41 



Whilst in the normal vegetative cells the chromatophores 

 with pyrenoids and nuclei form a net-work in the wall-plasma, 

 in those in question the cell contents were aggregated into irre- 

 gularly formed bodies consisting of a larger broad plate with 

 or without opening in the middle of the cell, from which narrower 

 prolongations ran down along the sides of the cells, giving them 

 a very characteristic appearance; in the walls of some of these 

 cells 2 — 4 holess were found, through which the zoospores could 

 escape (Fig. 25'^).% 



Also in specimens from the Malayan Archipelago Prof. 

 Arnoldi has found zopspore-formation (comp. the note p. 37). 



Fig. 25. Didyosphceria van Bosseoe Borgs. 

 Cells in zoospore-formation (ca. 20:1). 



The cell contents in the vegetative cells have a very great 

 likeness to what is found in the above-mentioned species. With 

 regard to the hapteras along the edges of the cells I may refer to 

 Miss Crosby's description and figures with which they show a 

 great likeness, though on the other hand they are not so regularly 

 arranged and also differ somewhat in shape from those in D. fcwulosa. 



This species is found in rather exposed localities in shallow 

 water growing on rocks where it is constantly dashed by the waves. 



St. Croix: Cane Bay, Sandy Point. 



The small specimen I had referred to Dictyosphseria inter- 

 media Weber-van Bosse with much doubt and which was found 

 growing together with Dictyosphseria van Bosseae I prefer here 

 to leave undetermined as it most probably belongs to D. van Bosseae. 



