ATKINSON: THE GENUS ENDOGONE 13 
Empusa (Entomopthora) fresenii, Empusa rhizospora, sepulchralis, etc.., 
Endogone sphagnophila and lactiflua. 
4. Progression in the direction of selection of sex nuclei. In 
Endogone lactiflua one sex nucleus is selected from among all the 
potential ones in each gamete. This illustrates how the situation in 
Dipodascus, Eremascus fertilis and in Endomyces has arisen. This 
situation is presaged in some of the lower zygomycetes in the degener- 
ation of some of the gamete nuclei in Rhizopus, Sporodinia and Zygo- 
rhynchus, if we may accept the account by Moreau (1911, 1913). 
In Endogone sphagnophila there are many potential and many func- 
tional nuclei in the gametangia and these are carried on into the 
young germinating, or progressive zygote. This type illustrates a 
situation which has been retained in those ascomycetes with multi- 
nucleate gametangia as in Monascus, the Gymnoascaceae, Ascodesmis, 
Pyronema, etc. 
5. The postponement or moving forward of the moment of nuclear 
fusion from the gametangia to the new outgrowth, or progressive 
zygote. The examples are the same as those given in paragraph 3. 
In the zygomycete alliance Endogone lactiflua represents the most 
progressive stage in these directions of any known species, unless 
Dipodascus should be regarded as a phycomycete. The sex pair of 
nuclei is organized by the migration of the antheridial nucleus into 
the oogone. The pair then migrates into the new outgrowth where 
the sex nuclei lie side by side in the resting zygote, or fuse, in one 
variety. As Bucholtz (1912) points out there is wanting here only 
the conjugate division of the nuclear pair to parallel the situation in 
the ascogenous hyphae of the true ascomycetes. 
From the situation reached by progression in these directions, by 
members of the zygomycete alliance, there is but a small gap over 
which to bridge in reaching the protoascomycetes. The principal 
steps may be indicated as follows: 
1. Free cell sporulation of the progressive zygote of Endogone. 
This alone would place this zygote in the category of a generalized 
ascus, and Endogone would become a fit member of the protoascomy- 
cetes. Intersporal substance present in the sporangium of some 
phycomycetes during sporulation may possibly presage typical free cell 
sporulation. Other steps toward the true ascomycetes are indicated 
in the following. 
2. The omission of a period of rest by the progressive zygote and 
the immediate free cell sporulation of the same. This step alone 
would reach the level of Dipodascus, Eremascus, Endomyces magnustt, 
etc. 
3. Vegetative growth of the zygote and postponement of free cell 
