CROTALUSDURISSUS. 85 



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 

 Shaw 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. 



Mr. Peale of the Philadelphia Museum, kept a living female rattlesnake for 

 fourteen years. It had when it came into his possession eleven rattles, several 

 were lost annually and new ones took their place; at its death, after fourteen 

 years confinement, there were still but eleven joints, although it had increased 

 four inches in length. It is thus evident that the growth of their appendages is 

 irregular, and that the age of the animal cannot be determined from their number. 

 The number of rattles vaiy much; the largest I ever saw was twenty-one, all of 

 which were perfect. 



