Clare Island Survey — Marine Algae. 16 143 



It is chiefly distinguished by the corticating cells which grow upwards as 

 well as downwards from the nodes. Frequent in our district, being found 

 especially on the receptacles of Himanthalia on Clare Island. 

 Distrib ution. — Iceland , Faeroes. 



C. atlanticum Petersen. 

 A pretty little species, described by Petersen, from Iceland and the Faeroes. 

 On Clare Island a few specimens only were found. It apparently enjoys open 

 conditions, being collected on exposed rocks and on The Bills 



C. rubrum Ag. 



Dr. Petersen distinguishes the following forms in my material of this 

 perplexing species : — 



(a) prolifera-secundata, forms ti/pica, secundata, and irregularis. 



(b) pedicellata-virgata, f. irregularis. 



(c) subtypica-modificata , forms vera and irregularis. 



Abundant in great variety of form in all parts of our area. 



Gloiosiphonia capillaris Carm. 

 Found in several spots on the island during the first year of the Survey 

 only (July, 1909). Not present in the same spots in June, 1910, nor 

 August, 1911. 



Schizymenia Dubyi J. Ag. 



This is a distinctly southern plant, being known in England from Devon 

 and Cornwall only. In Ireland it has been recorded from Belfast Lough, but 

 not from the west or south. Several specimens were noted on Clare Island in 

 May 1911. 



Cruoria adhaerens J. Ag. 

 The distinctive features of C. adhaerens are not well known ; but relying 

 on the slides in the Batters collection in the British Museum, I have regarded 

 it as being characterized by the possession of short filaments which adhere 

 closely together. The individual cells also are short, but the tetraspores very 

 large. 



Cruoriella Dubyi Schm. 



C. Dubyi is the dominant species of incrusting algae in the shallow waters 

 of Clew Bay. It occurs abundantly on shells and stones at all seasons ; and, in 

 the inner parts of the bay, is found occasionally on the stipes of Laminaria 



