474 Farmer . — - On Spore- Formation and 
myself disposed to believe that they do represent linin struc- 
tures rather than structures originating from the more fluid 
part of the nucleus. They may also be occasionally observed 
in the pollen-mother-cells of Lilies at an early period of their 
nuclear division. The straight threads which run from one 
anastomosis to another often appear to be composed of 
a double thread lying side by side ; this peculiarity becomes 
more obvious at a later period, but, as will be seen presently, 
it can hardly, by itself, constitute the longitudinal fission of 
the chromatic elements of the nucleus, and it may further 
possess a totally distinct significance. The nucleus remains 
in the rudimentary and early phase of karyokinesis for a con- 
siderable time, and this is a feature very often met with in 
spore-mother-cells. Thus it would seem from the accounts 
given by Belajeff 1 and by Strasburger 2 that the pollen- 
mother-cells of Larix can continue in a somewhat later phase 
throughout the winter, only completing the process on the 
return of warmer weather. 
The first sign in Fossombronia of renewed activity appears 
in the cytoplasm in the form of centrospheres. These bodies 
arise, -or at least become first recognisable, simultaneously at 
four points on the periphery of the nucleus which are situated 
equidistantly from each other, one being opposite to each of 
the four lobes of the spore-mother-cell. They are exceed- 
ingly well marked, and in preparations stained with Heiden- 
hain’s iron-haematoxylin and afterwards treated with 
orange, they are so clear as to be suitable for demonstration 
purposes (Figs. 2-4). The central part of the sphere is rather 
hyaline, and a minute granule may often be distinguished in 
the middle of it, which I take to be a centrosome. The 
cytoplasmic radiations spread outwards, and may often reach 
the periphery of the cell. Occasionally they are seen to 
terminate in granules, which are sparsely scattered about in 
the cytoplasm. When a number of these granules lie near 
1 Belajeff, Zur Kenntniss d. Karyokinese b. d. Pflanzen. Flora, Erganzungsband 
zum Jahrg. 1894. 
2 Strasburger, Karyokinetische Probleme, Pringsheims Jahrb. XXVIII, p. 166. 
