COLUBER CANUS. 



the form of a cross, and the under parts with transverse blotches of the latter 

 colour, either at the extremities of the plates, or towards their centres, or at 

 both. In some specimens the spots are disposed in four regular rows ; in 

 others they are in two rows, one on each side, and each spot shaped like a 

 sand glass, being narrow in the middle, and widest at the extremities. 



Form, &c. — Figure sub fusiform, and somewhat quadrangular in young and 

 middle-aged individuals; subcylindrical in adults; head quadrangular, 

 rather small, posteriorly as wide as the neck, anteriorly narrow, and termi- 

 nating in an obtuse point ; side of head behind eye convex ; portion 

 of the side in front of eye flat and perpendicular. Gape rather large, 

 and the angles of the mouth considerably behind the eyes. From the head 

 the body gradually increases in thickness till it reaches its extreme, which is 

 generally about midway between the nose and anus ; from that point it gra- 

 dually decreases towards the tail, which is in most specimens thicker and 

 shorter, in proportion to the total length, than in the majority of reptiles of 

 this genus. The point of the tail, particularly in adult specimens, is com- 

 monly blunt and rounded. The plates covering the upper surface of the head, 

 including the labial, a portion of which is so reflected as to cover the anterior 

 extremity of nose, are ten in number, viz. 1 labial, 2 nasal, 2 frontal, 2 

 supra-ocular, 1 vertical, and 2 occipital plates; the labial at its base, 

 which constitutes a portion of the edge of upper lip is notched, the notch 

 being a curve, the convexity of which is directed upwards; the shape of this 

 plate is triangular, its apex reaching the point at which the nasal plates come 

 in contact anteriorly ; the vertical plate somewhat triangular, and more or less 

 distinctly six-sided ; its apex lying between the occipital plates ; labial plates 

 of upper lip six or seven, those towards angles of mouth largest, of lower lip 

 eleven or twelve, exclusive of the central one, covering the apex of the lower 

 jaw ; postocular plates generally two, anti-ocular plates one or two. Eyes 

 small and deeply set ; nostrils small, widest behind, pointed in front, and 

 situated much nearer to the point of the nose than the eye. Scales of the 

 body rhomboidal and disposed in rows, which run obliquely across the bod\ 

 from the abdominal plates on one side to those of the other, each row 

 generally consisting of twenty-seven scales ; subcaudal scales six-sided, the 

 two central sides longest ; the tip of the tail usually covered with a hard 

 elastic, and somewhat horny sheath, the apex of which is either blunt or 

 aculeated. The abdominal plates vary in number in different specimens, 

 ranging from 172 to 209 ; the subcaudal scales from 60 to 84, and there is 

 no reason for supposing that the number is in proportion to the size of the 

 specimen. The usual length of an adult specimen is from five to six feet, but 

 individuals are frequently obtained which measure even more than seven feet. 



