Náttúrufræðingurinn - 1974, Blaðsíða 39

N ÁTTÚRUFRÆÐ INGURINN
161
S U M M A R Y
On some rare mollusk species from Iceland
by
Ingimar Óskarsson
Marine Research Institute, Reykjavik.
The author reports on the following four species of mollusks which are new
to the Icelandic fauna; Philbertia reticulata (Renier), Teretia amoena (Sars),
Velutina derugata (Becker) and Rissoella opalina (Jeffr.).
The first two species are collected from stomachs of liaddock which were
caught in Skjálfandaflói off North Iceland. Only one dead specimen of Phil-
bertia ancl four alive specimens of Teretia were found.
Velutina derugata has also been gathered from haddock, one specimen from
Skjálfandaflói and some off the west coast of Iceland. Some zoologists state
that this species should be considered as a variety of Velutina velutina (Möl-
ler). It was first found off Jan Mayen.
The fourth species Rissoella opalina has been found at two clifferent places.
Three specimens came from Skjálfandaflói taken from haddock stomachs and
one specimen was found on the shore in the neighbourhood of Kolbeinshaus,
Reykjavík.
The Icelandic specimens o£ Rissoella differ in size frorn those I have re-
ceived from the British Isles, where they were taken in the tidal zone. The
Icelandic specimens measure 3 mm in height but those from Britain only
2 mm.
Apart from tlie above mentioned gastropods the author discusses the appear-
ance and occurrence of Littorina littorea (L.) which has not yet been found
alive at Iceland ancl the taxonomic position of Littorina palliata (Say.) to-
gether with its remarkable and monstrous varieties.
The type specimens of the four above mentioned gastropods new to Iceland
are preserved in the shell-collection of Mr. Jóhannes Björnsson, Ytri-Tunga,
Tjörnes.
11