429 
Tapes pullastra, Ostrea edulis, fragments of Corallina, and stones 
of various sizes have frequently been observed drifting in the tide- 
ways attached to the roots of Chorda filum and various species of 
Fucus", 
To prove that sea-weed may sometimes transport rather heavy 
things the following observation can be quoted (p. 418): ,,Early in 
the summer of last year while surface netting in my boat about 
three miles south of Falmouth harbour, I noticed a large mass of 
Fucus serratus being swept away to sea by the ebbing tide. On 
further examination I found that this weed was suspended vertically 
in the water, the extremities of the fronds being just level with 
the calm surface of the sea. . On securing this mass of weed, I 
discovered a large stone attached to its base which weighed three 
quarters of a pound". With regard to the powers of flotation of 
some of the common seaweeds Vallentin records as results of his 
experiments that Halidrys siliquosa, Fucus nodosus and Fucus 
vesiculosus are able to float for several weeks or even for months. 
Besides this transportation by means of floating ice and sea- 
weed I wish to call attention to the fact that certain Lamelli- 
branchiata, which have been cast ashore by the waves, and have 
taken air within their valves, are able to float. My friend Mr. Aug. 
Krogh and I noticed that this is the case with the common My- 
tilus edulis, while we were determining the specific gravity of certain 
Shells. In trying for how long time the specimens were able to 
float I observed that some floated only for a few minutes, some (living) 
for several hours, and a single one for more than twenty four hours. 
Such ashore-washed specimens may in high water time be carried 
away by the currents along the coasts. After this it is not sur- 
prising that the Danish East-Greenland Expedition of 1892 
in pelagic fishing secured one specimen, probably dead, of Mytilus 
edulis, 118% in length (at N. lat. 75” 87% W. L 6: 409). 
By another Mytilus-species I noticed that some small dead 
specimens were able to float for several days, but in all probability 
