Clare Island Survey. 



16 

 FRESH-WATER ALGAE, 



WITH A SUPPLEMENT OF MARINE DIATOMS. 



By WILLIAM WEST, F.L.S. 



Plates I.-II. 



Read Apjrii, 22. Published July 6, 1912. 



I made two special visits to the district dealt with by this Survey at Whitsun- 

 tide, 1910, and Whitsuntide, 191] , and collected a great deal of material. The 

 hundreds of gatherings were made from as varied habitats as possible, and 

 have since been worked out microscopically. Collecting was carried on over 

 the whole of the district, from Achill Island round by Curraun and Westport 

 to Louisburgh and Mweelrea ; inland as far as Castlebar ; and on Clare Island 

 itself. I have also utilized much other material that I had collected from 

 the district on several previous visits; and I have to thank the following 

 gentlemen for the opportunity of examining material collected by them : — 

 Messrs. Lancelot Bayly, A. D. Cotton, J. W. H. Johnson, E. LI. Praeger, 

 L. B. |Smyth, and G. H. Wailes. Mr. Wailes collected the material from 

 Inishturk, Inishbofin, and Caher Island ; these collections were all from 

 additional localities of much interest, and consequently have greatly enriched 

 this paper. The list of halophilous Diatoms has been very considerably 

 enhanced by means of the excellent material collected by Messrs. Smyth and 

 Cotton ; my own collections of marine material were limited and were not 

 made for the purpose of this Survey, as I was then unaware that I was to 

 be asked to examine and enumerate the marine Diatoms as well as the 

 fresh-water ones. 



Previous work in the district of this Survey has not been very considerable. 

 Archer's records are the earliest, but those from Mayo are few when com- 

 pared with his numerous observations from such counties as Dublin and 

 Wicklow. With regard to Diatoms, O'Meara did excellent work at the 

 greater part of Ireland; but I am not aware of any detailed work by anyone at 

 the district under consideration. In a Paper 1 I published twenty years ago, 



1 W. West : A Contribution to the Fresh-water .Mgae of W. Ireland. Journ. Linn. Soc, Bot., 

 xxix, 1S92. 



K.I.A, PROC, VOL. XXXI, A 16 



