Náttúrufræðingurinn - 1973, Blaðsíða 125

NÁTTÚRUFRÆÐINGURINN
113
Wiebach, F. 1960: Bryozoa. Tierwcll Mitteleur. 1 (8): 1—76.
0kland, ]. 1964: The eutrophic lake Borrevatn (Norway) — an ecological study
on shore and bottom íauna with special reference to gastropods, including
a hydrographic survey. Folia lirnn. Scand. 13: 1—337.
— 1969: Ont mosdyr i ferskvann og en ny art for Norge. Fauna 21: 215—221.
S U M M A R Y
Three limnic invcrtebrate species new to Icelanð,
found in Mývatn in 1969
by Jon Fjeldsa,
Universitelets Zoologiske Museum, Köbenhavn, Denmark,
and Gunnar G. liaddum,
Zoologisk Museum, Universilet i Bergen, Bergen, Norway.
In ponds near Skútustadir numerous small colonies of Spongilla lacustris (L.)
(Porilera) were found, germinating from their gemmules on 7. July. Gem-
mulafes were lound in bottom samples from seven other places in the Mývatn
clistrict. Evidently, the sponges survive much of tlie year in resistant winter
buds in this climate.
One individual of the rare Theromyzon tnaculosum (Rathke) (Hirudinea)
was found in the thermal and alkaline bay Kálfstjörn on 5. May.
Plumatella fungosa (Pall.) (Ectoprocta) abounded under stones on thc
shoreline at Reykjahlid, a liighly eutropliic locality near warm springs and a
sewage outlet.
Identification, life history, distribution and ecology of these species is dis-
cussed. Hydrographic data are given from the collection localities. It is suggest-
ed that all three species were originally transported to Iceland by migrating
waterfowl; spongilla lacustris and Plumatella fungosa as resistant resting stages
adhcring to the feet and plumage of waterbirds, Theromyzon maculosum
wliile sucking blood in the respiratory tracts.
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