310 AQUATIC PHYCOMYCETES 



SECTION II 



On Fresh-Water Algae 



? Rhizophydium (?) persimilis Scherffel 

 Arch. Protistenk., 54: 199, pi. 9, figs. 60-61. 1926 



Sporangium sessile, broadly pyriform, with a broad flat-arched 

 somewhat conical apex, 20-24 [j. high by 15-16.6 \x in diameter, wall 

 rather thick, smooth, colorless; endobiotic part not observed; zoo- 

 spores and method of sporangial discharge not observed; resting 

 spore (?) sessile, spherical, 8-12 \x in diameter, with a somewhat thick- 

 ened wall covered on its outer surface with small wartlike granula- 

 tions, contents with a large eccentric oil globule, germination not 

 observed; male cell spherical, 4-6 (x in diameter, wall smooth, thick, 

 attached laterally to the receptive thallus (resting spore). 



On Tribonema bombycina, Hungary. 



As Scherffel suggests, the resting spore is very much like that formed 

 by Rhizophydium granulosporum. The sporangia of the latter are, how- 

 ever, distinctly smaller than those associated with the present species. 

 Endogenous cysts belonging to an unknown parasitic organism were 

 found in the sporangia. 



? Rhizophydium pyriformis Valkanov 

 Arch. Protistenk., 73: 362, figs. 3-5. 1931 



Sporangium sessile, narrowly pyriform with a broad rounded apex, 

 broadly obpyriform or oblong with one constriction (rarely with two); 

 rhizoids branched, arising from the base of a broad penetration tube; 

 zoospores not observed, apparently escaping through a terminal open- 

 ing; resting spore not observed. 



Parasitic on ripe oospores of Vaucheria sp., Bulgaria. 



? Rhizophydium sp. Karling 



Bull. Torrey Bot. Club, 65: 451, pi. 21, figs. 18-33. 1938 



" Rhizophidium sp. occurs saprophytically on a wide variety of dead 

 filamentous and unicellular algae, flagellates, rhizopods, rotifers, liver 

 fluke ova and ovarian tissue, eggs, larvae and exuviae of insects, 



