— 201 — 



witness, showing that the protoplast of the cell is nowhere con- 

 nected with the cell-wall, but is always separated from it by a 

 distinct interspace. I do not doubt that the protoplast in the 

 living cells extends right to the apex of the process, but when 

 the plasma contracts, in the moment when it dies, it will primarily 

 draw back from the process, its form approaching as much as 

 possible to the globular form. 



It is quite true that the cell apex often shows a little dila- 

 tation, but I have never seen such a 

 collar-formed enlargement as that 

 drawn by Lemmermann. The thin cell 

 wall at the bottom of the slight depres- 

 sion in the apex of the cell was evi- 

 dently overlooked by Lemmermann; 

 it is in fact difficult to see. It did not 

 appear distinctly till treated with 

 »Eau de Javelle«. 



It is possible that the fine con- 

 nection string between the proto- 

 plast and the freely projecting »Pseu- 

 doflagellum« may be a fine proto- 

 plasma string which was caught by the 



Cell- wall at the bottom of the depres- Fig. 3. Rand cell of Pediastrum 



Sion, When the Cell plasma was shrink- clathratum from Bure Sø. The 

 . sample preserved in formalin. 



mg owing to the dying of the cell. (x 1200). 



Finally I shall draw attention to 

 the fact that in the sample in question from Bure Sø ( 31 / 7 1909) 

 I found, as early as in 1911, by means of Löfflers cilia-staining 

 method very beautiful tufts of bristles in the cell-points. 



It has thus been ascertained: 



1) that Lemmermann's »Pseudoflagella« in Pediastrum clathra- 

 tum (Schröter) Lemm. are identical with the tufts of brist- 

 les found by me. 



2) that these are found in the living specimens, whereas the 

 »Pseudoflagella« only are to be seen in the preserved indi- 

 viduals. 



3) that the walls at the end of the processes in the Pediastrum 

 species are never perforated. 



