14 CROTALUS DURISSUS. 



General Remarks. There can be no doubt that this animal was first made 

 known to naturahsts by Catesby, whose plate of it is too good to be mistaken. 

 Kalm, the celebrated Swedish traveller, next observed it in the northern states of 

 the Union, and gave an accurate scientific description of it, from which Linnaeus 

 extracted the characters that distinguish the Crotalus durissus of the tenth edition 

 of his Systema Naturae. 



Linnffius's account of our Rattlesnake is, however, not clear, for he says it is 

 marked with "maculis rhombois nigris disco albis," while to the South American 

 animal he attributes the habits of tlie durissus, as taken from Kalm: "Vencnatis- 

 smius, antidotum senega; aves sciurosque in faucibus revocat." The only method 

 then remaining to determine to which animal he applied the specific term 

 "durissus," is to consult his references, and then his meaning is clear; for no one 

 doubts that Kalm described our animal, and even Seba's plate is a good one. 



Shaw seems to have confounded this animal with the Crotalus horridus, 

 although the greater part of his description is copied from Catesby, which could 

 only refer to the Crotalus durissus, or Banded Rattlesnake, under which latter 

 name indeed Shaws speaks of it. It is next found mentioned as the Crotalus 

 atricaudatus by Bosc, who supposes it to be a new species, in which he is followed 

 by Latreille and Daudin; but there can be no doubt at present, that they arc one 

 and the same animal, as in the young the tail is generally black, and even in the 

 adult I have seldom seen it otherAvise. 



It is commonly supposed that the number of rattles mark the age of the animal, 

 a new one being added annually to those already existing. It is now' certain that 

 Rattlesnakes have been known to gain more than one rattle in a year, and to lose 

 in proportion; the exact number being regulated no doubt by the state of the 

 animal as to health, nourishment, liberty, &c. I have known two rattles added 

 in one )'ear, and Dr. Bachman has observed four produced in the same length of 

 time. 



