The difference in the number of spawned eggs between animals of similar size and mean numbers of spawned eggs in consecutive trials decreased the longer animals were held in captivity before spawning. The hatch rate of eggs was reduced significantly for broodstock held for more than one month. Hatch rate and numbers of spawned eggs are important indicators of egg viability of broodstock maintained in captivity for an extended period. Communicated by Vicki Pearse Editor, Invertebrate Biology Abstract. The ciliary band of the auricularia larva runs along a series of ridges that project from the sides of the body.
Fragmentation results from a loss of ciliary band cells from the zones between the ridges.
The remaining fragments then reorient, elongate, and fuse to form the 5 circumferential bands of the doliolaria . The fate of the band cells lost during this process could not be determined with certainty, but they disappear after being sequestered beneath the epithelium for a time, probably through histolysis. Cell counts indicate that significant numbers of cells are also lost from the ridges. Normal swimming ceases just before transformation begins, probably because the nerve supply to all or parts of the band is disrupted, and this may play a role in initiating morphogenesis. While ossicles were not observed in auricularia and doliolaria larvae, which instead possessed elastic balls, ossicles were present in late pentactulae .