Clare island Survey — Marine Algae. 15 14? 



position in Ireland was very isolated, as it is entirely absent from the French 

 coasts. 



Specimens dredged by me in Clew Bay agreed well with Foslie's material 

 in the Dublin Museum, and Dr. Lemoine, to whom a fragment was sent, at 

 first passed it as that species. She, however, subsequently wrote that it bore 

 a striking resemblance to certain curious forms of L. incrustans, which had 

 been described from Guethary (Basses Pyrenees) by Heydrich, and further 

 examination showed that the structure agreed with L. incrustans rather than 

 with L. dentatum. As it was advisable to have the point finally settled, 

 further material was sent, including a specimen gathered by Foslie at 

 Eoundstone. Madame Lemoine kindly examined the samples anatomically, 

 and reported as follows : — 



" Je crois que tous ces Echantillons representent des formes de L. incrustans, 

 mais ce sont des formes anormales et curieuses. Ce sont des echantillons 

 ages qui se sont sEpares de leur substratum, et qui ont pris ce developpement 

 bizarre. Je me suis rendu compte aussi que l'algue etait agEe, parce que, 

 dans certains echantillons, en particulier dans celui de Clew Bay, le tissu se 

 desagrege apres decalcification, et il est impossible d'obtenir des coupes dans la 

 partie centrale. 



" Je ne suis pas arrivee a observer l'hypothalle, il aurait fallu abimer les 

 echantillons ; les lamelles libres ne sont constitutes que par le pErithalle. 

 J'ai etudie les deux Echantillons de Roundstone dans lesquels les dimensions 

 des cellules sont comparables a celles des cellules de L. incrustans. 



" Les echantillons de Roundstone appartiennent a une forme decrite par 

 Heydrich f. subdichotoma ['99, p. 225]. lis seraient plus jeunes que celui de 

 Clew Bay, qui, use et roule par les vagues, est tout a fait caracteristique de 

 la f. subdichotoma.'' 



A comparison of Heydrich's figures in the paper referred to (Berichte d. d. 

 bot. Ges. xvii, p. 221) shows that the Irish specimens agree in form with the 

 Mediterranean. The plant'is rare, but one or more knolls were collected on 

 each occasion that the Clew Bay or Roundstone " coral-banks " were dredged. 



Distribution. — L. incrustans : — British Isles (abundant), Faeroes, N. and W. 

 France, N. Spain, S. France, Italy, Dalmatia, Algeria, Morocco (Tangier and 

 Atlantic Coast), Canaries, S. Africa, Sandwich Islands. 



Var. subdichotomum. — Ireland (Clew Bay, Roundstone Bay), France 

 (Guethary, Banyuls). 



L. lichenoides Philippi. 



Lemoine ('11, p. 128) states that the anatomical structure of this species 

 is clearly that of Lithophyllum, and she therefore restores it to that genus. 



T2 



