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Wm. S. Marshall, 



cells; in structure they are similar to tliose we described (Fig. 2) 

 from an earlier stage. Distally within tlie end Chamber are a nnmber 

 of cells witli undifferentiated nuclei (Fig. 42 a) ; tlieir similarity, botli 

 to tliose occupying a like position in younger tubules (Figs. 4, 15 

 and 35 a) and to nuclei of tlie terminal filament, is noticeable. Otlier 

 early stages are found in tliis region, those in which tlie cliromatin 

 granules are very large (Fig. 42 b) and also nuclei in wliicli tlie 

 acliromatin Strands are becoming prominent (Fig. 42 c). Whether all 

 tlie most distally situated nuclei have cell boundaries oi not is dif- 

 ficult to determine. Proximal to tliese cells is a group in whose 

 nuclei tlie spireme-tlireads heve been formed (Fig. 42 d). These do 

 not here show any Variation s, the threads stain but lightly, and they 

 belong therefore to a stage previous to synapsis. Foilowing these 

 are some cells whose nuclei have very distinct paired chromosomes. 

 In all these a chromatin nucleolus is present. The paired chromo- 

 somes lie in small achromatin masses. To the left in this figure 

 are shown a few abnormal cells which are disintegrating , and have 

 already lost their regulär form and structure. Such bodies are found 

 in many of the sections from ovaries of dififerent ages, but not so 

 abundantly in young, as in old ones. 



The next part (Fig. 43) shows a few undifferentiated nuclei, 

 which later become epithelial cells, and three groups of oöcyte and 

 accompaning nurse-cells. The proximal of the three groups shows 

 only four nurse-cells, the oöcyte belonging to these, not being in the 

 section from which the drawing was made. Just distal to these three 

 groups are a number of cells (Fig. 42) in whose nuclei are many 

 paired chromesomes; here in the groups we also find a similar 

 structure in the oöcyte nuclei, but see that in the nurse-cells they 

 have begun to break up. This is here similar to what we described 

 for the last stage. The paired chromosomes always disappear from 

 the nurse-cells earlier tlian from the oöcytes. 



The remaining and much the largest part of the tubule (Fig. 41), 

 is composed of five distinct Chambers which show a regulär gradation 

 in size. The oöcyte of each of the first two Chambers sends a large 

 Munt process up between the nearest nurse-cells (Fig. 44). The 

 nucleus of this, the youngest, oöcyte shows the paired chromosomes 

 still present, and with these a large achromatin nucleolus. In the 

 next oldest oöcyte this is not the case (Fig. 46), the paired chromo- 

 somes have nearly disappeared as such, and in their place an irregulär 

 chromatin rod or small mass is seen. In still the next oldest oöcyte 



