No. 2.] THE OOGENESIS OF BUFO LENTIGINOSUS. 405 
nucleolini when they state that chromatin filaments are often 
found in the interior of large nucleoli. As the result of an 
investigation of the structure of the nucleoli in many kinds of 
cells Montgomery (70) states: “I am forced to conclude tft 
in all probability there are no skeins of chromatin lying in 
any metazoan nucleolus, since I have never found any evidence 
of chromatin in it in any metazoan cell.” This statement may 
well be extended to include the nucleoli in the ege of Bufo, 
since in no case have I ever found chromatin filaments in the 
interior of rounded nucleoli, although they are often found 
wrapped around the exterior of a nucleolus (Figs. 38, 40, 43). 
In preparations stained with safranin and gentian violet 
nucleolar bodies are sometimes found which are similar to the 
compound-nucleoli described above in size and general outline, 
although they have a very different structure as they are com- 
posed of a-number of rounded plasmosomes imbedded in a 
mass of chromatin granules (Fig. 51, a). These bodies are 
compound-uncleoli containing a large amount of chromatin, 
which for some unknown reason did not undergo a resolution 
at the stage of Figs. 35-38. 
Nuclei having a diameter of 0.04-0.08 mm. usually appear 
as in Figs. 39-43. They contain one or two large unresolved 
compound-nucleoli, a varying number of round plasmosomes 
and small karyosomes, together with numerous small com- 
pound-nucleoli which were set free from the large nucleolar 
masses at the stage of Figs. 35-38. These small compound- 
nucleoli, which I shall call secondary compound-nucleoli to 
distinguish them from the larger bodies, appear homogeneous 
and only slightly irregular at the stage of Figs. 39-43, and the 
greater number of them are masses at the side of the nucleus 
where the largest of the primary compound-nucleoli under- 
went a resolution at the stage of Figs. 35-36. In a slightly 
older egg metabolic processes occur which lead ultimately to 
the formation of yolk. These processes are accompanied by, 
if indeed they do not produce, a marked change in the ap- 
pearance and in the behavior of the nucleolar bodies. At 
this stage of development (Fig. 44) there is a mass of very 
