37 



outgrowth from cells at the base of the plant (Figs. 19, 20 c, d, e). 

 Where their walls come near to the substratum the small cells 

 are present in great number and from them rhizoids grow out 

 and attach the plant. Here the arrangement of the small cells 

 is more irregular. 



With regard to the wall-plasma, we find, as also pointed 

 out by AsKENASY^) and Miss Crosby^), the numerous rather 

 large roundish-polygonal chromatophores of the wall plasma 

 becoming connected with thin prolongations forming in this way 

 a more or less open net-work (Fig. 20 /). In the chromatophore 

 one — three large pyrenoids are present. Near to the one side of 

 the chromatophores the numerous oblong, rather large nuclei 

 are met with. 



In the small cells also some few chromatophores with pyre- 

 noids occur (Fig. 21 e), furthermore also a single nucleus or in 

 the larger oblong cells even two. That chromatophores occur in 

 the small cells is also mentioned by Heydrich 1. c. p. 468. The 

 outer wall shows cross-wise striations. 



With regard to a comparison of the development of the thal- 

 lus as I have found it with that found by earlier authors^) I refer 



1) AsKENASY in Forschungsreise S. M. S. »Gazelle«, IV. Theil, Botanik. 

 1888, p. 8. 



-) Crosby in »Minnesota Bot. Studies*, 3. Series, Part 1, 1903, p. 61. 



') After the publication of my paper Professor W. Arnoldi in »Flora«, 

 vol. 105, Heft 2, 1913, p. 144 has given a description of the devel- 

 opment of the thallus of this genus and his examination confirms in 

 all essentials the results of mine. 



Arnoldi who only mentions mine in a note at the end of his 

 paper, not referring to my description of the cell-division in Dic- 

 tyosphaeria nor to the very similar I earlier had found in Sipho- 

 nocladus tropicus, describes the cell division in this way: »Wahrend 

 der Theilung schrumpft nun der Protoplast durch Plasmolysierung 

 auf die Halfte oder noch melir seiner urspriinglichen Grosse zuriick 

 und teilt sich in radiarer Richtung in zwei, vier, seltener mehr Teile«. 

 Having not been able to study the division of the protoplast upon 

 living material I cannot with certainty say how it is carried out, but 

 I have found the 3 — 6 or seldom more balls lying without order in the 

 mother-cell, in every case when more than four are present (compare 

 my Fig. 21a); first later on during their growth they are arranged in 

 the same plane as all the other cells in the plant. As to the propaga- 

 tion Prof. Arnoldi writes p. 157 : »Unter dem grossen Material von 

 D. favulosa und D. Versluysi, das mir zur Verfiigung stand, gelang 

 es mir, einige Zellen zu finden, welche entweder sich zur Fortpflan- 

 zung vorbereiteten oder schon bewegliche Elemente ausbildeten«. 

 As I have pointed out, I have not succeeded in finding any trace of 



