REPORT ON CORALS—HYDROCORALLIN &. 51 
such branches. The branches and branchlets are nearly circular in section, and have a 
hirsute or finely spinous appearance. This appearance is due to their being beset all 
over their surfaces with small nariform projections, the wide openings of which are all 
turned towards the tips of the branches. These nariform projections vary much in form, 
being often drawn out into tubes opening by a slit-like mouth on the side next the tip of 
the branch, and frequently coalescing, especially towards the tips of the branches, so that 
two or three of the projections have a common base. 
These projections are the prolongations of the walls of the dactylopores beyond the 
main surface of the coonosteum. Their cavities, the pores, are simply tubular without any 
style, and extend for a short distance into the mass of the branch, on which they are 
situate in an oblique direction, in continuance of the oblique inclination of the nariform 
projections. The dactylopore projections are very numerous and closely set towards the 
tips of the branchlets, more widely scattered upon the surfaces of the branches and 
almost absent on the main stems. 
Scattered over the surfaces of the branches and branchlets are the mouths of the 
gastropores, which are tubular cavities larger than the dactylopores, but with a similar 
oblique direction towards the axes of the branches, and are provided with a calcareous 
style, with a finely dentate surface (Pl. IV. ST). The mouths of the gastropores are 
uregularly circular in outline, their margins being frequently broken and indented 
by the confluence with the pore cavities of the superficial channels of the surface 
of the ccenosteum. The gastropores are frequently situate beneath the bases of the 
dactylopore projections, so as to be covered by these as by a projecting lp; and 
in places the margins of the gastropores themselves are drawn out into scale-like lips, 
though these lips are nearly always fused: with nariform projections of contiguous 
dactylopores. Gastropores are frequently to be seen occurring isolated and solitary on 
the branches. 
The ampullz are, in this genus, conspicuous bodies, since they appear as hemi- 
spherical projections from the surfaces of the branches of about the size of a mustard- 
seed. In vigorous specimens they are closely crowded together in masses on both sides 
of the branches and branchlets in various regions of the flabellum. The ampulle 
commence as small cavities in the surface layer of the ccenosteum of the branches, and 
gradually enlarging in accordance with the development of the ovum contained in each, 
project more and more, until those containing mature, or nearly mature, planule 
appear as the conspicuous projections above described. A hemispherical cavity, 
excavated in the surface of the ccenosteum, corresponds with each ripe ampulla, but the 
excavation is usually not deep enough to render the entire ampullar cavity spherical 
in form. The cavity has rather the form of a sphere with one side somewhat flattened. 
In accordance with the gradual expansion of the ampullar cavity, its outer wall, which 
is finely reticular in structure, becomes thinner and thinner until, no doubt, it at last 
