NATURAL SCIENCES OF PHILADELPHIA. 207 



specifically different, in which event it may be named C. Sonoraensis. 

 In these specimens the crown presents a decidedly smoother appearance, the 

 plates being less corrugated and lying flat upon the crown without the up- 

 turned edges. They are also smaller, less elongated, and more nearly sub-cir- 

 cular. The stripe from the posterior angle of the orbit reaches the upper 

 labials at a point farther back than it does in the eastern specimens. 



Caudisona scutulata Kennicott. 



Spec. char. Resembles C. 1 u c i f e r in form and coloration of head, and 

 C. a t r o x in coloration of body. Head narrow, nose depressed, rostral tri- 

 angular, as wide as high. Two rather small frontal plates in contact ; 4 post 

 frontals, the external large, overlying the nostril. The space between the 

 superciliaries narrow, filled with large flat plates. Scales on the occiput large 

 and smoother than in C. 1 u c i f e r. Outer dorsal rows of scales less strongly 

 carinated. Rattle remarkably slender. Dorsal rows 25. Labials 16 above, 

 16 below. Three rows of scales between the suborbitals and labials. Light 

 stripe from angle of eye to angle of jaw above the labials, and another from 

 before the eye to the labials, as in C. 1 u c i f e r, but the rostral and space in 

 front of the pit, and nostril not lighter than the crown. On the middle third 

 of the body a dorsal series of distinct rhomboids, margined with whitish and 

 with the lateral angles acute much as in C. a t r o x or C. a d a m a n t e a ; the 

 longitudinal angles sometimes perfect, at others truncate or emarginate. 

 Nineteen brown half rings posteriorly narrow, and separated by wider light in- 

 tervals than in C. lucifer. Rings on the tail narrow, irregular, and quite 

 black. 



This species so closely resembles C. lucifer that a description of it must 

 be comparative to some extent. The head is longer and narrower posteriorly 

 than in C. 1 u c i f e r, and the nose is much more depressed, the rostral being 

 triangular and as wide as high, while in C. 1 u c i f e r it is a third higher than 

 than wide. There are two small sub-triangular or sub-circular frontals in con- 

 tact, and behind these is a row of four scales, the outer and largest one lying 

 directly over the nostril ; posterior to these is a third row of five or six scales, 

 connecting the anterior extremities of the superciliaries, the external scale of 

 which row is a little in advance of the rest ; behind this third row two very 

 large scales connect the superciliaries, behind which the crown is covered 

 with plates much larger than in C. 1 u c i f e r. The space between the super- 

 ciliaries is narrower than in C. lucifer. The rattle is more slender than in 

 any other species excepting C. cerastes. 



The markings on the body of this species are much as in C. a t r o x, and 

 quite unlike those of C lucifer. The ground color is light yellowish or 

 brownish ash ; on the middle third of the body there is a dorsal series of rhom- 

 boidal blotches more or less truncated before and behind ; anteriorly they bo- 

 come elongated longitudinally, and not only truncated but sometimes emargi- 

 nate on the longitudinal angles, while the lateral angles are rounded, leaving 

 the blotches sub-circular. Posteriorly the dorsal blotches continue to have 

 the lateral angles acute and perfect, till they become confluent with a lateral 

 series, and form nineteen half rings, six of which are on the tail. In the mid- 

 dle third of the body the dorsal blotches are included in 11 or 12 dorsal rows 

 and are 4 to 4| scales in longitudinal extent ; anteriorly they become longer 

 longitudinally, and only 9 to 10 scales in transverse diameter. The dorsal 

 blotches are light brown, bordered for the width of one scale with darker. 

 They are separated along the back by a line of the ground color 1^ to 2 scales 

 in width, and immediately bordered by a narrow line lighter than the ground 

 color, as in C. confluentus, atrox and adamanteus, this line being 

 about a half scale in width. Posteriorly the light intervals between the rings 

 widen to 3 or 3j scales, while the rings themselves become much narrower, 

 being only 2 to 3 scales wide. On the middle third of the body below, and op- 



1861.] 



