41 o . SNAKES. 



frog one day. It did not regularly constrict it in order to 

 kill it ; but wheti caught in the mouth, it helped itself to 

 restrain the straggling limbs by a few coils. Dr. Wucherer 

 affirms that he had never seen its congeners LiopJiis or 

 Xenodon squeeze or coil themselves round their prey, but 

 Heterodon d' Orbignyi certainly does. 



Another peculiarity of the American Heterodoiis is that of 

 flattening their heads and the upper part of the body when 

 angry or molested. It is this, together with their pseudo- 

 fangs, that have procured them the name of ' spread-head,' 

 ' spreading-adder,' 'puffing-adder' or 'blowing viper,' — ■ 

 because at the same time they hiss violently, — or simply 

 * the adder,' and ' biausser,' or the blower. 



There are several species of them, all, with the exception 

 of H. d'Orbignyi, having undeniably ugly, viperish-looking 

 heads, * Angiiis capites viperinol or ' Serpent a la iete de vipere! 

 The snout terminates in a large, conspicuous, recurved scale 

 which gives them a pug-nosed or rather a hog-nosed appear- 

 ance. Catesby, who was the first to describe the ' hog-nosed 

 snake,' said ' it hath a visage terrible and ugly.' In H. niger 

 and H.platirJmios this is most apparent. They belong mostly 

 to the New World, both north and south. One in Virginia 

 is called, from its bright markings, the ' calico snake,' the 

 word calico in America being applied chiefly to coloured 

 prints used for dresses. Another is called ' the mountain 

 moccasin,' the latter name in the United States being 

 applied to venomous kinds. 



In the flattening of the head and body, Xenodon and 

 Heterodon approach the cobras ; in the strange dentition 

 they approach the vipers ; in their true nature they are 



