the integuments of the aquatic animals are many in number. some are covered with a hide and hair, as the sea-calf and hippopotamus, for instance; others again, with a hide only, as the dolphin; others again, with a shell, as the turtle; others, with a coat as hard as a stone, like the oyster and other shell-fish; others, with a crust, such as the cray-fish; others, with a crust and spines, like the sea-urchin; others, with scales, as fishes in general; others, with a rough skin, as the squatina, the skin of which is used for polishing wood and ivory; others, with a soft skin, like the mur?na; and others with none at all, like the polypus.
of all aquatic animals the sea-calf is killed with the greatest difficulty, unless the head is cut off at once. it makes a noise which sounds like lowing, whence the name of “sea-calf.” the animals are susceptible, however, of training, and with their voice, as well as by gestures, can be taught to salute the public; when called by their name, they answer with a discordant kind of grunt.[132] no animal has a deeper sleep than this; on dry land it creeps along as though on feet, by the aid of what it uses as fins when in the sea. its skin, even when separated from the body, is said to retain a certain sensitive sympathy with the sea, and at the reflux of the tide, the hair on it always rises upright: in addition to which, it is said that there is in the right fin a certain soporiferous influence, and that, if placed under the head, it induces sleep.
there are one hundred and seventy-four species of fishes, exclusive of the crustacea, of which there are thirty kinds.[133]
tunnies are among the most remarkable for their size; we 137 have found one weighing as much as fifteen talents (1200 pounds), the breadth of its tail being five cubits and a palm. in some of the rivers, also, there are fish of no less size, such, for instance, as the silurus of the nile, the isox of the rhine, and the attilus of the po, which, naturally of an inactive nature, sometimes grows so fat as to weigh a thousand pounds, and when taken with a hook, attached to a chain, requires a yoke of oxen to draw it on land. an extremely small fish, which is known as the clupea, attaches itself, with a wonderful tenacity, to a certain vein in the throat of the attilus, and destroys it by its bite. the silurus carries devastation with it wherever it goes, attacks every living creature, and often drags beneath the water horses as they swim. it is also remarkable, that in the river main of germany, a fish that bears a very strong resemblance to the sea-pig, requires to be drawn out of the water by a yoke of oxen; and in the danube, it is taken with large hooks of iron. in the borysthenes, also, there is said to be a fish of enormous size, the flesh of which has no bones or spines in it, and is remarkable for its sweetness.
in the ganges, a river of india, there is a fish found which they call the platanista; it has the muzzle and the tail of the dolphin, and measures sixteen cubits in length. statius sebosus says, a thing that is marvellous in no small degree, that in the same river there are fishes found, called worms; these have two gills, and are sixty cubits in length; they are of an azure color, and have received their name from their peculiar conformation. these fish, he says, are of such enormous strength, that with their teeth they seize hold of the trunks of elephants that come to drink, and so drag them into the water.
the black sea is never entered by any animal that is noxious to fish, with the exception of the sea-calf and the small dolphin. on entering, the tunnies range along the shores to the right, and on departing, keep to those on the left; this is 138 supposed to arise from the fact that they have better sight with the right eye, their powers of vision with either being naturally very limited. in the channel of the thracian bosporus, by which the propontis is connected with the black sea, at the narrowest part of the straits which separate europe from asia, there is, near chalcedon, on the asiatic side, a rock of remarkable whiteness, the whole of which can be seen from the bottom of the sea. alarmed at the sudden appearance of this rock, the tunnies always hasten in great numbers, and with headlong impetuosity, towards the promontory of byzantium, which stands exactly opposite to it, and from this circumstance has received the name of the golden horn.[134] hence it is, that all the fishing is at byzantium, to the great loss of chalcedon, although it is only separated from it by a channel a mile in width. they wait, however, for the blowing of the north wind to leave the black sea with a favorable tide, and are never taken until they have entered the harbor of byzantium. these fish do not move about in winter; in whatever place they may happen to be surprised by it, there they pass the winter, till the time of the equinox.
manifesting a wonderful degree of delight, they will often accompany a vessel in full sail, and may be seen from the deck following it for hours, over a distance of several miles. if a fish-spear is thrown at them never so many times, they are not in the slightest degree alarmed at it. some writers call the tunnies which follow ships in this manner, by the name of pompili, or pilot-fish.
