MADEEPORA. 193 



the flattening takes place in an antero-posterior direction ; the posterior surface is nearly flat 

 and the anterior more or less arched; 40 cm. long or more, 2 cm, broad, and under 1 cm. 

 thick. Secondary branches lateral, subalternate, 1*5 to 12 cm. long, very much flattened 

 above but more rounded near their bases. All the branches are practically devoid of corallites 

 on the posterior surface ; laterally they bear subalternate, flattened, tubular corallites or 

 simple branches, 0'4 to 4-5 cm. long and 3 to 5 mm. in longest diameter, often only 2 to 

 2*5 mm. in the shortest ; those over 8 mm. long usually bear a series of small lateral corallites, 

 which at first are immersed, but, with the formation of a wall around them, become half- 

 goblet-shaped or nariform j some of these in turn become tubular and give rise to new out- 

 growths. The anterior surface of the corallum bears a number of scattered, subimmersed, 

 and half-goblet-shaped corallites, certain of which at irregular intervals become tubular or 

 subcorneal and project at right angles to the surface of the flabellum ; these are the only 

 prominent corallites not in the general plane ; they may be 3 to 12 mm. long, 2 mm. diameter 

 at the apex, gradually becoming thickened towards the base. Apex of the axial corallites 

 oval in section, about 2 by 3 mm., upper part of the wall rounded, with an aperture 1 mm. in 

 diameter. The star consists of 12 septa ; the primaries are well developed, the others only 

 slightly prominent. Corallum very dense ; surface with narrow longitudinal furrows, the 

 whole covered with fine echinulations. 



The habitat of the type specimen in the Paris Museum is not recorded. 



Philippine Islands. 



a, b. Manila. R. Brown, Esq. [P.]. 93. 4. 7. 168 & 171. 



209. Madrepora teneUa. (Plate XXIX. fig. E.) 



Madrepora tenella, Brook, Ann. Mag. N. H. 1892, vol. x. p. 464. 



Corallum much flattened, flabellate ; allied to Madrepora elegans, M.-Edw. & H., but more 

 delicate. Stem and main branches much flattened or only slightly so ; the smaller divisions 

 are usually more or less rounded. Branches 7 mm. broad and rarely over 3 mm. thick, some- 

 what sinuous, divisions and corallites almost all lateral : fusions frequent and irregular. 

 Simple lateral corallites give rise, by increase in size and the development of buds, to twigs 

 ranging from 5 mm. to 4 cm. in length, the larger one provided with a secondary series of 

 lateral and divaricate twigs. Axial corallites 1 to 1'5 mm. diameter, a little compressed, 

 usually 3 mm. exsert. Radial corallites distant, compressed, nariform at first but soon 

 becoming tubular and very spreading ; diameter 1 mm. ; length 1 to 5 mm. ; those which are 

 longer usually bear distant buds. There are no immersed corallites and the whole of the 

 corallum, excepting the lateral margins of the branches and twigs, is usually devoid of corallites 

 of any kind. The star consists of 6 moderately-developed septa ; aperture a little contracted 

 if circular, but usually elliptical. In some parts of a colony the more delicate twigs bear 

 alternate, short, nariform to subtubular corallites on the lateral margins, which are much closer 



