435 
Embryo of Cryptomeria Japonic a. 
which is characteristic of nuclei preparing for division. It assumes the form 
of definite chromosomes. The stages in the formation of the first segmen- 
tation-spindle were not observed,, but the mature spindle was frequently- 
met with. Arnoldi (’01) reports that the first division takes place at the 
base of the archegonium, Coker (’ 03 ) reports the same condition for 
Taxodium. I was unable to confirm the observations of these writers, for 
every case examined showed the first segmentation-spindle in the middle of 
the archegonium just about the place where the fusion of the sex-nuclei 
occurred. 
The dense zone of starch-granules which surround the fusion-nucleus 
persists until the completion of the first division. Fig. 46 shows the first 
segmentation-spindle completely surrounded by the zone of starch-granules. 
This gives the impression that the spindle is organized within the nuclear 
membrane, but a very close examination failed to reveal a trace of the 
latter. The first spindle is a little larger than those formed in the pro- 
embryo and embryo. It is very sharply pointed at the poles and broad at 
the equator, as shown in Fig. 46. Only a few of the chromosomes are 
shown in this figure ; the majority of them were found in the sections 
immediately following the one from which the figure was drawn. 
The chromosomes of the pro-embryo are very long, V-shaped struc- 
tures. They are always attached to the spindle-fibrils at the point where 
the arms of the V meet. They are just about one-fourth the length of the 
spindle, for when they are situated at the equator, they extend half-way to 
the pole. Fig. 47 shows a spindle of the second division of the pro-embryo 
with the chromosomes approaching the poles. On account of the presence 
of the two long arms which overlapped each other more or less, it was 
practically impossible to accurately estimate the number of the chromo- 
somes. There are approximately eighteen or twenty in the embryo. 
Comparing the typical embryo-spindle as shown in Fig. 47 with a typical 
spindle from the female prothallium as shown in Fig. 48, the difference in 
the number of the chromosomes in the two is very obvious. Hundreds of 
spindles in all stages in both the gametophyte and sporophyte were examined, 
and this difference was always very marked. The gametophyte-spindle 
had not only fewer chromosomes, but it was only about half as wide at the 
equator as the sporophyte-spindle. This is well illustrated in Figs. 47 and 
48. Both these figures were drawn by the aid of the camera lucida and at 
the same magnification. As near as could be estimated there are nine or 
ten chromosomes in the gametophyte, and eighteen or twenty in the 
sporophyte of Cryptomeria . 
The result of the first segmentation is shown in Fig. 50 ; two free 
nuclei are formed and they move towards the base of the archegonium. 
As they move downward both nuclei divide and we have four free nuclei, 
as shown in Fig. 51. So many preparations showed this condition that 
H h 
