156 PEOF. p. M. DUNCAN ON THE 



Mergui*. The large central (or more or less near the edge) calice 

 is very remarkable, and it does not appear to have been described 

 or figured. It is a deep funnel-shaped or rather elongate calice 

 (2 centira. long), with long septo-costge, which pass into those of 

 the several small calices which surround it in a ring and extend 

 towards the circumference. The axial space is deep, and at least 

 three times as long as it is broad (length 3 millim.); and its floor 

 is formed by small trabeculge from the ends of the septa. The 

 septa are nearly horizontal at their upper parts near the edge of 

 the calice, and they then plunge down rather rapidly to the sides 

 of th.e axial space, which they bound closely. They are well de- 

 veloped, numerous at the outer part of the calice, and in three 

 cycles at the axial space (24). They are. distinctly separate 

 (except at their junction parts) in the upper part of the inter- 

 septal loculi, which are very visible. The primaries are the largest 

 and have no others united to them ; the secondaries are slightly 

 smaller, and also are usually simple and, like the primaries, reach 

 from the margin to the axial space without being joined by any 

 others. The tertiary septa are very compound ; they are single 

 at the axial space and bulky there ; and they are composed 

 further out of several sets of septa which unite one with the 

 other, and each set is composed of other septa which have 

 coalesced. 



In a well-developed system the third septum is thin, straight, 

 and long, and reaches the axial space ; it is joined just without on 

 either side by a well-developed septum at an acute angle, and 

 still farther out each of these is joined by the junction of three 

 small septa. So that each tertiary septum is composed of an 

 ao-gregate of seven septa. Hence the septal arrangement of this 

 great calice is of five cycles in six systems. The margins or 

 edges of the septa are profusely ornamented with well-developed 

 dentations, some thick and others thin, and all jagged at 

 their tops and granular at their sides. They are largest on the 

 primary septa. The granular dentations increase in height and 

 breadth, becoming wart-like near the outer ends of the septa and 

 where these merge into those of the surrounding calices. The 

 septa thus ornamented are usually, but not invariably, the higher 



* The species is described in the ' Hist. Nat. des Corall.' vol. iii. p. 20 ; and 

 the notes given above are upon points left unconsidered by Milne-Edwards and 

 Jules Haime. 



