162 PALEONTOLOGY OF NEW YORK. 



the branches. Dissepiments slender, width .30 mm., rounded, depressed. 

 Fenestrules sub-quadrangular, length generally a little more than 2 mm., 

 width from .70 to .90 mm. Cell apertures minute, in from three to five 

 ranges, fourteen in the space of 5 mm., separated by more than the diameter 

 of an aperture ; margins slightly elevated, and separated by comparatively 

 prominent, gently sinuous ridges. 



This species will be readily distinguished, as it is the only flabellate form at 

 present known, from this geological formation. 



Formation and locality. Upper Helderberg group, Onondaga Valley, Onondaga 

 county, N. Y. 



Fenestella (Polypora) perangulata. 



PLATE XXXVn, FIGS. 18, 14. 



Penettella perangvJata, Haix. Trans. Albany Institute, vol. x, abstract; p. 23. 1881. 



" (Polypora) perangulata. Hall. Report of State Geologist for 1882. Expl. pi. 30, figs. 13, 14. 



1883. 



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

 mm., increasing to .80 or .90 mm., acutely angular, with a very slight carina, 

 which is sometimes sinuous. Interstices wider than the branches. Dissepi- 

 ments comparatively slender, width .40 mm., angular, carinated, depressed, 

 about three in the space of 5 mm. Fenestrules oval, length 1 mm., width 

 usually about .70 mm., but sometimes the fenestrules are nearly circular ; at 

 other times the width is not more than half the length. 

 The celluliferous face has not been observed. 



This species may be distinguished from F. (P.) rigida by the coarser appear- 

 ance of the frond, and from F. (P.) distans, by the more compact growth of the 

 frond and the oval fenestrules. 



Formation and locality. Upper Helderberg group. Western New York. 



