MALE AND FEMALE COCCIDIA 127 



rodlike bodies (Figs. 27, < ; 28, K, (), around each 

 of which a minute quantity of cytoplasm collects 

 and is continued outwards as two fine, trailing 

 threads or flagella (Fig. 28, K, ^). A very large 

 amount of the body substance of the male mother 

 cell is not used at all, but remains behind when the 

 male cells (microgametes) break from the parent 

 and swim away in search of the female (Fig. 28, L). 

 Though they are very minute, only about -S-GWG m ch 

 in total length, the males are capable of very rapid 

 motion. They move with a gliding serpentiform 

 action, and when attracted to the female by some 

 chemical substance secreted by it, behave with great 

 vigour. 



Fertilization has been seen in life. Prior to the 

 actual fusion of the sexual forms, the female parasite 

 has thickened its cyst wall, but has left one spot in it 

 much thinner than the rest. Vigorously lashing 

 their flagella, several males approach this weak spot, 

 or micropyle, and attempt to penetrate within. One 

 at length succeeds, and the stimulus of its entry has 

 the effect of producing almost immediate thickening 

 of the micropyle and exclusion of its companions 

 (Fig. 28, L), which after more vain attempts 

 weaken and die in the mucilage usually to be 

 found around the micropyle. The flagella of the 

 male take no further part in the development, but 

 are discarded. The nucleus of the male, however, 

 spirally bores its way inwards until it comes to rest 

 above the nucleus of the female (Fig. 28, Af), when, 

 by a somewhat complicated process, the intimate 

 mixture and fusion of the two nuclei is accomplished 



