r 
397 
records it from the Kara-Sea at a depth of 4 to 5 fms. That 
Mr. A. S. Jensen does not distrust Leche’s determination of this 
species, appears from the faet that it is from an earlier work of 
Leche^) that Mr. Jensen records the minimiim-depth of 40 fms. 
Thus there is no doubt that the sea-ice can reach the small 
depth where it lives. By the way the species is also recorded 
from other parts of the North Polar Basin at depths lesser than 
40 fms.: D’Urban^) mentions it from Bear Island at a depth 
of 25 fms. 
Secondly. When A. S. Jensen writes (1. c. 1900. p. 231) 
that the bottom of the sea between Jan Mayen and Iceland is 
filled up with dead shallow-water shells, one will easily get the 
impression that many hundreds of shells can be brought up in 
one single dredging. The quoted filled up, however, is not 
here to be taken literally. Mr. Jensen himself gives in a later 
pamphlet (1. c. 1902) — on given provocation — the information 
that the entire total of bivalve shallow-water shells (whole speci- 
mens, valves and determinable fragments) dredged at 14 stations 
at great depths between Jan Ma 3 ^en and Iceland was 63. In 
the same manner Priele and James A.Grieg state (1901 p. VI) 
that the entire number of shallow-water shells dredged during 
the Norwegian North-Atlantic Expedition at the two stations near 
Spitzbergen, at depths of 658 and 1333 fms., was 4 whole speci- 
mens, 15 valves, and several fragments. If it be taken into con- 
sideration that there at the named stations have been dredged more 
shallow-water shells than in any other part of the great depths of 
the Arctic sea it really appears that they do not oceur there in 
any abundance. 
It might well a priori be granted that shells might oceur 
among the stenes, gravel, and clay, which the floating ice carries 
W. Leche; Ofversigt ofver do af svenska Exped. insamladø Hafs- 
Mollusker etc. Kgl. Svenska Vet. Akad. Handl. Bd. 16. Stockholm 1878. 
S. M. D’Urban: The Zoology of Barents Sea. Ann. & Mag. Nat. 
Hist.' V. Ser. vol. VI. p. 265. 
