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FISHES. 
The tongue varies in different tribes; it is fleshy in some, 
and osseous in others, so that its sense of taste must be very 
obtuse. In the latter case it is frequently provided with teeth, 
or corneous papillae. The body being covered with scales must 
also prevent much sensibility to touch. This sense is probably 
supplied in some families by the fleshy filamentous process. 
There is great variety in the construction of the teeth of 
fishes; while some genera are entirely destitute of them. Some 
species have them placed either in the jaws, the palate, the 
tongue, or the gullet; while others have them all at one time. 
The stomach is generally simple, with a short intestinal canal. 
The sexes are distinguished by the male having a milt, and 
the female a roe. The latter is composed of a multitude of 
eggs, which the female deposits in some appropriate place, and 
leaves them to develope without her aid, or even afterwards car¬ 
ing for them. They are impregnated or imbued with the vivi¬ 
fying principle by the male, after their extrusion from the 
female. 
The fecundity of fishes is very remarkable. In the roe of a 
cod Lieuenhoek found 3,686,760 eggs; that of a flounder con¬ 
tained 1,357,400. 
Fishes are long-lived animals, although we are yet but im¬ 
perfectly acquainted with the comparative longevity of the dif¬ 
ferent races. We have authenticated accounts of a pike having 
been known to live 260 years, and of a carp which was 200 
years old. This, no doubt, depends upon the density of the 
medium in which they exist, and their being less liable to the 
influence of atmospheric change of temperature. 
There have been many attempts at the classification of fishes, 
both by artificial systems and also from natural arrangements, 
but that of Cuvier seems the best which has yet been adopted. 
It is that system which we intend to follow. 
Cuvier divides all fishes into two sub-classes, namely: — 
SUB-CLASS I.—CARTILAGINOUS FISHES. 
It consists of three orders:— 
Order I. Cyclostomi.— II. Selachii.—A nd, III. Sturi- 
ONF.S. 
