76 ILLINOIS BIOLOGICAL MONOGRAPHS [314 



flattened. Ends of valves sharply pointed. Polar capsules large, opening 

 at some distance from the anterior margin. Coiled polar filaments dis- 

 tinct. Sporoplasm finely granular usually extending farther into one valve 

 than the other. Dimensions: breadth between points of greatest curva- 

 ture about 16/11, sutural diameter 8 to 9/i, diameter of polar capsules 4.5/*. 



CERATOMYXA LUNATA Davis 



[Figs. 57 to 60] 



1917 CeraUmyxa lunata Davis 1917 : 226-227 



Habitat: Gall-bladder of Galeocerda tigrinus; Beaufort (August). 



Vegetative form: Pyriform, rounded after being on the slide for some 

 time. Progressive movements slow Endoplasm filled with large, homo- 

 geneous spherules, which are usually colorless, sometimes light yellow. 

 At extreme anterior end, the endoplasm contains numerous small fat 

 globules. Disporous. 



Spore: Considerably variable in size and form. The larger and more 

 typical are more or less crescent-shaped; symmetrical; valves curved 

 toward rear, terminating in more or less rounded ends. Polar capsules 

 large and open on opposite sides of spore. Coiled polar filament distinct. 

 Sporoplasm finely granular, symmetrically situated in spore. Smaller 

 spores differ from large ones chiefly in size; valves are much shortened 

 and have a greater curvature, with more distinctly rounded ends. Dimen- 

 sions: breadth 30m (longest 38^), sutural diameter 9/i, diameter of polar 

 capsules 4/*, length of polar filament 37/*. Small forms: breadth 15/*, 

 sutural diameter 7/*, diameter of polar capsules ^n. 



CERATOMYXA ABBREVIATA Davis 

 [Fig. 61] 

 1917 Ceratomyxa abbreviala Davis 1917 : 227 



Habitat: Gall-bladder of Scoliodon terrae-novae; Beaufort (August). 



Vegetative form: Elongate, pyriform, with usually a very long, slender 

 posterior process. Body colorless. Progressive movements rapid. Dis- 

 tinct differentiation of protoplasm, posterior process usually composed of 

 ectoplasm (rarely endoplasm may extend into it for a short distance). 

 Pseudopodia, short, tapering or filiform at anterior end. Dimensions: 

 length up to 90/*, breadth 10 to 12/*, diameter of rounded sporulating 

 trophozoites about 27/t. Disporous. 



Spore: Roughly crescent-shaped; sutural diameter exceptionally 

 great in comparison with the breadth. Ends of valves ^rounded, slightly 

 asymmetrical. Shell exceptionally tough and resistant to reagents. Polar 

 capsules large, prominent and open on opposite sides of spore. Sporoplasm 

 finely granular, confined entirely to one valve. Dimensions: breadth 17/*, 

 sutural diameter 14/*, diameter of polar capsules 4.5/*. 



