CROCODILIA. 29 



molars in Mammalia. It follows, therefore, that the number of the teeth of the cro- 

 codile is as great when it first sees the light as when it has acquired its full size ; and, 

 owing to the rapidity of the succession, the cavity at the base of the fully-formed 

 tooth is never consolidated. 



The fossil jaws of the extinct Crocodilians demonstrate that the same law regulated 

 the succession of the teeth at the ancient epochs when those highly organized reptiles 

 prevailed in greatest numbers, and under the most varied generic and specific modi- 

 fications, as at the present period, when they are reduced to a single family, composed 

 of so few and slightly varied species, as to have constituted in the Systema Naturte of 

 Linnaeus, a small fraction of the genus Lacerta. 



Crocodilus toltapicus, Owen. Tab. II, fig. 1, and Tab. II A. 



Syn. Crocodile de Sheppy (?), Cuvier. Ossemens Fossiles, 4to, torn, v, pt. ii, p. 165. 



Crocodilus Spenceri, Buckland. Bridgewater Treatise, vol. i, p. 251. "Crocodile 

 with a short and broad snout." Vol. ii, p. 36, pi. 25', fig. 1. 

 — Owen. Reports of the British Association, 1841, p. 65. 



In proceeding to the comparison, and preparing for the description of the British 

 fossil Crocodilia, I endeavoured, in the first place, to obtain the bones of the species 

 which now exists in a locality nearest to Great Britain, and also of an individual of that 

 same species which had lived at a remote period ; and I have been favoured by the 

 kindness of my esteemed friend Philip Duncan, Esq., Fellow of New College, Oxford, and 

 Conservator of the Ashmolean Museum, with the opportunity of examining the bones of a 

 mummified Crocodile from a sarcophagus at Thebes, in that collection at Oxford. Two 

 views of the skull of this old Egyptian Crocodile are given in T. I. The total length 

 of the skull from the bone marked 28 to the end of 22, is twice the breadth of the back 

 part of the skull. The upper apertures of the temporal fossae are subcircular ; the point of 

 the squamosal (27) projects into the lateral aperture. The breadth of the back part of the 

 sculptured cranial platform (8, s), is less by one fourth than the breadth of the skull anterior 

 to the orbits. The breadth of the interorbital space is nearly equal to the transverse 

 diameter of the orbit. The points of the nasals (15) project into the external nostril. 

 The postpalatal apertures reach as far forwards as the seventh tooth, counting from 

 the hindmost; there are nineteen alveoli on each side of the upper jaw, the five 

 anterior teeth being lodged in the premaxillary, which is perforated by the first tooth 

 of the lower jaw. 



Geoffroy St. Hilaire has applied the old Egyptian name 1.ovyog to the mummified 

 Crocodiles of that country ; but there is no good specific character which distinguishes 

 them from the modern Crocodiles of the Nile, to which Cuvier has given the name of 

 Crocodilus vulgaris. 



Cuvier appears to have first called the attention of palaeontologists to the remains 



