400 KING. [Vour. XIX, 
are indistinguishable from the chromosomes at the time that 
the latter are surrounded by a ring of nucleoli shortly before 
the maturation period. While Lubosch finds that the primi- 
tive chromatin network becomes extraordinarily fine at certain 
stages of development, he states that it never completely dis- 
appears and that it is morphologically present in the ripening 
egg, although it is in a finely divided form. 
From the stage of Fig. 39 until that of Fig. 50, when the 
nucleus has reached its maximum size and the nucleoli have 
migrated to the centre preparatory to their final disintegra- 
tion, the nuclei in the ova of Bufo contain an almost endless 
variety of nucleolar figures. In the nucleus shown in Fig. 
39 the nucleolar bodies are of various sizes and they react 
very differently towards the gentian violet and safranin stain. 
The very small rounded nucleoli are karyosomes, since they 
stain like the chromatin; the larger, rounded nucleoli may be 
considered as plasmosomes, since they stain red and are not 
connected in any way with the chromatin; the irregular body 
marked X stains purple, and is a compound-nucleolus which 
has not yet begun its resolution; while the small, slightly ir- 
regular bodies are secondary compound-nucleoli which have 
been evolved from the resolution of a large mass similar to 
that shown in Fig. 35. At Y is shown a nucleolar body which 
is very similar to certain of the resolving nucleoli figured by 
Carnoy and Lebrun. This body is composed of a large, rounded 
central plasmosome (staining uniformly red) which seems 
to be giving off a number of small buds that also take the saf- 
ranin. The outer surface of this plasmosome appears some- 
what irregular and stains purple because a number of oxy- 
chromatin granules are attached to it. This structure has 
been produced, evidently, by the resolution of one of the com- 
pound-nucleoli which contained only a comparatively small 
amount of chromatin. The pinching off of small plasmo- 
somes from a larger mass is a very common phenomenon in 
the ova of Bufo, and it is evidently one of the ways in which 
the number of these bodies is increased. 
Several small nucleoli are shown in Fig. 39 which are com- 
posed of an outer ring of substance, evidently chromatin, since 
