860 13. COLURRID.% 



Sonora occipitalis VAN DENBURGH & SLEVIN, Proc. Cal. Acad. Sci., 

 Ser. 4, Vol. 3, 1913, p. 412; CAMP, Univ. Cal. Publ. Zool., Vol. 12, 

 No. 17, p. 531; GRINNELL & CAMP, Univ. Cal. Publ. Zool., Vol. 

 17, No. 10, 1917, p. 182; STEJNEGER & BARBOUR, Check List N. 

 Amer. Kept., 1917, p. 92; STEPHENS, Copeia, No. 54, 1918, p. 34; 

 COWLES, Journ. Entomol. & Zool., Pomona College, Vol. XII, 

 No. 3, 1920, p. 65; STEPHENS, Trans. San Diego Soc. Hist., Vol. 

 Ill, No. 4, 1921, p. 64; VAN DENBURGH & SLEVIN, Proc. Cal. Acad. 

 Sci., Ser. 4, Vol. XI, 1921, p. 52. 



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 1 5 1 , to 1 74. 

 Urosteges in two series of from 34 to 53. 



In alcoholic specimens, the ground color is 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 



