524 ROBERT W. HEGNER 
this time the cytoplasm appears to be homogeneous throughout. 
Martin finds in Ageniaspis at this stage a cloud of granules in the 
posterior region (fig. 70) but nothing of the sort is present in my 
preparations, nor were such granules observed by Silvestri 
in Copidosoma bussyoni. Silvestri (714), however, thinks he 
has discovered a group of granules at the posterior end of the 
nucleus at about this stage (fig. 69) which he suggests may lead 
to the formation of the oosoma (formerly called by him the 
‘nucleolo’ and designated by me as a keimbahn or germ-line- 
determinant). 
The nuclear phenomena are of considerable interest from this 
time on. The spireme becomes more and more open (Stages 
D, E, figs. 49, 50) and finally breaks up into thin, chromosomes 
of irregular shape (Stage F, fig. 51). These chromosomes then 
become shorter and thicker and appear to unite near their ends 
(Stage G, fig. 52). At first the pairs are scattered about within 
the nucleus (fig. 58) but they soon straighten out and become 
arranged in a parallel series with their points of union lying in the 
equator (Stage H, figs. 53, 59, 60). Spindle fibers could be seen, 
but apparently no centrosomes or asters are present. ‘The num- 
ber of pairs of chromosomes as indicated by cross sections of 
spindles of this sort seem to be twelve, the same number re- 
corded by Silvestri for C. bussyoni, but several very clear sections 
contain only eleven (fig. 61). 
Soon after the parallel arrangement of the chromosome pairs 
occurs, the egg reaches its full growth and attains its definite 
shape (Stage I, fig. 54). The mitotic figure then passes through 
the stages of condensation, as described in my preliminary report 
(Hegner 714 b). The chromosomes gradually get closer together 
and become shorter and thicker (fig. 62). Where their ends meet 
at the equator a ridge appears, which causes the complex to 
resemble a maltese cross (fig. 63). Soon the spaces between the 
chromosomes are entirely obliterated (fig. 64) and a homogeneous 
mass of chromatin results (fig. 65). 
Silvestri has noted the parallel arrangement of these chromo- 
some rods, but has evidently failed to observe their condensation. 
Martin, however, has reported a similar phenomenon in Agenias- 
