BUCEPHALUS CAPENSIS. 
birds, &c., while they are only partially within the mouth ; and from the circumstance of 
these fangs being directed backward, and not admitting of being raised, so as to form an angle 
with the edge of the jaw, they are well fitted to act as powerful holders, when once they 
penetrate the skin and soft parts of the prey which their possessors may be in the act of swal- 
lowing. Without such fangs escapes would be common ; with such they are rare. 
The natives of South Africa regard the Boom-slange as poisonous ; but in their opinion we 
cannot concur, as we have not been able to discover the existence of any glands manifestly 
organized for the secretion of poison. The fangs are enclosed in a soft pulpy sheath, the 
inner surface of which is commonly coated with a thin glairy secretion. This secretion 
possibly may have something acrid and irritating in its qualities, which may, when it enters 
a wound, occasion pain and even swelling, but nothing of greater importance. The Boom- 
slange is generally found upon trees, to which it resorts for the purpose of catching birds, upon 
which it delights to feed. The presence of a specimen in a tree is generally soon discovered 
by the birds of the neighbourhood, who collect around it, and fly to and fro, uttering the most 
piercing cries, until some one, more terror-struck than the rest, actually scans its lips, and 
almost without resistance becomes a meal for iis enemy. During such a proceeding the snake is 
generally observed with its head raised about ten or twelve inches above the branch round which 
its body and tail are entwined, with its mouth open, and its neck inflated, as if anxiously 
endeavouring to increase the terror which it would almost appear it was aware would sooner 
or later bring within its grasp some one of the feathered group. Whatever may be said in 
ridicule of fascination, it is nevertheless true that birds, and even quadrupeds, are, under certain 
circumstances, unable to retire from the presence of certain of their enemies ; and, what is even 
more extraordinary, unable to resist the propensity to advance from a situation of actual 
safety into one of the most imminent danger. This I have often seen exemplified in the case 
of birds and snakes ; and I have heard of instances equally curious, in which Antelopes and 
other quadrupeds, have been so bewildered by the sudden appearance of Crocodiles, and by 
the grimaces and contortions they practised, as to be unable to fly or even move from the spot, 
towards which they were approaching to seize them. 
