— 151 — 



To this description I may add that the plant, like Chœtomorpha, 

 forms loose-lying entangled masses, the filaments twisted between 

 each other. The proliferations occur very seldom, most often only 

 at the apices of the filaments (fig. 12 c) ; only once have I found 

 a proliferation growing out from the side of a filament far from 

 the top (fig. 12 d). While the filaments commonly consist of three 

 rows of cells (figs. 11a, b, e) the thinner proliferations only consist 

 of two and at last of a single row of cells only. The filaments 

 consisting of 3 rows of cells are solid (fig. 12 e), while the thicker 

 but rarer filaments with several rows of cells are hollow in the 

 middle (fig. 12 f). The chromatophore lies near the outer wall of 

 the cells and contains two pyre- 

 noids, seldom three (fig. 12 b.) 



Found several times in the 

 Bovoni Lagoon, St. Thomas. It 

 was partly found entangled among 

 Polysiphonia Havanensis growing 

 upon the roots of the mangroves, 

 partly also forming loose-lying mas- 

 ses together with other algæ, e. g. 

 Rhizoclonium Kochianum KQtz., 

 Lyngbya majuscula Garv., Entero- 

 morpha plumosa Kütz., etc. 



Blastophysa rhizopus Rke. 



Reinke, Atlas deutscher Meeres- 

 algen, pl. 23. Hub er, Contributions à 

 la connaisance des Ghaetophorées epi- 

 phytes et endophytes et de leurs affinités. 

 (Ann. sc. nat., bot., sér. XVI, p. 332.) 



Growing endophytic in the 

 thallus of Nemalion Schrammt 

 (Gr.) was found a green alga which 

 seems to come very near, most 

 probably being identical with 

 Blastophysa rhizopus Rke. 



Quite in agreement with the 

 description of Reinke the large 



cells of our plant had a very variable shape and from these long, 

 colourless, rhizoid-like filaments grow out. Upon most of the cells 



Fig. 13. Blastophysa rhizopus Rke. 



About 125 : 1. 



