266 ZOOLOGY. 



large behind, with a flat crown, which is covered by scales (except in one 

 or two genera, which have plates). The belly is covered by broad band- 

 like shields, and there are no spurs or rudimentary feet on each side of the 

 anus. The species are all more or less venomous, and generally ovo- 

 vivi parous. 



The genus Crotalus, or rattlesnake, forms the type of this family, and 

 its species are distinguished from all the rest by the presence of a rattle at 

 the end of the tail. This consists of several joints of a horny texture 

 loosely united together, so that when quickly vibrated a noise is produced 

 much like that of peas shaken about in a dried bladder, and bearing a 

 considerable resemblance to the sound produced by the locust or cicada. 

 There are two or three species of the restricted genus Crotalus in North 

 America : one the C durissus, another the C. adamanteus. The former 

 is abundantly distributed throughout the United States, although limited 

 in northern extent, and rarely found north of the parallel of 45° ; it is espe- 

 cially common in the Alleghany region of the United States, where its 

 habits are familiar to every resident. It is a sluggish animal, and not 

 disposed to act on the oflfensive, so that a person may pass within a few 

 feet of it without being molested. An approximation of that kind is 

 generally followed by an alarm from the snake, which most usually pre- 

 cedes any blow. The animal never strikes except when coiled, and rarely, 

 if ever, follows a retreating enemy. Its food consists of small anin)als, 

 rabbits, squirrels, rats, birds, &c., all of which are speedily destroyed by a 

 single blow. Even dogs are sometimes killed by them, although larger 

 animals are not generally destroyed. The immense Crotalus adamanteus, 

 or diamond rattlesnake of the Southern States, is vastly more formidable. 

 This species appears restricted to the southern coast below the latitude of 

 North Carolina, and has been known to exceed eight feet in length, with a 

 thickness equal to that of a stout man's leg. They keep much about the 

 water, and have hence been called the water-rattle, in distinction from the 

 preceding species, which affects high dry land. A third species, common 

 in South America, is C. horridus, sometimes called Cascavella, and repre- 

 sented in pi. 87, fig. 5. There are also several small species in North 

 America belonging to an allied genus Crotalojihorus, and usually termed 

 ground rattlesnakes. These have the head covered with plates, and the 

 rattles very small, even in individuals of considerable size. One of the 

 species, called the Massasauga, occurs in Northern Ohio, others in the 

 Southern States, and in the region west of the Mississippi. 



The copperheads (genus Trigonocephalus) of America are, if possible, 

 more dreaded than even the rattlesnakes, owing to the fact that, with equal 

 venom, they are more vindictive and give no warning of their presence. 

 The most generally distributed species, T. contorlrix, is fond of damp 

 meadows, where it is often revealed to the cost of persons engaged in 

 mowing or passing through. They not unfrequently get into cellars, 

 where they perform an acceptable service in destroying mice and rats. 

 The water-moccasin of the Southern States (T. piscivorus) is the pest of 

 rice plantations, where negroes are often bitten. This species lives in the 

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