SPERMATOGENESIS IN ASILUS SERICEUS 169 
gate gives rise to a long double thread by a process of attenu- 
ation or uncoiling (fig. 1). This thread shortens up immediately 
into a pair of prophase chromosomes (fig. 2).^ 
FINAL SPERMATOGONIAL TELOPHASES 
Since the telophase of the last spermatogonial* division is a 
stage of particular interest, it may be considered separately. 
In the last spermatogonial anaphase, as in preceding anaphases, 
the chromosomes go to the poles associated in pairs. In late 
anaphase the pairing becomes more intimate, due partly to the 
crowding of the chromosomes at the poles. Then in telophase 
the crowding is relaxed, the cluster loosens up, and the individual 
chromosomes may be observed. They are now intimately 
associated in pau^s — so intimately, indeed, that the duality is 
often obscured. In other words, as the cluster loosens, the 
chromosomes separate out as bivalents instead of single elements. 
In figures 6 and 7 different degrees of association are represented. 
Some of the chromosomes show the dual structure clearly, while 
others show it very little or not at all. These nuclei are entire, 
or nearly so, and all of the chromatin is represented. Figure 
8 is from a slightly later stage in which the paired association 
is so intimate that all trace of duality is gone, and only five 
chromosomes can be detected. 
The staining capacity of the chromatin is greatly decreased 
at this time and the chromosomes appear less bulky than before. 
Needless to say, such figures are difficult to analyze, but a careful 
study has convinced us that the process is as described — that 
homologous members join in early telophase and effect an inti- 
mate union side by side. This conclusion is based not only on 
the duality of the telophase chromosomes, but on the fact that 
they are haploid in number (5) instead of diploid (10). The 
cells are small, affording plenty of examples of uncut nuclei, 
and in no case have we been able to find one in which the chro- 
matic bodies approached the diploid number. Indeed, we found 
no clear case in which more than five were present. 
^ These features, together with other details omitted in the present paper, will 
be considered more fully in a subsequent publication. 
