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48 the internal surface of it. Three is the largest number of nucleoli which I have observed in other nuclei, and Schleiden has in some very rare instances seen four in plants. If, however, they are only the contents of the nucleus, and not nucleoli, it must be allowed that they differ very much from the contents of almost all other nuclei, which are generally yellowish, and made up of extremely minute granules. The only exception which I have met with was that already mentioned respecting the nucleus of the adipose cells in the cranial cavity of a young carp. This last point seems therefore rather in favour of the germ-vesicle being regarded as a young cell.

When the whole of the above detailed evidence is reflected upon in connexion, it will be seen that it is as yet impossible to decide the question as to whether the germinal vesicle be cell or nucleus. The opinion that the vesicle is to be regarded as a cell-nucleus, seems for the present to have the ascendancy, inasmuch as the observations upon the first and most important point, viz. the prior existence of the germ-vesicle to that of the yelk-cell appear to be in favour of that view. The sub-