435 
III. Dead shells of Littorina obtusata have been recorded from 
the Dogger-bank by W. Dunker & H. A. Meyer"), but any 
particulars regarding the shell-deposits in this place have not yet 
been set forth. 
IV. The banks and the submarine plateau at the Shetland 
Isles, West of Scotland and Ireland and South of Ire- 
land from 0 to ca. 300 fms. 
The molluscs preserved in British Museum, Natural History, 
from the ,,Lightning" and the ,,Porcupine" Expeditions convey the 
impression that the number of perfect shallow water shells from 
depths greater than those, at which the species live, is not in 
these areas very considerable. Very possible that their presence 
here may have been caused by currents and organisms. There is 
also a possibility that floating ice during one or various of Europe's 
temperature - minima may have contributed in carrying these shells 
off from the coasts. 
I wish to express my best thanks to Mr. Edg. A. Smith, 
F.Z.S. etc., for valuable suggestions with regard to several of the 
problems treated of here. 
1) W. Dunker & H. A. Meyer: Mollusca II in ,Jahresbericht der 
Commission zur wissenschaftlichen Untersuchung der deutschen Meere" 
Berlin 1875. 
3. October 1902. 
