MADREPORA. 141 
144, Madrepora diversa. (Plate XVI. fig. B.) 
Madrepora diversa, Brook, Ann. Mag. N. H. 1891, vol. viii. p. 461. 
Corallum cespitose from a broad incrusting base, 10 em. high and 18 em. broad. 
Branches 4°5 cm. long, 1°3 to 18 em. thick, simple or divided into 2 to 5 little-spreading 
digitiform branchlets about 2-5 em. long and 1 em. thick, obtuse at the apex. Axial coral- 
lites 3°5 to 4 mm. broad, scarcely exsert. Radial corallites chiefly tubular, with a more or 
less oblique aperture, very unequal in length and diameter; all are ascending. The larger 
ones are 3 to 6 mm. long and 2 to 2°5 mm. diameter, slightly compressed ; wall thick, but 
only slightly rounded at the margin; smaller nariform or subimmersed corallites occur 
between the others quite to the apex ; a few are proliferous and 5 to 8 mm. long. About 
2 cm. from the apex the prominent corallites are nariform or tubo-nariform, with a thick and 
strongly curved outer wall ; at the base nearly all are immersed. Star indistinct, often only 
the directive septa are recognizable. Corallum moderately porous ; surface strongly echinu- 
late ; wall finely striato-echinulate. 
Indo-Pacific Ocean : Diego Garcia, Torres Straits. 
a. Diego Garcia. G. C. Bourne, Esq. [P.]. 91.4.9. 4. (Type.) 
6. Thursday Island. Saville-Kent Coll. 92. 6. 8. 309. 
** Branches provided with numerous short proliferous corallites or twigs. 
145. Madrepora spectabilis. (Plate XVIII. fig. B.) 
Madrepora spectabilis, Brook, Ann. Mag. Nat. Hist. 1892, vol. x. p. 462. 
Corallum corymbose, 28°5 cm. diameter, base 14°5 em., outer branches oblique and pro- 
hiferous, fusions rare, the upper surface only slightly convex. On the under surface of the 
outer branches the subdivisions are horizontal, frequently acervate, 1 to 2°7 cm. long, and 
bear numerous irregular and spreading tubular corallites,5 mm. or more in length and about 
2'4 mm. diameter, others are nariform or subimmersed. Main branches 6 em. long and 
erect near the centre of the corallum, but near the margin the length is 8 or 9 em. and the 
branches are arched, with the subdivisions chiefly on the outer side; the diameter at the base 
is usually 2 em. and 1°5 em. at a point about 1 cm. below the apex ; the central branches are 
simple, blunt, digitiform, or may be divided near the base into two or three branchlets, the 
basal parts are usually angular in section owing probably to crowding ; the apices are about 
2°5 em. apart; the greatest diameter (including corallites) is often 2°5 cm. in the middle of 
a branch. Axial corallites very stout, hemispherical, 6 to 7 or even 8 mm. diameter, aperture 
15mm. The radial corallites vary considerably in form and regularity in different parts of 
the corallum ; on the marginal branchlets nearly all are tubular or subtubular, with the inner 
part of the wall more or less incomplete, and extend at an angle of about 45°; length 
2 to 25 mm., diameter 1°5 to 1°75 mm. ; wall a little thickened excepting in the inner part, 
U 
