140 Trow . — Observations on the Biology and 
eccentric, and communicated with a long tube-like vacuole 
in its stalk. It soon took up a central position, increased 
in size, and was apparently cut off from its continuation 
in the stalk. In all probability, though the axile vacuole 
of the stalk disappeared, the limiting layer of protoplasm 
persisted, as the narrow slit-like extension of the vacuole 
in the direction of the stalk suggests in Fig. 4. This slit 
appeared and disappeared several times, and the impression 
created was as if two bands of protoplasm were very slowly 
creeping up the stalk into the oogonium. Light patches 
were to be noted in the dense parietal layer of protoplasm 
of the oogonium, and these were possibly due to the presence 
of vacuoles. Although the hyphae finally almost completely 
emptied themselves into the gametangia, the peripheral mass 
of protoplasm did not increase as greatly either in quantity 
or density as might be expected. No doubt active metabolic 
changes were going on which led to alterations in the mass 
relations of the substances concerned. When the basal wall 
was produced, the vacuole was relatively small. 
This oogonium was kept under continuous observation, 
being examined at intervals of ten minutes for the next seven 
hours without any very striking change becoming apparent. 
During this period, however, it was noted that the oil-globules, 
which at first were very small and numerous, became much 
larger, the cell-wall became thicker, the pits making their 
first appearance at 8.35 p.m., while the vacuole suffered many 
changes of form and gradually increased in size at the expense 
of the peripheral layer of protoplasm, whose density, however, 
did not very perceptibly increase. Irregular heapings of the 
peripheral layer were noted, once at the apex of the oogonium, 
another time on the side. The clear spaces in the parietal 
layer of protoplasm were seen to persist throughout the whole 
of this time. They were lost to sight at times, or perhaps 
actually disappeared. In one or two cases they appeared 
to fuse ; in one very clear instance three of them came 
together in a row, joined up to form one, and the whole then 
disappeared. Some very curious vacuoles were seen, each 
