Metamorphosis of the Larva of Ostrea edulis

Abstract

ALTHOUGH we now have a complete description of the fully-developed larva¹ of the European oyster (Ostrea edulis), we have as yet no account of the metamorphosis which takes place when the larva attaches itself and becomes the settled spat. The smallest spat yet described is that figured by Yonge² The shell of this individual measured 1.2 mm., whereas the shells of fully-developed larvæ before settlement average only 0.30 mm. There is therefore a considerable gap which requires to be bridged by the description of smaller spat.