Revision of the world species of Aplysia (Gastropoda, Opisthobrancia)

A review of the genus Aplysia and of the geographical distribution of its members has been made, based on the collections of the British Museum (Natural History) with comparative material from other national museums of Natural History, Marine Biological Stations and private collectors all over the world.The genus can be divided into five subgenera : Pruvotaplysia, the most primitive, with two species ; Neaplysia, North American, with probably only one species ; Varna nov., with more than twenty species ; Aplysia, with six species ; and Phycophila, of the Pacific, with one, possibly two species.Full descriptions of the species are given, and the following new species are described : cronullae, dura, gracilis, rehderi, reticulata, as well as a new variety, delli of A. nigra.Their affinities with one another and with other subfamilies of the Aplysiidae are discussed.I.