1 1 



Costce equal, in the form of very thin microscopically-serrate carince, which extend from 

 the calicular margin to the acuminate base. 



Calicular orifice horizontal, the fossa deep. Septa in .six systems and five cycles, the 

 fifth cycle being undeveloped in two of the half-systems. Those of the first cycle are pre- 

 eminently large and exsert, besides being thicker than the others ; those of the other four 

 cycles diminish successively in size and exsertion from the 2"'^ to the 5'^. All the septa are 

 straight and finely and sparsely granular, and all but those of the first cycle have the edge, 

 within the calicular fossa, slightly sinuous. 



Columella deep-seated, consisting of a fair number of twisted pinnacles arising from a 

 basal network. Only the se]jta of the first two cycles meet the columella, and then only at a 

 great depth in the calicular fossa. 



Height of corallum 10 millim. 



Major diameter of calicle 9 „ 

 Minor „ „ „ 8 „ 



III. Subgenus Conotrochus Seguenza. 



Only differs from Ccratotrochiis in having the theca immersed in an epitheca showing 

 transverse growth-rings ; the epitheca forms for the calicular orifice a well-marked boundary 

 line in which the outer ends of the summits of the septa are somewhat sunk. 



9. Ccratotrochus (Conotrocliiis) fiinicohiiinia n. sp. Plate I. Fig. 6, 6a. 



Stat. 95. 5°43'.5 N., ii9°4o' E. 522 m. i Ex., dead. 

 Stat. 100. 6° 11' N. I20°37'.5E. 450 m. 2 Ex., dead. 



The dead corallum, which is all that we possess of this singularly elegant species, looks 

 much like a shortened form a of Conotrochus typus Seg. from the Sicilian Tertiaries, to which 

 it is evidently nearly related, as also to P letirocyatluis drunneus Moseley. 



Corallum attached, conical, short, the calicular orifice perfectly circular. The costae, 

 which correspond in number to the septa, are all of one size and form, but are somewhat 

 hidden by a thin epitheca in which broad rings of accretion are noticeable. 



The rounded summits of the septa are just visible above the sharply defined calicular 

 margin. The septa are in six systems and four complete cycles, the primaries being the largest 

 and the others gradually diminishing in size in serial succession ; they all descend very deeply 

 into the cup. 



The columella is a stout isolated column of remarkable height, composed of over a 

 dozen long ribbon-like .strands, which are all tightly twisted together in one solid spiral like a 

 piece of rope. 



Height of corallum 12.5 millim. 

 Diameter of calicle 11.5 „ 



