76 
TORTOISES AND TURTLES. 
beak is much hooked; and an examination of the skeleton will show that the 
temporal fossse 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 vertebras 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 (i Hat. 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 liind-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. 
