96 BOTANICAL GAZETTE 
eggs differentiated around dynamic centers (coenocentra), bie the 
specialization of a periplasm in some forms. Perhaps the 
expression of periplasmic development is the cellular envelope w 
finally invests the egg of Araiospora. g 
SUMMARY OF THE INVESTIGATION OF VAUCHERIA. 
The oogonium arises as a process containing dense protoplasn 
with many plastids and nuclei. As the young structure increases i 
size, vacuoles develop in the protoplasm, which consequently forms = 
a peripheral layer next the cell wall. : 
The number of nuclei is variable, but always large, probably 
ranging from 20 to 50. There are no mitoses in the oogonium. — 
‘The oogonium becomes separated from the parent filament by 
cross wall which is developed between two plasma membranes thal 
appear to be formed along the surfaces of flattened vacuoles. 
The oogonium is multinucleate at the time the cross wall is forn 
but even then there is evidence of the degeneration which becon 
much more pronounced later. 
In older oogonia the degenerating nuclei are found chiefly 3 in 
periplasm. They become exceedingly small, the nuclear membr 
disappearing first, and finally nothing remains but granular mat 
apparently nucleolar, which is finally lost in the cytoplasm of th a 
cell. 
A single nucleus survives the general processes of degenerati 
This becomes the gamete nucleus and takes its position near 
center of the egg, which is probably the situation most favora' 
its growth. There is apparently no coenocentrum in the 88 
Vaucheria, but the surviving nucleus frequently lies in a cst 
rather dense protoplasm which may readily represent a Cen’ 
metabolic activity. 
There are excellent reasons for believing that all of the puck 
the young oogonium are potentially gamete nuclei, and that 
selected egg nucleus owes its survival and later growth ¢ enti 
the good fortune of a favorable situation in the cell. — 
The gamete nucleus grows rapidly. until it is finally thi 
times the size of the nuclei in the young oogonium. — 
marked increase in the amount of chromatin, which fills the 
