Contr. towards the Embryology and Anatomy of Polistes pallipes- 189 



in BombicSy that in the distal part of the endchamber the nuclei 

 were similar in structure, but larger, than those in the terminal fila- 

 ment. Even before entering this part (Fig. 18 od) we may, here and 

 there, find cells which are changing, and these may lie either in the 

 Center of the tubule (Fig. 19, point 20), or along its margin (Fig. 19, 

 point 22). These cells have changed from the long narrow form to 

 a rounder one but, still greater than this, is the change in the struc- 

 ture of their nuclei. Throughout the distal portion of the tubule the 

 nuclei are all alike and in this region, those which are similar in 

 structure, greatly predominate (Fig. 21). The nuclei of the other 

 cells (Figs. 20 and 22) show a slight increase in size, and a marked 

 difference in their shape. Their structure is also different, the chro- 

 matin granules are a little smaller, the achromatin reticulum more 

 scattered and made up of finer fibrils not so distinct as in the other 

 nuclei. In them there is also seen a fairly large chromatin body 

 which we here notice for the first time, but of which we shall speak 

 again. In this place, and also further down in the tubule, the cells 

 contain a darkly staining bpdy which, for want of a better name, 

 we shall call a yolk-nucleus. It is sometimes an irregulär body but, 

 at this stage, more often has the form of a partially coiled, thick 

 rod; it is always found lying within a clear Space. In all sections 

 this body was noticeable, but especially so in those stained with 

 safranin. 



In this part of the tubule (Fig. 19) there is an irregulär trans- 

 verse striation which stops before the middle part is reached (Paulcke). 

 These Striae are due to Strands of cytoplasm, which are more darkened 

 than the rest; they begin at the wall and extend towards the middle 

 of the tubule some being short and others reaching nearly across. 

 These Striae almost entirely obliterate the cell boundaries which, 

 distal to this region, were very distinct. 



As we pass towards the proximal part of this distal portion of 

 the tubule (Fig. 19), we find that the nuclei lyiug along the margin, 

 become less and less epithelial like in their arrangement, and finally, 

 below the transverse Striae, all trace of it entirely disappears. At 

 this point the larger, rounded cells are more abundant, but as yet 

 their nuclei show no change in structure (Fig. 23). A little further 

 down a change does take place; we find (Fig. 18, point 24) many 

 nuclei showing larger chromatin granules and that the achromatin 

 mass has increased, its Strands being thicker, and widening to form 

 a small irregulär mass around each chromatin granule (Fig. 24). One 



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