166 KEPTILES. 



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

 movable and capable of closing the shell ; posterior lobe 

 emarginate beliiml, its angles roimded; 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 carin- 

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



Akomociielys, 2. 



/. C//\/0STER/\fUM,W8ig\er. Small Box Turtles. 



> Thrynosternum^ Ag. 



1. 0. 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. JIROMOCHELYS,Gmj. Musk Turtles. 

 = Ozotkeca^ Agassi z. 



1. A. odorafus, (Latreille) Gray. Musk Turtle. 

 Stink -Pot. Shell dusky, clouded, sometimes spotted; 

 head very large with strong jaw^s; carapace with traces 

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

 anterior dorsal plate nearly tw^ice as wdde 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. carinatus, 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. — CHELYDRIDJ^. 



{The Sncipping Tnrtles) 

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



