REPORT ON CORALS — HYDROCORALLIN.E. 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 ccenosteum. 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 oblicpie 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 

 oblicpie direction towards the axes of the branches, and are provided with a calcareous 

 style, with a finely dentate surface (PI. IV. S T). The mouths of the gastropores are 

 irregularly circular in outline, their margins being frecpiently 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 lip ; 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 ampullse 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 ampullse 

 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, planulae 

 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 



