MARINE ALGAE FROM EASTER ISLAND 



263 



Easter Island the sori do not seem to be restricted to the vicinity of these but 

 are formed everywhere on the surface of the thallus. Otherwise, the Pacific 

 specimens agree very well with West Indian ones. 



Area of distribution: Widely spread in all warmer seas. 



Hydroclathrus Bory 



II. cancellatus Bory 



Bory, Diet, class. VIII, p. 419. Harvey, Phycolbgia Australica, pi. 98; Nereis, 

 p. 120, tab. IX A. Thuret et Bornet, fitudes phvcologiques, 1878, p. 12. Mit- 

 chell, M. in Murray, Phycol. Memoirs, p. 53. 



The specimens found agree very well with West Indian plants. The 

 thallus consists of a medulla of large roundish-polygonal cells, and a small- 

 celled cortex. Where two strings of the network come into contact the epider- 

 mal cells grow out in a rhizoid-like fashion, uniting in this way different parts 

 of the net work of the thallus. Compare my fig. 139, 1. c. The material was 

 sterile. 



Area of distribution: Seems to occur in all warm seas. 



Chnoospora J. Ag. 



C. fastigiata J. 



Fig. 11, 12. 



Ag. var. pacifica J. Ag. 



Agardh, J., Spec. Alg., vol. 1, 1848, p. 171. — 

 Chnoospora pacifica J. Ag., Nya alger fran Mexico (Ofvers. 

 K.. Vetensk.-Akad. Forh., 1847, P- 7)- 



Some small specimens of a brown alga, richly 

 provided with cryptostomata, from which long hairs 

 protrude giving the plant a nearly moniliform appea- 

 rance, seem to be referable to the genus Chnoospora 

 as a small form of Chn. fastigiata var. pacijica. 



The largest specimen was about 6 cm high, 

 the others 4 to 5. The plant is fastened to the 

 substratum by means of a rather large irregularly 

 shaped disc from which the erect shoots arise. 



The ramification is mostly dichotomous, some- 

 times tri-polychotomous but rather irregular, with 

 the whole branch system more or less fastigiate, 

 even if a tendency to lie in the same plane is rather 

 obvious. 



In the basal part the branches are about 1 mm 

 thick, rarely more, higher up thinner. The thallus is a p io . 



1 1 . Chnoospora fastigiata 



little compressed, the transverse section being oval. J. Ag. Part of a plant, c. */» 



