When Professor Nordenskiöld asked me to give a sketch 
of the forms and the distribution of arctic Hyperids, founded 
on the rich materials he had himself brought together during 
his different arctic expeditions, he thought it convenient at 
the same time that a comparison should be made with the 
corresponding forms of the antarctic region. In compliance 
to his request the present treatise has been elaborated as a 
first and far from complete contribution to the very interesting 
question of the relationship of these imperfectly known pelagic 
crustacea. 
The materials used for the elaboration of this paper are: 
1:o) The large collection of arctic and pelagic crustacea in 
the Zoological State Museum in Stockholm, most liberally 
placed at my disposal by Professor S. Lovén. 
2:0) 4 most valuable collection of Hyperids from the Uni- 
versity Museum at Copenhagen, with the utmost bene- 
volence entrusted to me for examination by Professor 
Japetus Steenstrup. and Professor Chr. FE. Luätken. 
sto) At Tic colceton. of uHyperids,, prinetpally from the 
southern Beas, collected by the too early deceased Cap- 
tain Georg von Schéele for the University Museum 
at Upsala, and kindly forwarded to me by Professor 
TNTe HOoNbBTTIb ere 
4:0) The collection of Hyperids from »Musée du Jardin des 
Plantes», in the most generous manner placed in my 
hands for comparison by Professor Alphonse Milne- 
Edwards. 
In my opinion the limits of the zoo-geographical regions 
must be taken more generally with regard to truly pelagic ani- 
mals than regarding the inhabitants of the depths and the 
shores. Therefore -I shall fix the southern limit of the arctic 
region at Lat. 60” N., and the northern limit of the antarctic 
region at Lat. 50? S. Certainly a part of the Gulfstream will 
Bil Mk 30 
