At this period of growth it is necessary to consider a
series of buds on the periphery of the corallum, marked 1”,
2", etc., in Plate XXXII, figures 8 and 4. They are first
triangular in form like the others, and of two sizes, owing to
their different ages. The growth of this series continues
until they touch and truncate the angles of the first series
(1', 2', etc.), producing the fifth condition or stage. The
first series of buds has now three hexagonal and three
pentagonal corallites (Plate XXXII, figure 5).
In the last or sixth stage (figure 6), the further growth of
all the intermural cells results in a corallum of nineteen nearly
equal hexagonal corallites. The original parent cell (A) is
at the centre, the first six intermural cells (1’, 2', etc.) com-
pletely surround it, and the six new peripheral corallites
(Z", 2", etc.) are interposed between the members of the
original circlet (J, 2, ete.). The effect of this intermural
growth, then, is to dissociate all the first series of corallites
from the parent cell and from each other. (See Plate
XXXITI.)

The changes taking place in the number and form of the
cells may be tabulated as on page 433.
