1901.] NATURAL SCIENCES OF PIIILADELPHIA. 107 



Crotalus tigris Kennicott. 



U.S. Mex. Bound. Siirv. Eept., 14, PI. IV (1859); Cope, I. c, 69.3, 

 and Rep. Nat. Mns , 1181 ; Boul., I. c, III, 580 ; Stej., I. c, 449, and 

 No. Am. Fauna, No. 7, 214 ; Van Den., I. c, 220. 



Body ravlier slender; rostral wider than high ; two rows of small 

 plates on the muzzle; about six rows of scales between supraocu- 

 lars; generally two rows between suboculars and labials; scales in 

 21-23 rows (occ. 25); vcntrals 170-181; subcaudals 19-21. 

 Length about 800 mm. 



Grayish or yellowish, witli a dorsal series of ratlier small dark 

 blotches and an indisticct lateral series; on the posterior two-thirds 

 of the body the spots are replaced by cross-bands; belly whitish or 

 yellow; a dark oblique streak behind the eye. 



Hab. — Arizona, southern Nevada and southern California. 



Crotalus lepidus Kennicott. 



Proc. Acad. Phila., 1861, 206; Cope, L c, 692, and Rep. Nat. Mus., 

 1191 ; Boul., I. c, 582 ; Stej., /. c, 452. 



Size small; rostral wider than high; eight J^lates on top of 

 muzzle; 3-4 rows between su])raoculars; 2 between suboculars and 

 labials; one nasal, half divided; the upper preocular divided 

 vertically; scales in 23 rows; ventrals 153-169; subcaudals 27- 

 31. Length 600 mm. 



Greenish gray, with about 20 dark brown or black dorsal spots; 

 tail with several dark half-rings; belly whitish clouded with 

 brown; two lai'ge dark spots in contact on the nape; the dark 

 oblique streak behind the eye is sometimes indicated. 



Hab. — Western Texas to central Arizona; northern Mexico. 



Crotalus cerastes Hallowell. 



Proc. Acad. Phila., 1854, 05 ; Cope, I. c, 694. and Rep. Nat. Mus., 1196 ; 

 Boul., L c. III, 583; Stej., I. c, 450, and No. Am. Fauna, No. 7, 

 216; Van Den., I. c , 222. 



Size small; rostral as wide as high; head scales small, 5-7 be- 

 tween supraoculars; 2 between suboculars and labials; one nasal; 

 supraoculars elevated into a horn-like projection; scales in 21 

 rows; ventrals 134-146; subcaudals 10-21. Length about 

 600 mm. 



Yellowish, with a dorsal series of small brown blotches, and 

 several indistinct series of smaller ones on the sides; belly yellow- 

 ish; a narrow oblique streak behind the eye. 



Hab.— ?Ari zona, southern Nevada, Utah and California. 



