920 16. CROTALIDM 



Ser. 1, Vol. 5, 1895, p. 157; VAN DENBURGH & SLEVIN, Proc. Cal- 

 Acad. Sci., Ser. 4, Vol. 4, 1914, pp. 133, 145; GRINNELL & CAMP> 

 Univ. Cal. Publ. Zool., Vol. 17, No. 10, 1917, p. 196; STEJNEGER 

 & HARBOUR, Check List N. Amer. Amph. Kept., 1917, p. 109; 

 STEPHENS, Trans. San Diego Soc. Nat. Hist., Vol. Ill, No. 4, 1921, 

 p. 65; VAN DENBURGH & SLEVIN, Proc. Cal. Acad. Sci., Ser. 4, 

 Vol. XI, 1921, pp. 52, 71; NELSON, Mem. Nat. Acad. Sci., Vol. 

 XVI, 1921, p. 114. 



Crotalus adamanteus ruber COPE, Proc. U. S. Nat. Mus., Vol. XIV, 

 1892, p. 690 (type locality, unknown). 



Crotalui atrox ruber STEJNEGER, Report U. S. Nat. Mus. for 1893, 1895, 

 p. 439; BROWN, Proc. Acad. Nat. Sci. Phila., 1901, p. 104; DIT- 

 MARS, Reptile Book, 1907, p. 455, pi. CXXXII, fig. 2; RITTER, 

 Copeia, 1921, No. 94, p. 29. 



Crotalus confluentus BOULENGER, Cat. Snakes Brit. Mus. Vol. Ill, 1896, 

 p. 576 (part); MOCQUARD, Nouv. Arch. Mus. Hist. Nat., Ser. 4, 

 Vol. I, 1899, p. 332. 



Crotalus ruber VAN DENBURGH, Proc. Cal. Acad. Sci., Ser. 2, Vol. 5, 

 1895, p. 1007; VAN DENBURGH, Occas. Papers Cal. Acad. Sci., 

 Vol. V, 1897, p. 226; COPE, Report U. S. Nat. Mus. for 1898, 1900, 

 p. 1167, fig. 335; MEEK, Field Columbian Mus., Zool. Ser., Vol. 

 VII, No. i, 1906, p. 17; ATSATT, Univ. Cal. Publ. Zool., Vol. 12, 

 No. 3, 1913, p. 44- 



? Crotalus confluentus MOCQUARD, Nouv. Arch. Mus. Hist. Nat., Paris, 

 Ser. 4, Vol. I, 1899, p. 332. 



? Crottlis confluentus var. atrox MOCQUARD, Miss. Sci. au Mexique, 

 Pt. Ill, Rept., 1909, p. 969, pi. 77, figs, s, S*- 



Crotalus atrox TOWNSEND, Bull. Amer. Mus. Nat. Hist., Vol. XXXV, 

 1916, p. 426. 



Description. Large. Head broad, flat-topped, varying 

 in outline according to position of fangs, etc. Rostral usually 

 higher than wide, in contact with anterior nasal. Two nasals. 

 Usually two preoculars, three postoculars, and two to four 

 internasals. A large scale just in front of supraocular. Supra- 

 ocular large but not raised into a horn-like process} separated 

 from its fellow by six or seven irregular rows of scales. 

 About 13 to 18 superior and 14 to 19 inferior labials; first 

 pair of latter usually divided transversely, in which case the 



