MADREPORA. 161 



A. Coralhtm corymbose, with or vnthout confluent branches. If the central branches are 



long the habit is bushy. 



171. Madrepora variabilis. 



Madrepora variabilis, Klunzinger, Korallenth. d. roth. Meeres, Th. ii. p. 17, pi. i. fig. 10, pi. ii. figs. 1 & 

 5, pi. V. figs. 1 & 3, pi. ix. fig. 14 ; Mobius, Beitr. z, Meeresfauna Mauritius, p. 45 ; Ortmaan, 

 Zool. JB. 1888, Bd. iii. p. 152 (part.) ; ibid. 1889, Bd. iv. p. 505. 



Madrepora coalescens, Ortmann, Zool. JB. 1889, Bd. iv. p. 509, pi. 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. Axial 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 aud 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 aud 2 to 

 3 mm. broad. 



Forma tuinida, Klz. 



A small cespitose form with stout dilated radial corallites 3 to 4 mm. broad, closely 

 resembling those of M. hemprichi. 



Forma pachyclados, Klz. 



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, Klz. 

 1 Madrepora aff. tenuispicata, Ortmann, Zool. JB. 1888, Bd. iii. 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 modera/tely appressed. 



Forma coalescens. 

 Madrepora coalescens, Ortmann, Zool. JB. 1889, Bd. iv. p. 509, pi. xiii. fig. 5. 



Corallum corymbose, upper surface flattened or a little convex. The branches on the 



