HETERODOX. 55 



nated on the back of head as well as elsewhere to the tip, the more 

 prominent rostral, (the line from the tip to the lower posterior angle 

 of the last labial passes over the eyeball,) &c. will at once distin- 

 guish it. 



A much mutilated, but much larger specimen from New Braunfels 

 agrees with this, although the rostral is proportionally less ; in other 

 characters it is very similar. The intervals between the light bars, 

 and the sides at their extremities are, however, much darker. 



A small specimen from ludianola has much the same distribution 

 of color as described in the young H. plat?/7-hi7ws. The principal dif- 

 ferences are seen in the larger head, stouter body, shorter occipitals, 

 narrower dark line across the supereiliaries and vertical, broader scales 

 anteriorly, &c. The ground-color is mottled chestnut, with subquad- 

 rate brown blotches, indistinct at the outer edges, a circular dark spot 

 opposite each light dorsal interval, like the dorsal series surrounded 

 by a lighter areola ; beneath each dark spot a pair still smaller. 

 Below greenish white, blackish posteriorly, with narrow blotches of 

 black in front. Distinct patch from eye to the last upper labial. 

 Indianola. 130+1.58.23. 26.6. Col. J. D. Graham. 



" 129+1.51.25. 11.2. " 



Nexo Braunfels, Tex. 121+1.56.25. 27.6. F. Lindheimer. 



3. Ileterodon nig'cr, Tboost. — Vertical plate as long as the oc- 

 cipitals. Rostral pvoniineiit. Dorsal rows of scales 25, the exterior smooth, 

 the 2d row obsoletely carinated, the rest with the scales distinctly carinated, 

 the cariuiB extending quite to the tip. Uniform black above, slate-color 

 beneath. 



Syn. Vipera nir/ra, Catesb. Nat. Hist. Carol. II, 1743, 44. PI. xliv. 



Scytale niger, Daud. Hist. Nat. Rept. V, 1799, 342. — Harl. Journ. Acad. 

 Nat. Sc. Philad. V, 1827, 367 ; and Med. & Phys. Res. 1835, 130. 



Coluber cacodemon, Shaw, Gen. Zool. Ill, 1802, 377. PI. cii. 



Coluber thraso, Harl. Med. & Phys. Res. 1835, 120. 



Ileterodon niger, Troost. Ann. Lye. Nat. Hist. N. York, III, 183G, 186.— 

 ? Holer. N. Amer. Herp. 1st ed. II, 1838, 105. PI. xxiii ; and 2d ed. Ill, 

 1842, 63. PI. xvi. 



Black Viper ; Spreading Adder. 



Postfrontals large, extending to the loral. Prefrontals smaller. 

 Azygos rather large, separating the prefrontals entirely, and 

 the postfrontals anteriorly: in a line with the rostral. Ilostral 



