34 
PROFESSOR P. M. DUNCAN ON THE STRUCTURE. 
dental causes. Another, though perhaps less important, character is the smoothness of 
the septa, which present neither perforations, nor synapticula, nor granulations. Tabulae, 
however, there are none, the interseptal characters being open from top to bottom. 
Among the Bugosa this character is only found in the family of the Cyathaxonida ?, to or 
near which, therefore, our coral must find its place. From the genus Cyatliaxonia it 
differs in being attached by a broad base, and also by the absence of a septal fossula. 
Haplopliyllia paradoxa , Pourtales. 
“ Corallum subcylindrical, short, fixed by a broad base ; epitheca thick, wrinkled, 
reaching higher than the calice, and forming around it several concentric circles as if 
representing the separated borders of several superposed layers. Calice circular, fossa 
deep. Septa smooth, without granulations or perforations, not reaching the border of 
the calice ; like all the internal parts of the calice, their surface is like enamel. Colu- 
mella composed of two smooth conical processes, very thick at the base and tending to 
fill up the chambers. Eight septa, larger and connected with the columella, alternating 
with smaller ones which touch the columella at a much lower level. A further cycle is 
indicated by small ridges of the wall-surface in some of the chambers. No distinction 
can be made between primary and secondary septa among the eight larger ones, as they 
all appear equal. 
“ Height about \ inch ; diameter of the calice ^ inch. 
“ The coral was living when obtained ; the polyp was of a greenish colour, but was not 
otherwise examined when fresh. After having been in alcohol it could be lifted out entire 
from the calice, presenting an exact cast of the chambers. The mouth is surrounded 
by a circle of about sixteen rather long tentacles, bluntly tuberculated at the tip. 
Outside the circle of tentacles extends a membranous disk with radiating and concen- 
tric folds.” 
This unique specimen was dredged up in 324 fathoms off the Florida reef. 
It is evident that this interesting form and that which was dredged off the Adventure 
Bank have much in common. Both must be classified amongst the Cyathaxonidoe ; and 
it is quite possible that future dredgings may discover intermediate forms which will 
necessitate the absorption either of the genus Haplopliyllia or of Guynia. At present 
the shape of the closely allied forms, their septal number, the nature of the columellse, 
and the characters of the epithecal structures must he considered to separate them 
generically. The large septum, so visible in some of the specimens of Guynia annulata , 
constitutes in itself a differentiation. 
Admitting the generic alliance to be of the closest, Guynia and Haplopliyllia will form 
with Cyatliaxonia the three genera of the family Cyatliaxonidce of the section Bugosa. 
Y. In describing some fossil corals from the Miocene deposits of Australia in 1865, 1 
noticed some species of a new genus in the following manner* : — “ The new genus Conos- 
* Ann. Mag. Nat. Hist. 1865, xvi. p. 185. 
