Page:The Zoologist, 4th series, vol 1 (1897).djvu/288

260 metaphorically) with the almighty dollar, or provide that its offspring shall be started in life as are the progeny of individuals whose dangers are fewer and whose resources are more abundant. If we apply this argument to the egg in question we may conclude that its enemies are comparatively few. The colour of the horny egg-capsule is usually either a delicate olive-green or a light brown, and well harmonizes with its surroundings. The egg is, relatively to the size of the parent, large, and the number deposited comparatively small; while the young on emergence are found to be an exact copy of the original, an almost perfect reproduction of the parent.

It seems somewhat curious that an egg possessing so many peculiarities should have been almost absolutely ignored by scientific men and naturalists generally, the more so as it is easily obtained and readily examined. So far as I have been able to find during a long and extensive period of study, Swammerdam, who wrote the ' Book of Nature,' is almost the only observer who has devoted any attention to the systematic study of these eggs; but the result of his researches was such that he writes:—"Among all the eggs of insects, of which I have various species in my collection, I know none worthy of greater attention."

The case which contains the fluid matter out of which the future worm is to be evolved is of a horny, not of a calcareous, substance. It reminds us of the egg-capsules of the dog-fish, found everywhere on the sea-coast. Here we have a hint too of the aquatic origin of Earthworms. Chemically it corresponds almost exactly with our nails, and with the hoofs and horns of animals. It is cuticular in origin, that is, the skin, and not the blood, the spleen, or any other internal organ or substance, is the agent in its formation.

Everyone knows that the finger-nails are most easily trimmed after the hands have been washed in warm water. The reason is plain. Horny substances absorb moisture, and swell in proportion to the amount taken up, at the same time becoming soft and pliable. It may here be observed that several species of Earthworm, besides the semiaquatic Allurus, go through the process of oviposition under water. I have not seen this fact recorded by other observers, but have often myself discovered worms