xx inteoduction-. 



Onychophidia. 



Serpents of the second suborder, Onychophidia, are distinguished by rudi- 

 mentary posterior limbs, the only external evidence of which is a small 

 claw or prominence on each side of the vent. This group contains the 

 largest of the snakes, the Boas and Anacondas of the Americas and the 

 incubating Pythons of the old world, species of which are said to reach 

 a length greater than thirty feet. The section of the group containing 

 species with thick non-prehensile tails is represented in California and 

 Mexico by several burrowing snakes belonging to the genus Charina of 

 the Erycidce. Eunectes, containing the Anacondas, is a South American 

 genus, and its species reach greater size than other new world snakes ; it 

 belongs to the section with prehensile tails. Of this section there are three 

 species of Boa in Mexico ; a doubtful fourth is reported in the Yellow Boa, 

 Chilabothrus inomatus, properly of the West Indies. Tbese Onychophidia 

 are expert climbers, and many are equally active in the water. None of 

 them are venomous. They are able to swallow animals of much greater 

 diameter than their own. Ordinarily they seize the prey with the teeth 

 and crush it in folds of the body. 



Acacophidia. 



The innocuous snakes comprise all the common, harmless species of the 

 ground, fresh water, or trees. Being not at all harmful, and feeding on 

 mice, moles, insects, etc., many of them are important aids in restraining 

 the increase of the most destructive enemies of the husbandman. The 

 vulgar fear of these animals is mainly the result of education or of preju- 

 dice, which lacks foundation in facts. In reality, some of the most dreaded 

 have no existence. Such as the "Ring" or "Hoop Snake," which is said 

 to take the end of its tail in its mouth and roll over and over like a hoop, 

 killing everything it touches with its venomous horn, and the "Blow 

 Snake," the breath of which is deadly, are mere fictions. A few members 

 of the division prey upon others, and are said to conquer and eat species of 

 the Toxicophidia. 



Several are possessed of considerable curiosity, and sometimes follow 

 objects that have attracted their attention. The common black snake, 

 Coluber constrictor, occasionally chases men in this way, but if turned upon 

 at once seeks safety in flight. It happens at times that harmless species 



