124 MADREPOEARIA. 



122. Madrepora cuspidata. 



Madrepora cuspidata, Dana, Zoophj-tes, p. 485, pi. xlii. fig. 1 ; M.-Edwards & Haimo, Coralliaires, 

 t. iii. p. 149; Verrill, Bull. Mus. Comp. Zool. 1864, vol. i. p. 41 ; Eathbun, 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 cm. thick and 5 to 15 cm. 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 cm. high and 24 cm. 

 broad from a base 8'o 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 cm. long. Axial corallites cylindrical, 2 to 3 mm. diameter; the broader 

 ones have a larger aperture and are sometimes 3 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 M. cuspidata. The 

 figure given by Dana does not lead one to suppose that this species belongs to the subgenus 

 Lepidocyathus. 



Pacific Ocean : Tahiti, Ponape. 



B. Corallum variable in form. Radial corallites little prominent, excepting near the apex 



of the branchlets. 



123. Madrepora rubra. 



Madrepora rubra, Studer, MB. Akad. Wiss. Berlin, 1878, p. 529, pi. 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 1'5 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 



