MADEEPOEA. 75 



5 cm. thick, convex and naked below. Branchlets digitiform, 6 to 7*5 cm. long and 2*5 to 

 3"75 cm. thick ; erect, subterete, rarely furcate, subacute. Margin of colony with short 

 and incipient branchlets. Axial corallites scarcely 2 mm. diameter, scarcely exsert. Radial 

 corallites a little unequal, very crowded, a little prominent, compressed nariform or some- 

 times dimidiate. Wall striate; aperture oblong ; star scarcely distinct. 



The specimen recorded by Ortmann agrees well with Dana's figure, but the corallites 

 are scarcely compressed. The colony is 20 to 24 cm. wide, and forms a flattened convex 

 clump with a broad incrusting base. The central branches are erect, digitiform, usually 

 simple, but bear numerous budding corallites and very short proliferations rarely over 

 5 mm. long and 4 mm. thick ; they are 2'5 to 4 cm. long and 1 to 1'5 cm. diameter at the 

 base. The marginal branches are not so stout, often forked, and extend obliquely, projecting 

 3 to 3'5 mm. beyond the base. Axial corallites 2 mm. diameter, scarcely exsert; wall 

 moderately thick. E,adial corallites small and very crowded, 1 mm. diameter; thin-walled, 

 more or less ascending, dimidiate, nariform, labellate or gutter-shaped, with a tapered apex, 

 rarely tubular. Adjoining corallites are very unequal in length, but usually not over 2 mm., 

 though on some of the branches a few may attain a length of 3 mm. The proliferous 

 corallites become completely tubular, and are 3 mm. or more in length. The basal parts of 

 the branches bear immersed corallites, with arched nariform ones between, some of which 

 have the wall thickened and hooked. Star of the radial corallites indistinct, usually only 

 the directive septa are prominent. Corallum dense, but reticulate in section. Wall finely 

 striate, echinulate below. The under surface of the marginal branches bears very short 

 appressed and immersed corallites. 



The specimen referred to this species by Quelch differs only in the more unequal coral- 

 lites from one of those referred by him to M. nasuta ; both have ascending radial corallites, 

 but may not really belong to this species. The corallites are compressed nariform to dimi- 

 diate, with immersed or short corallites between, but are not so crowded as is shown in 

 Dana's figure. 



Indo-Pacific Ocean : Tahiti, Fiji, Mergui Archipelago. 



? a. Tahiti. H.M.S. ' Challenger.' 82.5.1.6. { = M. paxilUgera, dvieich.) 



61. Madrepora digltifera. 



Madrepora digitifera, Dana, Zoophytes, p. 454 ; M.-Edwards & Haime, Coralliaires, t. iii. p. 153 (non 

 Studer, MB. Akad. Wiss. Berlin, 1878, p. 530). 



Corallum broad, corymbose, with a solid circular base ; nearly flat above. Branchlets 

 crowded, digitiform, scarcely terete, subacute, 6 to 7*5 cm. long and 8 to 10 mm. thick, 

 often proliferous. Axial corallites a little prominent, scarcely 2 mm. diameter. Radial 

 corallites crowded, divaricate, dimidiate, erect, not at all compressed, 1"5 mm. long ; lip 

 rather thick, with scattered immersed corallites between ; all the corallites are obsolescent on 

 the lower part of the branchlets. Wall of the corallites neatly striate ; star of 6 narrow 

 septa, the outer directive quite prominent. In the prominent corallites the lower part of the 

 wall extends at right angles to the branch. [Dana.) 



