98 ILLINOIS BIOLOGICAL MONOGRAPHS [336 



Spore: Generally circular in front view; oval in side view. Shell com- 

 paratively thick, consequently the coiled polar filament is frequently indis- 

 tinct. Sutural ridge straight and distinct. Each valve has a thick straight, 

 sometimes slightly zigzag-form ridge that runs parallel to the sutural line, 

 so that in side view, three distinct ridges encircling the spore are recognized 

 (Figs. 177 and 180), From each of these two ridges, eight to twelve short 

 ridges are directed toward the center of each valve, which can distinctly 

 be observed on the spores stained with Heidenhain's iron hematoxylin 

 (Figs. 179 and 180). They can be seen as faint markings rising from the 

 margin directed toward the center of the spore, in front view of fresh spores. 

 Four pyriform polar- capsules of slightly different size open their foramina 

 independently at the anterior end of the spore (Figs. 178 and 181). The 

 sporoplasm, granular and finely reticular, shows almost always two nuclei 

 when stained. Dimensions in vivo: length and breadth 8 to 10/i, thickness 

 5 to In, polar capsules 3 to Sn by 2 to 3/x, length of polar filament 32 to 

 40/i (H2O2, KOH). 



Remarks: In carefully made smear of the bile, a number of empty 

 spores which had been seen in fresh hanging drop preparations, and often 

 spores, in which the sporoplasm with two elongated nuclei seemed to leave 

 the shell (Fig. 182), were recognized. As this particular spore was found 

 close to a thicker mass of the wall of the gall-bladder in the smear, it can 

 hardly be thought that the mechanical pressure during the preparation 

 lead to the mission of the sporoplasm from the spore. It is possible, on the 

 other hand, to think that this is one of the cases of the germination of the 

 spore in the host in which they were developed, as was reported by the 

 author in Nosema bombycis Nageli (Kudo, 1916). 



CHLOROMYXUM CATOSTOMI nov. spec. 

 [Figs. 560 and 561] 



Habitat: Gall-bladder of Catostomus commersonii Lac; Salt Fork, 

 Urbana, 111. (October). Four fish, from 8 to 14cm.; apparently normal. 



Vegetative form: Form usually rounded, with fiUform pseudopodia. 

 Majority attached to the epithelium, a few being free in the bile. Body 

 colorless. Protoplasm is not well differentiated. Endoplasm occupying 

 the entire body is of granular structure with vacuoles and refringent 

 spherules. Size: from 15 to 35)li. When kept for 16 hours in a refrigerator, 

 the trophozoites liberated the spores. The number of spores in each tro- 

 phozoite is usually 2 or 3, rarely 5 to 6. Active plasmotomic multiplication 

 observed when examined. Spores were comparatively small in number, 

 while the trophozoites were attached abundantly to the epithehum of the 

 gall-bladder. Disporous and polysporous. 



Spore: Form approximately spherical in front view; oval in profile. 

 Shell with very fine striations which run parallel to the sutural ridge that 

 is fairly well marked. Rounded polar capsules almost of same size, have 



