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NATURAL HISTORY. 



Order II OPHIDIA.(G\\ "O$ir, a Serpent.) 



Sxib-order I. VIPERINA. (Lat. Viper a, a Viper.) 

 Family I. . . Crotalidae. (Gr. Kpora/W, a Rattle.) 



UROPSOPHUS. (Gr. Ovpd, the tail; i/;o</>or, a noise.) 



Durissus (Lat. durus, harsh), the Rattle-snake. 



THE peculiar gliding 1 movements of the Snakes render them 

 excellent types of the Reptiles, a word derived from the Latin 

 repo, I creep. The extraordinary flexibility of their bodies is 

 caused by the structure of their vertebras, each one of which fits 

 into the one behind it by a ball-and-socket joint, thus allowing 

 freedom of motion in every direction. 



The RATTLE-SNAKE is a native of America. Its name is de- 

 rived from the loose bony structure at the extremity of its tail, 

 called the rattle, and which by the sound of its movements gives 

 timely intimation of the vicinity of this terrible reptile. Fortu- 

 nately, its disposition is exceedingly sluggish, and it invariably 

 sounds its rattle when irritated or disturbed. Its bite is inevi- 

 tably mortal, and death always ensues within a few hours after 

 its bite. 



The deadly weapons with which the venomous serpents 

 are armed, are two long curved fangs belonging to the upper 

 jaw, and moving on a hinge by which they lie flat in the 



