404 PRISTEDT, SPONGES. 
seas. Not even the Dysidea, which is most common on the 
coasts of Norway and Great-Britain, is to be found here. 
The Chalinee are rather numerously represented, and 
especially is one species, identified by me as Chalina arbuscula, 
much spread. It is found as well in the European Arctic Sea 
and the Barent's Sea as in the Behring Sea. Still more com- 
mon than this species is the Cribrochalina variabilis, at least in 
the Siberian Arctic Ocean and the Beaufort's Sea. A few spe- 
cimens are from the limits of the Barent's Sea and the Kara Sea. 
The following group, very common in the arctic seas, is 
represented by numerous specimens. I am sorry to say that I 
have not been able to identify more than a few of them. The 
rest I have described as new species, though one or other 
may have been described before. 
The group BSuberitidine is represented by several species 
of which the Suberites montalbidus is the most common. It is 
found in all the seas west of Greenland as far as to the 
Behring Sea. The new species Tethya sibirica is obtained only 
in the Siberian Arctic Ocean and in the Beaufort's Sea. 
The following group, the Desmacidine, is represented by 
very numerous genera and species, the greater part of them 
being obtained in the seas west of Nova Zembla. Only a few 
are found east of cape 'Tscheljuskin. 
The Chalinopsinmide are very rare to the east of Nova 
Zembla. Only one species, the Clathria Lovéni, is obtaimed in 
the Siberian Arctic Ocean. 
The Geodia PBaretti, the only representative of the group 
Geodinide, is very numerous in the sea east of Greenland. 
The following abbreviations are used in this work: 
Sp. = expedition to Spitzbergen 1872—1873. 
N.S. = > >» Nova Zembla 1875. 
oj ARE > » Greenland 1883. 
Vi. = > of the »Vega» 1873—1880. 
The figures after the locality indicate the numbers of the 
stations. 
