The Opisthoglyph Snakes of North America 



members are of diminuti\e proportions. They inhabit the 

 southern portions of the United States, Mexico, Central America 

 and South America. Most of the species have a pale brown 

 body and a black head. 



The body is slender, with about fifteen rows of smooth, 

 opalescent scales; the head is flat and not distinct from the neck. 

 In front of the eye is a single plate (preocular). The loreal plate 

 is lacking. (See Figure.) 



These tiny serpents are provided with the usual dentition 

 of the Opisthoglyph snakes — grooved fangs on the rear portion of 

 the upper jaw, but may be classed among the reptiles innocuous 

 to man as their microscopic teeth would be unable to draw blood. 



The species of Tantilla lead a secretive, or burrowing life. 



A concise list, only, is given of these serpents: 



General Colouration. — Body brown; head blackish. 



A. Seven upper lip plates (superior labials). 



a. A yellow or white ring at base of head. 

 Yellow ring followed by a broader ring of black. 



CROWNED SNAKE, T. coronatd, (B. & .G.) 



Dimensions. — Length 9 inches. 



Tail If " 



Diameter A " 



Width of Head T¥ " 



Length of Head -^^ " 



Distribution. — Southeastern States. South Carolina 

 to Florida (inclusive) ; westward to Mississippi. 

 Yellow ring bordered in rear by black dots. 



eisen's black-headed snake, T. eiseni, (Stejneger.) 

 Distribution — Seven specimens known; all captured 

 twenty-five years ago, at Fresno, California. 



b. No yellow ring at base of head. 



TEXAS black-headed SNAKE, T. nigriccps, (Kennicott). 

 Distribution. — Texas and New Mexico. 



B. Si.x upper lip plates. 



Colouration like the preceding species. 



SLENDER BLACK-HEADED SNAKE, T. graciUs, (B. & G.) 



Distribution. — Missouri to Texas. 



Among these North American Opisthoglyph snakes, the species 

 of Trimorphodon and Sibon alone, are actually dangerous. For- 

 tunately, they are easy to recognise by the distinct head and 

 cat-like eye. Compared with the other — degenerate — snakes 

 of the kind inhabiting the United States, they are unique. 



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