180 [October, 



men silvery white, with two longitudinal blue colored blotches having two ob- 

 lique bars of black running across them ; two small blue spots upon the under 

 surface of tail. 



Dimensions. Length of head 7^ lines ; length of neck and body to anus 2 

 inches 2^ lines; of tail in the specimen examined, which appears to have been 

 mutilated and restored, 2 inches 3 lines ; body 1 inch 5 lines in circumference ; 

 length of arm 6 lines ; of fore arm 5^ lines ; of hand to extremity of longest 

 nail 7| lines ; of feet to extremity of longest toe 1 inch 2 lines j total length of 

 body 5 inches 1 line. 



Habitat. New Mexico. 



Remarks. This animal approaches Crotaphytus, Holbrook, but the nostrils 

 are superior instead of being lateral as in the latter genus. The head of Crota- 

 phytus is covered with tubercles, and the occipital plate does not exist, or is 

 small and ill-defined. The forearm is also shorter and much more robust, 

 and the longest fingers are of nearly equal length ; in Homalosaurus the 

 fourth finger is considerably longer than the third. The temples are much 

 less swollen than in Crotaphytus, which has but a single row of plates along ihe 

 border of the lower jaw. The nostrils in Holbrookia are situated as in Homa- 

 losaurus ; and the plates along the margin of both the upper and under jaw 

 have the same configuration and arrangement ; the occipital plate also is 

 very distinct, which, as well as most of the plates upon the upper part of the 

 head, is smooth ; a considerable number of granulations, however, are observed 

 above the supraciliary ridge at its anterior and posterior part, chiefly in the 

 former position ; but in Holbrookia there are no external ears, the ear lying im- 

 mediately beneath the skin, which covers it. Both Holbrookia and Crotaphytus 

 have femoral pores, bat no anal ones, of which also Crotaphytus is destitute. 



Crotalus Lecontei. 



Sp. Char. Head quadrangular, broader behind than in front, much flattened 

 above ; a few small plates in front : the rest of the upper surface of the head, 

 except over the orbit, covered with scales ; a series of about thirty subquad- 

 rate brownish blotches along the back, and ten or twelve transverse bands of 

 the same color ; brownish bands upon the tail ; subquadrate blotches along the 

 back, margined with light yellow ; ground color light yellow or straw-color ; 

 scales strongly carinated ; abdominal scuta 174 ; sub-caudal 27. 



.Dimensions. Length of head 14 lines ; greatest breadth 11 lines; length of 

 body 2 ft. 9 in. 9 lines ; length of tail, exclusive of rattles, 2 inches 6 lines ; 

 length 2 ft. 6 inches 5 lines. 



Habitat. Cross Timbers. 



Remarks. My friend Dr. Le Conte informs me that he found near the 

 Colorado, about seven hundred miles from the last mentioned locality, a species 

 of Crotalus which was very abundant in that region, over four feet in length, 

 and which appears to be the same as the one above described. He took the 

 following notes of it upon the spot: ** Crotalus cinereous ; black with a series 

 of subrhomboidal spots margined with dark brown, and exterior to this a line 

 of white scales ; sides with a few darker cinereous spots; beneath pale ochra- 

 ceous ; neck and under part of head white ; tail white, with four black rings,* 

 becoming irregular beneath. Length 4^- feet ; greatest circumference 5 J inches ; 

 185 transverse scales beneath the body, 28 caudal; fourteen scales in tbe ob- 

 lique rows from spine to side in middle and on neck ; nine posteriorly and on 

 tail. Colorado, March, 1851." The dorsal spots become indistinct behind. 

 Sandy deserts. 



5^ In a young specimen brought by Dr. Woodhouse these four black rings are 

 very distinct. 



