CHYTRIDIALES 289 



8-10 [i high; rhizoid unbranched, 1 u, in diameter; zoospores formed 

 in large numbers, spherical, 3 (x in diameter, with a colorless globule 

 1 [x in diameter and a long flagellum, released upon the deliquescence 

 of the entire upper half of the sporangium wall, movement hopping 

 or amoeboid; resting spore (?) sessile, subspherical, with a flattened 

 base, 8 \x in diameter, wall thick, smooth, colorless, contents with a 

 colorless refractive oil globule, 5 [jl in diameter, endobiotic part en- 

 closed in a plug of host wall material, germination not observed. 



On moribund diatoms, Cymatopleura elliptica, C. solea, Nitzschia 

 sigmoidea, Cymbella, Navicula sp., Scherffel (loc. cit.), Hungary; 

 Cymbella ospera, Friedmann (1952: 182, figs. 2m, n), Austria. 



The resting spores, found only on Nitzschia sigmoidea, have not 

 been related with certainty to the sporangial stage. 



The species resembles Podochytrium in the possession of a poorly 

 defined fertile basal region on the sporangium, and may ultimately 

 be referred to this genus. It differs from P. emmanuelensis in its method 

 of spore discharge, that is, discharge by the deliquescence of the 

 upper part of the sporangium, and in having a smooth-walled resting 

 spore. 



Rhizophidium fulgens Canter 



Ann. Bot. London (N.S.), 15: 144, figs. 9-11, pi. 11. 1951 



(Fig. 10 L, p. 108) 



"Thallus monocentric eucarpic, consisting of a sporangium devel- 

 oped from the encysted zoospore, an unswollen stalk-like region within 

 the mucilage envelope of the alga, and a branched rhizoidal system 

 inside the host cell. The sporangium varies in shape from obovate to 

 oval (6 [i high X 4.5 [x broad to 10 [j. high x 8 u. broad) and contains 

 from 4 to 18 zoospores. The zoospores (2.5^. in diameter) are ante- 

 riorly uniguttulate and posteriorly uniflagellate; they escape from the 

 sporangium via two pores formed in the apical corneis of the wall. 

 Resting spore asexually formed, oval in shape (6 y. high x 4.5 [i broad 

 to 8 [i high x 6 [j. broad) with a smooth, thick, colourless wall. The 

 content contains numerous small peripheral refractive globules and 

 one or two larger globules. On germination functioning as a prospo- 

 rangium" (Canter, loc. cit.). 



