BRA CH YM EI OS IS 2 1 7 



he showed the entrance of male nuclei from the antheridium into 

 the oogonium through the trichogyne, and ascertained that there 

 was no fusion of the male and female elements at this stage. The 

 nuclei, however, paired, and when the ascogenous hyphae were 

 budded out from the oogonium, these pairs or synkaryons passed 

 up the ascogenous hyphae. The usual crozier formation occurred, 

 and the two nuclei divided, walls were laid down and the penulti- 

 mate cell contained two nuclei. The only fusion in the life-history 

 was the fusion of the two nuclei in the penultimate cell. The three 

 divisions in the ascus followed, the first was heterotypic and the 

 second homotypic. The third was not brachymeiotic, but a 

 purely equational di\'ision with no further reduction in the number 

 of chromosomes. Claussen considered that the presence of so- 

 called " fusions " in the earlier stages was due to poor fixation, and 

 that some of the nuclei were in a pathological condition. There- 

 fore, on these grounds, the figures described by the brachymeiotic 

 school as " fusions " are regarded as purely artifacts. Practically 

 without exception, the papers which subsequently followed this 

 work placed the same interpretation on the nuclear phenomena 

 displayed by the Ascomycetes, and since there was no early fusion 

 in the life-history the necessity for a second reduction became 

 unnecessary, and Claussen's synkaryons placed this group on the 

 same footing as the Uredinales. 



More recently Bagchee has followed essentially the same inter- 

 pretation for the ascomycete, Pustular ia holarioides. Only the 

 divisions in the ascus were examined. The first heterotypic 

 division was found to follow the telosynaptic scheme of reduction. 

 The di^^loid number of chromosomes in this form are 32, and 16 

 bivalents made their appearance at prophase of the first division. 

 In the next two divisions 16 chromosomes could be counted, i.e., 

 the third division was purely vegetative and not brachymeiotic. 



A somewhat curious compromise has been arrived at for the 

 form Pyronema domesticum by Tandy. He was able to confirm 

 Claussen's description of the general sexual process. This species, 

 like P. confluens, possesses both an oogonium and an antheridium. 

 The entrance of the male nuclei was a fairly prolonged affair, and 

 the claim is made that at the fringes of the oogonium fusion of 



