992 AQUATIC PHYCOMYCETES 



trophied host parts; forming a single zoosporangium; zoospores var- 

 iable in number, reniform, 12 by 8 [x, laterally biflagellate, ejected in an 

 amorphous mass from the discharge tube to the outside of the host 

 where maturation is completed; resting spores asexually formed in a 

 series in branches of the thallus, rectangular or somewhat ellipsoidal, 

 10-15 by 8-12 [x, bearing numerous oil globules, wall thickened, ger- 

 mination not observed. 



Parasitic in hyphae and reproductive organs of Achlya sp., in soil, 

 Cuba. 



This species is remarkable for its virulence as a parasite. All parts of 

 the host are invaded and destroyed within a few days. Both zoospo- 

 rangia and resting spores are formed almost simultaneously. In early 

 stages of thallus development pronounced hypertrophy of the host is 

 evident, even though the parasite itself may be wholly or partly masked 

 by the dense contents of the infected area. Cross walls may or may not 

 be laid down by the host to wall off infection. The thalli converted into 

 zoosporangia discharge their contents through a short tube to the 

 outside, where the mass, apparently without an enveloping vesicle, 

 rapidly becomes converted into biflagellate zoospores. Other thalli by 

 cleavage of their protoplasm into uniform-sized irregular blocks pro- 

 duce asexually the thick-walled resting spores which undoubtedly survive 

 during periods of drought. 



Lagenidium oophilum Sparrow 



Mycologia, 31 : 532, figs. 1-15. 1939 



(Fig. 80 G-l, p. 987) 



Thallus when occurring singly somewhat irregularly saccate or 

 ellipsoidal, with broad lobes of varying length, when several, more 

 regularly ellipsoidal and often unlobed, converted holocarpically into 

 a single thin-walled colorless sporangium 20-40 [x long by 12-25 jx wide 

 with a short sessile or slightly prolonged discharge papilla 4-5 [x in 

 diameter; zoospores grape-seed-like, laterally biflagellate, 8 jx long by 

 6 [x wide, discharged individually and undergoing a period of maturation 

 in a group at the orifice of the discharge tube, apparently not surrounded 



