THE FAUNA OF THE EXE ESTUAItY. 327 



littorea) and by hand picking. If this weed be allowed to grow, large 

 numbers of mussels die from suffocation, as the weed causes the sand 

 to silt up over them. This year (1901) the beds have suffered con- 

 siderably from this cause, probably on account of the large amount 

 of sunshine during the summer. The young mussels, about 1 mm. 

 long, were extremely abundant on the Entcromorpha on Bullhill 

 Ikmk (July 4th, 1901), on weed from the sponge ground off the 

 Clock Tower (July 9th, 1901), and at Orcombe Eocks (August 17th, 

 1901). A single filament of Enteromoiylia formed a resting-place for 

 a hundred or more young mussels. 



Kellia suborbiculakis {Montagu). One was taken in a crevice at 

 Orcombe Eocks. 



Diplodonta rotdndata {Montagu). One or two shells were taken 

 on Polesands, probably washed up from outside. It seems probable 

 that this species burrows very deeply in the sand, as we have never yet 

 taken it alive, although shells are not uncommon in places. 



Cardium aculeatum, Liiinccus. One valve of this species was found 

 on Polesands. 



Cardium echinatum, Linnceus. Three small living specimens and 

 many shells were taken on Polesands, the living ones being found just 

 below the surface. 



Cardium edule, Zinnccus. Occurs in profusion on Cocklesand, Bull- 

 hill Bank, and all along the west side of the estuary, from the Warren 

 upwards, wherever the ground is suitable. It is found either on the 

 surface or buried just below, and its collection for sale gives employ- 

 ment to a fair number of men and women, who are generally to be 

 seen at low tide armed with a "cock-rake," which is very like an 

 ordinary garden hoe, and a basket. The ground is simply raked over, 

 so that about half an inch to one inch of the surface is removed, and 

 the cockles which are uncovered are then picked up, 



Cardium norvegicum, Spengkr. Two living ones were obtained on 

 the Polesands, lying on the surface of the sand. They were probably 

 washed up from deeper water, the normal habitat of C. norvegicum. 



Venus chione, Linnceus. Valves only of this species were found on 

 the Polesands. 



Venus striatula, Linnceus. One living one on the Polesands buried 

 just below the surface. 



Tapes virginea {Linnwus). One very small one dredged on the 

 sponge ground off the Clock Tower (sta. 14b). 



Tapes pullastra {Montagu). A few shells only, on gravel between 

 Cock wood and Starcross (sta. 17). 



NEW SERIES, — VOL. VI. NO. 3. " 



