Sands—Spore Formation in Microsphaera Alni. 747 
in the nuclei of the vegetative mycelium (Figs. 1-3) ; it is con¬ 
spicuous in the ascogone (Fig. 4) and ascogenous hyphae, and, 
with the exception of the primary nucleus where it is some¬ 
times obscured by the abundant chromatin content, it is a 
prominent feature of the nuclei of the ascus, both in the rest¬ 
ing condition and in division. Finally, it is present during 
spore formation and in the resting spores. 
The chromatin is in every case plainly connected with the 
central body, either by direct contact or attached by means of 
kinoplasmic fibers. In the larger nuclei the central body lies 
at the apex of a cone of chromatin strands, while in the small¬ 
er nuclei, although the chromatin is plainly attached to the cen¬ 
ter, the strands cannot be made out, and it appears evenly gran¬ 
ular. 
The center is always an extranuclear body, and my obser¬ 
vations differ radically from those of Maire and Guilliermond 
on this point. In polar and oblique views it may, to be sure, 
appear to be within the nuclear membrane, and I am inclined 
to suspect that, as some of their figures seem to suggest, the in¬ 
tranuclear centers described by Maire and Guilliermond may 
be accounted for in this way, or the centers may have been 
actually drawn into the interior of the nucleus as a result of 
poor fixation. Their descriptions of spindle formation, by the 
division and migration of the centers and the differentiation 
of spindle fibers, agree with the process observed in Micro¬ 
sphaera, and it is to be noted that when the spindle is complete 
the centers at the poles are described by them as on or very 
near the nuclear membrane. However, Maire’s description of 
the formation ( of the polar aster from cytoplasmic fibers which 
radiate from the nucleus is entirely different from anything I 
have found in Microsphaera , where the asters consist of kino¬ 
plasmic rays formed about the central body just before divi¬ 
sion occurs. 
The synaptic mass, as described by these authors, has no such 
definite position in the nucleus as in Microsphaera. The pres¬ 
ence of the central body, which is in continuous connection 
46—S. & A. 
