LIZARDS. 127 



" Although I have alluded to the sun's influence 

 as being the means of hastening the evolution of 

 the embryo in the oviparous reptiles, it is not to 

 be concluded that the same source of warmth is 

 unnecessary in the present and similar instances. 

 The only difference is, that in the ovo-viviparous 

 species the solar heat is communicated to the em- 

 bryo through the medium of the mother ; and 

 hence we often see the pregnant female, about 

 the month of June, constantly basking in the sun, 

 and lying in such a position as to expose the body 

 most fully to his influence. Every one who has 

 watched the habits of our native reptiles must 

 have seen the same circumstance in the gravid 

 female of the Common Viper, and may have ob- 

 served how much more reluctantly and tardily she 

 leaves the genial spot than the male."* 



Mr. W. C. L. Martin also thus speaks of the 



agile movements of this pretty and familiar little 



reptile : — " It is astonishing to see how rapidly, 



when alarmed, these agile little creatures gain 



their burrows, or disappear from view, diving 



beneath the intertangled vegetation : they seem 



gone in the twinkling of an eye. Not less prompt 



and rapid are they in catching their prey ; the 



moment an insect comes near them, or settles on 



a leaf within due distance, their bright eyes mark 



it ; the next instant it is seized and swallowed : 



the act is wonderfully quick and instantaneous. 



The sight of these animals is indeed very acute, 



and their hearing appears also to be by no means 



deficient ; we have seen them on the slightest 



noise, on the snapping of a branch, or a rustle 



made among the leaves, dart off to their burrows, 



* Brit. Kept. 34. 



