1912] Ditmars: Feeding Habits of Serpents 199 



jaw bones, this pointing to carnivorous habits. Among the highly 

 specialized types of the later groups, this modification has developed 

 into a structure that enables the serpent to easily manipulate its liv- 

 ing prey, without the use of the bodily coils. A number of snakes 

 thus swallow their prey alive, without resorting to constriction or 

 other means of overpowering it. 



Though the snakes are largely carnivorous, the methods of hunt- 

 ing and overpowering the prey differ widely among the members of 

 the various families and genera. 



Part I. — Methods of Feeding 



Snakes practice various methods in killing their prey, but these 

 widely different habits are displayed as unvarying characteristics 

 among the members of genera and families. In some families, such 

 as the cosmopolitan Colubridae with its several subfamilies, there 

 exists every method of subduing the prey that is to be noted among 

 snakes. Among the members of other families, the manipulation of 

 the freshly captured prey is usually of a respectively unvarying char- 

 acter. Such families may represent the older types or those of 

 marked specialization. Accordingly, from the viewpoint of their 

 feeding habits, the serpents may be crudely divided into several 

 fairly well-defined groups, but owing to the variability of habits that 

 exists within occasional families, these groups are constructed merely 

 in systematizing the present article, not in accordance with zoological 

 classification. 



The suggested groups may be outlined as follows: 



NON-VENOMOUS 



Constricting species: Serpents of all sizes that kill their prey 

 by coiling about it and squeezing it to death. Members of 

 the Boidae and Colubridae. 



Semi-Constrictors: Species that swallow the living prey, but 

 subdue it by holding within a single coil or pressing it firmly 

 against the ground by a fold of the body while deglutition 



