46 Wisconsin Academy of Sciences, Arts, and Letters. 
many branches spreading outwards. In the center the hyphae 
are so densely packed that it is impossible to tell whether the 
branches originate from a single hyplia or from several. As a 
number of hyphae from different directions in the substratum 
lie near together at this point it is probable that they arise from 
several. 
The cells are regularly binucleated. The cytoplasmic strands 
are very delicate and form a loose network at the periphery of 
the cell. Very small convex plates are present at the cross wails 
marking the regions of protoplasmic connection between the cells. 
This method of formation of the carpophore was repeatedly ob¬ 
served in the hanging drop cultures. It is probably an adapta¬ 
tion to the culture conditions, especially the small supply of 
nutrient. In larger cultures of agar-agar in Petri dishes I find 
quite another method for the formation of the carpophore. 
In an agar culture in a Petri dish the main hyphae with their 
system of branches can frequently be traced for one or two 
inches. Pig. 16 was made from the end of one of these systems. 
Squares of the agar a little smaller than a % inch cover glass 
can be fixed in Flemming’s weaker solution and then fastened 
to a slide with a film of albumin. Preparations are best stained 
with iron haematoxylin. The stain washes from the agar in the 
iron solution leaving the mycelial hyphae sharply defined so that 
they can easily be studied. 
The main hyphae are formed of very long cells which have 
from five to eleven nuclei that are smaller than in Hypholoma, 
but show the same general structure, they are elliptical with a 
nucleole at one end, finely granular chromatin, and a small body 
which is usually opposite the nucleole. This small body is flat¬ 
tened against the nuclear membrane and takes a very deep blue 
stain. The great regularity of its occurrence and its staining 
qualities have led me to consider this as the same structure as 
the central body which Harper described in the ascospores of 
Erysiphe. The primary branches which arise from the main 
hyphae show great regularity of arrangement. They are formed 
in pairs at one end of every cell or every other cell. They are 
never exactly opposite, one always appearing slightly below the 
other. These branches are approximately of the same size as 
