"[C]onsider the sea-hare Tethys, a shell-less, flabby sea-slug, actually a marine snail, which may be seen crawling about in tidal estuaries, somewhat resembling a rabbit crouched over. A California biologist estimated the number of eggs produced by a single animal during a single breeding season to be more than 478 million. And the adults sometimes occur by the hundred! Obviously all these eggs cannot mature, all this potential cannot, must not, become reality, else the ocean would soon be occupied exclusively by sea-hares. There would be no kindness in that, even for the sea-hares themselves, for in a few generations they would overflow the earth; there would be nothing for the rest of us to eat, and nothing for them unless they turned cannibal. On the average, probably no more than the biblical one or two attain full maturity. Somewhere along the way all the rest will have been eaten by predators whose life cycle is postulated upon the presence of abundant larvae of sea-hares and other forms as food—as all life itself is based on such a postulate."