206 Zoologica: N. Y. Zoological Society. [I; 11 



snakes with fangs the habit of constriction disappears. It is noted 

 to a slight extent with the Opisthoglypha. Among the Proteroglypha 

 there is but an occasional hint of it, while with the highly specialized 

 Solenoglypha* it is altogether absent. 



We will consider the poisonous serpents in the following order: 



Two series of the Colubridae, thus: 



Opisthoglypha: Grooved fangs situated posteriorly. 

 Proteroglypha: Short, rigid, venom-conducting fangs 

 developed with internal canal and orifice at tip; 

 the fangs situated anteriorly. 

 Two subfamilies forming the Viperidae: 



The Viperinae and the Crotalinae, with greatly 

 enlarged anterior fangs, that are attached to 

 movable bones. 



The Opisthoglyph snakes form a series to which comparatively 

 little study has been devoted. While simpler descriptions have 

 tended to place them among the innocuous species, they are provided 

 with a well-developed fang mechanism and a poison highly efficacious 

 in subduing the prey. A considerable number of the species are of 

 insignificant size, consequently possessing almost microscopic fangs. 

 Some species are large enough to be dangerous to man. The anat- 

 omy of the poison apparatus is reversed from that of all other types 

 of venomous snakes, the fangs being furrowed or grooved, and situ- 

 ated in the extreme rear of the upper jaw; while the poison glands are 

 contained within the labial, instead of the temporal region. These 

 snakes may have one, or several pairs of fangs. To imbed these 

 venom-conducting teeth, an Opisthoglyph snake must advance the 

 jaws in a series of the familiar "chewing" motions characteristic of 

 serpents. When the fangs are brought into play, the jaws grip hard. 

 This persistent hold enables the poison to flow down the furrow of the 

 tooth and into the wound. 



The writer has made careful note of the feeding habits of snakes of 

 this type that have come to the Reptile House. A considerable number 

 of the Opisthoglyphs are of aboreal habits and it is representatives 

 of this kind the writer has induced to feed. Most of our aboreal 

 species preferred lizards. The attack is a deliberate stalk, the neck 

 is doubled into a lateral loop and the serpent strikes with great 

 rapidity, apparently aiming to secure the victim by the head. The 

 jaws are advanced until the fangs are well imbedded and the prey is 

 killed in significantly quick fashion. The venom appears to act upon 



*Members of the Viperidae — the rattlesnakes, copperhead and moccasin; 

 the Old World vipers. 



