CORALS AND RRYOZOA. 
119 
This species most nearly resembles F. ( Reteporina ) rhombifera and F. granifera ; 
from the first it may be distinguished as follows: the branches are not so 
decidedly anastomosing, the dissepiments are narrower and more closely dis¬ 
posed, there being eight in the same space occupied by five in that species; from 
F. granifera, by the branches being generally more angular, with small conical 
nodes, and without the line of granules along the middle of the branch, charac¬ 
teristic of that species; the carina does not expand, is slightly elevated and has 
no nodes on the sides. 
Formation and locality. Upper Helderberg group, near Buffalo, N. Y. 
Fenestella cultrata. 
PLATE L, FIGS. 1-5. 
Fenestella cultrata, Hall. Trans. Albany Institute, vol. x, abstract, p. 29. 18S1. 
“ “ “ Report of State Geologist for 1885, advance sheets. Expl. pi. 50, figs. 
1-5. 1886. 
Bryozoum infundibuliform. Branches moderately slender, width above a bifur¬ 
cation .35 mm., increasing to .75 mm., rounded or sub-angular, becoming 
flattened for a short distance before bifurcation. Interstices generally wider 
than the branches. Dissepiments slender, width from .25 to .35 mm., rounded, 
on a plane with the branches and frequently oblique to them; usually about 
two in the space of 5 mm. Fenestrules sub-quadrangular, length from 1.75 
to 2.25 mm., width from .40 to .80 mm. 
On the celluliferous face the dissepiments are rounded, much depressed. 
Fenestrules of the same appearance as on the opposite face. Cell apertures 
in two ranges, opening laterally, eighteen in the space of 5 mm., closely dis¬ 
posed, frequently in contact. Surface between ranges of apertures carinated; 
carinse strong, angular, height .30 mm. 
This species most nearly resembles F. biserrulata, but is more lax in appear¬ 
ance, the fenestrules are larger, the cell apertures open laterally, and the carina 
does not expand and has no nodes on the side. 
Formation and locality. Upper Helderberg group, Falls of the Ohio river. 
