4-8. CROTALUS 



212. Crotalus lucasensis Van Denburgh 



San Lucan Diamond Rattlesnake 



Plates 98 and 100 



Caiidisona atrox sonoraensis Cope, Proc. Acad. Nat. Sci. Phila., i86i, 

 p. 292. 



Crotalus adamanteus atrox Cope, Bull. U. S. Nat. Mus., No. i, 1875, 

 p. 33 (part); Yarrow, Bull. U. S. Nat. Mus., No. 24, 1883, p. 75 

 (part); Cope, Proc. U. S. Nat. Mus., Vol. XII, 1889, p. 147; Cope, 

 Proc. U. S. Nat. Mus., Vol. XIV, 1892, p. 691 (part); Cope, Report 

 U. S. Nat. Mus., 1898 (1900), p. 1 164 (part). 



Crotalus atrox Vam Denburgh, Proc. Cal. Acad. Sci., Ser. 2, Vol. 5, 

 1895, p. 156; Nelson, Mem. Nat. Acad. Sci., Vol. XVI, 1921, 

 pp. 1 14, 115; Terron, Mem. y Rev. Soc. Cient. Antonio Alzate, 

 Vol. 39, 1921, pp. 165, 168, 190 (part). 



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

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



.? Crotalus confluentus var. atrox Mocquard, Miss. Sci. au Mexique, 

 Pt. Ill, Rept., 1909, p. 969, pi. 77, figs. 5, 5a (part). 



Crotalus lucasensis Van Denburgh, Proc. Cal. Acad. Sci., Ser. 4, Vol. 

 X, No. 2, 1920, p. 29, pi. 3, fig. I (type locality, Agua Caliente, 

 Cape Region of Lower California, Mexico); Van Denburgh 

 & Slevin, Proc. Cal. Acad. Sci., Ser. 4, Vol. XI, 1921, pp. 52, 70; 

 Nelson, Mem. Nat. Acad. Sci., Vol. XVI, 1921, pp. 114, 115. 



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

 in outline according to position of fangs. Rostral usually 

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

 Usually two preoculars and two to four internasals. A large 

 scale just in front of supraocular. Supraocular large but 

 not raised into a horn -like process} separated from its fellow 

 by from six to eight irregular rows of scales. About 14 to 

 18 superior and 15 to 19 inferior labials; first pair of latter, 

 if not divided, meeting on median line in front of a single 

 pair of genials. About five rows of scales between supra- 

 labials and eye. Scales in about 27 rows, keeled except in 

 one or two rows on each side. Gastrosteges varying from 1 86 

 to 199. Urosteges 17 to 26. 



