Azotes, 
307 
described above are followed by cell divisions. Thus the supernumerary pollen-grains 
are produced by the organization of distinct cells round all the nuclei, whether these 
have been formed in the regular course of mitosis, or by the isolation of irregularly 
distributed chromosomes. 
I can find no evidence of the existence of secondary divisions of the cells such 
as Wille described, nor do my observations give any support to this author’s suggestion 
that a fusion (or non-separation) of primitive mother-cells (Urmutterzellen) might 
occur in those cases in which the additional microspores were very numerous. 
A definite relation appears to exist between the number of chromosomes entering 
into a nucleus, the size of the nucleus, and the size of the cell produced. 
It may be further added that the small cells, with only a few chromosomes 
entering into the composition of their nuclei, develop pollen-walls, which differ neither 
in structure nor in chemical composition (viz. they give the same staining reactions) 
from those surrounding the pollen-grains which have received the normal number of 
chromosomes. 
It will be seen that these facts have an interesting bearing upon the theory of 
the localization of specific characters in particular chromosomes, but the discussion 
of this matter must be left for my full paper upon the pollen development of Fuchsia 
and some other plants. 
RUDOLF BEER. 
CONTRIBUTIONS TO THE CYTOLOGY OF HUMARIA RUTILANS FR. 
(Preliminary Note.) — Hum aria rutilans is a small orange Discomycete occur- 
ring in abundance on sandy soil. It possesses exceptionally large nuclei, the nucleus 
of the uninucleate ascus measuring about 14/1x9/1. 
The ascocarp originates as a tangle of septate hyphae, each cell containing one 
or a few nuclei. Sexual organs are not differentiated. Very early a sheath of rather 
thick-walled cells can be distinguished, and within this ramify numerous hyphae, 
growing upwards till, while the ascocarp is still quite minute, paraphyses and subse- 
quently asci appear. At and rather before this stage two sorts of hyphae can be 
distinguished in the hypothecium by the size of their nuclei, though they do not 
otherwise differ. The larger nuclei are about twice the size of the smaller, and are 
formed by the fusion of these in pairs. This would appear to constitute a process of 
reduced fertilization, or apogamy, quite comparable to that observed in the prothallus 
of Nephr odium, and representing a stage in the reduction of sexuality more advanced 
than that found in Hum aria granulafa, where an ascogonium is organized and the 
female nuclei fuse in pairs. The hyphae containing the larger, or fusion-nuclei, may 
thus be regarded as sporophytic, the others as gametophytic. 
Asci arise from the sporophytic or ascogenous hyphae. The hypha, on reaching 
the subhymenial layer, bends over and its two terminal nuclei undergo simultaneously 
a karyokinetic division in the prophase of which sixteen chromosomes may be counted. 
As first described by Dangeard, a terminal uninucleate and a penultimate binucleate 
cell are now cut off, the latter constituting the young ascus. 
The terminal cell may continue its growth and give rise to a hypha, the penultimate 
cell of which again forms an ascus. The two nuclei of the ascus appear to be, in 
such cases, of the relationship of cousins. 
Each of the two nuclei of the ascus now enters on the early prophases of hetero- 
z 
