16 160 Proceedings of the Royal Irish Academy. 



Bonne)naisonia_ hamifera. — Usually considered to be an alien species from 

 Japan (see p. 136). 



Dasya corymbifera. — A sub-littoral species. Known in England from 

 Dorset and the Channel Islands only. 



Bornetia secundijlora. — One of the most interesting additions. Head- 

 quarters in the Mediterranean (see p. 141). 



Seirospora hormoearpa. — Rare, but easily mistaken for other species ; 

 hence perhaps overlooked. 



Lithothamnium norvegicum. — Probably not uncommon in Ireland, but 

 regarded in the past as a variety of L. cajeareum. 



2. The Character of the Flora. 



The flora of Clare Island and Clew Bay resembles that of the south- 

 west of England, and is thus of a distinctly southern type. A number 

 of species occur which have not been found in Scotland, the east and south- 

 east of England, or Wales, though it must be remembered that much of the 

 shore of our east coast is unsuitable for a littoral flora, and that Wales has 

 been very little explored. Many species in the list are known only from the 

 south and west coasts of Ireland, but here again further exploration would 

 probably show a wider range. 



Notes as to Absentees. 



Before attempting to analyse the flora, a few remarks may be made on the 

 larger algae which were to be expected, but which were not met with during 

 the Survey. Of species known to occur in several parts of Ireland, the follow- 

 ing may have been overlooked, since they are rare or only occur sparsely : — 



Asperococcus compressus. Helminthocladia purpurea. 



Arthrocladia villosa. Gigartina acicularis. 



Aehinetospora pusilla. Daysa ocellata. 



Porphyra miniata. Pleonosporium Borreri. 



Bri/opsis Itypnoides is a more noticeable absentee, as when present it 

 is usually plentiful. The same may be said of Nitophyllum Gmelini and 

 N. Hilliae, both of which are known from counties Cork, Kerry, and Clare, 

 and also from Belfast Lough. Clew Bay would appear very suitable for their 

 growth, and as their season is a fairly long one, we must conclude that if 

 present they are very rare. In Plymouth Sound they are found in 

 abundance. Naccaria. Wiyyii also was not seen in any of the dredgings. 



