VIVIPAROUS LIZARD. 37 
Continent its range does not appear to be very extensive : 
it is not found in Italy, nor, I believe, in France, and is 
very probably confined in a great measure to our own 
latitude. Its movements are beautifully graceful as well 
as rapid; it comes out of its hiding-place during the warm 
parts of the day from the early spring till autumn has far 
advanced, basking in the sun, and turning its head with a 
sudden motion the instant that an insect comes within its 
view, and darting like lightning upon its prey, it seizes it 
with its little sharp teeth and speedily swallows it. Thus 
it will often take a great number of the smaller insects, 
preferring those of the dipterous order; though it will not 
refuse many of the coleoptera or orthoptera, if they be not 
too large. 
Instead of depositing her eggs in the sand to be hatched 
by the warmth of the sun, as is the case with the former, 
the female of the present species retains the eggs within 
the oviduct until the young are ready to leave them, and 
thus they are produced alive. As in all the ovo-vivipa- 
rous reptiles, the covering of the egg is very thin, and 
merely membranous. In this respect they differ from 
those which deposit their eggs before the embryo is formed. 
In the latter case a more efficient protection is necessary, 
and the covering is either calcareous, as in the Tortoises 
and Crocodiles, or of a substance resembling parchment, as 
those of the Snakes and most Lizards. In the Viper, 
which also produces its young alive, the covering, as in the 
present animal, is extremely thin and very easily torn ; 
and there is reason to believe that the laceration of this 
membrane and the emancipation of the young take place 
in and are occasioned by the very act of parturition. 
As the young ones are occasionally found with the 
mother, there is some reason to believe that these little 
