The specimen of
Hermaea described below was presented to one of us (T.E.T.) by Dr Eve C. Southward of the Marine Laboratory, Plymouth, whereas several
Polycera and
Favorinus specimens have been presented by the Warden and staff of the Dale Fort Field Centre, Pembrokeshire. Divers from the group working at the marine station at Carna in western Ireland have collected several specimens of
Polycera and
Favorinus for the other author (H.L.) who has also himself collected some specimens from Norway and Denmark. The drawings of the entire animals and some of the details have been prepared by Mr Gregory H. Brown. To all who have assisted us we extend our most grateful thanks.