PLASMA-STRUCTURE IN EGG OF HYDRACTINIA 205 



egg from the beginning, they are certainly not of direct nuclear 

 origin. Again I find no evidence for their origin from the pseudo- 

 chromatin-granules; for, when the mitochondria first come into 

 view, they are larger than the granules and also stain entirely 

 differently if the Benda method be used. Also they can hardly 

 originate from certain of the yolk-spheres which are of similar 

 size, since again the staining reaction is different and yolk-spheres 

 much larger than the mitochondria are yellow in this stain. These 

 facts all point to their formation de novo in the protoplasm. 



d. Oil globules. These appear very early while the egg is still 

 in the entoderm of the stalk; that is, before the yolk formation 

 has begun and even before all the pseudochromatin-granules are 

 formed (figs. 7, 8, 9, 10). They lie scattered amoung the granules, 

 the number varying much in different individuals. They are in 

 some cases few in number, but in others are frequently very 

 numerous even in this early stage (fig. 8). At this time they are 

 easily confused with the globules which appear against the 

 nuclear wall, since they usually take the same stain. That they 

 are distinct from the nuclear globules is apparent by their greater 

 blackening in osmic acid. Also, in double staining with saffranin 

 and methyl-violet the oil is violet while the globules are red. 

 Again, after Benda's stain, the oil is brownish and the globules 

 violet. Auerbach's stain distinguishes the oil from the pseudo- 

 chromatin-granules, for the latter are green while the former are 

 red. In later stages the oil globules increase greatly in number 

 until the egg is profusely dotted with them (figs. 13, 14). The 

 oil is also formed de novo throughout the growth-period in the 

 protoplasm of the egg. 



Since none of the elements of the mature egg correspond to the 

 large globular masses which appear against the nuclear wall in the 

 early growth-period, it is possible that they form a source of elab- 

 orated food which is used during the process of growth. 



JOURNAL OP MORPHOLOGT, VOL. 25, NO. 2 



