— 362 — 



Woltke (Urospora p. 69) distinctly points out that the zoospores of 

 this species are produced by successive divisions, while the zoospores of 

 Urospora mirabilis Schmitz (cfr. my footnote p. 361) are produced by 

 simultaneous divisions. I have in my material of U. mirabilis never seen 

 the mother-cells of the zoospores in stages of divisions, which distinctly 

 show successive divisions, and I have also never seen the parietal proto- 

 plasm divided into numerous six-sided portions as in Urospora Worm- 

 skioldii (Rosenv. Grl. Havalg. p. 920) and U. incrassata (Kjellman Blasto- 

 physa och Urospora p. 13, fig. 11). 



Fig. 11. Urospora Hartzii Rosenv. 

 a the basal portion of a filament showing the rhizoids, b the upper part of the 

 rhizoid-bearing portion, c fragment of the filament a little above the rhizoid- 

 bearing portion; d from the upper part and e from the uppermost part of the 

 filaments, showing sporangia; b, c, d, e fragments of the same filament. (126: 1.) 



Urospora Hartzii Rosenv. Grl. Havalg. p. 922, fig. 38. 



The specimens which I have referred to this species are up to 4 cm. 

 long, 29 — 60 [i thick below and 87 — 120 p. thick above. The relation 

 between the length and the breadth of the cells varies from V2 to 1 V2. 

 The cells of the lower part of the filaments, above the rhizoids are usually 

 short, but filaments with elongated cells above the uppermost rhizoid-bearing 

 cell, as in Urospora Wormskioldii, also occur. The upper part of the 

 filaments of my specimens is usually fructiferous and contains longer cells. 

 As far as I can see in my material the young filaments seem to be 

 divided over the whole, but as the upper part of the filaments becomes 

 fructiferous the vegetative divisions are localized in the lower part. Both 



