I shall first describe the dental peculiarities of the true Serpents,
and afterwards notice those of the Amphisbeenee in connexion with
the teeth of the Anguis and other serpentiform genera, which lead by
a series of close transitions to the Saurian order.
All true serpents subsist on animal matter and swallow their
food whole, whether they prey on living animals, as is the case in
almost every species, or feed on the eggs of birds as in the Deirodon
scaber, O., (Coluber scaber, Linn.)', :
With the exception of this and some congeneric species, in which
the teeth of the ordinary hones of the mouth are so minute as to have
been deemed wanting, the maxillary and premandibular bones in all
true Ophidians are formidably armed with sharp-pointed teeth ; there
is on each side the palate a row of similar teeth supported by the
palatine and pterygoid bones ; in the great Pythons and some species
of Boa the intermaxillary bone also supports teeth.
All the teeth, whatever he their position, present a simple conical
form, the cone being long, slender and terminated by an. acute apex,
and the tooth is either straight, or, more commonly, bent a little
beyond the base, or simply recurved, or with a slight sigmoid
inflection. The teeth are thus adapted for piercing, tearing, and
holding, and not for dividing or bruising. In some species certain
teeth are traversed by a longitudinal groove for conveying an acrid
saliva into the wounds which they inflict: in others two or more teeth
are longitudinally perforated for transmitting venom; such teeth are
called ‘poison-fangs’ and are always confined to the superiormaxillaries,
and are generally placed near the anterior extremity of those bones'
The serpents in which the teeth are all simple and solid, when the
pulp which occupies the basal cavity is calcified, will be first noticed.
92. Deirodon.—In the genus Deirodon(\) the teeth of the ordinary
bones of the mouth are so small as to be scarcely perceptible, and they
appear to be soon lost, so that it has been described as edentulous.
An acquaintance with the habits and food of this species has shown
how admirably this apparent defect is adapted to its well-being. Its
business is to restrain the undue increase of the smaller birds by
(I) Genus Anodon ofDr. A. Smith by whom the habits of the typical species have been well
elucidated. The name anodon had been previously applied to a genus of Bivalves
devouring their eggs. Now if the teeth had existed of the ordinary
form and proportions 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 exposed to instruments adapted for its perforation. These
instruments consist of the inferior spinous processes of the seven or
eight posterior cervical vertebrae, the extremities of which are capped
by a layer of hard cement, and penetrate the dorsal parietes of the
oesophagus ; they may be readily seen, even in very young subjects,
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 acid gastric juice.
93. Boa.—The simple teeth, ‘ dentes solidi’ as they are termed
in Erpetology, are of equal length in a few species of non-venomous
serpents; in the Pythons, Boas and Lycodons they are larger
towards the fore-part of the mouth; but in some Colubers and Tropi-
donotes the situation of the larger teeth is reversed. In Dryophis
and Psammophis there are a few very long teeth at the middle, and
again at the posterior part of the maxillary series. In Xenodon,
Coronella and many species of Homalopsis the posterior part of each
jaw is provided with a large and simple tooth, which is long and compressed
in the Xenodon.
In the Boa Constrictor, the teeth are slender, conical, suddenly
bent backwards and inwards above their base of attachment, with the
crown straight or very slightly curved, as in the posterior teeth. The
intermaxillary bone supports four small teeth; each superior maxillary
bone has eight much larger ones, which gradually decrease in size as
they are placed further back: there are eight or nine teeth of similar size
and proportions in each premandibular bone. These teeth are separated
by wide intervals, from which other teeth similar to those in