14 Marine Cvanophyceae from Easter Island. 



By 



JOHS. BOYE PETERSEN. 



In some of the samples of marine algae from Easter Island investigated 

 by Dr. F. BORGESEN^ Cyanophyceae occurred. Dr. BoRGESEN asked me to 

 undertake the investigation of this group, and I accepted his request with 

 pleasure. As no Cyanophyceae have hitherto been recorded from Easter Is- 

 land, I presume that even the most sketchy list may be of interest, and I 

 have therefore attempted to determine the often incompletely developed spe- 

 cimens found in the samples. Only in 3 samples preserved in formalin and 

 in one dried sample I found determinable Cyanophyceae. All the samples 

 were collected at Hanga Piko in the litoral zone (June 1917). 



P"am. Oscillatoriaceae. 



Lyngbya C. Ag. 



L. sordida (Zanard.) Gom. 



GoMONT, Monogr. des Oscillariees II, Ann. Sc. nat. 7' ser. T. 16, p. 126, 

 pi. II, fig. 21. 



This species occurred in the dried sample, growing in Zonaria variegaia. 

 Area of distribution: Atlantic coast of Europe, Mediterranean Sea, 

 West Indies, P'riendly Islands (Pacific Ocean). 



Hydrocoleuin Kiitz. 



H. comoides (Harv.) Gom. 



GoMONT, Monogr. I, 1. c, T. 15, p. 335, pi. XII, fig. 3 — 5. 



Among Hypnca Esperi I found a form with trichomes measuring 18 — 20 |j- 

 in diameter. The apex was attenuated and often provided with a flat calyptra. 

 The trichomes were thus exactly in accordance with those of H, comoides, and 



^ The natural history ot Juan Fernandez and Easter Island edited by Dr. Carl Skottsberg. 

 Vol. II, p. 247. 



