VENOMOUS ANIMALS 



The genera of the CrotaUnse (Boiilenger) are: — Crotalus Linnaeus; Sistrurus 

 Garman; Ancistrodon Beauvois; Lachesis Daudin. 



There are two divisions of rattlesnakes in America — Crotalus and 

 Sis^mms— distinguished by the former having many small, and the 

 latter only nine large, scales on the top of the head. 



The best-known rattlesnakes are Crotalus horridus L., C. scutu- 

 latus Kenn, of Texas, C. confiuentus Say, of the Pacific, C. durissus 

 L., Cf cerastes Hallow. 



Fig. 39. — Skull of Crotalus horridus Linn^us. 



Note that in place of the long horizontal maxilla of the other three skulls 

 there is only a small vertical movable maxilla on each side of the anterior 

 part of the skull. It can be recognized by carrying the enormously developed 

 fang which is canalized and is virtually a hypodermic needle for the injection 

 of the venom. Note the reserve fangs, which should lie up against the skull. 



Fig. 40. — Side View of the Head Fig. 41. — End of the Tail of 

 OF A Rattlesnake (C. horridus). C. horridus to show the Rattle. 



Other genera are Ancistrodon, with Ancistrodon piscivorus Lacep., 

 the water moccasin, and A. contortrix L., the copper-head; Lachesis, 

 with I^achesis lanceolatus Lacep., the celebrated fer-de-lance of Mar- 

 tinique; L. anamallensis Gthr. and Sistrurus, with Sistrurus ravus 

 Cope and 5. miliarius L. 



Viperinse.- — The true vipers include: Viper a berus L., the adder 

 of England; V. russellii Shaw, the handsome viper of India and 

 Ceylon; Bitis arietans Merr,, the puff-adder of the Gold Coast; 

 Cerastes cornutus Forskal, the horned viper of North Africa; and 

 Echis carinatus Schn., the viper of the Pyramids, called ' efa.' 



The genera of the Viperinaei (Boulengcr) are" — Vipera Laurent; Causus 

 Wagler; Biiis Gray; Pseudoccrastes Boulenger; Cerastes Wagler; Echis 

 Merrem; Atheris Cope; Atractaspis Smith. 



