MARINE ALGAE FROM EASTER ISLAND 271 



than the vegetative cells I regard them as asexual sporangia. They are about 

 5 [j. in diameter. 



E. Laurenciae. comes near the preceding one but differs by its shorter and 

 proportionally thicker cells, by its richer ramification and by the development 

 of a coherent layer in the centre of the thallus. 



Area of distribution: Kndemic. 



Fam . 1 1 e 1 m i n t h o c 1 a d i a c e a e. 



Acrochaetium Naeg. 



A. (Chantransia) nionili forme Rosenv. — Fig. 17 a. 

 Rosenvinge, L. Kolderup, Mar. Algae of Denmark, Part I, p. 0,9. 



The enormous distance between Easter Island and the original locality 

 certainly aroused some doubt as to the identity; still, the few specimens observed 

 seem to answer so well to the description and figures of RoSENVlNGK that it 

 seems natural to bring them to his species. 



From the basal spore, that does not differ much from other cells, several 

 filaments arise. The cells are swollen in their middle, about 10 — 11 \l long and 

 8-9 {A wide. In one of the plants a long hair was found. The cell contents 

 was very dense; the pyrenoids situated a little above the centre of the cells 

 suggest a stellate chromatophore. 



The plants are epiphytic on Dictyopteris repens. 



Regarding the affinities between this species and Acrochaetium catenulatum 

 Howe 1 or A. crassipes Borgs. 2 , compare Howe's and my own remarks 11. cc. 



Area of distribution: Denmark, Easter Island. 



A, discoideum nov. spec. — Fig. 17 b — d. 



Thallus epiphyticus, caespitosus, usque ad 300 {J. altus. Pars basalis disci- 

 formis, unistratosa substrato (0: foliis Sargassi) firme adhaerens, e filis repentibus 

 ramosis, initio inter se discretis, postea plus minus confluentibus constructa. 



Cellulae filorum repentium irregulariter curvatae aut plus minus tumidae, 

 lat. 3— 4 {x, long. 9— 1 2 [j., diametro triplo fere longiores. 



Fila erecta, e disco basali orta, simplicia, stricta, usque ad 200 — 300 ;j. et 

 ultra alta, superne gradatim in pseudopila transformata, e cellulis cylidricis ca. 

 6—8 (x latis et (in parte basali) ca. 15 ^ longis composita. 



Sporangia oblonge-ovata aut in disco sessilia aut pedicellata, ca. n — I3[J. 

 longa et 6 — 8 jx lata. 



This species was found on a leaf of a dried specimen of Sargassum, whose 

 surface it nearly covers. The basal layer spreads widely over the surface of 

 the substratum to which it is firmly attached. A single plant may reach more 



1 Howe, M. A., Mar. Algae of Peru, p. 84. 



2 Borgesen, F., Marine Algae of the D. W. I., vol. II, p. 20. 



