— 170 — 



over one or two tufts between the spines on the outward side. 

 All the bristles mentioned project nearly in the plane of the coe- 

 nobium. But moreover it is very common to find 3) some other 

 tufts fixed at the middle cells; there are generally four on each: 

 two at the upper and two at the under side projecting at right 

 angles to the plane of the coenobium. 



The bristles of this species are generally very thin, about 0.2//. 

 I have measured very long bristles on a specimen from a little 

 pond in the village Stavnsholt (another pond than the above men- 

 tioned) taken 23 /s 1910. The cells were 22 ^ and the bristles up 

 to 80 p. long. In the same pond a specimen had bristles up to 

 128 fi long. Almost everywhere, where I have found Scenedesmus 



cent writers considered as a variety of the preceding species, 

 what also in my opinion is right. Concerning the bristles it only 

 differs from the typical quadricauda therein that the bristles are 

 stronger and therefore deeper coloured in the staining preparations. 

 The length of the bristles is up to about 50 p. The tufts are 

 generally placed in a manner like that of the quadricauda. 



I have found bristled specimens in the pond of the Botanical 

 Garden and in 6 ponds in North Sealand. 



Scenedesmus acutus Meyen. Fig. 5 [Meyen 1828 pag. 775]. 

 [Ghodat 1902 pag. 210]. This species has only bristles on 

 the points of the cells. In the staining preparations these 

 points appear deeper coloured than the other parts of the 

 cell. In an eight-celled coenobium where the cells were 20.5 ß 



quadricauda making an 

 essential part of the 

 plankton, I have been 

 able to show bristles at 

 them. I have thus found 

 them in Bagsværd Sø, 

 in the pond of the Bo- 

 tanical Garden (Copen- 

 hagen) in 9 ponds in 

 North Sealand and in 

 some ones near Vejle 

 (Jutland). 



Fig. 5. Scenedesmus acutus Meyen. Löfflers method, (x 730). 



Scenedesmus Opoli- 

 ensis Richter is by re- 



