Abstract
Most of the small northeastern Atlantic protobranchs classically referred to Leda, Portlandia, Yoldiella, Yoldia etc., are discussed and figured to facilitate identification. Yoldiella solidula sp.n. was previously included in Y. fraterna Verrjll & Bush, but is here considered a distinct, arctic species. The following new synonymies are made (the valid name mentioned first): Yoldiella lucida (Lovén, 1846) = Y. subangulata Verrill & Bush, 1898 = Y. iris Verrill & Bush, 1898. - Yoldiella nana (M. Sars, 1865) = Yoldiella fraterna Verrill & Bush, 1898 = Yoldiella inconspicua Verrill & Bush, 1898. - Yoldiella propinqua (Leche, 1878) = Yoldia pygmaea var. symmetrica Friele, 1878 = Portlandia persei Messjatsev, 1931. - Yoldiella messanensis (Seguenza, MS, Jeffreys, 1879) = Leda acuminata Jeffreys, 1873. - Yoldiella philippiana (Nyst, 1845) (neotype designated) = Yoldiella frigida mediterranea Nordsieck, 1974. - Megayoldia Verrill & Bush, 1987 = Microyoldia Verrill & Bush, 1987. - Megayoldia thraciaeformis (Storer, 1838) = Yoldia regularis Verrill, 1884 = Nucula groenlandica Posselt, 1898. - Neilonella Dall, 1881 = Pseudo-neilonella Laghi, 1986. - Neilonella striolata Brugnone, 1876 = Leda pusio, var. salicensis Seguenza, 1877 = Neilonella subovata Verrill & Bush, 1897 = Pseudoneilonella salicensis atlantica Laghi, 1986 = Pseudoneilonella montanaroe Laghi, 1986.
