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 XIV.; 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 ol 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. I he young, as figured in Plate 
XVII., 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 Zwartc 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 moderate sprinkling, at least, of dwarf shrubs. 
The young, again, are commonly discovered upon stony hillocks or rising ground in the neigh- 
bourhood of plains. Full and half-grown specimens conceal themselves up in holes or sub- 
terranean 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 other- 
wise, 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, aud 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 of pressure that immediately becomes almost 
un supportable. 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. 
