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 em. 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 em. 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 
2mm. 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 em. 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 em. 
in the type specimen, in the one under consideration it is only 35 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 Jarge (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.) 
b. 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 8 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 
