MARINE ALGAE FROM EASIER ISLAND 249 



(I. c.) is a rather variable plant. Quite as in the West Indian plants the present 

 one formed a reticular tissue, the endophyte utilising the larger place left above 

 the walls of the peripheral cells in the host plant. 



The cells are 8 -15 p. long and 7 — 8 fj. broad, of a rather irregular shape, 

 often about oval, mostly as long as broad, but shorter ones are common too. 



Fig. 1. Endoderma viride (Rke) Lagerh. from Laurencia claviformis. In one of the cells zoo- 

 spores are seen. C. w0 /u 



The cells contain much starch. The shape of the chromatophore could 

 not be determined, probably because the material had been kept too long in 

 formaline. 



Cells with zoospores were found now and then. 



Area of distribution: Atlantic coasts of Europe and N. America, West 

 Indies, Easter Island. 



Fam. Cladophoraceae. 



Cladophora Kiitz. 



C. spec. 



Together with Gelidium pusillum a small Cladophora was found upon a 

 shell. It had vigorous rhizoids deeply immersed in the substratum. 



The basal cells were 2 — 3 mm long and 150 — 175 \s. thick, the upper cells 

 shorter, but a few cells only were developed. The cell walls were thick and 

 stratified. 



The largest plant found was 5 mm long. 



C. (Aegagropila) socialis Kiitz. — Fig. 2. 



Kutzing, Spec. Alg., p. 416. Tabulae Phycologicaa, vol. IV, tab. 71. Rein- 

 bold in A. Weber van Bosse, Liste des Algues du Siboga, I Myxophyceae, Chloro- 

 phyceae, Phaeophyceae, p. 82. 



To this species, originally described by KUTZING from Tahiti, I refer a 

 plant forming extensive, soft, Vaucherza-Wke tufts. On the upper side of these 

 tufts the filaments are not much branched, often being quite simple for a 

 considerable distance. The ramification is subdichotomous, the side branches 



