426 KING. [Vor. XIX. 
When the toad has reached a body length of about 4 cm. 
and the egg has a diameter of from 0.18-0.2 mm., there ap- 
pears simultaneously in different parts of the cytoplasm a 
number of irregular, granular masses which I shall call yolk- 
nuclei since they are similar in appearance to the structures 
described under this name by Foot (32), Henneguy, Jordan, 
Calkins (14), and Munson (72). These yolk-nuclei arise as 
rather small, irregular patches of granular substance that are 
not sharply marked off from the surrounding cytoplasm. 
There is at first no regular arrangement of these bodies; some 
lie near the nucleus; others are found near the periphery of 
the egg, while the majority lie in a zone midway between the 
nuclear membrane and the outer boundary of the egg. When 
sections are stained with any of the various combination stains 
previously mentioned, these yolk-nuclei take the plasma stain 
more deeply than does the cytoplasm and hence are easily 
seen. It seems strange that such a keen observer as Goette 
failed to find these bodies in the egg of Bombinator. 
The manner in which these yolk-nuclei are formed is shown 
in Fig. 46. Around one of the larger vitelline bodies there 
appears a clear area, as if the vitelline body had in some way 
caused a liquefaction of the surrounding cytoplasm (Fig. 46, 
X). The substance of this area then becomes changed into an 
irregular mass of minute granules which at first stain but 
slightly darker than the cytoplasm. In some cases the vitel- 
line body can be found in the centre of the yolk-nucleus (Fig. 
46, Y), but as a rule it quickly loses its capacity for staining 
and then disappears, evidently being used up in the formation 
of the yolk-nucleus. As shown in Fig. 53, a yolk-nucleus 
sometimes contains several vitelline bodies of various sizes 
which stain as intensely as at the stages of Figs. 36-39. In 
cases of this kind it is impossible to determine whether the 
vitelline bodies in each yolk-nucleus are produced by the re- 
peated division of the one vitelline body concerned in the 
formation of the yolk nucleus, or whether several vitelline 
bodies originally took part in the formation of a single yvolk- 
nucleus. I am inclined to the former view since the vitelline 
