CHYTRIDIALES 459 



on the prosporangium, the shape of the sporangium, and the motile 

 spores. 



ENDOCOENOBIUM Ingold 



New Phytologist, 39: 97. 1940 

 (Fig. 29 A-B, p. 450) 



"The thallus is microscopic, living within the coenobium of members 

 of the Volvocales. From the sac-like thallus rhizoidal outgrowths, 

 branched or unbranched, make contact with the host cells. The thallus 

 is not produced by the direct enlargement of the encysted zoospore, 

 but by the enlargement of an outgrowth from it. The encysted zoospore 

 persists on the surface of the host coenobium. The zoosporangium is 

 elongated, and cut off from the thallus by a cross wall. Dehiscence is by 

 an apical tear. The zoospores are uni-ciliate. The thick-walled resting 

 spores are produced following a sexual process. In this process two 

 thalli, which have developed in the same coenobium, fuse, and from 

 the fusion-cell a warted zygospore is budded off" (Ingold, loc. cit.). 



On Eudorina elegans, Great Britain. 



A monotypic genus. 



ENDOCOENOBIUM EUDORINAE Ingold 



New Phytologist, 39: 97, figs. 1-4, pi. 2. 1940 



Sporangium 48-64 \i long by 18-36 \x in diameter; zoospores 50-200 

 in a sporangium, subspherical, 4-5 pi in diameter, with a refractive 

 eccentric globule; resting spore 15-30 \i in diameter with its outer wall 

 covered by low spines. 



Parasitic on the plankton alga Eudorina elegans, Ingold (loc. cit.), 

 Great Britain; Eudorina elegans, Jaag and Nipkow (1951 : 494, pi. 16), 

 Switzerland. 



In the Swiss material up to 10 per cent of the colonies observed were 

 infected. 



Since the thallus develops as an outgrowth from the zoospore, Canter 

 believes this fungus should be placed near Entophlyctis. Because of the 

 formation of a prosporangium, however, it seems closer to Polyphagus 

 and is maintained in the same subfamily for the present. 



