A comparative study of the British species ofNuculaandNuculana

The survey of the sublittoral fauna of the Clyde Sea Area from 1949 onwards has shown that five species of the Protobranchiata are abundant throughout this region on a variety of substrata. Pelseneer (1891, 1899, 1911), Heath (1937), and Yonge (1939) have contributed much to the knowledge of the group as a whole, but little comparative work has been done at species level. Verrill & Bush (1897, 1898) studied the shell characters of the American Atlantic species. Moore (1931a, b) worked on the faecal pellets of the British Nuculidae and attempted to distinguish the species by this means, while Winckworth (1930,1931), mainly in the light of the latter work, attempted to clarify the nomenclature of these species. Winckworth (1932) lists six British species of the family Nuculidae:Nucula sulcataBronn,N. nucleus(Linné),N. hanleyiWinckworth,N. turgidaLeckenby & Marshall,N. mooreiWinckworth andN. tenuis(Montagu); and four species of the family Nuculanidae:Nuculana minuta(Müller),Yoldiella lucida(Loven),Y. tomliniWinckworth andPhaseolus pusillus(Jeffreys). All species ofNucula, exceptN. hanleyi, were taken from the Clyde Sea Area, although the latter species is included in the Clyde fauna list (Scott Elliot, Laurie & Murdoch, 1901). OnlyNuculana minutaof the Nuculanidae has been taken on the present survey.Yoldiella tomliniis included in the 1901 list but is noted as being ‘insufficiently attested’.Nucula hanleyiwas obtained from the Marine Station, Port Erin, butYoldiellaandPhaseoluswere unobtainable.