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 TZ. recurvatus Pourtalés (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. 1864, p. 477, pl. 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 
cost 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. SrePHANOTROCHUS, Moseley. 
ll. Stephanotrochus nitens, Alcock. PI. ii. figs. 6, 6a. 
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 cost, which radiate from 
