HANSON: NEW CHYTRIDS 31 



82 p., ovoid, 17-63 x 28-97 /x, cylindrical, 6-15 x 19-75 /x, spherical, 17-57 //,, 

 elliptical, 21-62 x 37-159 fx, rectangular, 43-55 x 59-83 fi, triangular, 35-59 x 44- 

 65/a, or irregular, 26-67 x 35-193 fx, with 1-9 exit canals, 3.7-16 x 7.5-112 jx, 

 frequently branched, and of which only one functions. Tips of exit papillae or 

 canals softening at maturity and becoming filled with a plug of mucilaginous 

 material ; granular protoplasm receding downward and forming an operculum 

 beneath the plug. Opercula extremely thin, shallow saucer-shaped, circular or 

 oval in outline, 2.2-2.9 [x, in diameter. Zoospores spherical, 3.7-4.5 \x, with 

 many golden refractive globules, flagellum approximately 30 fx long, emerging 

 singly and forming a temporary group near the orifice, intermittently amoeboid. 

 Resting spores doubtful. 



Saprophytic on grasses, bleached corn leaves, onion, and cellophane, Sharon, 

 Connecticut. 



The second species is monocentric and Rhkophydium-like. The sporangia 

 and resting spores are surrounded by one or several hyaline zones or halos 

 which stand out very sharply when stained with ruthenium red or gentian 

 violet. The structure and development of this chytrid are fundamentally similar 

 to those of species of Rhizophydium, and for this reason it is included in this 

 genus under the name R. coronum nov. sp. 



Rhizophydium coronum sp. nov. — Zoosporangiis hyalinis, sphaericis, 

 11-49 p diametro, ovatis, 10-48 x 14-54 /x, cum muris laminatis, lamina externa 

 saepe prope superior sporangi dirupta ; una vel quinque papillis exeuntibus, 

 3-3.7 x 9-11 fi. Uno vel compluribus coronis concentricis sporangia evolventia 

 circumdantibus, uno maturitate reliquo ante sporarum dimissionem plerumque 

 deliquescente. Zoosporis hyalinis. sphaericis, 3.7-4.5 fx, cum uno magno globulo 

 refractivo, 1.5 ^ diametro, primis zoosporis cumulo emergentibus, post 6-14 

 horae sexagesimas partes devidentibus, reliquis in sporangio natantibus et 

 singillatim emergentibus. Rhizoidibus mediocriter rigidis, cum 1.5-4.5 fx muris 

 crassis, directis, tortuosis, minime vel maxime ramosis, uno saepe dominante 

 atque maxime extenso usque ad 500 jx longitudine. Spora perdurante sphaerica 

 vel subsphaerica, 22-35 /x diametro, cum muro lamellato sporangio simili, 

 0.7-1.3 /x crasso, pallido auro tincta. Spora perdurante unum vel plures magnos 

 globulos medios strato, peripherali globulorum minorum circumdatos con- 

 tinente. Zoosporangio simili uno vel compluribus coronis involuta, atque germi- 

 natione prosporangi modo se gerente, zoosporangio hyalino 29-37 [x diametro 

 oriente, quod deinde corono involvitur. 



Rhizophydium coronum nov. sp. — Zoosporangia hyaline, spherical 11-49 \x 

 in diameter, ovoid 10-48 x 14-54 fx, with laminated walls, outer lamina often 

 disintegrating around the upper half of the sporangium ; one to five exit papillae, 

 3-3.7 x 9-11 p. One to several concentric halos surrounding the developing 

 sporangia, reduced to one at maturity, which generally deliquesces before spore 

 discharge begins. Zoospores hyaline, spherical, 3.7-4.5 [x, with one large 

 refractive globule, 1.5 /x in diameter, the first zoospores emerging as a coherent 

 mass, separating after 6-14 minutes, the remainder swimming in the sporangium 



