Growth, reproduction and vertical migration in Clio pyramidata Linné, 1767 forma lanceolata (Lesueur, 1813), with notes on some other Cavoliniidae (Mollusca, Pteropoda)

Shell growth and size variation in populations of Diacria trispinosa Clio pyramidata, Cuvierina columnella, and Cavolinia gibbosa are studied. Attention is given to differences in the size variations of the four species caused by differences in their developmental biology. The reproductive cycle of Clio pyramidata forma lanceolata in the Bermuda Area is described and it is shown that there are more than one protandric hemaphrodite sexual cycles in one animal. The vertical migration of the four mentioned species is discussed.