FISHES. < oden 
It was estimated at one time that one fifth of the popu- 
lation of Holland were devoted to this branch of indus- 
try alone. 
366. There have been various systems of classification 
proposed for the Fishes. Cuvier first divides them into 
those that have really bony skeletons, and those that 
have cartilaginous ones. He then divides the Osseous or 
bony fishes into two groups according to their fins, the 
first being spine-rayed, the second soft-rayed. The Car- 
tilaginous fishes he divides into two groups according to 
the arrangement of their gills, the fringes being free in 
the one, and being fixed in the other. Professor Agassiz 
classifies fishes according to the character of their scales, 
(making four orders. 
367. It would take us into too broad a field to go into 
the minute classification of fishes. I shall, therefore, in 
addition to what has already been presented, notice par- 
ticularly only a few of the most interesting of these 
animals. 
368. The Swordfish, Fig. 169, is found en every part 
Fig. 169.—The Swordfish. 
of the Mediterranean Sea. Its “sword” is an elongation 
of the upper jaw, of great strength. It uses it in trans- 
fixing its prey, running into shoals of fishes for this pur- 
pose. In the British Museum there is a piece of the 
bottom of a ship with a “sword” thrust entirely through 
it. The length of this fish is from twelve to fifteen feet. 
Another fish of about the same size has a similar projec- 
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