102 



they send up a smal], granular, slightly-inflated, sinuous paliform 

 process which is not really distinguishable from the columella. 

 Those of the third cycle are smaller and much less exsert than 

 their predecessors ; they send off a large triangular paliform lobe 

 long before they join the columella and in the systems in which 

 five cycles are developed those of the fourth cycle resemble those 

 of the third. Those of the fifth cycle (and of the fourth cycle in 

 the few half-systems in which a fifth cycle is not developed) do 

 not join the columella, but they descend deep into the calicle and 

 become irregularly serrated near their termination. The septa of 

 the inferior cycle which stand immediately on either side of the 

 exsert primaries and secondaries are themselves strongly exsert. 

 The septa have a «dead-polished" appearance, but under the lens 

 they are finely striated in granular fashion. 



The columella consists of a few granular and somewhat con- 

 torted knobs, mingled with the slightly inflated paliform processes 

 in which the primary and secontlary septa terminate. 

 Greatest height from basal scar to summit of the most exsert 



septa about 25 millim. 



Diameter of calicle about 37 » 



18. Stephanotrochus Sibogm n. sp. 



Corallum bowl-shaped, without any bulge where the sidewall 

 meets the base. 



The base, which is covered with a thick, dead, deeply discoloured 

 epitheca, has a central scar from which radiate sixteen great, 

 thick, coarse costaa ; in the furrows between these large costas 

 some faint discontinuous striee are sometimes seen. 



On the lower part of the sidewall costee are indistinct, but in 

 the upper two-thirds there are well-cut, granular, subequal costas 

 corresponding to all the cycles of septa. 



The calicular fossa is circular, deep, and capacious. 



The septa are in six systems and five cycles with a very 

 irregular development of the fifth cycle. In the unique specimen 



