A new species of terebellid Polychaeta,
Scionella lornensis, is described from silty grounds on the west coast of Scotland. Its affinities with the genera
Scionella and
Pista are discussed and it is concluded that its closest relationship is with the former group, although it is shown that in the arrangement of the nephridia it corresponds with the latter.
A key to the species of
Scionella is given, with notes on
S. vinogradovi (Ushakov) and
S. japonica Moore, together with a key to the genera of the Terebellidae recorded from European waters.