16 110 'Proceedings of the Royal Irish Academy. 



Urospora mirabilis Aresch. (= U. isogonci, Batt., '02, p. 14.) 

 This is the common species on Clare Island, only a few filaments doubtfully 

 referable to U. Wormskioldii being found in addition. The combination 

 proposed by Batters is questionable. No type of Conferva isogona Eng. Bot., 

 can be found ; and even if it could, it is improbable that its specific identity 

 could be recognized. The present plant was confused, in the older Irish 

 records, with Ulothrix flacca. 



Chaetomorpha litorea Harv. 

 Some small pieces of a Chaetomorpha collected at Mulranny appear to 

 belong to this species. The cells are 90-1 10 ft diam., and 1-1^ times as 

 long, and rather thick- walled. CarmichaePs Appiu gathering is not to be found 

 at Kew, and consequently Wyatt Exsicc, No. 220, must be regarded as the 

 type (see " Phyc. Brit.," PI. 333). It is doubtful if the species is not merely 

 a slender form of C. Ivn/wni.- 



C. linum Kiitz. 



Adams records G. I in am in ('08), but excludes it in ('10). In the second 

 paper it was regarded as a synonym of C. crassa : but as it is most unlikely 

 that all the Irish records of this common plant could be referable to that 

 species, I have not considered the Clew Bay gatherings as an addition to the 

 Irish flora. 



Ehizoclonium Kerneri Stockm. f. endozoica Wille. 



This addition to the flora of the British Isles appears to be not uncommon 

 in the west of Ireland, being found on several occasions during the Survey. 

 It is probably general on our shores, but its curious habitat — within the 

 tissues of the sponge Halichondria pcmicea — doubtless accounts for its being 

 overlooked. 



The first specimens were collected under the bridge at Achill Sound, 

 where patches of sponge of a deep green colour were noted. The latter were 

 found to contain algal filaments which agreed with Wille's description of 

 £. Kerneri f. endozoica that had just been published ('10, p. 291). Specimens 

 were forwarded to Dr. Wille, who confirmed the point, and added, " Es ist 

 doch sehr zweifelhaft ob die Alge zu B. Kerneri gehort, aber ich habe keine 

 sichere Vermehrungsorgane gefunden, unci mochte deshalb vorlaufig nicht 

 eine neue Gattung aufstellen." The alga was found later in sheets of 

 Halichondria in the caves near the lighthouse on Clare Island, and was noted 

 on both subsequent visits to Achill Sound, but in each case the specimens 

 were sterile, so that no fresh light on the affinities of the alga could be 

 gained. A curious bacteiium-like plant living in the sponge Terpios fugax is 

 recorded on p. 102 (foot-note). 



