MADEEPOEA. 127 



form. Branchlets on the upper surface 25 to 7 cm. long and 8 mm. thick below. Axial 

 corallites 2 to 25 mm. thick, 1 to 2 mm. exsert ; aperture sometimes small, at others funnel- 

 shaped. Eadial corallites short, broad, and very spreading, crescent-shaped, crowded so as 

 to give a serrate effect to the branchlets ; wall thick at the base, but tapered towards the lip ; 

 2'5 or even 3 mm. diameter and rarely over 1-5 mm. long, aperture wide. The star is very 

 prominent, and usually consists of 12 septa; the primary series sometimes equal, at others 

 only the directives are broad. Corallum porous and reticulate in section; surface reticulate 

 and echinulate ; wall striate, the striae dentate below. 



One of the specimens in the Strassburg Museum referred by Ortmann to M. convexa, 

 Dana, appears to belong here. It differs from the Berlin specimens chiefly in having longer 

 and rather stouter branchlets on the upper surface (8 to 10 mm. thick). 



In the British Museum specimens, one of which forms a corymbose and pedicellate 

 clump, 34 cm. wide and 13 cm. high, the central branches are 7 cm. long and 1 cm. thick. 

 The radial corallites are gutter-shaped, with a curved lip, and extend almost at right angles; 

 the wall is often thickened, especially towards its base, length 2 to 3 mm., diameter 2 to 2'5 mm. 

 A few immersed corallites occur between the prominent ones ; the latter become more distant 

 below, then ring-shaped, and finally immersed. 



Singapore {Berlin Museum) ; Indian Ocean {Strassburg Museum). 

 a, b. ? ? 93. 4. 7. 122 & 127. (Types.) 



127. Madrepora sarmentosa. (Plate XXII.) 



Madrepora sarmentosa. Brook, Ann. Mag. N. H. 1892, vol. x. p. 462. 



Corallum flattened, bushy, extending obliquely, with crowded short branchlets on both 

 upper and lower surfaces. Height 25 cm., breadth 32 cm., thickness about 7*5 cm. near the 

 middle; base oval, incrusting, 17 cm. by 9 cm. Main branches 2 to 3 cm. thick, fused 

 together so as to form a solid mass near the base, but free and closely divided near the apex 

 of the colony. Surface both above and below covered with large immersed corallites, over 

 1 mm. diameter, with a star of 12 septa; sometimes the primary septa are well developed, at 

 others narrow and subequal. The whole upper surface is studded with short, erect, and 

 blunt twigs, simple or in groups of three or five from a common base, apices usually about 

 1*5 cm. apart. Near the base the twigs are usually under 1 cm. long and 5 to 7 mm. thick; 

 more distally the length gradually increases to 2 cm., and the diameter to 8 or 10 mm., or 

 more in the case of compound twigs. Axial corallites 3'5 to 4'5 mm. diameter, subhemi- 

 spherical, wall thick and reticulate; aperture small, with a star of 12 septa, the directives 

 most prominent. Radial corallites on the basal parts subimmersed and dilated ; on the distal 

 divisions swallow-nest shaped, broad nariform or sublabellate ; the majority have the upper 

 margin nearly at right angles to the axis of the twig; length 2 to 3-5 mm., diameter 2 to 

 3 mm., the outer part of the wall is usually thick and convex, especially in the sublabellate 

 or half-tubular corallites, which have a broad apex ; aperture large, with a star of 6 septa,, 

 which are not usually well developed and may sometimes be almost indistinguishable. The 



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