226 SOME MINUTE ANIMAL PARASITES 



however, on the way to becoming as plastic as 

 N. bombycis, for the planonts have acquired the 

 power of passing through the walls of the alimentary 

 canal and reaching the space that surrounds the 

 viscera, which is the body cavity or haemocoel. The 

 latter name is given because the cavity contains 

 a thin and practically colourless fluid, which is the 

 blood of the bee. When the planonts reach the 

 haemocoel they can divide and form meronts there, 

 and the latter can become spores. But though the 

 parasites are carried by the blood into many organs 

 of the body, they do not seem to have much power 

 of developing in these organs, and so are unlike 

 N. bombycis, which develops equally well in any 

 organ of the body. 



The distribution of N. apis is thus of interest. 

 The oesophagus (Fig. 42, ce.) and honey stomach, 

 or crop (Fig. 42, c.), rarely contain more than the 

 freshly absorbed spores of the parasite, though 

 occasionally amoeboid planonts have been seen creep- 

 ing over the lining of the crop. Beyond the crop 

 is a small lock or stopper (Fig. 42, s.) that com- 

 municates with the more muscular chyle stomach 

 (Fig. 42, c.s.). The walls of this organ are more 

 easily attacked, and the parasites readily penetrate its 

 cells. But the distribution of the parasites is very 

 varied one part of the organ may be swarming with 

 parasites, while an adjacent area is practically un- 

 infected. The same conditions occur in the small 

 intestine (Fig. 42, s.*.), but self-infection occurs here, 

 for some of the spores formed in the chyle stomach 

 liberate their amcebulae in the intestine. The 



