314 PEOFESSOE P. M. DUNCAN ON THE 



the dredgings, and of a number of forms from shallow water, proves that the shape of 

 the peduncle and base of the corallum varies according to external conditions. To 

 separate the forms which have peduncles attached to foreign bodies from those which 

 are pedunculate but free, and with or without a scar, is not possible, according to the 

 results of the above-mentioned examination, except on the plan of a necessary artificial 

 di-s-ision of a great and closely allied set of forms. Cemtoci/atlius, a genus founded by 

 Seguenza to admit pedunculate forms, is thus clearly only a subsection of the Caryo- 

 Ijhyllice ; and I propose to absorb it. 



There is a very elegant coral which was dredged up from a depth of 705 fathoms. 

 No. 88, first expedition of the ' Porcupine,' and which belongs to the species Cerato- 

 cyathus ornatus, Seguenza'. 



It appears to belong to the pedunculate CaryophylHw which have a thick granular 

 epitheca. I have therefore named the form Caryophyllia seguenzce; for there is a 

 Caryo])hyllia ornata described by Seguenza. 



</ Caryophyllia seguenzje. Dune. (Plate XLIV. figs. 4-6.) 

 Syn. Ceratocyathus ornatus, Seg. 



The corallum is short, conical, compressed, subgibbous, and has a very small, short, 

 and twisted peduncle. 



The epitheca is stout and very granular. 



The calice is elliptical and open. 



The columella is formed of three or more twisted processes, and is well developed. 



The pali are long, and are granulated laterally. 



The septa are very unequal, the last cycle being rudimentary, and very small. The 

 larger septa are thick at the margin, and exsert. There are six systems of septa ; and 

 the fifth cycle is nearly complete. 



The costse are unequal, and they are prominent near the calicular margin. 



Height of corallum ^q i^^h ; length of calice ^ inch. 



Caryophyllia' with the fourth cycle of septa incomplete. 



There are several specimens of species of Caryophyllice which have unequal septal 

 systems owing to the imperfect development of the fourth cycle. This peculiarity is 

 not accidental, or even produced by the forms not having reached their full gi-owth ; 

 for it persists in tall, full-grown corals. It characterizes the Cretaceous Caryophyllia 

 cylindracea, Reuss, and the existing Caryophyllia herteriana, Duchassaing, of Guade- 

 loupe. In consequence of this alliance with a common Cretaceous type, it is requisite 

 to examine the forms with the incomplete fourth cycle very carefully and critically. 



The following is the diagnosis of Caryophyllia cylindracea, Eeuss, a species from the 

 ■Upper and Middle White Chalk". 



' Op. cit. p. 431. - MM. Milne-Edwards and Jules Haime, op. cit. vol. ii. p. 19. 



