Lecture* viit. 
47 
()thers with the stomach; Some Fishes are totally 
destitute of the air-bladdery and such Fishes are 
observed to remain always at the bottom j as the 
whole tribe of what are termed flat-Fisb; If in 
such Fishes as are provided with an air-bladder, 
that organ be punctured, so as to let out its con- 
tained gas or particular aerial fluid, the Fish is 
unable to rise afterw^ards, but is obliged to remain 
continually at the bottom*. 
The teeth in Fish are extremely variotis in the 
different tribes, in some very large and strong, 
in others very small ; in some sharp, in others 
obtuse ; in some very numerous, and in others 
very few. Sometimes they are placed in the jaws, 
sometimes in the palate or the tonguey or even at 
the entrance of the stomaclu The eyes are in 
general large, and very much flattened, or far 
less convex than in quadrupeds and birds ; this 
structure being better calculated for giving them 
an easy passage through the water they inhabit : 
in return, the central part of the eye, or what is 
* It is observed by Cuvier, that sofne Fishes having remained 
for a considerable time near the surface of the water, under a 
hot Sun, have had their air-bladder so dilated by the heat com- 
municated to its contained gas, as to be unable suddenly to com- 
press it sufficiently to permit themselves to descend. 
