41. SONORA 859 
a.—Snout less depressed, rounded in profile; rostral plate 
projecting less beyond lower jaw. 
b.—Back with a series of transverse or dark brown bars. 
S. semiannulata.—p. 863. 
b.—No transverse dark bars; sides with longitudinal 
lines made up of dark dashes on the centers of the 
scales. 
S. episcopa.—p. 866. 
194. Sonora occipitalis (Hallowell) 
Tricotor GrounD SNAKE 
Plate 95 
Rhinostoma occipitale HavttoweE.L, Proc. Acad. Nat. Sci. Phila., Vol. 
VII, 1854, p. 95 (type locality, Mojave Desert). 
Lamprosoma occipitale HaLtowE.1, Proc. Acad. Nat. Sci. Phila., 1856, 
p. 110; Barrp, U. S. Mex. Bound. Surv., Vol. H, 1859, Rept., 
p. 21, pl. 21, fig. 1; Barrp, Rep. Pac. R. R. Surv., Vol. X, Pt. IIT, 
1859, p. 16, pl. XXXV, figs. 6, 7; HattoweLt, Rep. Pac. R. R. 
Surv., Vol. X, Pt. IV, No. 1, 1859, p. 15, pl. IV, figs. 2a-c; Bo- 
court, Miss. Sci. au Mex., Rept., 1883, p. 558, pl. XXXIV, fig. 6. 
Lamprosoma annulatum Bairp, U.S. Mex. Bound. Surv., Vol. II, 1859, 
Rept., p. 22 (type locality, Colorado Desert). 
Chionactis occipitalis Corre, Proc. Acad. Nat. Sci. Phila., 1860, p. 241; 
Cooper, Proc. Cal. Acad. Sci., Vol. XIV, 1870, p. 66; Cope, Bull. 
U.S. Nat. Mus., No. 1, 1875, p. 35; YARRow, Bull. U.S. Nat. Mus., 
No. 24, 1883, p. 86; Cope, Proc. U. S. Nat. Mus., Vol. XIV, 1892, 
p- 605; Van Densurcu, Occas. Papers Cal. Acad. Sci., V, 1897, 
p. 160; Corr, Report U. S. Nat. Mus., for 1898, 1900, p. 941; 
Meek, Field Columbian Mus., Zool. Ser., Vol. VII, No. 1, 1906, 
p- 15; RicHarpson, Science, N. S., Vol. XXXII, No. 820, 1910, 
p- 383. 
Chionactis occipitalis annulata Corr, Bull. U. S. Nat. Mus., No. 1, 
1875, p. 36; YARRow, Bull. U. S. Nat. Mus., No. 24, 1883, p. 86. 
Contia occipitalis Garman, Mem. Mus. Compr. Zool., Cambr., Vol. 
VIII, No. 3, 1883, pp. 91, 164; Boutencer, Cat. Snakes Brit. 
Mus., Vol. II, 1894, p. 266; Brown, Proc. Acad. Nat. Sci. Phila., 
1901, p. 68; Dirmars, Reptile Book, 1907, p. 332. 
Contia occipitalis var. annulata Garman, Mem. Mus. Compr. Zool., 
Cambr., Vol. VII, No. 3, 1883, pp. 91, 164. 
