A STATISTICAL STUDY OF MITOSIS AND AMITOSIS. 



225 



and arranged in a reticulate manner, can be seen oozing out into 

 the " body cavity." These large dorsal cells are continuous with 

 the liver cells. 



While it may be inferred, from facts to be presented later that 

 the cells in the posterior part of the digestive tract are engaged 

 in the digestion and storage of food materials, those in the ante- 

 rior end, on the basis of the histological evidence given above, may 

 be assumed to be engaged in a process of internal excretion. 

 This assumption gains in validity when we recall that an immense 

 amount of yolk must be metabolized and also that the oesophagus 

 is at the level of the external kidneys. Though many of the 

 outermost cells show signs of " overwork " the disintegration 

 which this brings about is in no sense pathological, since it 



L 



D 



Fig. 5. A transverse section through the posterior half of a larva in stage VI. 

 Z, lateral ; v, ventral ; d, dorsal ; ventrally and laterally is the comparatively undiffer- 

 entiated entoderm ; dorsally are the large liver cells. 



