The Musk or Mud Turtles 



The Genus Cinosternum. Six species of Cinosternum occur 

 in the United States and northern Mexico; they may be at once 

 recognised from Aromocbelys by the much broader plastron, 

 the lobes of which can be drawn upward against the lower edge 

 of the carapace, covering the limbs and fleshy parts. While 

 the species of Aromochelys are usually known as Musk Turtles, 

 the reptiles of the present genus are more generally called Mud 

 Turtles, though they exude much the same musky odours as the 

 former. Their habits are quite similar to those of the Musk 

 Turtles 



THE COMMON MUD TURTLE 



Cinosternum pennsylvanicum, (Bosc.) 



The upper shell is broader and more flat than with the 

 musk turtles.* The plastron is nearly as wide as the opening 

 of the shell the front and rear lobes loosely hinged and capable 

 of being drawn upward to protect the head, limbs and fleshy 

 parts. 



Colouration. Upper shell dull olive or brown, the shields 

 with narrow black margins. The plastron is yellow or pale 

 brown. 



With the exception of the jaws, which are of a uniform 

 olive, the head is usually brown, with numerous, greenish-yellow 

 spots. On some specimens these spots run together, forming 

 yellowish stripes on the sides of the head, a condition which 

 causes the head to resemble that of the musk turtle, (A. odoratus), 

 but the broad plastron at once distinguishes this species from 

 the former. 



Dimensions. The Common Mud Turtle attains a maximum 

 size of four inches. Following are the measurements of an av- 

 erage sized specimen: 



Length of Carapace 3^ inches. 



Width " ' r 2* 



Length of Plastron 3^ 



Width of Front Lobe at Hinge i 



" " Rear " " " i* 



Length of Bridge f 



Width of Head f 



* On the carapace of young specimens are three faint keels. On 

 occasional adult specimens there is a blunt, central keel. 



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