25 



2g. Stephanotrochus weberianus n. sp. Plate III. Fig. 22, 220. 

 Stat. 284. 8 43'.! S., i2/°i6'.7E. 82S m. 1 Ex. 



Corallum bowl-shaped, with a strong bulge and thickening where the sidewall joins 

 the base. 



The base. which is covered with a dull epitheca, has a central wart-like scar from 

 which costa; radlate, the costoe of the first two cycles being distinct but not prominent ridges 

 while those of the lower cycles are fine strioe. 



On the sidewall the costse, which are all granular and of equal size, gradually become 

 more and more distinct as they approach the calicular margin. 



The calicular fossa is circular, deep, and capacious. 



The septa appear to be regular, but are, in fact, very irregular owing to the occasional 

 absence from some of the half-systems of those of the fifth cycle. The primaries and secondaries 

 (twelve in number) are large and conspicuously exsert above all the others ; they send up a smal 1, 

 oranular, 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 

 cvcle 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 contorted knobs, mingled with 

 the slightly inflated paliform processes in which the primary and secondary septa terminate. 

 Greatest height from basal scar to summit .of the most exsert septa about 25 millim. 

 Diameter of calicle „ 37 » 



30. Stephanotrochus Sibogcv n. sp. Plate III. Fig. 23, 23a. 

 Stat. 88. o°34'6N., 119 S'.j E. 1301 m. 1 Ex. 



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 costae; in the furrows between these large 

 costse some faint discontinuous striae are sometimes seen. 



On the lower part of the sidewall costae are indistinct, but in the upper two-thirds there 

 are well-cut, granular, subequal costae 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 there are 74 septa, of which 21 are larger and more 



SIBOGA-EXPEDITIE XVI tl. 4 



