1178 REPORT OF NATIONAL MUSEUM, 1898. 



The theory of coloration is that of decussating lines, which, when 

 they intersect, unite so as to have the angles of intersection truncated. 



The species has a general resemblance to G. a. atrox in the arrange 

 nieut of the blotches, but is darker, and has about seventeen dark 

 half rings posteriorly instead of four or five. In G. a. atrox the head 

 is narrower and more triangular, the s])ace between the superciliaries 

 narrow, and occupied by augulated larger scales instead of small tuber- 

 culous ones. In G. a. atrox the row bordering the superciliaries is much 

 larger than the rest, and the scales on the top of the head generally more 

 angulated. In C. c. Incifer the line on the side of the head, instead of 

 going directly from the posterior end of the superciliary to the commis- 

 sures, passes back nearly parallel to the moutli, crossing along the fourth 

 row of scales above the labial. The second line in front of the eye is 

 much wider below in G. c. lucifer, and the face generally shows more of 

 white, while the dark portions are mu<-h darker. 



In small specimens the colors are much brighter and the pattern 

 better defined. Such individuals graduate into the G. c. conjiiientus of 

 corresponding age which are found in southern California. On the 

 other hand, the large sjjecimens become obscure in the pattern of col- 

 oration, and lose various marks; for instance, the superior border of 

 the postocular band and the lateral borders of the dorsal spots. This 

 form is simply the dark-colored phase of G. conjiiientus, characteristic 

 of a relatively wet climate. 



As already remarked, this subspecies is directly connected with the 

 typical one G. c. confluentus by the intermediate form G. c. lecontei. 

 This gradation is especially evident in specimens from the mountains 

 of Arizona, where the colors are apt to be dark; as for instance in speci- 

 men, Cat. No. 8397. 



Cat. Nos. Scales. Upper Gastrostege.s. Urostegea. Length. Tail. Rattle. 



labials. " mm. mm. mm. 



4254 -.. 25. 15. 169. 26. 1,034. 142. 65. 



373 25. 15. 157. 23. 



8397 23. 16-17. 177. 23. 



7762 25. 16. 168. 25. 



Dr. Stejneger, in his report upon the rei)tiles of the Death Valley 

 Expedition, says: 



The present species is characteristic of the interior valley and slopes of California 

 as contrasted with the Great Basin, and the boundary between the two forms seems 

 to be quite sharply drawn, at least in the regions visited by the expedition. There 

 is probably no stronger contrast among the reptiles of the same genus met with by 

 theUeath Valley explorers than that between the pale and clay-colored rattlesnakes 

 in the desert plains [C. c. lecontei E. D. C] and mountains, and the dark-colored C. 

 lucifcr which they obtained only in the San .Joaquin Valley and in the monntain 

 slopes encircling it. 



The distribution of this subspecies is given by Dr. C. Hart Merriam 

 in the same publication, as follows: 



This species does not inhabit the Great Basin, but was found in a number of locali- 

 ties on the west or costal slope of the Sierra, and in the San Joaquin Valley. Speci- 



