182 ILLINOIS BIOLOGICAL MONOGRAPHS [420 



32 {ii) Shell-valves shorter (sutural diameter : breadth = 1:1.6) 



Ceralomyxa coris Georgevitch 1916 • , (72) 



33(32) Shell- valves longer (sutural diameter: breadth = 1 :2 . 6) 



Ceratomyxa herouardi Georgevitch 1916 (72) 



34(23) Shell-valves asymmetrically built 35 



35(40) Spore arch-shaped in front view 36 



36(37) Sutural diameter equal to one-fifth of breadth; sutural diameter lO^u, breadth 

 50m 



Ceratomyxa globulifera Thelohan 1895 (67) 



37(36) Sutural diameter more than one-fifth of total breadth 38 



38(39) Spore: breadth shorter; sutural diameter 14/x, breadth 17^ 



Ceratomyxa abbreviata Davis 1917 • (76) 



39(38) Spore: breadth longer; sutural diameter 12 to 15/u, breadth 45 to 50/u 



Ceratomyxa reticularis Thelohan 1895 (68) 



40(35) Spore straight 41 



41(42) Sutural diameter 11 /i, breadth 27m. Trophozoite always rounded 



Ceralomyxa amorpha Davis 1917 (78) 



42(41) Sutural diameter 6^ 43 



43(44) Trophozoite with active pseudopodia. Spore: sutural diameter 6n, breadth 



22 to 24m 



Ceratomyxa undulata Davis 1917 (79) 



44(43) Trophozoite with inactive pseudopodia. Spore: sutural diameter 6m, breadth 



31m 



Ceratomyxa inaequalis Doflein 1898 (68) 



45(22) Sutural diameter less than one-fifth of total breadth 46 



46(49) Breadth of spore equal to or greater than 50m 47 



47(48) Shell-valve tapering gradually toward distal end; sutural diameter 8m, breadth 

 50 to 56m. Trophozoite usually elongated pyriform 



Ceratomyxa mesospora Davis 1917 (73) 



48(47) Shell-valve rounded at distal end; sutural diameter 6 to 7m, breadth 50m. Tro- 

 phozoite usually rcmnded or irregular form; size small 



Ceratomyxa aggregata Davis 1917 (79) 



49(46) Breadth of spore smaller than 30m 50 



50(51) Trophozoite ordinarily spherical, diameter not exceeding 16 to 20m; protoplasm 

 extremely pale looking. Spore: sutural diameter 5m, breadth 25 to 30m. 



Ceratomyxa pallida Thelohan 1895 (67) 



51(50) Trophozoite pyriform with a long posterior process; movements by wavelike 

 motion of ectoplasm; also active backward movements of pseudopodia. Spore 

 asymmetrically built; sutural diameter 5m, breadth 24 to 28m 



Ceratomyxa agglomerata Davis 1917 (77) 



52( 1) Spore variable in size and form 53 



53(54) Variation in number of shell-valves conspicuous; sutural diameter 5m, breadth 



25m 



Ceratomyxa truncata Thelohan 1895 (67) 



54(53) Variable in size and form of spore, but not in number of shell- valve 55 



55(60) Trophozoite more or less definite in shape 56 



56(59) Trophozoite usually pyriform 57 



57(58) Trophozoite disporous. Spore: sutural diameter 7 to 9m, breadth 15 to 38m 



Ceratomyxa lunata Davis 1917 (76) 



58(57) Trophozoite monosporous or disporous. Spore: sutural diameter 5 to 6m, 

 breadth 18 to 25m 



Ceratomyxa monospora Davis 1917 (78) 



Numbers enclosed in parentheses refer to the page of the article on which is found the description of the species 

 named. 



