TOO The Irish Naturalist. April, 



THE LOUGH NEAGH PLANKTON. 



A Contribution to the Freshwater AIgra2 of the North of 

 Ireland. By W. West, F.L.S., and Prof. G. S. West. M.A., 

 F.Iv.S. Transactions of the Royal Irish Academy, vol. xxxii., section 

 B, part I. Pp. IOC, plates I.-III. 1902. 45. 

 In 1900 Mr. West was invited by the Fauna and Flora Committee to 

 undertake an examination of the aquatic flora of Lough Neagh. Accept- 

 ing this invitation, he visited the lake in May, 1900, and July, 1901. The 

 Bann Fisheries Company kindly placed a steam launch at his disposal, 

 which much facilitated the examination of the waters ; and the results of 

 his researches have now been issued. Excepting Mr. West's own recent 

 paper on Freshwater Algae of the West of Ireland^, no so important con- 

 tribution to our knowledge of the Irish freshwater flora has appeared 

 since O'Meara's well-known Report on the Irish Diatomac3e= in 1875. 

 The presentpaper enumerates 614 species, and 107 varieties and forms. 

 Of these some 24 species are unrecorded from the British Isles, while 12 

 more are new to science. The main interest of Mr. West's researches lies 

 in the fact that, apart from a short paper by Borge,^ his examination of 

 the central portions of Lough Neagh constitutes the first attempt at the 

 investigation of the Plankton of any of the larger British lakes. It is 

 interesting to find that a number of species which on the European 

 Continent are recognised as members of the Plankton-flora exclusively, 

 are also present in the Plankton of Lough Neagh. The total Plankton- 

 flora of Lough Neagh and its extension. Lough Beg, was found to number 

 92 species. These inhabitants of the open waters were much more abun- 

 dant in May than in July; the author suggests that collecting carried on 

 between August and October would probably add many interesting 

 species to his list. One of the most striking Desmids obtained was a 

 large Statirastnttn, which the authors describe as S. pelagicum. 



The algae of Donegal being quite unknown, three weeks were devoted 

 to the collection of material in that county in May and August, 1901, with 

 the result of making large additions to the list already compiled. A few 

 gatherings were also made in South Down, Louth, and Wicklow, Com- 

 menting generally on the Irish freshwater alga-flora, the authors point 

 out the curious apparent absence of the genus Vcuicheria, of which no 

 species has rewarded their search in any part of Ireland; also the great 

 rarity in the North of Euastrum insigne, a species of frequent occurrence 

 in most parts of the British Isles. Three Desmids — Micrasterias furcata^ 

 Staurastrum Arctiscon, and S. longispinum — are noted as peculiarly western 

 in their distribution, being known in our islands only from the Suowdon 

 range, the extreme north-west of Scotland, and in Ireland from Conne- 

 mara and Donegal. 



R. Lr.. P. 



J /<?«r;/. Linn. Soc, Bot, xxix., 103-216, pi. xviii-xxiv. 1892. 



2 Proc. R.I. A. (2) II. (Science), 235-425, pi. xxvi.-xxxiv. 1875. 



3 Susswasser-Plankton aus der Insel Mull. Botaniska Notiser, 1897. 



