PLASMA-STRUCTURE IN EGG OF HYDRACTINIA 201 



nuclear chromatin,' it is important to determine their nature. 

 They are differentiated from other cell elements diagrammatically 

 in figures 4, 5, 7, 8 and 10 by the use of circles containing parallel 

 lines. Although they are so closely applied to the nuclear mem- 

 brane, again I find no evidence of a direct nuclear origin. Their 

 distinction from both pseudochromatin-granules and chromatin is 

 apparent for several reasons. (1) These globules darken in 

 osmic acid while the chromatin and granules as seen in unstained 

 preparations, do not. (2) After Benda's stain, they take a 

 deep violet color, while the chromatin and granules stain yellow. 

 (3) Also in material stained with saffranin and methyl-violet 

 the pseudochromatin-granules are violet, while the globules stain 

 a brilhant red. It is evident therefore that the globules are 

 identical, neither with the nuclear chromatin, nor with the pseu- 

 dochromatin-granules. Since I find, as shown in the figures, no 

 grouping of the granules around the globules, they can hardly 

 be dispersion-centers. The time when globules first appear in 

 the egg is variable, for they may be present as soon as the pseu- 

 dochromatin-granules appear, or not until later. They are found 

 up to the time the yolk begins to appear, sometimes lying a short 

 distance from the nucleus, but never far away (figs. 7-10) . 



To sum up: There are in the early growth-period two proto- 

 plasmic elements, one a fine granular precipitate (pseudochroma- 

 tin-granules) which is scattered throughout the protoplasm and 

 takes basic stains, the other, large drop-like masses which appear 

 near the nuclear wall and which are also probably not chromatin. 

 Neither of these elements appear as such in the mature egg, both 

 being completely used during development. 



During this period the egg is migrating from its original position 

 in the entoderm of the stalk toward the gonophore, where it 

 becomes established in the ectoderm. The increase in the size 

 of the egg is considerable during this process, but still further 

 growth takes place after the egg has reached the gonophore before 

 any change in the condition described occurs, or any evidence of 

 the structures characteristic of the adult egg appear. 



