Clare Island Survey — Marine Algae. 15 159 



British Isles from Clew Bay and Roundstone. It is doubtless dependent 

 upon a very special type of ground. 



(b) Additions to Ireland. — On examining the additions to the Irish llura 

 we find that a large proportion are minute or critical species which require 

 careful search and microscopic examination. In earlier days the west coast 

 list was well up to date, but in recent years, when algology in our islands 

 has been at a low ebb, the Irish seaweeds have been neglected, and the 

 numerous microscopic species discovered in other countries have not been 

 searched for in Ireland. Johnson added many to the Phoeophyceae some 

 twelve to fifteen years ago ; and Adams more recently has recorded additions 

 to various groups. Batters' Lambay list ('07) furnished twenty species new 

 to the Irish flora. 



In the present account the Myrionemaceae are specially well represented, 

 owing doubtless to a knowledge of their appearance in the field, gained 

 during four to five years monographic work on the group. With the 

 exception of the exceedingly rare Ascocijclus hispanicus, all the British species 

 were found during the Survey. Several require particularly close observation, 

 and have only been recorded once or twice previously for our islands. 



Amongst the more interesting plants new to Ireland, we may mention, 

 in addition to those already alluded to : — 



Cladophora prolifera. — A very distinct species collected on The Bills. 

 In the British Isles, known previously from Weymouth only. 



Monostroma orbiculatum. — A salt-marsh species found in beautiful condition 

 on Annagh Island. 



Capsosiphon aureolus. — Found at the mouths of fresh-water streams. 

 Hitherto known only from Scotland, but probably overlooked. 



Vaucheria coronata— Forming zones and broad associations, of a deep 

 green velvet appearance. Exceedingly abundant in Clew Bay. 



Ectocarpus clandestinus. — -Probably rather rare. Fine material gathered 

 on Clare Island in October, 1910. 



E. Holmesii. — Under the bridge at Achill Sound and in caves. Found on 

 several occasions with both kinds of fruit and in beautiful condition. 



E. microspongium. — Very inconspicuous, forming minute cushions on 

 crusts of Ralfsia. 



Mesogloia lanosa. — Dredged in Clew Bay in 1909. A most distinct species, 

 but rare and little known. 



Porphyra coccinea. — Probably short-lived. Known from four localities 

 only in the British Isles. 



Gelidi-um aculeatum, — Formerly regarded as a form of G. curaeum. 



