429 
Tapes pullastra, Ostrea edulis, fragments of Coi'allina, and stoues 
of various sizes have frequently heen observed drifting in the tide- 
ways attached to the roots of C/iorda jilum and various species of 
Fucus^'". 
To prove that sea-weed may sometimes transport rather heavy 
things the following observation eau be qiioted (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 
Fueus serratus being swept away to sea by the ebbing tide. On 
flirther examination I found that this weed was siispended vertically 
in the water, the extremities of the fronds being just level with 
the calm surface of the sea. On securiug this mass of weed, I 
discovered a large stone attached to its base which weighed three 
quarters of a pouud“. With regard to the powers of flotation of 
some of the common seaweeds Vallentin records as results of his 
experiments that Halidrys siliquosa, Fueus nodosus and Fueus 
vesieulosus 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 faet that certain Lamelli- 
hranehiata, 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 determiniug the specifle 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- 
prisiug that the Danish East-Greeiiland Expedition of 1892 
in pelagic flshing secured one specimen, probably dead, of Mytilus 
edulis, 11““ in length (at K lat. 75° 37'^ W. 1. 6° 40'0. 
By another - species I noticed that some small dead 
specimens were able to float for several days, but in all probability 
