222 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Cell Nest 8. The work upon this nest was done with 

 greater care than that upon the previous nests. I first made a 

 camera lucida sketch of the nest in outline, then went over the 

 nest carefully with the high power 8x compensating ocular 

 and marked each division I found upon the outlined sketch. I 

 then used an 8x Huyghenian ocular, upon the diaphragm of 

 which I had placed a micromillimeter scale, and went over the 

 field again, carefully counting the cells by the aid of the mi- 

 crometer scale, and verified the previous locations of the divid- 

 ing cells and located any new ones that I may have missed in 

 the first survey. I thus corroborated my work and made it 

 doubly sure by locating each dividing cell upon an outline 

 sketch. I also used these sketches in the hope that together 

 with the tables I might farther establish the apparent relation 

 of directly dividing cells to the degenerating areas. Where 

 this relation has been especially noticeable I have made high- 

 power camera lucida drawings of the particular field to show 

 some detail about the cells I counted, simply drawing the more 

 important structures in relation to them. Using these large 

 drawings and marking their position upon the smaller sketches 

 one cannot avoid showing in the same way the slide does the real 

 relation of the various dividing cells to these necrotic areas. 

 In these outline sketches I only outlined the nest, tracing into 

 any irregularities among the cells along the edge, so that, un- 

 less otherwise marked, rifts in the nests will mean spaces left 

 where the cells have apparently been pulled apart by external 

 means. The areas that are entirely necrotic will not be dis- 

 tinguished from those that show definite degenerating changes ; 

 cells that are in the "chromatic cell" stage I have counted as ne- 

 crotic. These areas are shown by cross-hatched work. The in- 

 direct divisions are shown by a dot or "X" while the direct 

 divisions are shown by a circle. Starting with figure 10 the 

 sections are in serial arrangement. This cell nest 8 is only a 

 portion of the entire alveolus, showing at the right side of the 

 sketch just the end of a necrotic plug, and leaving the greater 

 part shown in the vigorous condition. I used this nest to con- 

 trast, if possible, the two divisions in these two areas. 



