FROM TEXAS AND MEXICO. 123 



extending to the eighth ring ; and a four feet six inch 

 has eleven rings and a button, seven rings in the tapering 

 portion. 



Crotalus lucifer B. & G., 1852. 



On a two feet eight inch individual there are five rings 

 in the parallel and three in the taper part of the broken 

 rattle. 

 Crotalus exsul Garm., 1883. 



A twenty-two inch specimen has eight rings tapering 

 and from the eighth to the twelfth in the parallel. In this 

 case the first was nearly as large as the sixth and the ta- 

 per is comparatively slight. 



8istruru8 catenates Raf. ; Garm. Massasauga. 



Young, at birth, measure eight and a half inches. Fe- 

 males reach the seventh ring, or finish the tapering part 

 of the rattle, and become " full grown," at a trille more 

 than two feet in length, the males at less. A two feet ten 

 inch specimen appears to have reached full size with the 

 sixth ring; the sixth, seventh and eighth showing no taper. 

 Thirteen specimens. 



Sistrurus miliarias Linn. ; Garm. Ground Rattler. 



A young one, how long at birth not known, with only 

 a button, measures six and a half inches. The average 

 size of full grown is rather less than seventeen inches. 

 Sexual maturity is sometimes reached before the tapering 

 series is completed. A gravid female with three equal 

 rings and a button had a length of only sixteen inches. 

 Twelve specimens. 



Crotalus molossus B. & G., 1853. 



From the mountains of Alvarez, near San Luis Potosi, 

 Mex. 



