14 CROTALUS DURISSUS. 
GeneraL Remarks. ‘There can be no doubt that this animal was first made 
known to naturalists 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 Linneus 
extracted the characters that distinguish the Crotalus durissus of the tenth edition 
of his Systema Nature. 
Linneus’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 the durissus, as taken from IKalm: “Venenatis- 
simus, 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 are one 
and the same animal, as in the young the tail is generally black, and even in the 
adult I have seldom seen it otherwise. 
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 year, and Dr. Bachman has observed four produced in the same length of 
time. 
