4i 6 Osterhout. — On the Life- His lory of 
Many of the terminal cells of the gonimoblastic filaments 
which radiate from the carpogenic cell, instead of changing into 
spores, grow out into sterile filaments, often branching dicho- 
tomously, and composed of a few elongated cells (Fig. i, 
x, x, x, Sic.) These reach the pericarp and attach themselves 
to it, forming connexions by means of secondary pits with the 
cells of its innermost layer. 
Development of the Pericarp. 
The sterile cells of the branch containing the auxiliary cell 
give off branching filaments of cells, and perhaps a few such 
filaments occasionally proceed from the auxiliary cell ; these 
divide very irregularly, not following the rule for the division 
of ordinary vegetative cells, and by the time that conjugation 
with the auxiliary cell takes place, they form a pericarp 
investing on all sides the auxiliary cell and its four large 
accompanying cells, already mentioned (Figs. 2, 3, 4, and 5). 
In that portion of the pericarp lying towards the interior of 
the frond the divisions take place in such a way that numerous 
rows of cells are formed, radiating from the centre of the mass, 
which is occupied by the auxiliary cell and its accompanying 
cells (Fig. 4). Nearest the centre of the mass the cells of each 
filament are small, and there is a regular increase in the size 
of the cells going towards the periphery ; this is accompanied 
by an elongation of the cells in the tangential direction. In 
the case of the outermost ones this elongation is so great that 
they come to resemble the elongated cells of the medulla of 
the frond (Figs. 4 and 1). The portion of the pericarp lying 
outside the auxiliary cell forms the cortex of the frond at that 
point (Figs. 2-5). It is composed of branching filaments like 
the ordinary cortex, but the cells are from the first more 
densely filled with granular protoplasm. These cells begin, 
shortly after conjugation with the auxiliary cell takes place, 
to grow and divide rapidly, forming a mass which, as com- 
pared with the ordinary cortex, is much thicker and composed 
of smaller cells. The entire pericarp thus develops almost 
