Animal Life 
smooth or tuberculated teeth arranged so as to form a quincuncial 
pattern, and having a fine cutting-edge at the margins of the jaws 
(Fig. 11). Such an arrangement is, of course, admirably adapted to 
prevent the surface of the jaws being abraded by the rasping action 
of the coral as the fishes browse. There are no teeth on the palates 
of the parrot-fishes, so that the grinding-up of the fragments of coral 
broken off by the jaws (which are worked by muscles of unusual 
power) is entirely relegated to the pharyngeal teeth (Fig. 12). On 
the two upper pharyngeal bones of the majority of these fishes the 
Fig. 13. Pharyngeal : 3 ‘ ; 5 
Plate of Phyilodus, teeth form two pairs of longitudinal rows, which are convex from 
from the London 
x side to side. The two middle rows are in the shape of transversely 
Clay of Sheppey. 
elongated plates, set somewhat obliquely, and interlocking with one 
another in the middle line. The two outer rows, on the other hand, are small nodule- 
like teeth placed in the angles between the large plates. On the lower pharyngeal 
bone, which is undivided, the teeth occupy a much wider area, with a concave 
grinding surface to receive the convex upper millstone, as it may be called. All the 
teeth are comparatively small, with elliptical grinding surfaces, and form five or, six 
longitudinal series, which alternate with one another so as to form a quincuncially- 
arranged gvinding-plate of great power and efficiency. ; 
But it must not be supposed that fishes of the present day have anything like a 
monopoly in the matter of crushing pharyngeal teeth of this type. Their ancestors 
of the Upper Chalk and the Tendiom Clay were equally efficient in this respect, 
as is exemplified by the pharyngeal plates belonging to the extinct genera known as 
Pharyngodopilus and Phyllodus (Fig. 13), both of which were more or less intimately 
related to the wrasses. ‘The pharyngeal teeth of Phyllodus, of which the central ones 
are much larger than those of the marginal series, are remarkable for their extreme 
tenuity, and the rapidity with which they are shed and renewed. From the former 
character the genus derives its name of Phyllodws—leaf-tooth. 
Crushing-teeth of a widely different type are developed in the voracious Wolf-Fish 
(Anarrhichas), a gigantic relative of the diminutive blennies of our shores. The 
wolf-fish, like the wrasses, feeds largely on shelled molluscs, and in order to pick these 
off the rocks or the ocean-bed a certain number of the front teeth in both jaws are 
large, conical, and recurved. The rest of the dentition is, however, of a crushing type, 
and the bones of the hinder part of the jaws and of the palate are covered with large 
nodular teeth, recalling an old-fashioned pebble, or ‘cobble,’ pavement. The pharyngeal 
bones support much smaller conical and pointed teeth. It would seem, therefore, that 
the wolf-fish crushes the shells of its prey in its mouth instead of, as in the wrasses, 
in its throat. A further remarkable difference from the - 
latter fishes is to be found in the circumstance that the Zo 
new teeth of the wolf-fish come up alongside those in 
use, instead of replacing them from beneath. Several 
of the teeth in a wolf-fish’s mouth are generally broken 
or twisted out of place owing to the violent use to 
which they are subjected. 
Passing over a large number of groups of fishes, 
a few words must be devoted to the dentition of 
the Carp tribe. In the great majority of these fishes 
the jaws are devoid of teeth, which are restricted to 
the bones of the pharynx. The degree of development 
of these teeth probably depends to a great extent on 
the extent to which these fishes feed on vegetables, Fig. 14. Dentition of Wolf-Fish, 
