178 PROCEEDINGS OF THE MALACOLOUICAL SOCIETY-. 



Though the attacks of fish might seem at first sight to afiord a 

 complete explanation of the relative paucity of moUuscan life on 

 this part of the Bank, I do not think that this actually is the case. 

 In the first place the poverty in species cannot be explained thus, 

 since many of the forms which are absent here are very abundant 

 elsewhere. In the second place one would have expected the area 

 surveyed by Leckenby and Marshall to have been similarly 

 depopulated, especially since one of their visits was in August. But 

 this was not the case. It seems to follow from the later fact that, in 

 addition to the depredation of fish, there is another factor contri- 

 buting to the relative sterility of the South-west Patch. This factor 

 may be the absence of organic debris, as already suggested, though 

 limiting factors of a physical, chemical, or even mechanical nature, 

 should not be disregarded. 



I have to acknowledge the courtesy of Dr. E. S. Russel, 

 Director, and Captain V. M. Davis, Assistant Naturalist, of the 

 Fisheries Laboratory, Lowestoft, who afforded me the opportunity 

 of this cruise. My thanks are also due to my colleagues, 

 Messrs. R. Kirkpatrick, W. Campbell Smith, and A. K. Totton, for 

 identifying specimens referred to in this report. 



