18 UNITED STATES AND MEXICAN BOUNDARY. 



rest with keels extending to their tips. Scales broader than in preceding. Disproportion between scales 

 of the back, before and behind, not conspicuous. Light chestnut, with 20 yellow blotches from head to 

 anus, and 9 on the tail. Beneath yellow. 



1271. Indianola. J. H. Clark. 



81. HETERODOX NASICUS, B. & G. 



Plate XI, Fig. 1. 



Heterodon nasicus, B. & G. Stansbury's Kep. Great Salt Lake, 1852, 352. — Ib. Catal. Serp. 



1853, 61. 



Sp. Ch. — Vertical broader than long. Eostral excessively broad and high. Azygos plate surrounded 

 behind and on the sides by many small plates (12-15.) Sometimes a second loral. Labials short and 

 excessively high. Dorsal rows of scales 23, exterior alone smooth. A dorsal series of about 50 blotches, 

 with four or five others on each side. Body beneath black. A narrow white line across the middle of 

 the superciliaries; a second behind the rostral. A broad dark patch from the eye to the angle of the 

 mouth, crossing the last two labials. 



Fort Webster, and 1260, Sonora. J. H. Clark.— 1249. Eagle Pass. A. Schott,— 1262. 

 Copper Mines. J. H. Clark. 



82. P1TYOPHIS BELLONA, B. & G. 



Churchillia bellona, B. & G. Stansbury's Report, 1852, 350. 

 Pituophis bellona, B. & G. Catal. N. Am. Serp. Jan. 1853, 66. 

 Pituophis affinis, Hallowell, Pr. A. N. Sc. VI, 1852, 181. 



S P# Ch. — Head broad behind, tapering to the snout. Snout rather pointed, but less so than P. sayi ; 

 elevated. Crown flattened between the eyes and posteriorly. Vertical plate broad anteriorly; elongated 

 and narrow posteriorly. Ante-orbitals two, sometimes one. Post-orbitals three or four. Frequently a supple- 

 mental plate before the vertical. Dorsal rows of scales 29 to 35, the seven outer rows smooth. Head spotted 

 with black; transverse frontal bar extending from one orbit to the other, well marked; the oblique 

 post-ocular vitta rather narrow. Color of the body whitish yellow. A dorsal series of 45 to 65 

 sub-quadrate blotches from head to anus, transversely elongated posteriorly; three or four smaller series 

 on each side. The lateral blotches are longitudinally elongated near the head, and vertically elongated 

 posteriorly where they form a series of jet black vertical bands. There are 10 or 15 black bands on the 

 tail. Abdomen yellow, with an external series of black spots on each side. — (Kennicott.) 



1542. 1543. Through Texas. J. H. Clark. — 1546. San Bernardino to Kio San Pedro, 

 Mexico. Dr. C. B. Kennerly. 



83. ARIZONA 1 ELEGANS, Kennicott. 



Plate XIII. 



Sp. Ch. — Body rather more slender than in Pityophis sayi and P. bellona, and head narrower; otherwise 

 bearing a general resemblance in form to these and other species of Pityophis, especially in the protruding 



1 Genus Arizona, Kennicott. — Size large. Body sub-cylindrical, deeper than wide. Head ovoid 

 rather narrow. Snout obtusely pointed, projecting beyond the lower jaw. Eye small. Cleft of mouth 

 curved. Cephalic plates normal. Pre-frontals elongated longitudinally; post-frontals elongated trans- 

 versely. Pre-frontals extending down in front of nostrils. Rostral large, and protruding apex turned 

 back between pre-frontals. Nostril between two plates; anterior smallest. A narrow loral as long as 

 the post-frontals. One or two pre-orbitals, two post-orbitals. Dorsal scales all perfectly smooth, in about 

 29 to 31 rows. Post-abdominal scutella entire; sub-caudal all biped. 



In its general aspect this genus somewhat resembles Pityophis, from which it differs widely, however, 

 in its single pair of post-frontals, smooth scales, and different nasals, loral, pre-frontals, &c. — (Kennicott.) 



K 



