cheons, variously arranged, and which are the supports of the dermal scales and spines.

In the gigantic Gavial that inhabits the Ganges, and other rivers of India, and which is remarkably distinguished by its extremely slender, prolonged, beak-like muzzle, the nape of the neck is protected by a complete shield, formed of sixteen or eighteen transverse rows of dermal plates, of which there are also six longitudinal series that extend down the back.

These scutes are deeply corrugated externally, a structure adapted for the firm adhesion of the scaly integument; the largest in Dr. Grant's Gavial are 4 by 3 inches in dimension.

In the Swanage Crocodile the external surface of the dermal plates (Lign. 40, fig. 1), is covered by numerous, irregularly

LIGN. 40.-DERMAL BONE OF THE SWANAGE CROCODILE. (nat. size.) 1. The external surface.

2. The inner surface.

a. The lateral connecting process.

round and angular pits, or depressions, while the inner surface (fig. 2) is smooth and glossy, and finely striated by decussating lines, as in the dermal process of the Hylæosaurus.

These scutes differ from those of all known recent and fossil crocodilians in possessing a lateral conical projection (a, Lign. 40), which fits into a depression on the under surface of the opposite angle of the adjoining plate, resembling, in

this respect, the scales of the large Wealden fish, the Lepidotus, with which the remains of Goniopholis are frequently associated.

Numerous hexagonal and pentagonal scutes, united by marginal sutures, also entered into the composition of the dermal cuirass of this reptile, which must, therefore, have possessed a flexible and impenetrable coat of armour, capable of affording protection against the attack of any assailant.

From the structure of the skeleton of the Goniopholis, we may infer that the original was a powerful carnivorous reptile, resembling in its habits the existing Crocodiles and Gavials, and frequenting the rivers and marshes of the country inhabited by the colossal terrestrial lizards with whose remains its bones and teeth are generally found associated throughout the Wealden deposits of England and Germany.

FOSSIL CROCODILIANS.-As the cabinet under review contains the remains of several other species and genera of crocodilian reptiles, it will be convenient to notice them under this section, and afterwards examine the Batrachians, Pterosaurians, &c. that are placed next in order to the Swanage Crocodile above described.

The loricated, or mailed saurians, the Alligators, Crocodiles, and Gavials, are the largest living forms of cold-blooded oviparous quadrupeds. No relics of any recent species of these genera have been observed in a fossil state; but remains of Crocodilians of the existing generic types, having the spinal column composed of concavo-convex vertebræ, have been found in the Isle of Sheppey, on the coasts of Western Sussex and Hampshire, and other localities of the London clay.

It may be stated in general terms, that of the Crocodilians with broad muzzles, as the Cayman, and Alligator, no representatives have been found in formations more ancient than the Tertiary; those of the Secondary deposits being all referable to the division with elongated beaks, like the Gavials, which are characterised by their long and extremely narrow jaws, with teeth that are nearly of equal size, and alike in form; their feet are palmated. They inhabit the Ganges and other rivers of India, and sometimes attain a length of thirty feet. The fossil Crocodilians of the Gavial type are subdivided into two groups; the Teleosaurus, in which the nasal

apertures terminate in two distinct orifices, instead of being blended into a single opening as in the recent Gavials; and the Steneosaurus, in which the breathing canals end in two nearly semicircular vertical orifices at the extremity of the muzzle.1

Geosaurus (G. Sommeringii). Wall-case A-B. (See ante, p. 153.) The remains of a small crocodilian reptile, consisting of a considerable portion of the vertebral column with the ribs, and the anterior part of the skull with the jaws and teeth, are deposited on the lowermost ledge in the angle between the Wall-cases A and B. These fossils are mentioned in the official "Synopsis of the British Museum," as the head and other parts of the Geosaurus, (Lacerta gigantea, of Sommering,) found in the white Lias, at Monheim, in Franconia; being the original specimens figured and described by Sommering, in the Transactions of the Academy of Munich. They are also figured and described by M. Cuvier, ("Oss. Foss." tome v. p. 338, Pl. XXI. figs. 2—8.)

The vertebral column, in two portions, partially imbedded in fissile marlstone, is placed in the long cases in the centre; and the two parts of the cranium and jaws are in the small cases on the right hand.

The teeth of this extinct crocodilian reptile are flat, pointed, and recurved backwards like a sabre, the edges being finely serrated; there are seventeen on each side the upper jaw. The eye was very large, and the sclerotic coat protected by a zone of osseous plates, as in the Ichthyosaurus. The vertebræ are biconcave and slightly contracted in the middle; their transverse processes are very large and strong.

From the form and structure of the cranium, M. Cuvier inferred that the original held an intermediate place between the crocodiles and monitors, but was most nearly allied to the latter. The length of the reptile was probably nine or ten feet.

Macrospondylus. Wall-case B. Uppermost Shelf. The

1 "In the Teleosaurus the nostrils form almost a vertical section of the anterior extremity of the beak; in the Steneosaurus this anterior termination of the nasal canal had nearly the same arrangement as in the Gavial, opening upwards, and being almost semicircular on each side." -Dr.Buckland's "Bridgewater Essay," p. 252, Pl. XXV.

fossil thus labelled consists of the cranium and part of the vertebral column, with many ribs, of a small saurian reptile, from the Lias at Boll, which has been referred to a distinct genus by H. von Meyer. I have not been able to obtain any further information respecting this specimen.

Crocodilus toliapicus. Wall-Case B. [2.]-The discovery of the cranium of this species in the London clay of the Isle of Sheppey described by Baron Cuvier, afforded the first certain proof of the existence of a true crocodile in the eocene deposits of England. The specimen in the Case before us is remarkably fine it is above two feet long, and both jaws and teeth are in a beautiful state of preservation. The recent Crocodilus acutus of the West Indies is stated to be the nearest living representative of this ancient tertiary species.

Crocodilus Spenceri. Wall-Case B. — A remarkably fine skull of a crocodile, two feet in length, and ten inches in width, from the Isle of Sheppey, is placed on the ledge near the specimen last described; a cranium of this species is figured in Dr. Buckland's "Bridgewater Essay," Pl. XXV. ; and described in "Brit. Assoc. Report," p. 65.

Professor Owen states that the most characteristic differences which this species presents in comparison with the Crocodilus biporcatus, or other existing species of Crocodile or Alligator, are the larger size of the temporal holes, as compared with the orbits, the more regular and rapid diminution of the head towards the snout, the straight line of the alveolar tract, and the greater relative length and slenderness of the muzzle. It most nearly resembles the Bornean species (Croc. Schlegelii.)1

Remains of this Crocodilian reptile have been obtained from the London clay at Bracklesham, on the Sussex coast t; and I have collected several vertebræ, dermal bones, teeth, and portions of the cranium, from the eocene strata near Lymington.2

In Mr. Dixon's collection there was a chain of eight vertebræ, including the sacral and biconvex first caudal, which is

1 For details consult "Brit. Assoc. Report," (1841), pp. 66, 67. 2" Geological Excursions round the Isle of Wight, and along the aljacent coast of Hampshire," p. 163.

figured in Pl. XV. of his beautiful work on the fossils of some of the cretaceous and tertiary deposits of Sussex.

TELEOSAURUS. To this genus belong several interesting fossils contained in the Wall-case B.-In reference to the general characters of the extinct Crocodiles comprised in this group, the eminent palæontologist Herm. von Meyer observes that "the form of the head approaches that of the Gavials, but the beak or mandible is longer and more slender, and the teeth more numerous: the first tooth is generally very long, and the other teeth are alternately longer and shorter. The head is from three to four feet in length. The hinder articular surface of the bodies of the vertebræ is concave; and their processes show considerable departure from those of Crocodiles. The skin was covered by broader and thicker scales than in the Crocodilians, and these scutes overlaid each other in such manner as to constitute a strong flexible coat of mail. The scales are deeply pitted externally by hemispherical depressions; and their form, structure, and arrangement, led M. Geoffroy to conclude that the living Teleosauri must have been more decidedly aquatic than the Crocodiles, and were probably marine animals.

In their general shape the Teleosauri are more slender than the Gavials, and the feet are better adapted for swimming than for walking; the fore-feet being not more than half the size of the hinder ones. This disproportion of the organs of progression, together with the scaly dermal integument, must have rendered the motions of these animals difficult on land, but in the water they could move with great facility, and there can be little doubt that these ancient gavial-like saurians inhabited the seas of the Secondary Epochs.'

Teleosaurus.-Wall-case B.-A cranium with the jaws and teeth most beautifully preserved, the extremity of the muzzle being entire, and exhibiting the apertures of the nostrils, is placed in the recess near the Crocodilus toliapicus; but I have not been able to obtain any information respecting this fine specimen. On the same ledge is the upper part of the cranium of another example of Crocodilus Spenceri.

1 From "Palæologica zur Geschichte der Erde und ihrer Geschöpfe, von Hermann von Meyer." Frankfort, 1832.

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