494. E. ELEANOR CAROTHERS 
the result in the case where no confusion was possible, owing to 
both accessory and tetrad appearing in the same section. As a 
net result, then, in the 300 cells drawn, the smaller dyad would 
have gone into the same second spermatocyte as the accessory, 
146 times, or in 48.6 per cent of the cases; and the larger one, 154 
times, or in 51.3 per cent of the cases. I might further state that 
32 cells were drawn from one individual and a larger number from 
another, each giving substantialy the above results, before I saw 
the trend of the evidence. 
Second spermatocyte figures are not striking in my material 
on account of the lesser difference in volume of the dyads, but 
early anaphases of the first spermatocyte, such as figures 33, 34, 
41, 42, 45, 49 and 57 where the attachment of the spindle fibers 
is clearly evident, speak for themselves. The majority of my 
drawings are of early metaphases as represented in figures 30 to 
32, 37 to 40, and so forth, but with a number of later figures to 
substantiate them, there seems to be no reason to doubt their 
reliability. More conclusive still, are polar views of late ana- 
phases (figs. 58, 61 to 64). Figures 61 and 63 contain twelve 
chromosomes, including the accessory; in figure 63 one of the 
three small dyads ig markedly larger than the other two—the 
larger dyad; while in figure 61 one is slightly smaller than the 
other two—the small dyad. Figures 58, 62 and 64 are eleven 
chromosome groups, the first two containing the larger, the last 
the smaller dyad. me: 
One peculiarity is yet to be noted. In many instances the 
larger dyad has a constriction about one-third nearer the proximal 
than the distal end (fig.57) corresponding to the tripartite appear- 
ance of the prophase. Usually it is very slight; sometimes no 
indication of it can be found, while in a few instances it is carried 
to the extreme seen in figure 29. Apparently this is an individ- 
ual variation. | ; 
The unequal pair is comparable to any of the other tetrads and 
is not part of a sex group, such as has been described by Payne 
(09), since the distribution of its parts is not related to sex, as 
indicated by the presence or absence of the accessory. As a 
corollary, it follows that its arrangement on the spindle is a matter 
