808 AQUATIC PHYCOMYCETES 



generally two, placed near one end; primary zoospores from fifteen to 

 eighteen, swarming within the sporangium, ovoid, 3 \x long, with a 

 single refractive granule and two equal subapical posteriorly directed 

 flagella longer than the body, encysting at the orifice in a group, cysts 

 3 \x in diameter, with a large refractive globule, secondary zoospores 

 not observed; resting spore not observed. 



Parasitic in Gomphonema micropus, Hungary. 



Differing from Ectrogella bacillariacearum primarily in having an 

 Achlya-likQ rather than a Saprolegnia-like type of spore discharge. 



Ectrogella licmophorae Scherffel 



Arch. Protistenk., 52: 10, pi. 1, figs. 22-30. 1925 



(Fig. 60 B-C, p. 806) 



Sporangium predominantly ovoid andolpidioid, occasionally irregu- 

 larly saccate, 7-25 \x long by about 7 \x in diameter (calculated), wall 

 smooth, thin except at the base of the discharge tube, where it is thicken- 

 ed to form a "forcing apparatus," discharge tubes from two to ten 

 (rarely one), slightly prolonged, broadly conical, often emerging from 

 opposite sides and giving a starlike appearance; primary zoospores 

 pyriform, 3 [i long, with two apical posteriorly directed flagella, assum- 

 ing motility within the sporangium, upon emergence encysting in a 

 group at the orifice of the discharge tube, cysts 3.5 a in diameter, 

 secondary zoospores not observed; oospore (one instance) subspherical, 

 12 fx in diameter, with a thick smooth colorless wall, contents with large 

 irregular fat clods, not filling the oogonium, the latter spherical, thin- 

 walled, 14 [i. in diameter, germination not observed; antheridium 

 consisting of a single saclike structure almost equal in size to the oogo- 

 nium, attached to the latter by a narrow tube. 



Parasitic in Licmophora sp., Italy (the Adriatic, near Rovigno). 



Ectrogella licmophorae occurs in the same host as E. perforans. It 

 differs from Petersen's species in several particulars but primarily in the 

 encystment of the zoospores after discharge, the presence of the "forcing 

 apparatus," the more irregular shape of the sporangium, and the fact 

 that the oospore lies loose in the oogonium, to which the saccular 

 antheridium is attached by a beaklike process (Fig. 60 B, p. 806). 



