MARINE BIOLOGICAL STATION AT PORT ERIN. 71 



as Sponges and Ascidians, it is quite inadequate for active 

 animals such as Crustaceans and Fishes. These latter are, 

 however, able to seek out their food and are not dependent 

 on what they may filter or absorb from the sea- water. This 

 result accords well with our many observations on the irregu- 

 larity in the distribution of the plankton and the corresponding- 

 variations in the occurrence of the migratory fishes which may 

 be regarded as following and feeding upon the swarms of 

 planktonic organisms. 



Several of the reports during this period deal also with 

 observations on the minute life found in the sand and mud of 

 the sea-beach and its variations from time to time. Perhaps 

 the most remarkable observation in this respect was the 

 discovery that the Dinoflagellate A?nphidinium operculatum, 

 hitherto unknown in British seas, occurred from time to time 

 in enormous profusion on certain parts of the shore at Port 

 Erin. Although occasionally not present, it has continued to 

 reappear since the time of its first discovery in 1911 year by 

 year, and has been kept in quantity in the living condition in 

 our laboratory tanks for the benefit of the students. A full 

 account of the occurrence and the variations of this interesting- 

 organism will be found in the 25th and 26th Annual Reports. 

 Since its discovery at Port Erin it has been found in quantity 

 at such distant parts of the British Coast as Hoylake, Blacksod 

 Bay, Cullercoats and Iona. 



During some of the years preceding 191-1, when we had the 

 yachts " Ladybird " or " Runa " in commission during the 

 summer vacation, it seemed desirable to extend our planktonic 

 work northwards from the Irish Sea to the west coast of Scotia n I 

 and the Hebrides. Twelve such cruises were undertaken, seven 

 in the " Ladybird " and five in the " Rnna," and the results 

 are summarised in our Annual Reports for 1910 to 191;'. These 

 Scottish observations extend as far North as the Shetland 

 Islands and as far West as the open Atlantic to the South-West 



