SEllPENTS. 323 



range is coextensive with the whole United States, and whose best 

 known exponents are the ribbon-snake (T. [Eutsenia] saurita), water- 

 snake or adder (T. sipedon), and garter (T. [Eutasnia] sirtalis), the 

 first two abundant in the region east of the Mississippi, and the last 

 found almost everywhere from Canada and Nova Scotia to Mexico 

 and Panama. 3. Coluber, whose range is no less extensive than 

 that of the water-snakes, and which embraces among other forms 

 the most broadly distributed black-snake or constrictor (C. [Basca- 

 nium] constrictor) and the coachwhip-snake (C. iiagelliformis) of 

 the Southern States. 3. Pityophis, pine-snakes. 4. Elaphis, to 

 which the spotted racer (E. [Scotophis] guttatus), chicken-snake (E. 

 quadrivittatus), and pilot (E. obsoletus) belong, the first two prin- 

 cipally from the Southern States, and the last generally distributed 

 over the Atlantic border, from New England to Alabama. 5. Ophi- 

 bolus, king-snakes, whose species are widely diffused throughout 

 the United States, and whose best known representatives are the 

 southern chain-snake (O. getulus) — with a western variety known 

 as the king-snake (O. Sayi) — the red-snake (O. doliatus), and the 

 very common milk-snake or spotted adder (O. triangulus), whose 

 range extends from the Atlantic border to the Mississippi, and 

 northward to Canada ; and, 6. Diadophis, ring-necked snakes, rang- 

 ing nearly through the entire continent south of the Canadian line. 

 The genus Cyclophis comprises two common species of green- 

 er grass-snake, the summer-snake (C. sestivus) and spring-snake 

 (C. vernalis), both of which have a very extensive distribution. 

 Two species of hog-nose snake (Heterodon) occupy a considerable 

 part of the United States, and are locally known as blowing-vipers 

 or adders. 



The remaining colubrine forms are embraced in genera largely 

 limited as to the number of species, and which in many cases, as in 

 Contia, Tantilla, Sonora, &c., are confined to the transition-tract 

 which unites with the Neotropical realm. The North American 

 crotaloids are comprised in three or more genera: Crotalus, the 

 rattlesnakes proper, Sistrurus (or Crotalophorus), the prairie or 

 grass rattlesnakes, which are confined principally to the Central 

 and Southern United States, and Ancistrodon, the copperheads and 

 moccasins. Of the last there are three species : A. contortrix, the 

 copperhead, whose habitat is the greater part of the region east of 

 the Mississippi; A. piscivorus, the true or water moccasin, which 



