ON THE DEVELOPMENT OF LICHENOPORA VERRUCARIA. 141 
yet completely formed. The proximal edge of the basal lamina has nearly 
reached the disc. (Diameter, 1:18 mm.) 
Fic. 6.—Thick radial section of part of an old colony, showing the relations 
of the ovicell to the zocecia. (Diameter of the right-hand zoccium, outside 
the ovicell, = ‘192 mm.) 
Fie. 7.—A fully developed discoidal colony (diameter 1°92 mm.). The ovi- 
cell is obviously composed of a number of alveoli. The colony is probably 
left-handed, with occluded z?, some indication of which can probably be seen 
just beneath the single aperture of the ovicell. The zocecium to the left of 
the latter and above it is probably z?. 
Fic. 8.—Two zoecia from a very old colony, with secondary thickening. 
The porous roof of the ovicell is seen at the bottom of a set of honeycomb- 
like spaces, the so-called “ cancelli;”? some of these are covering the bases of 
the zocecia, and in the left-hand zocecium these are entirely or partially roofed. 
Two of the blister-like swellings thus formed have part of their roof still 
uncalcified. (Diameter of zoccia ‘14 mm.) 
Fig. 9.—From another old colony. The alveoli are still distinctly visible, 
and the cancelli are commencing in the interalveolar grooves, or at the base 
of the zocecia. The left-hand zocecium is closed by a porous calcareous cap. 
(Diameter of zocecia ‘13 mm.) 
PLATE 8. 
(N.B.—The measurements given below [except for figs. 12, 13] were made 
from the sections.) 
Fic. 10.—Part of a longitudinal section through the fertile zocecium (? z3) 
of a colony, ‘67 mm. in length, with about nine fully-formed zoccia. The 
elongated structure to the right of the fertile brown body is the embryophore. 
Fic. 11.—Section (diameter ‘80 mm.) of a colony with fully formed ovicell. 
The section is parallel to the flat surface of the plano-convex colony, and cuts 
the convex side near its upper surface (cf. fig. 6). The only zocecia seen in 
the section are thus the more centrally placed ones. z? was presumably the 
fertile zocecium, as it is empty basally, and contains secondary embryos, at its 
upper end. The fertile brown body has passed into the ovicell. z? also con- 
tains secondary embryos, but has a brown body basally, and was probably 
occluded without being fertile. The secondary embryos are contained in the 
“ embryophore,”’ whose lobes extend, in the cavity of the ovicell, between the 
zocecia. The zocecium A contained a brown body lower down. 
Fig. 12.—Entire colony (diameter 1°41 mm.), stained and mounted in 
Canada balsam. The shaded part shows how much of the ovicell is com- 
pletely roofed. The alveoli which are still unroofed are not specially indicated. 
The ovicell has an aperture, at the base of which is the fertile brown body. 
