ïS 



X Paracyathus Edw. & H., Duncan. 



It is almost impossible to identify the species of this genus without actual comparison 

 of specimens. I have restricted the term to those species in which the pali are confused with 

 the columella, otherwise I do not see how the line is to be drawn between this genus and 

 Trochocya th u s . 



18. Paracyathus Agassizi Duncan. 



Paracyathus agassizi Duncan. Transactions of the Zoological Society of London, VIII, 1S74, 

 p. 319, pi. XLIII. figs-. 5—8. 



Stat. 256. 5°26'.6S., I32°32'.5E. 397 m. 1 Ex. 



I identify the single specimen with some doubt, having at first been inclined to regard 

 it is a variety of Trochocyathus ( Thecocyatkus) virgatus. 



Distribution. Atlantic, off the coast of Portugal, Arafura Sea. 



19. Paracyathus pruinosus, n. sp. Plate III, fig. 17, lya. 



[Station 96. S. E. of Pearl Bank, Sulu Archipelago 15 m. 2 Ex.] 



I include this species among the deep-sea fauna because, although it was dredged in 

 only 1 5 metres of water, it was associated with such forms as Deltocyathus magnificus, Tro- 

 chocyathus carvophylloides and ThccocyatJuis virgatus, and not with any shallow-water species, 

 lts nearest relative is Paracyathus striatus Phil. (Duncan Trans. Zool. Soc. VIII p. 319 and 

 X p. 240), an Atlantic species. 



Corallum very dense and heavy, short or of moderate height, straight or curved, mode- 

 rately compressed, and having an encrusting base. 



Costffi evenly scabrous or hnely granular-echinulate, distinct only near the calicular 

 margin and soon becoming hidden by epitheca. 



Calicle much filled by crowded septa and oali and by a large columella of crowded 

 pinnacles : all these structures — septa, pali, and columella-pinnacles — have a sort of crys- 

 talline appearance, being covered with close wavy lines of confluent or semi-confluent granules. 



The mouth of the calicle is elliptical, and the major axis is on a very slightly lower 

 plane than the minor. 



Septa thick, very close-set, in six systems of four cycles with a few of a fifth cycle in some of the 

 half-systems. All are moderately exsert, those of the lowest cycle a little less so than those of the others. 



Pali thick, up-standing, close-set, either prismatic or sublaminar, in two crowns, very sharply 

 delimited from the septa, and in most places, but not everywhere, fairly well delimited from 

 the columella. Those opposite to the first two cycles of septa are simple, but those opposite 

 to the septa of the third cycle are very deeply cleft into two (sometimes into three) lobes. 



Columella large, elliptical, slightly convex, not deep-set, consisting of a dense crowd of 

 discrete pinnacles which are prismatic by mutual compression. 



