320 Massee and Salmon. — Researches on 
class Hemiasci , of which it alone constitutes the division 
Carpohemiasci , and from it Brefeld considers that the whole 
of the Carpoasci — Discomycetes and Pyrenomycetes — are de- 
rived. His principal reasons for so doing are based on the 
variability shown in the size of the organ containing the 
spores — called an f ascus-like sporangium 5 by Brefeld — as 
also in the number of the contained spores. These characters, 
however, are not more pronounced in Thelebolus than in 
Ryparobins , which Brefeld admits as a true Discomycete ; 
in fact, in many genera having polysporous asci both in the 
Discomycetes and Pyrenomycetes the variability in the size 
of the ascus and in the number of the contained spores is 
as great as in Thelebolus : Ryparobius, Comesia , Tromera , 
Fracchiaea , and Coronophora are examples of such genera 
(cf. Figs. 4 6, 47). 
A distinction of primary importance overlooked by Brefeld 
is found in the fact that a sporangium is multinucleate from 
the first, whereas an ascus is at first uninucleate. The spore-con- 
taining organ in Thelebolus is at first uninucleate. Further, at 
maturity the spores are ejected in a mass through a definite 
opening at the apex, exactly as is the case with the asci of some 
species of Ryparobius ; whereas in the Zygomycetes the spores 
escape through the irregularly ruptured wall of the sporangium, 
as in Mucor , or the sporangium is shot off with its contained 
spores, as in Pilobolus. For the reasons given above we con- 
sider the spore-containing organ in Thelebolus to be a typical 
ascus, and shall speak of it under that name in future. 
Brefeld considers that the parenchymatous wall completely 
surrounding the ascus in Thelebolus is homologous with the 
weft of vegetative hyphae at the base of the sporangiophore 
in Mortierella Rostajinskii, and that the long stem-like spor- 
angiophore in the last-named species is represented in a much 
reduced condition as a single large cell at the base of the 
ascus in Thelebolus . Respecting the covering of the ascus 
in Thelebolus , it may be said that morphologically it agrees 
in every detail with the protective portion known as the 
ascophore in Ryparobius ; it also agrees with the undifferen- 
