1 Q 2 Proceedings of the Royal Irish Academy. 



a number of records of Algae in general from near Westport were enumerated. 

 In 1906 I published a Paper 1 in conjunction with my son, Prof. G. S. West, 

 in which some records were given for the plankton occurring in Lough Keel 

 and Lough Acorrymore, Achill Island. A fair number of other records of 

 Desmids have been published in "British Desmidiaceae "■ for near Westport, 

 Castlebar, and Achill Island. From Clare Island itself and the Louisburgh 

 district I do not know of any previous records. 



The district is very rich in Algae ; 887 species, 254 varieties, and 46 

 forms have been collected, 3 and the investigation has resulted in extending 

 the known distribution of a large number of species, in adding 157 species 

 to the number of those already known for Ireland, in adding 19 species to 

 those already known for the British Isles, as well as adding to science C new 

 species, 27 varieties, and 7 forms. The new species are as follows : — 



Hormospora ellipsoidea Synechococcus minutus 



Ankistrodesmus Selenastrum Microcystis minutissima 



Eeinschiella eurvata Lyngbya cliarense 



As an example of a remarkable extension of range, one genus with its 

 single species was known previously only from one locality in Colorado. As 

 was anticipated for this class of plants, the species occurring on the island 

 are very much the same as those occurring in similar localities on the 

 adjacent mainland, the conditions being similar. The Algae are, as usual, 

 much scarcer on the Carboniferous limestone of tbe mainland than on other 

 rocks, from the natural comparative scarcity of wet places there, as well as 

 from the calciphobic character of many species. 



A few associations, out of many lists that were made, are enumerated : 

 these may be of some interest in these days of ecology-worship. It will be 

 noticed that the lists of species enumerated vary very considerably though 

 obtained from similar pools with similar surrounding influences. 



In all the bogs of this district, the gigantic thiobacterium Hillhousia 

 mirabilis was abundant. Another smaller species of this genus was also 

 frequent and is being investigated by the authors of the larger species ; the 

 smaller species has been found in England also. 



Although the list which follows is a fairly long one, with many localities, 



1 W. and G. S. West : A comparative study of the Plankton of some Irish Lakes. Trans. 

 Royal Irish Academy, vol. sxxiii, Sect. B, Part II, 1906. 



5 W. and G. S. West: British Desmidiaceae, vols, i, ii, iii, and iv. Bay Society, 1904, 1905, 

 1908, 1911. 



2 Made up as follows : — Fresh-water Algae, 769 species, 230 varieties, 40 forms : Marine 

 Diatoms, 118 species, 24 varieties, 6 forms. 



