mm the: year 1886, omtrusted by: Prof. Su Lovén with 
examination of the great collection of sponges in the State 
Museum; at »>tockrolm, IH found- that. many of the arctic 
sponges in that collection were unknown. I was therefore 
authorized by Prof. A. E. Nordenskiöld to describe the 
forms of those that had been obtained during the Swedish 
arctic expeditions. 
With regard to the classification, I have followed Prof. 
Oscar Schmidt as I did in my former treatise on sponges 
from the west-coast of Sweden, and with regard to the regions, 
I have, with a few exceptions, followed D:r C. Forsstrand”). 
If we first examine the Calcispongie, we find that there are 
but very few species representing this great group. No species 
have been obtained in the Siberian Ocean, and only two in 
the Beaufort's Sea. This fact may be owing to the imperfect 
exploration of these seas. Nor have any Calcispongie been 
gathered on the west-coast of Greenland. The other four are 
from the European Arctic Sea and the Barent's Sea, and one 
of them, the dSycandra utriculus, has also been found on the 
limits of the two regions, the European Arctic Sea, on the 
one side, and the Barent's Sea, on the other. The Sycandra 
arctica is the most common Calcispongia in the arctic seas. 
Of Hexactinellide two species have been found, which I 
have not been able to identify with any forms previously 
known. Both these species were dredged up to the west of 
the Kara Bea. 
There were no specimens of Lithistide captured during 
these expeditions. It is possible that no Lithistide are to be 
found in the most northerly parts of the arctic seas. 
Phe fourth group, the Halisarene, is represented by a 
single species. 
Of the fiftn group I could hardly expect to find any species, 
since this group, with few exceptions, belongs to more southern 
Fy Det arktiska hafsområdets djurgeografiska begränsning med ledning 
af skalkräftornas (crustacea malacostraca) utbredning, Upsala 1886. 
