CHAP. 33.—GILLS AND SCALES.

Some fishes have numerous gills, others again single[1] ones, others double; it is by means of these that they discharge the water that has entered the mouth. A sign of old age[2] is the hardness of the scales, which are not alike in all. There are two lakes[3] of Italy at the foot of the Alps, called Larius and Verbanus, in which there are to be seen every year, at the rising of the Vergiliæ,[4] fish remarkable for the number of their scales, and the exceeding sharpness[5] of them, strongly resembling hob-nails[6] in appearance; these fish, however, are only to be seen during that month,[7] and no longer.

1. He must mean single ones, on each side of the head. Cuvier remarks, that the present passage is from a longer one in Aristotle, Hist. Anim. B. ii. c. 13, which, however, has come down to us in such a corrupt and fragmentary state, that it is totally unintelligible, or, at all events, does not correspond with modern experience. No fish, he says, is known to us that has one or two gills only. The Lophii of the system of Linnæus have three gills on each side, and the greater number of fish four, with a half one attached to the opercule. Some cartilaginous fish, again, have five or six, and the lampreys seven.

2. Aristotle, Hist. Anim. B. iii. c. 10.

3. The modern Lago di Como, and Lago Maggiore. See B. iii. c. 23.

4. See c. 20, as to the Vergiliæ.

5. Cuvier says, that in various species of the cyprinus, and more especially the rubellio, the Cyprinus rutilus of Linnæus, the roach, the Cyprinus jeses of Linnæus, and the bream, the Cyprinus brama of Linnæus, the male has, during the spawning season, little warts adhering to the skin and scales. This appearance has been remarked in especial on a species found in the lakes of Lombardy, known there as the "pigo," and similar to the roach of other countries. It is most probable that it is to this appearance that Pliny alludes. Rondelet, in his book on Fishes, gives a representation of it, and calls it "pigus," or "cyprinus clavatus;" but he wrongly, like Pliny, takes it to be a peculiar genus of fish.

6. Clavorum caligarium"—"nails for the caliga." This was a strong, heavy sandal, worn by the Roman soldiers. It was worn by the centurions, but not by the superior officers; and from the use of it, the common soldiers, including the centurions, were distinguished by the name of "caligati." The Emperor Caligula received that cognomen when a boy, in consequence of wearing the "caliga," and being inured to the life of a common soldier. The hob-nails with which the "caliga" was studded are men- tioned again in B. xxii. c. 46, and B. xxxiv. c. 41. Josephus tells us of the death of a Roman centurion, which was occasioned by these nails. As lie was running over the marble pavement of the temple of Jerusalem, his foot slipped, and he was unable to rise, upon which he was overpowered by the Jews, and slain. After the decline of the Roman empire, the caliga was no longer worn by the soldiers, but was assumed by the monks and recluses.

7. Dalechamps says, that in a similar manner, in the lake known by the name of Paladru, fish of most delicate flavour, called "umblæ," were to be taken in the month of December, and at no other part of the year; so, too, the alausæ, which are found in the Rhine, near Strasburg, in the month of May only, and at no other time.