566 L. DONCASTER. 
8. MatTuRATION AND HArRLY DEVELOPMENT OF THE Hae IN 
N. RIBESII. 
A number of eggs of N. ribesii were preserved very shortly 
after they were laid, but in most cases the nucleus had already 
begun to divide, so that the earliest stage commonly found 
was the first maturation spindle. In a few eggs preserved 
about five minutes after laying, the egg nucleus was found 
just beginning to divide, and at this stage it bears a remark- 
able resemblance to the figures given by Henking of the 
corresponding stage in Rhodites (Pl. 35, fig. 2, cf. Henking, 
6, Pl. 7, fig. 203). The mitotic spindle always lies in a little 
mass of protoplasm embedded in the yolk near the anterior 
end of the egg and on the dorsal side, i.e. the side of the 
ego away from the leaf. The “polar protoplasm,” as I 
propose to call this mass, stains differently from the surround- 
ing yolk, and when once its appearance is known it greatly 
facilitates finding the egg nucleus, or at a later stage the 
polar nuclei. There is also a somewhat similar mass 
protoplasm just below the surface at the anterior end of the 
egg, from which in some cases e of protoplasm and more 
finely granular yolk can be traced backward, and I find that 
this is the point where the spermatozoon enters when the 
ego is fertilised. 
The first maturation mitosis begins almost immediately 
after the laying of the egg, and forms a large spindle lying 
perpendicular to the egg-wall. In the anaphase it is seen 
that the spindle fibres are thickened in the middle (Pl. 35, 
fig. 1); this is shown in the figures of Petrunkewitsch (9, 
Pl. 43, figs. 5, 6), and described in detail by Gross in 
Syromastes (3, p. 468), where he ascribes the thickening to 
chromatin left behind on the fibre. The mitosis is never 
quite completed, for as soon as the chromosomes arrive at the 
poles of the spindle, at each end a new spindle begins to be 
formed, and the first maturation division passes into the 
second (fig. 3). In neither of the maturation divisions have 
