OF DENISON UNIVERSITY. 
85 
MONTICULIPORID.®, Nicholson. 
Zoarium with tubular cells, which are thin walled and polygonal 
below, above they are bent more decidedly towards the sur- 
face, are of nearly equal size throughout, more or less thickened and 
rounded, but never lipped nor separated by vesicular tissue. Zoari- 
um occasionally frondose, but never composed of two distinct layers 
of cells entirely separated by the epithecal membranes. A distinct 
section of this family typified by the following genus will no doubt 
soon be separated from the same and made an independent family. 
Genus STENOPORA, Lonsdale. 
Zoarium ramose. Cells of the mature region more or less annu- 
lated periodically, with large spiniform tubuli at the angles and straight 
diaphragms, frequently operculate. Species often erroneously referred 
to Chcetetes. 
XII. Stenopora Ohioensis, sp. ft. 
{Plate VIII, Fig. 12, a, b, c, d, e.) 
Branches sub-circular dividing at intervals of about 30 mm. show- 
ing faint traces of bilateral arrangement in the immature region. 
In the immature region the cell walls are thin and polygonal. In 
the mature region the cell walls become strongly and closely an- 
nulated by periodical thickenings, crossed by thin diaphragms at the 
annuls. Spiniform tubuli of large size occupy the cell angles, others 
of smaller size are found on the intermediate cell walls, encroaching 
below upon the cell cavities as vertical ridges. Well preserved speci- 
mens show operculate mouths. Cells irregular in size, the smaller 
more angular, but not distinguishable in vertical section. About 10 
cells occupy a length of 2 mm; branches 5.6 mm. thick. 
Locality a?id position. Flint Ridge. 
XIII. Stenopora carbonaria, Worthen. 
{Plate VIII, Fig. 13, a, b, c.) 
Branches of larger size than the last, 8.9 mm. thick. Cell walls 
not distinctly annulated ; cells larger, crossed by more distant dia- 
phragms, operculate, operculse visible both in cross and vertical sec- 
tions, also in hand samples. Large spiniform tubuli at most of the 
angles of the cells, intermediate spiniform tubulae wanting. Some 
