MADREPORA. 191 
206. Madrepora rayneri. (Plate VIII. fig. A.) 
Madrepora rayneri, Brook, Aun. Mag. N. H. 1892, vol. x. p. 461. 
Corallum forming horizontal fronds similar to those of M. speciosa, but less confluent 
and dense. Branches 1 to 1°5 em. diameter, scarcely flattened; under surface naked, 
excepting for a few scattered and appressed twigs ] em. or more in length, which consist 
usually of an axial corallite with dilated base, with or without buds. The upper surface of 
the main branches bears scattered appressed, nariform corallites, with a few immersed ones 
interspersed. The branchlets on the upper surface are erect or suberect, and vary In im- 
portance from elongate and simple corallites to stout branchlets divided near the base into a 
number of heads, each of which bears several radiating and elongate corallites. The branchlets 
are usually 2 em. long, less near the margin and a little more near the proximal ends of the 
branches, the thickness varies from 3°5 to 7 mm. ; the stouter ones, like the main divisions, 
have appressed nariform corallites near the base. Elongate tubular corallites 1 to 1°6 em, or 
more in length, only slightly tapering ; 2°5 mm. diameter at the base and usually 2 mm. at 
the apex ; margin suddenly contracted ; aperture small. The star consists of 6 well-developed 
septa; but in the immersed corallites there are 12 septa and one of the directives is usually 
stouter than the others. Corallum dense ; surface very finely and closely echinulate. 
The species differs from M. speciosa, which is probably its closest ally, in the less 
tapering tubular corallites with a suddenly contracted apex, and in the less flattened and 
confluent main divisions. 
Pacific Ocean : Fiji. 
a-c. Fiji Islands. F. M. Rayner, Esq. [P.]. 62. 2. 4. 30, 42 & 44. (Types.) 
207. Madrepora speciosa. 
Madrepora speciosa, Quelch, ‘ Challenger’ Reef Corals, p. 163, pl. x. fig. 1. 
Corallum shortly pedicellate, spreading horizontally, or slightly concave above ; consisting 
of much-divided and compressed branches, 9 to 10 mm. wide and 4 to 5 mm. thick, which 
are coalescent so as to form a thin broad plate with numerous meshes. The under surface, 
where the flattened coalescent branches are seen to form an irregular trellis-work, is almost 
destitute of corallites : there are a few small immersed ones, chiefly in the line of the fusions, 
and the branches bear sublaterally a number of twigs, consisting of an elongate tapering 
tubular corallite with lateral buds, similar to those of M. rambleri. The upper surface of 
the trellis-work is rendered quite irregular by the outgrowth of numerous elongate, tapering, 
tubular corallites, singly or in spreading clusters, the general direction being at right angles 
to the branches ; some are forked or trifid, others are divided into irregular clusters. They 
are about 1°5 em. long, 3°5 mm. diameter at the base when simple, 6 mm. or more when much 
divided, 1 mm. or in some cases a little over at the apex; they are thus markedly tapering, 
2c2 
