254 VAUGHAX : clisiophyllum inoletonense. 
tinued variation along the initiated direction would result in 
further differentiation of areas. 
Bearing in mind, however, the Carcinophylloid character of 
the young stage of Clisiophyllum ingletonense, we must look in 
another direction for the ancestor of our species. 
It would seem justifiable to search for an early Carboniferous 
coral having the following characters : — 
Thick sej)ta and inner wall, thick mesial plate, the beginnings 
of lamellae, and a narrow peripheral zone of broad vesicles. 
As yet we are not acquainted with such a form, although 
the Clisiophyllum from 7 of Burrington Combe (N. Mendips), 
figured in Q.J.G.S., Vol. 68, Plate 31. Fig. 3, seems to take us 
back a certain distance along the right line. 
Of the descendants of this group of Clisiophylla. we have 
several instances in Dy (Yoredalian), but connecting links are at 
present wanting and we must await their discovery. 
APPENDIX. 
Clisiophyllum omaliusi Haime. Plate XXXVIII. Figs. 2a, 2b. 
This species satisfies the definition of Clisiophyllum given 
by Dana and is, for that reason, introduced here. 
C. omaliusi is extremely abundant in the Avesnes Area (N.E. 
France) where it occurs in the " Zone d'Etroeungt " — a limestone 
series correlated by L'Abbe A. Carpentier with the Modiola-heds at 
the base of K in the Bristol Area (Ann. 80c. Geol. du Xord, Vol. 37 
(1908). p. 33). Prof. Jules Gosselet had pre\aously figured an 
external view of this coral (Esquisse Geol. du Nord de la 
France, Fascicle 1 (1880). Lille, PI. V., Fig. 16) and assigned the 
beds in which it occurs to the top of the Famennian. In my 
opinion, these beds should, more prol)ably, be assigned to 
(Rep. Brit. Assoc. 1909, Winnipeg). 
NOTES ON THE SPECIES. 
Horizontal section. Fig. 2a. 
Central Area. 
This area is large, well bounded, reticulate, and traversed com- 
pletely by fine close-set radial lamellae, equal in number to the major 
septa and, in many cases, clearly continuous with them across the 
dividing line between the medial and central areas. The regular 
concentric intersections are more and more closely approximated 
towards the centre, their continuity across lamellae indicating that the 
tabulae have few discontinuities. 
The differentiation of an inner nucleus is adumbrated by increased 
thickening and by the occasional introduction of intercalated lamellae. 
There is no true mesial plate, but the cardinal lamella is con- 
tinued across the centre and slightly thickened there. 
