Liberia <»' 



sub-order, is also a visitor to the Liberian sea-coast. Its 

 leathery carapace rises into strongly marked ridges along the 

 back and sides that are composed of small discs of bone, almost 

 fused together, and covered with a leathery skin. This, together 

 with the plastron or belly-shield (equally studded with ridges 

 of bony nodules) is quite distinct from the bones of the vertebras 

 and the ribs, and in this particular therefore the leathery turtle 

 differs from all the rest of the order. Its habits are entirely 

 marine. The flippers are exceedingly long. 



In the marshes and rivers of Liberia fresh-water tortoises 

 are found of the genus Sternothicrus. They may be distinguished 

 from other groups by the sideways flexion of the neck when 

 it is withdrawn under the shell. Other members of the order 

 outside the side-necked families withdraw their necks under 

 the carapace in perpendicular loops, or backwards into a sheath. 

 The Sternotheres and their allies in Africa and America curve 

 their long necks round to one side between carapace and 

 plastron. Sternothcerus frequents fresh water, and is carnivorous. 

 The shell is bony, and the size of the animal is not large — 

 perhaps a foot long. The Trionychida or Soft tortoises, on the 

 other hand, retract their necks into a sheath of loose skin. 

 Their nostrils are prolonged into a short proboscis. The 

 carapace is covered with a smooth, leathery skin with a crenellated 

 edge. They can therefore at once ha distinguished from land 

 and water tortoises by the absence of the segments between the 

 plates of the carapace. They do not grow to any great size, 

 are almost wholly aquatic, very carnivorous and ferocious, and 

 bite sharply with the bony rims of their jaws. 



The true Tortoises are represented by the genus Cinyxis. 

 In these forms the back part of the carapace over the loins is 

 hinged, so that it can be moved independently of the front 

 portion of the carapace. When these Cinyxis tortoises have 



820 



