Notes. 
485 
before they begin to segment. The principal changes which occur 
during the interval are, first, in the rapid increase in the thickness of 
the peripheral cell wall, and, secondly, in the more regular arrange- 
ment of structure exhibited by the protoplasm. The alveolar, or 
foam character is extremely clear, and the chromatophores, which by 
this time have become very prominent, are noticed to be situated in 
the angles formed by the convergence of the foam walls ; they are 
often bent and otherwise distorted, and so accommodate themselves 
to the structural condition of the foam. Other granules, which stain 
deeply, and probably represent food reserve of a proteid nature, are 
also abundantly scattered through the cytoplasm. 
The first segmentation-division resembles, in a general way, the 
oogonial nuclear divisions already described, and the polar areas 
become similarly cleared of granules. The achromatic threads form- 
ing the polar radiations are very clearly seen to be attached to the 
foam-like structure of the cytoplasm, and indeed, in some cases, 
insensibly to pass into it. At other times fibrils end on granules (or, 
perhaps, on the protoplasmic lining of the granules), and sometimes 
again a fibril may fork, and its branches end either on granules or 
on the foam angles. The inference to be drawn from these facts 
seems to be that the radiations are the result of a change — a differ- 
entiation — in the protoplasm as it already exists, and that they do not 
owe their origin to the presence of any special ‘ spindle-forming sub- 
stance/ by virtue of which they may be supposed to develop and 
‘grow’ as new structures in the cell. We propose, however, to 
discuss the general bearings of our observations on this and on other 
questions of theoretical interest in a future memoir, in which the 
evidence for our views will be set forth in detail. 
When the achromatic nuclear spindle appears, it also, as in the 
oogonial mitoses, is intranuclear, and it is often separated from the 
well-defined persistent nuclear wall by a clear space. The chromo- 
somes, when assembled on the spindle, at the equator, are seen to be 
twice as mmerous as in the oogonial nuclei, i. e. seen in profile we 
counted them as twe?ity in number. We were unable to distinguish 
any such grouping of the chromosomes as would lead to the conclu- 
sion that the chromosomes of the male and female nuclei respectively 
had so far preserved their original identity as to appear in the form of 
two separate groups. The long interval of time which, in Fucus, 
elapses between fertilisation and the first nuclear division possibly 
