Náttúrufræðingurinn - 1966, Blaðsíða 98

92
NÁTTÚRU FRÆÐI NG U RINN
SUMMARY
Five Mollusca species new íor Iceland.
By Ingimar Óskarsson.
The author reports on 5 species of Mollusca new to the Icelandic fauna.
One of them belongs to the class Lamellibranchia, and 4 of them are of the
class Gastropoda including one species of the subclass Ophistobranchia. The
new species are as follows: Limaria (Lima) loscombi Sow., Emarginula crassa
anassa Dean, Teres teres Reeve, Liomesus ovum Turt., and Laona (Pliiline)
pruinosa Clark. All of these species have been collected from stomachs of had-
dock, which were caught at 20—120 metres depth. The shells look so fresh
that they undoubtedly were alive when they were devoured. The haddock in
which one specimen of Limaria loscombi was found was taken off Patreks-
Ijiirður. Only the right valve was undamaged, and its height was 19 mm.
Emarginula crassa anassa was obtained in one specimen only off Garðskagi
peninsula. The shell’s height was 12 mm and the greater diameter of its moutli
25 mm. Only 2 specimens of Teres teres have been found, one near Vestmanna-
eyjar Islands and the otlier in the bay Faxaflói. The length of the larger speci-
men is 11 mm. Liomesus ovum has been picked up in 18 specimens at a fair
number of localities off the south, west and northwest coasts of Iceland. The
largest of them (off Garðskagi) measured 30 mm in lieight. The shells of all
the Icelandic specimens are quite smooth. Contrary to this, they are said to
have spirally striate shells in description of tliis species from the coast of tlie
British Isles. The author has seen 2 specimens from tlie west coast of Ireland.
One of them was quite smootli like those from Iceland, but the other was
slightly striate. Tlierefore, this species apparently seems to vary as to the
sculpture of the shell. But such variations are not uncommon amidst species of
Buccinidae. Finally the aulhor mentions an Ophistobranchian species Laona
pruinosa. 11 specimens have been gathered in all from haddock taken off soutli
and southwest coasts of Iceland. The largest specimen is 4.5 mm in lengtli.
This species differs from other Icelandic Lobe-shells in having a distinct um-
bilical groove. The shells of 3 specimens from Hornafjörður have a tawny
band around the middle. The sculpture is irregular, longitudinal and spiral
striae, never chain-like. The author suggests that the 5 abovc-mentioned species
have as larvae been transported to Iceland by currents from the British Isles
at some time during the last 30—40 years.