6 THÉEL, NORTHERN AND ARCTIC INVERTEBRATES. I. SIPUNCULIDS. 
undertakings of this kind, firstly because it is impracticable to do so, and secondly 
because it would serve no useful end. Thus, for instance, I consider it superfluous 
to refer to those numerous excursions among the islands in the Bohuslän Skärgård, 
embracing the island-elusters of Väderöarne, Koster etc., which the Marine Biological 
Station at Kristineberg has periodically organised and despatched since the year of 
its foundation 1877. TI also consider it needless to try to enumerate all such less 
extensive expeditions in the Stockholm Skärgård etc., as may have been undertaken 
during the period by Swedish naturalists, whether of higher or lower scientific rank. 
Nevertheless, the annexed historical survey is probably as complete a one as it is 
possible to give at this date, when many a journey, referred to below, has already 
passed out of the knowledge of naturalists of the present time. The survey is given 
chronologically. 
As has been said above, the collections of animals on which this report is based, 
belong mainly to the Swedish State Museum in Stockholm, but in order to be able 
to give a eritical account of all the forms of Gephyrea and their supposed relatives 
hitherto known from the Northern and Aretic Seas, it was indispensable also to get 
an opportunity of examining forms preserved in other Scandinavian museums, more 
especially those in the museum of Bergen, for that institution is in possession of 
many interesting species and types, which have been described by KOREN and DäA- 
NIELSSEN. That being so, it is ineumbent upon me here to state, that I am grate- 
fully indepted to my old friend, Dr. A. APPELLÖF, for having enabled me to 
reexamine those Bergen forms. Moreover, it affords me great pleasure in this place 
to express my sincere thanks to the Directors of the Museums in Upsala, Lund, 
Gothenburg, Christiania and Tromsö" and to some other zoologists likewise, for having 
given me the opportunity of studying the more or less extensive collections in their 
care. I am in that respect under great obligation to T. TULLBERG, D. BERGENDAL, 
I.. JÄGERSKIÖLD, R. COLLETT, SPARRE-SCHNREIDER, H. WALLENGREN, HJ. ÖSTERGREN 
and I. ARWIDSSON for assistance rendered. 
Here I take the opportunity of expressing my sincere thanks to GRorRG LILJE- 
VALL, the eminent artist, for the assistance with his excellent drawings. 
1 Phose specimens which belong to the Swedish State Museum in Stockholm are not followed by any 
specifications in their respective geographical notes. In other cases I have subjoined the name of the mu- 
seums, where each is preserved, making use of the following abbreviations: Mus. U. (Museum at Upsala), 
Mus. EL. (Museum at Lund), Mus. G. (Museum at Gothenburg), Mus. B. (Museum at Bergen), Mus. Chr. 
(Museum at Christiania) and Mus. Tr. (Museum at Tromsö). 
