158 MC/sVSOuV. [V^OL. XV. 



Figs. 106, 1 15, 1 17, 1 18). It is one of the most pronounced 

 characteristics of the nucleolus at this stage. In the nucleolus 

 of the living egg the outer crescent-shaped zone appears to be 

 studded with spherical bodies imbedded in it (PI. XVI, Fig. 

 108). Whether these are mere fluid vacuoles or solid bodies, 

 cannot be made out. The central body often appears like a 

 vacuole, but more frequently it is granular. The granules 

 vary in size, not only in the same nucleolus, but in different 

 nucleoli (PI. XVI, Figs. 108, 115, 117). 



In preserved material this central body is seen to be solid 

 or composed of granules, as was the case in the living egg. 

 The central body may at times be greatly enlarged. The 

 outer crescent-shaped body then appears as a cap at one pole 

 of the central body. The horns of the crescent, in sections, 

 becoming greatly thinned out, extend along the sides of the 

 central body. At other times the central body is not so 

 large, the outer zone being larger in proportion. The central 

 body may then be elongated into a cylinder-like body with 

 rounded ends, the outer end projecting through an opening in 

 the outer zone at the point where this is thinnest (PL XVI, 

 Figs. Ill, 113). This reminds me strongly of the observations 

 of Aime Schneider and Balbiani ('83), The inner end of the 

 projecting body may be simply rounded, or it may be somewhat 

 enlarged. The whole body may be spherical in form (Fig. 1 12). 



In these cases the outer zone stains more deeply than the 

 inner body, e.xcept in Heidenhain's iron-haematoxylin, in which 

 the central body takes a dark stain. 



The body can often be seen to have been extruded (PI. XVI, 

 Fig. 1 10; PI. XV, Fig. 79). In such cases a cavity, which 

 communicates with the exterior by means of a circular opening, 

 exists in the nucleolus. The extruded body can be seen in all 

 stages of extrusion. When this has occurred, it is sometimes 

 seen lying close to the opening (PI. XVI, Fig. no; PI. XV, 



Fig. 79)- 



The extruded body assumes a spherical form, and, except in 

 Heidenhain's iron-haematoxylin, loses more and more its power 

 of staining. Finally, it resembles an ordinary yolk sphere of 

 the last stage of the egg. 



