256 CLASS REPTILIA. 



The Crotali, (Crotalus, Lin.) vulgarly, Rattle- 

 snakes, 



Are celebrated above all other serpents for the fatal 

 subtlety of then' poison. Like the boa, they have 

 simple transverse plates under the body and tail. 

 But what best distinguishes them is the noisy 

 instrument which they carry under the tail, and 

 which is formed of many scaly cornets embossed 

 loosely in each other, which move and resound 

 when the animal moves his tail. It appears that 

 the number of these cornets increases with age, and 

 that there remains an additional one at each moult- 

 ing. The muzzle of these serpents is hollowed with 

 a small round fosset behind each nostril. All the 

 species, whose country is well known, come from 

 America. They are more dangerous in proportion 

 to the heat of the climate or season. But their 

 natural disposition is in general tranquil, and rather 

 lethargic. 



The rattle-snake crawls slowly, does not bite 

 except when provoked, or for the purpose of killing 

 its prey. 



Though it does not climb on trees, it neverthe- 

 less makes its principal food of birds, squirrels, &c. 

 It was for a long time believed that it had the power 

 of torpifying them by its breath, and even of fasci- 

 nating, that is, of forcing them by its glance alone 

 to precipitate themselves into its mouth. It appears, 

 however, that it is enabled to seize them, only 



