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



The development of the nervous organization appears to play an 

 important part in the feeding habits. The most highly specialized 

 types, the viperine poisonous snakes, possess a highly sensitive nerv- 

 ous organization and for the most part are short-lived under obser- 

 vation. It is among these reptiles that we note mystifying habits, 

 and among representatives of some of the species, an utter disinclina- 

 tion to feed. Though provided with deadly, venom-conducting 

 fangs, and an amazing dexterity in the use of these weapons both in 

 obtaining food and in defense, these formidable creatures invariably 

 remain more timid than their innocuous allies which become readily 

 accustomed to change of environment. 



In preparing this resume of a considerable series of genera and 

 species, the writer hopes that it may contribute something toward a 

 solution of some of the problems of evolution and relationship which 

 fall to the lot of the systematist. 



While considering the feeding habits of an extensive order like the 

 Ophidia, some of the members of which cling to ancestral character- 

 istics, while others have become highly specialized, a first im- 

 pression might lead the novice to presuppose the existence of a great 

 variety of foods. This is not actually the case. The food of serpents 

 is considerably less elaborate than of the Order that embraces the 

 ancestral forms of the snakes, the lizards. The point of primary 

 importance to be noted is the fact that serpents are carnivorous and 

 a few insectivorous; no species of snake is known to be herbivorous. 

 Among the lizards the herbivorous species exist in large number. 

 This is also the case with the latter Order in regard to insectivorous 

 species. There are few species of insectivorous serpents, however, 

 and the habit is noted as occurring arbitrarily among both small 

 species of directly ancient lineage and others which are markedly 

 specialized. 



The great percentage of serpents feed upon forms of vertebrate 

 life. A large number feed exclusively upon mammals and birds, and 

 a like proportion subsist entirely upon cold-blooded vertebrates. 

 There are many species with feeding habits not so well defined and 

 which feed upon either mammals, birds, reptiles or batrachians; 

 these we will term omni-carnivorous species. Many species are 

 cannibalistic and a few feed altogether upon eggs. 



In the development of serpent life, even among the crudest forms, 

 we immediately note the great modification of the structure of the 



