88 MADKEPOEAEIA. 



appressed branchlets about 1 cm. thick and from 1 to 2'5 cm. 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 1'5 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. efflorescens 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 ascen cling tubular. 

 14. Madrepora acuminata. 

 Madrepora acuminata, Verrill, Bull. Mus. Comp. Zool. vol. i. 18G4, p. 40. 



The following is VerrilFs 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." 



