CHAPTER VllI: THE SOFT-SHELLED TURTLES 



Genus Trionyx 



Strongly Characteristic Chelonians, with a Soft, Leathery Shell 



Classification. — The family Trionychidce is composed of 

 about twenty-seven species embraced witliin six genera. A 

 few species inhabit North America; the majority occur in south- 

 ern Asia and the East Indies; several species inhabit Africa. 

 The largest genus is Trionyx. Ail of the North American species 

 belong to this genus; the other species inhabit both Asia and 

 Africa. 



Structure.- — From all of the other chelonians the Soft-shelled 

 Turtles are strikingly distinct. The shell is exceedingly flat 

 and in its outline is either bluntly oval or almost circular. Lack- 

 ing the hard shields of other turtles, the carapace and the plas- 

 tron are soft and leathery: the former bends freely at the edges, 

 and droops, like a flap, over the orifice through which the head 

 and neck are withdrawn in time of danger. 



The neck of the Soft-shelled Turtle is very long, the head 

 is narrow and the snout is provided with a slender proboscis, at 

 once imparting a characteristic aspect. While the general 

 appearance of these creatures is fleshy and inoffensive, and the 

 jaws are provided with lip-like folds of skin, the latter cover 

 powerful and keen-edged mandibles and these reptiles bite 

 with the energy of the snapping turtles. The head and neck 

 are completely retractile. As the species are very aquatic, 

 the feet are broad and extensively webbed. 



General Habits. — All of the Soft-shelled Turtles inhabit 

 rivers, ponds and lakes with a soft, muddy bottom. They 

 seldom or never leave the water unless to deposit their eggs — 

 a short distance above the waterside. These reptiles frequently 

 take the hooks of fishermen. They are uniformly agile and 

 vicious; large individuals are dangerous. 



In the areas inhabited by these turtles in the United 

 States, they are commonly called the " flap-jack_ tur- 



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