7 6 



TORTOISES AND TURTLES. 



beak is much hooked; and an examination of the skeleton will show that the 

 temporal fossae of the skull differ from those of all the members of the preceding 

 family in being roofed over with bone, as in the following family of the snappers. 

 Moreover, the tail resembles that of the latter in its great length, and also in the 

 circumstance that the articular surfaces of most of its vertebrae have the cup 

 behind and the ball in front, whereas in the tortoise family just the reverse of 

 this arrangement occurs. On the other hand, the carapace resembles that of the 

 latter, and differs from that of the snappers in the absence of a rib-like process 

 from its posterior angles passing backwards beneath the marginal bones. The 



THE BIG-HEADED TORTOISE {\ nat. size). 



carapace is characterised by its extreme depression and oval form; while the 

 plastron is of moderate size, and connected with the carapace solely by ligament, 

 so that bony buttresses are totally lacking. The head is covered with a continuous 

 horny shield, and the hooked jaws are of great power. The toes are of moderate 

 length, and but slightly webbed ; all, save the fifth in the hind-foot, being furnished 

 with claws. The long and cylindrical tail becomes compressed at the end, and is 

 covered with rings of quadrangular shields. In size this tortoise is small, the 

 length of the carapace being only about 6 inches, and that of the tail some three- 

 quarters of an inch more. In the adult the colour is olive-brown above, and 

 yellowish brown beneath, but the young is more brilliantly coloured. Of the habits 

 and mode of life of this tortoise, nothing appears hitherto to have been ascertained. 



