ORDER ACTINOIDEA. 69 
The Caryophyllie* afford still other examples of segregate zoo- 
phytes, with convex forms, arising from the budding function being 
received equally and retained indefinitely by each polyp. The mul- 
tiplication of lateral buds causes the ascending stems to diverge, 
and the clump becomes rounded above. Yet the outer portions of the 
clump, owing perhaps to their receiving first the waters around, often 
extend a little the most rapidly, and the form becomes thus flattened 
convex, rather than regularly hemispherical. The spaces between 
the branches are quite uniform in the same species, as well as the 
length of interval between successive buds from the same branch. 
70. A budding cluster. But when with an acrogenous mode of 
growth, the polyps, after a certain age, lose the function of budding, 
the zoophyte, commencing as a small hemisphere, lengthens upward 
into a cylinder, whose diameter is determined by the breadth of the 
budding cluster. This cluster constitutes the extremity of the stem 
or branch, and, as it is constantly forming new buds, the older polyps 
of the cluster, at the same rate, are turned out, and joined to the 
lateral non-budding polyps of the branch. By this process, the branch 
continues to elongate. The Porites, Sideropore, and Pocillopore, 
afford examples. 
Stems produced from a budding cluster have generally rounded or 
flattened summits. Exceptions to this are found in some Seriato- 
pore. In these species, the budding cluster is quite small, contain- 
ing but six or eight polyps; the three or four alternate push out buds 
nearly simultaneously at the very apex, and then the others, another 
set beyond these, each set constituting successively the apex, which 
is consequently pointed. In some Gorgonie, also, in which the 
budding cluster is very small, the stems are pointed. 
71. Budding from an apical or parent-polyp. Instead of a budding 
cluster, the Madrepores and Dendrophyllie have a single budding or 
parent-polyp at the apex of each branch, from the sides of which the 
lateral buds are given out. 
This is shown in the following figure of a Dendrophyllia. The 
terminal polyp is the parent from which all the polyps of the branch 
have proceeded. 
Hach branch of a Madrepora, in the same manner, has its parent- 
polyp. In these genera, the branches have a conical or tapering 
extremity, while in those which grow and bud from a cluster, 
* The Cladocoree of Ehrenberg. 
18 
