360 



Conjugate 



('79) and afterwards by Klebs ('85), Schroder ('02) and others. In various 

 species of Closterium one end of the cell becomes temporarily fixed and the 

 whole cell then performs swinging movements with the fixed end as a pivot. 



rr\ 



Fig. 224. Various filamentous types of Desmids. A, Desmidium occidental W. & G. S. West. 



B, D. coarctatum yar. cambricum W. West. C and D, Gymnozyga moniliformis Ehrenb. ; 



C, single cell ; D, dividing cell. E G, Phymatodocis Nordstedtiana Wolle. H,Phy.irregularis 

 Schmidle. I, Spondylosium ellipticum W. & G. S. West. J L, Sphserozosma excavatum 

 Ealfs ; K and L, zygospores. M, Spondylosium secedens De Bary. N, Sphserozosma granu- 

 latum Eoy & Biss. var. trigranulatum W. & G. S. West. O, Spondylosium rectangulare 

 (Wolle) W. & G. S. West, a, front view; b, vertical or end view; c, side view; d, basal view 

 of semicell. A and B, x 333 ; G 0, x 433. 



Sooner or later the other pole becomes similarly attached and further 

 oscillatory movements are carried out. Sometimes, as Stahl showed in 

 CL moniliferum, the cell swings completely over through 180 and then 



