] 92 MADEEPORARIA. 



and are frequently curved. They usually bear one or two small appressed buds, certain of 

 which become elongate and tubular ; such buds are, however, rarely situated near the apex 

 of a corallite. The upper surface of the branches, between the elongate corallites, is occupied 

 by a niunber of shorter, less spreading, and often appressed corallites, scattered very irregu- 

 larly, tubular or hemicotyloid in form, with a few subimmersed ones in the lines of fusion. 

 At the margin of the corallum the subdivisions are short and stunted, some of the axial corallites 

 being here 2*5 mm. diameter at the margin and only 2 to 3 mm. exsert ; wall very thick. Star 

 distinct, consisting of 6 subequal primary septa and a very narrow second cycle in the marginal 

 corallites, but in other situations less developed, without the second cycle. Corallum very 

 dense; surface finely echinulate ; wall closely echinulate, but not in rows. 



Some of the specimens have prominent suberect corallites on both sides of the flabellum. 



Pacific Ocean : Tahiti, Macclesfield Bank. 



a. Tahiti. H.M.S. 'Challenger.' 85. 2. 1. 13. ^ 



b. Papeete, Tahiti. H.M.S. ' Challenger.' 80. 11. 25. 219 (part), pyP^^- 



c. Macclesfield Bank, 32 fath. H.M.S. 'Penguin.' 92.10.17.17. (Dead colony.) 

 d-j. Macclesfield Bank, at various H.M.S. ' Penguin.' 92. 10. 17. 21 to 27. 



depths between 30 and 41 

 fath. 

 k. ? ? 93.4.7. 130. 



Division IV. 



10. Subgenus DISTICHOCYATHUS. 

 Madreporoe distichce, M.-Edwards & Haime, CoraUiaires, t. iii. p. 163. 



Corallum more or less distinctly flattened and extending in one plane. Axial corallites 

 compressed, though sometimes not so at first, giving rise to flattened branches with the most 

 prominent corallites confined to the lateral margins. The posterior surface is usually not 

 provided with corallites of any kind, and sometimes the anterior surface is also without 

 corallites ; at others the anterior surface is more or less arched and bears short corallites 

 chiefly, with occasionally a few which are elongate and form twigs. The corallum is not so 

 much flattened in M. parilis and M. angulata as in the other species, but the chief divisions 

 arise laterally. 



208. Madrepora elegans. 



Madrep<»-a elegans, M.-Edwards & Haime, CoraUiaires, t. iii. p. 163, pi. E 1. fig. 3. 



Corallum flabellate, chiefly in one plane. Branches elongate, much flattened, more or 

 less sinuous and with fusions which are more numerous in some specimens than in others ; 



