the Ascocarp in Ascophanus carneus , Pers. 41 1 
The ascus by this time has taken on the club-shape so commonly found in 
the Ascobolaceae, and resembles very much the figures which Overton 
gives of Thecotheus Pelletieri (24). 
Although material has been fixed at all times of the day, no stages 
have been seen either in the divisions of the ascus-nuclei or in the formation 
of the wall of the spore. Most of the fruits that were examined were, how- 
ever, much too young to show these stages, and those that were old enough 
were not examined in as much detail as the younger ones, so that it is still 
possible that such stages may be amongst the sections, and that such 
processes do take place during the day. The characteristic number of 
spores — eight — is formed in the ascus. 
General Considerations. 
In recent years evidence in favour of the sexuality of the Ascomycetes 
has been rapidly accumulating, and several cases of fertilization, both of the 
normal and of the so-called reduced type have been described. 
Professor Harper has reported normal fertilization by means of male 
and female organs in Sphaerotheca (18, 19), Erysiphe (19), Pyronema (20), 
and Phyllactinia (21), and Blackman and Fraser (6) have confirmed his 
observations on Sphaerotheca . 
The first recorded case of reduced fertilization was described by Black- 
man and Fraser (7) in Humaria granulata. Since then Miss Fraser has 
recorded other similar cases in Lachnea stercorea (14) and Humaria 
rutilans (15), and Miss Welsford a similar process in the development of 
Ascobolus furfur aceus (27). 
Claussen (8) has recently described the state of affairs in Pyronema 
confluens , in which, as he holds, the male and female nuclei, arranged 
in pairs, pass out of the ascogonium into the ascogenous hyphae, and the 
sexual fusion is delayed until the formation of the ascus. From this one 
observation he concludes that in no ascomycete is there more than one 
fusion, and that the rule obtains throughout the group that the sexual 
fusion is delayed until the ascus formation. 
Miss Fraser and Miss Welsford (17) have already pointed out that 
although such a shifting of the sexual fusion is possible, yet there is no 
reason whatever to regard it as the rule, rather than the exception, amongst 
the Ascomycetes. 
In the paper that I have just quoted, the well-authenticated case 
of Sphaerotheca , in which there has been shown to be two fusions, is urged 
against this view of Claussen’s, and also the fact of double reduction, which 
Miss Fraser has observed, in the ascus of Humaria rutilans and other 
forms (15, 17). 
As this theory of Claussen’s is fully discussed by Miss Fraser and 
