MADREPOEA. 191 



206. Madrepora rayneri. (Plate VIII. fig. A.) 

 Madrepora rayneri. Brook, Ann. Mag. N. H. 1892, vol. x. p. 461. 



Corallum forming horizontal fronds similar to those of M. speciosa, hut less confluent 

 and dense. Branches 1 to 1-5 cm. diameter, scarcely flattened; under surface naked, 

 excepting for a few scattered and appressed twigs ] cm. 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 hears 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 cm. long, less near the margin and a little more near the proxipial 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 cm. 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. Uadrepora speciosa. 



Madrepora speciosa, Quelch, ' Challenger ' Reef Corals, p. 163, pi. 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. ramhleri. 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 cm. 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 



