On The Primitive Significance of the Byssus in the Bivalvia and its Effects in Evolution

The byssal apparatus appears during post-larval life when its secretion permits brief attachment during metamorphosis when the animal assumes the form which fits it for life in the adult habitat. The byssus persists for continued temporary attachment in animals which may lose it in adult life, e.g. Mya arenaria , or in which it becomes an organ of permanent fixation, e.g. Mytilus edulis, Pododesmus macroschisma and Tridacna crocea