The ovarian tissue is composed of cell-strands which are thrown into loops, projecting into the body cavity of the female. One of the cells at the apex of each loop becomes enlarged and specialized, and gives rise to the ovum. Their subsequent fate, after detachment from the ovum, is not known. A considerable amount of yolk is present, rendering it heavy and opaque in the living condition. Two polar bodies are given off, and the first cleavage results in the formation of two unequal blastomeres.
Gastrulation is probably by epiboly.
An apical tuft forms within about eleven or twelve hours after insemination, and during the next 24 hours, elongated trochophores develop, which have a broad prototroch, a narrow telotroch, and red eyespots. These larvae continue to elongate, and by 60 hours have developed two or three sets of setae and a Y-shaped gut. Swimming is by a rotating movement. Report upon the Annelida Polychaeta of Beaufort, North Carolina. Reproductive organs of Diopatra.