166 REPTILES. 



* Anterior and posterior lobes of plastron nearly equal, both freely 

 movable and capable of closing the shell; posterior lobe 

 emarginate behind, its angles rounded; carapace without" 

 traces of keel in adult CINOSTERNUM, 1. 



** Posterior lobe of plastron narrower and longer, truncate behind, 

 its angles rather pointed; lobes of plastron little movable, 

 incapable of closing the shell ; carapace more or less cariu- 

 ated, at least when young; head very large, with strong jaws. 



AROMOCIIELYS, 2. 



/. CINOSTERNUM,^ T &g\QY. SMALL Box TURTLES. 



> Thrynosternum^ Ag. 



1. C. pennsylvanicum, (Bosc.) Bell. SMALL MUD 

 TURTLE. Shell dusky brown; head and neck with light 

 stripes and yellow dots; anterior dorsal plate nearly as 

 broad in front as long; L. 4. N. Y. to Fla. and W. 



2. AROMOCHELYS, Gray. MUSK TURTLES. 



= Ozothecci) Agassi z. 



1. A. odoratus, (Latreille) Gray. MUSK TURTLE. 

 STINK- POT. Shell dusky, clouded, sometimes spotted; 

 head very large with strong jaws; carapace with traces 

 of a keel, but the plates not imbricated in the adult; 

 anterior dorsal plate nearly twice as wide as long in 

 front; a yellow stripe from snout, above eye, down the 

 side of neck and another below eye; a strong musky odor; 

 L. 6. E. U. S., abundant. W. to Indiana. (Levette.) 



2. A. carinaius, Gray. LITTLE MUSK TURTLE. Plates 

 of carapace overlapping more or less, each one edged 

 with black and marked with radiating stripes; neck 

 unstriped. Lower Mississippi region. ( Goniochelys 

 minor ) Ag.) 



FAMILY LXIX. CHELYDRID^E. 



(The Snapping Turtles) 

 Shell high in front, low behind; bulk of body thrown 



