TRIMERORHINUS RHOMBEATUS.
stripes, which generally commence about the middle of the body, sometimes
extend almost to the point of the tail. From the eye a stripe of the same
colour as the spots of the back, extends backwards to the neck, and in many
specimens inclines inwards and joins its fellow of the opposite side, and so
forms, on the hinder part of the head, a mark of a shape like a horse-shoe.
Besides these spots and stripes, there is also on each side a narrow, livid-
greenish line, extending from head to anus, along the row of scales nearest to
the abdominal plates; eyes brown.
F orm, &c.—Head rather small, subquadrangular, the temples bulged,
the hind head rather broader than the neck, the nose pointed; the loral plate
quadrangular; the preocular plate narrow inferiorly, broad and subquadrangular
superiorly; plates of upper lip, exclusive of rostral, eight; of lower,
not including mental, eleven; temporal plate long and irregularly six-sided;
rostral plate narrow superiorly, and reaches to the anterior edge of the frontonasal
plates, inferiorly rather broad and the under surface concave; frontal
plate long and five-sided, the two sides forming the hinder extremity short,
and only slightly inclined backwards. Body subcylindrical, inferiorly rather
flattened; the scales long, narrow, subovate, much imbricate, and arranged
in seventeen oblique transverse rows; tail long, cylindrical, and tapered to a
point, which consists of a horny subacute spine. Abdominal plates 168 to 170.
Subcaudal scales 70 to 75. Length of some specimens, 24 inches, of which the
tail generally measures about 6 inches, or one-fourth of the total length.
This snake occurs throughout the whole of Southern Africa, and is generally found in dry
barren situations, but not unfrequently also in grassy districts. It moves from place to place
with great rapidity, and feeds on insects and reptiles of a size it can secure and devour, such
as the small lizards which abound in the situations in which it is common.
The form of the rostral plate and its extension on the head, till it reaches the fronto-nasal
plates are, in conjunction with the mode in which the nostrils are formed, characters which at
once denote the genus.
The Schaap Sticker varies considerably in colour, and the markings differ in different individuals.
In young examples, the spots on the body are more regular and better defined than in
those of advanced age, the dark rings are less manifest, and the ground colour is commonly
pale yellowish-grey. In the young, and also in the adults, the colour of the belly and under
surface of the tail is often of a livid greenish tint, and variegated with dark blackish-green
blotches, as already noticed.