MADREPORA. 161 
A. Corallum corymbose, with or without confluent branches. If the central branches are 
long the habit is bushy. 
171. Madrepora variabilis. 
Madrepora variabilis, Kiunzinger, Korallenth. d. roth. Meeres, Th. ii. p. 17, pl. i. fig. 10, pl. ii. figs. 1 & 
5, pl. v. figs. 1 & 3, pl. ix. fig. 14; Mébius, Beitr. z. Meeresfauna Mauritius, p. 45; Ortmann, 
Zool. JB. 1888, Bd. iii. p. 152 (part.); ibid. 1889, Bd. iv. p. 505. 
Madrepora coalescens, Ortmann, Zool. JB. 1889, Bd. iv. p. 509, pl. xiii. fig. 5. 
Corallum very variable in form, bushy, cespitose, corymbose or horizontal and then 
cespito-foliate with frequent fusions. Outer branches of the colony usually more or less 
horizontal, almost without corallites below. Avxial corallites 3 to 4 mm. broad, little exsert, 
wall thick, margin rounded. Radial corallites chiefly tubular with a rounded margin, but the 
inner part of the wall may be much shorter than the outer, aperture small and rarely central. 
A few of the more elongate ones bear buds and a few very short thin-walled and subimmersed 
ones are scattered between the others. Lower down the corallites are less spreading, shorter, 
but rarely immersed. Corallum dense and compact; surface scarcely porous, finely echinulate; 
wall echinulate, sometimes in rows, but not costulate. The upper corallites are often very 
spreading, but in other specimens rather appressed, a little unequal, 4 to 5 mm. long and 2 to 
3 mm. broad. 
Forma tumida, K/z. 
A small cespitose form with stout dilated radial corallites 3 to 4 mm. broad, closely 
resembling those of M. hemprichi. 
Forma pachyclados, K/z. 
Corallum corymbose, cespito-foliate; branches and branchlets little spreading, 1 to 
1°5 cm. thick or more in the case of the main divisions. Radial corallites usually somewhat 
appressed. 
Forma leptoclados, K/z. 
? Madrepora aff. tenuispicata, Ortmann, Zool. JB. 1888, Bd. ii. p. 153. 
Corallum cespito-foliate or bushy. Branches and branchlets only 5 to 10 mm. thick, but 
the main divisions may be as stout as in var. pachyclados. The elongate tubular corallites 
and the twigs produced from them are very spreading, the other radial corallites may be 
spreading or moderately appressed. 
Forma coalescens. 
Madrepora coalescens, Ortmann, Zool. JB. 1889, Bd. iv. p. 509, pl. xiii. fig. 5. 
Corallum corymbose, upper surface flattened or a little convex. The branches on the 
