MADEEPORA. 81 



Radial corallites broad, tubo-nariform, short, widely open, wall striato-echinulate ; septa in a 

 singl(! narrow cycle, the inner directive broadest. Axial corallites exsert, but scarcely larger 

 than the radial ones. Corallnm porous, reticulate in section ; surface reticulate or striate 

 and echinulate. 



In the 'Challenger' specimen the small branchlets are seen to be produced from elongate 

 tubular corallites, 2 ram. diameter near the apex, the terminal 4 to 6 mm. usually without 

 buds. Radial corallites spreading, nariforra or tubular, with the inner part of the wall 

 scarcely free, 1*5 to 2 mm. wide, the outer part of the wall rarely 2 mm. long ; the aperture 

 is wide and circular. Towards the base of the branches many of the corallites have a ring- 

 shaped border, and in them a second cycle of septa is more or less completely represented. 

 The species is closely related to M. tubigera. 



East Indies : Kingsmill Islands, Banda. 



a. Banda. H.M.S. ' Challenger.' 86. 12. 9. 269. 



69. Madrepora dilatata. 



Madrepora tennis, Ortmann {mn Dana), Zool. JB. 1888, Bd. iii. p. 152. 



Corallum consisting of a bushy clump 10 cm. high and 16 cm. broad. Branches much 

 divided from the base ; distal divisions 2 to 3 cm. long and 4 to 5 mm. thick, often forked at 

 the apex. Axial corallites 2 to 2'5 mm. thick, not over 2 mm. exsert : wall very porous and 

 not much thickened. Radial corallites rather distant, elongate, appressed, tubular, with the 

 distal part dilated and the aperture very oblique ; the form is dimidiate, length 4 to 5 mm., 

 diameter 2 mm., becoming short, and finally immersed below. Star well developed, but the 

 septa are delicate. Corallum very porous ; surface spongy and strongly echinulate ; wall 

 very porous and striato-reticulate ; the striae are well marked, rather distant, and finely 

 dentate. 



This species approaches M. tenuis, Dana, but differs from the specimens I have referred 

 to tHat species in the stouter axial corallites, the more elongate and dilated radial corallites 

 with very oblique aperture, and the better developed star. 



Pacific Ocean : Tongatabu [Strassburg Museum) . 



70. Madrepora dendrum. (Plate XXXIII. figs. A, B.) 



Madrepora dendrum, B.-Smith, Ann. Mag. N. H. 1890, vol. vi. p. 452. 



Corallum " arborescent subcespitose ; stem solid, strong ; surface finely echinulato- 

 striate, bearing curved, simple or proliferous, gradually tapering branchlets 2"5 cm. long and 

 3 mm. thick, with compressed nariform calicles, tending to form into rows showing two very 

 long (broad) septa; apical calicles 1 mm., exsert, stem distinct ; under surface shows branches 

 sinuously curved, with spreading margin, not coalescing, with few immersed corallites." [B.- 

 Smith.) 



