160 CALIFORNIA ACADEMY OF SCIENCES. 



tapering tail, and little if any constriction at neck. 

 The snout is long, rounded, and much depressed. The 

 head-plates are normal except in the union of the an- 

 terior and posterior nasals. One preocular, two post- 

 oculars, and a loreal are present. Temporals are normally 

 1-2. The scales are smooth, in fifteen rows. The anal 

 plate is divided and the urosteges are in two series. The 

 eye is rather small, with round pupil. 



48. Chionactis occipitalis (Hallowell). DESERT SNAKE. 



Rhinostoma occipitale, HALLOW., Proc. Ac. Nat. Sci. Phil., VII, 1854, 



p. 95 (type locality Mojave Desert). 

 Lamprosoma occipitale, HALLOW., 1. c., VIII, 1856, p. 310; HALLOW., 



U. S.Pac.E. E. Surv., X, 1859, pt.IV, p. 15, pi. IV, figs. 2a-2c; 



KENN., U. S. Mex. Bound. Surv., Ill, Eept., 1859, p. 21, pi. XXI, 



fig. 1; BOCOURT, Miss. Sci.au Mex., Eept., 9eLivr., 1883, p. 558, 



pi. XXXIV, fig. 6-6e. 

 Lamprosoma annulatum, BAIRD, U.S. Mex. Bound. Surv., Ill, Eept., 



1859, p. 22, pi. XXI, fig. 1 (type locality Colorado Desert). 

 Chionactis occipitalis, COPE, Proc. Ac. Nat. Sci. Phil., 1866, p. 310; 



COPE, Proc. U. S. Nat. Mus., XIV, 1891, p. 605. 

 Contia occipitalis, GARMAN, Mein. Mus. Compr. Zool., VIII, 3, 1883, 



p. 91; BOULENGER, Cat. Snakes Brit. Mus., II, 1894, p. 266. 



Description. "Head small, of same breadth poste- 

 riorly as neck, depressed in front; snout rounded; rostral 



plate large, excavated 

 below, presenting a tri- 

 angular shape above and 

 in front where it forms 

 the extremity, of the 

 muzzle ; internasals 



smaller than prefrontals, their inner margins much 

 shorter than their external, which are in contact 

 with the upper margins of the nasal plates; the pre- 

 frontals are more or less pentangular in shape, the 

 posterior margin of each in contact with the ante- 

 rior margin of the antocular, the supraocular, and 



