Embryo of Cryptomeria Japomca. 431 
tion. Fig. 37 represents a typical mature archegonium ready for fer- 
tilization. The egg-nucleus is at this time always centrally situated, and 
below this is a large vacuole. With the exception of the character of the 
neck-cells the mature archegonium of Cryptomeria is strikingly like that of 
Thuja (Land, ’ 01 ) and Taxodium (’ 03 ), and, as we shall see below, the 
grouping of the archegonia is distinctly of the Cupresseae type. 
In regard to the distribution of the archegonia, my observations agree 
very closely with those of Arnoldi (’ 01 ). They are grouped in exactly 
the same way as in the Cupresseae. The number varies from eight to 
fifteen, and they nearly always form a single compact group at the apex of 
the prothallium as shown in Fig. 39. The necks of the archegonia are not 
on a level with the tip of the prothallium, but open into a very distinct 
depression, as indicated in Fig. 39. In longitudinal sections only four or five 
of the archegonia may be seen, but cross-sections show the entire number 
and also the way they are arranged. Fig. 40 represents a cross-section of 
the prothallium in the region of the nuclei of the archegonia. 
As reported by Arnoldi (’ 01 ), there is a common jacket surrounding 
the group of archegonia. The jacket-cells extend nearly as far as the 
neck, and for a considerable distance constitute but a single layer. 
Towards the base there may be two or three layers of jacket-cells, but 
at the base and below the archegonia there are several layers of them. 
Not infrequently the jacket-cells were found extending a little way up 
between the archegonia, and occasionally, as shown in Fig. 39, they extended 
quite as far as the neck-cells, thus completely separating one or two of the 
archegonia from the main group. 
The jacket-cells themselves showed some interesting features. The 
cytoplasm is always densely granular and stains exactly like the cytoplasm 
of the egg. The nuclei are very conspicuous and stain much more intensely 
than those of the other sterile cells of the prothallium. The jacket-cells at 
the base of the archegonia are small and are crowded closely together, while 
those extending up between the archegonia vary considerably as to their 
size ; some growing to fully half the size of the archegonium. By the time 
that the archegonia are mature, nearly all of the jacket-cells are multi- 
nucleate. All stages of nuclear division were found in the cells, and they 
showed the characteristics of ordinary normal mitosis. There may be 
as many as five or six nuclei in each jacket-cell. Another conspicuous 
characteristic of these cells was the presence of a large vacuole towards one 
end (Fig. 42). If the larger of the jacket-cells were not multinucleate, they 
would be strikingly like small archegonia. 
It will be remembered that in Sequoia the jacket-cells are very 
irregularly distributed, and that in certain stages it is quite impossible 
to distinguish them from young archegonia. In my work on Sequoia 
(’ 04 ) I pointed out the common origin and general similarity of the 
