1903.] NATURAL SCIENCES OF PHILADELPHIA. 33 



Death Valley region. The exact relationship and distribution of these 

 two forms and the eastern C. sexlineatus is a very difficult problem, 

 though it would probably be much simplified by adequate material mth 

 exact data, such as that borne by the series before me. Many of the 

 localities quoted by Prof. Cope in his Crocodilians, Lizards and Snakes 

 of N. A. are so exceedingly vague and others so doubtful that they had 

 better be ignored, at least until confirmed. After examining the mate- 

 rial received by him from Texas, it would seem that C. sexlineatus 

 extends over the Austro-riparian region of eastern Texas, departing 

 but little from the normal type until we reach the border of the Lower 

 Sonoran (first plateau) belt. Here we have a form closely resembhng 

 the C. gularis of Dry Canon, which would seem to be the only form in 

 central Texas. C. grahami Cope, of which I have examined speci- 

 mens from the Staked Plains, seems to be most closely related to C. 

 tessellatus; but if the central Texas form is C. gularis, we would have 

 the faunal relation of the representatives of the two species exactly 

 reversed as compared with the vicinity of Alamogordo, since the 

 Staked Plains are Upper Sonoran, and central Texas Lower Sonoran. 

 The Academy has both species from the vicinity of Pecos, but with- 

 out details of distribution; and as both faunal belts occur there in close 

 proximity, it is quite possible that their distribution is as sharply 

 limited as at Alamogordo. Mr. Brown's Pecos collection contains 

 specimens of both tessellatus and gidaris, as well as some identified as 

 sexlineatus. They are accompanied by no data as to relative habitats. 



Cnemidopliorus tessellatus (Say). 



Abundant in the desert about Alamogordo. 

 Pityophis sayi bellona B. and G. 



A number of specimens obtained, which are probably referable to the 

 western desert race. They possess a broad rostral, but have usually a 

 well-indicated black, subcaudal, longitudinal stripe. 



Salvadora grahamise B. and G. 



One specimen obtained which belongs to the typical form. Several 

 others were seen. Mr, Brown obtained one from Pecos, Texas. 



Crotalus adamanteus atrox B. and G. 



One specimen secured. 



Crotalus confluentus Say. 



One specimen which agrees exactly with Prof. Cope's type of C. pul- 

 verulentus from Lake Valley, N. M., but the characters do not seem to 

 have any significance further than indicating individual variation. 

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