64 REPTILES. 



Fam. II. Alligators, (Alligatoridje). 



Canine teeth of the lower jaw fitting into a pit in the edge of 

 the upper jaw. New World. 



Synopsis of the Genera. 



1. Jacare. Jaws oblong, depressed, with a ridge across the 

 face between the eyes. Hind feet scarcely webbed. Nostrils with 

 a cartilaginous septum. Eyelids fleshy. 



2. Alligator. Jaws oblong, depressed, with a small longi- 

 tudinal rib between the orbits. Hind feet webbed. Nostrils se- 

 parated by a bony septum. 



3. Caiman. Jaws oblong, depressed. Hind feet scarcely web- 

 bed. Nostrils a cartilaginous septum. Eyelids with 3 bony plates. 



1. Jacare. 



Head oblong, depressed, with a ridge across the face before the 

 eyes, rounded in front. Teeth unequal, canines of lower jaw each 

 fitting into a pit in the upper jaw. Toes scarcely webbed. Nu- 

 chal and cervical plates united into one group. Eyelids fleshy, 

 only partially bony. Nostrils only separated by a cartilage. 



* Preorbital ridge to the edge of the jaw. Maxillary pits 3-3. 

 Frontal ridge bent backward. 



The Broad-headed Yacare. Jacare fissipes. Caiman fissi- 

 pes, Spix, Braz. t. 3. Wagler, Icon. t. 17. Natterer, Ann. Mus. 



Vien. 321, t. 22. A. sclerops, Nieuweid, Abbild. t. Schinz. 



Rept. t. 12. A. cynocephalus, Dum. et Bib. E. G. iii. 86. C. la- 

 tirostris, Daud. 



Head short, ovate, triangular; muzzle short, broad, thick, fron- 

 tal ridge sinuate, preorbital ridge longitudinal, to the edge of the 

 jaw ; maxillary pits 3-3 ; upper part of the eyelid rugose ; nape 

 with 2 rows of shields ; nuchal shields many, 3-rowed ; cervical 8, 

 in 3 rows ; scales of the back square, rather sharply keeled, 4 on 

 each of the three last cross bands ; sides with some scattered lar- 

 ger keeled scales ; back greenish, black-spotted. 



a. Very young, in spirits. Trop. America. 



J, e,f. Young, stuffed. Length 23 — 32 inches. 



c. Nearly adult, stuffed. Length 59 inches. Brazils. 



d. Adult, stuffed. Length 72 inches. Brazils. 



The Yacare. Jacare sclerops. Crocodilus sclerops, Schn. 

 Amph. 162. Cuv. Ann. Mus. x. <f Oss. Fos. v. t. 1,/. 6, 7, t. 2,/. 

 3. Tiedem. Amph.60,t. o. Guerin, Icon. t. 2,/. 2, Sr 20. Gray, 



