ON THE DEVELOPMENT OF LICHENOPORA VERRUCARIA. 128 
by strands of nucleated protoplasm, which thus divides the 
space into smaller cavities in which the derivatives of the 
primary embryo lie. 
I believe that the processes which take place at this stage 
are practically like those which occur in Crisia. The whole 
mass of the embryophore becomes highly vacuolated, and is 
thereby transformed into a series of more or less definite spaces 
in which the secondary embryos will lie. These spaces become 
more definite near the aperture of the ovicell. In the next 
stage I have often observed mature embryos in the tubular 
aperture, obviously on their way out to the exterior. 
Very few of the colonies which I have observed in this stage 
have a smaller transverse diameter (in sections) than ‘60 mm. 
The extreme measurements I have noted are ‘45 mm. and 
1:04 mm. The average of the measurements of the transverse 
diameter of twenty-four colonies in this stage is ‘747 mm. 
There is great probability that Stage F corresponds with a 
condition of the entire colony in which the fertile zocecium is 
occluded, and the very beginning of the formation of the roof 
of the ovicell is taking place. 
Stage G.—Ovicell well developed. 
The Production of the First Brood of Secondary 
Embryos is at its Height. 
Fig. 11, which shows a characteristic horizontal section of 
a colony in this stage, has already been described (p. 94). 
The fertile brown body still remains compact and conspicuous ; 
and it occurs in the immediate neighbourhood of the trumpet- 
shaped aperture of the ovicell. During this stage it is, how- 
ever, no longer found in the fertile zocecium, which in the 
section drawn (fig. 11, z?) is seen to contain some secondary 
embryos at its upper end. ‘The cavity of this zoccium has 
become continuous with that of the ovicell in the manner pre- 
viously described (p. 87), and the brown body has passed out 
into the cavity of the ovicell proper. The brown body still 
forms a kind of centre from which the lobes of the embryo- 
