Mĕt'a-gĕn'e-sĭs, n.

n. [Gr. μετά, beyond, and γένεσις, production.] (Physiol.) The production of sexual individuals by non-sexual means, either directly or through intervening sexless generations; alternation of generation; polymorphism.

☞ During the non-sexual stages of production, large numbers of the succeeding forms are usually given off, as in the strobile. Thus, by a sort of budding, a series of individuals may be produced that are entirely without sexual distinction. Each of these may, in its turn, by subdivision or some other form of budding, give rise to a brood of sexless beings, which in turn produce individuals sexually marked, and from the eggs of these may re-appear the form with which the cycle of a sexual multiplication began. Metagenesis may be only a periodic form of reproduction in the animal, and has yet been observed only among invertebrates. Dana.