LEVINE: CyTOLOGY OF HYMENOMYCETES 155 
ameter is several times that of the nuclei in the subhymenium. 
The fusion stages are abundant and easily studied. Thechromatin 
in the nuclei before fusion loses its reticulated structure and a 
number of strands appear (PL. 5, FIG. 70). The nuclei in fusing 
become appressed upon each other and the nuclear membranes: 
disappear in the region of contact. We have thusa two-lobed stage 
(PL. 6, FIG. 18) which lasts for some time, showing that the surface 
tension does not operate to round out instantly the united masses: 
of the fusing pair, as might be the case if they were merely vacuoles. 
The nuclear membranes, however, form a continuous boundary 
(PL. 8, FIG. 47, 48) for the combined nuclear cavities and the con- 
striction in the plane of fusion gradually disappears. The method 
of union of the chromatin masses is not easy to make out. The 
strands soon become mingled so as to be indistinguishable as to 
their origin. 
I am inclined to believe, howéver, that the union is nothing 
more than the approximation of the chromatin strands bringing 
them into close contact with each other side by side (PL. 8, FIG. 46). 
At any rate the chromatin masses from the primary nuclei become 
so intermingled as to leave no visible evidence of their two-fold 
origin at this stage. The nucleoles approach, come in contact 
with each other, and eventually fuse (PL. 8, FIG. 49), forming a 
proportionately larger mass. 
The basidium continues to grow and larger vacuoles appear 
in its cytoplasm. The secondary nucleus lies in the center of 
the basidium and goes through a resting period. At this stage 
I have also observed a dense oval body which stains red, lying in 
various positions in the basidia of Boletus granulatus, B. albellus, B. 
versipellis, B. indecisus, and Strobilomyces strobilaceus. In B. 
albellus, this body is sometimes found in the upper part of the 
basidium. Radiating from it are long strands of kinoplasm. In 
this species (PL. 7, FIG. 61) and in B. granulatus I have also found 
a similar structure lying between the basidium wall and the nu- 
cleus. In B. versipellis the body lies near the nucleus and resembles 
more or less the archoplasmic masses figured by Wager (1894) for 
Mycena galericulata. I have not been able to connect this body 
with the processes of nuclear division and I have no proof that, as 
Wager holds, it is the origin of the centrosomes and karyokinetic 
figures. 
