168 
PALAEONTOLOGY OF NEW YORK. 
Fenestella (Polypora) brevisulcata. 
PRATE XL, FIGS. 12-15. 
Fenestella brevisulcata, Hall. Trans. Albany Institute, vol. x, abstract, p. 26. 1881. 
“ ( Polypora) brevisulcata. Report of State Geologist for 1885, advance sheets. Expl. pi. 40, figs. 
12-15. 1886. 
Bryozoum infundibuliform, fronds large. Branches moderately slender, width 
above a bifurcation .33 mm., increasing to .66 mm., angular or sub-angular, 
becoming flattened, and concave immediately below a bifurcation, with a 
row of small nodes at irregular intervals, along the middle of the branch, 
which is occasionally carinated ; bifurcations distant. Interstices wider than 
the branches. Dissepiments comparatively strong, width .30 mm., rounded, 
very slightly depressed below the plane of the branches, five in the space of 
9 mm. Fenestrules oval, length about 1.25 mm., width from .40 to .60 mm. 
On the celluliferous face the branches are rounded. Dissepiments rounded, 
depressed. Fenestrules of the same size as on the opposite face. Cell aper¬ 
tures in three and four ranges, sixteen in the space of 5 mm., separated by 
less than the diameter of an aperture. 
This species may be distinguished by its angular branches, which become 
flattened as they increase in size and have a depression along the middle, 
immediately below a bifurcation. 
Formation and locality. Upper Helderberg group, Walpole, Ontario, Canada. 
Fenestella (Polypora) striatopora. 
PLATE XL, FIGS. 16-19. 
Fenestella striatopora, Hall. Trans. Albany Institute, vol. x, abstract, p. 23. 1881. 
“ ( Polypora) striatopora, Hall. Report of State Geologist for 1885, advance sheets. Expl. pi. 40, 
figs. 16-19. 1886. 
This form very closely resembles F. (P.) quadrangular is, and may possibly be 
only a variety of that species. The longitudinal disposition of the cell aper¬ 
tures is very distinct, the ranges sometimes being separated by comparatively 
prominent ridges ; at other times the margin of one side of the cell aperture 
is very strongly elevated, coalescing with adjacent margins longitudinally, and 
forming an elevation which has the appearance of a prominent ridge separating 
the ranges of apertures. 
Formation and locality. Upper Helderberg group, Falls of the Ohio river. 
