232 



Zoologica: N. Y. Zoological Society 



[I; 11 



the genus Crotalus cover observations on living representatives of 

 twelve species. 



In the Old World, the Ancistrodon type has survived in the shape 

 of puny terrestrial forms, while the Lachesis (Trimeresurus) types 

 have become an extensive branch of mostly arboreal forms; among 

 all of them we find the food selection to cover cold-blooded prey as 

 well as small mammals and birds. 



The Viper inae: It is not apparent that this present subfamily 

 of the Viperinae, originating along a source involving the Crotalinae, 

 but represents a parallel type of development from a near source. 

 In lesser specialized forms, like Causus, appealing to the Coluhridae 

 in scalation of the head and quite remarkable in being oviparous, we 

 note an arbitrary habit as compared with the later forms in the food 

 selection of cold-blooded prey, although these snakes also feed upon 

 small mammals. Among the smaller species of Viper a, with the 

 larger head shields such as V. herus, there is a tendency to feed upon 

 lizards besides small mammals. Coming to the highly specialized 

 forms like Bitis and Atheris, we note the same positive restriction of 

 food to warm-blooded prey as described to exist among the later 

 Crotalines. 



As a comparative review of the food selection of serpents, the 

 writer has prepared a table that follows and which includes only those 

 species under thorough observation and represented by a generous 

 number of examples. The term omni-carnivorous is used to concisely 

 designate those species which feed upon both warm and cold-blooded 

 prey. Species of pronounced economic value are marked.* 



CHARACTER OF FOOD** 



Family glauconiidae 

 Glauconia alhifrons .... 



Family boidae 

 Subfamily Pythoninae 



Python reticulatus t , 



" molurus I 



se6«t 



" regius'\ 



Warm-blooded 



Mammals and birds 



Cold-blooded 



Lar0e Lizards 



Invertebrates 



Insectivorous 



**See reference notes at end of schedule. 



