148 ZOOLOGY. 



1. Crotalus. Rattle-Snake. 5'cz/fa on the belly ; ffcw/fl and 



scales under the tail ; tail terminated by a number of 

 hollow, horny joints, loosely fitted into each other, and 

 which, on the slightest movement of the Animal, make 

 a rattling sound ; from whence its name. 



The whole of this genus, are highly poisonous, and stand 

 pre-eminent in point of danger, the bite frequently proving 

 fatal in a few hours, the poison is situated at the base of 

 their canine teeth, and is contained in sacks, which communi- 

 cate with apertures on the inner side of the fangs, at a short 

 distance from their points ; the poison is pressed from the 

 sacks, at the instant the animal inflicts its wound, and enters 

 with the teeth into the part bitten. These are generally 

 inactive, frequenting retired woods, are mostly natives of 

 America; some kinds grow to a considerable size. 



2. Boa. Scuta on the belly and beneath the tail» 



Some of this genera are the largest of the Serpent tribe, 

 having been known to attain the length of from thirty to 

 forty feet ; they inhabit the interior of Africa, India, South 

 America, and the Isles situated in the Indian Ocean ; they are 

 the terror of the inhabitants ; preying on almost every kind 

 of Animal that ventures near their retreats ; as Cattle, Deer, 

 and sometimes Man. None of the genus are poisonous. 



3. Coluber. Viper. Scuta on the belly ; broad alternate 

 scales under the tail. 



A very numerous tribe, nearly one half of which posses* 



