242 AQUATIC PHYCOMYCETES 



Only one (apical) pore was observed in the sporangia of Sparrow's 

 material, whereas Couch reports one or several in his fungus. This 

 difference is not considered of great significance in view of the striking 

 similarities which are otherwise apparent in the two fungi. Germination 

 of the resting spores of material which is probably this species has 

 been described by Karling (1939c) (Fig. 17 I, p. 228). 



Rhizophydium canterae, sp. nov. 1 



Sporangium sessile, spherical, with a smooth, thin, colorless wall, 

 7.5-34.3 \L in diameter, the larger ones occurring singly on the ab- 

 normally curved host cell, the smaller ones gregarious, up to fourteen 

 on a single cell; endobiotic part consisting of a sparingly branched 

 rhizoidal system arising from a short, rarely slightly inflated main 

 axis; zoospores somewhat elongate, 4 \x long by 2 [x in diameter, lacking 

 a conspicuous globule but bearing one or two minute, highly refractive 

 granules laterally placed near the point of attachment of the single 

 posterior flagellum, escaping upon the deliquescence of a single, con- 

 spicuous lateral papilla; resting spores spherical, asexually formed, 

 21.4-35 u. in diameter, with a 2 \x thick, smooth wall, contents oily, 

 rhizoids and germination not observed. 



Parasitic on sporelings of Oedogonium sp., Scherffel (1926a: 230, 

 pi. 10, figs. 116-117), Hungary; same host, Canter (1947b: 96, fig. 

 2, pi. 9), Great Britain. 



The species is based on Scherffers observations and, in particular, 

 on those of Canter. It bears some resemblance to Rhizophydium kar- 

 lingii, except that it differs in having zoospores without a conspicuous 

 globule and in certain other features. 



1 Rhizophydium canterae sp. nov. — Sporangia sessilia, sphaerica, membrana 

 tcnui, incolorata, 7.5-34.3 [j. diam., majora singula in abnormaliter curvatis hospitis 

 cellulis posita, cetera minora gregaria (usque ad 14) in cellula hospitis una. Pars 

 endobiotica ex axi primario brevi rare inflato et ramis rhisoideis paucis constans. 

 Zoosporae breviter elongatae, 4 \i longa, 2 \x diam., sine globulo conspicuo, sed 1 vel 

 2 granula refractiva lateralia prope flagellum singulum posticum includentes, libe- 

 ratae per papillam singulam conspicuam lateralem deliquescentem. Sporae per- 

 durantes globosac, asexualiter originatae, 21.4-35 jjl diam., membrana crassa, laevi; 

 intus oleaginosae; rhizoideis germinationeque nondum observatis. 



Ab auctore non visum, sed fundatum ex observationibus ell. Scherffelii et (prae- 

 cipuc et typice) Canterae. Rhizophidio lateral! similis sed difleri zoosporis sine globulo 

 conspicuo notisque ceteris. 



Parasitica in Oedogonium sp., Hungary and Great Britain. 



