May, 1844.] 61 



and the two anterior orbitar, which extend upon the top of the 

 head; rostral plate large, triangular, rounded in front, its apex 

 projecting backwards a short distance toward the two anterior 

 frontal plates; anterior frontal rather large, quadrangular; pos- 

 terior irregularly quadrilateral, extending upon the side of the 

 head, where they are in contact with the anterior orbital, the loral 

 and the nasal plates ; vertical plate pentagonal, much broader in 

 front, pointed behind ; supra-orbital irregularly quadrilateral, 

 smooth, convex above, projecting very slightly over the eye ; oc- 

 cipital large, pentagonal ; nasal plates ten in number with the 

 nostril placed between them; but one anterior orbitar plate, ir- 

 regular in shape, much broader above ; posterior frontal two in 

 number, small, the upper the larger of the two; frenal region very 

 slightly grooved ; there are nine plates upon the upper jaw, the 

 seventh the largest, the fifth and sixth going to form the inferior 

 margin of the orbit; tongue long, bifid, enclosed in a sheath at its 

 base, two rows of teeth in the upper jaw, nostrils large, placed near 

 the snout, immediately behind the canthus rostralis, which is well 

 marked, but much less distinct than in the preceding species ; body 

 long, slender, covered with quadrangular scales, strongly carinated 

 both upon the back and sides; the inferior row is the largest; ab- 

 domen flattened, tail long and slender, tapering to a point, flattened 

 inferiorly. Abdom. scuta 159, subcaud. 153. 



Colour. Head, body, and tail grass-green above ; abdomen and 

 under part of tail of a lighter colour, approaching to milky white 

 upon the neck ; a dark coloured vitta extends on each side of the 

 flattened surface of the abdomen, from near the neck to the anus. 



Dimensions. 



Length ofhead, - 

 Greatest breadth, 

 Breadth between the orbits posteriorly, 



" " " anteriorly, 



Length of body, .... 



" tail, 



Greatest circumference, 



Habitat. Liberia, W. Africa. 



