15 150 Proceedings of the Royal Irish Academy. 



L. Lenorm&ndi Fosl. 



Common in our area, forming an irregular band on damp and shady 

 rocks above L. incrustans (see p. 41). It is also very common on stones in 

 pools. 



Var. sublaevis Foslie. — A sub-littoral form. Not uncommon in Clew Bay 

 in 3-5 fathoms, on shells, especially Pecten. 



Var. squamulosa Foslie. — Frequent on the sides of dark caves. 



Distribution. — British Isles (common), Iceland, Faeroes, Norway, Sweden, 

 Baltic Sea, Denmark, Heligoland, N, "W., S. France, Mediterranean, Adriatic, 

 Morocco, Canary Islands, N. America (Atlantic Coast). 



L. Sonderi Hauck. 



Beautiful specimens belonging to form sublacvigata Foslie were dredged 

 from the " Helga " in Killary Bay. They formed a complete crust on the 

 shells of mussels which occurred abundantly in muddy places. Superficially 

 L. Sonderi strongly resembles L. Lenormandi; hut the structure is quite 

 distinct, the Blaments in the former separating easily from each other, whilst 

 in the latter the tissue is very compact (Foslie, '05, p. 24, Lemoine, '11, 

 pp. 84 and 97). L. Sonderi has not been recorded from England, but specimens 

 have been dredged by me at Plymouth in 1905 {teste Foslie). 



Distribution. — British Isles, Norway, Sweden, Denmark, Heligoland, 

 France. 



Epilithon membranaceum Heydr. 



(L. membranaceum Fosl., and L. corticiforme Fosl., Batt. in Cat., p. 97). 



It is satisfactory to find that authorities agree in regarding the two species 

 above cited as synonymous — a view held by several British algologists, though 

 Batters in 1902 kept them distinct. Dr. Lemoine did not deal with the plant 

 in her treatise on the Melobesieae ('11), but, in response to a special inquiry, 

 she wrote the following note : — " J'ai etudie avec soin dans les Herbiers les 

 E. corticiforme and E. membranaceum, je crois, comme d'ailleursc'etait l'opinion 

 de Foslie (1909, p. 75), qu'ils doivent etre reunis. II est probable qu'on a 

 designe sous le nom de corticiforme les thalles portant des conceptacles a 

 sporanges, et sous le nom de membranaceum ceux portant les conceptacles a 

 crystocarpes. L'aspect des deux sortes de conceptacles est tres different ; 

 les conceptacles a sporanges murs forment des sortes de petits crateres qui 

 laissent voir en leur centre le substratum ; ces crateres, tres nets sur 

 l'echantillon de Clew Bay fixe sur Bhodymenia, sont souvent confluents et 

 leur contour est ovale. Au contraire les conceptacles a cystocarpes sont 

 d'abord hemispheriques ; plus tard le toit tombe et il pent rester un petit trou 



