MADEEPOEA. 137 



138. Madrepora dactylophora. 



Madrepora digitifera, Studer {non Dana), MB. Akad. Wiss. Berlin, 1878, p. 530. 



Corallum stout, corymbose, without fusions, sometimes 40 cm. broad. Central branches 

 simple, but those at the margin are more or less subdivided; length 5 to 6 cm., diameter 

 15 cm. Axial corallites 4 mm. diameter, 1 mm. exsert; wall very thick. Radial corallites 

 short, broad, tubular, spreading at right angles ; aperture oblique, margin very sharply defined ; 

 the majority arc subequal, 2 to 3 mm. long, tliick-walled, broader at the apex than at the 

 base ; lip frequently 3 mm. diameter, oblique, sharply defined, with small aperture ; a few, 

 which are more elongate, are proliferous. Immersed or short labellate corallites are scattered 

 between the others, and all are more unequal in length near the base of the branches. A 

 few prominent corallites have the inner part of the wall wanting. Corallum rather dense; 

 surface spongy-echinulate ; wall striato-echinulate. 



Pacific Ocean : Salawatti, New Guinea [Berlin Museum). 



139. Madrepora eurystoma. 



Madrepora eurystoma, Klunzinger, Korallenth. d. roth. Meeres, Th. ii. p. 16, pi. i. fig. 8, pi. iv. fig. 7, 

 pi. ix. fig. 12 ; Ortmann, Zool. JB. 1888, Bd. iii. p. 152. 



Corallum corymbose, often 30 cm. broad, very, porous and fragile. Branches 1'5 to 



2 cm. thick at the base, much divided, with numerous short proliferations near the apex. 

 Axial corallites 3 to 4 mm. diameter, about 2 mm. exsert; wall moderately thick, margin a 

 little rounded, aperture 1 mm. diameter. Radial corallites 3 to 4 mm. broad, mostly short 

 (2 to 3 mm.), but on some of the twigs they are 5 mm. long, half-funnel-shaped to tubular, 

 with an oblique aperture, and usually broader at the margin than at the base ; wall more or 

 less thickened, but very porous ; aperture wide, often 2 mm. A few small thin-walled coral- 

 lites are scattered between the prominent ones, and towards the base of the branches all 

 become very short, with a thin cylindrical wall and wide aperture ; very few are completely 

 immersed. The star consists of one or two cycles of septa, which taper away towards the lip 

 of the corallites, so as to appear situated deep down. Corallum very porous and reticulate in 

 section; surface spongy-reticulate and echinulate, but denser in parts; wall striato-reticu- 

 late, becoming striate and echinulate on the stouter corallites. 



Var. parvula. 

 A variety from Diego Garcia consists of an elongate, prostrate, and flattened branch, 



3 by 2 cm. diameter and 20 cm. long, bearing chiefly immersed corallites on the under surface. 

 On the upper surface the ultimate divisions are erect, 1 to 3 cm. long, and about 8 mm. 

 diameter. Axial corallites usually about 3 mm. diameter, with a wide aperture and relatively 

 thin wall. Radial corallites short, rarely over 2 mm. diameter, and scarcely so spreading as in 

 the type. 



Indian Ocean : Red Sea, Diego Garcia, Maldive Islands, Torres Straits. 



