8 CROTALOIDEA. 
4, The gland that secretes the poison is situated near the eye, under the temporal 
muscle, so as to be compressed by its contraction. ‘The poison varies in 
intensity perhaps in the different genera, but more so according to the state 
of the animal. It is most active in the healthy snake—in the summer season 
—when it has been long retained—when the animal is greatly irritated, Wc. 
&c. To be deadly, however, it must be introduced into the circulation, for 
it can be taken into the stomach with impunity. 
5. These serpents are all viviparous; or, the egg is retained in the female until it 
is hatched, and the young animal is then expelled alive. 
