TURTLES AND TORTOISES 49 



At various times the writer has kept young Hawk's- 

 Bill Turtles in small tanks that have been made brackis 1 

 by adding ordinary salt to the water. His specimens 

 were from six to eight inches long; they were vora- 

 ciously fond of cut-up fish, taking the food from one's 

 ringers. Some of them lived for over a year. In a 

 capacious tank of sea-water, young or adult turtles will 

 thrive indefinitely. 



The Pleurodira: The second superfamily of the 

 Thecophora is characterized by the method of bending 

 the neck when the head is drawn into the shell. The 

 neck bends in lateral curves (sideways). With most 

 of the species the characteristic is externally evident — 

 the side of the head, when that organ is drawn into the 

 protective covering of the shell, being exposed and vis- 

 ible. Members of the Pleurodira have the pelvis fused 

 to the shell. 



Family Pelomedusidce: The neck is completely re- 

 tractile within the protection of the shell, which is cov- 

 ered with horny shields. Most of the species look like 

 big mud turtles (Cinosternidce) owing to their somber, 

 oval shells, the hinged plastron (with some), together 

 with the large head — terminating in a sharp, conical 

 snout. They inhabit muddy rivers of South America, 

 Africa and Madagascar. 



Sternothcerus contains ten species inhabiting tropical 

 and southern portions of Africa — and Madagascar. 

 The plastron is wide, with a hinged front lobe. All of 

 the species are dull brown or black and altogether 

 aquatic. 



Strikingly similar in habits as well as external appear- 

 ance to the American species of Cinosternum is the 

 African Mud Turtle, Sternothcerus derbianus. The 

 young have a strong keel on the upper shell which be- 



