220 SOME MINUTE ANIMAL PARASITES 



England, though it occurs. It is more common in 

 N. bombycis in the silkworm. 



The third case is that in which a meront grows 

 very large before any division of its nucleus begins. 

 When such a large meront is actually within one of 

 the epithelial cells of the host, it usually happens 

 that the nucleus of the meront divides into four 

 (Fig. 40, ), and the greater, part of the body cyto- 

 plasm divides into four also. Four daughter meronts, 

 then, are produced within the remains of their parent 

 form. Occasionally, the large meronts show great 

 delay in the separation of their cytoplasm, though 

 the nuclei multiply with rapidity. Ultimately each 

 of these nuclei collects cytoplasm around itself and 

 becomes a spore. These large meronts may lie 

 within cells of the gut epithelium, but more often 

 they are found between the cells. 



The formation of the digestive juices of the bee 

 is peculiar, for the cells containing the digestive 

 fluids are themselves cast off into the gut cavity, and 

 it is not until they disintegrate there that their secre- 

 tion is liberated* Should the cells contain parasites 

 (Fig. 41, B), these are set free at the same time as 

 the digestive fluids, and, consequently, both planonts, 

 large and small meronts, and spores of the Nosema 

 can be found freely floating in the gut contents. 

 Should the cells not be shed, the nests of meronts 

 continue their development, until each infected cell 

 contains a colony of meronts, each of which ulti- 

 mately becomes a shining, oval spore, the colony lying 

 within the space occupied at first by the original 

 meront (Fig. 41, A). 



