OPHIDIA. 



63. CROTALUS ATROX, B. & G 



Plate I. 



Crotalus atrox, B. & G. Catal. N. A. Serpents, Jan. 1853, 5. 



Nos. 258, 256, 4226, 271. Throughout Texas. Schott, Clarke, Kennerly 

 Nos. 466, 467, 468. Bottoms of Gila and Colorado. A. Schott. 



64. CROTALUS CONFLUENTUS, Say. 



Crotalus conjluentus, Say. Long's Exped. II, 1823, 48. — B. & G. Catal. N. A. Serpents, Jan 



1853, 8. 



No. 4228. Between San Antonio and El Paso. J. H. Clark. — No. 4247. Cimeron. J. 



H. Clark. 



65. CROTALUS MOLOSSUS, B. & G. 



Plate II. 



Crotalus molossus, B. & G. Catal. N. Am. Serp. Jan. 1853, 10. 

 Crotalus ornatus, Hallow. Pr. A. N. Sc. VII, Oct. 1854, 192. 



No. 485. Fort Webster. Copper Mines, N. M. J. H. Clark. 



66. CROTALUS TIGRIS, Kennicott 



Plate IV. 



Sp. Ch. 



very 



frontals 



suborbital 



obtuse; whole outline of head nearly quadrangular. Superciliaries an<3 



superciliaries very wide; four frontal plates, six post-frontals. Two ro 



chain (which is complete) and the labials. Labials 14 above, 13-14 below. Dorsal rows 21-23; very 



slightly carinated. Dorsal scales broad, rounded behind. Color yellowish ash above, with rather small 



indistinct dorsal brown blotches anteriorly; two posterior thirds of body banded with brown. — (Kennicott.) 



Deserts of Gila and Colorado. 



No. 471. Sierra Yerde and Pozo Verde. A. Schott. • 



67. CROTALUS CERASTES, Ha Howe 11. 





Plate III. 



Crotalus cerastes, Hallowell, Pr. A. N. Sc, June, 1854, 95. 



Sp. Ch. — Head small, angles rounded; nose obtuse, much depressed; rostral as broad as high; nostril 

 *n the middle of a single large plate. Lateral edge of superciliary plate elongated into a horn-like 

 process directed upward over the eye. Two rows of scales between the sub-orbital series (which is 









