650 PROTOZOOLOGY 



marked with 1 longitudinal and 7-9 transverse ridges (Cordero, 

 1919; Kudo and Sprague, 1940). 



M. serotinum Kudo and Sprague (Figs. 282, f-h; 283). In the gall 

 bladder of Bufo terrestris, Rana pipiens, R. clamitans and R. spheno- 

 cephala; in the United States. Trophozoites up to 6.5 by 1.8 mm., 

 extremely thin; cytoplasm highly alveolated; endogenous budding; 

 disporoblastic; polysporous. Spores 16-18ju by 9m; shell-valve with 

 2-4 longitudinal and 10-13 transverse ridges (Kudo, 1943). 







Fig. 283. Scattered spores, young and sporulating trophozoites of Myxid- 

 ium serotinum, as seen in the bile of a frog in life, X64 (Kudo). 



M. kudoi Meglitsch. In gall-bladder of Ictalurus furcatus; troph- 

 ozoites large disc-like up to 1 mm. in diameter; spores 8.5-12/; long 

 by 4-6 m (Meglitsch, 1937). 



Genus Sphaeromyxa Thelohan. Spore fusiform, but ends usually 

 truncate; polar filament short, thick; trophozoites large, discoid; 

 coelozoic in marine fish. Several species. 



S. balbianii T. (Figs. 70, e; 284, g-4). In gall-bladder of Motella 

 and other marine fish in Europe and of Siphostoma in the United 

 States; spores 15-20/* by 5-6 n (Naville, 1930). 



S. sabrazesi Laveran and Mesnil (Figs. 276; 277; 284, j-Z). In gall- 



