74 MADREPORARTA. 
high ; base 15 cm. diameter. The branches are about 1 em. long and 1 to 1:3 em. thick 
near the centre of the colony, simple, bifid or trifid, with the subdivisions subparallel; those 
nearer the margin are shorter and more frequently subdivided ; the outer divisions of the 
marginal branches extend horizontally, but are rarely 3 cm. long. Many of the apices bear 
short proliferations. Axial corallites scarcely 2 mm. diameter, a little exsert, but provided 
with bud-corallites almost to the margin. Radial corallites prominent and a little rounded, 
if within 2 or 38cm. of the summit, those below usually immersed or subimmersed ; pro- 
minent corallites nariform, tubo-nariform, or dimidiate, sometimes in longitudinal rows, as 
indicated by Dana, 2 to 38 mm. long, very spreading, about 1 mm. diameter; wall scarcely 
thickened ; aperture narrow and elongate. A few of the corallites near the summits are 
stouter and more elongate, and indicate new proliferations. Star not well developed in the 
prominent corallites, but more marked in those which are subimmersed or immersed. 
Corallum rather porous above ; surface spongy echinulate ; wall finely striato-echinulate. 
Another specimen from the same locality has more proliferous branches and_ less 
spreading corallites, which remain prominent to a greater distance from the summits than in 
the specimen described above. 
Var. crassilabia. 
Corallum half corymbiform from a lateral attachment. Marginal branches subhori- 
zontal, with numerous stout tubular corallites and short twigs, 7 to 14 mm. long, clothed 
with subimmersed and immersed corallites. Upper surface with erect digitiform branchlets 
about 1 em. thick. Radial corallites prominent, nariform or dimidiate, spreading almost at 
right angles, with thick dense wall and rounded margin; a few short, nariform corallites 
are scattered between the others; aperture oblique and elongate, length 2 to 3 mm., 
diameter nearly 2 mm.; the more prominent ones are arranged in longitudinal rows. The 
corallites gradually become shorter towards the base of the branchlets, but scarcely any on 
the superior surface of the corallum are completely immersed. It is possible that Dana’s 
figure represents a specimen with thick-walled radial corallites. 
Pacific Ocean: Tahiti, Fiji, ? Capricorn Islands. 
a, b. Tahiti. H.M.S. ‘Challenger.’ 85. 2.1.5 & 85. 2.1. 4. 
ec. Fiji. F. M. Rayner, Esq. [P.]. 62. 2.7.1. (Var. crassilabia.) 
?d. Capricorn Islands. Saville-Kent Coll. 92. 6. 8, 303. 
60. Madrepora paxilligera. 
Madrepora pawxilligera, Dana Zoophytes, p. 452, pl. xxxiv. fig. 1; M.-Edwards & Haime, Coralliaires, 
t. ii. p. 157; Verrill, Bull. Mus. Comp. Zool. 1864, vol. i. p. 42; Duncan, Journ. Linn. Soe. 
Lond. 1886, vol. xxi. p. 20; Rathbun, Proc. U.S. Nat. Mus. 1887, vol. x. p. 17; Ortmann, 
Zool. JB. 1888, Bd. ili. p. 152 (non Quelch, ‘Challenger’ Reef Corals, p. 154; non B.-Smith, 
Ann. Mag. N. H. 1890, vol. vi. p. 453). 
Dana gives the following particulars :— 
Corallum very broad, cespitose, pedicellate, plane above ; base of frond solid, disk-shaped, 
