Admitting the existence of the two extreme processes of nuclear formation, I wish to shew that my results in Elasmobranchii tend to demonstrate the existence of intermediate steps between them. The first figures I described of two opposed cones, appear to me almost certainly to represent nuclei in the act of dissolution; but though a portion of the nucleus may stream out into the yolk, I think it impossible that the whole of it does[93].
Footnote 93: After Strasburger's observation it must be considered very doubtful whether the streaming out of the contents of the nucleus, in the manner implied in the text, really takes place.
I described these bodies in two states. An earlier one, in which the two cones were separated by an irregular row of deeply stained granules; and a later one in which a furrow had already appeared dividing the cones as well as the cell. In neither of these conditions could I see any signs of the body vanishing completely. It was as clearly defined and as deeply stained as an ordinary nucleus, and in its later condition the signs of the streaming out of material from its pointed extremities were less marked than in the earlier stage.
All these facts, to my mind, point to the view that these cone-like bodies do not disappear, but form the basis for the new nuclei. Possibly the body visible in each cone in the later stage, was the commencement of this new nucleus. Götte[94] has figured structures somewhat similar to these bodies, but I hardly understand either his figure or his account sufficiently clearly to be able to pronounce upon the identity of the two. In case they are identical, Götte gives a very different explanation of them from my own[95].
Footnote 94: _Entwicklungsgeschite der Unke_, Pl. 1, fig. 18.
Footnote 95: As I before mentioned, Strasburger (_Zellbildung u. Zelltheilung_) has represented bodies precisely similar to those I have described, which appear during the segmentation in the egg of _Phallusia mammillata_ as well as similar figures observed by Butschli in eggs of _Cucullanus elegans_ and _Blatta Germanica_. The figures in this monograph are the only ones I have seen, which are identical with my own.
A second of my results, which points to a series of intermediate steps between division and solution of the nucleus, is the distribution in time of the peculiar cone-like bodies. These are present in fair abundance at an early period of segmentation, when there are but few nuclei either in the blastoderm or the yolk. But at later periods, when there are both more nuclei, especially in the yolk, and they are also increasing in numbers more rapidly than before, no bodies of this kind are to be seen. This fact becomes the more striking from the lobate appearance of the later nuclei of the yolk, an appearance which exactly suits the hypothesis of the rapid budding off of fresh nuclei.