The Rattlesnakes 



The head is grayish above, with a large lyre or U-shaped 

 blotch at the base. From behind the eye to the base of the head, 

 is a broad black band, bordered beneath by white and thus greatly 

 intensified. The abdomen is slaty gray. 



Dimensions. Following are the measurements of an adult 

 specimen, with a rattle composed of six uniform segments. 



Total Length 21 inches. 



Tail, exclusive of rattle i 



Length of Rattle, 6 rings 



Greatest Diameter $ '' 



Width of Head 



Length of Head i| 



Distribution. As the species is very rare the limits of its 

 range are not definitely known. It was discovered in 1895 in 

 the Huachuca Mountains in Arizona, and since that time, barely 

 a dozen specimens have been taken in the United States. The 

 species probably ranges from southern Arizona well into Mexico. 



Through the kindness of Dr. Samuel Carman and Mr. Thomas 

 Barbour, the writer has examined a specimen from the San Bias 

 Mountains, in Chihuahua, Mexico, not far from the boundary. 



Habits. Nothing is known of the habits beyond the dis- 

 position to frequent mountainous places and at a considerable 

 elevation. 



THE WHITE RATTLESNAKE 



Crotalus mitcbellii, (Cope) 



Owing to its pallid colouration, snakes of this species might 

 be confused with pale specimens of the Western diamond rattle- 

 snake, (C. atrox). The similarity, however, is in the whitish 

 colour only. From all the other species of North American 

 Crotalus, the White Rattlesnake differs in an arrangement of 

 the head scales, thus: 



Tbe large plate in front of the nostril (anterior nasal) is sepa- 

 rated from the nose plate (rostral) by small scales. With the other 

 species of Rattlesnakes it will be observed that the shield in 

 front of the nostril is in contact with the nose plate (rostral). 



Colouration. Grayish-yellow or pinkish, the body profusely 

 sprinkled with brown dots. Upon the back these dots are crowded 

 into the form of a series of blotches, which, although not exactly 

 rhomb-like in character, impart much the same effect as the 



463 



