108 PALEONTOLOGY OF NEW YORK. 



On the celluliferous face the dissepiments are rounded, depressed. Fenes- 

 trules narrower than on the opposite face. Cell apertures large, in two 

 ranges, opening directly outward, twenty-four in the space of 5 mm., closely 

 disposed, nearly or quite in contact: margins strong, elevated, indenting 

 the border of the fenestrule. Surface carinated; carinae broad, slightly 

 elevated, nodose ; nodes strong, about equal in number to the cell apertures. 



This species may be distinguished by its delicate appearance and curved 

 dissepiments. 



Formation and locality. Upper Helderberg group, Falls of the Ohio river. 



Fenestella confertipora, n. sp. 



PLATE XLVI, FIGS. 7-11 AND 17-21. 



Brtozoum infundibuliform. Branches of two kinds, usually slender, having 

 a width above a bifurcation of .20 mm., increasing to .35 or .40 mm., but 

 others frequently occur having sometimes twice the diameter of the ordi- 

 nary branches; the slender branches sometimes proceed laterally from the 

 stronger ones. The larger branches occur most frequently on the basal 

 portion of the frond, becoming less frequent above. Interstices of the same 

 width as the branches or slightly n.arrower. Dissepiments slender, width 

 from .20 to .25 mm., wider near the base of the frond than above, rounded, 

 smooth, very slightly expanding, on a plane with the branches, nine in the 

 space of 5 mm. Fenestrules oval or sub-quadrangular, length from .30 to 

 .35 mm., width from .20 to .25 mm. 



On the celluliferous face the dissepiments are sub-angular and depressed. 

 Fenestrules narrower than on the opposite face, length more than twice the 

 width. Cell apertures large, in two ranges, opening directly outward, 

 twenty-four in the space of 5 mm., in contact ; margins elevated, strongly 

 indenting the borders of the fenestrules. Surface between the ranges of 

 apertures carinated ; carinae broad, slightly elevated, nodose ; nodes small. 



This species may be distinguished by the frequent large branches, sometimes 



