146 MADEEPOEAEIA. 



Corallum spreading arborescent, laxly branched. Main branches stout, 2 to 3 cm. 

 thick ; branches long, lax, and turned in various directions, or short, stunted, divaricate, and 

 obtuse at the apex. Elongate branches 15 cm. long and 1'5 cm. thick, little divided, scarcely 

 tapering, except near the apex ; stunted form of similar diameter, but more frequently and 

 divaricately divided ; ultimate divisions 2 to 3 cm. long, 1 to 1*5 cm. thick, scarcely tapering, 

 very obtuse at the apex. A few short conical buds, or abortive branchlets, are scattered at 

 intervals from the base upwards. Corallum rather dense; surface finely and thickly granular, 

 the " granulations " consist, as in other cases, of clubbed spinules with rough apices, or of 

 scabrous narrow plates in rows. Axial corallites very variable in size, sometimes 4 to 6 mm. 

 in diameter, with very thick wall, not exsert, or only slightly so ; in other cases conical, 

 2 mm. exsert, 4 to 5 mm. diameter at the base, and about 3 mm. at the apex. In certain 

 cases, where the terminal divisions are very stout, a single axial corallite does not occur, but 

 instead the apex is occupied by several stout, cylindrical corallites, with only the rounded 

 margin prominent. This clearly is an approach to the condition in the subgenus Isopora. 

 Radial corallites crowded, very unequal and irregular on the upper surface, but more distant 

 below; they are usually short, thick, spreading tubular, with small aperture and rounded 

 margin ; 2 to 2'5 mm. diameter and 2 to 5 mm. long, but most are short. At intervals certain 

 corallites become more elongate and thickened, and develop buds. The inner part of the wall 

 is often not so thick and prominent as the outer, in which case the aperture opens inwards ; 

 the outer part of the waU may project in a point or hooked knob some distance above it. 

 This type of corallite is most frequent in certain elongate branched specimens, which pro- 

 bably constitute a distinct variety. Star well developed, primary septa broad and subequal, 

 the others not so prominent ; wall finely and closely granular, echinulate, the echinulate 

 plates often arranged in rows at the base of the corallites. Immersed corallites are not 

 numerous, and occur only on the under surface of the branches. 



Var. uncinata. (Plate XXXV. fig. E.) 



? Madrepora nobilis, Verrill (non Dana), Bull. Mus. Comp. Zool. 1867, vol. i. p. 40 (part.). 

 ? Madrepora scahrosa, Bassett-Smith (non Quelch), Ann. Mag. N. H. 1890, vol. vi. p. 452. 



Branches relatively elongate and tapering towards the apex ; radial corallites with a 

 rounded margin, tubular with an oblique aperture, becoming uncinate or shovel-shaped ; very 

 unequal in size, often a little compressed. Axial corallites 3 to 4 mm. diameter or a little 

 over, usually 1 to 2 mm. exsert. 



Indo-Pacific Oceaa : Singapore, ? Tizard Bank, Torres Straits, Great-Barrier Reef. 



a, 6. Singapore. Purchased. 78. 4. 1. 1 & 2. (Types.) 



c-f. N.E. Australia. H.M.S. 'Alert.' 93. 4. 7. 101 to 104. 



g. Warrior Island. Saville-Kent Coll. 92. 6. 8. 55. 



h, i. Palm Island. Saville-Kent Coll. 92. 6. 8. 56 & 57. 



j. Port Denison, Saville-Kent Coll. 92. 6. 8. 121. 



