John P. Munson 323 



especially in cytoplasmic stains, because of the increasing affinity of its 

 granules for such stains. Hematoxylin and picro-carmine, however, 

 make certain aspects of the reticulum very evident. The finer strands 

 of the network, so beautifully evident in the early stage, are not now 

 visible; but bead-like rows of deeply-staining spheres, somewhat resem- 

 bling the smaller nucleoli, appear as isolated or continuous strands run- 

 ning in wavy lines through the granular matrix (Plate III, Fig. 63; 

 Plate IV, Fig. 68; Plate V, Fig. 75; Plate VI, Fig. 82). From the 

 bead-like bodies of which these chromosomes are composed, there seem 

 to radiate delicate fibrils, giving a woolly appearance to the chromosome 

 bands. This is not visible at all times in the same kind of material. I 

 presume it is due to the finer fibrils of the obscured network. 



The position of the germinal vesicle, as in the preceding stage, is 

 very constant. It is never exactly at the center of the egg. Its eccen- 

 tricity seems to be constant, though I cannot say that it is absolutely so. 

 In sections at right angles to the egg-axig, it is central (Plate III, Figs. 

 57, 58, 59). But in sections parallel with that axis, it is always removed 

 from the center; and, in most if not in all eggs in this and the preced- 

 ing stage, occupies a position about midway between the egg-center 

 (cytocenter) and the periphery. An inspection of the plates will hardly 

 tend to convince one of the truth of this statement; but in many, if not 

 all cases, the exceptions in this respect are due to the fact that the section 

 does not coincide with the egg-axis, or else does not pass through the 

 center of the germinal vesicle. 



The cause of this constant eccentricity of the germinal vesicle is the 

 presence, at the egg-center, of the centrosome and sphere, which in this 

 and in later stages I have called the cytocenter, partly because, although 

 it is a direct continuation of the centrosome of the dividing oogonia, and 

 of the sphere of the earliest stage of the oocyte, it often departs so far 

 from what has generally been understood by the term centrosome and 

 sphere. 



The eccentricitij of the germinal vesicle is such, that the cytocoel (outer 

 limit of cytocenter) intersects it considerably below the middle (Plate I, 

 Figs. 25, 26; Plate II, Figs. 29, 34, 35, 36, 38, 39, 40, 49, 50, 51). 

 Comparing these figures with Plate I, Figs. 12, 14, 16, 17; Plate VII, 

 Figs. 96, 97, 84, it becomes evident how little this relation has changed 

 even in eggs of the considerable size represented in Plate VII, Figs. 84, 

 85, 86. I have said that the germinal vesicle is always eccentric. This 

 it must necessarily be so long as the centrosome, and later the cytocenter, 

 occupy the position they do. The cytocenter is always present in this 

 egg, and its persistence throughout this and later stages of the growing 



