rally without the yellow variegations, and are everywhere of the same tint as
the edges of those which are situated nearer to the base of the tail. Eyes,
shining brown. In some specimens of this variety very faint remains of
yellow markings are occasionally to be seen upon the scales of the back and
sides, clearly indicating that had they been secured in an early stage of their
existence, they would have required to have been classed with the variety
next to be described.
F orm, &c.-—Head distinct from the neck; body moderately slender and
fusiform, the thickest part rather nearer to the head than the tip of the tail;
form subcylindrical, the belly flattened and very broad; tail long, tapered, and
pointed, its figure somewhat cylindrical, the under surface slightly flattened.
The head is short, rather clumsy, and distinctly quadrangular, its breadth
and height nearly equal; the upper surface is slightly convex, the sides
almost perpendicular, with a slight longitudinal concavity in front of the eyes ;
the nose is obtuse, almost truncated ; the lips are coated, each with a row of
large quadrangular scales. The mouth is armed with six rows of teeth, and
the two or three last teeth of each maxillary row are much larger than any of
the others, and grooved throughout their whole length. They point almost
directly backwards, and are either firmly fixed upon the maxillary bones or
slightly moveable, and are in a great measure concealed by the pulpy sheath,
with which they are encircled. Within this sheath there are also a number of
recumbent fangs, evidently destined to supply such of the fixed ones as
may from time to time disappear. All the rest of the teeth are small, cylindrical,
recurved, and pointed. The salivary * and lachrymal glands are
moderately large. The eyes are very large, the corneas slightly convex,
and the pupils circular. The nostrils are situated towards the middle
of the nasal plates, nearly circular, and opening outwards and backwards.
The plates covering the upper surface of the head are ten in number; the
rostral one is rather small, subtriangular, or indistinctly five-sided, its apex
lies between the anterior frontal plates, and its base forms the margin of the
upper lip, and is indented with a deep crescent-shaped emargination; the
anterior frontal plates are four-sided, the hinder and outer sides longest; the
posterior frontal plates considerably larger than the anterior ones and of an
irregular quadrangular shape, the irregularity depends principally upon the
elongation of the anterior and outer angle of each scale which extends down*
M. Duvernoy is of opinion (Annul, de Scienc. Nat. tom.'26. p. 149.) that the anterior portion only of
the glandular structure which is found under the integuments of the upper lip is for the secretion of saliva:
the posterior portion, he thinks, is distinct from the anterior, and is adapted for the secretion of poison.
We have tried, but in vain, to discover grounds for entertaining a Tike opinion.
wards on the side of the head to join the loral scale between the anti-ocular and
rostral scales, the hinder sides of the posterior frontal plates are slightly arched
or indistinctly two-sided ; the vertical plate is indistinctly six-sided, the two
hinder sides extend backwards and inwards, and terminate in an obtuse
angular point which lies in contact with the line where the two occipital plates
join, the lateral sides of the plate are longest; the palpebral plates are rather
narrow and lengthened, the lateral sides of each are nearly parallel, the
anterior extremity somewhat rounded, and the hinder one, which is the
broadest, indistinctly two-sided, the innermost of the two sides being considerably
longer than the outermost; occipital plates large, irregularly five-sided,
and considerably wider at the base than the apex, the last, though nearly
square, is nevertheless slightly two-sided. Rostral scale small, oblong, and
quadrangular ; loral scale also small and quadrangular ; anterior ocular scale
quadrangular, concave, and broadest posteriorly, its upper and hinder angle
extending in the form of an angular elongation between the posterior frontal
and palpebral plates, in which situation it forms a portion of the covering of
the upper surface of the head. Post-ocular scales three, forming a semicircle
round the outer canthus of the eye ; temporal scales four or five in number,
smooth, unequal, in regard of size, and somewhat six-sided. The scales on
the back and sides of the-neck, close to the occipital plates, small and smooth,
some of them quadrangular, others more or less diamond-shaped, all rather
irregularly disposed ; the scales behind these are carinated and disposed in
arched transverse rows, the convexity of each row towards the head. The
form, &c., of the scales vary at different parts of the rows; the one
which, from its situation, may be called the dorsal scale is narrow towards
the base, and broad and semicircular at the point, this scale has a distinct
carina extending along its centre. The scales on each side of the dorsal
one are somewhat ovate, their points either angular, subtruncate, or obtuse,
the upper edge of each of these scales is nearly a straight line, the lower,
very convex, and much arched ; the carina close to the superior edge, and
generally terminating on the upper margin at some distance behind the points
of the scales; the two scales nearest to the abdominal plates on each side
are larger than the others, very wide at the base, and rounded at the point,
their figure is somewhat triangular; the carina in these is nearly central.
The hinder margin of each row of scales overlaps more or less of the base of
the row immediately behind it, and the outer edge of each of the scales
which compose the rows is more or less covered by the inner edge of the scale
immediately external to .it, and in this way there is a double kind of
imbrication. As far as the base of the tail the above are the characters and