568 E. H. DUSHAM 



however, of first rubbing a drop of albumen on the sUde and then 

 adding water, three drops of the albumen were added to a watch- 

 glass of distilled water, thoroughly mixed with it, and a layer of 

 this was applied to the vslide with a pipette. Sections were 

 then placed on this and flattened by means of heat. By this 

 method the least amount of albumen necessary remains on the 

 slide, but always enough to hold the sections firmly in place. 



Sections were stained with Heidenhain's iron haematoxylin 

 and Delafield's haematoxylin with eosin as a counterstain. Bet- 

 ter cytological results were obtained with the former, especially 

 after fixation with Fleming's fluid, although good results were 

 also obtained after fixation with Bouin's fluid. However, for 

 general histological work, Delafield's haematoxylin and eosin 

 gave very good preparations. 



Prepared mounts of the entire dorsal and ventral walls, sup- 

 plemented by cross and longitudinal sections of the entire abdo- 

 men, showed that these modified hypodermal cells were present 

 in each segment, not only on the dorsal side of the male, but on 

 the ventral side also, and in the female as well as the male (figs. 

 1, 2, 3, and 4). Except in the intersegmental membranes, they 

 are scattered over each tergite and sternite, being extremely 

 abundant at the fore part of each segment laterad of the median 

 line, especially that part of the segment which is overlapped by 

 the preceding segment. Posterior to this region, i.e., where the 

 tergite or sternite is not covered by the preceding segment, these 

 modified cells are more scattered, occurring here and there among 

 the normal hypodermal cells. 



Longitudinal sections show that in the intersegmental mem- 

 branes there is but a single layer of unmodified hypodermal cells 

 (fig. 8, i, and fig. 9, d). The nuclei of these cells are somewhat 

 elongate and flattened, with their long axes parallel to the surface 

 of the overlying cuticula; they are surrounded by but a small 

 amount of cytoplasm, so slight in cases that it appears thread- 

 like with the nuclei bulging out here and there. The nuclei 

 themselves are very deeply stained and are fairly regularly 

 arranged. 



