18 



cylindrical shape and in the possession of series of diverticula from the intersep- 

 tal spaces, which diverticula are not visible externally as rootlets but form 

 concentric chambers round the inner true limiting wall of the calicular fossa. 



The present species also seems to resemble T. recurvatus Pourtales (Bull. 

 Mus. Comp. Zool. vol. V. 1878-79, p. 202) in its wrinkled epitheca. 



It also has a remarkable resemblance to the Conotrochus typus of Seguenza 

 (Mem. Accad. Sci. Torino, (ser. 2) xxi. 18B4, p. 477, pi. x. figs. 1, la-d ; but 

 there is no doubt about the pali. 



The corallum is broadly attached, subcylindrical with a barrel-like bulge, 

 and somewhat curved, and is smothered in an epitheca so thick and copious 

 that the edge of the calyx, which just shows clear of it, has a strangled and 

 swollen look. 



The surface of the epitheca is most elegantly ringed or milled, and no 

 costas show through it, though near the calicular margin shallow grooves 

 corresponding with all the interseptal spaces do. 



The calyx is circular and shallow, being almost filled somewhat after 

 the manner of Heterocyathus by the thick close-set and beautifully regular 

 septa the exsert edges of which are milled. 



Nine or ten of the septa are more exsert, but not very much larger, than 

 the rest, and divide the calicle into as many equal chambers, each of which is 

 again subdivided into four compartments by three septa of nearly equal size. 

 The spaces between the septa are mere chinks. 



The pali are nine or ten in number and are opposite the median septa of 

 the principal chambers : they have the form of twisted rods or blunt spires, and 

 are not very clearly separated from the six or seven similar rods that form the 

 columella. In addition to the true pali there is an outer crown of almost 

 paliform thickenings of the edges of the 9 or 10 principal septa. 



The colour of the epitheca is french-gray, glistening near the calicular 

 margin : the septa, etc., are ivory white. 



Off the Maldives, 210 fms. 



vi. STEPHANOTROCHUS, Moseley. 

 11. Stephanotrochus nitens, Alcock. PI. ii. figs. 6, 6. 



Stephanotrochus nitens, Alcock, Ann. Mag. Nat. Hist., Jan. 1891, p. 7. 



Corallum bowl-shaped, heavy dense and stony but not coarse, ivory-white. 



The base is gently convex, has a central scar, and is covered with a dull 

 epitheca : the side-wall, which has a slope of about 85 degrees from the verti- 

 cal, is free of epitheca. The primary and secondary costse, which radiate from 



