III. Order EMYDOSAURIA. 



Quadrate bone united to the skull, not movable; temporal 

 region with two horizontal bony arches. Teeth present, im- 

 planted in alveoli of the jaws. Cervical and dorsal ribs mostly 

 two-headed; sternum and interclavicle present; seven or eight 

 transverse series of abdominal ribs, free from the vertebral ribs. 

 Anal opening longitudinal; copulatory organ present, single. 



A single family, with a wide distribution, occurring in tropical 

 America, Africa, S. Asia, N. Australia. 



i. Fam. CROCODILIDAE. 



Nostrils anterior; pupil vertical; ear with movable opercles; 

 choanae far back between the pterygoids, which form a median 

 suture like the palatines and maxillaries; orbit communicating 

 with the infratemporal fossa. Back armed with bony plates. 

 Fore limb with five digits, hind limb with four; the three 

 inner digits clawed. Tail strong. 



Carnivorous, aquatic reptiles, laying elongate eggs (fig. 130, 

 132) with a hard shell on the banks of the rivers in a hollow, 

 covered up with sand. Two genera of six recent ones are 

 represented in the Indo-Australian region. 



A. Snout long and very narrow; - teeth on 



each side I. Tomistoma, p. 333. 



/>. Snout broad, tapering; teeth on each side. . 2. Crocodilus, p. 336. 



i. Tomistoma S. Muller. 



(S. MULLER, Arch. F. Nat. p. 122, 1846). 



Snout very long and narrow; 20 or 21 upper and 18 or 19 

 lower teeth on each side, the lateral mandibular received into 

 pits; fifth maxillary tooth largest; first and fourth mandibular 

 teeth fitting into notches of the upper jaw. Nasal bones not 

 extending to the nasal opening, in contact with the prae- 



