SEA FISHERIES LABORATORY. 135 
no doubt being that such a long time had elapsed since 
the animal’s last opportunity of feeding that the contents 
of the stomach had been digested and had passed on. 
Consequently we found it important, in enquiries into 
the food, to state that, if the specimens cannot be exam- 
ined as soon as collected, they should be killed at once so 
as to stop digestion. 
The food of the Cockles examined in the laboratory 
consisted of spores and other young stages of lower 
Alge, filamentous Alge, fragments, and other vegetable 
debris, Diatoms, Foraminifera, Sponge spicules, fragments 
of minute Crustacean appendages, such as Copepoda, and 
of the larval stages of higher Crustacea, all mixed with 
sand grains. 
We have found that most cockles sent to the laboratory 
are infested by the minute Copepod, Lichomolgus agilis, 
recently described by Mr. Scott, but there is no reason to 
think that this commensal is in any way injurious to 
the cockle. There is also a similar Copepod in the 
mussel. Although there are five species* of cockle (the 
genus Cardiwm) which are found in this neighbourhood, 
still all the cockles sent to market belong to the one 
common species C. edule. Some of the men speak ot 
more than one kind, and of a smaller species, but although 
specimens from different beds may vary a little, in size, 
and colour, and thickness of shell, all that have been sent 
to the laboratory for examination, both large and small, 
are C. edule. Some specimens which were sent by Mr. 
Dawson on April 8th from one of the Morecambe Bay 
beds are very brown on the outsides of the shell and even 
along the inner edge of the valves and over part of the 
mantle lobes and siphons. We found that this staining is 
due to a deposit of amorphous oxide of iron, caused 
* See Fauna of Liverpool Bay, vols, I, and III. 
