Page:Natural History, Mollusca.djvu/298



SOLEN.

The characters already enumerated belong pre-eminently to this, the principal genus; one or two others which are associated with it presenting them with less distinctness and with more approximation to the neigbouring families. The hinge is usually composed of a well-defined cardinal tooth and a lateral fulcrum in each valve. It varies in position. The hinder muscular impression is