A commensalic hydroid from wood-boring molluscs

Abstract

The occurrence of a commensalic hydroid of the genus Eugymnanthea has been noted in the wood-boring molluscs such as Nausitora hedleyi, Teredo furcifera and Martesia striata. Both the polyp and the young medusa are described. The mode of formation of the colony, movements of the hydroid and preliminary observations on the general ecology are noted and the nature of the relationship indicated.