414 OsterZiout — On the Life-History of 
tube bends outwards and makes its way through the cortex to 
the auxiliary cell. As the conjugating-tube develops, the 
trichogyne is displaced to one side and gradually becomes 
disorganized, the disorganization proceeding from the tip 
towards the point of attachment (Fig. 13 tr). 
Origin of the Auxiliary Cells. 
Certain lateral branches of the cortex begin very early to 
have a different appearance from the ordinary branches which 
surround them on all sides. Their cells become more densely 
filled with granular protoplasm, and in many of them the 
chromatophore becomes paler. The basal cell of every such 
branch rests on one of the elongated cells of the medulla, 
is usually much elongated and has less protoplasmic contents 
than the other cells of the branch (Fig. 2, a). The next 
cell is larger (Fig. 2, st ) and has fairly dense contents, and 
frequently bears one or more lateral branches. The next cell 
of the branch is commonly somewhat constricted in the middle ; 
this third cell in the branch is the auxiliary cell (Fig. 2, cpg) 
with which the conjugating-tube later unites. The auxiliary 
cell always bears three large cells, one at the top (Fig. 2, 6 ), 
and two just below it on the outer side (Fig. 2, c and d). The 
auxiliary cell, together with the three cells which are borne on 
it, and the cell upon which it rests, form a group of five large 
cells, which possess colourless chromatophores, and are densely 
filled with granular protoplasm. Each of the three cells 
borne upon the auxiliary cell gives rise to several branches 
which branch more or less freely, and form a mass of small 
cells lying externally to and around the auxiliary cell (Figs. 3, 
4, 5 and 1). 
These possess for the most part well-developed chroma- 
tophores, which are deeply coloured as those of other cortical 
cells of the same size which are borne on purely vegetative 
branches, but the first-mentioned cells are distinguished from 
the last-mentioned by their position and by their richer 
protoplasmic contents. 
