ENTRY OF ZOOXANTHELL® INTO OVUM OF MILLEPORA. 705 
to the surface of the egg, was of a like structure, but some of 
its chromatin granules were of increased size, and as a whole 
seemed to have contracted away from the nuclear surface for 
some little distance (fig. 11). I could distinguish no nuclear 
membrane in this case. 
In ova that were ready to be spawned, or had actually been 
so, the germinal vesicle, now without any semblance of 
spherical form, and lacking a definite membrane, though 
contrasting sharply with the cytoplasm, lay close to the 
exterior, beneath a slight depression on the surface ot the 
egg. It exhibited some remarkable features. The granules 
of chromatin were confined to certain areas and in many cases 
were of large size and few in number (figs. 12, 15). In several 
instances there were found, scattered about in the nucleus, in 
half-a-dozen or so groups, evidently without any regular 
arrangement, deeply-staining fragments which had a ten- 
dency to exhibit a form suggestive of minute tetrads (fig. 14). 
No achromatic structures were revealed, but, as at other 
times, the necessity for a supply of suitably fixed material, on 
which to confirm the appearances presented, was felt. In 
several ova deeply-staining granules, sinrilar to those in the 
nucleus, were observed here and there in the cytoplasm, 
suggesting strongly that these latter may be cast out to some 
extent. 
Ova that had been liberated possessed a rather uniformly- 
vacuolated structure, but in a certain instance compact cyto-’ 
plasmic areas lay scattered throughout the vacuolated sub- 
stances. This ovum had not the peripheral nucleus recorded 
of the previous stage, but beneath a slight depression in the 
surface of the egg, just where one would expect to find it, 
there was a patch of the more compact protoplasm containing 
two groups of numerous chromosomes (fig. 15). No traces of 
a spindle could be seen between them; the axis of such, if it 
existed, would be tangential and not radial. Another ovum 
had a similar general structure, but contained some half-a- 
dozen chromatic bodies in as many of the islands (fig. 16). 
Five of these were compact and reticulate in structure, the 
