Madrepora in the British Museum. 469 



mimaiy septa often nearly meet in the middle line, but in the 

 smaller corallites the directives are broadest; a second cycle 

 is also moderately developed. Around the apical corallite 

 the lateral corallites are frequently arranged in subregular 

 longitudinal rows. The lateral corallites are nariforra or 

 short-tubular at first, with the inner part of the wall more or 

 less incomplete, the outer part thickened and very porous ; 

 they are 2 to 3 millim, long and about 2 millim. diameter, 

 liows of smaller subimmersed corallites are situated between 

 the prominent ones, but the linear arrangement is lost 3 to 5 

 centim. from the apex. At a point about 2 centim. from the 

 apex the prominent corallites become more thickened and 

 bear buds ; they are then about 4 millim. long and nearly 3 

 millim. diameter. Such proliferous corallites occur at inter- 

 vals of 5 to 8 millim. over the whole of the upper part of the 

 corallum ; a few become more elongate and may attain a 

 length of 2 centim. At a point varying from 2'5 to 6 

 centim. from the apex of a branch or branchlet the whole of 

 the corallites become short, and on the inner sides of the 

 branches almost all of them are immersed. The star of the 

 lateral corallites not destined to form proliferations is quite 

 indistinct, usually only the directive septa are recognizable. 

 Corallum very porous ; surface spongy reticulate and echinu- 

 late, becoming regularly reticulate below ; wall striate and 

 fenestrated, margin not rounded. 



Samoa Islands [Rev.'S. J. Whitmee). 



Madrejyora spathulata. 

 Corallum prostrate, complanate below. Branches I'D 

 centim. thick, flattened on the under surface, with numerous 

 immersed and short nariform corallites, and a few spreading 

 tubular ones between ; branchlets in the general plane with 

 one or several tubular corallites near the apex, often 5 millim. 

 long and 2 millim. thick. Branches on the upper surface 

 arcuate, 7 centim. long, and usually consisting of two branches 

 fused together, so as to be somewhat oval in section, 1*8 by 1 

 centim., usually ] centim. thick up to within 1 centim. of the 

 apex ; divided nearer the apex into two to four branchlets, 

 most of which are also imperfectly divided into two ; apices 

 blunt. Apical corallites 2 to 2*5 millim. thick, scarcely 

 exsert ; wall thick and very porous ; aperture usually small, 

 but sometimes funnel-shaped. Lateral corallites crowded, 

 spreading at right angles, 2 millim. broad and long in the 

 upper parts, sj)athulate, and the rounded lip sometimes 

 recurved ; below the wall is not so prominent and a little 

 thickened, and at the base of the branchlets the corallites are 

 all subimmersed or immersed; aperture nearly 1 millim., but 



