Keene—Studies in Zygospore Formation. 1197 
tion of an oily reserve substance are described. These bodies 
are small and numerous in partially mature zygospores but 
later become reduced to one or two large plasmatic bodies sat¬ 
urated with oil. A nuclear disorganization takes place. All of 
the nuclei do not disorganize and, even in the mature zygospore, 
many of the normal but slightly larger nuclei are present. 
The mature zygospore contains a large amount of an irreg¬ 
ularly knotted or densely granular, red-staining substance 
which the writer was unable to explain. It reacted to the 
triple stain much as the mucorin crystals do, but appeared to 
arise from the disorganized nuclei. 
Burgeff (1915) describes briefly the internal changes which 
take place at the time of conjugation and of the formation and 
germination of the zygospores of Phycomyces nitens . At the 
time of conjugation the nuclei become collected at the places of 
contact of the gametes, a large vacuole becomes evident, the’ 
wall is resorbed and the zygospore is established. The nuclei 
are equally distributed throughout the zygospore. No nuclear 
fusions are to be noted. Vacuoles containing oil appear, to¬ 
gether with granular masses which are protein-like reserve sub¬ 
stances. Later the oil vacuoles flow together into a few large 
globules. At two to four months after formation, one central 
oil globule is present. The nuclei lie in the outer layer of 
the non-granular, weakly staining, hollow, cytoplasmic sphere 
which surrounds the oil globule. The nuclei are homogeneous, 
without a membrane and are surrounded by a clear zone. 
Burgeff finds that, at the time of germination of the 
zygospores of one variety, the nuclei are arranged in pairs in the 
periphery. A varying number of the nuclei appear to fuse in 
pairs. In another variety the conjugation of the nuclei ap¬ 
pears to take place before germination. The oil globules be¬ 
come reduced and the cytoplasm becomes vacuolate. As the 
germ tube pushes out, the nuclei undergo mitotic division. 
The single chromatin grain of the nucleus forms simple, small 
chromosomes. The approximate number, determined by count 
and estimation, is twenty-four. They appear to separate into 
groups of twelve and become surrounded by a membrane. 
The present piece of work was undertaken in the hope that 
some further facts concerning these internal phenomena might 
be offered. Furthermore, in view of the work done by Blakeslee 
