NOWLIN : THE VITELLINE BODY IN SPIDER EGGS. 295 



tives, but frequently to the body itself. Very often when the 

 concentrically striated wall is most distinct no central sphere can 

 be seen, and there is a question in my mind whether it is always 

 present. Merkel's fluid is best for showing the central sphere. 

 Stained with iron-hoematoxylin, it appears as a clear, trans- 

 parent body with a definite outline, embedded in a homogene- 

 ous, densely staining mass, which is surrounded by a still 

 denser ring. In some cases the sphere contains granules which 

 stain much like chromatin. Again, in material fixed in Gil- 

 son may be found definite rod-shaped bodies in the central 

 sphere of the vitelline body. ( PI. XIII, fig. 18.) Sometimes, 

 when fixation has proceeded too far, the granules surrounding the 

 central disk will draw together into more compact layers, thus 

 separating slightly from the sphere and also from one another. 

 There can then be seen a network of fibers throughout the 

 vitelline substance, indicating that the latter simply lies em- 

 bedded in the cytoplasmic reticulum. (PI. XIII, fig. 12.) 

 There is at times a suspicion of radially arranged fibers issuing 

 from the central vesicle, but it is by no means distinct, and is 

 probably no more than the network just described. (Fig. 26, 

 pi. XIV.) 



Later apjjearance of the vitelline body. — The vitelline body lies, 

 first, closely applied to the nucleus, even at times indenting its 

 wall. (Fig. 9, pi. XII.) As the dense zone around it clears up, 

 the body moves out from the nucleus, and for a time gets far- 

 ther and farther away. This is during the period of greatest 

 cytoplasmic growth, and the separation of the two bodies seems 

 to be influenced by it. Its distance from the germinal vesicle 

 varies in different eggs, but usually, during the yolk formation, 

 it lies near the periphery of the cell, separated from the nucleus 

 by the entire radius of the cell. (Fig. 28, pi. XV.) The ap- 

 pearance of the body at this time is often peculiar. The central 

 sphere is not distinguishable, and in many respects the body 

 appears to be disintegrating. Figure 28, plate XV, shows the 

 vitelline body lying near the periphery of the cell ; the outline 

 is definite on all sides but one, and here it fades into the cyto- 

 plasm, as if becoming a part of it. The body is no longer com- 

 posed of concentric layers, but the granules which formerly 

 constituted these seem to have formed into definite small, spher- 

 ical bodies, much resembling the small globules of yolk, or 



2-Bull., No. 10. 



