394 , 
we examine only a part of the reports on this subject, we will find 
this interpretation not to be a true one. On the contrary, the dis- 
crepancy is very common, and this would have been still more evident 
if the writers of the molluscs from the great deep-sea expeditions: 
»Porcupine", ,,Challenger", ,,Travailleur", and ,,Talisman" 
in their statements about the bathymetrical distribution of the species, 
had distinguished between the living molluses and the dead shells. 
As a rule, however, they have omitted this. 
The tract for which the named occurrence of dead shallow- 
water shells at great depths has to be discussed in the first place 
is a part of the North Polar Basin, between Spitzbergen, Green- 
land, Iceland and Norway. 
In the excellent work of Prof. J.W. Brøgger: ,,Nivåforandringer 
i Kristianiagebetet" !) a description of this phenomenon is given, 
based on the investigations of the Norwegian North-Atlantic Expedi- 
tion and the Danish Ingolf-Expedition. An account of the pheno- 
menon has also been worked out by Mr. A. S. Jensen (1900 & 
1902)?) and — as far as the Investigations of the Norwegian 
North-Atlantic Expedition are concerned — by H. Friele (1879)2) 
and James A. Grieg & Friele (1901))). 
It appears from the reports that shallow-water shells as Peecten 
islandicus, Portlandia arctica, Cardium groenlandicum, Astarte bo- 
realis, Venus fluctuosa, Lyonsia arenosa, Mya truncata, Lacuna 
crassior, Margarita helieina, and Trophon chathratus have been 
found at depths of 656 and 1333 fms. off Bear Island and Spitz- 
ly Norges saoridk Undersøgelser Nr. 31. Kristiania 1900— 
7?) A. S. Jensen: I. Om Levninger af Grundtvandsdyr paa se ere en 
mellem Jan Mayen og Island. Vid. Medd. Naturh. For. Kjøbenhavn. 
1 . Fortegnelse over Skaller af bivalve Grundtvandsmollusker fra 
store Hanisb mellem Jan Mayen og Island. Vid. Medd. Naturh. Foren. 
Kjøbenhavn. 1902. 
3) H. Friele: ,,Catalog der auf der norwegischen Nordmeerexpedition 
bei Spitzbergen gefundenen Mollusken". Jahrb. Deutseh. Mal. Gesellsch. 
NE 18/9. 
i) H. Friele & James Å. Grieg: Mollusca. III. Den Norske Nord- 
havs Ekspedition. Zool. Christiania. 1901. 
