192 MADREPORARIA. 
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 number 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). | dypes. 
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. 
? ——? 93. 4. 7. 130. 
Division IV. 
10. Subgenus DISTICHOCYATHUS. 
Madrepore distiche, M.-Edwards & Haime, Coralliaires, t. 1. 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 /ateral 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. 
Madrepora elegans, M.-Edwards & Haime, Coralliaires, t. ui. p. 163, pl. 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 ; 
