98 



12. Trochocyathus (Thecocyathus) rhombocolumna n. sp. 



The thecal wall is marked with fine transverse rugae, somewhat 

 as in T. cincticulatus tnihi. The septa and pali are strongly 

 echinulate. 



Septa in six systems and four complete cycles ; the primaries 

 are large and coarse, as also are, but not to such a marked 

 degree, the secondaries, both primaries and secondaries being 

 much more exsert than the septa of the lower cycles. None of 

 the septa unite with one another. 



Pali lamellar, before all the septa except those of the last 

 cycle; those opposite the tertiaries are much the largest. 



Columella formed of four large rugose prisms arranged in a 

 rhomb. 



The unique specimen is dead and broken and is also the sub- 

 ject of a malformation on one side, so that a completer diagnosis 

 is not possible. 



13. Trochocyathus [Thecocyathus) virgatus n. sp. 



This species has a very strong resemblance to Paracyathus 

 striatus Phil. (<ƒ. Duncan, Trans. Zool. Lond. VIII, p. 319, PI. 

 XL11I. Figs. 9 — 13 and X, p. 240, PI. XLIX. Figs. 4-10) from 

 the Mediterranean, but is not al all compressed and has a copious 

 epitheca. 



Corallum attached, cylindro-conical, encrusted to within a very 

 short distance of the calicular margin with a thick dead epitheca 

 through which costae here and there erop out. Above the well- 

 defined limit of the dead epitheca is a vitreous epitheca, which 

 invades the lip of the calicle, but does not conceal the trenchant 

 finely serrated costae. 



The septa, which are in six systems and four complete cycles, 

 are very regular and are exsert, those of the first two cycles 

 being more exsert than those of the third and fourth. Their edges 

 though thin and trenchant are finely crenulate, and their surfaces 

 are most elegantly ornamented with radiating crenulate stria?. 



