Foerste.] 
340 
[May 1, 
top of the more elongate specimens. The polyp walls are always 
more or less strongly wrinkled transversely, the wrinkles being 
chiefly formed by a contraction of the rim of the calyx at some 
point after which the expansion of the polyp walls is again resumed. 
The indications of the septa within are occasionally well marked 
though usually very faint at the surface, or even obsolete, but where 
the specimens are partially weather-worn the septa can be readily 
detected. Their number is usually five in a width of from 3.2 mm. 
to 4 mm. The number of septa varies from seventy-five to ninety in 
the specimens examined. Vertical sections show that the walls of 
the calyx descend abruptly, and that the calyx is from 10 to 12 mm. 
deep. Horizontal sections show that half of the septa disappear 
within half the distance from the exterior to the centre of the cor- 
allum ; the remaining lamellae are twisted towards the centre. On the 
side toward the apertural gap there seems to be an apertural fovea 
quite distinct toward the centre but filled nearer the margin with 
two or three septa which do not reach the centre, at least at the 
same level with the rest. Longitudinal sections also show but very 
few horizontal diaphragms, at least near the upper portion of the 
corallum. On the other hand, numerous striations are seen which 
are perpendicular to the walls of the corallum or run inwards at a 
more elevated angle than this would indicate. In the horizontal 
sections, these are seen to be dissepiments in part at least. Weather- 
worn portions of the exterior seem to indicate that these structures 
in great part are crenulations on the septa, extending laterally in- 
to the spaces between the septa. These crenulations occur at quite 
regular intervals, usually ten or eleven in a length of o mm. The 
sections also seem to indicate that the septal lamella are elevated 
about the fovea. In a specimen from Todd’s Fork believed to be- 
long to this species, they are elevated laterally and anteriorly about 
this apertural fovea. 
This variety may readily be distinguished from the typical form 
in the Niagara at Waldron, Indiana, by its smaller size, a some- 
what less rapid increase of growth, and a less flaring calycular 
border. It is fairly represented at the Soldiers’ Home quarries 
near Dayton, Ohio. The variety is also represented in the cabinet 
of Columbia College from the Clinton conglomerate at Belfast, 
Highland Co., Ohio, where it occurs among the cementing mate- 
rial. 
