FOSSIL REPTILES. 205 



the head, in the crocodiles properly so called, and their com- 

 parison with those of the mammifera. 



One advantage in studying the osteology of the crocodile, 

 and indeed that of many other reptiles, is, that the sutures do 

 not become effaced. It is not so easy, however, to refer each 

 bone to its analogous one in man and other animals, as to reckon 

 them, and on this subject anatomists have differed much. 



The muzzle of the crocodile is elongated and depressed. The 

 external aperture of the nostrils, placed near its anterior ex- 

 tremity, is directed upwards, pretty nearly as it is in the La- 

 mantin. There is but a single incisive foramen, because the 

 intermaxillaries have no middle apophysis, which is likewise 

 the case in the animal just mentioned. The intermaxillaries 

 surround the external nostrils, excepting one place, very 

 narrow where the point of the nasal bones is placed between 

 them. This is the case, more or less, with the majority of 

 mammalia. 



On each side the maxillary supports thejugal behind, which 

 goes to form the external edge of the orbit. This edge would 

 be the lower one in most animals, but here it is external, 

 in consequence of the opening of the orbit being directed 

 towards the top. 



Underneath, the palatine bones prolong the roof, furnished to 

 the mouth by the intermaxillaries, and by the maxillaries ; but 

 while they prolong it they also render it more narrow, because 

 they leave a void between themselves and the elongations of 

 the maxillaries, which support the jugals, and which void serves 

 for the passage of the crotaphite muscles. 



The lachrymal bone occupies on the cheek an oblong 

 space, between the nasal, the maxillary, and the jugal. It re- 

 enters the orbit by a sort of plane contiguous to the jugal and 

 to the maxillary, in which plane is pierced the lachrymal canal : 

 all this is exactly an arrangement similar to that in the mam- 

 mifera ; but we must now observe the differences. 



In the mammalia, the frontal bone would commence imme- 



