6 



PROP. P. M. DUNCAN ON THE MADREPORARIA 



Paracyathtjs mergttiensis, sp. nov. (Plate I. figs. 12-14.) 



The corallura has a broad expanded base and a narrower calice, 

 the stem constricted, otherwise cylindrical, and taller than broad. 

 The calice is elliptical, very deep, and the columella is small, con- 

 cave, with small and crowded processes. The septa are in five 

 incomplete cycles, slightly exsert, unequal, crowded, and project- 

 ing into the calice ; spinulose at the sides. The pali are single, 

 and often tall, before the secondaries and primaries, and are small 

 and nodular ; those before the tertiaries are numerous and tall, 

 and some are like twisted open lamellae. The costse are large, 

 subequal, broad, and marked with granules. 



Height of corallum 8'5 millim., breadth of calice 6*5 millim,, 

 length of calice 8 millim. The septa, pali, and columella are of 

 an intense Prussian-blue colour. Locality, Mergui Archipelago. 



Subfamily Turbinolid^e eeptantes, Dune. {Revision of Genera fyc, 

 Journ. Linn. Soc, Zool. vol. xviii. p. 34). 



Genus Polycyathtjs, Dune. op. cit. p. 34. 



Poltctathus Verrilli, sp. nov. (Plate I. figs. 15, 16.) 



The colony covers about 10 square inches, the corallites are 

 variously spaced, rarely very close, small, cylindrical, short, and 

 their costse pass over the basal structure, which is minutely 

 granular. The calices are widely open, circular, or slightly wavy 

 in marginal outline. Septa slightly exsert, unequal, sharply 

 granular at the sides, extending like a circular zone inwards, and 

 surrounding the narrow, deep, circular fossa ; rarely with four 

 cycles, usually with three and a few of the fourth order, or only 

 three cycles. Costse faint on some corallites, well seen on others, 

 much broader relatively than the septa, low, nearly equal, but 

 those of the primaries and secondaries may project near to the 

 margin ; they traverse much or all the space between the coral- 

 lites, or they may not pass far. Epitheca pellicular and granular. 

 There are pali before all septa except those of the last cycle, or 

 they may exist before all the septa in some calices with three 

 c\ clefl of septa ; broadest before the secondaries. The pali reach 

 well into tin; "zone" of septa. Columella small, deep, con- 

 cave, papillose. 



Eeight <>\' ordinary corallites 2-2-5 to 3 millim., width of 

 Calice - 1" 2*5 millim. ; distance between corallites 2 to 4 millim. 

 Locality, Mergui Archipelago, encrusting. 



