126 PROTOPLASM 



of the protoplasm very distinctly as a fine reticulate mesh- 

 work. The sections were further stained on the slide with 

 Delafield's haematoxylin, as a result of which the true proto- 

 plasmic framework was, as usual, only very feebly tinged or 

 not at all. The relatively dark coloration, which the proto- 

 plasm takes on in haematoxylin, depends in the main much 

 more on the numerous fine, strongly staining granules which 

 are lodged in the nodal points of the framework. 



On the surface of the yolk a radiate alveolar layer can 

 be made out plainly (Plate V. Fig. 1, 6), and the eggs which 

 were investigated after the second cleavage also showed the 

 layer of alveoli very plainly on each side of the surfaces of 

 contact of the two segmentation spheres. 



From the investigation of eggs during the process of 

 segmentation it was shown that the radiating appearances 

 of the so-called asters or suns only depended on the arrange- 

 ment of the meshes of the protoplasmic framework. This 

 can be demonstrated even in entire ova killed with picro- 

 sulphuric acid (Plate V. Fig. 1, c), but of course much more 

 clearly and better in sections cut as thin as possible. The 

 similarity is very great between the arrangement of the 

 meshes and that formerly described in the radiating proto- 

 plasm of the central capsule of Thalassicolla. On Plate V. 

 Fig. 1, &, a fine section is figured through one of the suns of 

 the nuclear spindle of a dividing ovum. The section passes 

 a little obliquely with reference to the axis of the nuclear 

 spindle, which makes its appearance in the next section, and 

 shows a distinct equatorial nuclear plate. In the centre of 

 the sun or aster the so-called polar or central body, which 

 is relatively strongly stained, may be noticed. It seems 

 to consist of three vesicles provided with strongly stained 

 walls. This central body lies in the clear, quite unstained 

 central area of the radiations (" sphere of attraction," 

 Beneden ; " archoplasma," Boveri), which in its turn is 

 again enclosed by the rather intensely stained and radiating 

 external protoplasm. The central area also is radiately 

 disposed throughout. The central body is immediately sur- 

 rounded by a zone of small extent composed of an irregular 

 mesh work of protoplasm, which passes directly into the 



