84 



OPHIDIAN EEPTILES. 



articulated one into the other. When the animal advances these 

 little capsules resound slightly, like the dry husks of beans which 

 still retain their seeds, thus giving notice of the approach of this 

 terrible enemy. The sibilant rattle of these appendages is not 

 very loud, but it may be heard about thirty paces off, aind announces 

 the approach of the reptile while it is still at that distance. 



Fig. 20. Northern Eattlesnake ( Uropsophus durissus). 



Rattlesnakes feed on small mammals and upon other reptiles, wait- 

 ing patiently for their approach ; when close to them, the Rattle- 

 snake throws itself upon them. They are oviparous ; and for some 

 time after they are hatched, the young are said to seek a refuge in 

 the mouth of their mother. During summer Rattlesnakes remain in 

 the midst of stony mountains, uncultivated places, or places covered 

 with wild wood ; they generally choose those parts most exposed 

 to the heat, the sunny shores of a fountain or stream where small 

 animals come to drink. They like also to place thmeselves under the 

 shadow of an old fallen tree. Audubon, the celebrated ornitho- 

 logist, says that he has often met with Rattlesnakes rolled up in a 



