22 



THE EMBRYOLOGY OF THE HONEY BEE 



Fig. 9. Tangential section through cone of cleavage cells, Stage II-III, 

 showing arrangement of cells and their relation to one another, x 534. 



points ppposite the centrosomes, when the astral rays may fre- 

 quently be seen attached to the chromosomes and traversing the 

 nucleus. These fibres are plainly evident in preparations fixed 

 in Petrunkewitsch's fluid, but less so in those fixed in picro- 

 formol, as were those from which the series of drawings were 

 made. In figure 8B an attraction-sphere surrounds each centro- 

 some. Figures 8C and D show the metaphases of division. One 

 of the centrosomes is seen to have divided, and this division be- 

 comes even more evident in the anaphases and telophases (Figs. 

 8E and F). Nachtsheim describes a division of the centrosomes 

 at both poles, which would naturally be expected, but the numer- 

 ous preparations studied by the writer for some reason showed 

 a division at only one pole. During the anaphases (Fig. 8E) the 

 centrosomes increase in size and the nuclei frequently have a bi- 

 lobed appearance. This division of the nuclei into two lobes is 

 not uncommon in the early stages of development of other ani- 

 mal forms, as for example Cyclops (Riickert 1895) and Crepi- 

 dula (Conklin 1897). O ne °f the two lobes in such cases is 

 supposed to represent the maternal half of the nucleus, the other 



