The present paper is the first part of the report on the Annelids brought home by the Ingolf expedition. Together with these, however, some other material of Annelids from Northern seas has been included. In this respect I shall name the rather considerable material brought home by several Danish naturalists on different expeditions to Greenland, Iceland and the Faroe Islands.
From East-Greenland originate the collections made by the Amdrup-Expedition, mainly due to the late zoologist, Mag. scient. Søren Jensen; also the then captain in the navy, Ryder and Cand. magist. Kruuse have brought home material from the East-coasts of Greenland.
Of special interest is the material from Davis Strait brought home by Ad. Jensen, now inspector at the zoological museum, on his cruises with the fishery investigation-ship "Tjalfe" 1908—1909; these collections as well as the material brought home by Dr. Nordmann and Cand. magist. Stephensen from their investigations in Greenland fjords have, together with the investigations of the Ingolf-Expedition, brought to light a fauna rather different from the usual Greenland litoral fauna with its well-known arctic forms — a fauna containing several boreal and more southern species not hitherto known from Greenland waters. The named investigations have shown that concerning the Annelids we have just the same facts in the distribution as have been established for other groups of animals, viz. Molluscs, Crustacea and Echinoderms: In Greenland waters we have to deal with so to say two different faunas of different origin, namely an exclusively arctic fauna mainly restricted to those tracts which have a negative bottom-temperature, and another mixed with species originating from southern regions and confined to those parts of Greenland seas and fjords with a positive bottom temperature.
From Iceland waters collections have been made by Dr. A. C. Johansen, Mag. scient. Otterstrøm, Mag. scient. A. Ditlevsen and Mag. scient. R. Hørring. From the named seas are also present Annelids collected by Ad. Jensen during a cruise with the Norwegian research-steamer Michael Sars in 1902.
A rather considerable material of Annelids was brought home from the Faroe Islands by Dr. Th. Mortensen in the year 1899. Also Mag. scient. R. Hørring, Mag. scient. A. Ditlevsen, Cand. magist. Gemzøe and Mag. scient. Otterstrøm have made collections at the coasts of the Faroe Islands.
In this connection I will add that the Danish investigation steamer ''Thor" has brought home a considerable material from the Faroes as well as from Iceland; also this material has been dealt with in this paper.
The present, first part of the report deals with the following families: Aphroditidae, Polynoïdae, Sigalionidae, Acoëtidae, Phyllodocidae and a new family which it has proved necessary to establish, the Otopsidae. These families are represented by 67 species in all.