Harper . — Cell- Division in Sporangia and Asci. 513 
body is very close to the plasma-membrane, but as the process 
of folding over of the rays continues, the whole figure migrates 
somewhat toward the centre of the ascus, as is seen by com- 
paring the upper two nuclei in Fig. 44. An examination 
of Figs. 44 and 45 shows that the lower nuclei of the series 
tend to be a little in advance of the upper nuclei in their 
development, though this is by no means a general rule. 
Fig. 44 shows stages in the cutting out of the spores from the 
early stages in the displacement of the aster-rays in (a) to 
the completion of the plasma-membrane (/). In d and e the 
enclosure of the spore is not quite complete, and it is seen 
that the last part to be enclosed need not necessarily be 
antipodal to the central body. The shape of the mass first 
enclosed is also seen to be quite variable. In Fig. 44 ( c ) the 
nuclear figure is seen to be at the side rather than at the end 
of an ellipsoidal spore-mass. Of the two spores ( e and f) the 
latter lies somewhat higher in the section and overlaps e , 
though they are drawn as if lying in the same plane. Irregu- 
larities of shape and in the position of the nucleus in the 
forming spore are much more numerous in Lachnea than in 
Erysiphe , and are due no doubt to greater crowding in the 
formation of the eight spores before they become evenly 
distributed in the elongated, relatively narrow ascus, while in 
the broad oval asci of Erysiphe the two to three spores are 
more evenly distributed from the first. These irregularities, 
however, make still more clear the relatively independent 
activity of the aster-rays, for, however the nucleus may be 
placed, they succeed in enclosing in every instance practically 
equivalent volumes of the spore-plasma, as is seen by com- 
paring the size of the spores after they are completely outlined. 
The orientation of the nuclear figures, though tending in 
earlier stages of spore-formation to be radial to the surface of 
the ascus, is extremely varied, as seen in Fig. 46. This figure 
shows also that, though the nuclei are in general rather evenly 
distributed in the spore-plasma, the process can be carried out 
just as perfectly when several nuclei are in close proximity to 
each other, as are the three, b , c , d , in this section. In some 
