122 REPTILES AND BATRACHIANS 



Crotalus confluentus Say, 1823. 



In complete rattles the taper portion includes no more 

 than seven rings, and the average size of snakes reaching 

 this number is less than three feet, showing the species to 

 be smaller than the preceding. A fourteen-inch specimen 

 has one ring and the button ; a twenty-three inch, taken 

 up in the mountains, has seven rattles, of which three 

 show comparatively little taper, possibly evidence of short 

 allowances. Fourteen specimens. 



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 Crotalus horridus Linn., 1758. 



The pronounced taper appears to include the eighth ring 

 in a couple of cases. On very large specimens with long 

 series of rings it is quite evident there is taper in what 

 from a small number of the rings would be called paral- 

 lel ; this is seen plainly on measuring rings at a distance 

 from each other. Individuals with complete series of seven 

 rings all tapering measure from two feet eight inches to 

 three feet three inches. One, two feet ten inches long, hav- 

 ing lost some rings, still has five of the taper and five of the 

 parallel. Another, four feet four inches in length, has lost 

 all but seven of the parallels. The first ring and the button 

 appear on one of nineteen inches. Eighteen specimens. 



Crotalus adamanteus Beauv., 1799. 



The largest on which we find all the rings taper is three 

 feet seven and a half inches in length. On one of three 

 feet four inches and another of four feet eleven inches the 

 rings form parallels. Four specimens, rattles incomplete. 



Crotalus durissus Linn., 1758. 



A seventeen inch specimen has not yet grown a ring ; 

 a three feet nine inch has nine rings and the button, seven 

 tapering, the seventh to the button parallel ; a four feet one 

 inch has seven rings and a button, the taper apparently 



