514 AQUATIC PHYCOMYCETES 



swollen tip of the germ tube, where the resting body or zygote matures; 

 germination not observed" (Koch, he. cit.). 



Parasitic and weakly saprophytic on Vaucheria geminata, Koch (be. 

 cit.), United States. 



Chytridium sexuale Koch differs from C. cejpii Fott in the sporangia 

 being almost constantly bent or even twisted and in the ready develop- 

 ment of resting spores. Otherwise, the two are strikingly similar. See 

 "Sexual Reproduction," p. 79. 



Chytridium schenkii (Schenk) Scherffel 

 Arch. Protistenk., 54:237, pi. 10, figs. 125-129, pi. 11, figs. 130-132. 1926 



Rhizidium intestinum Schenk, pro parte, Ueber das Vorkommen contrac- 

 tiler Zellen im Pflanzenreiche, p. 5. Wiirzburg, 1858. 



Rhizidium schenkii Dangeard, Ann. Sci. Nat. Bot., VII, 4:297, pi. 13, 

 figs. 24-30. 1886. 



Phlyctochytrium schenkii (Dang.) de Wildeman, Ann. Soc. Beige Micro. 

 (Mem.), 20:48. 1896. 



Sporangium variable in shape, ovoid, ellipsoid, or pyriform, 15 \x 

 high by 10 [x in diameter, erect or procumbent, with a prominent apical 

 papilla surmounted by a smooth convex operculum 3 u, in diameter, 

 the colorless wall bearing a small lateral or basal colorless thick-walled 

 hemispherical protuberance (the persistent zoospore case), otherwise 

 thin and smooth; rhizoids branched, well developed in one or more 

 cells of the substratum, occasionally becoming extramatrical, arising 

 generally from the base of an endobiotic subsporangial spherical apophy- 

 sis 8-10 \x in diameter; zoospores spherical, 2-3 \x in diameter, with 

 a colorless eccentric or centric globule and a long flagellum, emerging 

 upon the dehiscence of the operculum and forming a motionless mass 

 possibly surrounded by a vesicle, after a period of rest assuming motility; 

 resting spore endobiotic, spherical, 10 (j. in diameter, colorless, with a 

 thick smooth wall and highly refractive oily contents, apparently without 

 rhizoids, at germination forming an epibiotic sessile narrowly ellipsoidal 

 erect or somewhat procumbent sporangium 15 u. high by 10 u. in diam- 

 eter, with a smooth colorless thin wall and an apical operculum 3[jl in 

 diameter, zoospores spherical, 2 \x in diameter, with a single globule 

 and a flagellum 10 \x in length. 



