938 AQUATIC PHYCOMYCETES 



zoospores ellipsoidal or somewhat elongate, provided with an anterior 

 and a lateral flagellum; resting spore spherical, 51-73 \x in diameter 

 (without the spines), with a thickened dark or silvery wall, the outer 

 surface covered with numerous hyaline rodlike sharp-pointed spines 9.6 

 (x long, germination not observed; companion cell spherical, 25.2-32.4 u, 

 in diameter, with a thin wall, the outer surface densely covered with 

 long rodlike sharp spines. 



Parasitic in hyphae of Achlya flagellata, sometimes occurring with 

 "Pseudolpidiumfusiforme" and "Olpidiopsis minor;' Japan. 



Olpidiopsis incrassata Cornu 

 Ann. Sci. Nat. Bot., V, 15: 146, pi. 4, fig. 12. 1872 

 Pseudolpidium incrassata (Cornu) Fischer, Rabenhorst. Kryptogamen- 



Fl 1(4): 37. 1892. 

 (?) Olpidiopsis major Maurizio, Jahresbericht Naturforsch. Gesell. Graub- 



iindens, Chur, 38: 15, pi. 1, figs. 4-9. 1895. 

 (?) Olpidiopsis vexans Barrett, Ann. Bot. London, 26:231, pi. 23, ngs. n, 

 19-21, pi. 24, figs. 26-27, 32-39, pi. 25, figs. 40-42, 44, 47-71, pi. 26, 

 fig. 75. 1912. 

 Sporangium ellipsoidal or subspherical, wall thin, smooth, colorless, 

 discharge tube single, stout or narrowly cylindrical; zoospores not 

 observed; resting spore ellipsoidal, yellowish brown, with a thick 

 strongly undulating wall, germination not observed. 



Parasitic in Achlya racemosa, Cornu (be. cit.), France; Achlya sp., 

 Sparrow (1933c: 515), United States. 



Sorokhrs fungus (1883:29, fig. 29) referred to this species is not 



identifiable. 



Only one doubtful instance of a companion cell on a resting spore 

 was noted by Cornu. His fungus, consequently, was referred to Pseud- 

 olpidium by Fischer. The resting spores observed by Sparrow were 



nearly colorless. 



Shanor (1940) indicated that he would present evidence to prove 

 that Olpidiopsis major Maurizio and O. vexans Barrett are synonymous 

 with Cornu's species. His experimental work shows, however, that the 

 material on which he based his study is confined to Saprolegnia. This 

 agrees with the findings of Maurizio and Barrett, but is contrary to the 



