MADREPORA. 95 
52 cm. broad and 10 to 14 cm. high. Under surface complanate; branches crowded and 
coalescent, somewhat flattened below; branches 1 em. thick, with numerous much appressed 
corallites and a few tubular ones, which are lateral in position and give rise to branchlets 
in the general plane; some are simple, 8 to 10 mm. long and 2 mm. thick, others bear lateral 
nariform corallites, others, again, tubular ones, those near the base being elongate and very 
spreading ; immersed corallites almost absent from the under surface. On the upper surface 
the main branches give rise at intervals to clusters of two to five suberect branchlets ; the 
more central ones are erect and simple or forked, 5 cm. long and 6 mm. thick at the 
base, distinctly tapering; nearer the margin of the colony the branchlets are oblique and 
arcuate and bear clusters of 2 to 5 short twigs which are 1 to 2 cm. long and 4 mm. thick ; 
apices 6 to 9 mm. apart. Upper surface of the main branches and base of the branchlets 
provided with numerous large immersed corallites, with an aperture of 1mm. Axial coral- 
lites about 2 mm. diameter, usually about 1 mm. exsert. Radial corallites ascending, 
elongate, labellate, and imbricate, 3 to 4 mm. long and 1°5 mm. thick; apices more or less 
pointed. Corallum very porous and reticulate in section ; surface densely echinulate ; wall 
thin, finely striato-reticulate and echinulate, except in the case of the younger ones. Star 
not recognizable in the prominent corallites or only the directive septa present; in the 
immersed ones it sometimes consists of six very narrow septa. Two specimens have the apices 
of some of the twigs subdivided; in the third the majority are proliferous. 
Mauritius. 
a. Mauritius. Purchased. 78. 2.4. 9 T 
b,c. ? Purchased. 49.1. 4.1 oy ve 
86. Madrepora pectinata. (Plate XXVII. figs. D, E.) 
Madrepora pectinata, Brook, Ann. Mag. N. H. 1892, vol. x. p. 460. 
Corallum plate-like or vasiform, similar to M. conferta and M. hyacinthus in habit, 
2°5 em. thick, Under surface flattened, forming an open network, without projecting 
branchlets; branches 6 to 12 mm. diameter; the stouter ones are usually compressed 
laterally so as to be oval in section. Corallites on the under surface very short, open bursi- 
form or immersed, thus differing entirely from either M. conferta or M. hyacinthus ; they are 
nearly 2 mm. diameter; outer part of the wall rarely 15 mm. long, the inner part not 
prominent; aperture nearly 1 mm.; star imperfectly developed. Branchlets on the upper 
surface rather crowded, usually arranged in groups of 2 to 5 along the course of each 
branch; length 9 to 14 mm., diameter 4 mm., scarcely tapering ; apices about 6 mm. apart. 
Axial corallites cylindrical, 15 mm. diameter or slightly over, rarely over 1 mm. exsert; 
wall thin and aperture large, with a star of 12 septa, none of which are very prominent. 
Radial corallites short, spreading, round-labellate, with curved margin to the lip ; diameter 1-2 
to 1:5 mm., length 1:5, rarely 2 mm.; wall fragile; directive septa scarcely recognizable. 
The corallites are more spreading than in M. conferta, and the apertures are quite distinct 
when seen from above. Corallum rather porous; surface and wall striate and echinulate. 
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