BOAS; PYTHONS. CROTALID*. 571 



of the hinder limbs, in their position and attachments ; these 

 claws are put in action by powerful muscles, and serve as a kind 

 of antagonist to the tail in grasping any object. The true Boas 

 are restricted to America ; the name of Python being given to 

 the large Serpents of Africa and India. There is no doubt that 

 individuals of both genera occasionally attain a size that enables 

 them to overpower and gorge animals of large size, such as Men 

 or Cattle ; but these are rarely met with, the usual length of 

 these Serpents being from 15 to 30 feet. It is related by Pliny, 

 that the army of Regulus was alarmed by a huge Serpent, whose 

 length was 123 feet ; but it is doubtful how far this account is 

 to be relied on. A well-authenticated instance has occurred in 

 recent times, however, of the destruction of a Snake above 62 

 feet long, whilst in the act of coiling itself round the body of a 

 man. After having destroyed the life of their victims by the 

 compression of the body, these huge Snakes proceed to envelope 

 them whole in their capacious swallow; and owing to the re- 

 markable power of distention, which the jaws and oesophagus 

 possess, even the bodies of men and cattle can be thus engulfed. 

 After gorging themselves to a degree which causes the skin of 

 the neck to appear as if it would burst, they retire to their hiding 

 places, and there continue in an almost torpid state, until the 

 process of digestion has been completed ; after this period (which 

 sometimes lasts a month) is over, the Snake again issues forth in 

 search of its prey. The Boas of America seem to have been 

 tamed by the ancient Mexicans ; and to have been especially 

 used by the priests, as instruments for impressing the people with 

 awe and reverence for their power. 



509. The section of Poisonous Snakes also contains two 

 families, the CROTALID.E, or Rattle- Snakes, and the VIPERID^E, 

 or Vipers. The true Rattle- Snakes, distinguished by the peculiar 

 appendage to their tails from which their name is derived, are 

 confined to America ; but there are other species, included in the 

 family CROTALID^E, which are found in the Old World also. 

 The rattle consists of a number of thin horny cells, which are 

 articulated loosely to each other, and which produce a rustling 

 noise when shaken. The number of joints increases, up to a 



