422 KINGS Viol XIX, 
a 
teen days old can this structure be distinguished with any 
degree of certainty. I shall apply the term “vitelline body” 
to this structure and also to other bodies of similar character 
which appear later in the cytoplasm, reserving the term, “yolk- 
nucleus” for the granular masses found in the cytoplasm at a 
much later period of development. 
The vitelline body divides previous to each cell mitosis (Fig. 
7, V). In sections of the ovaries of young toads this struc- 
ttire is found in the primary oogonia (Figs. 16-17), in the sec- 
ondary oogonia (Figs. 18-19), in the young oocytes at the 
critical period when the cell contents stain very faintly and 
cell boundaries and nuclear outlines are made out with diff- 
culty (Fig. 20), and also during synizesis and early post- 
synizesis stages (Figs. 23-31). 
In the early stages of development a cell rarely contains 
more than one vitelline body unless it is preparing to divide. 
During synizesis the vitelline body enlarges somewhat and 
at a slightly later period it becomes oval and then constricts 
through the middle so that it has the appearance of a dumb- 
bell (Fig. 47, a); subsequently it divides into two rounded 
parts (Fig. 47, b), which soon separate (Fig. 47, c). The 
vitelline bodies thus formed divide repeatedly, and by the time 
that the odcyte has reached the stage of Figs. 36-39, its cyto- 
plasm contains a considerable number of these bodies which 
vary greatly in size, although they all appear round and homo- 
geneous. Sometimes at this stage a vitelline body is enclosed 
in a clear area which marks it off from the cytoplasm, but 
this is not a constant phenomenon. Occasionally a vitelline 
body does not divide in the manner described above, but it 
breaks into three small parts (Fig. 38, Y); in other cases 
division is unequal and one large and one small body are 
formed (Fig. 38, X). Since the vitelline bodies vary so 
greatly in size and are so widely scattered throughout the 
cytoplasm at the stage of Fig. 39, it seems very probable that 
some of them are newly formed secretion products of the 
cytoplasm which appear first as minute granules and gradually 
increase in size. 
