#08
4th. Those whose ventral fins are behind the pectoral, as | İıe salıııon. , Besides these there are two kinds of cartilaginous fish, which differ from the others in having a cartilaginous instead of a bony skeleton: among the former of these is the sucker, and among the latter the shark. Rup. Is there any thing remarkable in the structure of fishes? Tut. Yes, the structure of fishes is entirely opposite to what is proper for the flying of birds. Different means must necessarily be applied to make birds and lishes luove upwards and downwards in their different elements. A smooth, long body, thick before, and gradually diminishing in bulk behind, is the best forumed for swimming. And of this form are fishes, Pup. How lo they breambe ? Tut. Not as we do for the air comes in through the luoush, and goes out through the gills; and by this tueans they live. - Pup. Have they senses ? Ти. The nostriis show they have the use of smelling. Their feeling too is finer than ours, because they sooner perceive the changes of the weather. Neither is their sense of sight prevented by the water, for which purpose their eyes are differently constructed from ours. Pup. Of what use are the scales of fishes?
