860 13. COLUBRIDA 
Sonora occipitalis Van DenspurcH & Stevin, Proc. Cal. Acad. Sci., 
Ser. 4, Vol. 3, 1913, p- 412; Camp, Univ. Cal. Publ. Zool., Vol. 12, 
No. 17, p. 531; GRrinneLL & Camp, Univ. Cal. Publ. Zool., Vol. 
7, No. 10, 1917, p. 182; SreyNEGER & Bargour, Check List N. 
Amer. Rept., 1917, p. 92; STEPHENS, Copeia, No. 54, 1918, p. 343 
Cow es, Journ. Entomol. & Zool., Pomona College, Vol. XII, 
No. 3, 1920, p. 65; STEPHENS, Trans. San Diego Soc. Hist., Vol. 
III, No. 4, 1921, p. 64; Van Densurcu & SteEvin, Proc. Cal. Acad. 
Scis, cer. 45 Vol, oeljirg2T ip. 62. 
Description—Head but little wider than neck, de- 
pressed, temporal regions not much swollen. Snout rather 
broad, greatly depressed, pointed in profile, produced far 
beyond lower jaw. Rostral large, broad, low, projecting 
far beyond mental, very concave below, considerably re- 
curved on top of snout, and bounded behind by internasal, 
nasal, and first labial plates. Plates on top of head are a 
pair of internasals, a pair of prefrontals, a frontal, supra- 
ocular of each side, and a pair of parietals. Anterior and 
posterior nasals united into a single plate. Loreal usually 
elongate, often quite small, very rarely absent. One pre- 
ocular. Two postoculars. Temporals one followed by two. 
Supralabials usually seven, rarely six, third and fourth reach- 
ing eye, fourth or sixth largest. Infralabials usually eight, 
sometimes seven, fourth largest, first pair meeting on median 
line. Genials in two pairs, the posterior much smaller. 
Scales on body smooth, polished, in 15 rows. Anal plate 
divided. Gastrosteges varying in number from 151, to 174. 
Urosteges in two series of from 34 to 53. 
In alcoholic specimens, the ground color 1s white, or 
grayish white. On the head is a more or less crescentic dark 
brown or black blotch the central portion of which occupies 
part or all of the parietal plates, and often a portion (none 
to three-fourths) of the frontal, while the extremities ex- 
tend to the eyes. On the body between the head and the 
