100 MADREPORARIA. 
2mm. in diameter, and 2 to 3 mm. exsert; wall a little thickened, margin not rounded. 
Radial corallites 2 to 4 mm. long, and 1 to 15 mm. diameter, chiefly labellate, with small 
often styliform lip, but the larger ones are half-tubular as in M. corymbosa; the upper 
corallites are very unequal in length and diameter, and are usually more appressed than in 
M. corymbosa, the lower ones and those on the main divisions are mostly immersed. Star 
indistinct, the inner directive septum usually recognizable, and sometimes the other primaries 
also, particularly in the immersed corallites. Corallum rather porous ; surface subreticulate, 
ribbed and echinulate ; wall strongly striate and echinulate. 
Var. globata, Klunzinger. 
Colony massive and convex from an incrusting base. 
A specimen from Diego Garcia forms a large rounded subvasiform colony, the vase 
being produced as in M. arcuata by the overlapping and fusion of the posterior lobes of an 
originally arched and flabellate specimen. In the character of the under surface this speci- 
meh comes nearer to specimens from Tahiti than to those obtained by Klunzinger from the 
Red Sea. 
Generally speaking the Pacific form has the under surface covered with short usually 
much dilated tubular corallites, and those on the upper surface have a rather porous wall. In 
Red Sea specimens the under surface has no dilated corallites, and the majority are immersed 
or subimmersed ; on the upper surface the wall of the radial corallites is dense and firm. 
The species forms extensive terraces in the Red Sea, and sometimes is very difficult 
to distinguish from certain forms of M. corymbosa. Tahiti specimens are vasiform and 
differ from many Red Sea specimens in various details, particularly im the dilated corallites 
of the under surface and the extremely numerous proliferations on the upper surface. 
Indo-Pacific Ocean: Tahiti, Solomon Islands, Singapore, Ceylon, Diego Garci 
Mauritius, Red Sea. 
a. Red Sea. Dr. Klunzinger [C.]. 86. 10. 5. 31. 
6, c. Tahiti. H.M.S. ‘Challenger’ 85. 2.1. 19& 86. 12. 9. 409. 
d, Singapore. Purchased. 78. 6. 6. 14. 
e. Solomon Islands. Dr. Guppy [C.]. 84. 12. 11. 24. 
?f. Diego Garcia. G. C. Bourne, Esq. [C.]. 92.5. 29. 1. 
g, h. Ceylon. Haeckel Coll. 92. 12. 15. 19, 27 & 29. 
ae i 2? 93. 4. 7. 116. 
is ? Bowerbank Coll. 77. 5. 21. 183. 
k, ——? 2? 93.4, 7.126. (Var.) 
92. Madrepora armata. (Plate X. figs. A, B.) 
Madrepora spicifera, Dana, Zoophytes, p. 443 (part.), pl. xxxiil. figs. 4 & 4a only. 
? Madrepora cytherea, Quelch, ‘ Challenger’ Reef Corals, p. 165 (part.). 
Madrepora armata, Brook, Ann. Mag, N. H. 1892, vol. x. p. 452. 
The small specimen figured by Dana under the name M. spicifera does not appear 
to belong to that species, but, as Dana suggested, may be a young form of M. cytherea. It 
differs from that species in two important points, viz.: the scarcity of proliferous corallites on 
