DENDROPHIS (PHILOTHAMNUS) SEMIVARIEGATA.
the body- are subovate, and disposed in oblique rows across the body, the rows
most distinct towards the head ; the scales of the rows laterally overlap each
other more or less, that is, the dorsal edge of each scale lies more or less over
the outer edge of the one inside of it. The points of the scales of each row,
for they do not laterally overlap to a degree to render the hinder edge of the
row quite continuous, extend slightly beyond the base of those of the following
row, or in other words, they are imbricate. Towards the tail the
scales increase in width, and cease to exhibit the arrangement observed
towards the head; they are large, six-sided, slightly imbricate, and not
disposed in rows, as towards the head. Each row towards the latter consists
of fifteen scales, the middle or dorsal one rather dilferently formed to those
on each side of it. Body sub-cylindrical above, flattened below ; tail rounded
superiorly, strongly angular at each side, and very flat beneath, its apex a
slender horny prickle. Abdominal plates, 207; subcaudal scales, 112; tail
nearly one-fourth of the whole length ; adult specimens from 3 feet to 3-J feet.
The abdominal plates have a keel or angle towards each extremity, and
their hinder edge at the angles is emarginate.
Y oung. Plate LX. In most specimens the ground colours resemble those
of the adult, but the number of black bars are more numerous, and extend
over a greater portion of the body. The lower portions of the sides are
variegated with small black spots, eyes coloured as in the adult.
A full grown specimen of this species was obtained on the Bushman Flat, and several
young ones, in heaps of stones, in the country beyond Kurrichaine. It climbs underwood
with facility, and upon it, probably, seek its food.
This and two other South African snakes (to be hereafter described) may prove only
aberrant species of Dendrophis, yet, in the absence of sufficient materials to enable us to judge
correctly, I have thought it best to regard them, for the present, as members of a subordinate
group. They exhibit many of the characters of-the true Dendrophis; and taking D. picta and
Boeii as typical species, we find in Philothamnus the same sort of teeth; the nostrils similarly
formed; the same form of pupil, and the same keel or angle towards each extremity of
the abdominal plates. The arrangement and form of the scales, particularly towards the
head, are, however, very different. In both groups they are arranged in rows; in Dendrophis,
the rows extend nearly directly across the body; in Philothamnus, they are more or less
oblique ; in Dendrophis, the scales overlap each other laterally, to admit of the free distension
of the skin ; in Philothamnus, if that occurs, it js only to a very trifling extent; in Dendrophis,
the points of the scales are so close on each other that the hinder edge of each row of scales
appears a continuous line; in Philothamnus, the points are apart, so that the line behind appears
serrated or broken. This peculiarity in the arrangement of the scales proclaims the species,
of which we have formed a subordinate group, to be either typical species of an aberrant
group, or aberrant species of a normal group.
DENDROPHIS SEMIYARIE GAT A. (Young.)
I Reptilia—Plate 60.)