CHAPTER II. 

 MORPHOLOGY OF VENOMOUS SNAKES. 



That mere external general appearances are not sufficient to distinguish a 

 poisonous snake from an innocuous kind has long been known. Indeed, 

 our natural instinct to fear every form of snake, notwithstanding the beauti- 

 ful coloration of some species, may have had its origin in a series of accidents 

 resulting from a reckless approach to the innocent-looking poisonous snakes. 

 A brief description, therefore, of various individual superfamilies, families, 

 subfamilies, genera, and species of the venomous snakes may be useful. 



In describing the poisonous snakes the zoological order has been adopted, 

 commencing with the Opisthoglypha. For the purposes of this work it has 

 not been found advantageous to follow any one authority as to nomenclature 

 and classification, but no confusion need arise from this, as in most instances 

 the authority is indicated. The system of Boulenger is more often employed 

 in the Asiatic, African, and European snakes, while Cope's classification is 

 more frequently used in the American varieties. The exact description of 

 various Oriental snakes is derived from the excellent work of Stejneger. 



Family COLUBRDXa: Boulenger. 

 OPISTHOGLYPHA. 



Plate i, A and B. 



This is Cope's equivalent. Superfamily Glyphodonta; family Dipsadida;. 



Dryophidse of authors must be included under this heading. Tragops prasirms Wagler and perhaps 

 Dryophis prasina of authors, which comes under Dryophidae, inhabits East India and has 

 a powerful venom; it is Opisthoglyphous. Dryophis Boie and Dryitms Merren are identical 

 and have no elongated median maxillary teeth anterior to the elongated posterior grooved teeth. 

 Dryophis Boie is not identical with Dryophis Wagler. 



Family characters: One, or more, of the posterior teeth of the maxillary bone 

 have a groove or furrow running frontally from base to apex, and conduct the 

 secretion of the modified supralabial gland. Their zoological position is between 

 the harmless and the powerfully venomous members of Colubridae. The venom 

 is usually trifling in amount, but powerful, often killing lizards in a very short 

 time. Their comparative inoffensiveness must largely be due to the situation of 

 the poison fangs, which is unfavorable for inserting them into a victim. The 

 family includes 79 genera and about 300 species. 



This family contains forms of very varied habits, arboreal, terrestrial, subter- 

 ranean, and aquatic. Cosmopolitan, excepting New Zealand. 



Subfamily DIPSADOMORPHIN.S: Boulenger. 



Boiginae Stejneger. Dipsadinse Cope. 



Teeth well developed, nostrils lateral. 



Some forms are arboreal, others terrestrial, and all have a long tail. The colora- 

 tion of the arboreal is green above, often with white or yellow longitudinal bands, 

 and white or yellow underneath. Their food consists chiefly of lizards, birds, and 

 eggs. The following genera represent their corresponding types: 



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