OPH1DIA—CEOTALIDAE— CAUDISONA ADAMANTEA. 607 



rant varietal distinction of this southern form, which may be called C. luci- 

 fer var. cerberus. 



Nos. 509, 511, and others, rny collection, from the San Francisco 

 Mountains, July, 1864. 



This species was found associated with C. confluenta in Northern and 

 Central Arizona, where it is abundant. The great size to which it attains, 

 the caliber of the body, and black color combine to render it peculiarly 

 repulsive. An unusual degree of virulence is attributed by backwoodsmen 

 to the "Black Rattlesnake", but probably without foundation. 



43. Caudisona adamantea atrox (Bd. & Gir). 



Crotalus atrox, Bd. & Gir.. Cat. N. A. Eept., 1853, 5, 15C— Bd., P. E. B. Bep., x, 

 1859, Whipple's Eoute, Reptiles, 39, pi. 24, f. 3.— Id., U. S. & Mex. Bound. 

 Surv., ii, pt. ii, 1859, Beptiles, 14, pi, 1. 



Caudisona atrox, Cope, Mitchell's Ees., 18G1, 121. — Cope, Proc. Acad. Nat. Sci. Phila., 

 1SG6, 309. 



Crotalus adamanteus, subsp. atrox, Cope, Check-List, 1875, 33. 



Head subtriangular. Plates on head; 2 anterior frontals in con- 

 tact; between these and superciliaries, on side of crown, 2 imbricated 

 plates ; space inclosed occupied by smaller scales ; superciliaries bordered 

 by a row of larger scales ; the anterior much largest, Three rows of scales 

 between labials and suborbitals. Labials 16 above, first, fifth, and seventh 

 largest ; 15 below, first and third largest ; dorsal rows 25-27 ; 2 exterior 

 rows smooth. On the tail 3-6 half-rings. Color yellowish-brown, with a 

 continuous succession of dorsal lozenges, sometimes truncate before and 

 behind ; intervals all narrow. A single transverse light line on superciliary. 

 Stripe from superciliary directly to angle of mouth. — {B. <& G., descr. orig.) 

 Rattle and rostral plates as in C. lucifer. 



Originally described only from Texas, and quoted with this restriction 

 by Professor Cope in 1861 (7. a). This species was ascertained by the Mex- 

 ican Boundary Survey, results of which were published in 1859, to occur 

 also in the lower portions of Arizona, 



43«. Caudisona adamantea scutulata, (Kenn.). 



Caudisona scutulata, Kexn., Proc. Acad. Nat. Sci. Phila., 1861, 207. — Cope, Proc. 



Acad. Nat. Sci. Phila., 1S66, 307. 309. 

 Crotalus adamanteus, subsp. scutulatus, Cope, Check-List, 1875, 33. 



