SEA-FISHERIES LABORATORY. B41 
smaller micro-crustacea suspended in the inhalent current 
which is continually passing between the mantle lobes. This 
current is set up by the cilia on the gills and palps, the 
water is filtered by means of the gills, and the microscopic 
matter is entangled in mucus and conducted to the mouth. 
The foot is a great mucus-secreting organ, and the 
labial palps and lips direct the food current to the mouth 
opening. 
When dredging on Pecten grounds, empty shells 
are frequently dredged up, which are neither old nor have 
the appearance of having been unoccupied for long. It is 
probable that starfish, together with the whelk, are 
accountable for some of these empty shells. A large dog 
whelk in Port Erin aquarium had killed and partially 
eaten a P. maavmus by getting the anterior end of its 
shell between the separated valves of Pecten, and then 
attacking the adductor muscie with its proboscis. 
Parasites are very scarce, no internal ones having 
been met with in any of the specimens sectioned. 
Lichomolgus maaimus (8) is, however, an interesting 
ectoparasitic copepod which may be obtained by washing 
in sea water the gills and mantle to which it adheres. It 
is of an orange colour, very like that of the gills, and, so 
far, has only been found in P. maavmus, from which the 
specific name is taken. 
Very often the shells of Pecten are bored through by 
Clione celata (a boring sponge). This ramifies extensively 
between the outer and inner layers of the shell, and gives 
off short shoots which pass outwards to the external and 
internal surfaces of the valves. At .the points where 
these tubes perforate the internal layer of the shell, the 
mantle secretes calcareous nodules of a dark grey or black 
colour. 
The outer surface of the upper valve forms, as one 
