66 VIPERADA. 
Although there is no reason to believe that the Viper 
employs this powerful means of destruction for the purpose 
of disabling its prey before it is finally seized; but, on the 
contrary, all the observations which have been made upon — 
its mode of feeding, tend to shew that, like the Snake, it 
seizes its prey at once, and immediately begins to swallow 
it; yet it is not at all improbable, considering how instant- 
aneously the poison begins to affect small animalsy.that 
even in the act of seizing a mouse or bird, or any other 
victim, it may instil a sufficient quantity of venom into 
its system to paralyze and presently destroy it. Still the 
action by which it takes its prey is very different from 
that which it employs in its defensive attack, and resem- 
bles that employed by the innocuous tribes. Its favourite 
food consists of the smaller mammalia, field-mice, shrews, 
and similar little animals, of frogs also, though less com- 
monly, and occasionally of birds. It does not always con- 
fine its voracity within the limits of its powers of deglu- 
tition ; for I have in my possession a specimen of a small 
Viper which was taken on Poole Heath in Dorsetshire, in 
a dying state, in the act of attempting to swallow a mouse 
which was too large for it, the skin of the neck being so 
distended as to have burst in several places. 
The Viper, like many others of the poisonous groups of 
Serpents, is ovo-viviparous. I have concluded, from the 
examination of many specimens, both of this species and of 
the Rattlesnake, that it is in the act of parturition that the 
membrane of the egg is burst. I have examined several in 
which the young have appeared ready to be excluded; 
but have always found the investing membrane entire ; 
although so thin and soft as to be torn by the slightest 
force. I give a figure of the young Viper in this state, 
the membrane having been removed. It is coiled up so 
