MADREPORA. 79 
the corallites are shorter, often a little thickened, with a number of small immersed ones 
interspersed. In some cases the under surface of the branchlets is almost devoid of corallites. 
The star of the radial corallites consists usually of a narrow primary and a rudimentary 
second series of septa; but sometimes the directives are rather prominent. Corallum very 
porous ; surface spongy reticulate and strongly echinulate ; wall strongly striate (fenestrated 
at first), apparently not echinulate. 
? Indian Ocean. 
66. Madrepora tubigera. 
Madrepora tubigera, Horn, Proce. Acad. Nat. Sci. Philad. 1860, p. 485; Verrill, Bull. Mus. Comp. Zool. 
1864, vol. i. p. 41; Studer, Mitth. naturf. Ges. Bern, 1880, p. 19; Quelch, ‘ Challenger’ Reef- 
Corals, p. 161. 
? Madrepora capillaris, Quelch (non Klunzinger), ‘ Challenger ’ Reef-Corals, p. 161. 
2? Madrepora durvillei, Fowler, Q. J. M. 8. 1886, vol. xxvii. p. 1, pl. 1. 
The following is Horn’s description, which has not been extended by subsequent 
observers : — 
«MM. prostrata, ramis paulum diffusis, stricte ramosis ; ramulis attenuatis (base 3’’’) , apice 
acutis. Corallum porosum, caliculo apicale elongato, cylindrico (3-4"" sepe 5! longo et 3!" 
lato) ; lateralibus tubiformibus spe labellatis et dimidiatis ; stella conspicua.” 
The specimens referred by Quelch to this species have the following characters :— 
Corallum extending obliquely or suberect, much branched. Main branch 1°5 em. thick ; 
branchlets 1°3 to 3°5 em. long and 3 to 6 mm. thick ; some are simple, but the majority 
are bi- or trifid near the base. The more slender ones consist of a much elongate and often 
curved tubular corallite 8 to 14mm. long and 2mm. thick, which bears a few small fragile and 
distant buds. The axial corallites of the stouter divisions are also 2 mm. diameter, but are 
rarely more than 2 or 3 mm. exsert. The radial corallites are usually appressed, labellate, or 
nariform, passing below into short tubular ones (with the outer part of the wall a little 
prolonged) and finally immersed; the more prominent ones are 4mm. long, rather narrow 
and appressed near the base, but the lip is much broader and recurved, 2 mm. across the 
widest part; the length and breadth of the corallites varies with the thickness of the 
branchlet. The tubular ones near the base of the colony are 2 mm. diameter and 1 to 3 mm. 
long ; the immersed ones are a little smaller. In all the radial corallites, excepting perhaps near 
the base of the stouter divisions, the wall is very thin and fragile. In the axial corallites the 
star consists of two well-developed cycles of septa; in the radial corallites the directive septa 
often fuse together in the middle line; the other primaries are moderately developed, but 
the second cycle is usually not noticeable. Corallum extremely porous and reticulate in 
section ; surface reticulate and echinulate. The wall of the elongate tubular corallites is 
costulate ; the coste become echinulate in the lower part of the corallite. The others are 
costulate and echinulate, but the striations become lost near the base of the corallum. 
The fragments referred by Quelch to M. capillaris, Klz., probably do not belong to that 
M2 
