of the skull), arising from the outer margin of the anterior and
inferior moiety of the pharyngeal hone, passes inwards below the
pharynx and expands to meet its fellow at a strong median raphd.
This muscle, which is more especially developed in the barbel,
gudgeon, and those Cyprinoids which have the teeth formed for
piercing and lacerating, besides approximating the pharyngeal bones
at the median line, at the same time draws them forwards. The
antagonist muscle (c) arises from the descending spine of the basi-
occipital bone, and passing outwards and forwards, expands to be
inserted along the outer margin of the posterior half of the pharyngeal
bone ; this muscle while it draws back the pharyngeal bones, at the
same time, from the mode of attachment of the bones to the skull,
slightly divaricates them.
The teeth are attached to the inner side of the pharyngeal bones
by a confluence of their basis with the osseous substance. It might be
supposed that the food of the leather-mouthed fishes, as the Cyprinoids
without maxillary teeth are commonly termed, would be so
nearly the same, that the few teeth which were lodged in the fauces
would present much sameness of form ; but this is by no means the
case, as the selection of pharyngeal teeth from the Cyprinoid genera
figured in plate 57 demonstrates. The laniary type is best shown
in the barbel (fig. 1 & 2) and the molary type in the carp (fig. 6 & 7) ;
indeed, the latge lower 'pharyngeal tooth of this species exhibits,
before it is too much worn, the most complicated triturating surface
of any single tooth in the osseous fishes, and one which most closely
resembles that of the molars of certain herbivorous mammalia. (1)
The barbel (Barbus vulgaris), which feeds on slugs, worms and
small fishes, requires teeth so shaped as to pierce and lacerate the skin
of its prey, and to tear them into fragments capable of passing the
narrow oesophagus : in this species they accordingly are elongated, conical,
slightly and somewhat irregularly bent, arranged in three rows, and
increasing in number and size from the innermost to the outermost row;
the teeth in this row are generally five in number, separated by interspaces,
so as to interlock, when the pharyngeal bones are approximated,
as represented in plate 57, fig. 1 % the probe (a) shows their relative
(1) “ In the carp, the crowns of the teeth are observed to be so worn down as to have the
appearance of the crowns of the molar teeth of the hare,”—Yarrell, 1. c. Introduction, p. xix.
position to the entry of the oesophagus, and it may be seen how the
teeth must sift and lacerate the alimentary substances in their passage
through the pharynx.
In the Gudgeon, (Gobio), which feeds on worms, aquatic larvae
and small mollusca, the pharyngeal teeth are conical, slightly curved
at the extremity and arranged in two rows. In the Acanthopsis, the
pharyngeal teeth are sharp-pointed and placed in a single row. In the
Loach, {Colitis), which feeds on aquatic larvae and worms, the pharyngeal
teeth are slender and are chissel-shaped at the extremity. The
same scalpriform type is seen in the teeth of the genus Rhodeus.
In the genus Schizothorax lately established by the laborious Ichthyologist
I. J. Heckel for certain Cyprinoid Fishes from Cachmir,
the pharyngeal bones have three rows of teeth, two in the first, three
in the middle, and five in the third or posterior row, which last are the
strongest, all somewhat elongated, oblique, and with the extremity
slightly curved. The outer row of pharyngeal teeth are figured in situ,
on the right pharyngeal bone of the Schizothorax esocinus, Heck. (fig.
4) where they exhibit the shape most common in the genus : in Schizothorax
curvifrons, Heck, the pharyngeal teeth resemble long inverted
cones, the expanded, but originally pointed summits being soon worn
down so as to appear truncated.
In the Cyprinus Nasus, L., similarly shaped teeth are arranged
in a single row, nine in number, on each pharyngeal bone ; the inferior
ones being somewhat larger, with a narrow but flat triturating surface,
supported upon a slender pedicle.
In most of the species of Leuciscus, as the ide, the chub,(l) the
dobule, the dace, the minnow, and the roach, (fig. 4) the pharyngeal
teeth are subconical, slightly curved at the apex, and more or less
truncated, in an oblique direction: their food, which includes the softer
parts of aquatic herbs with worms and insects in different stages,
corresponds with this approximation to the molar type. Some species
of Leuciscus, however, as the L. Scardinius, Bonap. have the pharyngeal
teeth slightly dentated along the internal margin. The Leuciscus
erythrophthalmus has two rows of seven teeth on each pharyngeal bone ;
(1) A friend informs me that the larger chub take the spinning minnow and gudgeon freely,
and mash them out of all shape.
L 2