250 Trans. Acad. Sci. of St. Louis. 



is deepest forward and bluntly toothed posteriorly. Lower jaw also 

 with a sharp edge and both jaws furnished with an alveolar surface, 

 the leathery snout ending obliquely, so that the nostrils are somewhat 

 under the tip. The nostrils are circular, there being no papilla pro- 

 jecting Into them from the septum. 



Body is oval and flat. No trace of a keel along the middle of the 

 back; often a depression instead. No spines along the anterior border 

 of the carapace, nor any tubercles anywhere. Callosities well developed 

 on the plastron of the adults, especially of the males. (Hay.) 



Color. — ^Adults brown above, whitish below. Back irregularly blotched 

 with darker brown. Head with a white stripe, margined with black 

 from the eye over the ear and descending on the neck, head and neck 

 below the level of the edge of upper lip white, without mottling. Under 

 side of the feet white or bluish-gray, never mottled, a yellowish border 

 around the edge of the carapace. In the young the lateral and poste- 

 rior margin of the carapace is banded with yellow, bordered internally 

 with black, and inside of that sprinkled with small brownish dots. 



Size. — Length of carapace 356 mm.; width of same 305 mm.; depth 

 55 mm. Length of plastron 254 mm. 



Habitat. — Central and northern tributaries of the Mis- 

 sissippi Eiver and tributaries of the St. Lawrence. Mis- 

 souri localities : — Mississippi, Osage, Gasconade, and Mer- 

 amec Eivers. 



Habits. — Ditmars in his Reptile Book gives the follow- 

 ing life history of this turtle: — ^^Old logs, protruding a 

 moist and slimy surface a few inches from the water, 

 sometimes tempt these creatures from the element for 

 which they are specially provided. In such situations they 

 lie taking a sun-bath, with limbs withdrawn beneath their 

 flabby ^^ shells^' and their long necks stretched to the full- 

 est extent, imparting the idea of as many snakes, emerg- 

 ing from under flat stones. At the least alarm they 

 scramble frantically for the water, but upon reaching it 

 their clumsy movements are instantly transformed. 

 Against the resisting surface, the broad, fin-like feet take 

 great purchase and the frightened reptiles disappear with 

 almost the agility of a scurrying school of fishes.'' 



*^The soft-shelled turtle at bay is one of the most vicious 

 of cold-blooded creatures. Moreover, the knife-like edges 

 of the jaws of large individuals are formidable weapons, 



