-, 251 - 



of the cell has often a longer or shorter root-like prolongation 

 (fig. 5c,e), upon the lowermost end and sides of which we find 

 a great number of small unicellular rhizoids which grow out, one 

 from each of the numerous small cells occurring here very similar 

 to those found in Valonia. Also higher up on the cell we often 

 find many of these small cells arranged as a rule in rows (fig. 5^), 

 some of them also more scattered. How far the origin of these 



Fig. 5. Dictyosphœria favulosa (Ag.) Decsne. 



a. part of a thallus with cells in division in different stages of development (6:1), b. transverse 

 section of thallus with cell newly divided (compare text) (20:1), c. d. e. young plants (10:1), 

 /. chromatophores with pyrenoids and nuclei (250 : 1). 



young plants are due to zoospores is difficult to say, most pro- 

 bably they are not; in the abundant material I have collected not 

 a trace of zoospore-formation has been found and this has never 

 been found by other investigators. Much seems to suggest that 

 these young individuals are due to cells loosened from the thallus 

 of other specimens. This seems also to be indicated by the fact, 

 that the cells themselves are often densely covered by Melobesieæ 

 and other epiphytes. Perhaps some of them also can have their 

 origin from aplanospores, about which more later on. 



