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of the face begins, and as the backward inclination of the 
teeth allows the food only to move in one direction, it is 
gradually drawn, by a constantly shifting of the hold on 
either side, into the throat. 
There is a South African Snake ( Deirodon ), the mouth 
of which is deprived of teeth, yet it is destined to feed on 
the eggs of birds. The apparent defect in this case has 
been pointed out by Professor Owen as a beautiful example 
of special contrivance. “ If,” observes that great physiolo- 
gist, “ the teeth had existed of the ordinary form and pro- 
portion in the maxillary and palatal regions, the egg would 
have been broken as soon as it was seized, and much of its 
nutritious contents would have escaped from the lipless 
mouth of the Snake in the act of deglutition; but owing 
to the almost edentulous state of the jaws, the egg glides 
along the expanded opening unbroken, and it is not until 
it has reached the gullet, and the closed mouth prevents 
any escape of the nutritious matter, that the shell is ex- 
posed to instruments adapted for its perforation. These 
instruments consist of the inferior spinous processes of the 
seven or eight posterior cervical vertebra;, the extremities 
of which are capped by a layer of hard cement, and pene- 
trate the dorsal (upper) parietes of the oesophagus; they 
may be readily seen even in very young subjects, and in 
the interior of that tube, in which their points are directed 
backwards. The shell being sawed open longitudinally by 
these vertebral teeth, the egg is crushed by the contractions 
of the gullet, and is carried to the stomach, where the shell 
is no doubt soon dissolved by the gastric juice.”* 
It might be expected that the ferocity of animals so 
* " Odontography.” 
