Clare Island Survey — Marine Algae. 15 131 



genus, and agree well with the description given by Zanardini. The filaments 

 are bright rose in colour, rather thick (25-35//, when sterile), and unbranched. 

 There is no true basal disk ; but a few horizontal cells are developed at 

 the base, and the filaments occur in tufts, as shown in Zanardini's figure ; 

 lateral mamillose protuberances as described by him are also present. The 

 specimens were found on Fucus (possibly attached to it), and agree well with 

 Haucke and Richter's Exsicc, No. 655 (also on Fucus), which Batters suggests 

 should be referred to E. investiens rather than E. ciliaris ('00, p. 374). 



E. Welwitschii Batters. 



This little-known and apparently very distinct species was found on limpet- 

 shells encrusted with Ralfsia verrucosa near low-water mark, in October, 1910. 

 The plant was originally described by Ruprecht as Cruoria (?) Welwitschii, and 

 the same specimens were later referred to by J. Agardh as Callithamnion 

 lepadicola. Batters ('02) removed the plant to its right genus, and made the 

 new combination Erythrotrichia Welwitschii. A portion of the Lisbon 

 gathering, collected by Welwitsch, exists at Kew, with which the Clare Island 

 specimens agree well. 



The species appears to be confined to the thalli of Ralfsiae, and is worthy 

 of further study. Hitherto it has been recorded in the British Isles from 

 Swanage only ; but it is probably widely distributed. When wet it is 

 inconspicuous ; but when the limpet-shells are becoming nearly dry, it shows 

 as a pale-pink felt. 



Porphyra coccinea J. Ag. 

 Somewhat rare, and not previously recorded for Ireland. I noted it, 

 however, in Co. Antrim in May, 1910 ; and a specimen collected by Miss 

 Hutchins, from Bantry Bay, was found unnamed in the Kew collections. 



P. umbilicalis Kiitz. 



Var. umbilicalis J. Ag. — The exposed Porphyra association, described on 

 p. 28, consists entirely of this form. 



Var. laciniata Thur. — Abundant throughout the area, being saxicolous or 

 epiphytic, and occurring in the littoral and upper sub-littoral regions, and 

 also in pools. It is the variety which forms the Porphyra association of 

 sheltered localities. 



Var. linearis Harv. (= P. linearis Grev. in Batters '02, p. 56 ; see 

 Rosenvinge, '09, p. 61). — Unless the growth of the plants be watched from 

 month to month, P. linearis Grev. would never be taken to be the same 

 species as P. umbilicalis Kiitz., especially as sporelings of the latter often 



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