CHYTRIDIALES 523 



large apical pore formed upon the dehiscence of a convex smooth oper- 

 culum and collecting at the orifice in a temporarily motionless mass, 

 movement swimming or amoeboid; resting spore spherical or ovoid, 

 18-30 \x in diameter, with a smooth colorless wall 2-3 \x thick, the 

 contents with a single large colorless globule, rhizoidal system like that 

 of the sporangium, upon germination forming an epibiotic sessile ovoid, 

 subspherical, somewhat flattened, or pyriform operculate sporangium. 



On Nitellaflexilis, Schenk (loc. cit.), Germany; Vaucheria sp., Dang- 

 eard (1889b: 64, pi. 3, fig. 23), France; Spirogyra sp., Cladophora sp. 

 (?), de Wildeman (1890: 14, fig. 4), Belgium (?); Oedogonium sp. (?), 

 Constantineanu (1901: 383), Rumania; Spirogyra sp., Cladophora sp., 

 Massee (1891: 155, pi. 2, figs. 36-37), Rhizoclonium hieroglyphicum, 

 Sparrow (1936a: 432, pi. 16, figs. 1-24), zygospores of Spirogyra sp., 

 dead cells of Cladophora sp., Canter (1953:292), Great Britain; 

 Oedogonium sp., Karling (1936a: 619, figs. 1-2; 1948c: 508), Cladophora 

 sp., Sparrow (1943: 348), United States ; Cladophora sp., Berczi(1940: 

 84, pi. 2, figs. 25, 26), Hungary; moribund cells of Spirogyra sp., Spar- 

 row (1952b: 69, figs. F-G), Cuba. 



The records of de Wildeman and Constantineanu are open to question 

 since no operculum was seen. Their fungi may in reality be Phlyctochy- 

 trium lagenaria (Schenk) Domjan. Rhizidium westii Massee is consid- 

 ered doubtfully synonymous with Chytridium lagenaria. It resembles 

 the latter in all observed essentials. No operculum was seen, but this 

 may have been overlooked by Massee. Even if it had not been, his 

 fungus still cannot, because of differences in the shape of the sporangium 

 and the stoutness of the rhizoidal system, be referred to Phlyctochytrium 

 lagenaria. 



Chytridium lagenaria has been the object of rather intensive inves- 

 tigation (Sparrow, 1936a; Karling, 1936a) and a relatively large amount 

 of data have been accumulated on its development and biology. 



The fungus was transferred from Rhizoclonium to Spirogyra sp. and 

 Oedogonium sp. to determine any morphological changes which might 

 occur on these substrata (Sparrow, loc. cit.). It was found, under the 

 conditions of the experiments (conducted in van Tieghem cells), that (1) 

 the size and nature of the zoospore remained constant on the three 

 algae; (2) an endobiotic apophysis was always formed and, though 



