228 BOTANICAL GAZETTE [OCTOBER 
achromatic spindle makes its appearance. This arises as two 
flattened, dome-shaped prominences on opposite sides of the 
nucleus. These seem to inclose the nucleus completely, and at 
their summits can usually be seen two spherical bodies, the centro- 
spheres, each with a dark center, the centrosome, around which 
there is a series of cytoplasmic radiations (jigs. 5,8, 71). Some- 
times there is an outer granular zone near the limit of the radia- 
tions ( figs. 8,24). Thus it seems that the spindle originates from 
the two opposite centrospheres. The spindle usually arises on 
the two flattened sides of the nucleus ( figs. 5, 10, 12), but some- 
times it originates on the ends of the long axis of the nucleus. It 
is nearly always very much rounded and flattened at first, except 
in cases of long narrow cells, in which it seems to be pointed from 
the very first. In the younger stages the radiations are often 
not very marked, in other cases they are very distinct and very 
thick but few in number. In case the spindle is formed on the 
ends of the long axis of the nucleus it cannot be seen as early 
as usual, since it then lies very close to the nucleus ( fg. 7). 
Although the centrospheres generally separate quite early and 
take their position on opposite sides of the nucleus, they may 
sometimes be considerably delayed. Fig. 9 seems to be such a 
case, where the chromatin band is well formed but the two cen- 
trospheres are still close together and their centrosomes have 
begun to divide. This figure may be explained by supposing 4 
late separation of the centrospheres and a precocious division of 
the centrosomes. There are beautiful, delicate radiations pass- 
ing out into the cytoplasm. In some cells the incept of the 
spindle remains dome-shaped and very much flattened for a long 
time, and frequently no bodies can be seen which look like cen- 
trosomes. It need not be implied, however, that centrosomes 
are not present in such cases. In cells of about the same age 
the spindles are often becoming pointed and show a centro- 
sphere in close contact with the spindle fibers, and having well 
developed radiations around the poles ( figs. rz, 73). In jig. 10 
there is a system of streams of cytoplasm passing out from the 
young spindle to the cell wall. These are no doubt ordinary 
