41. SONORA 863 



195. Sonora semiannulata Baird & Girard 



BICOLOR GROUND SNAKE 



Plate 96 



Sonora semiannulata BAIRD & GIRARD, Cat. N. Amer. Kept., Pt. I, 

 Serpents, 1853, p. 117 (type locality, Sonora, Mexico); BAIRD, 

 Rep. Pac. R. R. Surv., Vol. X, Pt. Ill, 1859, p. 15, pi. XXXIII, 

 fig. 88; BAIRD, U. S. Mex. Bound. Surv., Vol. II, 1859, Rept., p. 

 21, pi. 19, fig. 3; COPE, Bull. U. S. Nat. Mus., No. i, 1875, p. 36; 

 YARROW, Bull. U. S. Nat. Mus., No. 24, 1883, p. 87; VAN DEN- 

 BURGH & SLEVIN, Proc. Cal. Acad. Sci., Ser. 4, Vol. 3, p. 411; VAN 

 DENBURGH & SLEVIN, Proc. Cal. Acad. Sci., Ser. 4, Vol. 5, No. 4, 

 1915, p. ico; STEJNEGER & BARBOUR, Check List N. Amer. Amph. 

 Rept., 1917, p. 92; VAN DENBURGH & SLEVIN, Proc. Cal. Acad. 

 Sci., Ser. 4, Vol. XI, 1921, pp. 29, 38. 



Contia semiannulata CARMAN, Mem. Mus. Compr. Zool., Vol. VIII, No. 

 3, 1883, pp. go, 164. 



Contia isozona COPE, Proc. Acad. Nat. Sci. Phila., 1866, p. 304 (type 

 locality, Arizona); COPE, Bull, U. S. Nat. Mus., No. i, 1875, 

 p. 36; YARROW, Surv. W. looth Merid., Vol. V, 1875, p. 537, pi. 

 1 8, fig. i; GARMAN, Mem. Mus. Compr. Zool., Cambr., Vol. VIII, 

 No. 3, 1883, pp. 92, 164; BOULENGER, Cat. Snakes Brit. Mus., 

 Vol. II, 1894, p. 266. 



Contia episcopa isozona COPE, Bull. U. S. Nat. Mus., No. 17, 1880, p. 

 21 ; YARROW, Bull. U. S. Nat. Mus., No. 24, 1883, p. 87; COPE, 

 Proc. U. S. Nat. Mus., Vol. XIV, 1892, p. 601; BROWN, Proc. 

 Acad. Nat. Sci. Phila., 1901, p. 67; BROWN, Proc. Acad. Nat. Sci. 

 Phila., 1903, p. 553; DITMARS, Reptile Book, 1907, p. 331; STRECKER, 

 Baylor Bulletin, Vol. XVIII, No. 4, 1915, p. 37. 



Chionactis episcopus isozonus COPE, Report U. S. Nat. Mus. for 1898, 

 1900, p. 939, fig. 239; BRANSON, Kansas Univ. Sci. Bull., Vol. II, 

 No. 13, 1904, p. 416, fig. 34; BAILEY, N. Amer. Fauna, No. 25, 

 '95> PP- 35> 47? ELLIS & HENDERSON, Univ. Colorado Studies, 

 Vol. X, No. 2, 1913, p. 101. 



Chionactis isozonus RICHARDSON, Proc. U. S. Nat. Mus., Vol. 48, 1915, 

 p. 426. 



Description. Head but little wider than neck, rather 

 flat-topped, temporal regions not much swollen. Snout 

 rounded, not greatly depressed, not pointed in profile, pro- 



