412 AQUATIC PHYCOMYCETES 



walled resting spore which produced upon germination sporangia more 

 like those of the nonsexual phase than did the hairy ones. Moreover, 

 he failed to mention the basipetalous sporangial renewal, which is 

 suggestive of a species of Nowakowskiella. Since Karling himself saw 

 no resting spores and since Nowakowski figured two types, neither of 

 which apparently occurred simultaneously with the sporangial stage, at 

 best the concept of R. nowakowskii remains confused and synthetic. 

 Whether the two types of resting spores actually represent two different 

 species needs further proof. If the species is based on a mixture, it 

 should be rejected. 



Rhizidium chitinophilum, sp. nov. 1 



Sporangium spherical or subspherical, 28-50 u, in diameter, with a 

 smooth wall, colorless, appearing as a lateral outgrowth from the 

 usually expanded proximal portion of the rhizoidal axis; rhizoidal 

 system consisting of a stout main axis from which emerge branched 

 rhizoids, its proximal portion somewhat expanded and forming an 

 apophysis delimited by cross walls; zoospores spherical, 4 jj. in diameter, 

 or ellipsoidal and 5 u, long by 3 jj. wide, with a single (rarely two) 

 conspicuous, laterally placed, colorless globule and a flagellum, 30-33 [x 

 long, emerging from a subapical or lateral pore in a compact sub- 

 spherical mass, the individuals at first motionless but shortly under- 

 going a period of collective swarming, probably within a vesicle, during 



1 Rhizidium chitinophilum, sp. nov. — Sporangium globosum vel subglobosum, 

 28-50 [x diam., laeve, pellucidum, latcraliter ex parte axis rhizoidalis proxima oriens. 

 Systema rhizoidale ex axe centrali et rhizoideis ramosis constans, parte proxima 

 paulum expansa, apophyin inter septa transversalia formante. Zoosporae globosae, 

 4 y. diam., vel ellipsoidales, ca. 5 \j. longae, 3 y. latae, emergentes ut massa compacta 

 subglobosa, denique soluta; primum immobiles sed cito (probabiliter in vesicula) 

 gregatim natantes et ad ultimum separatim dispersae, globulo singulo (raro 2) 

 conspicuo excentrico pellucido; rlagello 30-33 ijl longo ex poro subapicali vel laterali 

 protruso. Spora perdurans nondum visa. 



Saprophytum in cxuviis insectorum familiarum Ephemeridarum et Chironomi- 

 darum. United States, praecipue lectum prope locum dictum, "Clark's Pond, Canaan, 

 New Hampshire," anno 1937, primo descriptum sub nomine Rhizidio mycophilo 

 A. Braun, sed species distincta est. Figurae collectionis typicae in Proc. Amer. 

 Phil Soc, 78: tab. 2. 



