Humaria rtitilans, Fries. 
*2 M 
3 / 
The ascus-cell, or cell from which the spore-containing part of the 
ascus grows out, is semicircular in section. A small projection, rich in 
cytoplasm, is formed from it, and grows actively, pushing up among the 
paraphyses and the bases of the older asci. Often the convex surface of 
the ascus-cell faces to one side or directly towards the hypothecium, and 
the projection may become much curved. Finally it assumes the character- 
istic shape of the ascus, and either before or after fusion the nuclei of the 
ascus cell pass into it. 
Frequently the terminal cell cut off from the ascogenous hypha con- 
tinues its growth (Fig. 12), giving rise, in the usual way, to another ascus, 
the terminal cell connected with which may in turn develop further (Fig. 13). 
It at first appeared that, in such cases, the nuclei of the new ascus were 
necessarily of the relationship of cousins. But, since the publication of my 
preliminary note on H. rutilans (20), another process has been observed. 
The growing terminal cell often lies in contact with the stalk-cell of the 
same ascus, and may become united to it by an H-connexion (Fig. 14). 
The nucleus of one of these cells may then migrate into the other (Fig. 15). 
If this takes place, the relationship of the nuclei of the new ascus is not 
necessarily close. It was not possible to ascertain whether such migration 
is of general occurrence. It was only observed once, and, in that case, the 
nucleus was passing from the terminal cell into the stalk-cell (Fig. 1 5); but, 
where proliferation has taken place, an H-piece was often found, and it was 
usually impossible to identify a nucleus in the stalk-cell of the corresponding 
ascus. Sometimes it is from the stalk-cell that the new hypha arises 
(Fig. 14). 
The Meiotic Phase. 
Very soon after the young ascus-cell has been cut off, its two nuclei 
enter independently upon the prophases of the first division. The stainable 
material of the nucleus forms a fine thread-work and becomes aggregated 
towards one side of the nuclear membrane forming the first contraction figure 
(Fig. 16), as has been described for the spore mother-cells of higher plants. 
As this contraction passes off the thread thickens, and becomes more 
or less equally distributed (Fig. 17). A certain degree of polarity is some- 
times observed (Fig. 18), the emptier part of the nucleus being remote from 
the region of the previous contraction. 
As the thread distributes itself over the nuclear cavity, indications 
of a longitudinal split are here and there observed (Fig. 17). This becomes 
increasingly evident (Fig. 18), until the thread appears to be double along its 
whole length (Fig. 19). 
Throughout these mitoses, chromomeres could not be distinguished, 
though the thread has frequently a granular appearance which no doubt 
indicates the usual arrangement of its constituents. 
Before the longitudinal fission is complete, the two nuclei fuse, forming 
