96 THE VOYAGE OF H.M.S. CHALLENGER. 



branches to a uniform height. All inclined in the directions of the tips of the branches. 

 The elongate cavities, which are extended in the direction of the lengths of the branches, 

 have a defined rounded margin at their ends, situated towards the tips of the branches, 

 but gradually merge at their opposite extremities into the deep and complex hollows by 

 which the surface of the coral is excavated, and which are made up of the confluences 

 of cavities of adjacent nariform projections with the other irregularities of the surface. 

 Dactylopores devoid of styles ; two kinds present, larger and smaller. The nariform 

 projections are the outgrown margins of the larger dactylopores, which are continued 

 into the substance of the coenosteum from the cavities of the projections as tubular slits. 

 The smaller dactylopores have mouths of the same general form as those of the larger 

 ones, but with their longer diameters directed at right angles to these latter. They 

 have their walls fused with those of the nariform projections, or often appear as if 

 excavated in the sides of these. They are of one-third or one-fourth the dimensions 

 of the larger pores. Mouths of the gastropores deeply seated in depressions at the 

 bases of the nariform projections. Circular in outline. Gastropores provided with 

 deeply-seated styles with brush-like tips. No ampullse in the unique specimen. Soft 

 structures unknown. 



6. Spinipora, Moseley. 1 



Coenosteum branching. Branches rounded. Entire surface thickly beset with long 

 spinous projections inclined towards the tips of the branches. Spines conical, grooved 

 deeply on their sides turned towards the tips of the branches, so as to present spout-like 

 openings, which are the mouths of the larger dactylopores. Dactylo]3ores of a smaller 

 kind also present ; their mouths appear as minute oval apertures scattered over the 

 bases and sides of the spines. Styles absent in the dactylopores. Gastropores deeply 

 seated in hollows between the bases of the spines, having deeply placed styles. Ampulla? 

 absent in the unique specimen. Dactylozooids of two kinds, the larger attached by 

 elongate bases within the spout-like cavities of the larger dactylopores, incapable of 

 retraction within the pores ; the smaller minute, entirely retracted when at rest. 

 Gastrozooids cylindrical, with six tentacles and four basal canals. Gonophores unknown. 



7. AUopora, Ehrenberg. 



Coenosteum branching, but frequently not so as to form a flabellum. Pores in 

 regular cyclo-systems only, excepting in AUopora nobilis, where some of the systems 

 are not perfected. Tendency to alternate gemmation present, but weak, and usually 

 obscured by an abundant growth of eoenenchym. Cyclo-systems always scattered 

 over the faces of the branches, as well as situate at their lateral margins ; often 

 entirely sporadic in disposition. Dactylopores with a more or less rudimentary style 



1 Prelim. Report, Phil. Trans. Roy. Soc, 1878, part 2, p. 476. 



