ORDER CROCODILIA. 



1195 



moderately elongated, with its dental borders thrown into distinct 

 festoons (fig. 1092) ; by the nasals always reaching the premaxillae, 

 and frequently extending down to the anterior nares (as in fig. 1092) ; 

 and also by the orbits being always larger than the supratemporal 

 fossae. The short symphysis of the mandible, from which the 

 splenial element is entirely excluded (fig. 1093), is another striking 

 feature. The teeth, moreover, vary in size in different parts of the 

 jaws ; and usually the third and ninth in the upper, and the fourth, 

 and frequently also the first and eleventh, in the lower jaw (fig. 



Fig. 1093. — Inner view of the left ramus of the mandible of a Crocodile. Reduced, an, Angular ; 

 ar, Articular ; co, Coronoid ; d, Dentary ; 5, splenial ; su, Surangular ; sy, Symphysis. 



1093), are considerably larger than any of the rest. In the type 

 genus Crocodilus the upper and lower teeth mutually interlock ; the 

 first lower tooth bites into a perforation or a pit in the cranium, 

 and the fourth into a lateral notch ; while the third lower tooth is 

 small. There is, moreover, no ventral armour. This genus is now 

 distributed over nearly all the warmer regions of the globe, and it 

 appears to have had an equally extensive distribution in Tertiary 

 times. 



The earliest representative of this genus seems to be C. Spe?iceri, of 

 the Lower Eocene of both England and Italy, which was a species with 

 a comparatively long muzzle like that of the living American C. interme- 

 dins. The genus is also represented in the Middle Tertiaries of Europe 

 and North America. In the Pleistocene of Queensland we meet with 

 remains of the existing C. porosns (fig. 1079), which now ranges from 

 Australia to Eastern India ; while in the Pliocene of the Siwalik Hills of 

 India there occur species closely allied to the short-snouted C. palustris 

 (fig. 1092) of that country, which makes the nearest approach in cranial 

 characters to the Alligators and their allies. 



Diplocynodon is an extinct genus found in the Tertiaries of both 

 Europe and North America, which presents characters intermediate 

 between Crocodilus and Alligator. Thus the cranium (fig. 1094) is 

 very short and broad ; the upper teeth bite on the outer side of the 

 lower ; the fourth lower tooth is normally received into a notch 

 (but occasionally into a pit) in the cranium ; the third lower tooth 

 is as large as the fourth ; and there is a complete ventral armour. 

 In Europe this^enus ranges from the Upper Eocene to the Lower 

 Miocene (Upper Oligocene), and is common in the Tertiaries of the 



