1906] OVERTON—THECOTHEUS PELLETIERI 471 
inclined to believe that there is a pause before further divisions occur 
and a growth period of these eight nuclei. Not only do the nuclei 
increase in size before dividing, but the asci also lengthen very much 
and the protoplasm becomes still more vacuolated and foamy (jig. 11). 
Perhaps this increase in size of the nuclei is also correlated with the 
increase in the amount of cytoplasm in the ascus. Eventually each of 
these eight nuclei divides to give sixteen free nuclei, no spores being 
yet delimited (fig. rz). In jig. 11 each nucleus is about as large as 
one of the daughter nuclei in fig. 8. These nuclei certainly show a 
marked increase in size over those of fig. 10. It will also be observed 
that the nuclei are irregularly arranged in the central region of the 
sporeplasm. Each of these sixteen nuclei undergoes still another 
division, resulting in thirty-two free nuclei being found in the ascus. 
No figure representing this thirty-two nucleate stage has been drawn, 
although the nuclei were seen in the preparations. ig. 6 represents 
a portion of such a stage. The nuclei here are also very much 
smaller than in jig. 71. 
In Ryparobius BARKER (:03, :04) finds that the number and 
size of the spores vary in different asci. More than two hundred 
were normally found in a single ascus, but as few as sixteen have 
been seen. In Ryparobius successive nuclear divisions occur 
rapidly, until sixty-four free nuclei are formed. These become 
regularly grouped in a dense granular mass of protoplasm around the 
periphery of the ascus. Other series of divisions now usually occur, 
and eventually uninucleate spores are formed. In Thelebolus (RAM- 
Low :06) many nuclei arise in the ascus, about each of which a spore 
is delimited, as described by HARPER. 
In Thecotheus the spores are delimited from the homogeneous 
central portion of the cytoplasm immediately after the formation of the 
thirty-two nuclei. So far as I have been able to observe, the entire 
process of spore delimitation is accomplished by means of the kino- 
plasmic fibers which form the astral radiations of the central body. 
The nucleus becomes pointed or beaked, bearing a central body at its 
outer end, from which the kinoplasmic radiations extend (fig. 6). 
The chromatin lies freely in the nuclear cavity, apparently connected 
with the central body. The process of spore delimitation si, ones 
ently precisely like that described by Harper for Erysiphe communis, 
