FAULL: DEVELOPMENT OF ASCUS. 
97 
The young spores when first delimited, are much compressed in 
shape, but they soon acquire the oblong shape indicated in figure 57 
(pi. 10). In figure 57 the plasma membrane is completed and the 
nuclear beak has reached its maximum length. This beak has 
become more tenuous than formerly and the chromatin has been 
distributed. 
The centrosome soon breaks from the plasma membrane and the 
beak is retracted. This retraction is preceded by a contraction 
which results in its thickening and in drawing the venter of the 
flask nearer the end of the spore. 
This re-formation of the nucleus is directly followed by its divi¬ 
sion. The division is karyokinetic. The spindle is intranuclear and 
there are asters. In the anaphase stage it elongates beyond the 
limits of the nuclear wall which soon after disappears (pi. 10, fig. 
58). When completed, the daughter nuclei resemble the mother 
nucleus in all respects except in size (pi. 10, fig. 59). The exospore 
has not yet been laid down, though its appearance is now not long 
delayed. 
Septate and Multinucleate Spores. 
Multinucleate spores are generally septate, ISordaria fimicola , 
as we have seen, affords an example of a departure from this rule. 
The spores of Discina venosa are several-nucleated and yet not 
septate, while those of a Thielavia found by Professor Thaxter at 
New Haven, growing parasitically on Isaria, regularly contain four 
nuclei. When first formed, all possess but a single nucleus, the 
increased number arising by subsequent divisions proved in Sordciria 
fimicola to be karyokinetic. 
Septate spores are likewise uninucleate at their origin. This has 
been shown to be the case in various forms examined by the writer, 
such as Massaria vomitoria , Massaria platani , Geoglossum ophi- 
oglossoides and Geoglossum hirsutum , Leptoglossum sp., and Lep- 
toglossum luteum. The spores are nearly spherical when delimited, 
but after the development of the plasma membrane they begin to 
elongate. In course of this growth in length the nuclei divide and 
septa are usually formed after each division, thereby separating the 
daughter nuclei from one another. The nuclei seem to be intimately 
connected with the construction of septa, for septa are formed in 
