FAULL: DEVELOPMENT OF ASCUS. 
79 
Berlese (’99) investigated the sporogenesis of Tuber brumale. 
His results in the main corroborated those obtained by Gjurasin and 
Harper. He expressed the opinion that the astral rays determine 
the formation of the plasma membrane of the young spore. 
The only other work to be noted in this connection is that of 
Errera and Guilliermond. Errera (’82) demonstrated for the first 
time the presence of glycogen in the epiplasm. It occurs in a semi¬ 
fluid, amorphous, strongly refractive form, the reactions of which are 
identical with those of animal glycogen and the function of which 
is likewise taken to be nutritive. Guilliermond (: 03, : 03b) has 
recently pointed out the presence of certain granules in the asci of 
Ascobolus marginatus , the Aleurieae, the Helvellineae, etc., and in 
the spores of Peziza coccinea , which he, too, considers to be reserve 
matter, the same as the “ corpuscules metachromatiques ” or “granu¬ 
lations basophyles ” described by him (: 02) in the yeasts and moulds, 
and very like, if not the same as, Biitschli’s “grains rouges” and 
Babe’s “ corpuscules metachromatiques ” found by them in bacteria 
and the Cyanophyceae. 
From the foregoing it is quite evident that the origin and cytology 
of the ascus are known in but a small number of forms, and on these 
are based generalizations for the entire group. Briefly, it is con¬ 
sidered that the ascus is an outgrowth of the penultimate cell of the 
recurved tip of an ascogenous hypha, that it at first contains two 
nuclei which later on fuse, that there follows a series of mitotic 
divisions, that finally the spores are cut out of a homogeneous plasma 
by a membrane formed by the fusion of the astral rays of the last 
generation of nuclei, and that the growing spores are nourished by 
a food supply which is, at least partly, in the form of glycogen and 
an unknown substance, the “corpuscules metachromatiques.” 
The investigations, the results of which are presented in this 
paper, were undertaken in the hope of extending our knowledge of 
the ascus to a number of forms hitherto unexamined. A wider 
knowledge especially of the earlier stages in the development of the 
ascus and of the immediate details in the forming of the spores 
seems desirable because of the light that may be shed not only on 
the question of the affinities of the Ascomycetes among themselves, 
but also on the larger question of the affinities of the group as a 
whole. 
Probably the most favorable forms that have come under observa- 
