PLATURUS COLUBRINUS. 183 



2. Platurus colubrinus, Wagl. 



Spec. Char. — Dorsal scales disposed upon twenty-three longitudinal 

 series. Three rows of scales along the middle region of the side of 

 the tail. Body annulated with black; intervening spaces equal 

 in width to the rings on the dorsal region, and much broader upon 

 the abdomen. Fronto-rostral and supraocular regions yellow. Upper 

 labialsj part of lower labials, and middle region of the throat yellow 

 also. 



Syn. — Hydrus colubrinus, ScHN. Hist. Aiiiph. I, 1799, 238. 

 Platurus colubrinus, Wagl. Nat. Syst. Amph. 1830, 166. 



ITi/drophis colubrinus, Schl. in Faun. Japon. 1833, PI. x; & Ess. Phys. Serp. II, 

 1837, 514, PL XVIII, figs. 18-22.— Duvern. in Cuv. R^gn. Anim. Illustr. 1846, 130, 



PI. XXXVI. 



Descr. — The general aspect of this species is very similar to the 

 preceding one, from which it is not regarded as distinct by several 

 writers. There are but minor differences to be noticed in the structure 

 of the cephalic plates : the vertex plate is larger and more elongated; 

 the postfrontals larger than the prefrontals, all of which being irregular 

 in their outline. An odd frontal may likewise be observed either upon 

 the line of contact of both pairs, or else extending to the vertex plate, 

 between the postfrontals. There are three lower labials in one series 

 upon each side of the symphyseal. The mental shields are nearly 

 equal sized, but, in the anterior pair, they are quadrangular, whilst the 

 posterior are tapering posteriorly. In either species, we observe nine 

 scales, in a longitudinal series between the mental shields and the hrst 

 abdominal scutella. 



The scales are smaller than in P. laticaudatus, lozenge-shaped, and 

 disposed upon twenty-three longitudinal series, nearly uniform in size. 

 In both species, the body is convex above and flat beneath. There 

 are two hundred and thirty-two abdominal scutellae; the posterior two 

 being subdivided. The tail and subcaudal scutellae present the same 

 structure as in P. laticaadatus, with this difference, that there are 

 three longitudinal series of scale-like scutellae along the lateral middle 

 region of that organ. 



The fronto-nasal and the supraocular regions, and the edge of the 

 snout are yellow, thus leaving but a narrow black bar behind the eye. 



