Pe ee ee ee eT ee Se eT ee ee ee ee ee eee 
ee ee 
1910] SAXTON—WIDDRINGTONIA 43 
a distinctive structure as is normally the case, while one of the sterile 
nuclei is clearly larger than the other and is also distinguished struc- 
turally from it. This also is unusual and suggests the possibility that 
this larger cell might have eventually taken the place of the tardy 
body cell. - 
The other two cases figured which seem to be abnormal are both 
taken from archegonia occurring in prothalli in which the pollen tube 
had lost its contents, but in which no proembryo was evident. Both 
might conceivably be taken to represent stages in the fusion of sexual 
nuclei. Fig. 45 shows an archegonium which was unhesitatingly 
considered to contain the sexual nuclei in contact, but on examination 
of these nuclei with a more powerful objective they were found to 
have the structure indicated in fig. 45a. The whole of the contents — 
seems to consist of homogeneous and rather dense nuclear plasm 
except for the four nucleoli (?).__ Each of these nucleoli ( ?) consists of 
a membrane from the inside of which a plasmic strand has contracted 
on which are regularly arranged about six (three or four in optical 
section) very deeply staining bodies, of the shape and size figured. 
It is suggestive that the number of these bodies in each nucleolus ( ?) 
should be the same as the haploid number of chromosomes. It is 
also suggestive that two of these nucleoli (?), differing only in size, 
should be present in each of the fusing nuclei, if such they are. 
Figs. 46a and 46 are two successive sections of the same arche- 
gonium nucleus. The structure is so strikingly different in the two 
that it is difficult to believe they are actually parts of the same nucleus; 
but the fact is clear. In each section all the deeply staining structures 
(chromatin granules? and nucleoli?) have been figured, whether 
or not they occur in the same optical focus. 
Beyond the suggestion made above, I have no opinion to offer 
on these figures. Since they occur at such an interesting dec of the 
life history it seems desirable to place them on record. 
8. General 
Since much variation has been noticed among the Cupressineae 
in the time elapsing between pollination and fertilization, it is inter- 
esting to compare Widdringtonia in this respect. The chief point 
of interest is that although a very long period intervenes between 
