CCENOBIE.E 



2[)7 



protoplasm again breaks up into zoospores, which swarm about for twenty 

 or forty minutes within a sac which protrudes out of the protoplasm. 

 When they come to rest, they arrange themselves within the sac into a 

 small net consisting of from 200 to 300 cells, which gradually grows to 







0^%ei 











Fig. 260. — Hydrodictyon utriculatum Roth. A, net (natural size). B, mesh (x lo), C, megjazoo 

 sporange ( x 300). D, megazoospores ( x 600). E, gametange with zoogametes ( x 300). (After 

 Cohn.) 



one of the ordinary size. In some of the polyhedra smaller and more 

 numerous microzoospores are formed ; but they also appear to unite 

 again into a net without displaying sexual functions. 



Literature. 



Nageli— Gattungen einzelliger Algen, 184^9, p. 92. 



Braun — Verjungung in der Xatur, 1851 (Ray Soc. , Bot. and Phys. Mem., 1S53) ; and 



Algae unicellulares, 1S55. 

 Pringsheim — Monber. Berl. Akad. , i860, p. 775 (Quart. Journ. Micr. Sc. , 1S62, pp. 



54 and 104). 



