108 
PALAEONTOLOGY 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. 
Bryozoum 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 narrower. 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 ; carinm broad, slightly elevated, nodose ; nodes small. 
This species may be distinguished by the frequent large branches, sometimes 
