1166 REPOET OF NATIONAL MUSEUM, 1898. 



It may readily be distiuguished from G. a. adamanUus by its ligbt color 

 and the truucatious of the rhomboids, as well as the general obsolete- 

 ness of the lateral markings. The rhomboids are longer in proportion 

 and more rounded. The two lateral rows of scales are smooth, the 

 next two more strongly carinated than in C. a. adamanteus. The iifth 

 upper labial is largest, and transverse; the rest nearly uniform. The 

 stripes on the head are less distinct. The last black band on the tail 

 is not so wide, and does not embrace it so as to form a black termina- 

 tion of that organ. The subspecies atrojc has in general the paler 

 characters which western representatives of eastern species so often 

 present, excepting iu regard to the black bands of the tail, which are 

 quite as deep iu color as in the eastern adamanteus. 



As com^jared with the Crotalus confluentus^ which this subspecies 

 resembles at first sight, these color characters always distinguish it. 

 These are in the latter: First, the passage of the dark postocular band 

 above the angle of the mouth ; second, the absence of black rings on 

 ,the tail, and third, the nonrhombic form of the dorsal spots. 



Cat. Nos. Scale. Upper labials. Gastrostegeii. Urosteges. Length. Tail. Kattle. 



inin. mm. mm. 



467 27. 15. 183. 28. 



4225 25. 15. 179. 27. 



12645 27. 16. 182. 18. 



9322 27. 16. 670. 170. 64. 



Four specimens from near Gape St. Lucas, Lower California (Oat. No. 

 12045), all have two loreals as in the subspecies adamanteus. In all 

 other respects these specimens are like the true atro.v, except that in 

 one the posterior canthal plate is smaller than usual, but not so small 

 as in the subspecies ruber. A specimen (Cat. No. 4G7) from the Great 

 Basin has the bleached appearance of the form C. conjiuentus leco7itei, 

 which inhabits the same region. 



This form has the manners of the typical subspecies. I observed a 

 pair of fully grown ones on the headwaters of the Colorado lliver in 

 Borden County, Texas. They were rather sluggish. One I caught in 

 a noose and suspended it on a stick until dead. The other one retreated 

 among the rocks as fast as pursued, and was allowed to escape. 



Crotalus ddamantcus atrox Baird and (Hrard. 



Catalogue 

 No. 



467 



469 

 7760 

 7761 



255 

 4224 

 1801 



273 



263 

 4713 

 4225 



Number 

 of speci- 

 mens. 



Locality. 



Gila and Colorado Kiver. . 



do , 



do 



Indianola, Texas 



do 



.... do 



San Antonio, Texa.s 



Eaglo Pass, New Mexico. 

 San Bois, Choctaw Nation 



Santa Cruz 



Fort Buchanan, Arizona. 

 Kocky Doll Ciock 



1 I Port Yuma, California. 



When 

 collected. 



From whom received. 



Col.J.D. Graham.U.S.A 



do 



do 



L)r. S. W. Woodhouse — 



Lieut. A. W. Whipple, 



U.S.A. 

 Lieutenant Coucli, U.S. A 

 Dr. 15. J. D. Irwin, U.S. A 

 LuMit. A. W. Whipple, 



U.S.A. 

 K, O.Abbott 



Nature of 

 specimen. 



Ale 



oholic. 



do. 



do. 



do. 



do. 



do. 



do. 



do. 



do. 



do. 

 do. 

 do. 



do. 



