Clare Island Survey — Marine Algae. 16 133 



from that plant by its more slender filaments, which are composed of very 

 long cells, and by the occasional occurrence of sexual reproduction ; but 

 Rosenvinge remarks that he is not yet certain if the two are sufficiently 

 distinct to be kept apart. G. Thuretii appears to be a species of quiet waters, 

 being abundant in Clew Bay and Achill Sound, but only collected once on 

 Clare Island and then in pools at Portlea. It is especially plentiful on Zostera, 

 and is most conspicuous in late summer. 



C. endozoica Darb. 



A species of Alcyonidium washed ashore at Old Head was infected with a 

 Chantransia apparently referable to this species. Dr. Rosenvinge writes that 

 the parts are smaller, and that the fertile branches are less branched than in 

 Darbishire's plant. 



C. Alariae Jons. 

 Noted on several occasions on old fronds of Alaria which had been washed 

 ashore. It extends at times over a very considerable area of the lamina. 



Nemalion elminthoides (Velley) Batters. 



Velley's figure (in Withering, " Bot. Arrang.," ed. 2, vol. iii, p. 255, pi. xvii, 

 1792) is unmistakable, and it is confirmed by his specimen in Herb. Kew ; 

 his name, therefore, is rightly adopted by Batters in favour of the more familiar 

 A. lubricum, 1830. Velley's plants were collected at Portland Bill in (or 

 previous to) 1792, and it was interesting to observe in July, 1911, that the 

 plant still grows there in profusion. 



A more difficult matter is the separation of this species from the well- 

 known A. multifidum, described by Weber and Mohr in 1804. Ecological 

 observations on Clare Island (p. 37) and elsewhere increase the suspicion that 

 the two may be forms of one species ; but the point requires detailed study. 

 Interesting notes on the protonemoid stage of Nemalion and its biology are 

 given by Chester (Bot. Gaz., xxi, p. 340) and by Rosenvinge ('09, p. 144). 



Scinaia furcellata Bivona. 



Pound during the first year of the Survey only by J. Adams whilst 

 dredging off Mulranny in about 7 fathoms (August, 1909). Distribution in 

 Clew Bay probably local. 



Gelidium aculeatum Batt. (= G. corneitm var. aculeatum Grev.). 



Having no personal knowledge of the value of characters in Gelidium, I 

 follow Batters, who raises this plant to specific rank. It thus figures as an 



