OPHTDIA. SERPENTIA. 



53 





BAN T DED RATTLESNAKE (Crotalus Horridus). 



a varying number of hollow, horny, or bony cups, 

 each one fitting into the next, where it is loosely 

 held, which at the will of the animal are agitated 

 with a tremulous motion and produce a peculiar 

 rattling sound. It is commonly believed that one 

 of these appendages is added at every moult, and 

 that the age of the Snake may be determined by 

 their number. But it is stated in a paper on the 

 North American Reptilia by Dr. Harlan, published 

 in the Journal of the Academy of Natural Sciences, 

 Philadelphia, that, " the rattle is cast annually, and 

 consequently no inference as to the age of the animal 

 can be drawn from the number of pieces which com- 



