POISON APPARATUS 897 
some strain, which pushes it against a shoulder of the maxi]- 
lary bone, and tends to shut off the communication. 
“The injection of the venom, though to all appearance 
instantaneous, is a complicated process of several rapidly 
consecutive steps. Forcible voluntary closure of the jaws 
may always be, if desired, accompanied by a gush of the 
venom, owing to the arrangement of the muscles which effect 
such movement of the under jaw. These are the temporals, 
one of the three of which is situated in such relation to the 
poison-sac that its swelling in contraction presses upon the 
receptacle and squeezes out the fluid. The force of ejection 
is seen when the serpent, striking wildly, misses its aim; 
under such circumstances, the stream has been seen to spurt 
five or six feet. A blow given in anger is always accompanied 
by the spurt of venom, even when the fang fails to engage 
from whatever cause. But since this result does not follow 
upon mere closure of the mouth, it is probable that the two 
posterior temporals ordinarily effect this end, the more 
powerful action of the anterior temporal (the one which 
presses upon the poison-sac) being reserved for its special 
purpose. There is one very curious piece of mechanism to be 
noted here. Since the serpent always snaps its jaws together 
in delivering a blow, the points of the erected fangs would 
penetrate the under jaw itself in case they failed to engage 
with the object aimed at, were there no contrivance for pre- 
venting such disaster to the snake.- But there is a certain 
movement among the loose bones of the skull, perhaps not 
well made out, the result of which is to spread the points of 
the fangs apart in closure of the mouth, so that they clear 
the sides of the under jaw, instead of impinging upon it. 
“The complicated mechanism of the act of striking may 
be thus described:—The snake prepares for action by throw- 
ing itself into a number of superimposed coils, upon the mass 
of which the neck and a few inches more lie loosely curved, 
