CORALS AND BRYOZOA. 59 



on each branch. Width of interstices about equal to that of the branches. 

 Dissepiments moderately slender, abruptly rounded, four in the space of 5 

 mm., slightly depressed below the plane of the branches and not expanding 

 at their junction. Fenestrules quadrangular, varying in width from one- 

 fourth to one-half their length. 



On the celluliferous face the branches are rounded, and the dissepiments 

 much depressed. Fenestrules of the same appearance as on the opposite 

 face. Cell apertures circular, opening laterally, distant about one-half the 

 diameter of an aperture, from twenty to twenty-two in the space of 5 mm., 

 disposed in two ranges, with occasionally one or two additional apertures 

 immediately below the bifurcation : margins thick, elevated, indenting the 

 borders of the fenestrules. The branch, sometimes, has a slightly elevated, 

 very thin carina, which is scarcely perceptible. 



Width of branch above bifurcation .30 mm., increasing to .50 or .60 mm. ; 

 diameter of dissepiments .24 mm. ; length of fenestrules generally, about 

 1 mm. 



Formation and locality. Lower Helderberg group, Clarksville, N. Y. 

 Fenestella (Polypora) stricta, n. sp. 



PLATK XLX, FIGS. 1, 2. 

 FmuUlla EuAnrat Reiwrt of State Geologist for 1882. Expl. pi. 19, figs. 1, 2. 1883. 



Bryozoum probably infundibuliform, compact. Branches moderately slender, 

 rounded, becoming flattened for a short distance before bifurcating, marked 

 by fine, sharp, longitudinal striae. Bifurcations distant, often 15 mm. or 

 more apart. Interstices about equal in width to the branches. Dissepi- 

 ments rounded, seven or eight in the space of 10 mm., expanded at their 

 junction with, and on the same plane as the branches. Fenestrules quad- 

 rangular or elongate-oval, width from one-fifth to one-half the length. 



On the celluliferous face the branches are angular, becoming rounded for 

 a short distance before bifurcation. Dissepiments rounded, much depressed. 

 Fenestrules of the same appearance as on the opposite face. Cell apertures 



