352 
MICHAEL LEVINE 
are found in each cell. The character of the branching and the con- 
tinuity of the stipe and gill hyphae are clearly shown. 
We have then in the differentiation of the pileus and the upper 
portion of the stipe region of Coprinus micaceus first the formation of a 
palisade layer of ridges of cells for each pair of hymenial surfaces which 
line the cavity between two adjacent gills. The gills are strictly 
endogenous in origin. There is no general annular gill cavity as 
described by Hoffmann, De Bary, Atkinson, and others, and no annular 
hymenial primordium. 
As the horizontal diameter of the carpophore increases we find 
that the differentiation of the pileus and lamellae progresses centrifu- 
gally. As the growth progresses the distances between the lamellae 
primordia increase and new gill primordia arise between the old ones 
as shown in figure 13. 
Further Development of Pileus and Stipe 
The peripheral layer of the pileus which was originally composed of 
cylindrical hyphae capped by one or more oval cells now becomes 
modified. The cylindrical cells of the earlier stages become oval. 
Stages shown in figures 8, 13 represent later stages in the development 
of the pileus. The peripheral layer is now made up of a few cylindrical 
cells nearly all of which are globular and gelatinous. The change in 
form takes place from the outer toward the inner cells as Brefeld (1877) 
described. The thickness of the layer is greater over the apex of the 
pileus and decreases as it approaches the base of the young carpophore. 
The structure of the pileus proper has undergone a marked change. 
The fine compactly coiled hyphae seen in the earliest stages have become 
much less compact so that the individual cells are more distinct. The 
hyphae widen and the spaces between them become larger. They are 
nevertheless still intertwined and show no definite direction of growth. 
In the lower central portion of the pileus which lies in close proximity 
to the stipe region the hyphae also interlace yet many may be traced 
" directly into the stipe below while others may be traced directly upward 
to the periphery of the pileus. The hyphae near the upper surface 
of the pileus give rise to short, stubby, vertical branches consisting 
of a longer terminal cell and one or two shorter ones below. These 
branches lie parallel to each other and form a palisade layer over the 
pileus {fig. 15) below the outer peripheral layer. This structure is 
similar to that described by Fayod (1889) and later by Fischer (1909). 
