REPTILIA 263 



to the jaw; but the hollow fang is folded against the upper 

 jaw when not in use and becomes erect when the mouth is 

 opened to strike. Snakes continually protrude the forked 

 tongue when they are moving about and this habit has 

 often led to the belief that the tongue is the fang or "sting," 

 an idea which is of course erroneous. 



In the United States there are only five kinds of poisonous 

 snakes: coral snakes, water moccasin, copperhead, rattle 

 snakes, and opisthoglyphs. Two species of coral snakes 

 (Flaps) are found in the south. They are banded with 

 red, black, and yellow, and have grooved fangs. Four 

 species of opisthoglyphs are found along the southern 

 border of the United States. They are small snakes with 

 grooved fangs which are set far back in the mouth. They 

 cannot readily inject poison by striking quickly at an 

 animal, but must take the prey into the mouth to kill it. 

 The other three types range farther north, have hollow 

 fangs, and belong to the group of venomous snakes known 

 as pit vipers. In these there is a well-defined depression 

 on either side of the head between the nostril and the eye. 

 The water moccasin or cotton-mouth (Ancistrodon pisci- 

 vorus) is a semi-aquatic serpent which frequents the 

 lagoons and sluggish waterways in the southeastern states. 

 It averages about four feet in length but may reach six. 

 The body is very stout and heavy, with an abruptly taper- 

 ing tail and a chunky, ugly head. The copperhead (Ancis- 

 trodon contorlrix) is found east of the Mississippi River from 

 Massachusetts to Florida. It frequents forests and planta- 

 tions, hiding among fallen leaves which it closely resembles 

 in color. There are nineteen species of rattle snakes and 

 the majority of them are found in the United States and 

 Mexico. The diamond-back (Crotalus adamateus) of the 

 /southeastern states is the largest and most deadly of our 

 native serpents. The rattle is an unique organ among 

 snakes. ' The little bells which compose it are formed each 

 time the skin is shed, and are not closely indicative of the 

 snake's age. 



