108 



On October 7th and 9th, after the disappearance of the main 

 patches, scrapings of sand from various parts of the foreshore 

 showed a small number of very active forms of Amphidinium, 

 together with a much larger number of Diatcans of the Navicula 

 type. 



I was able to confirm the observation of Professor Herdman 

 (Marine Biological Station, Port Erin, XXVI. Annual Report) as 

 to the considerable variation in shape of these Amphidinia from 

 the t3rpical form of Amphidinium operculatum, but no alternation 

 of Amphidinium and Diatoms in the same patches was observed. 



There was some evidence from laboratory experiments to show 

 that the Amphidinium sinks into the sand when covered with water, 

 but further observations are necessary before a definite conclusion 

 can be drawn. 



T. WHITEHEAD. 



