MADREPORA. 101 
the branchlets of the upper surface, and the occurrence of numerous spreading tubular 
corallites on the under surface. There are several specimens in the collection of the British 
Museum which agree with Dana’s figure in these respects, and at first sight there appears 
little affinity to specimens of M. cytherea from Tahiti, the original habitat. The colony is 
umbellate rather than vasiform, and is flat on the upper surface excepting in very small 
colonies where the central branches are not so long as the others. That it is not the 
ordinary young form of M. cytherea appears to be shown by the fact that in specimens of 
25 cm. diameter scarcely any proliferous corallites occur, whereas in the normal specimen 
of M. cytherea, of 30 cm. diameter, proliferous corallites are numerous and the corallites of 
the under surface are dilated verruciform. It appears, therefore, more convenient to regard 
it as distinct. 
Corallum vasiform or umbellate, pedicellate, flat above excepting when young, under sur- 
face oblique. Height of the corallum 15 cm., diameter 25 cm.; diameter of pedicel 6 to 
8 cm. The outer branches are about 1:2 cm. thick and 9 to 12 cm. long, crowded and a little 
compressed laterally. On the outer or under surface they bear numerous spreading, tubular, 
often proliferous, corallites, 15 to 2 mm. diameter and 2 to 4 mm. long if simple, but the 
majority are in some specimens more elongate and bear buds. On the pedicel these corallites 
form short tapering branchlets spreading at right angles and often 1 cm. in length. The 
interval between these twigs and proliferous corallites is occupied by short-lipped or immersed 
ones. The branchlets on the upper surface are usually arranged in groups of 2 to 6 from a 
common base ; those in the centre are longest, and the apices are about 8 mm. apart; length 
1:5 to 4 em., diameter 6 mm. or a little over, apices rarely proliferous unless near the 
margin of the colony. Axial corallites 2 mm. diameter, 1 to 2 mm. exsert, cylindrical, with 
porous and strongly striate wall. Radial corallites spreading tubo-labellate or gutter-shaped, 
with very thin fragile and reticulate wall; length 2 to 3 mm., diameter 1 to 15 mm., 
becoming shorter and finally immersed below. The corallites are not so spreading on the 
marginal branchlets as nearer the centre. Star scarcely at all developed, usually only the 
directive septa are recognizable. Corallum very porous; surface striato-echinulate ; wall 
striato-reticulate, echinulate near the base. 
Indo-Pacific Ocean: Singapore, Diego Garcia, ? Tahiti. 
a. Singapore ? W. E. Hands, Esq. [P.]. 50. 1. 16.1. 
6. Singapore. T. Ingall, Esq. [P.]. 57. 4. 6. 1. {nye 
c, d. Diego Garcia. G. C. Bourne, Esq. [C.]. 91. 4.9.6 & 7. 
?e. Tahiti. H.M.S. ‘Challenger.’ 86. 12. 9. 410. 
(=M. cytherea, Quelch, part.) 
jf. —? Purchased. 40. 5. 29. 1. 
g- —? ? 93.4. 7. 164. 
h. ——? 2? 49.5. 15. 11. 
i-k, ——? ? 93. 4, 7. 124, 125 & 131. 
