MADREPORA. 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 
15cm. 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 are subequal, 2 to 3 mm. long, thick-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, pl. i. fig. 8, pl. iv. fig. 7, 
pl. ix. fig. 12; Ortmann, Zool. JB. 1888, Bd. iii. p. 152. 
Corallum corymbose, often 30 em. broad, very porous and fragile. Branches 1°5 to 
2 em. 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 coral”.es 3 to 4mm. broad, mostly short 
(2 to 8 mm.), but on some of the twigs they are 5 sami 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 2mm. 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 em. 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. 
