upper shell is smooth, flattened, unindented at the edges, oval in 

 outline, and widest behind the middle. 



The lower shell is large in proportion, has no hinge, and is fasten- 

 ed rigidly to the upper shell. Its scales are all black if the turtle is 

 very young, but increasingly light yellow toward the middle in an 

 older animal. The shell of the male is concave, that of the female 

 somewhat convex or else flat, and more nearly reaching to the pos- 

 terior edge of the upper shell than in the male. 



There are certain difi^erences between the heads of the two sexes. 

 The head of the male is larger and is black, including the bony por- 

 tion of the jaws. Usually there is no yellow stripe on the lower jaw. 

 The eyes are dark brown, and the black throat is finelv speckled 

 with orange. The head of the female is somewhat smaller, and the 

 horny portion of the jaws is light yellow. In addition, there is a 

 bright yellow stripe along the lower jaw. The eyes are bright 

 orange, and the throat is streaked and spotted with yellow. 



Size. Maximum length of upper shell about 1 1 5 mm., width 

 86 mm. 



[91] 



