304 BOTANICAL GAZETTE [ocroser 
Fischer in 1885 goes somewhat more deeply into detail regard- 
ing the structure of the nucleus in Exoascus. According to his 
observations the nucleus is a round granular mass in which 
smaller and darker rounded bodies appear just before division. 
Next a spindle is formed, consisting of four threads converging 
slightly toward the poles. In the equatorial plane of the spindle 
four chromosomes now appear, which divide and pass to the 
poles of the spindle, where they form themselves into daughter 
nuclei. This description is of course crude, as were the methods 
of observation upon which it was based. Gjurasin (13) in 1893 
published the first detailed account of karyokinesis in the 
Ascomycetes. It is based upon a study of Peziza vesiulosa. 
He describes the nucleus as consisting of a distinct round gran- 
ular nucleolus surrounded by a layer of hyaloplasm in which an 
indistinct network is present. At the time of division the 
nucleus elongates, the nucleolus becomes eccentric, the chro- 
matin aggregates into small masses, and two centrosomes with 
radiating stria appear. Between these are drawn the nearly 
parallel threads of the spindle. The chromatin masses collect 
in the equatorial plane of the spindle and divide, and the 
daughter chromosomes very quickly seek the poles and soon i 
surrounded by new nuclear membranes, the membrane of the 
parent nucleus having meantime disappeared. In these daughter 
nuclei the nucleoli appear after the formation of the membrane, 
and with their appearance the mother nucleus, which up t ss 
time has persisted lying free in the cytoplasm, disappeats- 
Second and third divisions occur in like manner. Gjurasin seit 
that he spent two years in the search for these karyokineti¢ 
structures, obtaining his final results by means of the Herman? 
and Flemming methods of fixing and staining. 
Harper (5) in 1895, by methods similar to those 
Gjurasin, observed karyokinesis in Peziza Stevensoniana . 
and Ascobolus furfuraceus Pers. From studies of these an yer : 
ous allied Discomycetes he concludes that the members of - = 
group are especially favorable for the study of nuclei 1? oe 
ascus. The results of his work may be summarized as follow?" 
adopted by 
