37. Chap. 37.-The Fins Of Fish, And Their Mode Of Swimming.

CHAP. 37.—THE FINS OF FISH, AND THEIR MODE OF SWIMMING.

Hence it is that there is a difference,[1] also, in the fins of fish, which have been given them to serve in place of feet, none having more than four,[2] some two[3] only, and others none.[4] It is in Lake Fucinus[5] only that there is a fish found that has eight fins[6] for swimming. Those fishes which are long and slimy, have only two at most, such, for instance, as eels and congers: others, again, have none, such as the muræna, which is also without gills.[7] All these fish[8] make their way in the sea by an undulatory motion of the body, just as serpents do on land; on dry land, also, they are able to crawl along, and hence those of this nature are more long-lived than the others. Some of the flat-fish, also, have no fins, the pastinacæ,[9] for instance—for these swim broad-wise—those, also, which are known as the "soft" fish, such as the polypi, for their feet [10] serve them in stead of fins.

1. Aristotle, Hist. Anim. B. i. c. 6.

2. By this Pliny means, Cuvier says, only the symmetrical fins, or pairs of fins, the pectoral namely, which are in place of arms, and the ventral, which are instead of feet; of which, in fact, no fish has more than two pairs. Pliny does not include in this statement the dorsal, anal, and pectoral fins.

3. Eels and congers, for instance, which have but one pair.

4. Mursenæ and lampreys.

5. See B. iii. c. 17.

6. Cuvier thinks that there can be no question that he is speaking here of some mollusc or crustaceous animal.

7. Mureenæ, like eels, have gills, but the orifice, Cuvier says, is much smaller than in the eel, and the opercula, under the skin, are so small as to be hardly perceptible; indeed, so much so, that modern naturalists, Lacepède, for instance, have denied the fact of their existence.

8. Aristotle, De Part. Anim. B. iv. c. 13, and Hist. Anim. B. i. c, 6.

9. Or sting-ray. On the contrary, Cuvier says, the pastinaca, more than any other ray, has large pectoral fins, horizontally placed; but they adhere so closely to the body that they do not appear to be fins, unless closely examined.

10. By this name, Cuvier says, he calls the tentacles or feelers, which adhere to the head of the polypus, and which it uses equally for the purpose of swimming or crawling.