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 /*. 



Fig. 62. Acrochsetiwn Liagorse 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 Acrochdstium (Chantransia) Polyidis Rosenv. 



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



22. Acrochsetium ernothrix nov. spec. 



Thallus c^spitulosus, ca. 400 // altus. Pars basalis non certo 

 observata est. Fila erecta a basi ramosa. Kami principals stricti, 

 in inferiori parte paucis, in superior! numerosis ramis et ramulis 

 instructi. 



Gellula? ramorum 5 6/^ latse et 15 18 fj. Ionga3, cylindrica?, 

 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 pedicellate, lateralia 2 3 seriatim 

 posita, rarius terminalia, ovato-oblonga, 8 10^ longa et 5 6^ 

 lata. 



Of this characteristic species I have only succeeded in finding 

 a single specimen. It was growing upon a Centroceras-plani for- 

 ming a small tuft. 



