F. Børgesen: Rhodophyceæ of the Danish W. Indies. 



59 



ning along the walls of the cells; in their middle a well developed 

 pyrenoid is present. 



The cells in the ends of the filaments bear now and then 

 thin hyaline hairs (Figs. 60, 62); these are about 5,5/^ thick and 

 reach a length of about 300 — 400 /i. 



Fiff 62 Acrochætium Liagoræ nov. spec. Part of a plant with sporangia 

 ^' and hair. (About 400 : 1). 



As mentioned above the monosporangia are developed in the 

 end of the branchlets or more rarely upon the main filaments; 

 they are obovate-globular of shape, about 20// long and 14// 



broad. 



Of the species mentioned by Rosenvinge I think it comes 

 nearest to Acrodiætiiim (Chantransia) Pohjidis Rosenv. 



This species has only been found once at the south coast of St. Croix. 



22. Acrochætium ernothrix nov. spec. 

 Thallus cæspitulosus, ca. 400// altus. Pars basalis non certo 

 observata est. Fila erecta a basi ramosa. Rami principales stricti, 

 in inferiori parte paucis, in superiori numerosis ramis et ramulis 



instructi. 



Cellulæ ramorum 5—6// latæ et 15—18/« longæ, cylindricæ, 

 chromatophorum zonatum prolongationibus irregularibus instruc- 

 tum et pyrenoide centrali munitum continentes. 



Ramuli sporangiferi e 2—3, rarius pluribus cellulis compo- 

 siti, ad apicem versus angustati in pseudopila longa producti. 

 Monosporangia sessilia aut pedicellata, lateralia 2—3 seriatim 

 posita, rarius terminalia, ovato-oblonga, 8 — 10// longa et b—Q(i 



lata. 



Of this characteristic species I have only succeeded in finding 

 a single specimen. It was growing upon a Cewiroceros-plant for- 

 ming a small tuft. 



