36 GUIDE TO EEPTILES AND AMPHIBIANS. 



family are the Common Lizard (Lacerta vivipara), in which the 

 young (from 6 to 12 in number) burst the eggs just before or just 

 after they are laid, the Sand-Lizard (L. agilis, 443), the Green Lizard 

 (L. viridis, 442), the Wall-Lizard (L. muralis, 444), and the beautiful 

 Eyed Lizard (L. ocellata, 441, fig- 36). All of these are European, but 

 only the first two occur in England. The Spanish Lizard (Psammo- 

 dromus Mspanicus) represents a genus distinguished by the absence 

 of a semi-lunar collar of enlarged scales on the front of the neck. 



Yariation in the South European Wall-Lizard {Lacerta muralis) 

 is illustrated by coloured figures. 



The family Gerrhosauridm (438, 439) comprises a small assemblage 

 of African and Malagasy Lizards characterised by their pleurodont 

 dentition, the long and slightly cleft tongue, which is furnished with 

 tubercles, and the presence of bony plates in the skin of the head 

 and body, roofing over the temporal region of the skull. In addition 

 to the typical Gerrhosaurus (439), there are the genera Tetradactylus, 

 Cardylosaurus, Zonosaurus (438), and Tracheloptychus. 

 Fig. 37. 



iH&PulilTT) 



Stump-tailed Skink (Trachysaurus rugosus) ; £ nat. size. (No. 374)- 



Case 20. The Common Skink is the type of a large and cosmopolitan family 



of Lizards known as Scincidm (455-474), or Skinks, and presenting 

 the following characteristics. The dentition is pleurodont, i.e. the teeth 

 are attached to the inner side of the margin of the jaws ; the tongue 

 is scaly and but slightly notched ; and bony plates are developed in 

 the skin of the head and body. Skinks prefer dry sandy ground, on 

 which they move rapidly and in which they burrow ; the frequent 

 reduction or even loss of the limbs being connected with the 

 burrowing habit. Most produce their young alive ; the usual hard 



