and the males coming after swallow them up. Now these grains are fish, and from the grains which survive and are not swallowed, the fish grow which afterwards are bred up. Now those of the fish which are caught as they swim out to sea are found to be rubbed on the left side of the head, but those which are caught as they swim up again are rubbed on the right side. This happens to them because as they swim down to the sea they keep close to the land on the left side of the river, and again as they swim up they keep to the same side, approaching and touching the bank as much as they can, for fear doubtless of straying from their course by reason of the stream. When the Nile begins to swell, the hollow places of the land and the depressions by the side of the river first begin to fill, as the water soaks through from the river, and so soon as they become full of water, at once they are all filled with little fishes; and whence these are in all likelihood produced, I think that I perceive. In the preceding year, when the Nile goes down, the fish first lay eggs in the mud and then retire with the last of the retreating waters; and when the time comes round again, and the water once more comes over the land, from these eggs forthwith are produced the fishes of which I speak.