172 AQUATIC PHYCOMYCETES 



The record of this fungus in Pythium monospermum attributed by 

 Karling (1942b: 198) to Tokunaga (1933b) is apparently an error. 



Whether or not the parasite of Pythium with spherical zoospores 

 '-9 [j. in diameter, which emerge from one to several pores, reported 



from China by Shen and Siang (1948: 181), should be placed here 



seems doubtful. 



ROZELLA CANTERAE, sp. IIOV. 1 



Sporangium assuming the shape of the unhypertrophied host spo- 

 rangium and completely filling it; zoospores ovoid, with a small re- 

 fractive anterior globule and posterior flagellum, escaping after the 

 operculum of the host is dehisced; resting spore somewhat ovoid, with 

 a thick wall, the outer wall of which bears hexagonal ridges and spines. 



Parasitic in sporangia of Chytridium oedogonii (Canter), Great 

 Britain. 



The species is based on the observations of Canter (1950d: 357, 

 fig. 3, g-n, pi. 29, figs. 4-5) of an unnamed Rozella. 



Rozella chytriomycetis Karling 

 Mycologia, 38: 107, figs. 9-19. 1946 



"Sporangia solitary, hyaline, filling host cell and conforming with 

 the latter in size and shape, usually spherical, 10-40 \x, with one to 

 three exit papillae; wall of sporangium usually indistinguishable from 

 that of host cell. Zoospores hyaline, oblong or slightly clavate, 3 x 

 1.5 [i, with a minute, .5-7 ;i., refractive globule; swirling in sporangium 

 before emerging; darting about rapidly in swimming, rarely becoming 

 amoeboid. Resting spores partly or almost completely filling host cell, 

 oval or spherical, 7—20 ;jl, with large central vacuole, and coarsely 

 granular cytoplasm; wall dark brown, rarely smooth, usually spiny 

 or echinulate; germination unknown" (Karling. he. cit.). 



Parasitic in Chytriomyces hyalinus, United States. 



1 Rozella canterae, sp. nov. -- Sporangium ad formam sporangii hospitis nor- 

 mal is exacte conformans. Zoosporis ovoideis. globulo anteriori parvo et flagello 

 posteriori pracditis, delapsu hospitis operculi liberatis. Sporis perdurantibus subo- 

 voideis, crasse circumvallatis, extus hexagonaliter costatis, spinosis. 



Parasitica in sporangiis Chytridii oedogonii, Gri at Britain. 



