WENRICH: SPERMATOGENESIS OF PHRYNOTETTIX MAGNUS. 85 
would enable one to trace them, as was done in the case of chromo- 
some-pair A. It is a matter of no small importance, I believe, that 
each of the “selected” chromosome-pairs has been recognizable by 
means of one or both its members, in the spermatogonia as well as in 
the spermatocytes. 
On the other hand, when I came to search through the postspireme 
stages of the other individuals for tetrad C, I was able to find the 
condition shown in figure 65 in only two instances; but a careful study 
of these stages in the remaining animals of the series revealed, in 
place of the large unequal type shown in figure 65, two other types, 
which are shown in figure 107, c-m. Figure 106 presents an example of 
tetrad B from each of the thirteen animals from which material was 
available for study, and figure 107 a similar series of tetrad C. The 
corresponding letters, a, b, c, etc., in the two series represent the same 
animal. We may therefore, speak of the different animals as a, 3, c, 
ete. Chromosome-pairs B and C are the smallest in the whole com- 
plex and it will be seen from these two series of drawings that, except 
in a and b, the pair C is the smaller of thetwo. Inaand }, Cis slightly 
larger than B, as was determined by numerous comparisons in the 
metaphases of the first spermatocytes. The difference in quantity of 
chromatin in these two cases is quite small, however, and differences 
in shape and behavior were largely depended on for identification. 
For convenience in description, we may designate the three types 
of chromosome-pair C as C\, Co, and C3. By Ci will be indicated 
the type, previously described, which is represented in figure 65, and 
at a and 6 in figure 107. The type shown in figure 107, c—h, may be 
designated C2, and that shown in figure 107 at im, as C3. Thus it 
will be seen that (with a possible exception yet to be discussed) of the 
thirteen animals studied, two exhibited the type C1, six the type C2, 
and the remainder, five, the type C3. 
If now we compare types Ci and (C2, it will be apparent at once that 
both members of the pair Cz resemble the smaller member of (Ci. 
The homology is striking if one notices the polar granules and the pair 
of granules close to them, both of which gppear in about the same 
_ relative size and position in all the examples of both types (except h). 
It is therefore not difficult to believe that type C2 does actually repre- 
sent a pair of chromosomes homologous to the smaller conjugant in 
type C1. 
Turning to type C3, as shown in figure 107, 7—m, it will be observed 
that this is quite different from either C, or Cy. It represents an 
unequal pair but the larger member is very different from the larger 
