ORDER ACTINOIDEA. 77 
limits that belongs to the adult animals. In the corallum, it may 
be seen to begin by the union of two opposite calcareous lamelle, 
and the gradual formation of other lamellw, each side of the united 
pair, in completion of the circle in each cell. 
Fig. 35. 
This process resembles somewhat the spontaneous fission of the 
monad, and is compared to it by Ehrenberg. From the illustrations 
given, it appears to be altogether analogous to budding exterior 
to the disks, and differs only in the position of the point from 
which budding commences. ‘This subdivision, though sometimes 
apparently central, yet often separates only a small portion of the 
parent; and, instead of being a fission of an individual, it results by 
a slow divergent growth of the parent and bud. In the Meandrine, 
Meruline, and others, the disk-buds open successively in long series, 
mithout any proper subdivision of the polyps. Moreover, the Astrea 
stellulata, A. stelligera, and A. intersepta, bud exterior to the disks, and 
sometimes also within the disks. The Meruline occasionally exhibit 
a few cells very similar to those of the Echinopore, thus bringing 
together these two divisions in the Astrea family. 
c. In the Monticularie, the elongating lines of disks are united by 
cross-lines, so that the whole surface appears like a single reticulate 
disk, with numerous polyp-mouths distributed over it, and having 
small scattered conical prominences, around which the tentacles are 
clustered. ‘These species are thus closely related to the Meandrina, 
and the prominences are the remains of the ridges (plate 13, fig. 13). 
78. Relation of the Fungide to the Astreaide. In the Astreide, the 
lamell of the cells, which striate the interstices in massive species, 
are generally interrupted half-way between adjoining cells, as in fig. 
34: in other words, each polyp has its limits distinctly marked in the 
corallum. But in the Fungide, which are closely allied species, 
there are no cells, and the lamelle are continuous from centre to 
centre. We are aided in understanding the relation of the two 
families, by observing that in some Meandrine species, there are 
along the bottom of the trench, one to three narrow lamelle, running 
20 
