CHYTRIDIALES 185 



panion cell, were probably formed by a species of Olpidiopsis para- 

 sitizing the sporangia of the Achlyogeton. The resting cells found by 

 Martin were possibly of similar origin, although in this instance either 

 the companion cell had disintegrated or the spore was formed asexually. 



IMPERFECTLY KNOWN SPECIES OF ACHLYOGETON 



? Achlyogeton (?) rostratum Sorokin 

 Ann. Sci. Nat. Bot., VI, 4: 64, pi. 3, figs. 40-45. 1876 * 



Sporangia ten or more, slightly constricted at the thin cross walls, 

 individuals ellipsoidal or somewhat irregular, 7-9 jj. long by 5-6 u, 

 wide, wall smooth, slightly thickened, discharge tube arising from the 

 mid-region of the sporangium, long, often somewhat tortuous, ex- 

 panded where it makes contact with the inner wall of the substratum 

 and penetrating the latter with a short narrow tube; zoospores and 

 resting spore not observed. 



In Anguillula, Sorokin (be. cit.), European Russia; filaments of 

 "Conferves" Sorokin (1883:38, fig. 49), European Russia, Asiatic 

 Russia. 



Sorokin was uncertain of the generic disposition of his fungus. 

 Fischer (1892) and Minden (1915) have supposed it to be a Myzo- 

 cytium, probably because of the presence of a swelling on the basal 

 part of the discharge tube. The figure given in Sorokin's (1883) paper 

 shows the thallus to be nearly devoid of constrictions. 



? Achlyogeton salinum Dangeard 

 Le Botaniste, 24: 240, pi. 24, figs. 1-3. 1932 



Sporangia in chains of six or more, ellipsoidal, with a single dis- 

 charge tube. 



In Cladophora sp. (marine), France. 



From the figures given, the fungus is very probably Sirolpidium bry- 

 opsidis, which is occasionally found in Cladophora. Dangeard thought 

 it might prove to be a species of Myzocytium, but this is unlikely since 

 the thallus is successively divided into sporangia and the zoospores 

 are completely formed within the sporangium. 



1 See also Sorokin, Revue Mycologique, 11: 138, pi. 81, fig. 119. 1889. 



