11 



cells and between these there are thinner parts still consisting of 

 a single row of cells (Fig. 5 a). 



Figs. 5 d, e, /, g show transverse sections of filaments in differ- 

 ent stages of development; fig. 5 d is of a filament still consisting 

 of a single row of cells, in fig. 5 e we find two cells and in fig. 5 / 

 and g several. As the figures show the cells lie scattered without 

 order in the whole filament. In this my plant differs essentially 

 from the description of SCHMITZ (1. c.) where the thallus is said 

 to be : "der ganzen Lange nach rohrig hohl, mit gallertgefulltem 

 Hohlraume". 



Now and then especially from the thicker parts of the fila- 

 ments branches grow out; these are commonly short, proliferation- 

 like, consisting of a single row 

 of cells (Fig. 5 b, Fig. 6) ; only 

 rarely I have found them longer 

 and more like the main filaments. 



Each cell contains a starlike 

 red-violet chromatophore in the 

 middle of which a large pyrenoid 

 is present (Fig. 6). 



In some filaments all or 

 nearly all cells were emptied, 

 the few remaining cells were nearly 

 spherical and with a granulated 

 contents. I take these cells for 

 the gonidia. I have not succeeded 

 in finding other kind of organs 

 of propagation. 



While my plant seems to 



agree quite well with the description of MONTAGNE it differs as 

 pointed out above from that of SCHMITZ'S by its solid thallus. 

 MONTAGNE referred the plant to the genus Compsopogon, while 

 SCHMITZ created for it the genus Bangiopsis. It comes surely 

 near to Bangia but differs essentially from this genus by the 

 want of rhizines at the base and by the common presence of 

 proliferations and especially by the rather irregular cell-division, 

 the cells in Bangia being divided by radial walls and these as a 

 result are generally wedge-shaped. 



The plant has been found only once growing upon a buoy in the 

 harbour of Christianssted, St. Croix. 

 Geogr. Distrib. Guiana. 



Fig. 6. Bangiopsis subsimplex (Mont.) 



Schmitz. Part of a thallus showing 



cells with chromatophores and pyre- 



noids. (About 250 : 1). 



