168 Proceedings of the Royal Irish Academy. 



errors were bound to creep in. Some few species were included twice under 

 a different name, and in several cases a marine species was put among the 

 fresh-water species. These and some other errors are indicated iu a sepai-ate 

 section. Since the " Synopsis " was published a few additional sources of 

 information on the distribution of Algae iu Ireland have been discovered, of 

 which the most important is Gough's Paper on the " Plankton collected at 

 Irish Light Stations " Altogether new species to the number of 102 have 

 been added, and these are given in a separate section. In addition to new 

 species, a considerable number of new localities have been found for species 

 already listed in the " Synopsis." In some other cases the records of 

 distribution ia the Pro^-inces have been deleted, as the e\-idence in favour of 

 their retention was r^arded as insufficient. I have not thought it advisable 

 to give a list of these new or deleted localities in the present Paper. There 

 is, however, appended a revised census of species, gi^'ing the figures as they 

 stand at present. There is, finally, a list of additional Bibliographical items, 

 which, it is hoped, makes this section complete to the end of the year 1909. 



LIST OF SYNOXTilS. 



The name in the first column is that under which the species was 

 pre\iously recorded in Ireland, while the name in the second column is that 

 in iise at the present time. The symbol = means that the specimen is 

 identical with or is included under the name which follows. 



A.— FRESH-WATER SPECIES. 



I. Peridinieae. 

 Peridiniam 



alatom Garbini = P. Willei Huit/eldt-Kaas. 



II. — Diatomaceae. 

 Achnantbes 



flexella Breb. - Achnanthidium flexellum Br«6. 

 Achnanthidiam 



coarctatam Brcb. = Achnanthes coarctata Grun. 



lanceolatom Brdb. = Achnanthes lanceolata Grun. 



lineaie W. Sm. = Achnanthes linearis Grun. 



microcephalom Euts. - Achnanthes microcephala Grun. 

 Amphora 



aflSnis Kuts. = A. oralis Kiii:. 



minaiisiima W. Sm. = A. oralis Euts. 



