562 PROCEEDINGS OF THE ACADEMY OF 



dorsal region, and lineated sides, a dark line running through the centre of each 

 , row of scales upon the latter region and upon the ends of the gastrosteges. The 

 intervals between these lines may be variously shaded. When a light color 

 appears between each, we have the form tamiatus. (U. S. Pac. R. R. Expl. 

 Rept. x. Beckwith's Rept. PL xxiii.) When the intervals involving the ends of 

 the gastrosteges, the first, second and half the third rows of scales, are dark, half 

 the third and fourth being bright yellow, we have lateralis or Schotlii. (Mex. 

 Bound. Surv. pi. 17.) Sometimes only the interval between the lines of the 

 second and third rows is dark ; sometimes this occurs, the inferior half of the first 

 row being also shaded. The uniform olive brown of the back is formed by the con- 

 fluence of the widened longitudinal bands ; the exterior basal portions of the 

 dorsal scales, are however sometimes yellow, like the ground upon the sides. 

 One sp. California. Dr. Heermann. 



One sp. Arizona. Smiths. Inst. 



Herpetodryas Boie. Type H. carinatus. 



Bullet, de Sci. Nat. et Geol. Octob., 1826, p. 237. Macrops Wagl. Nat. Syst. 

 Amphib. 1830, p. 



203. H. carinatus {Boie ) Schlegel. Herpetologists have distinguished two 

 species as confounded in the H. cjarinatus of Schlegel's Essai, and have 

 characterized them as possessing, the one, smooth scales, the other, cari- 

 nate. After a careful study of our specimens, we have arrived at the con- 

 clusion that there is no ground for ^regarding one series of specimens possess- 

 ing carinae upon the scales, as representing a species distinct from another 

 series, whose scales are keelless. Specimens in which two or three labials 

 enter the orbit and which have the anal divided, differ in this respect, as 

 do also those with an entire anal plate, and three or two upper labials 

 entering the orbit. A specimen from near Rio Janeiro is obviously 

 Ifatrix scurrula of Wagler, (Spix, Serp. Braz. pi.) Another specimen from 

 Surinam is quite as slender as Ahaetulla pi eta. In color, specimens vary 

 from black olivaceous with a yellow dorsal line, and spots upon the first row of 

 scales upon the tail, to gray brown with oblique transverse bands. A speci- 

 men received from the Garden of Plants, exhibits two preoculars, and three 

 or four postoculars. That a careful anatomical investigation may demon- 

 strate the existence of several species among these individuals, is not improb- 

 able. 



Besides the synonymes ordinarily quoted under the " species" f u s c u s and 

 carinatus, there may be added, Coluber Spixii Hallowell, Proc. Phil. Acad, 

 ii. p. 241, and C. Pickeringii Hallow. 1. c. p. 242, 



Ten sp. Surinam. Dr. Hering. 



Three sp. (Types Hallow, sp.) Near Caraccas. Mr. Ashmead. 



One sp. (" Dendrophis viridix 0, B.") Para. Col. Abert. 



One sp. Surinam. Dr. Colhoun. 



One sp. Rio Janeiro. ? 



One sp. ? Gard. Plants in ex. 



Three sp. ? ? 



204. H. sebastus nobis. 



As a representative of its genus, this species is of a very elongate and com- 

 pressed form, with the scales arranged in transverse series, and with two 

 medial dorsal rows, larger than the others ; the dentition isodont. 



The specific characters are as follows : tail one-third the total length. 

 Scales large, in ten longitudinal rows, entirely smooth. Anal shield entire. 

 Head distinct from the neck, lanceolate. Eye large, superciliaries prominent. 

 Upper head shields large. Vertical elongate, broad anteriorly, lateral borders 

 concave, convergent. Post-frontals bent upon the sides. Rostral as high as 

 broad. Nostril between two nasals, each of the latter higher than broad. 

 Loreal rectangular, longer than high. One preocular scarcely reaching the 

 vertical. Postoculars two, inferior largest ; the two bounded posteriorly by the 



[Dec. 



