CHYTRIDIALES 525 



dealing with qualitative and quantitative changes occurring in the fungus 

 on different substrata, will eventually have to be made for all species 

 of the order, before a really comprehensive taxonomic treatise can be 

 prepared. 



A curious conjugation of encysted zoospores with young thalli devel- 

 oping in pure water was observed (Sparrow, he. cit.). After the contents 

 of the quiescent spore had evacuated the cyst and had flowed into the 

 receptive thallus, the latter underwent a remarkable vegetative develop- 

 ment, which in some cases appeared to terminate in the production of 

 a dwarf sporangium. The result of this fusion was not the formation of 

 a resting structure, as might be expected, but the rejuvenation of 

 vegetative growth and the prolongation of the life of the organism. 

 These thalli continued their growth for nearly a week and became very 

 extensive in contrast to ordinary germinating zoospores, which under 

 the same conditions disintegrated within twelve hours. 



Both Sparrow and Karling have observed the apparently asexually 

 formed resting spores, which, as the latter investigator points out, are 

 merely enlarged and encysted apophyses. Karling also observed their 

 germination, in which process the resting spore functioned as a prospo- 

 raneium. 



Chytridium lagenaria Schenk var. japonense Kobayasi and Ookubo 

 Bull. Nat. Sci. Mus. (Tokyo), 33: 56, figs. 3-A, 3-B. 1953 

 Sporangia gregarious on the surface of the host cell, sessile, ovoid, 

 globose or pyriform, rather thin-walled, 7-18 [x high, 6-15 \x in diameter, 

 hyaline, with an apical papilla, apical pore 5 \i in diameter, opening 

 by the dehiscence of a convex smooth operculum; apophysis connected 

 with the sporangium by a short and narrow neck, napiform or sub- 

 spherical, about the same size as the sporangium or smaller, 7-15 fj. in 

 length, 6-9 [j. in diameter, hyaline, homogeneous or somewhat granular; 

 rhizoids rather stout, two or three originating from the base of the apoph- 

 ysis, branched, 2-4 u. in diameter at the point of origin; zoospores 

 spherical or ovoid, hyaline, 2-3 \x in diameter, with 2-3 globules, a 

 refractive body and a posterior 10-12 u, long flagellum, emerging 

 through a pore one by one and swimming away; resting spore not ob- 

 served. (Modified from Kobayasi and Ookubo.) 



