Four species of the genus
Cuthona Alder & Hancock are recorded for the first time. Two of these species are
Cuthona beta (Baba & Abe, 1964) and
C. alpha Baba & Hamatani, 1963: although the local specimens differ in some features, principally ceratal arrangement, length of the radula and colour, the differences are considered too slight to warrant separation. The other two are new, being distinguished by a combination of features:
C. scintillans sp. novo by the large size reached (24 mm), rhinophores, oral veil and number of ceratal rows (13), the rounded foot-angles, green diverticula and yellow surface pigmentation, and number of denticles on the largest radular teeth (9);
C. reflexa sp. novo by the simple colouration, short radula (30 teeth), terminal position of the cusp, a very short or no vagina and the renal opening above the anus. The name Tergipedidae ( = Cuthonidae) is given priority and its use reviewed. Three subfamilies are recognized viz . Cuthonellinae, Cuthoninae and Tergipedidinae, each founded on the division of the digestive gland. Thirteen genera are listed, but only seven are firmly established as being distinctive and belonging to the family; one of the remaining six,
Guyvalvoria Vayssiere, 1906, is certainly valid, but, because the ceratal arrangement is only superficially known, its place in the family could not be determined.