250 Carruthers . — Contributions to the Cytology of 
drawn out behind into a fine thread, by means of which it remains attached 
to the nucleus for a considerable time, but never at a great distance 
from it. 
A relationship has been suggested between such bodies and the 
chromidia cast out during Gametogenesis in the lower animals, but it is at 
present still uncertain whether any special significance with regard to 
meiosis can be attached to the process. If the extrusion of a part of the 
chromatin could be shown to be a normal accompaniment of meiosis and 
to form an integral part of the process, it might perhaps be held that not 
only the qualitative halving of the chromosomes, but the loss of some con- 
stituent of the nucleus was necessary to the development of sexual cells. 
In Helvetia , however, meiosis takes place many cell generations before any 
fusion, and sexual cells are never differentiated. In such a case it is possible 
that the chromatin bodies are no more than masses of nutritive substance, 
for which the nucleus has no further use. Against such a view is to be set 
the fact that the process is as well defined and elaborate in the Ascomycete 
as in the Angiosperm, and such a phenomenon occurring with striking 
similarity in widely separated groups is suggestive of some deep-seated 
analogy. 
In drawing conclusions from these facts, it must, however, be remem- 
bered that Helvetia is certainly a reduced form, and the expulsion of the 
bodies may be only a vestigial phenomenon. Even if it occurred in the 
ancestral type, which may reasonably be assumed to have possessed sexual 
organs as well developed as those of Pyronema , it is difficult to see what 
necessary connexion existed between the extrusion of chromatin masses 
and meiosis. 
Summary. 
1. There are no sexual organs in Helvetia crispa , but fusion of nuclei 
in pairs occurs in certain hyphae of the hypothecium, and these cells 
produce the ascogenous hyphae. 
2 . There is evidence that mitoses in the vegetative and ascogenous 
hyphae show respectively two and four chromosomes. 
3. A second fusion occurs in the formation of the ascus, but the 
chromatin of the two nuclei remains distinct until the spireme stage. 
4. The first and second divisions in the ascus constitute a meiotic 
phase of the type described by Farmer and Moore. 
5. During the early stages of meiosis chromatin bodies are extruded 
from the nucleus. 
6. In the first two divisions four chromosomes appear on the spindle. 
7 . The third division is brachymeiotic ; in the prophase four chromo- 
somes appear and two pass to each pole. 
