160 
PALAEONTOLOGY OF NEW YORK. 
Fenestella (Polypora) cultellata. 
l’LATE XXXVI, FIGS. 3-22; AND PLATE XLI, FIG. 9. 
Fenestella cultellata, Hall. Trans. Albany Institute, vol. x, abstract, p. 21. 1881. 
“ ( Polypora ) cultellata, Hall. Report of State Geologist for 1SS2. Expl. pi. 29, figs. 3-22. 1883. 
“ “ “ “ Report of State Geologist for 1885, advance sheets. Expl. pi. 41, 
fig. 9. 1886. 
Bryozoum infundibuliform, fronds large, strong; near the base there are usually 
elongate projections, which frequently have their distal extremities attached 
to foreign substances, serving as additional supports to the frond. Branches 
moderately strong, width above a bifurcation .40 mm., increasing to 1 mm. 
or slightly more ; angular when perfectly preserved, with a slight carina and 
occasionally with prominent, oblique, conical nodes ; when slightly worn or 
macerated they are rounded or flattened and smooth ; bifurcations near the 
base at intervals of from 10 to 25 mm., at some distance above, from 
30 to 90 mm. Interstices narrower than the branches. Dissepiments 
slightly oblique, width .50 mm., five or six in the space of 5 mm., on the 
same plane and much expanded at their junction with the branches. Fenes- 
trules broadly oval, sometimes nearly circular, length about .50 mm. 
On the celluliferous face the dissepiments are rounded and depressed, very 
frequently traversed by narrow channels with sharp margins, which extend 
for a short distance on the branches. Fenestrules narrower than on the 
opposite face. Cell apertures in from three to seven ranges, eighteen in the 
space of 5 mm., very closely disposed, usually in contact; margins distinctly 
elevated. At frequent intervals along the middle of the branch the margins 
of the apertures are prolonged into elongate, sharp, node-like elevations, 
having a height of about .50 or .60 mm. and a length of .75 mm. 
This species is very abundant at the locality cited, and may be readily dis¬ 
tinguished by the peculiar elevations on the celluliferous face, and the channels 
traversing the dissepiments. 
Formation and locality. Upper Helderberg group, Falls of the Ohio river. 
