468 Mr. G. Brook on new Species of 



Madrepora j^idchra. 



Madrcjmra cribripora, Bassett-Sniith (non Dana), Ann. & Mag. Nat, 

 Hist. vol. vi. 1890, p. 452. 



Corallum arborescent, branches 1-2 to 1"8 centim. thick, 

 terete, bearing braiichlets or radiating clusters of branchlets 

 at intervals of 2'0 to 5 centim.; branchlets elongate, simple 

 or subsimple, 3-5 to 9 centim. long, 8 to 12 millim. thick, 

 gradually attenuate ; the angle of the branchlets varies from 

 '6{f to 90°. Apical corallites 3 millim. diameter, about 2 5 

 millim. cxsert ; those of the branchlets rather smaller. 

 Lateral corallites all spreading at right angles, excepting 

 near tlie apex of a branchlet, all short, tubular, a little vari- 

 able in length, and exhibiting considerable variation in 

 diameter. Length subimmerscd to 1*5 millim., diameter 0'75 

 to 2 millim. The aperture of the larger corallites is usually 

 a little oblique, and in some cases the inner part of the wall 

 is only slightly developed, whilst the outer is elongate, giving 

 a tubo-labellate form ; the inner part of the wall is, however, 

 rarely absent, excepting in the older parts of the corallum, 

 where the majority of the corallites are inmiersed. The 

 outer part of the wall is usually a little thickened in the 

 larger corallites, but the aperture remains over 1 millim. in 

 diameter. Star of the apical corallites consisting of six well- 

 developed subequal sej)ta, the second cycle rudimentary ; in 

 the lateral corallites the star is rudimentary, the directives 

 usually recognizable, and sometimes two or, more rarely, four 

 others. Corallum very porous, surface reticulate and echinu- 

 late; wall striato-reticulate, echinulate in the case of the 

 stouter corallites. 



Keeling Island ; Tizard Bank. 



Madrepora samoensis. 



Corallum cespitose from a broad, rounded, incrusting base j 

 height of corallum 24 centim., breadth 28 centim. Branches 

 very stout and much divided. The main branches usually 

 become divided into eight or ten secondary ascending 

 branches, which increase in length towards the centre of the 

 corallum ; the outer ones are 3 to 5 centim. long, the inner 

 ones 12 or 13 centim.; these branches are often 2 centim. 

 thick, not terete, but, ou ing to crowding, they are more or less 

 angular in section ; the secondary branches bear a third series 

 of ascending branchlets 2 to G centim. long and 1 centim. 

 thick, those directed outwards being longest and most nume- 

 rous. All the divisions are onl}^ slightly tapering and have 

 a blunt apex. Apical corallites 3 millim. diameter or less in 

 the case of the smaller subdivisions, scarcely exsert ; wall 

 thick, very porcms, margin rounded. kStar very distinct, the 



