188 AQUATIC PHYCOMYCETES 



discharge tube, ultimately swimming away, sometimes assuming mo- 

 tility directly after emergence. 



Parasitic in Synedra sp., Great Britain. 



BICRICIUM Sorokin 



Arch. Bot. Nord France, 2: 37. 1883 (separate) l 



(Fig. 15 1-J, p. 186) 



Thallus endobiotic, holocarpic, at maturity divided into two seg- 

 ments separated from each other by a narrow septate isthmus; spo- 

 rangia inoperculate, one sporangium formed from each of the segments, 

 each bearing a single discharge tube; zoospores posteriorly uniflagel- 

 late; resting spore thick-walled, formed in a segment of the thallus. 



In fresh- water green algae and eelworms. 



The genus has been rejected by Fischer (1892), Minden (1915), 

 Karling (1942e), and others, being considered by them to be based on 

 two-celled forms of Myzocytium. Scherffel (1926a: 213), however, 

 points out that, in contrast to Myzocytium, uniflagellate zoospores 

 are formed in Bicricium. He further implies that in the formation of 

 the resting spore no sexuality is involved, since one of the two thalli 

 opens to the outside and probably is a sporangium. If the fungus were 

 a species of Myzocytium this thallus would ordinarily function as an 

 antheridium. The argument is weakened here, however, by the fact 

 (not mentioned by Scherffel) that the "oogonium" also possesses an 

 open tube (Sorokin, op. cit., fig. 46). 



The proper disposition of the genus is still a matter of doubt. Enough 

 is known about it, however, to place it in the Achlyogetonaceae near 

 Achlyogeton and Septolpidium. 



Bicricium lethale Sorokin 

 Arch. Bot. Nord France, 2: 37, fig. 45. 1883 (separate) 2 

 (Fig. 15 J, p. 186) 

 Sporangia irregularly narrowly ellipsoidal, strongly constricted at 

 the thin cross wall which separates them, each of the free ends pro- 



See also Sorokin, Revue Mycologique, 11: 1 38. pi. 81, fig. 119 1889 

 ' Ibid., pi. 83, tigs. 72-74. 1889. 



