SPERMATOGENESIS OF EUSCHISTUS 779 
greater diameter than in any other preparation, probably because 
they were less strongly destained.'® 
Fig. 86 represents a late prophase of the first maturation divi- 
sion, showing the greater number of mitochondria present, and a 
number of these lie close to the outer surface of the nuclear mem- 
brane (not within the nuclear cavity as the figure might indicate). 
In this and the next following stage (fig. 87) they show no such 
radial grouping around the centrioles as was to be seen in earlier 
stages (figs. 71 and 85). In fig. 88 the first maturation spindle 
is established, and now as in all later stages the mitochondria 
lie outside of the mantle fibers; their peripheral disposition is 
better seen in the polar view represented in fig. 91, where only 
those parts of them are drawn that le in the equatorial plane. 
Figs. 89, 92-94, show other cells of the same stage and demon- 
strate how manifold the arrangement of the mitochondria may 
be and how they do not appear to be influenced in any way by 
the spindle or the centrioles. 
It would seem possible to count them in the stages of the first 
maturation, for at this time they are unusually distinct and large. 
But this is a matter of great difficulty on account of their great 
length and irregular twisting; thus on several occasions I have 
spent several days drawing those of a single cell. Further these 
cells are generally too large to lie wholly within the plane of a 
section, therefore it is not always possible to determine whether 
apparent ends of mitochondria may not be truncations by the 
16 The sections of testis no. 265 showed the mitochondria deeply stained only in 
follicles 1 and 6, those on the periphery which are most affected by the fixative 
(Flemming’s fluid) while in the intermediate follicles the mitochondria were only 
slightly stained, also in thicker sections they are better stained than in thinner 
ones. This illustrates how much a matter of accident it is to secure suitably 
stained preparations. Sometimes it happens that of two cells lying within the 
same cyst, one exhibits the mitochondria very distinctly while the other does 
not. Or again, certain of the mitochondria within a cell stain deeply and others 
faintly, or one mitochondrial thread may be distinct in one portion and pale in 
another, evidently dependent upon depth beneath the surface of the section. I 
have endeavored to select for drawing only those cells in which the majority of the 
mitochondria appeared deeply and uniformly stained, which has required the close 
comparison of a very large number of cells. 
