38 MADREPORARIA. 
appressed branchlets about 1 cm. thick and from 1 to 2°5 em. long; surface spongy, with 
scattered immersed corallites and a variable number of dilated appressed tubular ones about 
3 mm. thick, narrowed towards the apex; star of 12 well-developed septa, wall striato- 
echinulate. On the upper surface all but the central portion consists of several layers of 
radiating subhorizontal branches laid one over the other like rows of tiles, the lower layer 
longest, and the others gradually diminishing in length, the whole fused into a solid mass 
with often only the distal parts of the branches distinct; diameter of the branches 8 to 
20 mm. Axial corallites cylindrical, variable in size, 2°5 to 4 mm. diameter, and 2 mm. 
exsert, wall thick and porous, strongly striate, aperture 0°75 mm. The branches bear 
numerous prominent corallites, 2°5 to 6 mm. long, and 15 to 2 mm. thick, the larger of 
which are proliferous, but the buds which they bear are always small and delicate labellate. 
The prominent corallites are dimidiate and a little appressed near the apex of a branch, but 
in other situations generally spread almost at right angles. Those which become proliferous 
are 2 to 3 mm. apart, and in them the inner part of the wall gradually increases in length, 
at the same time the wall is thickened, and they then resemble the smaller axial corallites in 
form. Between are small labellate corallites with a narrow lip and numerous small immersed 
ones. Star well developed in nearly all the prominent corallites, the directive septa very 
broad. In the very numerous and small immersed or narrow-lipped corallites the directive 
septa are often confluent, but the other primary septa are relatively narrow. Corallum very 
porous, surface spongy-reticulate, wall striato-reticulate and echinulate. 
The species resembles M. effiorescens in general habit, but differs altogether in its disk- 
shaped corallum, composed of several rows of branches instead of a single row, in the 
scattered instead of clustered proliferous corallites, in the stouter axial corallites, the much 
smaller bud-corallites of the proliferations, the condition of the under surface, and in 
other points. 
Indian Ocean : Ceylon. 
a, Ceylon. Dr. Ondaatje [P.]. 83. 3. 24. 7. (Type.) 
b, c. Ceylon. Haeckel Coll. 92. 12. 5. 25 & 26. 
C. Prominent radial corallites ascending tubular. 
14, Madrepora acuminata. 
Madrepora acuminata, Verrill, Bull. Mus. Comp. Zool. vol. i. 1864, p. 40. 
The following is Verrill’s description :— 
« A large species allied to M. nobilis, but having much longer, regularly-tapering, often 
curved branches, 1 inch in diameter, evenly rounded, and thickly covered by spreading, nearly 
uniform, cylindrical, dimidiate corallites. Surface of the corallum between the cells and 
exterior to corallites covered with minute spines, the latter subcostate. Septa rudimentary, 
only the two largest usually distinct. A few rudimentary corallites, often opening downwards, 
are scattered among the others.” 
