452 Ferguson . — The Development of the Egg and 
beautiful preparation was obtained at this stage in which 
a single section through the nuclear plate showed twenty-four 
entire chromosomes, and no chromosomes were found in the 
other sections of the series (Fig. 62).. As twelve chromosomes 
had previously been counted in the egg-nucleus, there can be 
little doubt that the same number is brought into the egg by 
the sperm-nucleus. 
The smallness of the mitotic figure in the first division 
following fecundation compared with the size of the egg- 
nucleus has been commented upon by all students of the 
Abietineae. This spindle may occupy various positions in 
the space originally filled by the egg-nucleus ; but, as is clearly 
demonstrated by a study of its development, it invariably lies 
partly within the sperm- and partly within the egg-nucleus, 
its major axis being always parallel with the outer free surface 
of the sperm-nucleus. While, then, the division-figure bears 
a certain definite, fixed relation to the conjugating nuclei, it 
will be readily seen that its position may vary, depending 
upon the shape of the sperm-nucleus and its line of contact 
with the egg-nucleus, as, also, upon the plane at which the 
section is cut with regard to the sexual nuclei. For instance, 
when the sperm-nucleus is elliptical in outline, and lies in 
a deep depression in the egg-nucleus, as illustrated in Fig. 48, 
the spindle will appear to occupy the centre of the egg-nucleus. 
Cases like the above and many others were first satisfactorily 
interpreted after a careful study of something like two hundred 
preparations showing fertilization-stages. 
During matakinesis the mitotic figure may present every 
variation between the extremely broad, multipolar diarch, 
shown in Fig. 63, and the narrow, almost bipolar spindle, 
illustrated in Fig. 64. It is at this time that the longitudinal 
splitting of the chromosomes first becomes apparent. Each 
chromatic element divides at the point where the spindle- 
fibres are attached, forming a small diamond-shaped opening. 
While this opening is still inconspicuous, the two halves of 
each chromosome become distinct throughout the entire 
length of the segment. Such a condition was several times 
