CHYTRIDIALES 555 



to form a foot; operculum shallow, saucer-shaped, 6-12 u, in diam. 

 Zoospores oval, 5 X 6.5-7.5 \x, with a refractive globule 3 u, in diam. 

 near posterior end; flagellum 25-28 u, long; zoospores swarming in a 

 hyaline vesicle outside of sporangium for 2-8 minutes before breaking 

 out and swimming away; vesicle continuous with interior of sporan- 

 gium. Rhizoids arising as a tuft of fine threads from base of thallus and 

 extending for a distance of 200 \l; threads simple or branched. Resting 

 spores unknown" (Karling, he. cit.). 

 Saprophytic on exuviae, Brazil; exuviae {he. cit.), United States. 



CATENOCHYTRIDIUM Berdan 



Amer. J. Bot., 26:460. 1939 



(Figs. 8 A-E, p. 97; 33 A-B, p. 564) 



"Thallus intra- and extramatrical, predominantly monocentric,eucar- 

 pic. Zoosporangium extramatrical, operculate, delimited by a cross wall 

 at maturity. Development of zoosporangium endo-exogenous. Apoph- 

 ysis intramatrical, [usually] compound, consisting of linear series of con- 

 stricted, catenulate segments subtended by an extensive, richly branch- 

 ed rhizoidal system. Zoospores posteriorly uniciliate, emerging in a 

 globular mass and lying quiescent for a few moments before swimming 

 away; method of swimming rapid and darting. Resting spore extra- 

 matrical, usually formed in the same position as the zoosporangium, a 

 segment of apophysis sometimes encysting and becoming a resting 

 spore; germination unknown" (Berdan, he. cit.). 



Explanation of Figure 32 



A. Truittella setifera Karling, thallus on cellulosic substratum showing 

 central operculate sporangium, main axes of rhizoidal system, and zoospore 

 cyst bearing setae. B. Rhopalophlyctis sarcoptoides Karling on insect exuviae, 

 empty basally septate sporangium. C. Karlingiomyces dubius (Karling), comb, 

 nov., on chitinous substratum. D. Chytriomyces spinosus Fay on vegetable 

 debris, discharging sporangium. E-F. Chytriomyces aureus Karling on insect 

 exuviae: E, empty epibiotic sporangium; F, epibiotic resting spore. G. Cylin- 

 drochytridium johnstonii Karling in vegetable debris, discharging sporangium. 



{A, Karling, 1949b; B, E-F, 1945c; C, 1949e; D, 1947d; C, 1941a) 



