MARINE ALGAE FROM EASTER ISLAND 25 1 



while cell division in Cladophoropsis (as far I have been able to observe on 

 preserved material of CI. membranacea) is realised in the peculiar way 1 have 

 called segregative cell division. 



The species, originally found at Tahiti, has been collected at the Lucipara 

 Islands by Mme. WEBER. 



Area of distribution: Pacific Ocean, Malay Archipelago. 



Fam. Valoniaceae. 



Valonia Ginn. 

 V. ventricosa J. Ag. 



Specimens as large as dove's eggs are found. They were fastened to 

 other algae and were also themselves very much utilized by epiphytes. 



The specimens seem to agree very well with others collected by me in 

 the West Indies (1. c, vol. I, p. 27). In both cases they were fastened to the 

 substratum by means of rhizoids growing out from the small lentiform cells in 

 the basal end of the large cell. 



In some of the specimens a good number of small roundish cells were 

 found enclosed in the large mother cell, as described by MURRAY. 1 On the 

 base of my West Indian material I arrived at the conclusion that these bodies 

 owed their origin to abnormal conditions, but after I have seen the Pacific 

 specimens I agree with MURRAY in considering them as quite normal organs 

 of vegetative reproduction formed by a kind of free cell division — segregative 

 as I have called this peculiar division modus found in so many related tropical forms. 



Another sample of algae contained some few specimens of more elongated 

 shape about 2 cm long and S U — I cm broad. I dare not say, if these specimens 

 more rightly ought to be referred to V. Forbesii Harv. but had they come 

 from the West Indies I would without doubt have considered them as forms 

 of V. ventricosa. As is the case in this species they were covered by epiphytes, 

 especially Melobesiacea?, while V. Forbesii, according to Mme. WEBER 2 , is less 

 used as substratum. 



Area of distribution: West Indies, Malayan Archipelago, Tahiti, Easter 

 Island. 



Rhipidiphyllon Heydr. 



Rh. reticulatum (Asken.) Heydr. — Fig. 3, 4. 



Hevdrich, F., Beitrage zur Kenntnis der Algenflora von Ost-Asien besonders 

 der Insel Formosa, Molukken- und Liu-kiu-Inseln. Hedwigia, 33. Bd., 1894, p. 281. 

 — Anadyo?nene reticulata Askenasy, Forschungsreise S. M. S. » Gazelle* IV. Theil, 

 Botanik (Algen), p. 5. 



The thallus (Fig. 3) forms small, 2—4 mm broad, cristate and excentric 

 bodies fixed by means of vigorous rhizoids to the host plant (Galaxaura). 



1 Murray, G., On Halicystis and Valonia, in Murray, Phycological Memoirs, Part II, 

 1893, p. 50-1. 



* Weber-van Bosse, A., Liste des algues du Siboga, I, Myxophyceae, Chlorophyceae, 

 Phaeophvceae, p. 59. 



