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Transactions of the Society. 
nucleus into the cytoplasm have been described ; much of the 
recent literature I have already reviewed in a previous paper (31/). 
There seems every probability that the so-called “ chromidia 
emitted from the nucleus of germ cells at the bouquet stage, as 
described by writers such as Buchner and Jorgensen, are really 
the cytoplasmic organs — Golgi apparatus and mitochondria — which 
are usually found at that stage in the position where these writers 
figure chromidia. 
Several cases have been described recently of fragments of 
the nucleolus passing, during oogenesis, through the nuclear 
membrane into the cytoplasm, and either dissolving there or else 
giving rise to yolk bodies (34). A somewhat similar process is 
mentioned by Wassilieff (61) in the spermatocyte of Blatta, but 
whether the structures there described are really nucleolar or 
chromatin extrusion, or are cytoplasmic organs is open to doubt. 
It is of interest to note that in the cases of oogenesis recently 
described, the solid substance thrown out from the nucleus into 
the cytoplasm is derived from the nucleolus, and is not regarded 
as interfering in any way with the integral continuity of the 
chromosomes throughout the germ-cell cycle. Further, the 
extrusion appears to be related to yolk formation rather than 
having any special formative effect. It is of course impossible to 
say whether there are any other effects upon the growing oocyte. 
There are, however, certain cases of substances extruded from 
the nucleus, which exert a definite after-effect. The so-called 
“anello cromatico” of Giardina is a case in point (16). Giardina 
found in the oogonium of the beetle Dytiscus that the nucleus 
became differentiated into two parts, the one containing irregular 
granules of chromatin which represent the chromosomes, the other 
of an irregular-shaped mass — the “ anello cromatico.” Such an 
oogonium divides repeatedly. Each time while the chromosomes 
are undergoing either meiosis or mitosis, the “ anello cromatico ’ r 
remains at one side of the cell and passes in its entirety into one 
of the newly-formed cells, so that ultimately only one of the 
sixteen cells into which the oogonium divides contains this 
structure. This cell alone becomes the oocyte, the others give 
rise to nurse cells. The “ anello cromatico ” appears to be com- 
posed of plastin, and to be of a nature similar to the nucleolus. 
Later in the development of the oocyte it breaks up, and long 
before maturity is reached it has disappeared altogether from the 
oocyte. 
Several cases have been described of the nucleolus functioning 
as a germ-cell determinant. Silvestri (53), quoted by Hegner (23\ 
studied the development of the ova in both monembryonic and 
poly embryonic hymenopterous parasites. He found in each case 
a germ-cell determinant which he termed the “ nucleolo,” and he 
considers it to be derived from the plasmosome of the oocyte 
