200 Zoological N. Y. Zoological Society. [I; 11 



proceeds. Typical representatives are Colubrine snakes, 

 Spilotes, Zamenis and allied genera. 



Non-Constrictors: Serpents that swallow the living prey with- 

 out effort to subdue it by bodily manipulation. A great num- 

 ber of such species are characterized by their possession of en- 

 larged posterior teeth to permit a firmer hold of the quarry. 

 Members of numerous Colubrine genera: Tropidonotus, 

 Eutaenia and Heterodon are typical in the exhibition of this 

 habit. 



VENOMOUS 



Among the poisonous snakes, we consider three types, viz. : the 

 members of the Opisthoglypha and the Proteroglypha of the Colu- 

 bridae, and the long-fanged members of the Viperidae. Two well- 

 defined methods of killing the prey may be noted: 



a. The snake seizes the quarry and by a gripping movement of the 

 jaws imbeds the fangs. The bitten animal is thus held until dead, when 

 deglutition begins. A few species are constrictors, but possess little 

 bodily power. These habits are typical of the venomous Colubridae, 

 viz. , the members of the subfamilies, Homalopsinae, Dipsadomorphinae, 

 Hydrophiinae and Elapinae. The shorter-fanged members of the Viper- 

 idae feed in similar fashion, particularly those species that feed upon 

 birds, lizards or batrachians. 



b. Serpents that stab their prey and immediately release it, await- 

 ing its rapid death by poisoning. This habit appears to be confined to 

 the long-fanged members of the Viperidae. Typical genera are Crotalus 

 and Bitis. While this is an almost invariable habit among captive ex- 

 amples of the genera, it must also be understood that such reptiles 

 are excessively nervous and their feeding when wild — particularly in 

 the treatment of smaller prey — may be similar to group "a". 



By this summary we may note the characteristic feeding traits 

 of serpents. Considering these from the standpoint of zoological 

 arrangement of families, we observe little of significance as regards 

 classification, except among the highly specialized forms which have 

 acquired their remarkable venom-conducting teeth and deadly poi- 

 son. In the process of evolution away from the lacertilian form, the 

 snakes have acquired, with the elongation of their limbless bodies, a 

 characteristic which appears to be unique among the Ophidia, when 

 applied to the killing of the prey. This is constriction, a power which 

 the writer has noted among lizards, but apparently put to no specific 

 use. When handled, the worm-like lizards of the Ampkishxnidae 



