In addition to this, there are numerous deeply stained granules scattered about the two figures which resemble exactly the granules of typical nuclei.
All these bodies occupy the place of an ordinary nucleus, they stain like an ordinary nucleus and are as sharply defined as an ordinary nucleus.
There is present around some of these, especially those situated in the yolk, the network of lines of the yolk described by me in a preliminary paper[82], and I feel satisfied that there is in some cases an actual connection between the network and the nuclei. This network I shall describe more fully hereafter.
Further points about these figures and the nuclei of this stage I should like to have been able to observe more completely than I have done, but they are so small that with the highest powers I possess (Zeiss, Immersion No. 2 = 1/15 in.) their complete and satisfactory investigation is not possible.
Most of the true nuclei of the cells of the germinal disc are regularly rounded; those however of the yolk are frequently irregular in shape and often provided with knob-like processes. The gradations are so complete between typical nuclei and bodies like that shewn (Pl. 6, fig. 8c) that it is impossible to refuse the name of nucleus to the latter.
In many cases two nuclei are present in one cell.
In later stages knob-like nuclei of various sizes are scattered in very great numbers in the yolk around the blastoderm (vide Pl. 7). In some cases it appears to me that several of these are in close juxtaposition, as if they had been produced by the division of one primitive nucleus. I do not feel absolutely confident that this is the case, owing to the fact that in the investigation of a knobbed body there is great difficulty in ascertaining that the knobs, which appear separate in one plane, are not in reality united in another.
I have, in spite of careful search, hitherto failed to find amongst these later nuclei cone-like figures, similar to those I found in the yolk during segmentation. This is the more remarkable since in the early stages of segmentation, when very few nuclei are present in the yolk, the cone-like figures are not uncommon; whereas, in the latter stages of development when the nuclei of the yolk are very common and obviously increasing rapidly, such figures are not to be met with.
In no case have I been able to see a distinct membrane round any of the nuclei.
I have hitherto attempted to describe the appearances bearing on the behaviour of the nuclei in as objective a manner as possible.