MARINE ALGyE, WITH A NOTE ON THE FRUCTIFICATION OF HALIMEDA. 165 



Dr. Herdman noted the presence of a few Algae on the Coral reef at Galle, but 

 was unable to bring any specimens. From what he says of them, and the rough 

 sketches, I should suggest that they might be the following species, but it must be 

 understood that this is mere suggestion : 



Caulerpa racemosa, var. uvifera, J. Ag., or C. sedoides, Aa. 



Halimeda tuna, Lam. 



Padina commersonii, Hat; v. 



Peyssonelia rubra, J. Ag. 



Caulerpa plumaris, Ac. 



Vanvoorstia spectabilis, Harv. 



Corallina sp. 



A characteristic of the above is that they were all observed on dead corals. 



A Caulerpa, which he noted as occurring on the Pearl banks, in the Gulf of 

 Manaar, but of which he has no specimen, would appear from his sketch to be 

 C. scalpel) 'iformis, Ag. Associated with it in quantity was a plant with ovate glossy 

 dark green leaves, which from the sketch appears to be Haloplula ovata, Gaudich. 

 They were growing through coarse quartz sand at a depth of 5 or G fathoms, about 

 10 miles from land. 



The field diaries kept by Professor Herdman and Mr. Hornell also contain 

 records of the following Algae from the Pearl banks : 



Halimeda, tuna, f. platydisca, ( 'hrysymenia uvaria, Udotea flabellata, Dictyurus 

 purpurascens, Zonaria lobata (?), Rally merda perforata, Laurcncia sp., Polysiphonia 

 sp., Corallina sp., Acetabularia sp., and "great quantities of Sargassum sp. both on 

 the bottom and floating on the surface." These are all forms which are quite likely 

 to have occurred. 



Dr. Herdman has asked me whether any comparison can be drawn between the 

 Algae of the Maldive and Laccadive Islands and those of Ceylon. The only collection 

 known from the former groups of islands was made by Mr. J. Stanley Gardiner, 

 and gathered on the coral reefs. It contained 23 species, chiefly of the Indian Ocean 

 type, more than half of which had previously been recorded from Ceylon. The actual 

 number of species common to that collection and Dr. Herdman's is only two : 

 Halimeda tuna, f. platydisca, and Galaxaura rugosa. 



Note on the Fructification of Halimeda. 



Many of the specimens of Halimeda gracilis, Harv., are in fruit, a condition of 

 this species which has never been noted or described. The only species of Halimeda 

 of which the sporangia have hitherto been observed, are H. tuna, Lam., H platydisca, 

 Decne, and H. macroloba, Decne. In a paper published in December, 1901 ('The 

 genus Halimeda, Siboga-Expeditie, Monographe LX.,' Leiden) 1 showed that 

 H. platydisca should be regarded as a form of H, tuna, although Professor Schmitz 



