Schwarze: Cleavage in Sporangia 147 



taneous, as describing spore formation : " In den Zoosporangien der 

 Saprolegnien wird, wie aus zahlreichen angaben bekannt, eine 

 grosse Anzahl Schwarmsporen simultan aus dem gesammten Proto- 

 plasmatischen Inhalte des sporangium gebildet." 



Dangeard (1.4), studying spore formation in Synchytrium tar ax - 

 aci, calls it simultaneous fragmentation. Popta (42), who was 

 concerned with the question of periplasm and spore formation in 

 the so-called Hemiasci, refers to spore production in Protomyces 

 bellides as " Simultan und sehr rasch." Barrett (3), investigating 

 some species of Olpidiopsis, states that segmentation of the spo- 

 rangial contents is apparently simultaneous throughout. 



Cornu (12), studying the Chytridiales, parasitic on Saprolegni- 

 ales, refers to spore formation in Olpidiopsis as follows : " Presque 

 sans transition, le contenu s'organise en petites masses spheriques, 

 futures zoospores." He claims that a similar phenomenon occurs 

 in the sporangia of Rozella and Woronina. Thus in the above- 

 mentioned genera the spore plasm is said to organize, with practi- 

 cally no transitional stages, into spherical masses. 



Biisgen, who, as already mentioned, made a comparative study 

 of a number of Saprolegniales, Peronosporales, and Mucorales, 

 combines the conceptions of cell-plates and division, not always 

 simultaneous. He says : " Unter auftreten von Zellplatten theilt 

 sich der gesammte Inha.lt des Sporangiums — nicht immer simul- 

 tan — in etwa gleich grosse, meist nicht regelmassig begrenzte 

 Portionen. . . 



Rothert (46), in a quite thorough piece of work on Saprolegnia, 

 figured clefts from the central vacuole proceeding outward. Hum- 

 phrey (29), studying the Saprolegniales of America, merely states 

 his agreement with Rothert as to cleavage and spore formation. 



Thaxter (51) finds spore formation simultaneous in Syncepha- 

 lastrum, but occurring by progressive constriction in Syncephalis 

 pycnosperma, S. nodosa, S. Wynneae, S. cordata, and in a Syn- 

 cephalis closely allied to the latter. 



Kusano (32) and Griggs (23) hold that spore formation in 

 Synchytrium puerariae and Rhodochytrium, respectively, may be 

 either simultaneous or progressive. Davis (15), studying spore 

 formation in the sporangia of Saprolegnia, Wager (58) in Poly- 



