580 



PROTOZOOLOGY 



2 3 4 



Fig. 249. Diagram illustrating the development of Eimeria tenella in 

 the caecal glands of chick (Tyzzer). The numbers below indicate the days 

 of infection, ma, macrogamete; me, merozoite (me 1 , me 2 , me 3 , generation 

 1, 2, 3 merozoites respectively); mi, microgametocyte; oo, oocyst; ret. oo 

 and ret. sch, oocysts and schizonts which failed to escape; sch 1 , sch 2 , 

 schizonts of generation 1 and 2; tr, young growing trophozoites. (Continue 

 to upper left of Fig. 250.) 



E. monads Fish (Fig. 248, j). In the intestine of the woodchuck, 

 Marmota monax; spherical to subspherical oocysts 20/a by 18ju (Fish, 

 1930), 14-20/i in diameter (Crouch and Becker, 1931) ; wall compara- 

 tively thick; sporulation completed in 60-64 hours in 2 per cent po- 

 tassium bichromate at room temperature. Crouch and Becker found 

 two other species: E. perf oroides and E. os, in the woodchuck in 

 Iowa. Eimeria in lemming (Levine, 1952). 



E. tenella (Railliet and Lucet) (Figs. 248, k; 249; 250). In the caeca, 

 colon and lower small intestine of chicken; a cause of acute coccidio- 

 sis characterized by haemorrhage (Tyzzer) ; in the caecal contents of 

 California quail (Henry); oocysts 19.5-26/x by 16.5-23^; sporula- 

 tion in 48 hours. Tyzzer's observation on experimental infection in 



