332 BANDED RATTLE-SNAKH. 



observes that it consists of hollow, hard, dry, and 

 semitransparent bones, nearly of the same size 

 and figure ; resembling in some degree the shape 

 of the human os sacrum ; for although only the 

 last or terminal one seems to have a rigid epiphysis 

 joined to it, yet have every one of them the like ; 

 so that the tip of every uppermost bone runs 

 within two of the bones below it ; by which ar- 

 tifice they have not only a moveable coherence, 

 but also make a more multiplied sound : each 

 bone hitting against two others at the same time. 



The rattle is placed with the broad part perpen- 

 dicular to the body, and not horizontal ; and the 

 first joint is fastened to the last vertebra of the tail 

 by means of a thick muscle under it, as well as 

 by the membranes which unite it to the skin : all 

 the remaining joints are so many extraneous 

 bodies, as it were, or perfectly unconnected to the 

 tail by any other means than their curious inser- 

 tions into each other. 



The number of joints in the rattle of different 

 individuals is very various, from five to twelve, 

 fifteen, twenty, or even, according to some ac- 

 counts, as many as forty. The pieces of which it 

 consists are successively formed, each having 

 been once attached to the muscle of the last ver- 

 tebra of the tail, and driven on b}^ the gradual for- 

 mation of a young or immature one beneath it ; 

 but as it is not known whether these successive 

 formations of new joints in the rattle correspond 

 with the general changes of the skin, and as the 



