97 



The columella is sublamellar, consisting of two rugose plates, 

 placed end to end. 



Greatest height of corallum 14 millim. 

 Major diameter of calicle 15 » 

 Minor » » » 10 » 



In general appearance this species has a considerable likeness 

 to a Tropidocyathus lessoni without the wings. 



11. Trochocyathus cavatus n. sp. 



Corallum curved, a little compressed, fixed by a very short 

 somewhat slender cylindrical pedicle, the major axis of the calicle 

 on a very slightly lower plane than the minor axis. All the costse 

 are very distinct and are granular or finely milled. 



Septa in six systems of four almost complete cycles, stout, and 

 rather thickly beset with rows of dark brown granules. There is 

 not much difference in size betweeu the septa of the first three 

 cycles, but those of the fourth cycle are a good deal reduced in 

 size, so that the septa as a whole are alternately large and small. 



Pali columnar, 24 in nurnber, placed opposite all the septa 

 except those of the last cycle. They are all of much the same 

 size, but those of the outer crown (opposite the tertiaries) stand 

 higher in the calicle than those of the inner crown (opposite the 

 primaries and secondaries), and the arrangement in two rings is 

 thus very well marked. 



The columella, which is small and reticulate, is extraordinarily 

 deep-seated, far below the well defined inner ring of pali. 



The interior of the corallum is cinnamon brown, the septa and 

 pali being edged with white. 



Greatest height of corallum 10.5 millim. 

 Major diameter of calicle 8 » 



Minor » » » 7 » 



In appearance this species resembles a slender-pedicled Paracya- 

 thus-, but the pali, though they have something of a pinnacle 

 form, are very distinctly delimited from the columella. 



