MADREPOEA. 163 



2 to 5 proliferous corallites 2*5 mm. thick. Axial and proliferous corallites conical, 3 mm. at 

 the base, tapering to 1'5 or 2 mm. at the apex, 2 to 3 mm. exsert. Aperture of the corallites 

 generally round, that of the nariform and tubular corallites usually smaller than in the others. 

 A few axial and proliferous corallites have a alit-like aperture. Coenenchyma porous ; wall 

 finely echinulate, indistinctly striate. 



I am inclined to regard the specimens recorded by Ortmann as M. valida, M. secale, and 

 M. remota as varieties of this species, and, at any rate, all have many characters in common. 

 The form referred to M. valida is rather cespitose than corymbose, but still shows the 

 marginal branches more or less confluent. The specimens referred to M. secale have elongate 

 horizontal branches fused into a plate. The type of M. remota differs chiefly in its plate-like 

 habit, in having more distant branchlets, and near the centre of the colony a number of sub- 

 erect, elongate, tubular twigs occur, which may be 2 cm. long, 4 mm. broad at the base, and 

 2'5 mm. at the apex. If I am correct in regarding this form as a variety of M. ceylonica, 

 these elongate tubular twigs must be regarded as axial corallites on which lateral buds have 

 not become developed. 



Ceylon ; ? Macclesfield Bank. 



a, b. Ceylon. Haeckel Coll. 92. 12. 5. 17 & 31. 



c. 



Ceylon. Dr. Ondaatje [P.]. 83.4.26.3. 



rf'. Ceylon. Haeckel Coll. 92.12.5.21. (?iW 



Ortm.) 

 ?e. Macclesfield Bank, 18 to 28 fathoms. H.M.S, 'Penguin.' 92. 10. 17. 78 



173. Madrepora tumida. 



Madrepora tumida, Verrill, Coram. Essex Inst. 1866, vol. v. p. 21 ; ibid. 1870, vol. vi. p. 102.; Bathbon, 

 Proc. U.S. Nat. Mus. 1887, vol. x. p. 19. 



Corallum corymbose, the branches coalescing into a broad massive base, supported by 

 a thick peduncle, the upper surface flattened. Towards the margin the branches spread 

 horizontally, and gradually become loosely coalescent and free ; from the whole upper surface 

 arise numerous nearly upright branchlets, which are rather stout, about 5 cm. high, tapering 

 rapidly, and mostly divided into several small secondary branchlets. Radial corallites large, 

 thick, and turgid, somewhat appressed ; the cells large, opening upwards, conspicuously 

 stellate, with 12 septa, of which the secondary ones are much the narrowest; two directives 

 nearly reach the middle line. Axial corallites somewhat larger than the radial, exsert, the 

 margin thick, very porous ; primary septa equal, secondaries well developed. The cells at the 

 base of the branches are wholly immersed, but have 12 conspicuous septa. On the lower 

 surface there are very few cells ; these are very small and wholly immersed. Surface of the 

 coenenchyma openly reticulate and porous, with spinous granules ; exterior of corallites 

 densely covered with small lacerate spines. Breadth of largest specimen 46 cm., height 

 12-7 cm. {Verrill.) 



