolar in front of it, instead of the molar behind it. The animals comprised in this genus were of small size,—the fore-feet possessing four toes, with a rudimentary thumb in addition; while the hind-feet have only three toes, all the digits terminating in hoofs. In beds slightly higher than those with Hohippus are found the remains of Ovohippus. This genus comprises small Equine animals, nearly allied to the preceding, and about as large as Foxes. The fore-feet (fig. 637, A) are four-toed, the third digit being the largest; and the hind- feet are three-toed. There is now no trace of the rudimen- tary pollex of Hohippus; and the last premolar resembles the molars. The dental formula is the same as in Lohippus, and the canines are large and separated from the premolars VOL] I: YY 338 ORDERS OF MAMMALIA. by a long diastema. There is no antorbital fossa, such as exists in Anchitheriwm. In the Lower Miocene of North America we meet with the genus Mesohippus, the species of which are about as large as a sheep, but with longer legs. The hind-feet are three-toed, as are the fore-feet also, but the latter possess a “splint-bone” (rudimentary metacarpal) representing the little finger. Two of the premolars now entirely resemble the molars. In the Upper Miocene of North America Mesohippus is replaced by Miohippus, the animals comprised in which are Fig. 637.—Skeleton of the foot in various forms belonging to the family of the Equide. A, Foot of Orohippus, Eocene ; B, Foot of Anchitherium, Upper Eocene and Lower Miocene ; c, Foot of Hipparion, Upper Miocene and Pliocene; p, Foot of Horse (Equus), Pliocene and Recent. The figures indicate the numbers of the digits in the typical five-fingered hand of Mammals. (After Marsh.) rather larger than a sheep. This genus is intermediate between Orohippus and Anchitherium, differing from the former in the fact that there are only three digits to the fore-feet, and from the latter in having no antorbital fossa. All the feet are tridactylous, the toes being nearly of equal size; and the little finger of the hand—functionally de- veloped in Ovohippus—is here represented by a “ splint- bone.” Allied to the preceding is the genus Anchitheriwm, of the European Miocene, in which the species were about as big as a sheep. In many points this genus exhibits Paleotheroid characters, so that it is transitional between the Lyuwide and PERISSODACTYLA. 339 Palewotheride. Both the hind and fore feet (fig. 637, B) are three-toed, all the toes being sufficiently developed to touch the ground, but the central toe (third digit) is much the largest. There is likewise no splint-bone representing the fifth digit in the hand; while the genus further differs from Miohippus in having a large antorbital fossa. Another important European type of Eqwide is Hipparion, which seems to have abounded in Southern Europe during the later Miocene and Pliocene periods. In this genus, the skeleton is like that of the Horse in its general conformation ; but the feet, though functionally single-toed, are anatomically three-toed. The central toe (third digit) is now the only toe which touches the ground (fig. 637,c); while the second and fourth digits, though visible externally and furnished with small hoofs, are so much reduced in size as to have taken no part in supporting the weight of the body. The teeth are very horse-like, but an antorbital fossa was present. In the Lower Phocene of North America, the place of Hipparion is taken by Protohippus, some of the species of which equalled the Ass in size, while the structure of the feet resembled that of Hipparion. Of the other Pliocene horses of America, the only one of importance is Pliohippus, in which the foot has the same structure as in Hguwus (fig. 637, D). That is to say, the feet have only a single functional toe each, and the second and fourth toes are only represented by rudimentary “ splint- bones,” concealed beneath the skin. Though agreeing with ELquus in the structure of its feet, Pliohippus differs from this genus in possessing a large antorbital fossa, and in having an additional permanent upper preemolar, the dental formula being — 3—3 1—1 4—4 3—3 =, Hii, == Si, = 3—3 1— 3—39 3—3 Lastly, the genus Zywus itself seems to have made ifs first appearance towards the close of the Miocene or the com- mencement of the Pliocene period. In the Old World the first appearance of true Horses seems to be in the Hquus 340 ORDERS OF MAMMALIA. Sivalensis of the Siwalik Hills, in deposits which are usually regarded as of Upper Miocene age, though there is good reason for rather regarding them as belonging to the Plio- cene. In the Pliocene of Europe, North America, and South America, the genus is well represented; and the Equus fossilis of the Post-Pliocene and Recent periods is specifically undistinguishable from the existing Hquus caballus. 341 CHAR ke UT UNGULATA (Continued). ARTIODACTYLA. SecTION B. ArTIopAcTYLA.—In this section of the Unegu- lates the number of the toes is even—either two or fowr—and the third toe on each foot forms a symmetrical pair with the fourth (fig. 624, c). The dorso-lumbar vertebre are nineteen in number, and there is no third trochanter on the femur. If true horns are present, these are always im pairs, and are sup- ported by bony horn-cores. The antlers of the Deer are also parred, but they are not to be regarded as true horns. The stom- ach is always more or less complex, or is divided into separate compartments, and the cecum is comparatively small and simple. By Kowalewsky the Artiodactyla, recent and extinct, are divided into two great groups or sections, in accordance with the nature of the molars. In the one section (Selenodonta) the teeth are crescentic, as in the hving Ruminants and the extinct Anoplotheride. In the second group (Lunodonta) are the living Hippopotamide and Suida, in which the teeth have tuberculated crowns. The section Artiodactyla comprises the Hippopotamus, the Pigs, and the whole group of the Ruminants, including Oxen, Sheep, Goats, Antelopes, Camels, Llamas, Giraffes, Deer, &c. Besides these there is an extensive series of fossil forms commencing in the Eocene or Lower Tertiary period, and in many respects filling up the gaps between the lvine forms. 342 UNGULATA. OMNIVORA. Fam. 1. Hippopotamide.—tThis group contains only the single well-marked genus Hippopotanvus, characterised by the Fig. 688.—Skull of Hippopotumus amphibius, side view. (After Giebel.) massive heavy body, the short blunt muzzle, the large head, and the presence of teeth of three kinds in both jaws (fig. 2—-2 638). The incisors are , the canines extremely large, pte) b oa i—1 and the molars ‘—! oy Dare with crowns adapted aa 7—T 6—6 for grinding vegetable substances. The upper canines are comparatively short, but the lower canines are in the form of enormous tusks, with a chisel-shaped edge. The feet are massive, and are terminated by four hoofed toes each. The eyes and ears are small, and the skin is extremely thick, and is furnished with few hairs. The tail is very short. The molar teeth in the Hippopotamus are of the bunodont type, their crowns being tuberculated, and wearing down with use so as to produce a characteristic double trefoil pattern (fig. 639). The number of incisors varies, as regards the lower jaw. In the living forms, Hippopotamus amphibius has four lower incisors, and belongs, therefore, to a sub- generic group, which includes also most of the fossil forms, and which has been called Tetraprotodon. The only other liv- ing member of the family is the small Liberian Hippopotamus, OMNIVORA. 343 which has only two lower incisors, and which is, therefore, often placed in a separate genus under the name of Chwropsis. Lastly, we have a series of forms from the Upper Miocene of India, which have been raised to the rank of a sub-genus (Hexaprotodon), upon the ground that the lower jaw has six incisors (fig. 640, ¢). So far as at present known, the genus Hippopotamus is an exclusively Old World type, no member of the group having hitherto been detected in the F tarsus rairaeinenne Tertiary of the American continent. Hippopotamus, two-thirds The earliest forms of the genus belong Simms co) fo) to the section Hexaprotodon, and are found in the Upper Miocene deposits of the Siwalik Hills in India. In the later Tertiaries of Europe several species Fig. 640.—a, Skull of Hippopotamus Sivalensis, viewed from below, one-eighth of the natural size; b, Molar tooth of the same, showing the surface of the crown, one-half of the natural size ; c, Front of the lower jaw of the same, showing the six incisors and the tusk-like canines, one-eighth of the natural size. Upper Miocene, Siwalik Hills. (After Falconer and Cautley.) of Hippopotamus are known, of which the most important is the Hippopotumus major of the Pliocene and Post-Plocene. 344 UNGULATA. This well-known species is very nearly allied to the living Hf. amphibius of Africa, and it at one time extended its range over the whole of the south of Europe, and abounded in Britain. By some paleontologists the genus Merycopotamus, of the Upper Miocene of the Siwalik Hills, is referred to the Hip- popotamide, and it certainly has strong affinities with this family. On the other hand, its molars exhibit selenodont characters, which would ally it with the Ruminants, while it has other characters which bring it very close to Anthra- cotherium among the Suida. Fam. 2. Suida.—The group of the Suida, comprising the Pigs, Hogs, and Peccaries, is very closely allied to the pre- ceding; but the feet (fig 624) have only two functional toes, the other two toes being much shorter, and hardly touch- ing the ground. All the three kinds of teeth are present, but they vary a good deal. The canines (fig. 641) typically o Fig. 641.—Skull of the Wild Boar (Sus scrofu ferus). (After Gray.) are very large, and in the males they usually constitute formidable tusks projecting from the sides of the mouth. The incisors are variable, but the lower ones are always inclined forwards. The molars and premolars are typically ; 6—6 7—7 s1x or seven on each side of the mouth Oe) and have tuberculate crowns. The stomach is mostly slightly divided, and is not nearly so complex as in the Ruminants. OMNIVORA. oA De The snout is truncated and cylindrical, fitted for turning up the ground, and is capable of considerable movement. The skin is more or less abundantly covered with hair, and the tail is very short, or represented only by a tubercle. As represented at the present day, the family Swida is a very well-marked and distinctly circumscribed group of Artiodactyles ; but we meet with a large number of extinct types, commencing in the Eocene Tertiary, which show more or less generalised characters, and render it difficult or im- possible, in the present state of our knowledge, to sharply separate off the family from the Hippopotamide on the one hand, and the Anoplotheride on the other. There are, moreover, extinct types with many Suilline affinities, which show points of resemblance to the Ruminants; and. there are others which it may be best to place provisionally in separate groups. The genus Sus, comprising the lving Wild Boar and domestic Pig (Sus scrofa), may be taken as the type of the family ; and its permanent dental formula is— . 3—3 1—1 3—9 3—d a 20 5; pm Si) = 40. 3—d 1—1 3—3 3—3 The lower incisors are inclined forwards (fig. 641); the canines of the males are tusk-like; and the molars have broad crowns, with two transverse ridges (three or more in number in the last molar), which are divided into rounded tubercles. In the Peccaries (Dicotyles), the leading Suilline type of the New World, the incisors are reduced to four in number in the upper jaw; and the molars, though still distinctly of the bunodont type, present more conspicuous transverse ridges, which are less markedly tuberculated than in Sus (fig. 642). On the other hand, in some of the older Tertiary Swida we find that the molar teeth exhibit char- acters intermediate between the bunodont and selenodont types, thus leading us through the family of the Oreodonts to the true Ruminants. In the genus Sus there are four toes to all the feet, but the third and fourth digits form a functionally developed and symmetrical pair, while the second and fifth digits are 346 UNGULATA. rudimentary and do not touch the ground (fig. 624). In the living Peccaries (Dicotyles), again, the fore-feet are the same as in Sus; but the hind-feet become unsymmetrical by the reduction of the fifth digit to its metatarsal. In the Miocene lotheriwm the digits on each foot are reduced to the third and fourth, the second and fifth being present only Fig. 642.—Grinding surface of the molar and premolar teeth of a Peccary (Dicotyles labiatus). (After Giebel.) in the form of rudimentary “ splint-bones,” concealed beneath the skin. Lastly, in many of the older Tertiary Swida there appear to have been four functionally-useful toes to all the feet, the second and fifth digits reaching the ground as well as the third and fourth. The genus Sus itself appears to have commenced in the Miocene Tertiary, with the Sus Lockarti and S. cheroides of the Middle Miocene, and the S. antiquus, S. major, and S. erymanthius of the Upper Miocene. The last mentioned of these is a very large Wild Boar which occurs in the Tertiary deposits of Pikermi in Greece. In the Upper Pliocene of France we meet with the Sus arvernensis, and the living Sus scrofa appears for the first time in the Post-Pliocene deposits of Europe. No species of the genus Sus have as yet been detected in North America. The genera Palwo- cherus and Hyotherium of the European Miocene resemble Sus proper in most respects, but the tubercles of the molar teeth are more distinctly circumscribed. The Miocene Amphichwrus resembled the two genera just mentioned, and differed from Sus in not having the last molar excessively developed, and in the simpler type of the tubercles of the molar teeth; but it possessed extremely long canines, which were directed downwards in the upper jaw. Below the Miocene no Pigs of the modern type have been as yet traced in the European area. The Peccary (Dicotyles), as already mentioned, is the OMNIVORA. 347 typical American Pig; and in glancing at the forms that preceded it in time, we cannot do better than quote the remarks upon this subject made by Professor Marsh. After stating that the oldest Artiodactyle Ungulate as yet known in North America is the Lower Eocene Hohyus, and that this is an ancient representative of the Swida, this distinguished palzontologist proceeds as follows : — “In the beds above, and possibly on the same horizon, the genus Helohyus is not uncommon, and several species are known. The molar teeth of this genus are very similar to those of the Eocene Hyracotherium of Europe, which is supposed to be a Perissodactyle, while Helohyus certainly is not, but apparently a true lineal ancestor of the existing Pigs. In every vigorous primitive type which was destined to survive many geological changes, there seems to have been a tendency to throw off lateral branches, which became highly specialised and soon died out, because they were un- able to adapt themselves to new conditions. The narrow path of the persistent Suilline type, throughout the whole Tertiary, is strewn with the remains of such ambitious off- shoots; while the typical Pig, with an obstinacy never lost, has held on in spite of catastrophes and evolution, and still lives in America to-day. In the Lower Eocene we have the genus Parahyus, apparently one of these short - lived specialised branches. It attained a much greater size than the true lineal forms, and the number of its teeth was much reduced. In the Dinoceras beds, or Middle Eocene, we have . still, on or near the true line, Helohyus, which is the last of the series known from the American Eocene. All these early Suillines, with the possible exception of Parahyus, ap- pear to have had at least four toes, all of usable size. “In the Lower Miocene, we find the genus Percherus, seemingly a true Suilline, and with it remains of a larger form, Elotherium, are abundant. The latter genus occurs in Europe on nearly the same horizon, and the specimens known from each continent agree closely in general characters. The 1 Introduction and Succession of Vertebrate Life in America. An Address delivered before the American Association for the Advancement of Science : 1877. 348 UNGULATA. name Pelonax has been applied erroneously to some of the American forms; but the specimens on which it was based clearly belong to Elotheriuwm. This genus affords another example of the aberrant Suilline offshoots, already mentioned. Some of the species were nearly as large as a Rhinoceros, and in all there were but two serviceable toes, the outer digits, seen in living animals of this group, being represented only by small rudiments concealed beneath the skin. In the Upper Miocene of Oregon, Suillines are abundant, and almost all belong to the genus 7hinohyus, a near ally of the modern Peccary (Dicotyles), but having a greater number of teeth, and a few other distinguishing characters. In the Phocene, Suillines are still numerous, and all the American forms yet discovered are closely related to Dicotyles. The genus Platygonus is represented by several species, one of which was very abundant in the Post-Tertiary of North America, and is apparently the last example of a side branch before the American Suillines culminate in the existing Peccaries. The feet in this species are more specialised than in the living forms, and approach some of the peculiar features of the Ruminants; as, for example, a strong tend- ency to coalesce in the metapodial bones. The genus Platy- gonus became extinct in the Post-Tertiary, and the later and existing species are all true Peccaries.” Leaving the typical Suida, we must next glance at a group, or several groups, of Tertiary Mammals, which have strong Suilline affinities, but which have a more or less distinctly selenodont type of dentition, though in a generalised form, and which thus conduct us from the Suida to the true Ruminants. Among the more pig-lke of these transitional forms Anthracotherium and Cheropotamus may be specially singled out. In Anthracotherium are included a number of Miocene Swillines—all European—in which the dentition is complete, the incisors being strong, the canines moderately large, and the molars (fig. 643, A) having the two transverse lobes which characterise their crowns broken up into four tubercles, while the last molar has an accessory fifth tubercle. The Cheropotamus of the Eocene Tertiary shows points of resem- OMNIVORA. 349 blance to the modern Peccary, as well as to Anthracotherium. The dental formula is— .3—3 I1—1 4-4 FG, t Be 5 MD = ; m =42 3—3 1—1 3— 3—3 There is thus a premolar less in the lower jaw than in the preceding genus. The canines are of small size; the molars have four principal tubercles, the last lower molar having two additional accessory tubercles ; and the pattern of the premolars is simpler than that of the molars. Fig. 648.—a, Grinding surfaces of the last two upper molars on the left side of Anthraco- therium magnum—Miocene (after Gervais); 8, First two upper molars on the left side of Hyopotamus porcinus, viewed from above—Hocene (after Gervais); c, Grinding surface of an upper molar of Anoplotherium commune— Eocene (after Owen) ; Dp, Last three upper molars of Dichodon cuspidatus, viewed from above—Eocene (after Owen); £, Grinding surface of an upper molar of the same ; F, The five last upper molars on the left side of Xiphodon gracile, viewed from above—Eocene (after Gervais); G, The three last left molars of Dichobune leporinum—Kocene (after Fraas). The genus Hyopotamus, of the Eocene and Lower Miocene, is regarded by Kowalewsky as the type of a distinct fam- ily (the Hyopotamide) ; but it undoubtedly possesses close affinities with the genera just noticed. The dentition is complete, and of a generalised selenodont type; the molars (fic. 643, B) terminating in pyramidal lobes, the summits of which are moderately sharp, and the valleys between which are not filled in with cement. The crowns of the lower molars exhibit double crescents, with an internal tubercle ; and the upper molars possess an accessory fifth lobe. The 350 UNGULATA. feet are typically tetradactyle, the lateral toes being well developed; but in some forms (Diplopus) the second and fifth digits are wanting, and the foot is two-toed. We have next a group of small Eocene and Miocene Mammals (the Aiphodontide), which have affinities with the preceding forms, and also with the following group of the Anoplotheride (especially to Dichobune and Dichodon) ; but which likewise exlubit relationships with the Ruminant group of the Zragulide (Chevrotains). The genus Xiphodon itself comprises small Artiodactyle Mammals, with didactyle feet, a short tail, and long and slender hmbs. The déntition is complete, the teeth forming a continuous series in both jaws, and the canines being of small size. The molars (fig. 643, F) are of a generalised selenodont type, the lower ones, having “two pairs of crescentic lobes with the convex- ities turned outwards” (Owen). Cainotheriwm includes small Eocene and Miocene Mammals, also nearly allied to the Tragulide, which resemble the preceding in most respects, but have the lateral toes developed on all the feet. Miero- therium, of the Miocene Tertiary of Europe, is also very near to the true Chevrotains, but it differed from these, and agreed with the preceding genera, in having a complete dentition, the dental formula being— 9 a / » ae) jp i Ae o a ig ES i) GY) A 3—39 1 — 4—_4 3—3 The upper molar teeth have three posterior cusps and two anterior, as in Cainotherium and Dichobune. The presence of this additional posterior cusp in the upper molars is a character shared also by the interesting Homacodon of the Upper Eocene of North America, which has a generalised selenodont dentition, though in other respects allied to the Suida. Fam. 3. Anoplotheride.—We come next to the family of the Anoplotheridew, which, in the present state of our know- ledge, can with difficulty be limited precisely, or sharply separated from some of the groups just noticed. The type of this group is Anoplotherium itself, of which there are two or three species known from the Upper Eocene of Europe. OMNIVORA. Saya The body in this genus (fig. 644) was slender, the size being about that of the existing Ass, and there was a long tail, the vertebree of which carried chevron-bones below. The Fig. 644.—Anoplotherium commune. Eocene ‘lertiary. feet are typically didactyle, no accessory toes being developed, and the metapodials being separate. The dentition is com- plete, the teeth forming an uninterrupted and continuous series, the crowns being nearly on the same level, and there being no diastema between the canines and the premolars. The dental formula is— . 3—3 1—1 4—4 3—3 0 Ce Oe TE - = 44. 3—3 1—1 4—4 3I—9 The molar teeth in some respects resemble those of the Rhinoceros, and exhibit generalised selenodont characters. The upper molars (fig. 643, c) have quadrate crowns, divided into two principal lobes, an anterior and posterior, which in turn are less conspicuously bisected by a fore-and-aft depression. The wide valley separating the anterior from the posterior lobe is distinguished by the presence of a large accessory lobe or tubercle at its wide inner entrance. The Miocene genus Chalicotherium, which has been shown to occur in North America, China, India, and Europe, is usnally placed close to Anoplotherium ; but it seems questionable if it should not rather be referred to the Perissodactyla, and regarded as an ally of the Zapiride or Brontotheride. It comprises species as large as the existing Rhinoceroses. Eurytherium, also, though with a dentition nearly the same Soe UNGULATA. as that of Anoplotherium, is stated to have tridactyle feet, and would thus seem to belong to the Perissodactyle section of the Ungulates. Of the other Anoplotheroid genera, we need only mention Dichodon and Dichobune, both of which have marked rela- tions with the Yiphodontidw, and through these with the Ruminant group of the Chevrotains (7ragulide). The genus Dichobune, in particular, is nearly allied to Xiphedon, the premolars being elongated from before backwards, and, ex- cept the last, sub-trenchant. There is, however, a slight gap between the canines and premolars. The genus is from the Eocene of Europe. In the genus Dichodon, also from the Eocene, the dentition is likewise complete, and the molars (fig. 643, D and E) have four-lobed crowns, the cusps of which are sharp and conical, while the canines are small, and differ little in size and form from the incisors. Fam. 4. Oreodontide.—tThe last of these transitional groups of Artiodactyles which requires notice is that of the Oreo- dontide, comprising a number of curious Uneulates from the Miocene and Phlocene Tertiary of North America, which stand midway between the Swida and the Rwininantia, and have therefore been appropriately. termed “ruminating hogs” by Leidy, though we have no actual evidence to show that they really “ruminated.”, In Oreodon, the type of the eroup, we have an even-toed Ungulate, in size about equal to the Sheep, and with characters allying it to the Swida on the one hand, and the Deer on the other. The feet were tetradactylous, and the metacarpals and metatarsals were not anchylosed. The dentition is complete, the dental formula bemg— 9 » » » . 33 1—1 4—4 3—3 0D oC 5 piv ; Mm — 44. 3—3 1—1 4+—4 3—3 The incisors are of small size; and the canines are large, trihedral and worn like those of the Pig, and separated by a diastema from the premolars. The premolars and molars, on the other hand, are of the Ruminant type, the former exhibiting one crescent, and the latter having the regular doubly-crescentic form of the typical Selenodont Artiodac- RUMINANTIA. oboe tyles (fig. 645). There is also the anomalous character that “Jarmiers ” or “ tear-pits”’ existed below the orbits, as in the Cervide. Oreodon itself is a Miocene genus, as is the much larger Eporeodon. In the Middle Miocene we have the Oreodont genus Agriochwrus, which has strong relationships Fig. 645.—Grinding surface of the upper molars and premolars on the right side of Oreodon major. Miocene, North America. (After Leidy.) with the Hyopotamus of the European Eocene; and the family is continued into the Pliocene by the genera Mery- chyus and Merycocherus, after which it disappears altogether. RUMINANTIA. The last section of the Artiodactyle Ungulates is the great and natural group of the Ruminantia, or Ruminant animals. This section comprises the Oxen, Sheep, Antelopes, Giraffes, Deer, Camels, &c., and is distinguished by the following characters :— The foot is what is called “cloven,” consisting of a sym- metrical pair of toes encased in hoofs, and looking*as if pro- duced by the splitting into two equal parts of a single hoof. In addition to these functional toes, there are usually two smaller lateral digits placed at the back of the foot. The metacarpal bones of the two functional toes of the fore- limb, and the metatarsal bones of the same toes of the hind- limb (except in Hyomoschus), coalesce to form a single bone, known as the “canon-bone.”’ The stomach is complex, and is divided into several compartments, this being in accord- ance with their mode of eating. They all, namely, ruminate or “chew the cud’”—that is to say, they first swallow their food in an unmasticated or partially-masticated condition, and then bring it up again, after a longer or shorter time, in order to chew it thoroughly. : VOLS te: Z 354 UNGULATA. The dentition of the Ruminants presents peculiarities almost as great and as distinctive as those to be derived from the di- gestive system. In the typical Ruminants (e.g., Oxen, Sheep, Antelopes), there are no incisor teeth in the upper jaw, their place being taken by a callous pad of hardened gum, against which the lower incisors impinge (fig. 646). There are also wie Fig. 646.—Skull of a hornless Sheep (after Owen). i, Incisors ; ¢, Canines ; m, Molars and premolars. no upper canine teeth, and the only teeth in the upper jaw are six molars on each side. In the front of the lower jaw is a continuous and uninterrupted series of eight teeth, of which the central six are incisors, and the two outer ones are regarded by Owen as being canines. Upon this view, canine teeth are present in the lower jaw of the typical Ruminants, and they are only remarkable for being placed in the same series as the incisors, which they altogether re- semble in shape, size, and direction. Behind this continuous series of eight teeth in the lower jaw there is a vacant space, which is followed behind by six grinders on each side. The premolars and molars are of the “selenodont ” type, and have their grinding-surfaces marked with two double cres- cents, the convexities of which are turned inwards in the upper, and outwards in the lower teeth. PSS) or Ot RUMINANTIA. The dental formula, then, for a typical Ruminant animal, 1s— _0—0 0—0 3—3 3—9d a Ea 5 pm Pei = B75 3—3 1—l1 3—3 3—3 The departures from this typical formula occur in the Cam- elide, the Tragulide, and in some of the Deer. Most of the Deer conform in their dentition to the above formula, but a few forms (e.g., the Muntjak) have canine teeth in the upper jaw. These upper canines, however, are mostly confined to the males; and if they occur in the females, they are of a small size. The dentition of the Camelide (Camels and Llamas) is still more aberrant, there being two canine-like upper incisors and upper canines as well. The lower canines also are more pointed and stand more erect than the lower incisors, and slightly separated from them, so that they are easily recognisable. The group of the Ruminantia includes the families of the Camelidw (Camels and Llamas), the 77ra- gulide (Chevrotains), the Cervide (Deer), the Camelopardalida (Giraffe), and the Cavicornia (Oxen, Sheep, Goats, Antelopes). a. Camelide (Tylopoda).—The Camels and Llamas consti- tute in many respects an aberrant group of the Ruminantia, especially as regards their dentition and the conformation of the feet. The upper jaw (fig. 647) carries, in the living Fig. 647.—Side view of skull of Camelus Bactrianus. 1, Upper incisor; ¢, c, Canines ; pm, Isolated preemolar. (After Giebel.) forms, three teeth on each side in front, separated by slight intervals. The most anterior of these is a conical incisor ; the central one is a canine, and the hindmost is the first 356 UNGULATA. premolar, which is separated by a wide gap from the rest of the molar series, and is pointed in form. In the lower jaw there is also a canine, placed a little behind the incisors, and a detached laniariform premolar (the latter sometimes absent). In the Llamas these isolated premolars are wanting. In the living Camelide the upper incisors, as we have seen, are re- duced to two in number, but in some of the extinct types of the family (e.g., the Pliocene Protolabis) we find that the series of incisors is complete, being six in number in each jaw. The foot in the Camelide terminates in two toes, furnished with imperfect nail-like hoofs, and the second and fifth toes are wanting. In the Miocene Poébrotherium the metacarpals and metatarsals remain distinct from one another throughout life (as in the living Hyomoschus). Horns are not known to have been developed in any of the Camelidw. The Camelida make their first appearance, so far as known, in the Lower Miocene of North America, where the family is represented by the genera Poébrotherium and Protomeryx, the former of these having the embryonic character, that the metapodials do not coalesce to form a “canon-bone.” In the Old World, on the other hand, the first recorded appearance of the Camelide is in the Siwalik deposits of India, which are generally re- garded as of Upper Miocene age. Here we meet with the existing genus Camelus. In the Pliocene deposits of North America we have a number of extinct types of the Camelide. Of these Procamelus (fig. 648, B and Cc) seems to have re- sembled the true Camels in most respects, and one species was about as large as the existing Camels; but there were four premolars on each side of each jaw, instead of three only. Though characteristically Pliocene, this genus has also been found in the Miocene of North America. Homocaimelus re- sembles the preceding in some respects, but has large canines and isolated first upper premolars; while Merycodus shows some peculiarities in the structure of the molar teeth. In the Phocene of South America we meet with the two extinct generic types Paleolama and Camelotherium ; and the living genus Auchenia, comprising the Llamas and Alpacas, seems to have come into existence at the same time. Remains of RUMINANTIA. 357. Auchenia are also found in the bone-caves of Brazil, and in the Post-Tertiary of North America (fig. 648, A). At the present day the Llamas are exclusively confined to South America, but they seem to have abounded in the Quaternary Fig. 648.—a, First molar of Auchenia hesterna, viewed from above—Quaternary deposits of California ; c, Grinding surface of the last lower molar of Procamelus Virginiensis—Miocene, North America ; B, Grinding surface of the last premolar and first molar of the same. All the figures are of the natural size. (After Leidy.) of North America, and one of the fossil species (Auchenia hesterna) seems to have much exceeded both the living species of the genus in size, and to have been larger than the existing Camels. Lastly, in the Drift-deposits of Siberia (of Post-Pliocene age) are found the molar teeth of an extinct genus of Camelidw, to which the name of Merycotheriwm has been given. b. Tragulide—This group comprises certain small Rumi- nants, the so-called “ Chevrotains” (Zragulus), which have been generally associated with the true Musk-deer (Moschus) in a single family, under the name of Moschide. ‘The re- searches of Milne-Edwards and Flower, however, would prove that Moschus itself is really one of the Cervide or Deer proper, and that the Chevrotains form a group by themselves. The Tragulide are characterised by the total absence of horns in both sexes, and by the presence of canines in both jaws, those in the upper jaw (fig. 649) being in the form of tusks in the males, but much smaller in the females. The third stomach, or “ psalterium,” is wanting, and the placenta is diffuse. The feet have supplementary toes, and the meta- carpals of the middle and ring digits either unite in late life to form a canon-bone, or remain (as in Myomoschus) perma- nently separate. ©o Or oe) UNGULATA. With regard to the structure and precise affinities of most of the fossil forms which have been referred to the Zraguli- de, great uncertainty still obtains, and it is not at present possible to speak very positively as to the precise range of the family in past time. It seems quite possible that the Upper Eocene and Miocene Xiphodon and Cainotherium, as has been previously noticed, are really referable to the Fig. 649.—Side view of the skull of Tragulus Javanicus. (After Giebel.) Tragulide. In the Miocene period in Europe it seems certain that various types of Zragulidew were in existence. Thus the Dremotherium and Amphitragulus of the Miocene are probably true Chevrotains ; and the existing genus Hyo- moschus has been said to occur in deposits of the same age in France. The genus Zvagulus itself has not been dis- covered in the fossil condition, and no remains clearly referable to this family have yet been detected in the Tertiaries of America. c. Cervide—This family is of much greater importance than that of the 7ragulide, including as it does all the true Deer. They are distinguished from the other Ruminants chiefly by the nature of the horns, which are wanting in the Musk-deer (Moschus) and in a few other forms. With the single exception of the Reindeer, these appendages are confined to the males amongst the Cervide, and do not occur in the females. They do not consist, as in the succeeding group, of a hollow sheath of horn surrounding a central bony core, nor are they permanently retained by the animal. On the other hand, the horns—or, as they are more properly called, the antlers — of the Cervide are deciduous, and are solid. Most usually the antlers are RUMINANTIA. 359 cast off once a-year, and are reproduced again, this taking place immediately before the breeding season; but some Indian deer do not throw off their horns so often. In the Middle Miocene Procervulus, moreover, the horns seem to have been persistent throughout life. The antlers of the Cervide are bony throughout, and are produced by a process very similar to that by which injuries of osseous structures are made good in man. Lach antler consists of a main stem or “beam,” and usually of one or more branches or “tynes,’ and when first produced they are covered with a finely-haired and vascular integument. When fully formed there is produced, just above the base of attachment to the frontal bone, a circular ridge of bone, which is known as the “burr;” after which the “ velvet ” or external integument dies and peels off, leaving the antler as a naked process of bone. In the second year after birth in all Deer possessing horns, and in a few forms throughout life, the antlers consist only of the “beam,” and are dagger-shaped and unbranched. In the horns of the next year, we find that the beam develops a basal branch or “ brow-tyne” (fig. 650, c). This condition of matters may be compared with the permanent form of the antler in the Miocene Dicroceros (fig. 650, A), in which there is only a single “ tyne” on the “beam.” In the next year of life—the fourth after birth—ain addition to the “ brow-tyne ” one or more tynes are developed nearer to the free end of the antler; and we may now compare the state of things to what is permanently the condition of the antler in many of the Pliocene Deer (such as Cervus Matheroni and C. pardinensis, fig. 650, B). In succeeding years of life, in many Deer, the antlers become, every time they are repro- duced, more and more complex, by increase in the number of the “tynes,’ and by augmentation of their length and size. Lastly, it may be mentioned that in the singular Asiatic Muntjak (Cervus Muntjak) the antlers exhibit the peculiarity of being supported upon long bony pedicles or processes of the frontal bones (fig. 650, E). As regards the distribution of the Cervidw, no undoubted members of the family are known to have existed during 360 UNGULATA. the Eocene period, though some palzontologists are ‘inclined to think that the hornless Xiphodon of this period may be an early form of the Deer. It is also possible, as suggested by Marsh, that the Oromeryx of the Upper Eocene of North America is an ancestral type of the Cervide. Fig. 650.—a, Antler of Dicroceros anoceros—Miocene Tertiary; B, Antler of Cervus (Ais) pardinensis—Pliocene ; c, Antler of the Red Deer (Cervus elaphus) in the second year; p, Antler of the same in its fully-grown condition; £, Antler and bony pedicle of the frontal bone in the Muntjak (Cervus Muntjak); ¥, Antler of the Fallow Deer (Dama platyceros). In the Miocene deposits of Europe we meet with a number of types of Cervidw, including the recent genus Cervus. Most of the forms of this period, however, are extinct, and belong to the genera Dicroceros and Dorcatherium. In the former of these (fig. 650, A) the antlers appear as if produced by the bifurcation of the “beam ” into two divi- sions. In the Miocene, also, we find the first traces of the true Musk-deer, if Amphimoschus be rightly referred to the Moschide. In the Pliocene period remains of Deer become abundant ; and, according to Professor Boyd-Dawkins, they belong to two principal types, represented respectively by the Roebuck (Capreolus caprea) of Europe and the Axis Deer of Asia, and most of them resembling the latter. None of the Pliocene Deer belong to species now alive. In the Post-Plocene period, we meet with a number of Deer, most of which belong to well-known living types. Of RUMINANTIA. 361 these, the true Elks, represented by the living Moose (Alces malchis, or A. palmatus), are distinguished by their antlers without either basal or mesial “ tynes,” but terminated by a great palmation digitated on its outer side only. Antlers of a species undistinguishable from the existing Moose have been found not uncommonly in Post-Tertiary deposits in various parts of Europe, but this animal does not make its appearance till after the close of the Glacial period. The Reindeer (Cervus tarandus) of Northern Europe and North America is remarkable for being the only member of the Cervide in which both sexes have horns. The horns are of large size, cylindrical, divided, with basilar and median tynes. Remains of the Reindeer are found, often in considerable abundance, in various Post-Pliocene deposits in Europe, extending as far south as the Pyrenees. Intermediate between the Reindeer and the Fallow Deer is the celebrated Post-Pliocene species, which is commonly known as the “Irish Elk” (Cervus megaceros or Megaceros Hibernicus). This extinct form (fig. 651) is remarkable for its great size and for the enormous dimensions of the spread- ing antlers, which are expanded towards their extremities, and attain an expanse of as much as ten feet from tip to tip. The Cervus megaceros is exclusively Post-Tertiary, but does not appear, so far as is known with certainty, to have sur- vived into the Historic period. The true Stags (Cervus), to which the Irish Elk seems properly to belong, are typified by such species as the Red Deer (Cervus elaphus) of Europe, and the Wapiti (Cervus Canadensis) of North America. The former of these occurs in a fossil state in Post-Pliocene and Recent deposits in Europe, and the latter is represented in accumulations of the same age in America by a closely-allied or identical form. Another remarkable type of Stag, now wholly extinct, is the Cervus Sedgwickii of the Norfolk “ Forest-Bed ” (Post-Pli- cene), in which the antlers have a very complicated form. The Roebuck (Capreolus caprea), distinguished by its branched antlers, with a median, but without a basilar, tyne, is also known in a fossil condition in Post-Pliocene deposits in. Europe, appearing before the commencement of the 362 UNGULATA. Glacial period. The form of the horns (fig. 652) is one quite peculiar among the existing Deer, but Cervide with antlers of the Capreoline type have been shown by Boyd- Dawkins to have existed during the Miocene period, so that Fig. 651.—Cervus megaceros (Megaceros Hibernicus), the “ Irish Elk.” Post-Pliocene. this form of antler must be regarded as one of the most ancient at present known to us. In fact, the Miocene genus Dicroceros appears to be an early representative of this type. d. Camelopardalide.—tThis family includes only a single living animal—the Camelopardalis Giraffa, or Giraffe. There are no upper canines in the Giraffe, and both sexes possess two small frontal horns, which, however, are persistent, and 9 2) RUMINANTIA. o00 remain permanently covered by a hairy skin, terminated by a tuft of long stiff bristles. These are not mere out-growths of the frontals, but are independent ossifications placed on the sutures between the frontal and parietal bones. There is also a central horn, if it may be so called, which is of the Fig. 652.—Side view of the skull of the Roebuck (Capreolus caprea). (After Giebel.) nature of an epiphysis, and is placed upon the sagittal suture. It becomes early anchylosed with the skull, as do ultimately the other two horns. The neck is of extra- ordinary length, but, nevertheless, consists of no more than the normal seven cervical vertebra. The fore-legs appear to be much longer than the hind-legs, and all are terminated by two toes each, the lateral toes being altogether wanting. Fossil species of Giraffe (Camelopardalis) have been dis- covered in the Tertiary deposits of the Siwalik Hills in India and in the Upper Miocene of Attica; and a species has also been described from France. This last, however, would seem to be referable to the genus Helladotherium, founded for the reception of some singular fossils from the Upper Miocene Tertiary of Attica. In this remarkable genus there appear to have been no horns, and the teeth present certain resemblances to those of the Antelopes. No member of the Camelopardalide has as yet been discovered in either North or South America, so that this peculiar Ruminant type would appear to be wholly confined to the Old World. e. Cavicornia.—The last family of the Ruminants is that 364 UNGULATA. of the Cavicornia, comprising the Oxen, Sheep, Goats, and Antelopes. This family includes the most typical Rumi- nants, and those of most importance to man. The upper jaw in all the Cavicornia is wholly destitute of incisors and canines, the place of which is taken by the hardened gum, against which the lower incisors bite. There are six in- cisors and two canines in the lower jaw, placed in a con- tinuous series, and the molars are separated by a wide gap from the canines. There are six molars on each side of each jaw. Both sexes have horns, or the males only may be horned, but in either case these appendages are very dif- ferent to the “antlers” of the Cervide. The horns, namely, are persistent, instead of being deciduous, and each consists of a bony process of the frontal bone—or “horn-core ”— covered by a sheath of horn. In the Prong-buck (Antilo- capra), however, the sheath of the horn is shed annually. The feet are cleft, but are mostly furnished with accessory hoofs placed on the back of the foot. The Cavicornia comprise the three families of the Antilo- pide, Ovide, and Bovide. The Antelopes form an extremely large section, with very many species. They are character- ised by their slender, deer-like form, their long and slender legs, and their simple, cylindrical, annulated, or twisted horns, which are sometimes confined to the males, but often occur in the females as well. The above definition will not apply in all points to some singular extinct forms usually referred to the Antilopide, nor to one aberrant existing form—viz., the Prong-buck (Antilope furcifer, or Antilocapra Americana). This extra- ordinary and unique species differs from the typical Ante- lopes in having no lateral toes, in having horns which have a snag in front, and in the fact that the outer sheath of the horn is deciduous, and not permanent. For these reasons, it has been proposed to place the Prong-buck in a separate family (the Antilocapride); but it is more con- venient here to consider it as an aberrant member of the Antilopide. The Antelopes do not appear to have a high antiquity, the oldest known forms being from the Upper Miocene of RUMINANTIA. 365 Greece, and belonging to the living genus Gazella and to various extinct types. Of the latter, the genus Palworeas (fig. 653) is supposed to be allied to the living Eland Fig. 653.—Skull of Palworeas Lindermayeri, without the lower jaw, reduced in size. Upper Miocene. (After Gaudry.) (Oreas canna) of South Africa, in which the horns are nearly straight, but have a spiral twist. Palworyx, again, is supposed to be allied to the living Gemsboks (Oryx) of Africa, and possessed long curved horns, while Palwo- tragus and Tragoceras appear to be true Antelopes, though the iatter possesses very Goat-like horns. No important remains of Antelopes of the ordinary type are known from the Pliocene deposits; but remains of a Chamois (Rupi- capra) have been found in the cave-deposits (Post-Pliocene) of France, and bones of the living genus Axtilope and the extinct genus Leptotherium are said to occur in the bone- caves of Brazil. No North American Antelopes are known as fossils (unless the Phocene Cosoryx be an aberrant type of this family), and there is some doubt as to the reported occurrence of Antilopide in South America. By far the most remarkable fossils, however, which have 366 UNGULATA. generally been referred to the Antilopidw are the Upper Miocene (or Lower Phocene) genera Stvatherium and Lramatherium. Sivatherium (fig. 654) is known by the single species S. giganteum, discovered by Dr Falconer and Sir Proby Cautley in the Tertiary deposits of the Siwalik Hills in India. The Fig. 654.—Skull of Sivatherium gigantewm. Upper Miocene, India. (After Murie.) inmost important peculiarity in Sivatheriwm is the structure of the horns, of which the animal possessed two pairs. Both pairs of horns were supported by bony “ cores,” so that there can be no hesitation in referring Sivatheriwm to the group of the Cavicorma. The anterior horns, as shown by the shape of the horn-cores, were simple; and if the posterior horns had been of a similar form, then Sivatherium might have been fairly regarded as merely a gigantic four-horned Ante- lope, similar to the living Antilope (Tetraceros) quadricornis of India. The posterior horns, however, are not only much larger than the anterior, but they possess two snags or branches—a peculiarity not to be paralleled amongst existing Cavicoriia, except in the Prong-buck. Dr Murie, however, RUMINANTIA. 367 in an admirable paper on the affinities of Swatheriwm, has drawn attention to the fact that the Prong-buck sheds the sheath of its horns annually, and has suggested that this may have also been the case with the extinct form. This hypothesis is rendered probable, amongst other reasons, by the fact that no sheath has as yet been discovered surround- ing the horn-cores of either pair of horns in the Swwatherium. Upon the whole, therefore, the above-mentioned zoologist would refer Sivatheriwm to a distinct group which he terms Swatheride, and regards as being most nearly related to the Antilocapride. Bramatherium has been found in deposits of the same age as Sivatheriwm, with which it agrees in its colossal dimensions and its possession of two pairs of hollow horns. It differs from Stvatheriwn, however, in certain details of minor importance. The Sheep and Goats (Ovidw) have mostly horns in both sexes, and the horns are generally curved, compressed, and turned more or less backwards. The body is heavier, and the legs shorter and stouter, than in the true Antelopes. In the true Goats (Capra) both sexes have horns, and there are no lachrymal sinuses. The true Sheep (Ovis) are destitute of a beard, and the horns are generally twisted into a spiral. Horns may be present in both sexes, or in the males only. The Sheep and Goats are of no importance as fossils, unless, indeed, as believed by high authorities, the Musk-ox should be referred to the Ovidw. Here, however, it will be considered as belonging to the Bovide. Remains of both Sheep and Goats have been discovered in various Post- Tertiary deposits in Europe, but they present nothing of special interest. No remains of Ovidew are known at present from any deposits older than the Post-Pliocene. The true Oxen (Bovidw) are distinguished by having simple horns, of a rounded shape, not twisted into a spiral. The oldest known remains of Oxen, so far as known, are those of the Upper Miocene of India, in which we find various extinct species of the living genus Bos, together with the extinct genera Hemibos and Amphibos. In the Pliocene 268 UNGULATA. of Europe we meet with the genus Bos; and the American Buffalo is represented as early as the Lower Pliocene by a species of Bison. The best known fossil Oxen, however, are those of the Post-Pliocene and Recent periods; and of these the most important are the Uvrus, the Aurochs, the Bos longifrons of Owen, and the Musk-ox (Ovibos). The Aurochs or Lithuanian Bison (Bos bison) can hardly be considered as a fossil form, as it occurs in a living state in Europe at the present day. Remains, however, of this large ox are found in various prehistoric deposits. The Bos longifrons of Owen, or “Small Short-horn,” is in a similar position to the Aurochs. According to Professor Boyd-Dawkins, this form (which is identical with the os Jrontosus of Nilsson) has not been proved to occur in any Post-Pliocene deposit, though it occurs plentifully in the bone-caves and alluvia of the Recent or prehistoric period. It is believed by the same high authority that the Bos longi- Jrons is the ancestor of our present Welsh and Scotch Cattle. The Urus or Wild Bull (Bos primigenius), though much larger than our ordinary oxen, is believed to be specifically Fig. 655.—Skull of the Urus (Los primigenius). Post-Pliocene and Recent. (After Owen.) undistinguishable from the domestic Ox (Bos taurus), and it was probably the parent of the larger varieties of European Oxen. It was a contemporary of the Mammoth, Woolly Rhinoceros, Cave - lion, Cave - bear, Irish Elk, and other RUMINANTIA. 369 Post-Pliocene Mammals, and it was in existence up to at least the twelfth century. The last of the Oxen which deserves notice is the curious Musk-ox (Ovibos moschatus). This singular animal is at the present day a native of Arctic America, and is remarkable for the great length of the hair. It is called the Musk-ox, because it gives out a musky odour. Like the Reindeer, the Musk-ox had formerly a much wider geographical range than it has at present—the conditions of climate which are necessary for its existence having at that time extended over a very much larger area than at present. The Musk- ox, in fact, in Post-Tertiary times is known to have extended over the greater part of Europe, remains of it occurring abundantly in certain of the bone-caves of France. As already mentioned, high authorities regard the Musk-ox as being truly a large Sheep, and as being, therefore, referable to the Ovide. VOL.. II. DRAIN 370 CHAPTER XLIV. ORDERS OF MAMMALIA (Continued). DINOCERATA, TILLODONTIA, AND TOXODONTIA. OrbER VII. Dinocerata.—This order comprises certain extra- ordinary extinct Mammals from the Eocene of North America which are regarded by Professor Cope as an aberrant group ot Ungulates, whilst Professor Marsh considers them as a dis- tinct order intermediate between the Perissodactyle Ungulates and the Proboscidea. The members of this order are all of gigantic dimensions, and of massive construction. oth the fore and hind feet possessed five well-developed toes, each of which terminated im a hoof. The nasal bones were elongated, and do not seem to have supported a proboscis. The cranium carries three parrs of horn- cores, which were probably enveloped in horny sheaths. There are no upper incisors, and the wpper canines have the form of long tusks directed downwards. (These characters are taken from Dinoceras, the best known genus of the group.) The order is distinguished from the Proboscidea by the absence of upper incisors, the presence of canines, the possession of three pairs of horn-cores, and the absence of a proboscis. In Dinoceras itself, which may be taken as the type of the eroup, we have a large animal equal in dimensions to the living Elephants, which it resembles also in the osteology of its limbs, in most essential respects. It is in the skull (fig. 656) and dentition, however, that the most striking peculi- arities of Dinoceras are to be found. As regards the denti- DINOCERATA, TILLODONTIA, AND TOXODONTIA. 371 tion, the front of the upper jaw was destitute of incisors, and probably carried a palatine pad, but there were two very large canines in the form of tusks directed perpendicularly down- Fig. 656.—Skull of Dinoceras mirabile (after Marsh). From the Eocene Tertiary. wards; and there was also a series of six small molars on each side. In the lower jaw are six incisors, small canines, and twelve premolars and molars, six on each side. The dental formula is thus— ; 0—0 1—1 om 3—3 3—3 2 4 pRB EY iG) = Me 3I—3d 1—1 3—3d 3—3 The crowns of the molar teeth exhibit each a pair of oblique ridges, confluent on the inner side of the tooth, but diverging outwardly in a V-like manner. From the very small comparative size of the molars, and the fact that the condyle of the lower jaw is transversely elongated, thus allow- ing only of up-and-down movement, it has been conjectured that the food of Dinoceras must have been of an animal nature. Superiorly each maxillary bone carried a well- developed process, probably of the nature of a horn-core. The nasals support two similar but smaller horn-cores ; and 372 ORDERS OF MAMMALIA. the frontals arg developed behind into two larger bony pro- jections, most probably also of the nature of horn-cores. The animal thus possessed three pairs of horns, one carried by the upper jaw-bones, one by the nasals, and one by the frontal bones. Whether, however, these so-called “ horn-cores” really supported horns, of the nature of the horns of the Cavicorn Ruminants, is quite a matter of conjecture; and there is much probability in the view entertained by Owen— namely, that some of them were simply covered by callous integument. As regards the mental powers of Dinoceras, Professor Marsh remarks: “The brain-cavity of Dinoceras is perhaps the most remarkable feature in this remarkable genus. It proves con- clusively that the brain (fig. 657, A) was proportionately Fig. 657.—a, Skull of Dinoceras, viewed from above, showing the form and size of the brain ; B, Fore-foot of Dinoceras ; c, Hind-foot of Dinoceras. (After Marsh.) smaller than in any other known Mammal, recent or fossil, and even less than in some reptiles. It is, in fact, the most DINOCERATA, TILLODONTIA, AND TOXODONTIA. 373 reptilian brain in any known Mammal. In D. mirabile, the entire brain was actually so diminutive that it could appa- rently have been drawn through the neural canal of all the preesacral vertebree, certainly through the cervicals and lumbars.”’ The head could be lowered to the ground, and though the nasal bones are elongated, there is no evidence of the exist- ence of a proboscis. The limbs are short, the fore-legs shorter than the hind-legs ; and the femur was not provided with a third trochanter. The tail is short and slender, and the ribs are furnished with rudimentary uncinate processes. The feet are furnished with five toes each (fig. 657,8B and C), and have a general resemblance to the feet of the Proboscideans. In the hind-foot the hallux seems to have been small or rudimentary. The chief genera included by Marsh among the Dinocerata are Dinoceras, Uintatherium, and Tinoceras, the last being stated to be identical with the Hobasilews and Lox- olophodon of Professor Cope. All the remains of this singular group which have been hitherto brought to light are from the Middle Eocene of North America. OrpER VIII. Tittopont1a.—This order has been estab- lished by Professor Marsh for the reception of some singular Mammals from the Eocene Tertiary of the United States. The following are the characters of the order, so far as pub- lished: Zhe molar teeth have grinding crowns, as in Ungulates, and may have distinct roots, or may grow from permanent pulps; small canines are present in both jaws ; and each jaw carries two long scalpriform incisors, resembling those of Ro- dents in form and in growing from persistent pulps. The feet are plantigrade and pentadactyle, and the digits were apparently ~unguiculate. The femur has a third trochanter, and the radius and ulna and tibia and fibula are distinct bones. The order includes two distinct families—one, the 7Z%/lo- theride, having molar teeth with distinct roots; whilst the other, Stylinodontide, possessed rootless molars, which grew from persistent pulps. All the known forms of the order are from the Eocene Tertiary, and the typical species seem to have been from one-half to two-thirds of the size of the Tapiv. 374 ORDERS OF MAMMALIA. The type-genus of the order is Ti/lotherium, which presents a remarkable combination of the characters of the Ungulata, Rodentia, and Carnivora. The general form of the skeleton most closely resembles that of the Carnivores, the skull being like that of the Bears in many respects, whilst the feet are five-toed, with the whole sole applied to the ground, and having ungual phalanges similar to those of the Urside. The brain-cavity is of small size, and the cerebral hemispheres did not extend over the cerebellum or the olfactory lobes. The orbits are not complete, but open into the temporal fossee. The premolars and molars have grinding crowns, the canines are of small size, and the preemaxillee carried a pair of large scalpriform incisors (fig. 658), which resemble those WCECC>C = \YX SSS SSS SSS = SSE Fig. 658.—Tillodontia. Side view of the skull of Tillotheriwm fodiens, with the lower jaw displaced downwards, one-fourth of the natural size. (After Marsh.) of the Rodents in having chisel-shaped crowns, and in grow- ing throughout the life of the animal. As in Rodents, there is a corresponding pair of scalpriform incisors in the lower jaw. The dental formula is— _ 2—2 1—1 3—3 3—3 a aC ; pm ——_ 3; ™ - = 34. 2—2 1—1 2—2 3—3 Allied to Tillotherium is the Anchippodus (= Trogosus) of Leidy, from the Eocene deposits of Wyoming. DINOCERATA, TILLODONTIA, AND TOXODONTIA. orto In the group of the Stylinodontidae, besides Stylinodon itself, we have the genus Dryptodon, in which the dental formula is, .d3—3 1—!1 3—3 3—3 v re 3, pm ie TG es ee gue Bae YO | Of the six incisors in each jaw, the four central ones are smnall, but the outermost ones are huge and compressed, faced with enamel, and growing from persistent pulps. The molars and premolars are rootless and cylindrical; and the canines are small. Orper IX. Toxopont1A.—This order includes certain large extinct Mammals from the later Tertiary deposits of South America, the true systematic position of which is still very doubtful ; since they present affinities to the Ungulata, the Rodents, and the Edentates. The skull is massive and the dentition is very peculiar. The molars and premolars are bent so as to be strongly convex outwards and concave in- wards, with flat grinding surfaces (fig. 659), and presenting the peculiarity that they are rootless and grow from per- Fig. 659.—a, Right upper jaw of Toxodon Burmeisteri, and B, left lower jaw of the same ; c, Lower canine. (After Burmeister.) Greatly reduced in size. sistent pulps. Canines are present in the lower jaw, but are of very small size (fig. 659, c) and are placed in the interval between the incisors and premolars. In the upper jaw only the sockets for the canines are left. There are four upper and six lower incisors, which are separated by a wide dias- tema from the premolars. The dental formula is— 376 ORDERS OF MAMMALIA. There is no third trochanter to the femur, but the struc- ture of the manus and pes is quite unknown. The genera of this order are Zowodon and Nesodon, both from late Tertiary or Post-Tertiary deposits in South America. Toxodon was about equal to the Hippopotamus in size; and both genera present a combination of characters so extra- ordinary, that we must await the discovery of more perfect remains before pronouncing any decided opinion as to their true systematic position. oe) ~I ~I CHAPTER XLY. ORDERS OF MAMMALIA (Continued). HYRACOIDEA AND PROBOSCIDEA. ORDER X. HyracorpEA.—This is a very small order which has been constituted by Huxley for the reception of two or three little animals, which make up the single genus Hyraz. These have been usually placed in the immediate neighbourhood of the Rhinoceros, to which they have some decided affinities, and they are still retained by Owen in the section of the Perissodactyle Ungulates. The order is distinguished by the following characters : There are no canine teeth, and the incisors of the wpper jaw are long and curved (fig. 660), and grow from permanent pulps, as they do in the Rodents (such as the Beaver, Rat, &c.) The molar teeth are singularly like those of the Rhinoceros. Ac- cording to Huxley, the dental formula of the aged animal ic—— _2—2 0—0 4—4 3—3 f he EC SU, SO 2—2 0—0 4—-t 3—3 The fore-feet are tetradactylous, the hind-feet tridactylous, and all the toes have rounded hoof-like nails, with the exception of the inner toes of the hind - feet, which have an obliquely- curved nail. There are no clavicles. The nose and ears are short, and the tail is represented by a mere tubercle. The living species of Hyrax are confined to Africa and Syria; and no fossil forms can at present be referred to 378 ORDERS OF MAMMALIA. the order, though various extinct genera (such as Hyracothe- rium, Hyracodon, &c.) have received names founded on sup- posed likenesses to the existing Hyrazx. Fig. 660.—Skull of Hyrax. (After Cuvier.) OrpvER XI. ProposcipeEA.—The eleventh order of Mammals is that of the Proboscidea, comprising no other living animals except the Elephants, but including also the extinct Mastodon and Deinothervwm. The order is characterised by the total absence of canine tecth ; the molar teeth are few im number, large, and trans- versely ridged or tuberculate ; incisors are always present, and grow from persistent pulps, constituting long tusks (fig. 661). In living Elephants there are two of these tusk-like imewsors in the upper jaw, and the lower jaw is without incisor teeth. In the Deinotherium this is reversed, there being two tusk-like lower incisors and no upper incisors. In the Mastodons, the incisors are usually developed in the upper jaw, and form tusks, as in the Elephants, but sometimes there are both upper and lower incisors, and both are tusk-like. Zhe nose is prolonged into a cylindrical trunk, movable in every direction, highly sensitive, and terminating in a finger-like prehensile lobe (fig. 661). The nostrils are placed at the extremity of the pro- boscis. The feet are furnished with five toes each, but some of the toes may be destitute of hoofs. HYRACOIDEA AND PROBOSCIDEA. 319 The recent Elephants are exclusively confined to the tropical regions of the Old World, in the forests of which they live in herds. Only two living species are known— the Asiatic Elephant (Hlephas Indicus) and the African Elephant (Z. Africanus). Fig. 661.—Skull of the Indian Elephant (Elephas Indicus). 71, Tusk-like upper incisors ; m, Lower jaw, with molars, but without incisors; n, Nostrils, placed at the end of the proboscis. (After Owen.) The most important features of the Elephants, from a paleontological point of view, are connected with the nature of the teeth. Canines and lower incisors are invariably wanting, and the “tusks” are formed by an enormous de- velopment of the two upper incisors, which are rootless, and continue to grow throughout the life of the animal. The back-teeth are six in number on each side of each jaw, but owing to their great size and the peculiar mode in which they succeed one another, there is never more than one (or at most portions of two) in place and in use at any given moment. The first three teeth of the grinder-series, which would ordinarily represent premolars, are supposed to be 380 ORDERS OF MAMMALIA. milk-molars, as they have no predecessors or successors ; and the last three are true molars. None of the molars, in fact, undergo vertical displacement (premolars are present in the extinct #. planifrons), but the whole series gradually moves forward in the jaw; and the place of each tooth, as it be- comes gradually worn out, is taken by the tooth next behind it in the series. As regards their form, the molars of the Elephants are extremely massive, with an exceptional vertical development, and composed essentially of transverse laminz of enamel and dentine, more or less copiously united by a coating of cement. The grinding surface of the tooth is always crossed (fig. 662) by more or less numerous ridges, Fig. 662.—a, Left ramus of lower jaw of Elephas (Euelephas) Indicus, viewed from above (after Cuvier); B, Grinding surface of molar tooth of Elephas (Loxodon) Africanus (after Giebel). consisting centrally of dentine, surrounded with an external layer of enamel, and these ridges are sometimes seen to be obviously composed of a transverse and more or less confluent series of tubercles. The triturating surface of the molars, when worn down by use, is more or less flat, and the trans- verse ridges of enamel and dentine give rise to various patterns, which are highly characteristic of different species of the genus. In accordance with the structure of the molar teeth and the form and number of the dental plates, Dr Falconer has divided the genus Elephas into three sections, which are sufficiently useful to be introduced here, though it must be admitted that they are to some extent founded upon an artificial basis, and that there are so many transitional forms HYRACOIDEA AND PROBOSCIDEA. 381 as to render it impossible to limit them with absolute pre- cision. The three sections in question are the following :— 1. Huelephas—Dental lamelle narrow and compressed, the number of the ridges successively increasing in the three true molars from before backwards. The type of this section is the living Hlephas Indicus (fig. 662, A), the “ridge- formula” of which is 12-+16+24—that is to say, there is a progressive increase in the number of the transverse enamel-ridges of the true molars, the first having twelve of these ridges, the second sixteen, and the third and last twenty-four. Besides the living Asiatic Elephant, the section Huelephas includes the Post - Pliocene Mammotli (EZ. primigenius, fig. 663), the Elephas antiquus of the Fig. 663.—Molar of the Mammoth (Elephas primigenius), upper jaw, right side, half natural size. Post-Pliocene. «a, Grinding surface; b, Side view. European Pliocene and Post-Pliocene (fig. 666), and the Elephas hysudricus of the Upper Miocene of the Siwalik Hills, besides other forms of less importance. 2. Loxodon.—Dental lamelle lozenge-shaped or diamond- shaped, not greatly different in number in the three true molars. The type of this group is the living Elephas Africanus (fig. 662, B), in which the “ridge-formula” is 74+8+10. Among the other forms belonging to this section may be mentioned Hlephas planifrons (fig. 664) of the Upper Miocene (Siwalik formation) of India, 2. meri- oO ORDERS OF MAMMALIA. dionalis of the European Pliocene (fig. 665), and the Post- Pliocene £. Melitensis of Malta. 3. Stegodon.—Molars with mammillated tubercles arranged in transverse rows, the number of which is nearly equal in Fig. 664.—Grinding surface of molar tooth of Elephas planifrons, one-third of the natural size. Upper Miocene, India. (After Falconer.) all the molars. The “ridge-formula” of Elephas (Stegodon) insignis is 7-+8-+10. The amount of cement in the molars is much less than in Huelephas and Loxodon, and the promi- nence of the ridges is very conspicuous. The section may be regarded as intermediate between the typical Elephants and the Mastodons, and it comprises the extinct Llephas Cliftii, E. bombifrons, E. Ganesa, and E. insignis of the Upper Miocene (Siwalik formation) of India, the last mentioned of these extending its range into the Pliocene of the same country. The Elephants appear for the first time in the Upper Miocene (Siwalik formation) of India, in which we meet with types of all the three sections of the genus (Huelephas, Loxodon, and Stegodon). In the Phocene period, we find species of Elephants widely distributed over Britain, Europe, Asia, and North America. Of the European Elephants of this period, one of the most important is the lephas (Luelephas) antiquus, a molar tooth of which is here figured (fig. 666). This is essentially a southern form, and is found in Pliocene strata in France and Italy. It survived the Glacial period, and is found abundantly in various Post-Plocene deposits. It abounded in Post- Pliocene times chiefly in Southern Europe, south of the Alps and Pyrenees ; and it is S) HYRACOIDEA AND PROBOSCIDEA. 383 © only on the northern edge of this area that its remains are found commingled with those of the Mammoth. Fig. 665.—Molar tooth of Elephas (Loxodon) meridionalis, one-third of natural size. Pliocene and Post-Pliocene. (After Lyell.) Fig. 666.—Molar tooth of Elephas (Euelephas) antiquus. Penultimate molar, one-third of natural size. Post-Pliocene and Pliocene, (After Lyell.) Another species from the same area is the Elephas (Loxodon) meridionalis, the enamel plates of which are very thick (fig. 665). Its remains have been found in Britain, France, and Italy. In the Post-Phocene, remains of Elephants are numerous, but of these by far the best known and most important is the Mamioth (Zlephas primigenius). This remarkable form (fig. 667) was essentially northern in its distribution, never passing south of a line drawn through the Pyrenees, the Alps, the northern shores of the Caspian, Lake Baikal, Kamschatka, and the Stanovi Mountains (Dawkins). It occurs in the Pre-glacial forest-bed of Cromer in Norfolk, survived the Glacial period, and is found abundantly in Post- glacial deposits in France, Germany, Britain, Russia in Europe, Asia, and North America, being often associated with the Reindeer, Lemming, and Musk-ox.’ That it sur- 384 ORDERS OF MAMMALIA. vived into the earler portion of the human period is unques- tionable, its remains having been found in a great number of instances associated with implements of human manu- facture; whilst in one instance a recognisable portrait of gumeit still adhere to the head, and the Post-Pliocene, Portions of the inte, igenius). thick skin of the soles is still attached to the feet, Fig, 667.—Skeleton of the it has been discovered, carved on bone. From its great abundance in Siberia, it might have been safely inferred that the Mammoth was able to endure a much colder climate than either of the living species. This inference, however, HYRACOIDEA AND PROBOSCIDEA. 385 has been rendered a certainty by the discovery of the body of more than one Mammoth embedded in the frozen soil of Siberia. These specimens had been so perfectly preserved that even microscopical sections of some of the tissues could be made; and in one case even the eyes were preserved. From these specimens, we know that the body of the Mam- moth was covered with a thick coat of reddish-brown wool, some nine or ten inches long, interspersed with coarse black hair more than a foot in length. The molars of the Mam- moth are of the Huelephas type (fig. 663), and the tusks are bent almost into a circle, and may be as much as twelve feet in length. In size, the Mammoth considerably exceeded the largest of the living Elephants, the skeleton being over sixteen feet in length, exclusive of the tusks, and measuring nine feet in height. Amongst other Elephants which occur in Post-Plocene deposits may be mentioned, as of special interest, the pigmy Elephants of Malta. One of these—the Elephas Melitensis, or so-called “ Donkey-elephant ”—was not more than four and a half feet in height. The other—the Hlephas Falconeri of Busk—was still smaller, its average height at the withers not exceeding two and a half to three feet. The Mastodons in most respects closely resemble the true Elephants, from which they are distinguished by their denti- tion. As in the Elephants, the upper incisors grow from permanent pulps, and constitute long tusks (fig. 668); but in the majority of cases the Mastodons also possess lower incisors as well. The two lower incisors, however, though tusk-shaped, did not develop themselves to any extent, and often disappeared in adult life. A more important distinc- tion between the Elephants and Mastodons is that the molar teeth of the latter are not only more numerous (as regards the number present in the jaw at any given moment), but have the peculiarity that their crowns are furnished with nipple-shaped eminences or tubercles placed in pairs, form- ing a number of transverse ridges (fig. 668, B). Each of the three molars possesses a like or nearly ike number of these ridges, but this number varies in different species, and is always much smaller than in the true Elephants. In VOL. II. 2B 386 ORDERS OF MAMMALIA. accordance with this, Dr Falconer divided the Mastodons into two principal sections, which he named respectively Trilophodon and Tetralophodon. In the first of these are such forms as JZ. giganteus (fig. 668, B) of the Post-Phocene, i Ae Ni A Fig. 668.—a, Skull of Mastodon giganteus (= M. Ohioticus); B, Side view of the second true molar of the same. (After Owen.) M. tapiroides and M. angustidens of the Miocene, &c., in which there are three ridges to the molars. In the second group, on the other hand, are such forms as the Miocene J. longirostris and M. latidens, and the Phocene JZ, Arvernensis Fig. 669.—Profile view of the last upper molar of Mastodon Sivalensis, one-third of the natural size. From the Upper Miovene of India. (After Falconer.) (tig. 670), in which the molars are four-ridged. Lastly, in M. Sivalensis (fig. 669) we have a form in which the molars HYRACOIDEA AND PROBOSCIDEA. 387 are tive-ridged, the last being six-ridged; and for this type Dr Falconer proposed the name of Pentalophodon. Fig. 670.—Third milk-molar of the left side of the upper jaw of Mastodon Arvernensis, showing the grinding surface. Pliocene, (After Lyell.) 3 The distribution of the genus Mastodon in time is some- what peculiar, since it commenced both in Europe and Asia in the Miocene, and died out in the Pliccene; whereas in America it does not seem to have made its appearance till the Plocene, and it survived throughout the whole of the Post-Pliocene period. It is clear, then, that JJ/astodon, like Elephas, originated within the Old World, and reached the New World by migration at a later date. Both the Trilo- phodont and Tetralophodont types of the genus appear to have been represented in the Miocene period, the former being represented by the JL tapiroides and I. angustidens of the Upper Miocene of Europe, and the latter by the JZ longirostris of Europe, and the JZ. latidens and MW. Perimen- sis of India; while the Pentalophodont type is represented in the Upper Miocene (Siwalik formation) of India by J/ Sivalensis. In the Pliocene of Europe the best known forms are the I. (Tetralophodon) Arvernensis of Britain and the con- tinent of Europe, the IW Andiwm of South America, and the MW. (Tetralophodon) mirificus of North America. In the European and Asiatic areas, as before remarked, no members of the genus Mastodon have hitherto been detected in de- posits newer than the Phocene; but in North America the ereat Mastodon giganteus or M. Ohioticus abounded in the 388 _ ORDERS OF MAMMALIA, Post-Pliocene period, and another species existed during the same time in South America. J. giganteus ranged from Canada to Texas, and very perfect specimens have been exhumed from morasses and swamps, large individuals at- taining a length of seventeen feet (exclusive of the tusks), the height being eleven feet, and the tusks twelve feet in length. The last of the Proboscidea is the singular Deinotherium of the Miocene, which presents certain points of resemblance to the Sirenians, and is sometimes referred to that order. Fig. 671.—Skull of Deinotherinum Fig. 672.—a, Side view of the third giganteum, Miocene Tertiary. molar of Deinotherium giganteum; B, Grinding surface of the same. Mio- cene Tertiary. (After Kaup.) The genus is principally known by the huge skull of the only certainly determined species—namely, D. gigantewm (fig. 671). The most noticeable feature in the skull is the presence in the lower jaw of two enormous tusk-like incisors, which are directed vertically downwards, in consequence of the abrupt downward flexure of the front portion of the mandible. No canines are present in either jaw, and there are apparently no upper incisors; but both jaws possess a series of pre- molars and molars, the whole of which are in use at one time, the milk-molars being displaced by vertical successors in the usual manner. The crowns of the molars are crossed by strong transverse ridges (fig. 672), and exhibit marked Tapiroid characters, while in some respects they resemble HYRACOIDEA AND PROBOSCIDEA. 389 the molars of the Mastodons. The animal must have attained an enormous size, and it is probable that the curved tusks were used either in digging up roots or in mooring their possessor to the banks of rivers, for its habits were probably aquatic or semi-aquatic. The little that is known of the skeleton, except the skull, would confirm the reference of the genus to the Proboscidea. Deinotherium is only known from the Miocene deposits, and D. gigantewm seems to be the only species. Its remains are found in Germany, France, and Greece, but it has not been discovered in America, and probably did not exist in the New World. CHAPTER XLVI. ORDERS OF MAMMALIA (Continued). CARNIVORA. Orper XII. Carntvora.—the twelfth order of Mammals is that of the Carnivora, comprising the Ferw, or Beasts of Prey, along with the old order of the Pinnipedia, or Seals and Walruses, these latter being now universally regarded as merely a group of the Carnivora modified to lead an aquatic life. The Carnivora are distinguished by always possessing two sets of teeth, which are simply covered by enamel, and are always of three kinds—incisors, canines, and molars—differing from 3 one another in shape and size. The incisors are generally aoe 9 » 1—1 , and are il (except in some Seals); the canines are always invariably much larger and longer than the incisors. The pre- molars and molars are mostly furnished with cutting or trenchant edges ; but they graduate from a cutting to a tuberculate form, as the diet is strictly carnivorous, or becomes more or less miscellane- ous. In the typical Carnivores (such as the Lion and Tiger), the last tooth but one in the upper jaw and the last tooth in the lower jaw are known as the “ carnassial ” teeth, having a sharp cutting edge adapted for dividing flesh, and generally a more or less developed tuberculated heel or internal pro- cess. A varying number, however, of the molars and pre- CARNIVORA. 391 molars may be “ tuberculate,” their crowns being adapted for bruising rather than cutting. As a general rule, the shorter the jaw, and the fewer the premolars and molars, the more carnivorous is the animal. The jaws are so articulated as to admit of vertical but not of horizontal movements; the zygomatic arches are greatly developed to give room for the powerful muscles of the jaws; and the orbits are not separated from the temporal fosse. The intestine 1s com- paratively short. In all the Carnivora the clavicles are either altogether want- ing, or are quite rudimentary. The toes are provided with sharp curved claws. The order Carnivora is divided into three very natural sections :— Section I. Pinnigrada or Pinnipedia.—This section com- prises the Seals and Walruses, in which the fore and hind limbs are short, and are expanded into broad webbed swim- ming-paddles (fig. 673, B). The hind-feet are placed very Fig. 673.—Feet of Carnivora (after Owen). A, Plantigrada, Foot of Bear; B, Pinnigrada, Hind-feet of Seal; c, Digitigrada, Foot of Lion. far back, nearly in a line with the axis of the body, and they are more or less tied down to the tail by the integuments. Section II. Plantigrada. — This section comprises the Bears and their allies, in which the whole, or nearly the whole, of the foot is applied to the ground, so that the animal walks upon the soles of the feet (fig. 673, A). 392 ORDERS OF MAMMALIA. Section III. Digitigrada.—This section comprises the Lions, Tigers, Cats, Dogs, &c., in which the heel of the foot is raised entirely off the ground, and the animal walks upon the tips of the toes (fig. 673, c). As regards their general distribution in time, if the little Microlestes of the Upper Trias be Marsupial, as is almost certainly the case, then the order Carnivora is comparatively modern, the earliest undoubted remains having been found in the Eocene Tertiary. In the Eocene period, however, the familes of the Canide, Viverridw, and Felide appear to have been already differentiated. The Urside, Mustelide, Hyenide, and Phocide, do not seem to have made their appearance before the Miocene period. In the Phocene and Post-Phocene periods almost all the existing types of the Jarnivora are represented by extinct forms, whilst in the latter the remains of various living species are found asso- ciated with other animals which have at the present day en- tirely passed away. In the following are given the charac- ters and chief fossil forms of the families of the Carnivora. SecTION I. PINNIGRADA.—This section of the Carnivora comprises the amphibious Seals and Walruses, which differ from the typical Carnivores merely in points connected with their semi-aquatic mode of life. The body is elongated, somewhat fish-like in shape, and terminated by a short conical tail. All the four limbs are present, but they are very short, and the five toes of each foot are united by the integuments, so as to form powerful swimming-paddles. The hind-feet are placed very far back, their axis nearly coinciding with that of the body (fig. 673, B). Owing to this circumstance the hinder end of the body forms an admirable swimming apparatus, similar in its action to the horizontal tail-fin of the Cetacea and Sirenia. The dentition varies ; but teeth of three kinds are always present, in the young animal at any rate. The canines are always long and pointed, and the molars are generally furnished with sharp cutting edges. There is always a diminution of the incisors below their normal number of six in each jaw, and the molars are never divided into carnassials and tubercular molars. CARNIVORA. 393 The Seals (Phocidw) and Sea-lions (Otaria) are distin- guished by having incisor teeth in both jaws, and by the fact that the canines are not immoderately developed. As regards their distribution in time, the Seals are indicated as occurring in the Miocene (Otaria) and Pliocene Tertiary (Pristiphoca) ; but their remains are by no means as abun- dant as might have been anticipated from their aquatic habits. Remains of Seals, however, are by no means very rare in Post-Tertiary deposits. The Walruses (Zvrichecidw) are distinguished from the Seals by their enormously-developed upper canines, which grow from persistent pulps, and constitute great pointed tusks. Remains of large Pinnigrade Carnivores (7richecodon) have been described from the Pliocene Tertiary of Europe, and appear to be nearly allied to the existing Walrus (Lrichecus). Section II. PLantrGrapA.—The Carnivorous animals be- longing to this section apply the whole or the greater part of the sole of the foot to the ground (fig. 673, A); and the portion of the sole so employed is destitute of hairs in most instances (the sole is hairy in the Polar Bear). The typical family of the Plantigrade Carnivora-is that of the Urside or Bears, in which the entire sole of the foot is appled to the ground in walking. The Ursidw are much less purely carnivorous than the majority of the order, and, in accordance with their omnivorous habits, the teeth do not exhibit the typical carnivorous characters. The incisors and canines have the ordinary carnivorous form, but the “ carnas- sial”’ or sectorial molar has a tuberculate crown instead of a sharp cutting edge. The dental formula is— _3—3 I1—I1 4+—4 2—2 4 - 5G 5 pin ; m = 42. 1—1 4+—-4 3—3 The claws are large, strong, and curved, but are not re- tractile. The tongue is smooth; the ears small, erect, and rounded ; the tail short; the nose forms a movable truncated snout ; and the pupil is circular. The Bears make their appearance at a comparatively late date, the oldest known types being referable to the genus 9 394 ORDERS OF MAMMALIA. Hycenarctos, which commences in the Miocene. Species of Hyenarctos are found in the Miocene of France, and in the Tertiary deposits of the Siwalik Hills in India, and also in the Pliocene of Europe and South America, so that the range ~ of the genus is very extensive. The Miocene genus Amphi- cyon, though resembling the Bears in being plantigrade and a climber, is best considered as an aberrant member of the Canide. The Arctotherium of the late Tertiary deposits of South America seems to be related to the living “ Spectacled Bear” of Chili; and the existing genus Ursus is represented in the Plocene of Europe and India, one of the best known forms being the Ursus Arvernensis of France. In the Post- Tertiary period the two most important species are the Ursus priscus and Ursus speleus, of which the former is apparently identical with the living Grizzly Bear (Ursus ferox). The Cave-bear (Ursus speleus, fig. 674) is a gigantic Bear, which, Fig. 674.—Skull of Ursus speleeus. Post-Pliocene. as its name implies, has been found mainly in cavern-deposits. The size of this species considerably exceeded that of any existing Bear, and it is especially characteristic of the later portion of the Post-Phocene period. More or less nearly allied to the true Bears are the little living animals which are known as Coatis (Vasa), Racoons (Procyon), and Kinkajous (Cercoleptes), all of which at the present day are confined to the American continent. The Leptarchus of the Pliocene of North America is the oldest Ursine type known in this continent, and seems to be allied CARNIVORA. 395 to the Coatis. The bone-caves of Brazil have yielded re- mains of two species of Naswa, and a Racoon has been found in Post-Tertiary deposits in Hlinois. No certain remains of Cercoleptes are known; but the Arctocyon primevus of the Eocene Tertiary of France has been compared with the exist- ing Kinkajous. The only remaining family of the Plantigrada is that of the Melide or Badgers, characterised by their elongated bodies and short legs, and by the fact that the carnassial tooth has a partly cutting edge, and is not wholly tuberculate as in the Bears. The earliest remains of Melidw are from the Upper Miocene deposits of the Siwdlik Hills in India, in which we meet with the living genus J/ellivora (comprising the Honey- badgers), and the allied but extinct Ursitaxus. Remains of Badgers have been found in Post-Tertiary de- posits in Europe, and they are probably referable to the existing Meles taxus. The Gluttons (Gulo) are also only known from Post-Tertiary accumulations, and the so-called Gulo speleus of the cavern-deposits of Europe does not appear to be separable from the common Wolverine (Gulo luscus). Section IIT. Drarrrcrapa.—In this section of the Carni- vora the heel is raised above the ground, with the whole or the greater part of the metacarpus, so that the animals walk more or less completely on the tips of the toes (fig. 673, C). No absolute line, however, of demarcation can be drawn between the Plantigrade and Digitigrade sections of the Car- nivora, since many forms (e. g., Mustelide and Viverride) exhibit transitional characters, and it has even been proposed to place these in a separate section, under the name of Sem- plantigrada. The first family of the Digitigrada is that of the Mustelide, or Weasels and Otters, including a number of small Carnivores, with short legs, elongated worm-like bodies, and a peculiar gliding mode of progression (hence the name of Vermiformes, sometimes applied to the group). The Mustelide appear for the first time during the Miocene period, at which time there existed in the Old World a con- siderable number of types referable to this family. Thus in 396 ORDERS OF MAMMALIA. the Miocene Tertiary of Western Europe, we meet with species of the existing genera Mustela (Weasels) and Lutra (Otters), together with the extinct Promephitis and Palco- mephitis, and the Otter-like Potamotheriwum. In the same deposits are found the transitional types Lutrictis and Taxo- don ; the former intermediate between the Martens and the Civets, with affinities to the Otters; while the latter has relationships with both the Otters and the Badgers. Lastly, in the Upper Miocene of the Siwalik Hills in India we have species of Otter (Zutra), and the related but extinct genus Enhydriodon. The second family of the Semi-plantigrade Carnivores is that of the Viverride, the Civets and Genettes. They are all of moderate size, with sharp muzzles and long tails, and more or less striped, or banded, or spotted. The carnassial molar is trenchant ; the canines are long, sharp, and pointed; and the tongue is roughened by numerous prickly papille. The last two upper molars and the last lower molar are tubercular. The claws are semi-retractile, and the pupils can contract, on exposure to light, till they resemble a mere line. The Viverride appear to commence in the Eocene Tertiary, being represented in deposits of this age in Europe by the genera Tylodon and Palwonyctis, and in North America by Viverravus. In the Lower Miocene of Europe occurs the extinct genus Proviverra; and the researches of Gaudry have thrown an interesting hght upon the Viverrine Jcé?- thervum, from the Upper Miocene deposits of Attica. In this genus, though the upper jaw resembles that of the true Civets in possessing two tubercular molars behind the carnas- sial (fig. 675), the hindmost of these is of small size, and sometimes almost rudimentary, thus approximating to the type of the Hyzenas, in which this tooth is altogether want- ing. The hind-feet, further, have only four toes. Of latei forms, we may note the Galecynus of the Plocene of Ciningen, in Switzerland, which seems to be intermediate between the Civets and the Dogs. Forming a transition between the Vivervid@ and the Pelide is the family of the Hyenide, distinguished by the fact that, CARNIVORA. 397 alone of all the Carnivora, both pairs of feet have only four toes each. The hind-legs are shorter than the fore-legs, so that the trunk sinks towards the hind-quarters, and the tail is short. The tongue is rough and prickly. The head is Fig. 675.—Teeth of the left side of the upper jaw of Letithe: twin robustuin, Vieweu iru below, of the natural size. Upper Miocene, Attica. (After Gaudry.) extremely broad, the muzzle rounded, and the muscles of the jaw extremely powerful and well developed. The claws are non-retractile. All the molars are trenchant except the last upper molar, which is tuberculate. The upper carnassial has a small internal tubercle, and the lower carnassial is wholly trenchant. The earliest Hyenas appear in the Upper Miocene de- posits of the Siwdlik Hills and of Europe, in which occur the Fig. 676.—Skull of Hyena spelwa, Post-Pliocene. remains of the genus Hyena itself. In the Upper Miocene of Greece are found the two extinct genera Hycanictis and Lycena, the former with affinities to the Viverride. In the 398 ORDERS OF MAMMALIA, Pliocene period the genus Hyena was well represented in Europe, the best known species being the H. hipparionuwm ot France. Of the Post-Tertiary Hyzenas, the best known and most important is the great Cave-hyena (Hyena spelea, fig. 676). This species in many respects resembles the Hywna crocuta of South Africa, of which it is probably only a vari- ety ; and it inhabited Britain and the greater part of Europe during the Post-Phocene period. Its remains often occur in great abundance, and no doubt can be entertained as to its having survived into the human period. The next family is that of the Canidw, comprising the Does, Wolves, Foxes, and Jackals. The members of this family are characterised by having pointed muzzles, smooth tongues, and non-retractile claws. The fore-feet have five toes each, the hind-feet have only four. The molar teeth are 6==6 1 , sometimes ———, and of these, two or three on each 7—7 T—IT side are tuberculate. The carnassial has a tolerably large heel or process. Fig. 677.—Skull of Jackal (Canis aureus). The true Dogs and the Wolves, forming the genus Cais, and the Foxes (Vulpes), can hardly be distinguished from one another, as fossils, with any certainty. The oldest known types of the Canidw appear in the Eocene of Europe and North America, though the true position of most of these early forms is somewhat uncertain. The Vulpavus of North America seems to be related to the living Foxes (Vulpes) ; and the European Eocene has yielded various extinct genera, such as Galethylax, Cynotherium, and Cynodon, which are CARNIVORA. 399 probably referable to the Canidw. Cynodon (fig. 678) seems to be intermediate between the Canide and the Viveriide, Fig. 678.—Left ramus of the lower jaw of Cynodon lacustris, of the natural size. Eocene, France. (Altered from Gaudry.) agreeing with the former in having two tubercular molars behind the carnassial on each side of the lower jaw, while it approaches the Civets in having an internal process to the lower carnassial. We may also provisionally place in the Canide the curious Arctocyon of the Eocene Tertiary of France, though it is a very generalised type, and possesses peculiarities which prevent it being definitely placed in any family of the existing Carnivores. In the Miocene Tertiary we meet with a number of types of this family, including the existing genus Canis, which has been detected in deposits of this age in North America. Of other Miocene forms, Psewdocyon seems to be allied to the Dogs ; Hemicyon is in some respects intermediate between Cans and Gulo; and Stmocyon, of the Upper Miocene of Greece, is an aberrant type, with molars like those of the Dogs, and canines resembling those of the Felidwe. The most important of the Miocene Canidw, however, is Amphi- cyon, species of which have been found in Europe, India, and North America. In many of its characters this genus is generalised, since its hind-feet were pentadactylous—those of the Dogs being four-toed—and its mode of progression seems to have been plantigrade, as in the Bears. There existed also an additional molar on each side of the upper jaw, and all the molars were tuberculate. The dentition was therefore complete, the dental formula being— 400 ORDERS OF MAMMALIA. In the true Dogs, on the other hand, an upper molar is missing, and there are thus only two tubercular teeth behind the upper carnassial (the fourth premolar); the dental formula bemg— . 3—3 1—1 4—4 2—2 jy Se ; pm ; mM =42 3—3 1—1 4——4 3—3 In the Phocene period, especially in North America, species of Canis seem to have abounded, and the same is true of the Post-Pliocene, some of the Post-Tertiary forms beige nearly or quite inseparable from existing species. Thus, the so-called Canis familiaris fossilis of the caves of Germany, Belgium, and France, appears to be very nearly allied to the domestic Dog of the present day. Similarly, the so-called Canis speleus, and Canis vulpes speleus are nearly, if not quite, identical with the existing Wolf and Fox of Europe. We may here intercalate the singular extinct genus Hycnodon, with its allies, for which it is necessary to estab- lish the distinct family of the Hyenodontide. Hycenodon 1s found in the Eocene and Miocene Tertiary of Europe, and in deposits of the latter age in North America, and is remark- able on account of the nature of its teeth. The dentition is complete, the dental formula bein y— o 5 9 9 j 2 9 Bid -—— 9} leat 4—4 (9 Soret D 1 ene 3 pm 5 am = 445 3I—9d 1—1 4—4 I—3 Moreover, there is the character—unexampled among the existing Carnivores — that a// the molars have trenchant edges, and are of the “carnassial” or sectorial form; and there are no “tubercular” molars (fig. 679). In this respect Hyaenodon approximates to the living Marsupial genus Zhyla- cinus. The extinct genus Pterodon of the European Eocene is nearly allied to Hywnodon, as is also the Dromocyon of the Middle Eocene of North America. The latter, however, has only four lower incisors. Jesonyx and Limnocyon, of the American Eocene, also seem to properly find a place in the family of the Hyenodontide, though the former has some very peculiar characters. The last group of the Digitigrada is that of the Felda, or CARNIVORA. 401 Cat tribe, comprising the most typical members of the whole order of the Carnivora, such as the Lions, Tigers, Leopards, Cat, and Panthers. The members of this family all walk upon the tips of their toes, the soles of their feet being hairy, Fig. 679.—Teeth of Hyewnodon horridus, viewed from one side, reduced in size, the lower canine and incisors being wanting. Miocene Tertiary, North America. (After Leidy.) and the whole of the metacarpus and heel being raised above the ground (fig. 673, c). The jaws are short, and, owing to this fact, and to the great size of the muscles concerned in mastication, the head assumes a short and rounded form, Fig. 680.—Side view of the skull of the Lion (Felis Jeo). with an abbreviated and rounded muzzle. The molars and premolars are fewer in number than in any other of the Carnivora (hence the shortness of the jaws), and they are all trenchant, except the last molar in the upper jaw, which is tuberculate. The upper carnassial has three lobes, and a blunt heel or internal process. The lower carnassial has two cutting lobes, and no internal process. The dental formula is— VOL. II. 2C Pigsboas 402 ORDERS OF MAMMALIA. 3—: 1—1 3—3 1—1 a IC 5; pm = Wa — 3I—3 1—1 2—2 1—1 The legs are nearly of equal size, and the hind-feet have only four toes each, whilst the fore-feet have five. All the toes are furnished with strong, curved, retractile claws, which, when not in use, are withdrawn within sheaths by the action of elastic ligaments, so as not to be unnecessarily blunted. The earliest known type of the true Felidw would seem to be the Zimnofelis of the Middle Eocene of North America, which appears to be a genuine Cat, though its structure is not fully known. There are also other Eocene types, which, when fully understood, may prove to be referable to this family. In the Miocene period true Felidw abounded, as also in the Plocene, both in Europe and North America. In addition to various forms referable to the existing genus Felis, the Miocene deposits have yielded the remains of the singular extinct genera Pseudelurus, Dinictis, and Machair- odus. The first of these differs from Felis proper, in pos- sessing an additional premolar in the lower jaw, and it is found in the Miocene of Europe and the Pliocene of North America. Dunictis, on the other hand, not only has an ad- ditional lower premolar on each side, but it possesses a minute tubercular molar behind the carnassial tooth. It occurs in the Miocene of North America. Lastly, the genus Machairodus includes the so-called “sabre-toothed Tigers,” and is widely distributed both in space and time, ranging from the Miocene to the close of the Post-Plocene, and being already known to occur in Britain, in the Continent of Europe, in India, and in North and South America. Machairodus presents us with the Carnivorous type in the most specialised condition at present known; the upper canines beige extraordinarily developed, trenchant, and sabre-shaped, with finely-serrated margins (fig. 681). No true molar is present in the upper jaw, and the premolars are reduced to two on each side of each jaw. The dental formula is— _3—3 1—1 2—2 0—0 ; Somer Meme P ea STs = 26. 3I—3 1— 2—2 1—] CARNIVORA. 403 The Post-Pliocene deposits of the Old and New World contain a great number of Felida, some belonging to extinet types, but the majority referable to genera now in existence. Of the latter, the most interesting and important form is the great Cave-lion (Felis spelea) of Europe, which does not appear to be separable by any character of importance from Fig. 681.—a, Skull of Machairodus cultridens, without the lower jaw, reduced in size ; B, Canine tooth of the same, one-half the natural size. Pliocene, France. the existing Lion (Felis leo). This species inhabited Britain in times subsequent to the Glacial period, and was a con- temporary of the Cave-hyzena, Cave-bear, Woolly Rhinoceros, and Mammoth. There can also be no doubt but that the Cave-lion survived into the earher portion of the human period. 404 CHAPTER XLVII. ORDERS OF MAMMALIA (Continued). LODENTIA, CHEIROPTERA, AND INSECTIVORA. OrpER XIII. Ropentia.— The thirteenth order of J/am- malia is that of the Rodentia, or Rodent Animals, often spoken of as Gives, comprising the Mice, Rats, Squirrels, Rabbits, Hares, Beavers, &e. The Rodentia are characterised by the possession of two long curved imneisor teeth in each jaw, separated by a wide in- terval from the molars. The lower jaw never has more than two of these imeisors, and the upper jaw rarely; but some- tines there are four upper incisors. There are no canine teeth, and the molars and premolars are few in number (rarely more than four on each side of the jaw). The feet are usually fur- nished with five toes each, all of which are armed with claws ; and the hallux, when present, does not differ in form from the other digits. The most characteristic point about the Rodents is to be found in the structure of the incisors, which are adapted for continuous gnawing—hence the name of Rodentia. The incisor teeth are commonly two in each jaw, and they grow from persistent pulps, so that they continue to grow through- out the life of the animal. They are large, long, and curved (fig. 682, A), and are covered anteriorly by a plate of hard enamel. The back part of each incisor is composed only of the comparatively soft dentine, so that when the tooth is exposed to attrition, the soft dentine behind wears away RODENTIA, CHEIROPTERA, AND INSECTIVORA. 405 more rapidly than the hard enamel in front. The result of this is that the crown of the tooth acquires by use a chisel- like shape, bevelled away behind, and the enamel forms a persistent cutting edge. The gnawing action of the incisors is assisted by the articulation of the lower jaw, the condyle of which is placed Fig. 682.—a, Side view of the skull of Sciwrus (Cynomys) Ludovicianus ; B, Molar teeth of the upper jaw of the Beaver (Castor fiber). (After Giebel.) longitudinally and not transversely, so that the jaw slides backwards and forwards. The molars, consequently, have flat crowns (fig 682, B), the enamelled surfaces of which are always arranged in transverse ridges, in opposition to the antero-posterior movements of the jaw. The Rodents make their first appearance in the Eocene Tertiary, and abound at the present day. Very many fossil forms are known, and many of these, even of the oldest, belong to genera still in existence, though few are of special interest. The order fodentia comprises a very large number of families, of which only those containing important fossil representatives can be noticed here. ; Fam. 1. Leporide.—In this family are the Hares (Lepus timidus) and Rabbits (Lepus cuniculus), distinguished amongst the Rodents by the possession of two small in- cisors in the upper jaw, placed behind the central chisel- shaped incisors, so that there are four upper incisors in all. The molars and premolars are rootless, and the dental formula is— 406 ORDERS OF MAMMALIA. _2—2 0—0 3—3 3—3 Cia Ce i = 28. 1—1 0—0 2—2 o—: The clavicles are imperfect. The fore-legs are furnished with five toes, and are considerably shorter than the hind- legs, which have only four toes. The two orbits communi- cate by an aperture in the septum. Generally there is a short erect tail. The genus Zepus itself is found in the Phocene deposits of both North and South America, and in the Post-Pliocene cave-deposits of Brazil occurs a Hare, nearly allied to the living L. Brasiliensis. In the Miocene of North America the Hares are represented by the extinct genus Palwolagus, and in the Phocene of the same country we have the extinct genus Panolar. Forms closely allied to, or actually be- longing to, the genus Zepus have also been indicated as occurring in the Miocene, Pliocene, and Post-Pliocene deposits of Europe. fam. 2. Lagomyde.—In the Calling-hares or Pikas (Lagomys), which form this family, the legs do not differ much in size, there is no visible tail, and the clavicles are nearly complete. They are found in Russia, Siberia, and North America. The existing genus Lagomys is found as early as the Miocene in France, and occurs also in the Pliocene of Europe, while the Cave-pika is found in the Post-Glacial deposits of Britain. The Zitanomys of the French Miocene differs from Lagomys chiefly in the possession of a lower molar fewer (fig. 683, D). In the neighbourhood of the Hares and Calling- hares we may provisionally place the remarkable and aberrant Zypotherium (or Mesothervum) ot the Phocene of South America, which presents affinities both to the Toxodonts and the Unegulates, and which can- not at present be definitely referred to any family of the Rodents. This singular form was larger than the existing Capybara, and therefore possessed dimensions greater than those of any living Rodent. It had clavicles, and the fore- feet were pentadactylous, while the hind-feet had only four toes. The dental formula is— RODENTIA, CHEIROPTERA, AND INSECTIVORA. 407 Fam. 3. Cavide.—In this family are the hving Capybaras (Hydrocherus), Agoutis (Dasyprocta), Pacas (Celogenys), &c., characterised by their absence of clavicles, their rudimentary tail, their unguiculate toes, and their general possession of eight rootless molars in each jaw (fig. 683). Almost all the existing members of this family belong to South America, and this continent has been peopled during Post-Tertiary times with numerous species more or less nearly allied to living forms. Thus, the Brazilian bone-caves have yielded to the researches of Lund remains of Guinea-pigs (Anema), Agoutis, Pacas, and Capybaras, all of which appear to be- long to extinct species. The Capybaras (Hydrochwrus) seem to have extended their range to North America during the Post-Pliocene period ; while Cavies occur in South America as early as the Pliocene. Remains from the Miocene of Europe have also been discovered indicating the past exist- ence of Cavies and Agoutis in this region. Fam. 4. Hystricide—In this family are the well-known Porcupines, distinguished from the other Rodents by the fact that the body is covered with long spines or “ quills,” mixed with bristly hairs. They have four molars on each side of each jaw, and they possess imperfect clavicles. The genus Hystriz appears first in the Upper Miocene of Europe, in the person of a species nearly allied to the hving H. cristata, and other forms appear in the Phocene of the same region. The H. venustus of the Pliocene of North America is also related to the H. cristata of Southern Europe. Fam. 5. Cercolabide.—This family is hardly separable from the preceding, the chief difference being that the animals composing it spend more or less of their lves in trees, and are therefore adapted for climbing. The only fossil form referable to this family is a large Cercolabes found in the Post-Pliocene cave-deposits of South America, in which region the genus still survives. Fam. 6. Octodontide.—This family includes a large number 408 ORDERS OF MAMMALIA. of living Rodents which are principally South American and African (Octodon, Echimys, Ctenomys, &c.) The most important extinct type of this family is the Theridomys of the Eocene and Miocene of Europe, and of the Eocene of South America (fig. 683, B), which is allied to the living Spiny Rats (Zchimys), and also has points of relation- ship with the Beavers. The Megamys of the South American Eocene and the Palwomys of the Miocene of Europe are, fur- ther, beheved to be related to the hving Capromys of the West Indies. Lastly, the genus Ctenomys occurs in the Pliocene of South America; and the bone-caves of Brazil have yielded remains of Hchimys, together with a species of Coypu (Myopotanus). Fam. 7. Chinchillide.—This family includes some South American Rodents, of which the true Chinchillas (Chinchilla) are the best known. They are small nocturnal animals, strictly terrestrial in their habits, and having the hind-legs considerably longer than the fore-legs. We may, perhaps, place in this family the extinct genus Archeomys (fig. 683, A) from the Miocene of France. Fig. 6838.—a, Lower molars of Archwomys chinchilloides—Miocene, France; B, Upper molars of Theridomys Lembronica—Miocene, France ; c, Lower molars of Chalicomys Jegeri— Miocene, Germany ; p, Left ramus of lower jaw of Titanomys Visenoviensis—Miocene, France ; rE, Two lower molars of the living Lemming (Lemmus Norvegicus); ¥, Lower molars of the living Paca (Celogenys paca) ; G, One of the lower molars of the living Beaver (Castor jiber). Species of Viscacha (ZLagostomus) have also been found in the Pliocene and Post-Pliocene deposits of South America ; and the cave-deposits of Anguilla in the West Indies have yielded the remains of the extinct genera Amblyrhiza and Loxomylus, RODENTIA, CHEIROPTERA, AND INSECTIVORA. 409 Fam. 8. Castoride.—The best-known example of this family is the Beaver (Castor fiber). The distinctive pecu- liarities of the family are the presence of distinct clavicles, the possession of five toes to each foot, and the fact that the hind-feet are webbed, adapting the animal to a semi- aquatic life. A considerable number of fossil Castoride are known, commencing with the Steneofiber of the Miocene of France, and the Paleocastor of the Miocene of North America. The genus Castor itself is said to occur in the French Miocene, and is certainly present in the Pliocene of Europe. The Castor speleus of the European cave-deposits does not appear to be specifically separable from the existing Beaver (Castor fiber). The great Trogontherium (fig. 684) of the Post- Tertiary deposits of Europe, also appears to be hardly gen- erically separable from Castor. The Castoroides Ohioensis of the Post- Tertiary period of North America seems to be rightly referred to a separate genus. The only known species attained a compara- tively gigantic size, reaching a length of about five feet. Lastly, the Chalicomys of the European Miocene and Plio- cene deposits appears to be nearly related to the Beavers, if it be really generically distinct. fam. 9. Muride—tThe next family of Rodents is that of the Muride, comprising the Rats, Mice, and Lemmings. In this family the tail is long, always thinly haired, sometimes naked and scaly. The lower incisors are narrow and pointed, and there are complete clavicles. The hind-feet are fur- nished with five toes, the fore-feet with four, together with a rudimentary pollex. The remains of Muride are abundant in the Tertiary deposits, the oldest being the extinct Mysops and Colonomys of the Eocene of North America. In the Miocene of France are various species of the extinct genus Cricetodon, allied to the living Hamsters (Cricetus), together with species of Fig. 684,—Jaw of Trogontherium Cuvieri. Post. Pliocene. 410 ORDERS OF MAMMATIA. Myarion, supposed to be nearly allied to the existing Hes- peromys of North America. The genus Cricetus, comprising the existing Hamster, is known to occur in the Pliocene deposits of Europe, and is represented in Post-Tertiary deposits by a form probably identical with the lvinge C. vulyaris. The Lemmings (Myodes) are represented by at least one species in Post- Tertiary deposits in Britain, occurring after the Glacial period, and being contemporary with “ palolithic” man. The Voles or Campagnols (Avvicola) commence in the Pliocene, and are abundantly represented in Post-Tertiary deposits. The Post-Glacial deposits of Britain have yielded remains of the cellular envelope. The Stigmariw are generally found rami- fying in the “underclay,” which forms the floor of a bed of coal, and which represents the ancient soil upon which the Sigillarve grew. : Of the remaining genera of the Sigillarioids, Rhytidolepis is the most important. It is characterised by the possession of large, hexagonal, tripunctate areoles, and narrow, often trans- versely striate ribs. In Favularia, lastly, the smaller branches were destitute of ribs, with elliptical, spirally-disposed areoles. The stem branched dichotomously—lhke that of a Lepidoden- dron—and the leaves were broad, with numerous parallel veins, approximating to the leaves of Cordaites. J. Conifere.—True Conifers have long been known to occur in the Carboniferous rocks. They belong to the genera Dadoxylon, Palewoxylon, Araucarioxylon, and Pinites. They are recognised by the great size and concentric rings of their prostrate, rarely erect trunks, and by the fact that the micro- scope exhibits punctated fibres in their wood. ‘Their fruit is unknown, unless, as is very probable, it is constituted by the so-called Trigonocarpa. If this be the case, the Carbonifer- ous Conifers must have been “ Taxoid,” resembling the recent Yews in producing berries instead of true cones. The so- 462 PALAOBOTANY. called Sternbergia, as has been already pointed out, are “pith- cylinders,” or, in other words, casts of the pith, of Dadoxylon. They appear, however, to belong also to Sigillaria and Lepi- dophlovos. g. Cycadacee.—The peculiar group of Gymnospermous Exogens represented at the present day by the Cycads is not known with certainty to be represented in the Carbon- iferous rocks. Nawggerathia has been referred here, and the Cycadaceous genus Pterophyllum has also been alleged to occur. Brongniart has also conjectured that the Sigillarioids are in reality most nearly allied to the Cycadacew ; and this opinion is supported by other high authorities. h. Angiospermous Exogens—The occurrence of true Angio- sperms in the Carboniferous period is very doubtful. No Exogenous wood which is not Coniferous has been as yet detected. The fossil known as Antholithes, which was at one time conjectured to be possibly the inflorescence of an An- giosperm, has now been shown to be really a raceme bearing the fruit termed Cardiocarpon ; and it remains uncertain to what plant this really belongs. i. Monocotyledons.—The occurrence of Endogens in the Coal-formation is also attended with some uncertainty. The genus Veggerathia has sometimes been referred to the Palms, and the same group has been asserted to be represented by species of Palmacites. The curious twisted bodies referred to the genus Spirangiwm are supposed to be the fruits of Mono- cotyledons, but their true nature is uncertain. The only ap- parently unequivocal proof of the occurrence of Carboniferous Endogens is, however, afforded by the so-called Pothocites, which appears to have been the spadix of an Aroideous plant ; but even this determination is not free from doubt. PERMIAN PLANTS.—The Permian Flora is, upon the whole, very nearly allied to that of the Coal-measures, though the Permian species are mostly distinct, and there are some new genera. Thus, we find species of Lepidodendron, Calanutes, Equisetites, Asterophyllites, Annularia, &e——all genera which are highly characteristic of the Carboniferous period. On the other hand, the Sigillarioids of the Coal appear to have finally passed away with the close of the Carboniferous period. THE CARBONIFEROUS AND PERMIAN FLORAS. 463 Ferns are abundant in the Permian rocks, and belong for the most part to the well-known Carboniferous genera Aletho- pteris, Neuropteris, Sphenopteris, and Pecopteris. There are also Tree-ferns referable to the genus Psaronius. The singular genus Neggerathia (fig. 711) is represented in the Permian, and is supposed, with more or less probability, to be a Cycad- aceous plant. It has pinnate leaves, with cuneiform leaf- lets, the venation of which resembles that of some Cycads. The Conifers of the Permian period are numerous, and Fig. 711.— Neggerathia expansa. Permian. belong in part to Carboniferous genera. A characteristic genus, however, is Walchia (fig. 712), distinguished by its lax short leaves. This genus, though not exclusively Permian, is mainly so, the best-known species being the W. piniformis. Here, also, we meet with Conifers which produce true cones, and which differ, therefore, in an important respect from the Taxoid Conifers of the Coal-measures. One of the most characteristic of these is the Ullmania selaginoides, which 464 PALAOBOTANY. occurs in the Magnesian Limestone of Durham, the Middle Permian of Westmorland, and the “ Kupfer-schiefer” of Germany. =e ae ZZ Fig 712.—Walchia piniformis. a, Branch; b, Twig. From the Permian of Saxony. (After Gutbier.) CHAP Iii Lr FLORAS OF THE SECONDARY AND TERTIARY PERIODS. Triassic PLAnts.—With the Trias we commence what has been aptly termed the “ Age of Cycads,” from the predomi- nance of the plants of this group in the Mesozoic vegetation. The Cycads are a group of Gymnospermous Exogens, the form and habit of growth of which present considerable re- semblance to those of young Palms (fig. 713). The trunk is Fig. 713.—Zamia spiralis, a living Cycad. Australia, unbranched, often shortened, and bearing a crown of pinnate fronds. The leaves are usually “ circinate ”—that is, they unroll in expanding, like the fronds of Ferns. The ovules are borne upon the edge of altered leaves, or are carried on the scales of a cone. All the existing species of Cycads are natives of warm countries, occurring in South America, the Wes 1 2G 466 PALE OBOTANY. West Indies, Japan, Australia, Southern Asia, and South Africa. As has been already remarked, the occurrence of genuine Cycads in the Carboniferous vegetation has not been demonstrated, and the same holds good of all the Paleozoic floras. True Cycads, therefore, so far as known, make their first appearance in the Trias, at the commencement of the Mesozoic period, where they are represented by the genera Pterophyllum, Zamites, and Podozamites. Cycads continue to be abundantly represented throughout the whole Mesozoic series ; but they have only been detected by a single dubious example in strata of Tertiary age. The name “ Age of Cycads,” as applied to the Secondary epoch, is therefore, from a botanical point of view, an exceedingly appropriate one. Besides Cycads, the Triassic rocks have yielded the re- mains of Ferns, Hgwisetites, Calamites, and Conifers. The Ferns belong mostly to the genera Neuropteris, Pecopteris, Acrostichites, Crematopteris, Cyclopteris, and -Ano- mopteris. A characteristic species of the first of these is figured below (fic. 714). The Conifers of the Trias, lastly, are abundant, the most characteristic genus being Voltzia. Fig. 714.—Newropteris elegans. Trias. This genus is related to the existing Cypresses, and many species of it are found in the Triassic rocks. Jurassic PLAN’s.—Taken as a whole, the Jurassic period is characterised by the prevalence of Ferns, Cycads, and Conifers ; no Palms or Angiospermous Exogens having been as yet shown to occur. FLORAS OF SECONDARY AND TERTIARY PERIODS. 467 The Cycads are extremely abundant, and belong chiefly to the genera Pterophyllum, Otozamites, Zanvites, Bucklandia, Crossozamia, Williamsonia, Mantellia, &c. The “ dirt- bed,” as it 1s called, of the Purbeck beds, consists of an ancient soil, in which stand erect the trunks of Conifers and the stems of Cycads of the genus MZan- tellia (fig.715). The fronds of Cycads occur also in ereat abundance in various Jurassic strata, especially Fig. 715 —Mantellia (Cycadeoidea) megalophylla, a Cycad from the Purbeck ‘‘dirt-bed.” Upper Oolites. in the-lower portion of the series; and the cones likewise have been in some instances preserved. The Conifers are repre- sented by various genera more or less nearly allied to the present Araucarie, and cones have been in a few instances detected. Ferns occur very abun- dantly in the Jurassic series, the commonest genera being Coniopteris (fig. 716), Odontopteris (fig. 717), Sphenopteris, Cyclop- teris, Phlebopteris, Pecop- teris, Polypodites, Pachyp- teris, and Teniopteris. Endogens are by no means unknown in the Jurassic series, though no representative of the group of the Palms has been as yet detected. Amongst the most im- portant of the Oolitic Endogens may be men- l] il i i ria liv Fig. 716.—Coniopteris Murrayana. Great Oolite. 468 PALZOBOTANY. tioned the Aroideous fruit described by Mr Carruthers under the name of Aroides Stutterdi, and the fruits known as Podocarya and Kaidacarpum, both of which belong to the living order of the Pandanew (Screw-pines). Fig. 717.—Odontopteris cycadea. Lower Lias. Creraceous PLants. — The Lower Cretaceous Plants greatly resemble those of the Jurassic period, consisting mainly of Ferns, Cycads, and Conifers. The Upper Cre- taceous rocks, however, both in Europe and in North America, have yielded an abundant flora which resembles the existing vegetation of the globe in consisting mainly of Angiospermous Exogens and of Monocotyledons. In Europe, the plant-remains in question have been found chiefly in certain sands in the neighbourhood of Aix-la- Chapelle, and they consist of numerous Ferns, Conifers (such as Cycadopteris), Screw - pines (Pandanus), Oaks (Quercus), Walnut (Juglans), Fig (Ficus), and many Proteacew, some of which are referred to existing genera (Dryandra, Banksia, Grevillea, &e.) In North America, the Cretaceous strata of New Jersey, Alabama, Nebraska, Kansas, &c., have yielded the remains FLORAS OF SECONDARY AND TERTIARY PERIODS. 469 of numerous plants, many of which belong to existing genera. Amongst these may be mentioned Tulip-trees (Liriodendron), Sassafras (fig. 718), Oaks (Quercus), Beeches (Fagus), Plane- trees (Platanus), Alders (Alnus), Dog-wood (Cornus), Willows (Saliz), Poplars (Populus), Cypresses (Cupressus), Bald Cy- presses (Zazodium), Magnolias, &c. Besides these, however, there occur other forms which have now entirely disappeared from North America—as, for example, species of Cinnamo- mum and Araucaria. Fig. 718.—Cretaceous Angiosperms. a, Sassafras Cretaceum ; b, Liriodendron Meekii ; c, Leguminosites Marcouanus ; d, Salix Meckii. (After Dana.) The most important plant-remains of the American Cre- taceous rocks have, however, been obtained from a remark- able series of beds known as the “ Lignitic Formation,’ which is largely developed in the Western or Rocky Mountain region, and the precise geological position of which has been a subject of great controversy, and is still unsettled. In the Old World, as is well known, there is a great break between 470 PALZOBOTANY. the highest Cretaceous and the lowest Tertiary sediments— a break marked not only by a universal unconformity, but also by a great change in the characteristic fauna of the two deposits. On the other hand, in North America the highest unquestioned Cretaceous beds (the marine deposits of the Fox-Hills group) are succeeded by a great series of strata, well known as the Fort Union or Great Lignite series, the true stratigraphical position of which has been the subject of much dispute. These deposits consist of nearly four thousand feet of sandstones, shales, and beds of lenite, which rest quite conformably upon the unquestioned Cre- taceous deposits of the Fox-Hills group below, and which are succeeded unconformably by unquestioned beds of Ter- tiary age. In their lower portion they contain a number of marine organic remains, but these gradually disappear as we ascend in the series, and its upper portion is generally characterised by the remains of land and fresh-water shells, associated with a vast abundance of vegetable fossils, chiefly of the nature of detached Dicotyledonous leaves. The dif- ficulty of the problem as to the real age of this great and remarkable deposit arises chiefly from the fact that its marie fossils are fundamentally ‘of a Cretaceous type, whilst the remains of plants have an equally distinct Tertiary facies. Thus we find such characteristic Cretaceous Mollusca as TInoceramus, Ammonites, and Baculites, with unquestionable Dinosaurians (Agathawmas), side by side with a luxuriant flora of an essentially Tertiary aspect, comprising such mod- ern genera as Quercus, Acer, Populus, Ulmus, Morus, Fagus, Juglans, Alnus, Corylus, Ilex, Platanus, Ficus, Cinnamomum, Smilax, Laurus, Rhamnus, Magnolia, Eucalyptus, Thuja, Sequoia, Abies, Taxodium, Sabal, &e. Whilst this associa- tion of Cretaceous animals with Tertiary plants is undoubted, much difference of opinion obtains as to how it ought to be interpreted. On the one hand, high authorities, such as Dr Heer, and Professors Lesquereux and Dana, are of opinion that the plants ought to carry the day, and that the Lignitic Group ought to be considered as the base of the Tertiary series. On the other hand, equally high authorities, such as FLORAS OF SECONDARY AND TERTIARY PERIODS. 471 Meek, Hayden, Cope, and Stevenson, are of opinion that the fauna carries more weight than the flora, and that the Fort Union or Lignitic series should be regarded as truly the summit of the Cretaceous. To this view Prof. Newberry, who is in the rare position of having attained almost equal eminence in Paleeozoology and Paleeobotany, gives his ad- hesion ; and it is to be considered as in every respect the most probable view, if we take into account the fact that the disputed series is admittedly overlain unconformably by strata of undoubted Tertiary age. Upon the whole, then, when we take into consideration the general unreliability of terrestrial or fresh-water Mollusca as tests of age, and also the often unsatisfactory nature of stratigraphical conclusions based upon vegetable remains only, we can hardly avoid arriving at the opinion that the Great Lignitic series of North America is truly Cretaceous, though probably of a later date than any of the recognised Cretaceous deposits of the Old World. Admitting that the “ Lignitic Formation” of Western North America is truly of Cretaceous age, it follows that the Lower and Upper Cretaceous rocks are, from a botanical point of view, sharply separated from one another. The Paleeozoic period, as we have seen, is characterised by the prevalence of “ Flowerless” plants (Cryptogams), its higher vegetation consisting almost exclusively of Conifers. The Mesozoic period, as a whole, is characterised by the preva- lence of the Cryptogamic group of the Ferns, and the Gymno- spermic groups of the Conifers and the Cycads. Up to the close of the Lower Cretaceous, no Angiospermous Exogens are certainly known to have existed, and Monocotyledonous plants or Endogens are very poorly represented. With the Upper Cretaceous, however, a new era of plant-life, of which our present is but the culmination, commenced, with a great and apparently sudden development of new forms. In place of the Ferns, Cycads, and Conifers of the earlier Mesozoic deposits, we have now an astonishingly large number of true Angiospermous Exogens, many of them belonging to existing types; and along with these are various Monocotyledonous A? PALMOBOTANY. plants, including the first examples of the great and im- portant eroup of the Palms. It is thus a matter of interest to reflect that plants closely related to those now inhabiting the earth, were in existence at a time when the ocean was tenanted by Ammonites and Belemnites, and when land and sea and air were peopled by the extraordinary extinct Rep- tiles of the Mesozoic period. EocenE Piants.—The plants of the Eocene period ap- proximate on the whole to the existing vegetation of the earth. They are, however, in the main most closely allied to forms which now are found in tropical or sub-tropical regions. In the London Clay occur numerous fruits of Palms (Nipadites, fic. 719), along with various other plants, most of which indicate a warm climate as prevailing in the South of England at the commencement of the Eocene period. In the Eocene strata of North America occur numerous plants, such as palms, conifers, mag- Fig. 719.Nipadites ettipti. BOlia, cinnamon, fig, dog-wood, maple, cus, London Clay of Shep- hickory, poplar, plane-trees, &c. Upon ae the whole, the Eocene flora of North America is nearly related to that of the Miocene strata of Europe, as well as to that now existing in the American area. We may conclude, therefore, that “the forests of the American Eocene resembled those of the European Miocene, and even of modern America” (Dana). Miocene PLants—The deposits of the Miocene period have yielded an extraordinarily large number of plants, only a few of the more important of which can be indicated here. Our chief sources of information as to the vegetation of the Miocene period are derived from the Brown Coals of Germany and Austria, the Lower and Upper Molasse of Switzerland, and the Miocene strata of the Arctic regions. The lignites of Austria have yielded very numerous plant-remains, chiefly of a tropical character; one of the most noticeable forms being a Palm of the genus Sabal (fig. 720, B), now found in FLORAS OF SECONDARY AND TERTIARY PERIODS. 473 America. The plants of the Lower Miocene of Switzerland are also mostly of a tropical character, but include several forms now found in North America, such as a Tulip-tree (Liriodendron) and a Cypress (Zaxodium). Amongst the more remarkable forms from these beds may be mentioned Fan-Palms (Chamerops, fig. 720, A), numerous tropical ferns, 2 — 4 — ~~ A B 7 Fig. 720.—Miocene Palms. a, Chamcerops Helvetica; B, Sabal major. Lower Miocene of Switzerland and France. and two species of Cinnamon. The plant-remains of the Upper Molasse of Switzerland indicate an extraordinarily rank and luxuriant vegetation, composed mainly of plants which now live in warm countries. Among the commoner plants of this formation may be enumerated many species of Maple (Acer), Plane-trees (Platanus, fig. 721), Cinnamon-trees, and other members of the Lawracew, many species of Proteacew (Banksia, Grevillea, &e.), several species of Sarsaparilla (Smilax), Palms, Cypresses, &c. In Britain, the Lower Miocene (Eocene ?) strata of Bovey Tracy have yielded remains of Ferns, Vines, Fig, Cinnamon, Proteacee, &e., along with numerous Conifers. The most abundant of these last is a gigantic pme—the Sequoia Couttsic —which is very nearly allied to the huge Sequoia ( Welling- tonia) gigantea of California. A nearly-allied form (Sequoia Langsdor fir) has been detected in the leaf-bed of Ardtun in the Hebrides. In Greenland, as well as in other parts of the Arctic regions, Miocene strata have been discovered which have 474 PALAOBOTANY. yielded a great number of plants, many of which are identical with species found in the European Miocene. Amongst these plants are found many trees, such as conifers, beeches, oaks, maples, plane-trees, walnuts, magnolias, &c., Fig. 721.— Platanus aceroides. a, Fig. 722. — Cinnamo- Leaf; b, The core of a bundle of peri- mum polymorphum. a, carps; ¢, A single fruit or pericarp, Leaf; b, Flower. Upper natural size. Upper Miocene. Miocene. with numerous shrubs, ferns, and other smaller plants. With regard to the Miocene flora of the Arctic regions, Sir Charles Lyell remarks that “more than thirty species of Coniferee have been found, including several Sequoias (allied to the gigantic Wellinetonia of California), with species of Thujopsis and Salisburia, now peculiar to Japan. There are also beeches, oaks, planes, poplars, maples, walnuts, limes, and even a magnolia, two cones of which have recently been obtained, proving that this splendid evergreen not only lived but ripened its fruit within the Arctic circle. Many of the limes, planes, and oaks were large-leaved species ; and both flowers and fruits, besides immense quantities of leaves, are in many cases preserved. Among the shrubs are many ever- ereens, as Andromeda, and two extinct genera, Daphnogene and M<‘Clintockia, with fine leathery leaves, together with hazel, blackthorn, holly, loewood, and hawthorn. A species of Zamia (Zamites) grew in the swamps, with Potamogeton, Sparganium, and Menyanthes; while ivy and vines twined around the forest-trees, and broad-leaved ferns grew beneath their shade. Even in Spitzbergen, as far north as lat. 78° FLORAS OF SECONDARY AND TERTIARY PERIODS. 475 56’, no less than ninety-five species of fossil plants have been obtained, including Yaxodiwm of two species, hazel, poplar, alder, beech, plane-tree, and hme. Such a vigorous erowth of trees within 12° of the pole, where now a dwarf willow and a few herbaceous plants form the only vegetation, and where the ground is covered with almost perpetual snow and ice, is truly remarkable.” Taking the Miocene flora as a whole, Dr Heer concludes from his study of about 3000 plants contained in the Euro- pean Miocene alone, that the Miocene plants indicate tropi- cal or sub-tropical conditions, but that there is a striking intermixture of forms which are at present found in countries widely removed from one another. It is impossible to state with certainty how many of the Miocene plants belong to existing species, but it appears that the larger number are extinct. According to Heer, the American types of plants are most largely represented in the Miocene flora, next those of Europe and Asia, next those of Africa, and lastly those of Australia. Upon the whole, however, the Miocene flora of Europe is mostly nearly allied to the plants which we now find inhabiting the warmer parts of the United States; and this has led to the suggestion that in Miocene times the North Atlantic Ocean was dry land, and that a migration of American plants to Europe was thus permitted. This view is borne out by the fact that the Miocene plants of Europe are most nearly allied to the living plants of the eastern or Atlantic seaboard of the United States, and also by the occurrence of a rich Miocene flora in Greenland. As regards Greenland, Dr Heer has determined that the Miocene plants indicate a temperate climate in that country, with a mean annual temperature at least 30° warmer than it is at present. The present mit of trees is the isothermal which gives the mean temperature of 50° Fahr. in July, or about the parallel of 67° N. latitude. In Miocene times, however, the limes, cypresses, and plane-trees reach the 79th degree of latitude, and the pines and poplars must have ranged even further north than this. PLIOCENE PLANTS.—The vegetation of the Pliocene period 476 PALAOBOTANY. is, upon the whole, so closely allied to that now existing as to call for no special mention. It is worthy of notice, how- ever, that the Plocene flora of Europe was strikingly similar to that now existing in North America. Thus, we find in the Pliocene of Europe genera such as the Locust-trees (Robinia), the Honey - locusts (Gleditschia), the Sumach (Rhus), the Bald Cypress, (Taxodium), the Tulip-tree (Lirio- dendron), the Sweet-gum tree (Liquidambar), the Sour-gum tree (Nyssa), &c., which do not now occur in Europe, but are at present characteristic forms in the flora of temperate North America. GaLiO SS -Ak Yi: AppoMEN (Lat. abdo, I conceal). The posterior cavity of the body, contain- ing the intestines and others of the viscera. In many Invertebrates there is no separation of the body-cavity into thorax and abdomen, and it is only in the higher dAnnulosa that a distinct abdomen can be said to exist. ABERRANT (Lat. aberrvo, | wander away). Departing from the regular type. ABNORMAL (Lat. ad, from ; norma, a rule). Irregular; deviating from the ordinary standard. ABRANCHIATE (Gr. a, without ; bragchia, gill). Destitute of gills or bran- chie. ACANTHOPTERYGII (Gr. wkantha, spine ; pterux, wing). A group of bony fishes with spinous rays in the front part of the dorsal fin. ACARINA (Gr. akari, a mite). Leperditiade, i. 345. Lepidaster, i. 245, 251. Lepidechinus, i. 237. - Lepidesthes, i. 237. Lepidodendroids, ii. 434, 486, 437, 438, 457. Lepidodendron, ii. 435, 486, 437, 448, 444, 457, 458, 462. Lepidoganoids, ii. 134. Lepidophtotos, ii. oo Aes 457, 458. Lepidoptera, i. 407, 4 Lepidosiren, ii. 164, ie 168. Lepidosteide, ii. 133, 134, 135, 136, 142. Lepidosteus, ti. 111, 131, 135. Lepidostrobus, ii. 457. Lepidotide, ii. 136, 137. Lepidotus, ii. 137. Leporide, ii. 405. Lepratia, i. 428. Leptacanthus, ii. 159. Lepteenda, i. 452, 453, 455, 456. Leptarchus, ii. 394. Lepterpeton, ii. 181, 185. Leptocelia, i. 448. Leptodomus, i. 508, 509. Leptolepide, ii. 136, 137. Leptolepis, ii. 136. Leptomaria, ii. 29. Lepton, i. 499. Leptophleum, ii. 444. Leptoteuthis, ii. 90. Leptotherium, ii. 365. Lepus, ii. 405, 406. Leskia, i. 288. Lestornis, ii. 269. Lestosaurus, ii. 206, 207. Lichade, i. 371. Lichas, i. 356, 371. Lichenes, ii. 434. Lichenocrinus, i. 292. Licrophycus, ii. 441, 442. Lignitic Formation of North America, ii. 438. Lima, i. 475. Limacide, ii. 6, 44. Limacinide, ii. 48. Limade, i. 475. Limanomia, i. 4738. 519 Limestone, origin and microscopic struc- ture of, i. 17-20. Limnadia, i. 347, 350. Limneea, ti. 9, 44. Limneide, ii. 6, 44. Limnatornis, ii. 266. Limnocyon, ti. 400. Limnofelis, ii. 402. Limnohyidee, ii. 331. Limnohyus, ti. 332. Limnophis, ii. 199. Limnotheride, ii. 418. Limnotherium, ii. 418. Timea, i. 475. Limopsis, i. 486. Limoptera, i. 475. Limulus, i. 354, 357, 360, 361, 362, 380, 381, 382, 384, 385, 386. Lindstrémia, i. 211. Lingula, i. 435, 436, 437, 441, 461. Lingulella, i. 460, 461. Lingulide, i. 440, 442, 461. Liquidambar, ii. 476. Liriodendron, ii. 469, 473, 476. Litharca, i. 197. Lithentomum, i. 405. Lithistide, i. 142, 147-149. Lithocardium, i. 496. Lithodomus, i. 470, 483. Lithomantis, i. 406. Lithophis, ii. 199. Lithornis, ii. 266. Lithostrotion, i. 215. Lithothamnium, i. 20; Litogaster, i. 892. Littorina, ii. 21. Littorinide, ii. 5, 21. Lituites, ii. 66, 67. Lrtuola, i. 109, 111. Lituolida, i. 106, 111. Lntuolidea, i. 106. Lizards (see Lacertilia). Loftusia, i. 113. Lonsdaleia, i. 186, 215, 216. Lophiodon, ii. 330, 331. Lophiotherium, ii. 331. Lophobranchit, ii. 130. Lophohelia, i. 187, 190, 191. Lophopea, i. 419. Lophophyllum, i. 213. Loricata (Reptilia), ii. 189. Loricula, i. 338, 339, 340. Lozodon, ii. 380, 381. Loxomma, ii. 181, 184. Loxomylus, ii, 408. Loxonema, ii. 16, 17. Lucernarida, i, 153, 154. Lucina, i. 498. Lucinide, i. 469, 498. Lidia, i. 245, 252. Lumbricaria, i. 320. Lunulicardium, i. 497. Lunulites, i, 428, 429. Lutra, ii. 396. Lutraria, i. 504. Lutrictis, ii. 396. li. 482. 520 INDEX. Lycena, ii, 397. Meandropora, i. 433. Lychnocanium, i. 131, 132. Mecochirus, i. 392. Lycopodiacee, ii. 434, "435, 436, 437,444, Medustde, i. 154. 457. ‘Megacerops, ii. 333. Lycopodites, ii. 436, 444. Megaceros, ii. 361, 362. Lycosa, i. 402. Megachirus, i, 393. Lycosaurus, ii. 238, 239, Megalichthys, ii. 140, 142. Lymnocardium, i. 497. Megalocnus, ii. 305. Lyria, ii, 14. Megalodon, i. 501, 502. Lyrodesma, i. 486, 487. Megalomus, i. 487, 488. Lyropora, i, 423. Megalonyz, ii. 304. Lytoceras, ii. 82. Megalosaurus, li. 231, 234, 235. Megambonia, i. 487. Macacus, ii, 421. Megamys, ii. 408. Macellodon, ii, 205. Megaptera, i. 479. Macheracanthus, ii. 158. Megatherium, ii. 302. Machairodus, ti. 402, 403. Megerlia, i, 443. Maclurea, ti. 7, 24, 40. Megistocrinus, i. 278. Macrauchenia, ii. 335. Melania, ii. 19. Macrauchenide, ii, 335. Melaniade, 19, Lg: Macrocheilus, ii. 16. Melanopsis, ii. 19. Macrodon, i. 486. Meles, ii. 395. Macropetalichthys, ii. 151. Melide, ii. 359. Macropneustes, i, 243. Melina, i. 480. Macropodide, ii. 289. Melithea, i. 219. Macropoma, ii. 140. Mellivora, ii. 395. Macropus, ii. 295. Melobesia, ii. 431. Macrospondylus, ii. 211, Melocrinus, i. 278, 279. Macrotherium, ii. 300. Melolonthide, i. 407. Macrura, i. 391. Melonites, i. 235, 236, 237. Mactra, 1. 504, 505. Melosaurus, ii. 184. Mactride, i. 469, 504. Membranipora, i. 427. Madrepora, i. 197. Membraniporide, i. 425, Madreporide, i. 187, 196. Menocephalus, i. 368. Magas, i, 443. Menopoma, ii. 175, 177. Magnesian Limestone, i. 19, Merista, i. 446, 447. Magnotia, i. 233. Meristella, i. 446, 447. Malacodermata (Zoantharia), ii. 177. Merostomata, characters of, i. 380. Malacopteri, ii. 125. Merulina, i. 195. Malacostraca, i. 387. Merychyus, ii. 353. Malleus, i, 479, 480. Merycocherus, ii. 353. Malocystites, i. 290, 292. Merycodus, ii. 356. Mammalia, characters of, ii. 273-283; Merycopotamus, ii. 344. distribution of, in time, ii. 283; or- Merycotherium, ii. 357. ders of, ii. 286. Mesenteripora, i. 431. Mammoth, ii. 383, Mesodesma, i. 506. Man, ii. 421. Mesodon, ii. 138. Manatide, ii. 309. Mesohippus, ii. 338. Manatus, ii. 308, 309, 310. Mesolepis, ii. 139. Mandibles, of Cephalopods, ii. 54, 55. Mesonyz, ii. 400. Manis, ii, 300. Mesopithecus, ii. 421. Mantellia, ii. 467. Mesostoma, ui. 18. Mantide, i. 407. Mesotherium, ii. 406. Marginulina, i, 114. Metopias, ii. 184. Marshallia, i. 147. Metoptoma, ii. 32, 34. Mursipobranchii, ii. 120, 123. Metriophyllum, i. 211, Marsupial bones, ii. 288. Metriorhynchus, ii. 209, 211. Muarsupialia, characters of, ii. 287; dis- Meyeria, i. 392. tribution of, in time, ii. 290. Miamia, i. 406. » Marsupitide, i, 283, Michelinia, i. 200. Marsupites, i. 269, 271, 283, 284. Mierabacia, i. 194. Mastodon, ii. 378, "385. Micraster, 1, 242, 248. Muastodonsaurus, ii, 182, 184. Microconchus, i. 311, 314. Matheria, i. 502. Microdiscus, i. 354, 380, Mazonia, i. 402. Microlabis, 1. 402. Meandrina, i, 186, 193, Microlestes, ii, 284, 290, 291. INDEX. Micropholis, ii. 184. AMicrosolena, i. 195, 197, 198. Microsyops, ii. 418. Microtherium, ii. 350. Migrations, i. 41. Mitliola, i. 108, 110. M iliolida, i a 106, 108 Millepora, i. 170, 171, TUyPA, SED Millericrinus, i. 283. Miobasileus, ii, 333, Miohippus, ii. 338, 339. Mitra, ii. 13, 14. Moa, li. 258. Modiola, i. 483. Modiolopsis, i. 484. Mole, ii. 414. Mollusca, characters of, i. 410; shell of, i. 411, 412; distribution of, in time, i. 412, 413. Mollusca Proper, characters of, i, 413. Molluscoida, characters of, i, 413. Monera, i. 97, 98. Monocotyledons, ii. 430, 434, 435. Monodonta, ti. 27. Monograptus, i. 163, 164, 167. Monomerella, i. 463. Monomyary Bivalves, i. 469. Monoprionidian Graptolites, i, 167. Monopteria, i. 479. Monotis, i. 477, 478. Monotremata, characters of, ii. 286. Montacuta, i. 499. Monticulipora, i. 201, 425. Montlivaltia, i. 192. Moorea, i. 345. Mopsea, i. 219. Moropodide, ii. 301. Moropus, ii. 231. WMorosaurus, ti. 237. Morotherium, ii. 301. Mosasauride, ii. 205. Mosasaurus, li. 205, 206, 207. Moschide, ii. 357, 360. Moschus, ii. 357, 358. Motacilla, ii. 266. Mugilide, ii. 128. Muntjak, ii. 359, 360. Murenide, ii. 125. Murchisonia, ii. 27, 31. Murex, ii. 8. Muricide, ii. 5, 8. Muride, ui. 409. Musk-ox, ii. 369. Mustela, ti. 396. Mustelide, ii. 392, 395. Mutilata, ii. 308. Mya, i. 469, 506. Myacide, i. 469, 500. Myacites, i. 508. Myalina, i. 479. AMyarion, i. 410. Mycetes, ii. 419. Myliobatis, ii. 164, Myliusia, i. 147. Mylodon, ii. 303, 304. Mylothrites, i. 408, Or bo = Myocaris, i. 351. Myoconcha, i. 484. Myodes, ii. 410. Myogale, ii, 415. Myomorphus, ii. 305. Myophoria, i. 490, 491. Myopotamus, ii. 408. Myoxide, ii. 410. Myozus, ti. 410. Myrianites, i. 321, 322, 3238, 324. Myriapoda, characters ‘of, i. 402 bution of, in time, 1. 403. Myrmecobius, ii. 284, 289, 290. Myrmecophagide, ii. 305, "307. Mysarachne, ii. 415. MMysis, i. 390 Mysops, ii. 409. Mytilarca, i. 487. Mytilide, i. 468, 483. Mytilus, i. 469, 483. Naiadites, i. 509. Naresia, i. 420. Narica, ii. 15, 17. Nassa, ii. 11. Nasua, ii. 394, 395. Natatores, ii. 259. Natica, ii. 15. Naticella, ii, 15. Naticide, ii. 5, 15. Naticopsis, ii. 15, 17. Nautilide, characters of, ii. 58, 62, 63, 64, 66; “development of, il. 64, Gos distribution of, in time, ii. 64. Nautilus, ii. 58, 60, 63, 64, 66, 67. Nautilus, Pearly, il, 60; Paper, ii. 89. Necera, i. 507. Ne ebalia, i. 347, 349. Necrogammarus, i. 388. Necrolemur, ii. 417. Necrornis, ti. 265. Nematophores of Plumularians, i. 166. Nematoptychius, ii. 136. Nemertites, i. 817, 821, 322. Neolimulus, 1. 386. Neorinopsis, i. 407. Nereidavus, i. 316. Nereites, i. 317. Nerinea, ii. 17, 18. Nerita, ti. 25, 26. Neritide, ii. 5, 25. Neritina, ii. 26. Neritoma, ii. 26. Neritopsis, ii. 26. Nesodon, ii. 376. Ne europtera, i, 405, 406, 407, 408. Neuropteris, i. 437, 446, 452, 453, 463, 466. Nidulites, i. 128, 297, 298. Nileus, i. 375, 376. Niobe, i. 375. Nipadites, ii. 472. Nodosaria, i. 99, 101, 109, 114. Nodosinella, i. 100, 113. Neggerathia, ii. 437, 462, 463. Nonionina, i. 118. ; distri- 529 Nothoceras, ii. 72. Nothosaurus, ii. 221. Notidanus, ii. 154, 161. Notornis, ii. 262. Nototherium, ii. 295, 296. Nubecularia, i. 108. Nucleobranchiata (see Heteropoda), ii. Nucleocrinus, i. 304. Nucula, i. 488, 489. Nuculana, i, 489. Nuculanide, i. 485, 489. Nuculide, i. 485, 488. Nudibranchiata, ii. 6. Nullipores, i. 20; ii. 431. Nummutlina, i. 103, 118, 119, 120. Nummulinida, i. 106, 117, 118. Nummulitic Limestone, i. 17, 120. Nunmulitidea, i. 106. Nuthetes, ii. 205. Nyctilestes, ti. 413. Nyctisaurus, ii. 229. Nyctitherium, ii. 413. ‘ Nymphaline, i. 407, 408. Nyssa, ii. 476. Obolella, i. 461. Obolus, i. 460, 461. Oceanic Hydrozoa, i. 153, 154. Ochotherium, ii. 305. Octodon, ii, 408. Octodontide, ii. 407. Octopodide, ii. 57, 89. Oculina, i. 190. Oculinide, i. 178, 187, 190. Odontaspis, ii. 154, 162. Odontoceti, ii. 313. Odontolce, ii. 268. aie li. 452, 4538, 454, 467, 468. Odontopteryx, ti. 245, 253, 260. Odontor nithes, ii. 245, 253, 254, 268. Odontotorme, ii. 269. Odostomia, ii. 16. Ogygia, i. 355, 363, 374, 375. Oldhamia, i. 161, 162, 419, Olenide, i, 364. Olenus, 1. 356, 363, 366, 367. Oligocheeta, i. 309. Oligoporus, i. 236, 237. Oliva, ii. 11, 12, 138. Olivella, ii. 12. Ommastrephes, ii. 90. Omphyma, i. 209, 214. Onchus, ii. 154, 157, 1585 159: Oncidiade, ii. 6. Oniscus, i. "388. Onychodus, li. 144, Onychophora, i. 402, 403. Ooze, Atlantic, i. 15. Operculata, ii. iG 46. Operculina, i. 121. Ophiderpeton, ii. 179, 181, 182, 185. Ophidia, characters “of, ii. 198; distri- bution of, in time, ii, 199. Ophidioceras, li. 67. INDEX. Ophileta, ii. 24, 40, 41. Ophiocoma, i. 259 Ophioderma, i. 259. Ophioglypha, i. 255, 259. Ophiolepis, i. 259. Ophiomorpha, ti. 174. Ophiura, i. 256. Ophiurella, i. 259. Ophiuroidea, i. 225; characters of, i. 254-256 ; distribution of, in time, i. 256. Opis, i. 501, 502. Opisthobranchiata, Thess 3) Opisthococlia (Crotoditany iL 209, 213. Opossum, ii. 293, 298. Oppelia, ii. 83. Oracanthus, ii. 159. Orbiculoidea, i. 459. Orbitoides, i. 121. Orbitolites, i. 110. Orbitulidea, i. 106. Orbulina, i. 100, 115. Orchestia, i. 388. Oreaster, i. 252. Oreastride, i. 248, 249, 252. Oreodon, ii. 352, 353. Oreodontide, ii. 352. Oreopithecus, li. 421. Oreosaurus, ii. 207. Organic types, succession of, i. 90. Ormoceras, li. 69. Ormoxylon, ii. 436, 446. Ornithopterus, ii. 225, 229. Ornithorhynchus, ii. 286, 287. Ornithosauria, ii. 222, 228. Ornithoscelida, ii. 229. Orodus, ii. 159, 160. Orohippus, ti. 321, 337, 338. Oromery®, ii. 360. Orozoé, i. 344. Orthis, i. 452, 453, 454, 455. Orthisina, i. 452, 454. Orthoceras, i. 412; ii. 59, 69, 70. Orthoceratide, ii. 58, 69. Orthodesma, i. 484. Orthonema, ii. 16. Orthonota, i. 484. Orthoptera, i. 406, 407, 408. Ortonia, i. 311, 312, 3138. Osmeroides, ii. 125. Osteolepis, ii. 182, 140, 142. Ostraciontide, ii. 130. Ostracoda, characters of, i. 341, 342; distribution of, in time, i. 343. Ostracostet, ii. 134, 146. Ostrea, i. 469, 471, 472. Ostreide, i. 468, 471. Otaria, il. 393. Otodus, ii. 162. > Otozamites, ii. 467. Oudenodon, ii. 204, 222, 223. Ovarian capsules of Graptolites, i. 164. Ovarian pyramid of Cystideans, i. 288. Ovibos, li. 368, 369. Ovide, ii. 367. Ovis, ii. 367. INDEX. Ovulites, i. 115. Ovulitidea, i. 106. Ovulum, ii. 14. Oxyrhina, ii. 162. Pachydermata, ii. 318. Pachygonia, ii. 184. Pachynolophus, ti. 331. Pachypora, i. 200 Pachypteris, ti. 467. Pachyrhizodus, ii. 125. Pachyrisma, i. 501. Pachyteichisma, i. 146. Pachytheca, ii. 435, 443. Pachytherium, ii. 807. Paguride, i. 393. Pagurus, 1. 393. Palacmeea, ii. 34. Paleeachlya, ii. 431. Paleacis, i. 140, 195. Palearca, i. 487. Paloaster, i. 245, 249, 250. Palechinus, i. 234, 235. Paledaphus, ii. 170. Paleétus, ii. 267. Paleega, i. 389. Paleichthyes, ii. 168. Paleinachus, i. 394. Paleocaris, i. 390. Paleocaster, ii. 409. Paleocercus, ii. 267. Paleocetus, ii, 3138. Paleocherus, i. 346. Paleochorda, i. 319. Palcocoma, i. 250, 251. Paleocoryne, i. 157, 158. Paleocyclus, i. 188, 194, 214. Paleocystites, i. 290 Paleodiscus, i. 254. Paleogithalus, ii. 265. Paleojulus, i. 404. Palwolagus, ii. 406. Paleolama, ii. 356. Paleolemur, ii. 417. Paleolithic Man, ii. 423. Paleomanon, i. 144. Paleomephitis, ii. 396. Paleeomys, ii. 408. Palwoniscide, ii. 135, 136. Paleoniscus, ii. 135. Palwontina, i. 407. Paleontological Record, imperfection of, i. 56-70. Paleontological zones, i. 36, 37. Paleontology, definition of, i. 1. Palewonyctis, ii. 396. Paleophis, ti. 199. Paleophycus, i. 319; Paleopteris, ii. 452. Paleopyge, 1. 362. Paleoreas, ii. 365. Palcortyz, ii. 263. Paleoryz, ii. 365. Paleosaurus, ii. 212, 213. Paleosiren, ii. 175. Paleospalax, ii. 414. ii. 440, 441. 523 Palewospiza, ii. 266. Palcosyops, ii. 332. Paleotheride, ii. 333. Paleotherium, ii. 833, 334. Paleotragus, ii. 365. Paleotringa, ii. 261. Paleoxylon, ii. 461. Palanatina, i. 508. Palaplotherium, ii, 334. Palapteryx, ii. 2 Palaranea, i. 402. Palasteriade, i. 251. Palasterina, 1. 250. Palastreide, i. 191. Paleschara, 1. 425, 427, Pali (Corals), 1. 182. Palinurus, i. 393. Palmacites, ii. 462. Palmipes, i. 251, 252. Paludicellea, i. 419. Paludina, ii. 625. Paludinide, ii. 525, Pandanee, ii. 468. Pandanus, ii. 468. Panolaz, ii. 406. Panopea, i. 506, 507. Paolia, i. 406. Paper Nautilus, ii. 56. Papyridea, i. 496. Parabolina, i. 365. Paradoxide, i. 363, 364. Paradoxides, i. 354, 356, 363, 364, 365, 366. Parahyus, ii. 347. Paramuricea, i. 217. Paramys, ii. 411. Parapholas, i. 511. Parka, i. 382. Parkeria, i. 118, 156. Pasceolus, i. 128, 297, 298. Passeres, ii, 265. Patella, ii. 2, 82, 34. Patellide, ii. 533. Patinella, i. 431, 482. Pauropoda, i. 402, 403. Pauropus, i. 403. Pavonaria, i. 219. Pearly Nautilus, ii. 56. Peccary, ii. 345, 346, 348. Pecopteris, ii. 437, 446, 452, 453, 463, 466, 467. Pecten, i. 469, 473, 474. Pectinaria, i. 310. Pectinated rhombs of Cystideans, i. 289, 290, Pectinide, i. 473. Pectunculus, i. 486. Pedicellinec, i. 419. Pedipalpt, i. 399. Pedunculated Cirripedes, i. 335, 337. Pelagornis, ii. 261. Pelagosaurus, ii. 209, 211. Pelecorapis, ii. 125. Pelion, ii. 177. Pelonaz, ii. 348. Peltarion, ii. 26. 524 Peltastes, i, 233. Peltocaris, i, 347, 348, 349, Peltoceras, ii. 83. Pen, of Cuttle-fishes, ii. 55, 88. Peneroplidea, i. 106. Peneroplis, i. 108, 110, Pennatulide, i. 219. Pentacrinide, i. 282. Pentacrinus, 1. 267, 268, 271, 282, 283. Pentalophodon (Mastodon), ii. 387. Pentamerella, i. 452. Pentameride, i. 440. Pentamerus, i. 459, 451. Pentatremites, i. 304. Pentremites, i. 299, 300, 301, 304. Perameles, ii. 289, 298. Peratherium, ii. 293. Percherus, ii. 347. Percide, ii, 128 Perdicide, li. 262. Perennibranchiata (Amphibia), i. 174, 175. Perforata (Foraminifera), i. 99, 106, 113 ; (Zoantharia), i. 180, 188 ; char- acters and distribution, i. 195; families of, i, 196-198. Periaster, i. 248. Pericosmus, i, 243. Peridinium, i. 98. Periechocrinus, i. 278, Perigonimus, i. 155. Pervpatus, i. 408. Perischodomus, i, 237. Perischoechinide, i, 230, 234. Perisphinctes, ii. "83. Perissodactyla, ii. 319. Perna, i. 479, 480, 481. Pernopecten, i. 474. Pernostrea, i. 472. Peronella, i. 136. Peronosporites, ii. 433. Petalodonts, ii. 160. Petalodus, ii. 159, 160. Petraia, i. 189, 212. Petraster, i. 250, Petricola, i. 504. Petrodus, ti. 154. Petrospongiade, i. 136. Pezophaps, ii. 263, 264. Phacopide, i. 363, 368. Phacops, i. 353, 354, 355, 363, 3868, 369. Phaedra, i. 389. Phalangide, i. 399, 401. Phalangistide, ii, 289, Phanerogams, ii. 429. Phaneropleurini, li. 140, 145. Phaneropleuron, ii. 140, 142, 145. Pharyngobranchii, li, 120, 123. Phascolomys, ti. 289, 294. PF cscolotherum.: ii. 284, 291, 293. Phasianella, ii. 27, 28. Phasianide, ii, 262. Phillipsastrea, i 210, 215. Phillipsia, i. 363, 370, 371. Phimocrinus, i. 282. Phlebopteris, ti. 467. INDEX. Phocide, ii. 392, 393. Pholadide, i. 469, 510. Pholadomya, i. 509. Pholas, i. 470, 510. Pholiderpeton, ii. 184. Pholidogaster, ii. 181, 184. Pholidosaurus, ii. 209, 212. Phormosoma, i. 234. Phorus, ii. 22, 23. Phosphate of Lime, i. 20, 21. Phragmoceras, ii. 69, 71. Phrynus, i. 400, 401. Phylactoleemata, i i, 419. Phyllidiade, ii. 6. Phylloceras, ii. 82. Phyllodocites, i, 317, 321, 322 Phyllograptus, i. 170, 171. Phyllopoda, characters of, i. 346; dis- tribution of, in time, i. 345, Phyllopora, i. 421, Piyllosoma, i. 392. Phyllostomide, ii. 412. Phyllostoma, ii, 413. Phylloteuthis, ii. 90. Physa, ii. 7, 45. Physeter, ii, 314. Physeteride, ii. 314 Phy ysophoridee, th 153, 154, 168. Physostomata, ii. 125. Phytopsis, ii, 441, Picus, ii. 265. Pierine, i. 408. Pileolus, ii, 26. Pileopsis, ii. 33. Pinacoceras, ii. 82. Pinites, ii, 434, 461. Pinna, i. 469, 482. Pinnide, i, 482. Pinnigrada, ii. 391, 392. Pinnipedia, ii. 391. Pinnularia, ii. 448. Pisania, ii. 9. Pisces, characters of, ii.109-119; orders of, il. 124; distribution of, in time, ii. 119. Pisidium, 409! Pistosaurus, i, 221. Placodus, iz, 22). Placoganoids, ii. 134, Placoidei, ti, 110. Placoid scales, ii. 110, Placoparia, i. 377. Placuna, i, 473. Placunopsis, i. 473. Plagiaulaz, ii. 284, 292, 293 Plagiostoma, i, 475. Plagiostomi, ti, 153, 156. Planolites, i. 320. Pilanorbis, ii. 45. Planorbulina, i. W7. Plantigrada, ii. 391, 393. Plasmopora, i. 222. Platanus, ii. 469, 473, 474. Plataz, ii, 129. Platephemera, i. 405. Platyceras, ii. 33. Platycrinide, i. 278. INDEX. Platycrinus, i. 263, 268, 278, 279. Platygnathus, ti. 140. Platygonus, i. 348. Platyostoma, ii. 21. Platyrhina, ii. 419. Plectognathi, ii. 127. Plectrodus, ii. 158. Plesiarctomys, ii. 411. Plesiosauria, ti. 218. Plesiosaurus, ii. 218, 219, 220, 221. Plesiosorex, ii. 415 Plesioteuthis, ii. 95. Pleuracanthus, ii. 163. Pleuraster, i. 252. Pleurobranchide, ii. 637. Pleurocystites, i. 287, 294. Pleurodictyum, i. 195. Pleurodont Lizards, ii. 201. Pleuronectes, development of tail of, ii. Le Ls: Pleuronectide, ii. 127. Pleurope, i. 146. Pleurophorus, i. 502, 503. Pleurorhynchus, i. 497. Pleurotoma, ii. 12, 13. Pleurotomaria, ii. 27, 29, 30. Plicatula, i. 476. Pliohippus, ii. 339. Pliolophus, ii. 331. Pliopithecus, ii. 420. Pliosaurus, li, 221, 222. Plocoscyphia, i. 146. Plumaster, i. 245, 252. Plumutites, i. 339. Plutonia, i. 364. Pocillopora, i. 191, 198. Podocarya, ii. 468. Podocyrtis, i. 131, 132. Podophthalmata, i. 387, 389. Podozamites, ti, 438, 466. Poébrotherium, ii. 356. Pecilasma, i. 334, 340. Pecilopoda, i, 384. Poikilopleuron, ii. 231. Polacanthus, ii. 231. Polir-schiefer, i. 21. Pollicipes, i. 340. Polycelia, i, 211. Polycope, i. 346. Polycyphus, i. 233. Polycystina, i. 98, 130-152. Polymorphina, i. 109, 114. Polymorphinide, i. 106. Polypodites, ii. 467. Polypora, i. 421, 423. Polyprotodontia (Marsupialia), ii. 289. Polypterini, ii. 140, 141. Polypterus, ii. 133, 140, 141, 142. Polystomella, i. 102, 118. Polystomellidea, i. 106. Polytrema, i. 117. Polytremuacis, i. 222. Polytremarza, ii. 29. Polyzoa, characters of, i. 414-419; or- ders of, i. 419; distribution of, in time, i. 419, 420. 525 Populus, ii. 469. Porambonites, i. 450. Porcellana, i. 393. Porcellia, i. 30. Porites, i. 197. Poritida, i. 187, 195, 197, 198, 199. Porocidaris, i. 226, 231. Poromya, i. 507. Porosphera, i. 172. Portheus, ii. 126. Posidonomya, i. 477. Potamides, ti. 17. Potamotherium, ii. 396. Poteriocrinide, i. 273. Potertocrinus, i. 273, 274. Pothocites, ii. 435, 437, 462. Prearcturus, i. 389. Prasopora, i. 202. Prestwichia, i. 385, 386. Primitia, i. 344, 345. Primnoa, i. 217. Prionastrea, i. 193. Priscodelphinus, ii. 314. Pristerodon, ii. 205. Pristiphoca, ii. 393. Proboscidea, characters of, ii. 378. Proboscis, of Crinoids, i. 264. Procelia (Crocodilia), ii. 209, 210. Procamelus, ii. 356, 357. Procervulus, ti. 359. Procyon, ti. 394. Producta, i. 456, 457, 458. Productelia, i. 458. Productide, i. 440, 441, 456. Proetide, i. 369. Proetus, i. 354, 363, 370, 371. Promephitis, ii. 396. Prongbuek, ii. 364. Propaleotherium, ii. 331. Propora, i, 222. Prorastomus, ii. 310. Prosimic, ii. 417. Prosobranchiata, ii. 5, 7. Prosoponiscus, i. 388. Protachilleum, i. 144. Protarea, i. 195, 197. Protaster, i, 249, 255, 256, 258. Proteacee, ii. 468, 473. Protemnodon, ii. 295. Protichnites, i. 360, 361. Protocystites, i. 292. Protohippus, ii. 339. Protolabis, ii. 356. Protolycosa, i. 40. Protomeryz, li. 356. Protopithecus, ii. 419. Protoptert, li. 164. Protopteris, ti. 446. Protornis, li. 265. Protorosaurus, ii. 202. Protoseris, i. 194. Protospongia, i. 134. Protostigma, ii. 435, 443. Prototaxites, ii. 436, 446, 448. Protovirgularia, i. 219. 526 INDEX. Protozoa, characters of, i. 97 ; divisions of, i. 97; distribution of, in time, i. 98. Protriton, ii. 175, 177. Proviverra, ii. 396. Prunocystites, i. 294. Psaimmobia, i. 505. Psammodus, ii. 158, 159. Psaronius, ii. 436, 437, 446, 452. Pseudelur US, li. 402, Pseudocrinus, i. 287, 294. Pseudocyon, ii. 399. Pseudodiadema, i. 232. Pseuodofungide, i. 194. Pseuodomonotis, i. 478. Pseudoneuroptera, i, 405, 407. Pseudoniscus, i. 383, 384, Pseudoscorponide, i. 399, 402. Pseudoturbinolide, i. 190, Psilocephalus, i. 375. Psilophyton, ii. 435, 444, 445, 446. Psittacide, ii. 265, Psolus, i. 305. Pteranodon, ii. 223, 229. Pteranodontia, ii. 229. Pteraspis, ii. 120, 126, 147, 148, 157. Pterichthys, ii. 115, 126, 147, 149. Pterinea, i. 478, 479. Pterocaris, 1. me 349, Pteroceras, ii. 7, 8 Pterodact ylus, i ii. 224, 226, 228. Pierodon, ii. 400. Pteronites, i. 479. Pteropernd, i. 479. Pterophyllum, ii. 488, 462, 466, £67. Pteropide, ii. 412. Pteroplax, ii. 181, 184. Pteropoda, characters of, ii. 47 ; orders of, 248 ; distribution of, in time, ii. 48. Pterosauria, ii. 190, 222-229, Pterostoma, ii. 24. Pterotheca, ii. 48, 49, 50. Pterygotus, Als 381, 382, 383. Pitilodictya, i. 493, 424, Ptilograptus, 1. 161, 162. Ptilonaster, 1. 255, 256, 257. Ptilopora, i. 421, 422. Ptychoceras, li. 59, 75, 85, 86. Ptychodus, ii. 160, 161. Ptyctodus, ii, 155. Pugiunculus, ii. 49. Pulimonifera (Gasteropoda), ii. 2, 6, 41. Pulvinulina, i. 116. Pupa, ii. 7, 42, 48, 44, Purpura, ii. 11. Purpurina, ii. 10. Pustulopora, i. 430. Pycnodontide, ii. 137. Pycnodus, ii. 138. Pygaster, i. 238. Pygaulus, i. 240. Pygocephalus, i. 390, Pygopterus, ii. 135. Pygurus, i. 241, Pyramidella, ii. 16, 17. Pyramidellide, ii. 5, 15. Pyrgia, i. 204, 205. Pyrgoma, i. 337. Pyrina, i. 240. Pyrula, ii. 9, 11. Python, ii. 198, 199. Pythonomorpha, ii. 206. Quadrumana, ii. 416. Quenstedtia, 1. 505. (Juercus, ii. 468, 469. Quinqueloculina, i. 108, 109. Quoyia, ii. 18 Radiata, i. 152. Radiolaria, i. 97; characters of, i, 129; distribution of, in time, i. 130. Radiolites, i. 494, 495. Radula, i. 475. Raia, i. 168. Ranella, ii. 9. Raniceps, ii. 181. Raphiosaurus, ii. 205. raphistoma, ii. 24, 30. Raptores, ii. 266. Rasores, ii. 262. Rastrites, i. 163, 169. Ratite, ii. 254, 255. Rays, i. 163. Receptaculites, i. 126-128, 297, 299. Red Coral, i. 219. Reef-building Corals, i. 187. Regular Echinoids, i. 230, 237. Reindeer, ii. 361. Remopleuride, i. 364. Remopleurides, i. 364. Rensseleria, i. 4438. Reptilia, characters of, ii. 187; orders of, ii. 190; distribution of, in time, ii. 190. Requienia, i. 492, 493, Retepora, i. 420, 429. Retiolites, i. 163. Retzia, i. 446, 447. Rhabdocidaris, i. 236. Rhabdoidea, i. 106. Rhabdolepis, ii. 135. Rhabdomeson, i. 424, 425. Rhabdophora, i. 162. Rhabdopleura, i. 163. Rhabdopleurea, i. 419. Rhamphastide, ii. 265. Rhamphorynchus, ii, 223, 229. Rhea, ii. 259. Rhinoceride, ii. 322. Rhinoceros, li. 320, 322, 823, 324, 325, 326, 327, 328. . Rhinolophide, ii. 412. Rhinolophus, ii. 413. Rhinosaurus, ii. 182, 184. Rhizocarpee, ii. 434, Rhizocrinus, i. 260, 261, 269, 283, 289. Rhizodopsis, ii. 142, 144. Rhizodus, ii. 140, 142, 144. Rhizopoda, i. 197. Rhizostomide, i. 154, Rhodarea, i. 198. ——_—. ~* INDEX. 527 Rhodocrinide, i. 274. Rhodocrinus, i. 274. Rhodophyllum, i. 216. Rhoechinus, i. 237. Rhombina, i. 346. Rhombus, ti. 127, 128. Rhopalastrum, i. 132. Rhus, ii. 476. Rhynchocephalia, ii. 204. Rhynchocett, ii. 313, 314. Rhynchodus, ii. 154, 155. Rhyncholites, ii. 55. Rhynchonella, i. 441, 449. Rhynchonellide, i. 438, 440, 441, 442, 449, 450. Rh ynchosaurus, li. 202, 204, 222. Rhynchoteuthis, ii. 55. Rhytidolepis, ii. 459, 461. Rhytina, ii. 310, 311, 312. Ribeiria, i. 351. Richmond Earth, i. 23; ii. 480, 431. Rimula, ii. 31, 32. Ringicula, ii. iD, 12. Rissoa, ii. 21, 24, 25s Rissoina, ii. 24, Robinia, ii. 476. Robulina, i. 101, 114. Rocks, definition of, i. 8; classification ofen 9: Rodentia, ii. 404. Roebuck, ii. 361. Rostellaria, ii. &, 9. Rotalia, i. 102, 109, 116. Rotalidea, i. 106. Rudistes, i. 493. Rugosa, i. 153, 154; characters of, i. 206-210 ; families of, i. 210-218. Ruminantia, ii. 318, 353. Rupicapra, ii. 365. Rusichnites, i. 361. Rusophycus, i. 361. Sabal, ii. 470, 473. Sabella, i. 310. Sabellaria, i. 310. Saccammina, i. 112, 113. Saccosoma, i, 265, 266, 285. Sagenaria, ii. 443, 458. Salamander, ii. 175. Salenia, i. 230, 233. Saleniade, i. 231, 233. Salicornaria, i. 427, 428. Salicornariade, i. 427, Salix, ii. 469. Salmonide, ii. 125. Salterella, ii. 50. Sanguinolaria, i. 506. Sanguinolites, i. 509. Sao, 1. 357, 360, 3638, 365, 368. Sassafras, ii, 469. Saturniide, i. 407. Satyride, i. 408. Satyrine, i. 407. Sauranodon, ii. 216. Sauranodonta, ii, 216. Sauria, ii. 201. Saurillus, ii. 205. Saurocephalus, ii. 126. Saurocetes, ii. 317. Saurodipterini, ii. 140, 142. Sauropoda, ii. 237. Sauropterygia, i. 190, 218-222. Saurornithes, ii. 254, 267, 268. Saurosternon, ti. 205. Saurure, ii. 254, 267, 268. Saxicava, i. 506, 507. Scalaria, ii. 4, 19, 20, Scalariade, ii. 20. Scales of Fishes, ii. 109. Scalide, ii. 20 Scalites, ii. 30. Scalpellum, i. 340, Scansores, ti. 264. Scaphaspts, ii, 148. Scaphites, li. 75, 84, 85. Scapirhynchus, ii. 132. Scelidotherium, ii. 304. Schistopleurum, ii. 306, 307. Schizaster, i. 243. Schizodus, i. 490, 499. Scissurella, ii. 27, 28 Scturavus, ii. 411. Sciuride, ii. 411. Sciurus, ii. 411. Selerobasica (Zoantharia), i. 178. Sclerodermata (Zoantharia), i. 179. Sclerogenidee, ii. 128. Scolecida, i. 224. Scolithus, 1. 318. Scomberide, ii. 128. Scorpion, i. 400. Scorpionide, i. 399, 402. Scrobicularia, i. 506. Scrupocellaria, i. 427, 428. Scutella, i. 228, 241. Sea-anemones, i. 177. Sea-cucumbers, i. 305. Sea-urchins, i, 226. Seals, ii. 392. Sedimentary rocks, origin of, i. 12. Selachit, ii. 156, 161, Selenaria, i. 429, Selenariade, i. 429. Selenodonta (Artiodactyla), i. 341. Semele, i. 506. Semnopithecus, ii. 420, 421. Sepia, ii. 56, 90. Sepiade, ii. "58, 59, 88, 90. Septa, of corals, i 181, 182, 183, 184; of the shell of "Tetrabranchiate Cepha- lopods, ii. 62, 63. Septastraa, i. 193. Sequoia, ii. 478, 474. Seraphs, ii. 8. Seriatopora, i. 191, 198. Serpula, i. 310, 311, 314, 315. Serpulites, i. 310, 313. Sertularida, characters of, i. 158 ; dis- tribution of, in time, i. 159. Sessile Cirripedes, i, 335. Sharks, ii. 161. Shrew-mice, ii. 415. 528 INDEX. Shumardia, i. 380. Sieboldia, ti. 177. Sigaretus, ii. 15, 17. Sigillaria, ii. 436, 446, 448, 459, 460. Sig nanos, ii. 434, 437, 438, 443, 446, 459. Silicification, i. 5, 141. Silicispongice, i. 140. Siliquaria, ii. 20. Siluride, ii. 125, 126. Simoceras, ii. 83. Simocyon, i. 399. Simosaurus , ii. 221. Sinupalliaha 469. Siphonia, i. 148, 149. Siphonida (Lamellibranchiata), i. 468, 2. Siphonostomata (Gasteropoda), ii. 5, 7-14. Siphonotreta, i. 460. Siren, ii. 175. Sirenia, ii. 308. Sirenoidei (Dipnort), ii. 168. Sivatherium, ii, 366, 367. Slimonia, i. 381, 382, 383. Sloths, ii. 300, 305. Smilax, ti. 470, 473. Solanocrinus, i. 265, 285. Solarium, ii. 21, 22. Solaster, i. 245, 248, 251, 252. Solecurtus, i. 506. Solemya, i. 499. Solen, i. 506. Solenide, i. 469, 506. Soleniscus, ii. 16. Solenopsis, i. 506. Solidungula, ii. 318, 335. Solipedia, ii. 318, 335. Solitaire, ii. 263, 264. Sorex, ii. 415. Soricide, ii. 414. Sowerbyia, i. 505. Spalacotherium, ii. 284, 292, 293. Spatangide, i. 238, 241, Spatangus, i. 243. Spathobatis, ii. 164. Spatularia, ii. 132, 151. Spermophitlus, ii. 411. 3 Spheractinia, i. 156. Spheerexochus, i. 376, 377. Spheerococcites, ii. 443, Spheeronites, i. 293, 297. Spherospongia, i. 128, Sphagodus, ii. 154, 157. Sphenaulaz, i. 145. Sphenodon, ii. 203, 204. Sphenodus, ti. 162. Sphenophyllum, li. 435, 444. 297, 298, 299. Sphenopteris, ii. 437, 446, 447, 452, 454, 467. 463, Sphenothallus, ii. 441. Sphenotrochus, 1. 187. Spirangium, ii. 462. Spirifera, i. 437, 440, 445. Spiriferide, i. 440, 441, 444, 447, 448. Spiriferina, i. 445. (Lamellibranchiata), i. Spirigera, i, 446, 447. Spirillina, i. 115. Spirillinidea, i. 106. Spirophyton, li. 443. Spirorbis, i. 310, 311, 313, 314. Spirula, ii. 55, 88. Spirulide, ii. 58, ale Sptrulirostra, i. 90, 91. Spondylide, i. 475. Spondylus, i. 475. Spongida, characters of, i. 132; distri- bution of, in time, i. 133-149. Spongilla, i. 134. Spongillopsis, i. 134. Sporadopyle, i. 145. Squalodon, ii. 315, 316, 317. Squaloraia, ii. 164. Squamata (Reptilia), ii. 189. Sqguamulinidea, i. 106 Squatina, ii. 161 Squilla, i. 390. Stacheia, i. 113. Stagonolepis, ii. 190, 209, 211. Stauractinella, i. 146. Stauria, i. 208, 209, 210. Stauride, i. 210, 211. Staurocephalus, i. 377. Stauroderma, i. 146. Staurodermide, i. 146. Steganodictyum, i. 144. Stegodon, ii. 382. Stellaster, i. 252. Stemmatopteris, ii. 446, 452. Stenaster, i. 249. Steneosiber, ii. 409. Steneosaurus, ii. 209. Stephanastrum, i. 132. Stephanoceras, ii. 83. Stephanophyllia, i, 196. Stereodelphis, ii. 314. Stereognathus, ii. 284, 291. Sternbergia, i. 448, 462. Sthenurus, ii. 295. Stigmaria, ii. 436, 446, 460, 461. Stomapoda, characters of, i. 389; dis- tribution of, in time, i. 390. Stomatella, ii. 27 Stomatia, ii. 28. Stomatopora, i. 204. Stomechinus, i. 233. Straparollina, ii. 24. Straparolus, li. 24. Strata, contemporaneity of, i. 38. Stratodus, ii. 125. Streblopteria, i. 475. Strepsirhina, ii. 416. Strepsodus, li. 142. Streptelasma, i. 213. Streptorhynchus, i. 452, 455, Streptospondylus, ii. 213. Striatopora, i. 200, 201. Stricklandinia, i. 451. Stringocephalus, i. 443. Strobilocystites, i. 291. Stromatopora, 1. 137-139, 156, 172. Strombidea, ii. 5, 7. INDEX. 529 Strombodes, i. 214, 215. Strombus, ii. 7. Strophalosia, i. 458. Strophodus, ii. 160, 161. Strophomena, i. 452, 453, 454, 455 Strophomenidee, i. 440, 441, 452, Struthio, ii. 255. Struthionide, ti. 255. Sturionide, ii. 150. Stygina, i. 375. Stylarcea, i. 197. Stylaster, i. 173, 191. Stylasteride, i. 172, 217. Stylinodon, i. 375. Stylinodontide, ii. 373, 375. Styliola, ii. 49. Stylodictya, i. 182. Stylonurus, i. 382, 383. Subulites, ui. 11, 12. Succession of Organic Types, i. 90-94. Suessia, i. 446. Suida, ii. 344. Sulcana, i. 346. Sulcator, burrows of, i. 325. Sulphate of Lime, 1. 21, Sus, ii. 844, 345, 346. Syllemus, ui. 128. Symbathocrinus, i, 282. Symborodon, ii. 833. Synapta, i. 3065. Syngnathide, ii. 180. Synhelia, i. 190. Synocladia, i. 421. Syringopora, i. 203, 204, 205. Syringothyris, i. 446. Syringoxylon, ii. 436. Tabule, i. 183. Tabulata, i. 188; characters and distri- bution of, in time, i. 198; families of, i. 199-204. Teeniaster, i. 249, 255. Teeniopteris, ii. 467. Talitrus, i. 388. Talpa, ii. 414. Talpavus, ii. 414. Talpide, ii. 414. Tancredia, i. 505. Tapes, i. 504. Tapravus, ii. 331. Tapiride, ii. 329. Tapirus, li. 329, 330. Taxocrinide, i. 275. Taxocrinus, 1. 275. Taxodium, ii. 469, 470, 473, 475, 476. Taxodon, li. 396. Tectibranchiata, ii. 5, 36. Teleidosaurus, ii. 209. Teleodactyla ( Ungulata), ii. 319, 321. Teleosaurus, li. 209, 211, 212. Teleostei, characters of, ii. 124; distribu- tion of, in time, ii. 124; sub-orders of, ii. 125-1 Telerpeton, ii. 190, 202, 203. Tellina, i. 505. Tellinidee, i. 469, 505. Viol. i: Tellinomya, i. 486, 489. Telmatolestes, ii. 419. Telmatornis, ii. 261. Temnechinus, i. 233. Tentaculites, i. 312; ii. 48, 51. Teratosaurus, i. 231. Terebra, ii. 11. Terebratella, i. 488, 442, 443. Terebr atula, i. 438, 489, 442. Las atulide, i. "439, 440, 441, 442, 443. Terebratulina, i. 442. Terebrirostra, i. 443. Teredo, i. 511. Tesselata (Crinoidea), i. 271. Testacella, ii. 44. Testudinide, ii. 196, 197. Testudo, ii. 198. Tetrabranchiata, characters of, il. 57, 59; shell of, ii. 62; distribution of, in time, ii. 58, 63. Tetradecapoda, i. 387. Tetradium, i. 204. Tetragonis, i. 128. Tetragonolepis, ii. 136, 137. Tetragraptus, i. 168. Tetralophodon (Mastodon), ii. 386. Tetraonide, ii. 262. Tetraprionidian Graptolites, i. 170. Tetraprotodon, ii. 342. Teudopsis, ii. 89. Teuthide, ii. 57, 59, 89. Textilaridea, i. 106. Textularia, i. 115, 116. Thalaminia, i. 156. Thalassicollida, i. 131. Thallogens, ii. 429. Thamnastr ced, i. 193. Thamnograptus, 1. 16. Theca, ii. 48, 49. Thecaphora, i. 153, 158. Thecia, i. 202 Thecide, i. 202. Thecidiide, i. 440, 442, 448. Theeidium, i. 444. Thecocyathus, i. 189. Thecodontia, ii. 212. Thecodontosaurus, ii. 212. Thecosmilia, i. 192, 193. Thecosomata (Pteropoda), ii. 48. Thelodus, ii. 154, 158. Thelyphonus, i. 400, 401. Theonoide, i. 433. Ther iodontia, ii. 190, 238, 239. Thetis, i. 506, 507. Thinning out of beds, i. 66-68. Thinohyus, ii. 348. Thinolestes, ii. 418. Thlipsura, i. 346. Thoracica (Cirripedia), i. 335. Thoracosaurus, ii, 209, 210. Thracia, i. 509. Thylacinus, ii. 289, 298. Thylacoleo, ii. 296, 297. Thysanura, i. 408. Tigrisuchus, ii. 239. bo fe 530 Tillodontia, ii. 373. Tillotheride, ii. 373. Tillotherium, ii. 373, 374. Tinoceras, ii. 373. Tinoporus, 1, LOS Mie Titanomys, i. 406. Titanophis, ii. 199. Titanosaurus, ii. 231, 234. Titanotherium, ii, 333. Tornatella, ii. 36. Tornatellide, ii. 6, 36. Tortoises, ii. 196, 197. Toxoceras, ii. 83. Toxodon, ii. 375, 376. Toxodontia, ii. 375. Trachyderma, i. 311, 313. Trachynemide, i. 154. Tracks, of Annelides, i. 317, Tragoceras, li. 365. Tragulide, ii. 350, 452, 357. Tragulus, ii. 357, 358. Trapexium, i. 500. Tremabolites, i. 146. Tr emadictyon, i. 145. Tremanotus, ii. 40. Trematis, i. 459, 460. Trematodiscus, 1. 132. Trematopora, i. 424, 425. Trematosaurus, ii. 184. Tretenterata, Aig 440. Tretoceras, ii. 70. Triacrinus, i. 277. Triarthrus, i. 356, 368. Trichecide, ii. 393. Trichecodon, ii. 393. Trichecus, ii. 393. Trichites, i. 83. Trichotaster, i. 251. Trichotropis, li. 9. Triconodon, ii. 284, 292, 293. Tridacna, i. 495, 496. Tridacnide, i. 469, 495. Trigonellites, ii. 75, 81. Trigonia, i. 490. Trigoniade, i. 468, 490. Trigonocarpon, ii. 461. 320-326. Trigonosemus, i. 443. Trilolita, characters of, i. 851-362; dis- 362, 363; tribution of, in time, i. families of, i. 363-380. Trilophodon (Mastodon), ii. 368. Trimerella, i. 462. Trimerellide, i. 440, 462. Trimerocephalus, i. 368. Trinucleide, i. 363, 372. Trinucleus, i. 373. Trionycide, ii. 196, 197. Trionyz, ii. 197. Triplesia, i. 449. Tripoli, i. 23. Tristichopterus, ii. 140, 141, 142. Triton, i. 9. Torchammina, i. 112. Trochobolus, i. 146. 448, 449, 450, 460, 353, 354, 362, 363, 372, INDEX. Trochoceras, li. 66, 67. Trochocyathus, i. 190. Trochocystites, i. 290, 292. Trocholites, ii. 68. Trochosmilia, i. 192. Trochotoma, ii. 30. Trochus, ii. 27, 28. Trogontherium, ii. 409. Trogosus, ii. 374 Tropidaster, i. 252. Troxites, i. 407. Truncatulina, i. 117. Tubicola (Annelida), i. 309-315. Tubiporide, i. 218. Tubularida, i. 154. Tubulipora, i. 428, 431. Tubuliporide, i. 426, 431. Tubulosa, i. 188; characters and distri- bution “of, ue 204, 205. Tunicata, i. 411, 413. Turbinella, ii. 9. Turbinide, ii. 5, 26. Turbinolia, i. 189. Turbinolide, i. 189, 190, 211. Turbo, ii. 26, 27. Turrilepas, i. 338, 339, 340. Turvrilites, ti. 59, 75, 84, 85. Turritella, ii. 19, 20. Turritellide, ii. 5, 19. Tylodon, ii. 396. Tylopoda, ii. 355. Tylosaurus, ii. 207. Typhis, ii. 9. Typotheriun, ii. 406. VUintacrinus, i. 284. Uintatherium, ii. 373. Uintornis, ii. 265. Ulimania, ii. 437, 463. Umbrella, ii. 37. Unceites, 1. 446, 447. Unconformability of strata, i. 63-65. Undina, ii. 140. Ungulata, ii. 318, 319. Unio, i. 491. Unionide, i. 468, 491. Uraster, i. 245, 247, 251, 252. Urastereila, i. 249, 251. Urocordylus, ii. 181, 185. Urodela, characters of, ii. 174; distri- bution of, in time, ii. 175. Uronemus, ii. 142. Ursida, ii. 392, 393. Ursitaxus, ii. 395. Ursus, ii. 394. Urus, ii. 368. Uvellidea, i. 106. Vaginulina, i. 109, 114. Valenciennesia, ii. 45. Valvata, ii. 6, 25. Valvular pyramid, of Cystideans, i. 288. Valvulina, i. 100, 112. Vanessa, i. 408. Ve anuxemia, i. 488. Vegetable kingdom, divisions of, ii. 429. INDEX. Del Veneridee, i. 469, 470, 508. Venerupis, i. 504. Ventriculites, i. 146. Ventriculitidee, i. 146. Venus, i. 504. Vermetus, i. 810; ii. 3, 19, 20. Vermilia, i. 315. Verruca, i, 337. Verrucide, i. 335, 337. Verrucocelia, i. 145, 146. Verruculina, i. 149. Vertebruta, characters of, ii. 100-106; distribution of, in time, ii. 107. Vespertilio, ii. 415. Vespertilionidee, ii. 412. Vincularia, i. 428, 430. Vinculariade, i. 430. Vioa, i. 134. Viperine Snakes, ii. 199. Virgularia, i. 219. Viverravus, ii, 396. Vwwerride, ii. 396. Voltzia, ii. 438, 466. Voluta, ii. 13, 14. Volutide, ii. 5, 13. Volutilithes, ii. 14. Volvaria, ii. 14. Vulpavus, ii. 398. Vulpes, ii. 398. Vulsella, i. 477, 479, 480. Walchia, ii. 463, 464. Waldheimia, i. 439, 448. Wardichthys, ii. 139. Websteria, i. 219. Wellingtonia, ii. 473, 474. Whalebone Whales, ii. 313. 4 Willemoésia, i. 392. Williamsonia, ii, 467. Xanthidia, ii. 431. AXantholites, i. 394. Xanthopsis, i. 394. Xenoneura, i. 405. Xenurus, ii. 307. Xiphodon, ti. 349, 350, 352, 358, 360. NXiphodontide, ii, 350, 352. Niphosura, characters of, i. 384; distri- bution of, in time, i. 385. NXiphoteuthis, ii. 95. NXylobius, i. 403. Xylophaga, i. 511. AX ylophayella, i. 511. Yoldia, i. 489, 490. Zamia, ii. 465. Zamites, ii. 466, 467, 474. Zaphrentine, i. 212, 2138. Zaphrentis, i. 208, 209, 212, 213. Zeacrinus, i. 273, 274. Zethide, i. 379. Zethus, i. 379. Zeuglodon, ii. 315, 316. Zeuglodontide, ii. 3138, 315. Ziphioid Whales, ii. 315, Ziphius, ii. 315. Zoantharia, i, 153; Malacodermata, i. 176, 177; Sclerobasica, i. 176, 178; Sclerodermata, i. 176, 179. Zonites, ii. 7, 42, 43 Zoocapst, i, 337. Zygomaturus, ii. 296, Zygosaurus, ii. 182, 184. THE END. Sains « te e ae 7 * oy a wen’ ~y Aan perive? PRINTED BY WILLIAM BLACKWOOD AND SONS. 77 i TT yy dente! Pete See aioe Pie od