OF FISHES IN GENERAL. 
137 
CHAP. XXIX. 
Of Fishes in general. — Of Cetaceous Fishes . — Hie Whale. 
— The Fin Fish. — The Narwhale, or Unicorn . — The 
Spermaceti Whale . — The Dolphin. — Grampus, Por- 
pesse, Sfc. 
The number of fish to which we have given names, and 
with the figure of which at least we are a little acquainted, 
is, according to Linnaeus, above four hundred. The majo- 
rity of these are confined to the sea, and would expire in 
the fresh water, though there are a few which annually swim 
up the rivers, to deposit their spawn. 
The chief instruments of a fish’s motion are the fins, 
which in some fish are more numerous than in others. The 
fish, in a state of repose, spreads all its fins, and seems to 
rest upon its pectoral * and ventral f fins near the bottom : 
if the fish folds up, for it has the power of folding either 
of its pectoral fins, it inclines to the same side; folding the 
right pectoral fin, its body inclines to the right side : folding 
the left fin, it inclines to that side in turn. When the fish 
desires to have a retrograde motion, striking with the pecto- 
ral fins, in a contrary direction, effectually produces it. If 
the fish desires to turn, a blow from the tail sends it about; 
hut if the tail strikes both ways, then the motion is pro- 
gressive. In pursuance of these observations, if the dor- 
sal If and the ventral lins be cut off, the fish reels to the right 
and left, and endeavours to supply its loss by keeping \he 
rest of its fins in constant employment. If the right pecto- 
ral fin be cut off, the fish leans to that side ; if the ventral 
fin on the same side be cut away, then it loses its equili- 
brium entirely. When the tail is cut off, the fish loses all 
'notion, and gives itself up to where the water impels it. 
i he senses of fishes are remarkably imperfect, and, indeed, 
that of sight is almost the only one which, in general, they 
'nay be truly said to possess. But this is, in some degree, 
compensated by their astonishing longevity, several species 
being known to live for more than an hundred years. Their 
longevity is still exceeded by their singular fecundity ; for 
a single cod, for instance, produces at a birth as many 
young ones as there are inhabitants in all Great Britain, 
"hove nine millions. The flounder produces at once above 
a "hllion, and the mackarel five hundred thousand. 
* t hose near the gills. + Tile belly fins. 
Vo I.. II 8 
$ Back fins. 
