42 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



submit them to a botanist for more precise identification. 

 No Amphidinium patches were present so far as I could see. 

 The variety of organisms present in the one little bay, the extra- 

 ordinary abundance in each patch, and the brightness of the 

 colour produced on the white sand were very striking, and 

 seemed worthy of note. 



" The colour was not in any of these cases due to the sand- 

 grains themselves, which are mostly clear quartz with, as usual, 

 a few black specks and some white shell fragments. Nor was 

 there apparently any fresh-water on the beach, and certainly 

 not any sewage or other source of impurity. It is a lonely, 

 sandy bay, inhabited only by sea-birds and seals, and the 

 nearest house is on the opposite side of the island at least four 

 miles away by the coast. The sea- water seemed very clear, 

 of salinity 26*5, and the sandy bottom could be seen from the 

 yacht anchored in five fathoms. 



" Diatom patches are no doubt abundant in many places ; 

 probably the simple green alga encrusting the sand-grains is 

 known to botanists, and I have certainly seen the pink organism 

 elsewhere. Probably other coloured patches due to micro- 

 organisms are present on many beaches. It would be interest- 

 ing to have them more thoroughly investigated — bio-chemically, 

 if possible — by someone living on the spot, and able to study 

 their changes day by day. — W. A. Herdman. S.Y. ' Runa,' 

 Sound of Islay, August 27th." 



I brought back samples of all these organisms, and 

 Professor Harvey Gibson, to whom I handed them over, 

 informs me that the pink one on the sand-grains is a Red Alga 

 belonging to the Schizophycese, viz., Microcystis elabens 

 (Meneghini), Kiitz. Professor Gibson tells me that the 

 identification has been confirmed by Professor Chodat, of 

 Geneva, who adds that it is, however, a very small form of the 

 species. This Microcystis has been found on the coast of 

 Norway, but is apparently a new record for British seas. 



