56 REPTILES. 



Order IV. EMYDOSAURIANS, (EMYDOSAURI). 



Head large, covered with a thin skin : ears linear, closed with 

 2 valves : gape wide : tongue short : jaws with a single series of 

 conical teeth, inserted in sockets and replaced by teeth formed be- 

 neath them, hinder part of the lower jaw produced behind the con- 

 dyle : nostrils small, anterior : eyes small. Throat with 2 glands. 

 Neck and sides of the body with a wrinkled skin, covered with 

 small tubercular scales. Back with a hard disk, formed of longi- 

 tudinal series of square, keeled, bony plates, imbedded in the skin ; 

 under surface covered with smooth, thin, square plates ; back of 

 the neck with 2 groups of bony plates, the first called the nuchal, 

 and the other the cervical plates. Tail compressed, with 2 series 

 of compressed plates above. Vent longitudinal. Legs short ; feet 

 webbed ; toes 4-5, but only the inner three of each foot clawed. 

 Living in fresh and brackish water in tropical climates. Eating 

 animals which they have killed by drowning. 



Synopsis of the Families. 



1. Crocodilid^. The lower canines fitting into a notch in the 

 edge of the upper jaw. 



2 Alligatoeid^;. The lower canines fitting into a pit in the 

 upper jaw. 



Fam. I. Crocodiles, (Crocodilids:). 



The lower canines fitting into a notch in the edge of the upper 

 jaw. The hind legs with a fringe of compressed scales behind. 



Synopsis of the Genera. 



* Teeth all uniform. Nose of the male very large, inflated. 



1. Gavialis. Jaws very long, slender, subcylindrical. Cervical 

 and dorsal disks united together. 



** The 9th upper and llth lower teeth longer, like canines. Nose 

 of both sexes simple. 



2. Mecistops. Jaws oblong, slender, depressed. Cervical and 

 dorsal disks united. Hind feet webbed. 



3. Crocodilcs. Jaws oblong, depressed. Nuchal, cervical and 



dorsal disks separated from each other by small scales. 



