ON THE DEVELOPMENT OF LICHENOPORA VERRUCARIA. 95 
the ovicell (not seen in the section figured). There is no 
aperture in connection with z’, or indeed with any of the other 
zocecia. The colony has every appearance of being perfectly 
healthy. The sections of its basal part show that nearly 
every zoecium has a functional polypide. Only one of these 
polypides has any trace of a testis, which consists of a small 
mass of degenerating spermatozoa. 
The occurrence of an ordinary brown body in z’? makes it 
improbable, as will be shown later, that this was the fertile 
zocecilum ; and it is in the highest degree probable that the 
primary embryo of this colony was produced by 2%. This is 
indicated by the position of the apertnre of the ovicell and by 
that of the fertile brown body, as well as by the occurrence of 
embryos within the cavity of z2. The connexion between z°® 
and the ovicell probably implies that z*? had been occluded 
(cf. p. 89). 
My preparations include a practically continuous set of stages 
- between fig. 11 and the commencement of the development ; 
and my results are based on the examination of complete 
series of sections through some three hundred colonies, in 
eighty-nine of which no embryos can be detected, while in 
seven more, degeneration had set in after the commencement 
of the development. The large number of fertile colonies 
examined enables me, to a large extent, to eliminate abnorma- 
lities in the development. 
An examination of the cases in which normal embryonic 
development was not found will give some useful information. 
The negative result in at least twenty cases was probably due 
to the fact that the colonies were too young. A careful com- 
parison of my measurements of entire colonies and of sections 
shows that the commencement of the embryonic development 
is to be looked for in colonies which measure about *40— 
‘43 mm. in total length, and about ‘25 mm. in transverse 
diameter, i.e. in colonies which are at about the stage of 
fig. 2. 
In the next place I am able to confirm the suggestion I 
formerly made (6, p. 212) to the effect that the normal develop- 
