41. SONORA 



195. Sonora semiannulata Baird & Girard 



BicoLOR Ground Snake 



Plate 96 



Sonora semiannulata Baird & Girard, Cat. N. Amer. Rept., 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 

 Denburch & Slevin, Proc. Cal. Acad. Sci., Ser. 4, Vol. 5, No. 4, 

 1915, p. 100; Stejneger & Barbour, Check List N. Amer. Amph. 

 Kept., 1917, p. 92; Van Denburgh & Slevin, Proc. Cal. Acad. 

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



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

 3, 1883, pp. 90, 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. 100th Merid., Vol. V, 1875, P- 537. pl- 

 18, 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. 33' ; Strecker, 

 Baylor Bulletin, Vol. XVIII, No. 4, 191 5, 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; Bailev, N. Amer. Fauna, No. 25, 

 1905, pp. 35, 47; Ellis & Henderson, Univ. Colorado Studies, 

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



Chionactis isozonus Richardson, Proc. U. S. Nat. Mus., Vol. 48, 191 5, 

 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- 



