SUBDIVISIONS OF ACTINOID POLYPS. ral 
phore; and the branches vary from the flattened and broad 
form shown in figure 7 (which represents the upper part of 
a branch of the P. grandis D.), to irregularly cylindrical 
branches, looking rough on account of the very short branch- 
lets. The cells are usually stellate, as in figure 8, from ge 
elongata D., and often one of the septa, and sometimes two 
opposite ones, extend to a columella at the centre, as illustra- 
ted in figure 9, from P. plicata D.; dividing the cell into 
halves. The cell in the interior of the corallum is crossed by 
thin plates or tables, as shown in figure 10, and hence they 
have been called tabulate corals. Agassiz, after the discovery 
of the Hydroid character of the animals of the Millepore corals, 
whose cells also are tabulate, referred the Pocillipore to the 
same Hydroid type. But the recent study of the polyps has 
shown that they are true polyps; and Prof. Verrill remarks 
on the resemblance of the tentacles to those of the Oculine. 
‘The stellate character of the calicle also proves that the ani- 
mals must be polyps. ; 
Madrepore tribe, or Mapreporacea.—In this tribe the cor- 
alla, even to the walls of the corallets, are remarkable for be- 
ing porous, and the radiating lamelle of the polyp-cells are 
narrow, often perforated or imperfectly developed, and fre- 
quently mere points. The coralla are either branched, mas- 
sive, or foliaceous. Budding is lateral, and in the branching 
species there is either a parent polyp, as in Madrepora and 
Dendrophyllia, or a terminal budding cluster. This peculiar- 
ity has been already illustrated in the figure of Madrepora 
aspera,on page 50. On the following page there is an out- 
line sketch of another species, the Madrepora formosa D., 
common in the Feejees, and also in the Kast Indies. The two 
species here mentioned give a good idea of the ordinary char- 
acter of the Madrepore corals. One of the polyps of the Mad. 
