MADREPORA. 105 
Corallum corymbose, short and stout pedicellate, flattened above. The branches on the 
under surface extend obliquely and are more or less fused together into a solid plate without 
twigs ; but where a space occurs between adjoining branches the margin bears stout spreading 
tubular corallites, and immersed corallites are scattered quite irregularly over the under 
surface. In other cases where the under surface is not so solid the prominent corallites are 
much more numerous, and some are proliferous and form short twigs in the general plane. 
On the upper surface the branchlets are crowded, short and tapering, simple or collected into 
groups of 2 to 5, frequently proliferous at the apex ; about 1:5 to 3 cm. long and 6 to 8 mm. 
thick at the base, frequently angular in the basal part. Axial corallites cylindrical, 1°5 mm. 
diameter, 1 to 2 mm. exsert ; wall thin, porous and strongly striate. Radial corallites crowded, 
ascending, open labellate, with rounded apex, a little unequal owing to incipient proliferous 
corallites; 2to 3 mm. long, 1 to 1°5 mm. thick ; wall very fragile, striato-reticulate. Star 
not distinct, even the directive septa not always recognizable. Corallum very porous; surface 
of branchlets strongly echinulate, denser and more finely echinulate on the under surface. 
Usually at a point about 1 cm. from the apex of a branchlet the corallites become shorter 
and finally immersed, but the aperture is alwaysabout 1mm. The corallites are slightly more 
spreading near the margin of the colony, but the angle rarely exceeds 45°. 
In Dana’s figure 4a the elongate lip of the corallites is not shown. 
The specimens in the Saville-Kent Collection differ from the Tahiti specimens in habit, 
but the corallites are of the same form. The habit is usually more prostrate and half- 
vasiform, without prominent tubular corallites on the under surface, but, on the other hand, 
one or two show the erect tubular corallites very well indeed. 
Indo-Pacific Ocean: Tahiti, Fiji, Great-Barrier Reef, East Indies, Mergui Archipelago, 
? Ceylon. 
a-c. Tahiti. H.M.S. ‘Challenger.’ 85. 2.1. 8 & 9, 92. 10.16. 9, 
d. Low Woody Island. Saville-Kent Coll. 92. 6. 8. 157. 
e. Capricorn Island. Saville-Kent Coll. 92. 6. 8. 160. 
fH. Rocky Island. Saville-Kent Coll. 92. 6. 8. 153, 158, 159 & 162. 
?7. Ramesvaram. Madras Museum. 93. 4. 7. 129. 
k. ? Purchased. 45. 9. 24. 5. 
98. Madrepora macrostoma. (Plate XIX. fig. B.) 
Madrepora macrostoma, Brook, Ann. Mag. N. H. 1891, vol. viii. p. 464. 
Corallum subcorymbose or umbellate, 33 em. broad and 15 em. high, consisting of 
crowded erect branches springing from an obconical fastigiate cluster of dead coral. Branches 
4.cm. long, simple or consisting of two or three subparallel divisions about 1 cm. thick, 
scarcely tapering. Apices a little over 1 cm. apart, the marginal ones very proliferous and 
sometimes acervate. Axial corallites 2°5 to 8 mm. thick and 1 mm. exsert. Radial corallites 
broad, round and ascending tubo-labellate, 3 mm. long, and 2 to 2°5 mm. diameter; aperture 
large and circular, wall very thin. Star well-developed but deep, consisting of twelve 
