Animal Dentition 291 
front teeth, there is a certain amount 
of variation in the number and size 
of the grimding-teeth according to the 
species. There is a constant and free 
succession of teeth in the sargus, as 
in the other members of the sea-bream 
tribe. Seaweed seems to form the food 
of these fishes. There are several 
other members of the tribe with sharp 
teeth in the front of the jaws and 
erimders behind, among them being the 
species of Pagrus and Pagellus. A 
difference in the form and number of 
the pharyngeal teeth occurs in each 
genus. 
Brief mention must be made of 
the dentition of the fishes known as 
Chetodonts, or bristle - tooths, among 
which is included the well-known Archer-Fish, remarkable for the habit of killing 
flies by darting a jet of water from its tube-like snout. In most of these fishes the 
teeth in the jaws resemble the hairs in a fine brush, and are of a soft, flexible, 
translucent texture; some genera have comparatively large teeth, while in others they 
ave more like velvet pile. 
The next fishes on my list are the beautifully-coloured Wrasses (Labrus, etc.), 
chiefly remarkable, so far as their dentition is concerned, for the great development 
of their pharyngeal teeth. In the jaws of these fishes the teeth are generally 
arranged in one or two rows, those of the outer row being conical and slightly 
curved, with a few at the front, and sometimes also at the hinder end of the series, 
considerably larger than the rest. The whole of the exposed surface of the 
pharyngeal bones of the throat is covered with a pavement of crushing-teeth (Fig. 10) 
varying somewhat in form, number and arrangement in the different members of the 
eroup, and likewise differing in shape in different parts of the bone in the same 
species. In most specimens of these bones it will be noticed that some of the sockets 
for the teeth are empty, and in the centre of a considerable number of them will 
be seen the summit of the crown of a new tooth, destined to replace the one which 
has been shed. Wrasses feed on molluscs, crustaceans, sea-urchins, etc., which are 
seized by means of the long front teeth, and ground to a pulp by the mill-hke 
action of the crushing pharyngeals. 
A still more powerful and complicated type of pharyngeal dentition is presented by 
the gorgeously-coloured Parrot-Fishes (Scarws, etc.) = 
Fig. 11. Jaws of Parrot-Fish, from the inner and outer aspects. 
of the tropical seas, which browse, as Sir R. Owen oy rains u 
graphically expresses, on the branches of the CST OL Hn} 
submarine forests of coral in a manner analogous 28% Sn wwe vale 
to that in which ruminants crop the land foliage. i i ce 4 ip ' i 
The coral branches beimg, however, of a stony oes . | iy 
A ie sy \ 
twigs and leaves of the forest, and we accord- 
ne find the jaws of these fishes modified into Mh | 
a beak sunnhune roughly that of a parrot in 
shape, but, in place of being sheathed in horn, 
encrusted with a highly-polished pavement of Tie, 12, 
3 o Hh “= 7) 
nature, require a much harder bite than do the ‘i BINS: 
Lower Pharyngeal Teeth of Parrot-Fish. 
