212 ZOOLOGY. 



constructing tlie inferior rim of the orbit. A black vitta along the npper margin of upper max- 

 illary plates extending posteriorly along a portion of the neck. 



Syn. Dnjophis vlttatus, Grd. Proc. Acad. Nat. Sc. Philad. VII, 1854, 226. 



Descr. The entire length of the specimen figured is forty-seven inches, of which eleven belong 

 to the tail. The head measures about one inch and an eighth. Its upper surface is flattened; 

 the inferior one subconvex, and the sides perpendicular. The eye is large and circular^ and its 

 diameter is comprised about six times in the length of the head. The snout is tapering, the 

 upper jaw protruding considerably over the lower. The rostral plate is ratlier small, subcres- 

 centic, convex anteriorly, and depressed upon its middle surface. It is obliquely situated at the 

 inferior surface of the snout, showing but a very narrow edge in a view from above (fig. 2). The 

 prefrontals are twice as long as broad upon the middle of their length; they belong exclusively 

 to the upper surface of the head. The postfrontals are much larger than the latter, one-third 

 longer upon their upper surface, and extend upon the sides of the head until they reach the 

 upper labials. The vertical is elongated and slender, subtruncated anteriorly, and subacute 

 posteriorly, engaging between the inner margins of the occipitals. The latter are as long as 

 the vertical, but broader anteriorly; their external margin being defined by an undulating line. 

 The superciliaries are a little longer than the postfrontals, subtriangular in shape; the summit 

 of the triangle directed forwards. There is a long and narrow nasal, in which, and rather in 

 advance of the middle of its length, the nostril opens subangular in shape. There is no loral; 

 but the lateral expansion of the postfrontals fills up the space between the nasal plate and a 

 large anteorbital, much broader ujjwards than downwards, slightly visible in a view from 

 above (fig. 2). Its anterior angle fits a notch in the posterior margin of the postfrontals, upon 

 the line of demarcation between the sides and upper part of the head. The postorbitals are 

 rather small, and three in number; two upon an anterior line, the lowermost being much the 

 smallest of the two. A third, very small, is situated immediately behind the latter. Three 

 large and subequal temporals terminate the series of cephalic plates and shields. The upper 

 labials are nine in number ; the posterior one being the longest and largest of all, and the 

 anterior one the most slender. The fifth, sixth, and seventh constitute on the right side the 

 inferior rim of the orbit, though the fifth and seventh only in part. On the left (fig. 3) thei'e 

 is one labial less. The lower labials are likewise nine in number ; the fifth and sixth, situated 

 beneath the eye, are the largest; the others diminishing gradually in size towards the anterior 

 and posterior regions. The symphyseal or anterior odd lower labial is small, and rounded ex- 

 teriorly. There are three pairs of elongated mental shields, the anterior pair reaching the 

 margin of the jaw between the symphyseal and the first lower labial. The subgular scales are 

 well developed and elongated. 



The body is subcylindrical, much thinner anteriorly than posteriorly, the neck having about 

 the thickness of the tail upon its anterior third. The scales are smooth, elongated, and acute 

 posteriorly, constituting seventeen longitudinal rows ui^on the middle of the body, and twelve 

 towards its posterior extremity. The external row, nearest to the abdominal scutella3, is com- 

 posed of the largest scales. The abdominal scutellai, one hundred and ninety-five in number, 

 are rather wide, convex upon their posterior margin; the posterior two are bifid. The tail is 

 very slender, and tapering to a point ; there are six rows of scales upon its anterior portion, 

 near its origin ; they are, moreover, broader and shorter than those on the body. The subcaudal 

 scutella3 constitute a double row to nearly the tip of the tail, where scutellas and scales assume 

 a uniform aspect. One hundred and sixty-five pairs of the latter may distinctly be enumerated. 

 Beyond that number verticiles of scales surround the remaining portion of the tail. 



Abd. sc. 193-f2. Subc. sc. 165. Dors, rows 17 and 12. Total length, 47 inches; tail, 18 inches. 



The coloration must be much altered by the action of the alcoholic liquor in which the specimen 



