THE RATTLESNAKE 129 



perfectly smootli surface it can make no advance at all. 

 It is common enough to see serpents represented in 

 ligures as bending their body in a series of vertical folds. 

 This is another mistake. A snake's body can be bent 

 only from side to side. 



The rattlesnakes form part of a small group of serpents 

 some of which have no rattle. They all agree, however, 

 in being very poisonous and in having the curious pit 

 already described as placed between the nose and the 

 eye. The whole group (rattlesnakes included) are there- 

 fore spoken of as " pit vipers." Some of the pit vipers 

 which are not rattlesnakes are found in the Old World, 

 while others are (like rattlesnakes) American reptiles. 

 Among the latter are the copperhead and water-moccasin 

 of the Carolinasand Texas (so dreaded by workers in rice 

 plantations), and the even more ferocious fer-de-lance of 

 the West Indies, which attacks without wai-ning, and is 

 said to have been the main cause of death among the 

 labourers in sugar plantations, wherein it finds shelter 

 and often multiplies prodigiously. Lastly may be men- 

 tioned Bushmaster (Lachesis) of tropical America, which 

 seems to be the largest poisonous land snake known, 

 as it is said to be sometimes fourteen feet long. In the 

 Old World a dozen species of pit vipers are found, in 

 India one species ascending as high as 10,000 feet above 

 the sea in the Himalayan mountains. 



The whole group of pit vipers, including the rattlesnakes, 

 forms but one subordinate section of the great order of 

 serpents, which order contains as many as 1500 species 

 at the least. These are generally divided into the 

 poisonous and non-poisonous snakes ; but such a division 

 is not a natural one, for some poisonous snakes are 

 much more closely related to the non-poisonous kinds 

 than they are to the other venomous forms. The non- 



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