13 
DI3SCBIPTI0N OF BILLINGS' HOLOTYPE OF “ C. ANTICOSTIENSIS ’’ 
(G.S.C. 2267) Plate I, figure 6; Plate III, figures la-c 
Major portion of a large mass, sliced transversely and polished. The 
surface shows radiating, circular corallites typically distant, a few in 
contact, with maximum diameter of 2*5 mm. The wall of each corallite 
is raised in a narrow rim from w'hich twenty costse are distinctly seen to 
radiate, at a lower level, into the inter-corallite area. This area is 
depressed, but in some places rises to a subdued straight ridge between 
juxtaposed corallites; consequently the surface appears to be made up 
of polygonal units which contain a single corallite and its “ costse.” It 
must be said at once, however, that no trace of this ridge is to be observed 
in the internal structure. 
In thin sections each corallite is seen to be bounded by an open mesh- 
work made up of septal ridges, which are produced into short, wedge-like 
spines at regular intervals (about 8 spines in 5 mm.) and fused to their 
neighbours at these levels. A section taken at such an horizon of fusion 
will show a circular corallite with a continuous wall made up of septa, 
which are in contact for about two-thirds of their length and then taper 
fairly abruptly inward to an obtuse point. But each septal spine is con- 
tinued outward and slightly downward beyond the corallite boundary into 
the coenenchyme as a “ costa.” When their bases are not seen in the section 
(it will be remembered that they incline slightly downward) these “ costae ” 
will appear as rods or spindles of about 0* 75 mm. in length lying on a circle 
of greater diameter than that of the corallite and separated from their 
neighbours by more or less wide pores. But sections at a level slightly 
higher than this will show septa passing continuously out into “ costae.” 
This is most commonly seen within the zone of septal fusion so that the 
corallite showing this feature probably will have a solid “ wall.” But 
some pores may be cut at such a level. This variation in the appear- 
ance of thin sections is tersely shown in Lambe’s diagrammatic figure, 
Plate I, figure 6a (1899), which, however, is not elucidated in his text. 
But his reference of this figure to his figure 6, which is too generalized, 
is misleading. 
The mural pores, which lie on vertical and horizontal rows, are circular 
and probably have a diameter of no less than 0*25 mm. But the dilation 
of the septal spines and, to a less extent of costse,” toward their bases, 
where they are fused to their neighbours, gives a funnel-like entrance to 
these pores. On account of the septal spines being arranged on horizontal 
and vertical rows, these “ funnels ” have a rounded-quadrangular section 
at their widest part, but assume an oval, then circular, section as they 
lead into a pore. This, of course, happens within a very short distance, 
but it is important because certain authors have attached considerable 
weight to the shape of the pores in Calapoecia. This they have studied 
from the weathered interiors of corallites. It can be seen from the above 
description that the apparent shape of the pore in these cases will depend 
on the depth of weathering, and although a pore may appear to be quad- 
rangular at first sight, it becomes clear when the matrix is carefully 
removed with a needle, that this is the shape of the funnel-like entrance 
and not of the pore itself, which is circular. The term “ funnel ” has been 
11476—2 
