124 MADREPORARTA. 
122. Madrepora cuspidata. 
Madrepora cuspidata, Dana, Zoophytes, p. 485, pl. xlii. fig. 1; M.-Edwards & Haime, Coralliaires, 
t. ii. p. 149; Verrill, Bull. Mus. Comp. Zool. 1864, vol. i. p. 41; Rathbun, Proc. U.S. Nat. 
Mus. 1887, vol. x. p. 15; Ortmann, Zool. JB. 1888, Bd. iii. p. 151. 
Corallum subcespitose, consisting of a cluster of long cuspidate, regularly tapering, and 
nearly simple branches, 2°5 em. thick and 5 to 15 em. long, rising from a common solid 
base. Axial corallites probably 2°5 to 3 mm. diameter, 2 mm. exsert, and tapering a little 
towards the apex. Branches nearly bare of corallites on the inferior side, on the other the 
radial corallites are short sublabellate, erect, and fragile, with immersed corallites between ; 
aperture about 0°7 mm. diameter, circular ; the immersed cells are smaller. Star 6-rayed, 
distinct, the directive septa broadest. (Dana.) 
The specimen recorded by Ortmann forms a cespitose clump 16 em. high and 24 em. 
broad from a base 8°5 cm, diameter. The central branches are erect and simple or sub- 
simple, dilated at the base, and rapidly tapering towards the apex, but the middle part is 
cylindrical ; length 7 cm., diameter 2 cm. at the base. Marginal branches spreading sub- 
horizontally, 10 em. long. Axial corallites cylindrical, 2 to 3 mm. diameter; the broader 
ones have a larger aperture and are sometimes 8 mm. exsert. The radial corallites are 
often shorter on the outer than on the inner side of the branches, but there is not in this 
specimen the marked difference shown in Dana’s figure. 
The main divisions are covered with small, crowded, immersed corallites ; a little above 
the bases of the erect branches short tubular or half-tubular to sublabellate corallites occur 
scattered amongst the immersed ones, these are 1°5 to 1:75 mm. diameter and have the wall 
a little thickened. Nearer to the apex nearly all are more or less prominent, and extend at 
an angle of about 60°; the form is usually gutter-shaped, with a convex margin and thin 
fragile wall ; the length varies from 0°5 to 3 mm., the diameter is not usually over 1°5 mm. 
The apices of the branches frequently bear proliferations from 7 to 10 mm. in length. The 
corallum is rather porous, the surface reticulate, and the wall striato-reticulate. 
There is some uncertainty whether this specimen really belongs to MV. cuspidata. The 
figure given by Dana does not lead one to suppose that this species belongs to the subgenus 
Lepidocyathus. 
Pacific Ocean : Tahiti, Ponapé. 
B. Corallum variable in form. Radiai corallites little prominent, excepting near the apex 
of the branchlets. 
123. Madrepora rubra. 
Madrepora rubra, Studer, MB. Akad, Wiss. Berlin, 1878, p. 529, pl. ii. fig. 4. 
Corallum subcorymbose from a broad incrusting base. Outer branches oblique, short, 
pointed, and proliferous, partly coalescing into an open network. Middle branches simple, 
slender, 6 cm. or more in length, and rarely over 5 mm. thick at the base, gradually tapering 
to an axial corallite 15 mm. broad and 1 mm. exsert. Radial corallites near the base of 
the branches immersed, or with a narrow half-ring shaped border, becoming more crowded 
