252 AQUATIC PHYCOMYCETES 



in diameter, with a lamellated wall like that of the sporangium, 0.7- 

 1 .3 a, thick, with a faint golden tint; contents of resting spore consisting 

 of one or more large central globules surrounded by a peripheral layer 

 of smaller globules; enveloped like the zoosporangium by one or several 

 halos, acting like a prosporangium upon germination, giving rise to 

 a hyaline zoosporangium 29-37 y. in diameter, which in turn is envel- 

 oped by a halo" (Hanson, loc. cit.). 



Saprophytic on grasses, bleached corn leaves, and cellophane, 

 United States. 



The curious "halo" developed by this species is indeed remarkable 

 and bears some resemblance to the gelatinous hull formed by the in- 

 completely known ? Rhizophydium gelatinosum Lind (p. 307) and the 

 planktonic parasite R. difficile Canter (p. 256). 



The developmental morphology and the cytology are discussed and 

 the species is figured in Hanson (1945b). 



Rhizophydium vampyrellae (Dang.) Minden 



Kryptogamenfl. Mark Brandenburg, 5: 320. 1911 (1915) 



Chytridium vampyrellae Dangeard, Le Botaniste, 1:63, pi. 3, figs. 14-16. 

 1889. 



Sporangium sessile, spherical, with a thickened smooth wall and 

 several subapical discharge papillae; rhizoids branched, arising from 

 a central somewhat thickened main axis; zoospores very narrowly 

 ellipsoidal or ovoidal when escaping through the pores formed upon 

 the deliquescence of the papillae, the conspicuous colorless globule 

 anterior or basal, the flagellum of moderate length; resting spore (?) 

 spherical, with a thick smooth wall and an apparently unbranched 

 rhizoid, germination not observed. 



On cysts of Vampyrella parasitizing colonies of Gloeocystis vesiculosa, 

 France. 



Considered doubtfully distinct from Rhizophydium globosum by 

 Dangeard. The zoospores were observed to become very constricted 

 and elongated when passing through the gelatinous layer of the col- 

 onies of Gloeocystis. Their shape during swimming evidently was 

 not observed. In Dangeard's explanation of Plate 3, "Figure 16c" is 



