No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 395 
the nucleus at this time greatly exceeds that found at any 
previous stage in the development of the oocyte, and it 1s evi- 
dent that a new formation of these bodies must take place dur- 
ing or soon after the synizesis stage. The compound-nucleoli 
in a nucleus do not resolve simultaneously. The larger masses 
are always the first to break up, and one or two of the smaller 
bodies may remain unchanged until the nucleus is twice the 
size of that shown in Fig. 36. Soon after the stage of Fig. 
36 the meshwork of fibres becomes very loose and frequently 
breaks into several parts, while the nucleolar bodies begin to 
leave the fibres and scatter about the nucleus (Fig. 38). At 
the stage of Fig. 39 the resolution of the largest compound- 
nucleolus has been completed and the nucleus contains a num- 
ber of nucleolar bodies of various sizes as well as several 
masses of tangled oxychromatin threads which are entirely 
separated from the nucleoli and easily distinguished from the 
chromosomes. 
_ Inhis Fig. 15, Bataillon shows a portion of the nuclear con- 
tents of an ovarian egg of Rana which is very similar to one 
of the larger resolving masses shown in my Fig. 38. Bataillon 
believes that his figure shows the beginning of a connection 
between the chromatin filaments and the nucleoli, and he states 
that later the filaments disappear entirely, all of their substance 
going into the uncleoli. These results dg not accord with what 
I have found in Bufo, since in the oocytes of this amphibian 
the nucleolar bodies are preparing to leave the chromatin 
meshwork at the stage of Fig. 38, and chromatin filaments are 
to be found in all of the later growth stages of the ova. 
At the stage of Figs. 33-34, the chromosomes stain some- 
what more faintly than at an earlier period, and they are com- 
posed of a series of minute granules from which numerous 
fine fibres extend out a short distance on either side. In later 
stages these side projections become much more numerous 
and somewhat longer, and the chromosomes then come to have 
the feathery appearance shown in Fig. 39. At a later period 
the chromosomes stain so very faintly that in many cases they 
are to be found only with the aid of an immersion lens, yet 
