MADREPORA. 183 



8 cm. or under in length and 1 cm. or more thick, not flattened. The under surface bears a 

 number of spike-like, little-divided branchlets, about 2 cm. long, spreading almost at right 

 angles ; the corallites on the under surface of the branches are immersed, aperture about 



1 mm. The upper surface bears numerous stout suberect branchlets, most of which are 

 much and spreadingly divided, 2 to 4 cm. long and 5 to 7 mm. thick. The majority of the 

 corallites on these branchlets and also on the upper surface of the branches are thick 

 appressed tubular or hemicotyloid ; sometimes the outer part of the wall is produced into 

 a blunt point; they are 2 mm. diameter and 2 to 4 mm. long, margin usually thick and 

 rounded. Axial corallites tubular, 6 mm. or more in length, 2*5 to 3 mm. thick, tapering to 



2 mm. In addition to the axial corallite, two or three near the apex become elongate 

 tubular, very spreading, and bear buds. The star consists of 12 well-developed septa. 

 Corallum very dense ; surface and wall finely echinulate. The specimen is a triangular 

 fragment 12 cm. long and 13"5 cm. broad; the apices of nearly all the branchlets are much 

 broken and the surface is worn. 



Another specimen in the Collection, from Malacca, is probably referable to this species, 

 although at first sight it differs considerably. It is, however, a much more perfect specimen, 

 a factor which accounts for much of the apparent difference between the two. The 

 stoutest branch is 1'2 cm. thick, and becomes subdivided as in the type, the divisions being 5 

 to 20 mm. apart, with only one instance of fusion between adjoining branches. The chief 

 variation from the type occurs on the under surface. . The branches here are a little flattened 

 and the spike-like branchlets, instead of standing out nearly at right angles, are pressed 

 almost into the plane of the branches as in M. speciosa and M. rambleri. This has the 

 effect of considerably reducing the thickness of the corallum ; this thickness is about 5-5 cm. 

 in the type specimen, in the one under consideration it is only 3-5 to 4 cm. On the upper 

 surface of the branches the appressed tubular corallites are more clearly defined, have usually 

 a thinner wall, and the aperture is large (1 mm.). The distal extremity of each branchlet 

 consists of from two to five radiating and elongate tubular corallites, 7 to 12 mm. long, 



3 mm. diameter or over at the base, and rather under 2 mm. at the apex, wall thick, margin 

 rounded, aperture one third of the diameter or less. The tubular corallites bear nariform bud- 

 corallites to within 3 or 4 mm. of the apex. Septa in two cycles, both of which are 

 narrow. 



Indo-Pacific Ocean : Fiji, Malacca. 



a. 



Kandavu, Fiji, H.M.S. 'Challenger.' 86.12.9.244. (Type.) 



J.Malacca. Sir E. Belcher [P.]. 42.11.28.8. (Var.) 



197. Madrepora clavigera. (Plate IX. figs. A, A'.) 



Madrepora clavigera. Brook, Ann. Mag. N. H. 1892, vol. x. p. 455. 



Corallum forming horizontal fronds 3 cm. thick, the main divisions of which are 

 reticulately coalescent. Branches sinuous, flattened below, about 1 cm. broad. Corallites 

 on the under surface chiefly marginal, stout tubular, with a rounded apex, rather spreading, 



2b2 



