244 Ulothricaceae and Chaetophoraceae 



9, io. Tribonema utriculosuvi. Young and mature filaments from a single col- 

 lection (418), p. 186. 



II. A mature vegetative filament (579). 



Plate 26 (575 : 1) 



1. Microthamnion Kuetzingianum. A plant of moderate size, showing zoospore 

 formation and cells evacuated by zoospores (532), p. 191. 



2. Microthamnion strictissimum. Lower part of a plant of moderate size, corre- 

 sponding closely to Rabenhorst's type material (524), p. 191. 



3. 4. End branches of the same. 



5. End branches from a short and slender form (613). 



Plate 27 (575: 1) 



1. Microthamnion strictissimum macrocystis. Nearly all of a medium-sized plant 

 (608), p. 192. 



2. Microthamnion Kuetzingianum. A medium-sized plant (532). 



3. 4. Young plants (561 B). 



Plate 28 



1. Myxonema lubricum. Middle portion of the typical form (638), p. 196 



(35o: 1). 



2. Setiferous state, upper portion (515 A) (350: 1). 



3. 4. Myxonema lubricum varians. Formation of zoospores (456), p. 198 



(575= I)- 



Plate 29 ( 350 : 1 ) 



Myxonema amoneum. Fig. 2 joins Fig. I at the point marked X > there was an 

 interval of six cells between Fig. 2 and Fig. 3 (558), p. 199. 



Plate 30 (350: 1) 

 Myxonema sububigerum ( 374) , p. 200. 



Plate 31 (350: 1) 

 Myxonema ventricosum. The small figure joins the main stem twenty cells be- 

 low (359), p- 201. 



Plate 32 ( 350 : 1 ) 



1. Myxonema tenue. The main stem, drawn with the diameter slightly too great 

 in comparison with the other figures in this genus (615 B), p. 202. 



2. Setiferous state, a branch from near the summit (458). 



Plate 33 (350: 1) 

 I, 2. Myxonema aestivale. Lower part of a plant ; Fig. 2 joins Fig. I at the point 

 marked X (4°3)> P- 205. 



3. Upper part of another plant (654). 



4. 5. Myxonema lubricum varians. A portion from the upper part of a plant ; 

 the diameter is slightly too small in comparison with that of M. tenue (336), p. 198. 



Plate 34 (350: 1) 

 Myxonema glomeratum (591), p. 205. 



