INTRODUCTION. XIX 



sufficient to warrant the belief. Instances reported to the writer concerned 

 some known to be snake-eaters; others known to lay eggs, paying no farther 

 attention to them, and others of undeterminable species noticed by incom- 

 petent observers. 



The Museum of Comparative Zoology possesses a specimen of Coluber 

 constrictor, the "Black Snake," taken in Essex county, Massachusetts, by 

 Prof. Putnam, the stomach of which contained a half-digested specimen 

 of Cyclopias vernal is, the "Green Snake," and another of Storeria dekayi, 

 DeKay's "Brown Snake." It is a well established fact that this snake and 

 others feed upon their own species at times. Specimens of viviparous 

 species, in which the young were about ready for delivery, have led some to 

 the mistaken belief that the little ones had been swallowed. 



The classification adopted in the following synopsis includes all serpents 

 in four groups or suborders: Scolecophidia, worm snakes ; Onychophidia, 

 clawed snakes ; Acacophldia harmless snakes ; Toxicophidia, venomous 

 snakes. 



Scolecophidia. 



Those of the first suborder are subcylindrical, wormlike, burrowing 

 species, which feed upon worms, larvae of insects, and the like, living 

 beneath the surface of the ground. The body is usually elongate, and 

 the tail short and thick. On account of their subterranean habits, the 

 eyes are protected by thickened plates, and are more or less imperfectly 

 developed. Probably it is by the sense of smell that the presence of food 

 is detected. The mouth is comparatively small, and the bones of the skull 

 are more firmly articulated than in other Ophidians. There is great simi- 

 larity between the scales of the back and those of the ventral surface. 

 The body is marked by a certain rigidity, necessary in burrowing, which 

 makes these snakes very awkward travelers upon the surface of the ground. 

 As if to aid in pushing, the tail is in cases provided with a sharp spine, 

 and in others it is truncate and tubercular. Venomous Scolecophidia are 

 unknown. North American representatives of the group are found in ten 

 or eleven species of the family Typlilopidm. They range from California 

 and Texas southward and westward. Worm snakes belong to tropical 

 and subtropical regions of both hemispheres. Certain species possess a 

 rudimentary pelvis. 



