The Fate of the Larval Organs in the Metamorphosis of Ostrea Edulis

Abstract

This is the first part of a study of the metamorphosis of the larva of the European flat oyster (Ostrea edulis) and deals with the fate of the larval velum, foot, adductor muscles and eyespots.The apical area of the larval velum forms the basis of the upper labial palps of the spat.The bulk of the velar tissue is broken up and cast off or eaten; the total dissolution of the velum being complete within 48 hr. of attachment.The larval foot after effecting attachment rapidly shrinks in size and disappears within 72 hr. of attachment. Partial loss of its tissues probably occurs.The statocysts persist in the spat.Following fixation the anterior adductor muscle rapidly degenerates.The so-called pigment spots of the larval oyster have the structure of eyes. During metamorphosis they degenerate rapidly in situ..