190 ILLINOIS BIOLOGICAL MONOGRAPHS [428 



9( 2) Breadth of spore less than half of length 10 



10(17) Breadth of spore more than two-fifths of length 11 



11(16) Spore without any process 12 



12(15) Shell of uniform thickness 13 



13(14) Spore bent to one side; shell thickened at sUghtly rounded anterior tip; sutural 

 edge without marking; length 16 to 18;u, breadth 7 to 8/i, polar capsule 5 

 to 7 m long 



Myxobolus piriformis Thelohan 1892 (J2!f) 



14(13) Spore straight; shell thickened at posterior part; sutural edge with four to six 

 markings; length 18 to 20^, breadth 8^, thickness 6ju, polar capsule 9 to lO/x 

 long 



Myxobolus fuhrmanni Auerbach 1909 (130) 



15(12) Shell of uniform thickness; valves S3anmetrical; sutural edge with markings up to 

 12 in number; spore 14 to 15 . 5m long, 6 to 7 . 3m broad, 5 to 6m thick, polar cap- 

 sule 6.3m by 2 to Sfj, 



Myxobolus misgurni Kudo 1919 (133) 



16(11) Spore with a posterior process, 5m in length and as broad as spore; length 17 to 

 18m, breadth 7.5 to 8m, polar capsule 7m by 4m 



Myxobolus notatus Mavor 1916 (131) 



17(10) Breadth of spore about one-fourth of length; spore large; polar capsule extremely 

 large; length 30 to 32m, breadth 7 to 8m, length of polar capsule 22 to 23m 



Myxobolus rohilae Southwell et Prashad 1918 (132) 



18( 1) Spore with two polar capsules 19 



19(24) Form of spore variable 20 



20(23) Spore with an intercapsular appendLx at anterior end 21 



21(22) Spore oval; length 10 to 12m, breadth 8 to 9m, thickness 6m, polar capsule 5m by 2 

 to 3m 



Myxobolus miilleri Biitschli 1882 (128) 



22(21) Spore pyriform or elongated oval; length 11 to 16m, breadth 8 to 13m, polar cap- 

 sule 6m by 4m 



Myxobolus cycloides Gurley 1893 (140) 



23(20) Spore without intercapsular appendix; circular form 7 to 8m, breadth 8 to 10m, 

 thickness 6m, polar capsule 4 to 5m by 2m 



Myxobolus hylae Johnston et Bancroft 1918 (153) 



24(19) Form of spore definite 25 



25(28) Polar capsules in each spore regularly of considerably different size 26 



26(27) Spore with an intercapsular appendix; anterior end rounded; sutural edge with 

 folds (3 to 5); length 10 to 12m, breadth 8m 



Myxobolus dispar Thelohan 1895 (135) 



27(26) Spore without intercapsular appendix; anterior end pointed; no fold on sutural 

 edge 



Myxobolus inaequalis Gurley 1893 (135) 



28(25) Polar capsules approximately of equal form and size 29 



29(30) Sutural diameter smaller than breadth; length 6 to 7m, breadth 8m 



Myxobolus transovalis Gurley 1893 (139) 



30(29) Length equal to or more than breadth of spore 31 



31(102) Length longer than breadth 32 



32(37) Breadth of spore less than half of length 33 



33(34) Extremities of spore equally pointed; length 13 to 14. 5m, breadth 6 to 7m, polar 

 capsule 4.5m long 



Myxobolus miyairii Kudo 1919 (155) 



34(33) Anterior end of spore attenuated; posterior end rounded 35 



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

 named. 



