166 EEPTILES. 



* Anterior anCl posterior ^dhes of plastron nearly equal, both freely 

 movable and capable of closing tbe shell; posterior lobe 

 emai'ginate behind, its angles rotmded; cai'apace without 

 traces of keel in adult CrtfOSTBRNtrM, 1. 



** Posterior lobe of plasti-on 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. 



Aromoohblts, 3. 



/. C/NOSTERIVUM,Wa.g\eT. Small Box Turtles. 

 ' > Thri/nosternum, 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. AROMOCHEirS, Grsiy. Musk Turtles. 

 = Oeotheca, Agassiz. 



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. 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. {Qoniochelys 

 minor, Ag.) 



FAMILY LXIX. — CHELYDRIDiE. 



{The Sncvpping Turtles) 

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



