REPTILES 



213 



rounded, and the toothless jaws, covered as in birds with firm 

 horny sheaths, give it a very characteristic appearance. Two 

 small rounded nostrils are seen close together on the front of 

 the head, the fairly large eyes are provided, as in lizards, with 

 three eyelids, and behind each of them is a depression in which 

 the tympanic membrane is visible. Protection is afforded by a 

 number of horny plates united by their edges. The immobility 

 of the trunk is largely made up for by a fairly long and exceedingly 



Fig. 134. — Grecian Tortoise [Testudo Gr<2C€t) 



flexible neck, covered by soft skin. When retracted it is thrown 

 into an S-shaped curve. The stumpy limbs are adapted for 

 terrestrial locomotion, and can lift the body well off the ground. 

 As, however, the movements are extremely slow, defensive armour 

 is a necessity, and on the slightest alarm the animal withdraws 

 head, neck, tail, and limbs into the cover of the shell, when the 

 protective arrangements are completed by the horny plates on 

 the head and strong overlapping scales which are present on 

 the limbs. 



The usual limb-regions are present, though not well marked 

 externally, and the existence of five digits in either extremity 

 is indicated by a corresponding number of blunt claws. 



The exoskeleton resembles that of caimans, in that there are 



