1 3 8 AQUA TIC PH YCOM YCETES 



eter, with a single basal oil droplet and a long delicate posterior 

 Bagellum, motion hopping; resting spore spherical, 8-12 \x in diameter 

 with a thickened wall the outer surface of which bears a few straight 

 faintly refractive rodlike spines, germination not observed. 



On Hyalotheca dissiliens, H. mucosa, Scherffel (loc. cit.), Hungary; 

 //. dissiliens, Canter (1949b: 22, fig. 1 a, 2), Great Britain; Desmid- 

 ium swartzii, Sparrow and Barr (1955: 553), United States. 



Olpidium saccatum Sorokin 



Arch. Bot. Nord France, 2: 30, fig. 33 a-d. 1883 (separate) * 

 (Fig. 13 C, p. 136) 



Sporangium swollen and short sausage- or saclike, smooth, thin- 

 walled, constricted in the mid-region, with a somewhat conical end 

 resting against the inner surface of the host cell and by means of a 

 circular pore opening at the level of the outer host wall to the outside 

 at maturity, or, if the sporangium body does not directly make con- 

 tact w ith the wall, forming a short, or rarely elongate and bent, sharply 

 defined cylindrical discharge tube the open apex of which is just level 

 wiih the outer surface of the host wall but never extends beyond it; 

 zoospores minute, typically chytridiaceous with the characteristic oil 

 droplet; resting spore apparently asexually formed by contraction of 

 the protoplasm of the thallus, nearly spherical or somewhat pyriform, 

 colorless, 11-16 (i, in diameter, mostly 14-15 \x high by 16 jx in diam- 

 eter, wall about 2 \x thick, the outer layer appearing dark and of 

 double contour, the inner faintly refractive contents with a densely 

 crowded group of strongly refractive (oil?) coarse granules or with 

 a single large fat droplet, the spore lying in the spherical widened end 

 of the thin-walled tube, from which it is separated by a cross wall, 

 germination not known. 



In desmids, Sorokin (loc. cit.), Asiatic Russia; Cosmarium sp., de 



Wildeman (1893b: 50, pi. 6, figs. 17-25), Belgium; Siaurastnim sp., 



Cosmarium sp., coil. Massart, de Wildeman (1896b: 46, pi. 3, figs. 



\2), Norway, France; Cosmarium botrytis, Cosmarium sp., Scherffel 



(1926a: 210, pi. 10, figs. 80-83), Hungary; Micrasterias truncata, 



Sec also Sorokin, Revue Vfycologique, 11: 136, pi. 79, figs. 86-89. 1889. 



