rows, the largest being external. The teeth are hollow to near the
apex. They are first attached by ligaments to prominences of the
thick alveolar margin, which ligaments become converted by the
ossific process into bony cylinders, corresponding in size with the
base of the tooth to which they are finally anchylosed. The teeth,
when shed, separate from these cylindrical bases, which are removed
by a subsequent process. The branchial teeth are arranged in small
groups on the summits of the short obtuse apophyses which project at
regular distances from the concave margin of the branchial arches.
The pharyngeal teeth resemble in form and arrangement those of the
jaws, but are smaller in size.
C H A P T E R V.
T E E T H O F C Y C L O I D F I S H E S .
LABROIDS.
47. The fishes included in the family Labroides of Cuvier, are
chiefly distinguished by the great size and strength of their pharyngeal
bones, of which there are two above and one below, all armed with
teeth which vary as to their forms in different groups or genera of
the family. Besides the pharyngeal teeth, which are adapted to give
the final comminution to the food, the fishes of the genus Labrus of
Linnaeus, or the “ Wrasses,” have teeth which are commonly well
developed and of a conical form on the intermaxillary and preman-
dibular bones, but none on the superior maxillaries, palatines, or
vomer.
In the sub-genus Clepticus, the pharyngeal teeth form, collectively,
small plates with a serrated margin. In the Clep. genizara
the superior pharyngeals support five rows of these saw-like plates,
which work upon a similar dental armature of the inferior pharyngeal
bone.
In the species of Chromis (Cuv.), and its subgenera Cychla,
Plesiops, and Malacanthus, the pharyngeal teeth are small, conical,
and arranged like the teeth of a comb. In Chromis proper and
Malacanthus, the anterior teeth of the intermaxillary and preman-
dibular bones are conical and of larger size ; behind these teeth,
which form a single row, are others of smaller size which resemble
those on the pharyngeal bones. In the Cychla there is a broad band
of villous teeth in each jaw.
In the genus Labrus (Cuvier), and most of its sub-genera,
the intermaxillary and premandibular teeth are arranged in one
or two rows, the outer ones presenting a conical form, slightly
recurved, with a few at the anterior and sometimes at the
posterior part of the dental series much longer than the rest. In
the genus Anampses, however, there are only two flat and somewhat
recurved teeth in each jaw, which project from the mouth; while
in the Cossyphus there are several minute granular teeth behind the
normal conical teeth of the jaws (figs. 1 and 2, PI. 45) ; and in
Ctenilabrus a band of villous teeth occurs behind the long anterior
conical maxillary teeth. In all these fishes the pharyngeal bones are
paved with hemispherical molars more or less flattened at the crown.
In the genus Lachnolaimus these teeth are confined to the posterior part
of the pharyngeals, the rest of the bones, as the name of the genus
implies, (1) being covered with a soft villous and vascular membrane.
In the more typical Labroids (Labrus, Cossyphus, and Julis), the
whole of the unattached surface of the pharyngeals is covered with
the molar teeth. (2) They vary in size and shape in different parts of
the pharyngeal bones ; some are angular instead of round, and the
smaller ones at the external angles ^sometimes present a conical form.
Each tooth is attached by the circumference of a slightly contracted
base to the margin of a shallow alveolus ; this margin is traversed by
fine vertical grooves, which are morticed into corresponding grooves
in the osseous margin of the base of the tooth. The floor of the
alveolus is a thin plate, perforated by numerous foramina, and does
not become anchylosed to the base of the tooth ; nor, indeed, does it
sustain any of the superincumbent pressure. The pharyngeal tooth,
when first in place, has its base excavated by a wide but shallow
(1) Xaxvrj lanugo, XaipoS, guttur. (2) PI. 45, figs. 3 and 4.