VERTEBRATA : REPTILIA. 



549 



dangerous and venomous animal, but quite erroneously, as it is even un- 

 able to pierce the human skin. It is a perfectly harmless animal, living 

 upon worms, insects, and snails, and hibernating during the winter. It 

 derives its specific name of fragilis from the fact that when alarmed it 

 stiffens its muscles to such an extent that the tail can be readily broken off, 

 as if it were brittle. 



Numerous other small Lizards are referable to the Scincidce, but it is 

 only necessary to mention the Skinks themselves (Scincus}, in which both 

 pairs of limbs are present in a well-developed state. The Skinks are found 

 in almost all the warmer parts of the Old World, and closely-allied forms 

 (such as the West Indian "Galliwasp") are found in the New World. 

 The common Skink (fig. 303) is a native of Arabia and Africa. It attains 

 a length of eight or nine inches, and was formerly used in various diseases 

 as a remedy. 



Passing over several small groups, the next family requiring 

 consideration is that of the Lacertida, comprising the typical 

 Lizards, in which there are always four well-developed limbs, 



Fig- 303- The common Skink (Scincus ojfficinalis). 



each terminated by five free toes of unequal lengths. The 

 body is covered with scales, which assume the form of shields 

 or "scuta" over the abdomen and on the head, the scales of 

 the former region being square and arranged in transverse 

 bands. The tail is rounded. The tongue is slender, bifid, 

 and protrusible, and the eyes have distinct lids. The only 

 truly British Lizards are the Sand-lizard (Lacerta agilis) and 

 the Viviparous Lizard (Zootoca vivipara) ; and the commonest 

 form upon the Continent is the graceful little Green Lizard 

 (Lacerta viridis\ which also occurs in Jersey. The Lizards of 



