An orca has been seen even in the port of Ostia, where it was attacked by the Emperor Claudius. It was while he was constructing the harbour[2231] there that this orca came, attracted by some hides which, having been brought from Gaul, had happened to fall overboard[2232] there. By feeding upon these for several days it had quite glutted itself, having made for itself a channel in the shoaly water. Here, however, the sand was thrown up by the action of the wind to such an extent, that the creature found it quite impossible to turn round; and while in the act of pursuing its prey, it was propelled by the waves towards the shore, so that its back came to be perceived above the level of the water, very much resembling in appearance the keel of a vessel turned bottom upwards. Upon this, Cæsar ordered a great number of nets to be extended at the mouth of the harbour, from shore to shore, while he himself went there with the prætorian cohorts, and so afforded a spectacle to the Roman people; for boats assailed the monster, while the soldiers on board showered lances upon it. I myself saw one of the boats[2233] sunk by the water which the animal, as it respired, showered down upon it. CHAP. 6.—WHETHER FISHES RESPIRE, AND WHETHER THEY SLEEP. Balænæ have the mouth[2234] in the forehead; and hence it is that, as they swim on the surface of the water, they discharge vast showers of water in the air. (7.) It is universally agreed, however, that they respire, as do a very few other animals[2235] in the sea, which have lungs among the internal viscera; for without lungs it is generally supposed that no animal can breathe. Those, too, who are of this opinion are of opinion also that no fishes that have gills are so constituted as to inhale and exhale alternately, nor, in fact, many other kinds of animals even, which are entirely destitute of gills. This, I find, was the opinion of Aristotle,[2236] who, by his learned researches[2237] on the subject, has induced many others to be of the same way of thinking. I shall not, however, conceal the fact, that I for one do not by any means at once subscribe to this opinion, for it is very possible, if such be the will of Nature, that there may be other organs[2238] fitted for the purposes of respiration, and acting in the place of lungs; just as in many animals a different liquid altogether takes the place of blood.[2239] And who, in fact, can find any ground for surprise that the breath of life can penetrate the waters of the deep, when he sees that it is even exhaled[2240] from them? and when we find, too, that it can even enter the very depths of the earth, an element of so much greater density, a thing that is proved by the case of animals which always live under ground, the mole for instance? There are other weighty reasons as well, which induce me to be of opinion that all aquatic animals respire, conformably to their natural organization; for, in the first place, there has been often