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.) 

 kevistriata, 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 (Polypora) l^vistriata. 



plate xxxv, figs. 14-16. 



Fhtatella {Polypora) IcBvUtriata, Uall. Report of State Geologist for 1882. Expl. pi. 28, figs. 14-16. 1883. 



Bryozodm infundibuliform. Branches strong, width above a bifurcation .50 

 mm., increasing to 1 mm., angular, carinated ; carinas 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. 



