464 Mr. G. Brook on new Sjyecies of 



and 1 to 1*4 centim. thick, frequently angular below, but 

 more tapering above; the apices are usually 1*7 centim. 

 apart. Those in the centre are chiefly simple, but may bear 

 a few proliferous corallites ; others, particularly near the 

 margin, are divided. Apical corallites 2'5 to 3 millim. 

 diameter, cylindrical, scarcely exsert. Lateral corallites 

 small, crowded, tubular or tubo-labcUate, spreading at right 

 angles, wall thin and porous; they are 1*5, rarely 2, millim. 

 diameter, and seldom over 2*5 millim. long, a little unequal, 

 with small and delicate ones between. On the lower part of 

 the branchlets the prominent corallites are not so numerous 

 and the wall is thickened. Proliferous corallites 5 millim. 

 long and 4 millim. wide (including the lateral buds). Star 

 usually indistinct, but the directive septa are sometimes 

 prominent. Corallum rather dense, surface finely reticulate 

 and echinulate, wall striato-echinulate. 



The type specimen appears to consist of two circular colonies 

 fused together. 



Samoa. 



Madrepora macrostoma. 



Corallum subcorymbose or umbellate, 33 centim. broad and 

 15 centim. high, consisting of crowded erect branches springing 

 from an obconical fastigiate cluster of dead coral. Branches 

 4 centim. long, simple or consisting of two or three subparallel 

 divisions about 1 centim. thick, scarcely tapering. Apices a 

 little over 1 centim. apart. Apical corallites 2"5 to 3 millim. 

 thick and 1 millim. exsert. Lateral corallites broad, round, 

 and ascendinG;, tubo-labellate above, 3 millim. Ions: and 2 to 

 2*5 millim. diameter ; aperture large and circular, wall very 

 thin. Star well developed but deep, consisting of twelve 

 prominent septa ; lower down the corallites become thickened, 

 verruciform, or immersed. Corallum very porous and reticu- 

 late in section, surface openly reticulate, wall striato-reticu- 

 lato, echinulate near the base. 



Mauritius. 



Madrepora ornata. 



Corallum stout, arborescent, branches elongate, below laxly 

 divided, 2 to 3 centim. thick, often oval in section, divided 

 into a cluster of branches at the apex, the whole densely 

 covered witli short ramiculi 8 to 13 millim. long and 5 to 7 

 millim. thick, and about 1 centim. apart, with numerous very 

 short or innnersed corallites between. Apical corallites 3 

 millim. diameter, 1 to 1-5 millim. exsert; wall thick, margin 

 ruonded, aperture about 1 millim. Lateral corallites short, 

 round, nariform, with thickened wall and rounded margin, 



