COLUBER CANUS.
Scarcely are any two specimens of this snake marked and coloured alike: hence, as regards it,
neither the form of the spots nor the tints of the colours are of any real value as diagnostic
characters. Though such is the case, it must, nevertheless, be admitted, that there exists in
specimens certain general resemblances which enable the eye that has become familiar with
the appearance of one or two specimens to recognize without much difficulty, all the other
modifications which present themselves. The colours most commonly noticed in adults are those
represented in Plate X IV .; but many individuals are obtained in which the colours are lighter,
and others in which they are much darker./ The variety figured in Plate XV. is less common,
and although some diversity occurs in the arrangement of the spots in different specimens, yet
there is never that discrepancy which is calculated to raise a doubt as to the identity of any
two real examples of the variety. Comparatively rare as this variety is, the one represented in
Plate XVI. is still less frequently procured, and specimens so coloured are very seldom
obtained; that is, the ferruginous tinge is rarely seen of such a depth, though specimens in
which it exists of a lighter hue are not very uncommon. The young, as figured in Plate
X V II., exhibits the appearances most characteristic of that age ; and although many examples
are procured in which the configuration of the spots and the fashion of the bands are more or
less varied, yet there is that in all' of them which clearly indicates their species. The colours
of the young are also variously modified, but not to such a degree as those of adults or half-
grown specimens.
Each of the kinds represented are considered by the European settlers and the aboriginal
inhabitants of Southern Africa as distinct species, and that figured in Plate XIV. is known
throughout the colony by the appellation of Zwarte Slang, or black snake. Adults and
middle-aged individuals are generally found upon dry plains, especially those of which the soil
is loose and sandy, and whose surface bears a modierate sprinkling, at least, of dwarf shrubs.
The young, again, are commonly discovered upon stony hillocks or rising ground in the neighbourhood
of plains. Full and half-grown-specimens conceal themselves up in holes or subterranean
burrows, except when hunger or a desire to bask in the sun urges them to appear
above ground; and if they are discovered whilst so engaged, they generally fly to the nearest
hiding places. Though such is their general habit, it often occurs that they act otherwise,
and await the approach of man without any appearance of fear. On such occasions they
manifest considerable boldness, and if pressed or closely assailed they prepare for battle,
by raising the head and eight or ten inches of the body almost perpendicular, at the same time
alternately darting the tongue out of the mouth, and retracting it with great velocity. When
in the first instance they fly, it sometimes happens, if they be pursued, that they suddenly turn
upon their pursuers, and evince a disposition to act on the defensive. The strength of a full-
grown specimen is very great, and I have myself, more than once, had my hand benumbed by
permitting one to wind its body spirally round my arm while holding its head in my hand.
The moment it is satisfied that its body is properly coiled, it throws the muscles into a state of
violent contraction, which produce a degree-bf pressure that immediately becomes almost
unsupportable. The consequence of such pressure is soon evident; the parts below those,
round which the body is turned, become benumbed and powerless ; the fingers lose their ability
to detain the head, and the moment the latter gets free/.the body is instantly uncoiled by the
will of the reptile, which then falls to the ground.