126 MADEEPOEAEIA. 



surface almost destitute of branches, but the branchlets on the lateral and upper surfaces are 

 very numerous ; they are short, spike-shaped, and simple, 6 to 7 mm. thick at the base, 

 rarely divided above. Axial corallites about 2'5 mm. wide, with very porous edges and very 

 distinct star of 12 septa. In many axial cups small or rudimentary septa of a third cycle 

 are present, and in a few of larger size they are large and well developed. Radial corallites 

 very unequal and variable, about 1*5 mm. wide, immersed and distant on the under surface 

 and over a large part of the upper surface, becoming verruciform at the base of the branchlets, 

 and very short, open, round nariform above, where they are often crowded ; star of 12 well- 

 developed septa; in corallites which are not verruciform the directive septa are exsert. 

 Coenenchyma porous in the younger parts, becoming closely reticulate and dense below; 

 surface roughly and closely echinulate ; wall strongly striate. ( Quelch.) 



This remarkable species presents two characters which had not previously been observed 

 in specimens of the genus, viz. exsert directive septa, and in certain corallites the presence of 

 a third cycle of septa. I have since observed the latter character in several other species. 



The following additional notes on the type specimen will be of interest : — The branchlets 

 are oblique, 1 to 2 cm. long and up to 7 mm. thick at the base, distinctly tapering, the 

 apices about 1 cm. apart. Axial corallites 25 to 3 mm. diameter, scarcely exsert ; wall 

 provided with broad plate-like striae. Corallites on the under surface and on the main 

 branches immersed and distant, 1'5 mm. diameter, star very prominent, the directive septa 

 usually exsert ; those near the base of the branchlets have usually a thick ligulate border 

 and are 2 mm. in diameter ; those nearer to the axial corallite have not such a thick wall 

 and are tubular, at an angle of about 45°, many have the inner part of the wall not free, 

 but in the more prominent ones (1'5 to 2 mm.) the inner part of the wall is quite distinct; 

 wall veiy porous, and armed with dentate plates ; surface of the coenenchyma often tabulato- 

 echinulate ; septa very prominent in all except the younger corallites. 



East Indies : Banda. 

 a. Banda. H.M.S. 'Challenger.' 85.2.1.14. (Type.) 



C. Corallum variable. Radial corallites usually more or less crescent-shaped, thickened at 

 the base, but generally thin at the margin. 



126. Madrepora studeri. (Plate XXV.) 



Madrepora sureuhsa, Studer {non Dana), Mitth. naturf. Ges. Bern, 1880, p. 20. 

 Madrepora convexa, Ortmann, Zool. JB. 1889, Bd. iv. p. 508 (part.). 



CoraUum cespitose or corymbose and pedicellate. The under surface is complanate in 

 the corymbose form, the branches being fused into flattened alciform groups, with numerous 

 immersed coralUtes and short thick tubular ones near the margin. On the pedicel, which in 

 one specimen exists only on one side of the corallum, there are numerous short twigs, which 

 spread horizonally and evidently represent the shorter marginal branches of the cespitose 



