1883.] NATURAL SCIENCES OF PHILADELPHIA. 11 



nostrils above instead of six tubercular ones, and in having the 

 scales of the front flatter. The spots are obscure or entirely 

 wanting ; when present they are more numerous than in the var. 

 maculata^ there being eight between axilla and groin instead of 

 six. The sides and dorso-lateral regions are thickly marked with 

 small yellow spots. Two specimens. 



Cnemidophorus sexlineatus L. 

 Very abundant. 



Stenostoma dulce Bd. and (Jird. 

 One specimen. 



Bascanium testaceum Say. 



Eutaenia cyrtopsis Kena. 



Eutaenia ornata B. and 6. 



Crotalus soutulatus Kenn. Not rare. 



Cro talus confiuentus Say, var. pulverulentus Cope. 



I propose this name for a well-marked variety of rattlesnake, 

 which is abundant in the region of Lake Valley, especially on the 

 grassy plains. In order to determine its relations to the species 

 to which I refer it, I instituted a comparison with the allied forms 

 represented in my collection. These are : Two specimens from 

 Fort Benton, Montana ; two from Central Oregon ; two from 

 Eastern California ; one from Socorro, New Mexico ; one fi'om 

 Fort Wingate, New Mexico ; two from Lake Valley, New Mexico, 

 and one from Haskell County, Texas. These represent a wide 

 range in latitude, and are likely to give the greatest range of 

 variation. The comparison indicates three varieties, defined as 

 follows : — 



Cephalic scales larger ; four rows between superciliary plates ; 

 four rows below orbit; dorsal spots and cephalic bands light- 

 edged ; few posterior cross-bands ; confiuentus. 



Cephalic scales intermediate ; six rows between superciliaries ; 

 three rows below orbit (probably sometimes four) ; dorsal spots 

 square, with the head-bands, not light-edged; posterior cross-bands 

 more numerous ; colors dotted with brown specks; pulverulentus^ 



Cephalic scales smallest; eight rows between superciliaries; four 

 rows below orbit ; dorsal spots and head-bands light-edged or not ; 

 numerous posterior cross-bands ; lucifer. 



The var. pulverulentus^ at first sight, resembles the Ci'otalus 

 mitchilli, having much the same coloration, but the head-scales and 



