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 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. CHAPTER VII. FISHES VALUED FOR THE TABLE. At the present day, the first place in point of delicacy is given to the scarus, the only fish that is said to ruminate, and to feed on grass and not on other fish. It is mostly found in the Carpathian Sea, and never of its own accord passes Lectum, a promontory of Troas. Optatus Elipertius, the commander of the fleet under the Emperor Claudius, had this fish brought from that locality, and dispersed in various places off the coast between Ostia and the districts of Campania. During five years, the greatest care was taken that those which were caught should be returned to the sea; but since then they have been always found in great abundance off the shores of Italy, where formerly there were none to be taken. Thus has gluttony introduced these fish, to be a dainty within its reach, and added a new inhabitant to the seas; so that we ought to feel no surprise that foreign birds breed at Rome.