MARINK ALGAE FROM EASTER ISLAND 



297 



Ceramothamnion Richards. 



C. Codii Richards. 



Richards, Ceramothamnion Codii, A new rhodophyceous alga (Bull. Torrey 

 bot. Club, vol. 28, p. 57). 



Some few small loose-lying fragments have been found only which I think 

 are referable to this plant. What species the host plant has been I can not 

 say; no Codium was among the material handed over to me. 



Dr. H. E. PETERSEN kindly inspected the material and confirmed the 

 determination. 



Area of distribution: Bermuda, Easter Island. 



Ceramium (Roth) Lyngb. 



By Dr. H. E. PETERSEN. 



C. cruciatum Collins & Hervey. — Fig. 37. 



Collins & Hervey, The algge of Bermuda, 191 7, p. 144. 



In referring the specimens from Easter Island to this species I base this 

 upon the figures of Mme. WEBER, Liste des algues du Siboga, III, Rhodo- 

 phyceae, p. 331. 



Fig. 37. Ceramium cruciatum Collins & Hervey. a top of filament, c. e %; b part of filament 

 lower down, c. 240 /i; ctetrasporangia, c. t40 /i. 



According to COLLINS & HERYEY Ceramium cruciatum has »cortication 

 consisting of cells elongate in the direction of the filament». Mme. W'EBER 

 having seen an original specimen of this species now gives a figure of a cortical 

 belt, in which the cells are not arranged in longitudinal rows as in the figures 



