CORALS AND BRYOZOA. 
159 
tures in from three to six ranges, eighteen in the space of 5 mm., separated 
by less than the diameter of an aperture. On some fronds, especially near 
the base, there are prominent, irregularly disposed nodes. 
The non-celluliferous face of this species so nearly resembles that of F. (P.) 
lavistriata, that a satisfactory determination cannot always be made; usually 
the fenestrules are more elongate-oval. On the celluliferous face this species 
may be distinguished by the more prominent cell apertures, their closer dispo¬ 
sition and the absence of striations separating the ranges of apertures. 
Formation and locality. Upper Helderberg group, Falls of the Ohio river. 
FENESTELLA (POLYPOKA) LjEVISTRIATA. 
PLATE XXXV, FIGS. 14-16. 
Fenestella ( Pulypora ) Icsvistriata, Hall. Report of State Geologist for 1882. Expl. pi. 28, tigs. 14-16. 1883. 
Bryozoum infundibuliform. Branches strong, width above a bifurcation .50 
mm., increasing to 1 mm., angular, carinated ; carime with prominent, conical 
nodes, which usually occur opposite the dissepiments, but are sometimes 
irregularly disposed. Interstices narrower than the branches, sometimes not 
more than half the width. Dissepiments comparatively slender, width .33 
mm., five in the space of 5 mm., on a plane with the branches. Fenestrules 
oval, length .60 mm., width about one-half the length. 
On the celluliferous face the branches are gently rounded. Dissepiments 
rounded, depressed. Fenestrules of the same size as on the opposite face. 
Cell apertures in from two to four ranges, eighteen in the space of 5 mm., 
separated by slightly more than the diameter of an aperture; margins dis¬ 
tinctly elevated. Ranges of apertures separated by slight ridges. 
The non-celluliferous face of this species so closely resembles that of F. 
(P.) quadrangular is , that it is difficult to distinguish them. On the celluliferous 
face the apertures are smaller, more distant and more distinctly arranged in 
longitudinal rows, which are separated by ridges. 
Formation and locality. Upper Helderberg group, Falls of the Ohio river. 
