go Magnus . — On some Species of 
cells which conjugate with female cells originating from other 
hyphae (Figs, io and 13). The hyphae often branch, especially 
from the male cells (Figs. 10 and 11). 
As Schroeter has already described in the case of Urophlyctis 
pulposa , the receptive and enlarging cell separates also, in the 
present instance, from the parent hypha. Therefore I have 
not been able to determine whether a single hypha produces 
several receptive or female cells. 
The female cell enlarges, becomes filled with dense proto- 
plasm containing oil-globules, and develops a thick brown 
cell-wall. On the side where conjugation with the male cell 
takes place it remains flat and depressed in the centre. The 
process of conjugation can be most clearly observed, as 
Schroeter has done in the case of U. pulposa ; and I believe 
that Fischer was led to his conclusions rather from descrip- 
tions, and the statements made by Biisgen as to the formation 
of resting-sporangia in Physoderma , than from actual personal 
investigation of the subject. 
From the structure of the gall, as described, it is most 
probable that the germs of the parasite enter an epidermal 
cell, which in consequence swells considerably and causes 
frequent divisions in the surrounding epidermal cells. The 
particular cell attacked by U. Kriegeriana becomes the 
central cavity of the gall, whilst the surrounding epidermal 
cells undergo repeated subdivision and form a wall around 
it consisting of several layers of cells, leaving at the apex 
a crater-like opening. 
As before stated, U. Kriegeriana grows only within the 
enlarged cavity of the gall, and never extends beyond it. 
The development of the wall of the central cell corresponds 
with this. The wall thickens considerably, almost attaining 
the width of the neighbouring cell-layer of the envelope of 
the gall. It never exhibits the sieve-like perforations or the 
grating-like appearance which De Bary and Schroeter have 
described in U. pulposa . The strong imperforate membrane 
is not traversed by the delicate hyphae of the Fungus, and 
the parasite remains confined to its enlarged host-cell. 
