— 200 — 



um feine Gallertfäden. Sie färben sich in Gentiana- oder Safranin- 

 lösungen nur langsam«. 



Later these »Pseudoflagella« have been mentioned in Pa- 

 schels Süsswasserflora Heft 5, p. 89 fig. 50, where the author 

 apparently applies Lemmermann's observation on the openings 



in the points of the cell processes to 

 all the species of Pediastrum. 



Already in 1898 0. Zacharias found 

 tufts of fine bristles in the rand-cell 

 processes of Pediastrum duplex, and 

 he assumed the bristles to be a buoy- 

 ancy apparatus, this view being con- 

 firmed by all later authors. 



In 1912 I mentioned (Boye Pe- 

 tersen 1912 p. 166 fig. 2 and p. 171 

 fig. 7), not knowing Lemmermann's 

 above mentioned paper on »Pseudo- 

 flagella«, that I had found tufts of 

 bristles in the points of the rand-cells 

 of Pediastrum clathratum projecting 

 from a little knob evidently of the 

 same substance as the bristles. This 

 little knob is situated in a slight 

 depression at the end of the cell-pro- 

 cesses, but separated from the cavity 

 of the cell by a distinct cell-wall. Con- 

 cerning my further observations I may 

 refer to the mentioned paper. 



When I later got acquainted with 

 Lemmermann's publication I commen- 

 ced a re-examination of my old plancton samples from 1911, 

 wherein the said Pediastrum clathratum occurred. To be sure, I dis- 

 covered some formations exactly resembling Lemmermann's »Pseudo- 

 flagella«; only I could not see any connection between the pro- 

 toplast of the cell and the »Pseudoflagellum« which projected 

 from the cell apex. In my fig. 3 the appearance of the bristles 

 is shown. The sample in question was preserved in formalin 

 (formaldehyd). The samples investigated by Lemmermann and 

 issuing from Paraguay were evidently also preserved, and most 

 likely in formalin. To this Lemmermann's drawing also bears 



Fig. 2. Rand cell of Pedia- 

 strum clathratum from Bure 

 Sø. Coloured by the aid 

 of Löffler's cilia-staining 

 method, (x 1200). 



