99 
as the genera Forties , Astreopora^ and Alveopora , room xi. 
the centre of the cells, instead of being lamellar, 
are filled with close-set tubercles, and the in¬ 
terstices between the cells are porous. In the 
Deer’s-horn coral (Falmipora ) the cells are very 
minute, shallow, and scarcely striated on the 
sides. In the Bcecillopora and Heliopora they 
are larger, with raised dentated edges, but 
shallow, and sunk into a very hard solid coral: 
from these last the Seriatopores only differ in 
the pores being placed in longitudinal lines. 
The genus Distichopora is allied to these in 
some characters, but its cells are simpler and 
placed in three series on each side of the coral, 
those of the two lateral series being much 
smaller than the central one. 
The cells in the rest of these corals are fur¬ 
nished with regular and distinct rays, like those 
of the first group. In a few of these, as the White 
Coral ( Ocutina ), the coral is subcylindrical 
and arborescent, and in others, as the Star-stones 
(.Astrece ), the coral forms a globular, or ex¬ 
panded, encrusted mass. 
In some of the Star-stones the axes of the cells 
are solid and produced, as in the Astrea Pleiades , 
so as to resemble in that respect the fossil 
genera Sarcinula , and Stylina , peculiar for the 
centre of their stars being produced. The 
Explanarice only differ from the star-stones in 
the mass being more expanded and foliaceous, 
h 9 , 
or 
