BASCANION. 93 



Genus BA.SCAI¥I0IV, Baird & Girard. 



Gen. Char. Body slender, elongated. Tail very long. Head 

 narrow, deep, long. Eyes very large. Postorbitals 2 ; anterior 2, 

 upper very large, lower very small, in a notch between the 2d and 3d 

 labials. Fourth labial produced up behind the eye to meet the lower 

 postorbital. Loral one ; nasals two. Vertical much elongated and 

 narrow, concave externally. Dorsal rows of scales 17, all perfectly 

 smooth, and subhexagonal. Abdominal scuteilae 170-200 ; posterior 

 one divided : subcaudal 90-110, all bifid. Colors black or olive. 

 Uniform above; lighter below: skin between the scales black. 

 Young blotched. 



1. Hascaniou constrictor, B. & G. — "Vertical diminishing for 

 half its length, then parallel. Centre of eye over the 4th labial. In the 

 adult, color lustrous pitch-black, above and beneath greenish black, some- 

 times tinged -with greenish white. Chin and throat white. The young are 

 olive, with rhomboidal dorsal blotches ; beneath greenish white. 



Stn. Coluber constrictor, Linn. Syst. Nat. I, 1766, 385. — Gm. Linn. Syst. 

 Nat. ed. xiii, I, iii, 1788, 1109.— Hael. Journ. Acad. Nat. Sc. Philad. V, 

 1827, 348; and Med. & Phys. Res. 1835, 112.— Schl. Ess. Phys. Serp. Part, 

 descr. 1837, 133. PI. v, figs. 3 & 4.— Storek, Rep. Rept. Mass. 1839, 225.— 

 HoLBR. N. Amer. Herp. Ill, 1842, 55. PI. xi.— Thomps. Hist, of Verm. 

 1842, 117.— Dekat, New York Fauna, Rept. 1842, 35. PI. x, fig. 20. 



Hierophis constrictor, Bonap. Fn. Ital. II, 1841. Art. Col. leopard. 



Vipera niyer, Catesb. Nat. Hist. Carol. II, 1743, 48. Tab. xlviii. 



Black Snake, Kalm, Reise N. Amei-. II, 1764, 202.— Penn. Arct. Zool. 

 Suppl. II, 1792, 92. 



Vertical plate much longer than broad, pentagonal, anterior margin 

 convex, the lateral strongly concave, the plate rapidly diminishing 

 to half its length, thence nearly parallel, terminated by a rather ob- 

 tuse angle ; a little shorter than the occipitals. Superciliaries large, 

 rather broad. Rostral rather broad and high, wedged to a slight 

 extent between the prefi'ontala. Eye large, its centre before the 

 middle of the commissure, and over the 4th labial. The lower 



