[Illustration: FIG. 149.—_Myrianida fasciata._ (From Malaquin.) The bright red markings of the living animal are here represented black. A, An asexual individual which has produced by budding from the zone (_z_) a chain of twenty-nine zooids, the oldest being labelled 1, the youngest 29. B, A ripe male zooid (_Polybostrichus_), with three tentacles and a pair of forked palps (_p_). There are five unaltered anterior segments. C, A ripe female zooid (_Sacconereis_) with the palps fused with the prostomium; _s_, the ventral brood pouch projecting on each side; _t_, tentacles.] A further development of this process of gemmiparity is exhibited by _Myrianida_. Here, there is no conversion of the hinder segments, but the normal preanal zone of proliferation gives rise to a large number of new segments. After a time the most anterior of these becomes a head, and thus a new zooid {281}is marked out. The zone of proliferation immediately in front of the new head now proceeds to form new segments, and a second zooid results. This process goes on till a considerable number of new worms have been formed at the tail of the original one, the oldest of these new ones being the most posterior, the youngest next the original "stock." In each zooid there is a zone of activity which adds to its number of segments, so that as we pass backwards the zooids increase in size. As many as twenty-nine such zooids may be formed in this way entirely by gemmation; and as each zooid becomes completed, genital organs make their appearance, and when these are ripe the zooid separates from the "colony" and leads an independent life. Here, as in _Autolytus_, the sexes are dimorphic, the male and female resembling those of that genus.