TURTLES AND TORTOISES 11 



species the writer has failed to secure a picture unless 

 confronted by a pair of widely-gaping jaws. On one 

 occasion, a leg of the tripod was bitten off clean and 

 always were the diminutive but bright, sunken eyes 

 watching the movements of the writer's feet with an 

 intensity of purpose that inspired caution. 



The dull, yellow shells of these big turtles exactly 

 match the coffee-colored waters of the lower Mississippi, 

 where they are common. Lying motionless upon the 

 oozy bottom they are approached by unwary fishes, when 

 a dart of the head procures the prey. Captive speci- 

 mens do not feed well unless provided with means of 

 hiding; from such the head is frequently protruded, 

 when the tip of the conical snout barely touches the sur- 

 face of the water in a search for air. If a large fish — • 

 like a shad — is thrown into the tank, it is devoured by 

 a series of clean-cut bites that match the conformation 

 of the turtle's jaws. 



Family Dermatemydidce: The fresh-water turtles 

 composing this small family are restricted to southern 

 Mexico and Central America. Their structure shows 

 them to be intermediate between the Chelydridce and the 

 Cinosternidce. They are characterized by their very 

 short tails. Dennatemys has a wide plastron connected 

 with the upper shell by a broad bridge. The single 

 species, D. mawii, has a shell about a foot long, when 

 adult; it is olive above and yellowish beneath; the sides 

 of the head are speckled. Staurotypus has the carapace 

 much flattened, with three, faint keels; the plastron is 

 narrow and cross-shaped like that of the snapping tur- 

 tles, while the front lobe is hinged. Shells of adult 

 specimens are about a foot long. Claudius differs from 

 the preceding genus in having the front lobe of the 

 plastron rigidly attached. 



