15 90 Proceedings of the Royal Irisli Academy. 



III.— THE ALGAL FLOEA. 



1. — Systematic List of the Floba. 1 



The subjoined list includes all species, and the most noteworthy varieties 

 found during the Survey, with the addition, in brackets, of those recorded 

 previously by other observers. Notes on habitat are given when of interest, 

 and local distribution is indicated, except where the species is of general 

 occurrence. Critical notes on the list are given later (pp. 102 et seq.). 



The classification adopted is that of Batters' " Catalogue of British Marine 

 Algae" (1902), except for the group Melobesieae, for which Lemoine's scheme 

 ('10) has been used. The nomenclature also of that catalogue has been 

 followed, except in the case of certain old names revived by Batters. When these 

 names appeared invalid or doubtful, the usual and more familiar nomenclature 

 has been employed. Critical work naturally has necessitated a few additional 

 name-changes. 



The following signs and abbreviations are used : — 



* = new to Ireland. r = rare, 



f = new to British Isles. /= frequent. 



CI = Clare Island. c = common. 



CB = Clew Bay. ah = abundant. 



AS = Achill Sound. / = local. 



BB = Bellacragher Bay. y = young. 



CYANOPHYCEAE. 



COCCOGONEAE. 



Chroococcus turgidus Naeg. — CI, CB, /. Isolated specimens on various algae. 

 '"■'Aphanocapsa pallida Sabcnh. — CI, CB,/. 

 'Dermocarpa violacea Cm. — CI, CB,/. On various filamentous algae. 



Pleurocapsa fuliginosa Hauck. — CT r. On bare rocks near high-water line. 

 * amethystina Bosenv. — CI, CB,/. On Bhodochorton florididum and Corallina. 



Hyella caespitosa Born, ct Flah. — CB/. 

 HORMOGONEAE. 



Spiral ina subsalsa Oersted. — CI, CB,/. 



var. Oceania Gom. — CI r. On Halichond ria panicea. 

 *Oscillaria margaritifera Kiitz. — CI r. 

 nigro-viridis Thw. — Olr. 



1 The additions to the Irisli list are calculated from a revised and annotated copy of 

 Mr. J. Adams' "Synopsis." With regard to the Cyanophyceae, several species, which do not 

 figure in the marine section of the Synopsis, have been previously recorded from Ireland, but 

 from fresh-water or brackish localities. These were listed by Mr. Adams in the fresh- water 

 section. 



