302 Mr George Traill on the 



The Marine Algce of the Orkney Islands. By 

 Geokge W. Traill. 



(Read 12th June 1890.) 



The Marine Algse of Orkney are so remarkable, both on 

 account of their beauty and rarity, that I trust the following 

 attempt to record all the known species with their principal 

 localities may meet with the approval of algologists. 



Excellent work was done many years ago by the Eev. 

 Charles Clouston ; and, subsequently, the Eev. John H. 

 PoUexfen was most successful in dredging as well as in 

 collecting between tide marks. Mrs Moffat, and her sister 

 Miss Watt of Skaill, and some others, are also deserving of 

 high commendation for their labours in different localities. 



The late Dr James M'Bain, E.N"., dredged during the 

 years 1842-46, while soundings were being taken for the 

 Admiralty Chart, and has added much to our knowledge of 

 the deep-water species. 



On Dr M' Bain's death I acquired his collection of Algae 

 and relative manuscript notes, from which I derived much 

 assistance in the preparation of the following record of 

 species. I am also greatly indebted to Mr Pollexfen for 

 much valuable and interesting information, and for his 

 kindness in carefully revising the list. 



During a visit to Orkney in 1887 I searched for a number 

 of unrecorded species, which it was thought should occur 

 there, and was fortunate in discovering the majority of 

 them. The more important are specially referred to in the 

 list ; and it will be observed that several are new to the 

 British marine flora. 



Though the list contains many more species than were 

 formerly known, the total still falls short of what might 

 have been expected, looking to the extent of coast, which, 

 according to the late Captain Thomas, E.N"., has an outline 

 of 573*7 miles. This may partly be accounted for by the 

 comparatively few good rock pools to be met with between 

 tide marks. 



The following may be mentioned as good localities : — 



The north shore of Westray ; Backaskaill Bay, Sanday ; 



