In like manner the ciliated gemmule from which was formed the "pluteus" of the Urchin, was dependent on the existence of a parent Urchin; the monadiform germ from which was developed the pentacrinus of the Feather-star, was originally hidden in the ovarian tubes of a parent Feather-Star: the infant _Serpula_ that deposited the first atoms of calcareous matter as a commenced tube, had begun its own existence in the body of a parent _Serpula_. It is true the evidence of the connexion between the germ and the parent is not in these low forms always patent to the eye; it is physiological. But it is not less conclusive to one who is able to appreciate its force. A physiologist is as sure that every germ, every ovum, in the Invertebrate animals, was produced by an animal of a former generation, as he is of the same fact in a Mammal, where his eye can see the scar of the umbilical cord. In many instances there is stronger, or rather more obvious and ordinarily appreciable, evidence of the link between the present and the past generation, than the physiological dependence. The world of Insects, which, from its immensity, and from the high organic rank of its members, affords us so exhaustless a mine of economical wonders,--is rich in examples to the point. A few of these I shall cite. The eggs of many Insects are not dropped anywhere, at random; for, as the newly-born young have limited powers of locomotion, and yet are in general able to subsist only on some particular kind of food, it is necessary that their birth should occur in the immediate proximity of such food: and therefore that the egg should be so placed. Now this circumstance would not be specially noteworthy if the locality selected for the deposition of the egg were the same as that in which the parent insect had been accustomed to find its own private enjoyments: we should reasonably say that the eggs were placed here, because the parents happened to be here. The case, however, is very different. We never find the egg of the Peacock Butterfly adhering to the leaf of a cabbage, nor that of the Garden White to the leaf of a nettle; but the nettle is invariably selected for the former, and a cruciferous plant for the latter. Yet there is nothing in the individual wants or likings of the Butterfly, in either case, to account for this. Both the one and the other flutter through the sunny air, alight to drink the water of some slushy pool, rest on the expanding flowers and probe them for nectar, or suck the exuding juices of an over-ripe fruit. But when did you ever see the gorgeous-eyed Peacock feeding on a nettle, or the White on a cabbage? Eagerly as they seek these plants, it is solely for the purpose of depositing their eggs where instinct teaches them their unborn progeny will find suitable food.