96 UNIVERSITY OF WISCONSIN STUDIES 
more highly magnified than the other figures in the cut. The 
plate became filled with secondary colonies of this kind con. 
nected by almost microscopic filaments. At d is another type 
in which the colony is almost entirely filament with an oc. 
casional bud-like colony. The filament formation is fre. 
quently limited to fringe-like outgrowths on the margin, as, 
Fig. 6 
shown by the sections of liquefying colonies at ¢ and f. Some- 
times on a plate filled with smooth, round, solid colonies, an 
occasional colony like b or gy may develop. The type of colony 
from an individual culture may be variable and, on a 
single plate, may be found solid smooth colonies, large colonies 
liquefying in the center, and almost any one of the colonies 
shown in Fig. 6. Sub-cultures have been made from the dif- 
ferent types of colonies of a single culture, but these sub- 
