1896 | THE PHALLOIDEA OF THE UNITED STATES 275 
Of the three layers of the volva, the middle, or gelatinous 
layer, is not one continuous sheet as in the Phallez, but consists 
of as many meridionally arranged masses as the receptaculum 
hascolumns. These gelatinous masses alternate in position with 
the columns and are completely separated from each other by 
the cortical plates (C’, figs. 4, 5, and 6). The cortical plates 
extend from the base to the apex of the egg and connect each 
column of the receptaculum throughout its entire length with the 
outermost, or cortical layer (C). The peculiar arrangement of 
alternating cortical plates and gelatinous masses arises in the 
early differentiation of the egg, as will be shown further on. 
COURSE OF DEVELOPMENT. 
The eggs are borne at the ends of short branches of the 
subterranean mycelial strands. In cases where the egg has 
arisen as an outgrowth on the side of a mycelial strand, the 
Portion of the strand beyond the egg seems to have ceased its 
further growth so that the egg becomes practically seated at the 
end of the strand running into it. The mycelial strands consist 
of two systems of tissues: a central or medullary bundle of fine 
hyphae running in a longitudinal direction, and an outer or cor- 
tical layer of coarser hyphz forming a loose but very interwoven 
Structure, 
The cortical layer of the strand is continued upward in the 
— its outer covering (C, fig. 1). This figure is from a 
median longitudinal section of an egg 1.5™™ long by about Pin 
diameter. The more compact medullary bundle is marked J. 
% the strand, so here, its hypha run in a prevailingly longi- 
udinal direction lying close together. By the double stain used 
iy two layers of the egg are sharply separated from each 
Gack in color as well as by the more open structure of the cor- 
ions hes Although so well marked, still they are in intimate 
. in their region of contact by means of hyphe which 
inter] ay laterally from the medullary layer and branch and 
ba ace with the cortical hyphae and become indistinguishable 
them. In fig. 2 a cross-section of an egg in the same stage 
