DAVIS: SPERMATOGENESIS. 105 
same rule holds here. Figures 88, 89 are drawn from two sections 
of the same cell during the metaphase of the first division, all the chro- 
mosomes being shown, while Figures 90, 91 are two successive sections 
of another cell in the same stage and likewise show all the chromosomes. 
In both cells the spindle fibers are evidently attached at the middle of 
the arms of one of the larger autosomes, while in the case of the remain- 
ing two large autosomes the attachment is nearer one end than the 
other. 
In the first maturation division, as we should expect, there are, in 
addition to the three larger autosomes, five smaller autosomes in the 
equatorial plate, which show approximately the same size relations 
as the autosome pairs of the spermatogonia (Fig. NN, p. 96). 
As a consequence of the manner of attachment of the spindle fibers 
described above, the first division must result in the separation of the 
arms of the loop-shaped, bivalent autosomes. Although apparently 
longitudinal in the case of the three larger autosomes, it is nevertheless 
a true reducing division, since, as we have seen, each arm represents 
a univalent autosome. As the univalent components separate they 
assume the usual V-shape, but in the case of the three larger autosomes 
the space between the arms of the Vs does not represent the longi- 
tudinal split as in the smaller autosomes. As the V-shaped univalent 
components of the larger autosomes separate (Fig. 93) each is clearly 
double owing to the reappearance of the longitudinal split. Occa- 
sionally one of the large autosomes may become so placed on the 
spindle that the arms instead of lying on the spindle throughout their 
entire length as usual, project away at an angle (Plate 7, Fig. 187). 
In such cases it is the free ends of the arms which separate first, giving 
rise to characteristic E-shaped forms (Fig. 188; Plate 6, Fig. 91). 
Figure 94 shows the end of the anaphase of the first division. As in 
the preceding species, there is in the secondary spermatocytes a partial 
resting stage (Fig. 95), which lasts but a short time. 
As the chromosomes become drawn into the equatorial plate of the 
second division figure (Fig. 96) the three larger autosomes form double 
Vs and, as in the first division, the attachment of the spindle fibers is 
near the middle of the V-shaped elements. Figures T and U show 
that, as in the first division, in two of the large autosomes the spindle 
fibers are attached nearer one end than the other, while in the third 
large autosome this attachment is at a point directly in the center. 
Thus we have in each of these autosomes a characteristic method of 
attachment to the spindle fibers, which persists through the spermato- 
gonial and maturation divisions. During the second division the 
