Clare Island Survey — Marine Algae. 16 145 



Rhododermis polystromatica Batters, in obs., Journ. Bot., 1896, p. 389 

 (B. clegans var. polystromatica Batters). 



The variety polystromatica is so distinct from Crouan's l J . clegans that it 

 certainly ought to be regarded as a distinct species. Batters himself proposed 

 the combination in 189G (I.e.) ; but in 1902 he (probably inadvertently) used 

 the older designation. 



Choreonema Thureti Schmitz. 

 A minute species, which requires to be carefully searched for. It has 

 been stated to be common in Ireland, and to occur on all three species of 

 Corallina ; but this is probably an error. On Clare Island it was found only 

 on C. squama ta (its usual host), although a large amount of C. officinalis was 

 carefully examined with a lens. The plant is also known to occur on 

 C. rubens. 



MELOBESIEAE. 



The material of this group, as noted above, was examined by Dr. M. 

 Lemoine, who kindly furnished critical observations on the specimens, and 

 also prepared a complete list of the species obtained, together with notes 

 on their distribution. In view of the confusion existing, the general 

 distribution of each species as supplied by her is published in the present 

 report. It will be noted that the nomenclature differs slightly from that 

 employed by Batters. 



Attention should also be drawn to the account given by Johnson and 

 Hensman ('99), where analyses of the Knockboy and Bantry Bay sand, 

 together with other details of local interest, are given. Since that date much 

 critical work has been done, and hence seven of the plants listed there as 

 distinct species are in the present report regarded as synonyms or varieties. 



Melobesia farinosa Lamx. 



Abundant on Zostera in Clew Bay, and found at all seasons. 

 Distribution. — General. 



M. zonalis Fosl. 



This minute species was dredged in Clew Bay (3-5 fathoms) in February, 

 May, and August, 1911, and is evidently frequent. It occurs on glass, 

 porcelain, and shells. M. zonalis belongs to the subgenus Pliostroma, the 

 species of which are characteristic by being polystromatic. 



Distribution. — England, Scotland, Ireland, N. France (Brest), Mediterranean 

 (Banyuls). 



R.I. A. PROC, VOL. XXXI. T 13 



