742 Wisconsin Academy of Sciences, Arts, and Letters. 
At a later stage, the chromatin appears much reduced in 
volume and lies massed in a hall against one side of the nu¬ 
clear membrane. From this apparently synaptic mass thin 
chromatin strands again extend into the nuclear cavity.. 
Finally there appears a well developed spirem plainly oriented 
on the central body (Fig. 6). In the uninucleated stage, it is 
only where the chromatin is pretty well washed out that the 
center appears as such. It is then a very dark, disc-shaped 
body pressed close against the nuclear membrane. 
The perithecium has now grown to its full size, and has as 
many cell layers as when fully ripe. The outer layer of cells 
begins to show a differentiation into an upper and an under 
region, which is due to a thickening of the walls on the upper 
surface while the cells on the under side remain thin-walled 
and contain normal protoplasm and nuclei. The cell lumen is 
diminished by the thickening of the walls and is .almost emp¬ 
ty of protoplasm, while even at this stage the walls contain 
a brown pigment and are hard and brittle. Neger (21) first 
pointed out this differentiation, and described the thin flexi¬ 
ble walls of the lower cells as caving in when the perithecium 
is dried out, and bulging out as the cells absorb moisture and 
become turgid. This alternate drying and swelling of the cells 
would loosen the perithecium from its mycelium. A second¬ 
ary mycelium, such as is found in Phyllactinia (13), springs 
also from these lower living cells, and intertwines with the 
original mycelium covering the leaf. 
The transition cells in the equatorial region, midway be¬ 
tween the upper and under halves of the outer layer of the per- 
itheeial wall, give rise by the extension of their cell walls to 
the appendages. These grow out in a circle about the middle 
of the perithecium and are directed upward from the leaf sur- , 
face. 
The primary nucleus of the ascus undergoes three successive 
divisions, giving rise to two, four, and finally to eight nuclei, 
all of which form spores. 
I find in an early prophase of the first division two centers 
about 90° apart, each with a large aster of long, fine rays, and 
a broad brush of fibers extending into the nucleus (Fig. 8)., 
