CERATOCYATHUS. 19 



CERATOCYATHUS Segdenza. 



Having received, through the kindness of Mr. J. G. Jeffreys, 

 some specimens of Ccratoci/athns ornatus Seguenza, from the 

 dredgings of the Porcupine Expedition off the West Coast of 

 Ireland, I have satisfied m3'self that the genus does not belong to 

 the fiimily of Carjophyllida) at all, but to Trochosmilidtw If the 

 European species from the deep-sea dredgings and the Sicilian 

 tertiary beds does not show very distinct dissepiments (at least 

 in the specimen of which Mr. Bicknell made a section for me), it 

 is because the interspaces have been filled up, as a careful inspection 

 shows plainly. The pali. wliich give to these corals so striking a 

 resemblance to the typical Caryophyllias, are found, when traced to 

 their origin, to be formed by lobes of the septa, and not by inde- 

 pendent growths rising from the bottom of the calicle. 



Ceratocyathus prolifer Pourt. 

 Plate 111 , figs. 8, 9, 10. 



CoraUum free when adult, conical, curved, showing no trace of 

 attachment. Cost* finely granulated. No trace of epitheca. The 

 wall rather thick and of compact texture. Calicle circular or 

 slightly elongated in the direction of the curvature ; fossa moder- 

 ately deep. Septa finely granulated in six systems and five cycles, 

 but the fifth cycle generally incomplete in some of the systems. 

 The septa of the third order, and sometimes those of the fourth, 

 have a paliform lobe, which in older specimens becomes merged in 

 the columella. (This is the case in fig. 9.) Dissepiments rather 

 massive, about eight or nine occurring in a chamber (Plate III., fig. 

 10). The base of the coral has a tendency to become filled up. 

 Columella spongy with papillose convex surface ; in the young 

 it is little developed, and sometimes lamellar, so that an isolated 

 specimen would be liable to be classed as a Placosrailia. 



The propagation is by buds inside of the calicle of the parent, not 

 nnfrequently two or three growing out at the same time, but in 

 such cases one of them outgrows and stunts the others. The parent 

 is probably killed by the growtJi of the offspring, which fills the 

 whole calicle before becoming free, but the wall being very strong 



