Except in spore-producing plants, new individuals which result from agamogenesis usually do not separate from the parent-individuals until they have undergone considerable development, if not complete development. The agamogenetic offspring of those lowest organisms which develop centrally, do not, of course, pass beyond central structure; but the agamogenetic offspring of organisms which develop axially, commonly assume an axial structure before they become independent. The vegetal kingdom shows us this in the advanced organization of detached bulbils, and of buds that root themselves before separating. Of animals, the _Hydrozoa_, the _Trematoda_, and the _Salpæ_, present us with different kinds of agamogenesis, in all of which the new individuals are organized to a considerable extent before being cast off. This rule is not without exceptions, however. The statoblasts of the _Plumatella_ (which play the part of winter eggs), developed in an unspecialized part of the body, furnish a case of metagenesis in which centres of development, instead of axes, are detached; and in the above-described parthenogenesis of moths and bees, such centres are detached from an ovarium. When produced by gamogenesis, the new individuals become (in a morphological sense) independent of the parents while still in the shape of centres of development, rather than axes of development; and this even where the reverse is apparently the case. The fertilized germs of those inferior plants which are central, or multicentral, in their development, are of course thrown off as centres; and the same is usually the case even in those which are uniaxial or multiaxial. In the higher plants, of the two elements that go to the formation of the fertilized germ, the pollen-cell is absolutely separated from the parent-plant under the shape of a centre, and the egg-cell, though not absolutely separated from the parent, is still no longer subordinate to the organizing forces of the parent. So that when, after the egg-cell has been fertilized by matter from the pollen-tube, the development commences, it proceeds without parental control: the new individual, though remaining physically united with the old individual, becomes structurally and functionally separate: the old individual doing no more than supply materials. Throughout the animal kingdom, the new individuals produced by gamogenesis are obviously separated in the shape of centres of development wherever the reproduction is oviparous: the only conspicuous variation being in the quantity of nutritive matter bequeathed by the parent at the time of separation. And though, where the reproduction is viviparous, the process appears to be different, and in one sense is so, yet, intrinsically, it is the same. For in these cases the new individual really detaches itself from the parent while still only a centre of development; but instead of being finally cast off in this state it is