154 DR. J. E. GRAYS SYNOPSIS OF THE SPECIES 
1. ToMISTOMA SCHLEGELI. (Bornean Gavial.) 
‘rocodilus gavialis schlegelii, Miller, Naturgesch. Ost. Ind. t. 123. f. 1-5. 
Crocodilus schlegelii, Blainv. Ostéog. Crocod. t. 2. f.3; t.5.f.4. Brihl, Skelet. Krok. t. 8. f. 6. 
Owen, Fossils of the London Clay, p. 15. 
Rhynchosuchus schlegelii, Huxley, Proc. Linn. Soe. iv. (1859) p. 17; Ann. & Mag. Nat. Hist. 1859. 
Mecistops journei, Gray, Cat. Tortoises &c. B. M. 38, not synonyma. 
Hab. Australasia, Borneo (Miller, Brit. Mus.). 
The two figures of the skull in Miller and Schlegel, t. 3. f. 1 and 2, show the difference 
that occurs in the form of the skull of the same species. 
In the British Museum there is a young specimen in spirits, and an adult skull 
received from the Leyden Collection, and a very fine adult skull from Borneo, obtained 
from Mr. Mitten. 
Family Il. CROCODILIDZ. 
The cervical plates forming a distinct shield, separate from the dorsal shield. Teeth 
strong, very unequal in size, hinder larger. The 9th upper and the 11th lower teeth 
larger, like canines, the large teeth of the lower fitting into pits or perforations, and 
the canines fitting into notches on the edge of the upper jaws. Nose of both sexes 
simple. 
The upperside of the intermaxillary is slightly expanded behind, and its hinder end 
is divided, and separated into two parts by the front end of the nasal bone. 
Crocodilide §**, Gray, Cat. Tortoises &c. B. M. 36, 1844. 
Crocodilide, Huxley, Proc. Linn. Soc, Zool. iv. 5. 
Crocodilus, Cuvier ; Gray, Ann. Phil. 1825, x. 195. 
Champse, Merrem, Tent. 
Professor Huxley divides this family into two genera, Crocodilus and Mecistops. See 
Journ. Proc. Linn. Soc. Zool. iv. 6. 
The Crocodiles when they are first hatched have a very short beak to the head. This 
is even the case with the long-beaked Mecistops cataphractus, which in its very young 
state is hardly to be distinguished in the form of its beak from the young of the com- 
mon Crocodile, Crocodilus vulgaris. 
As the young obtain strength the beak developes itself more or less rapidly according 
to the species, until its normal character is attained. 
The head seems to continue of nearly the same form, merely increasing in size, for 
some time, perhaps years ; for we know little of the duration of the life of the Crocodiles ; 
and they are probably long-lived animals. As they reach maturity, and as old age creeps 
on, the skull thickens considerably, and the jaws dilate and thicken on the sides. The 
growth of the teeth, which are produced in succession, and greatly enlarge in diameter, 
and the enlargement of the jaws proceed pari passu: the latter is also influenced by the 
development of these teeth and the larger alveoli required to support them. 
