CORALS AND BRYOZOA. 
137 
in two ranges, opening directly outward, slightly oblique to the axis of the 
branch, sixteen in the space of 5 mm.: margins elevated, strongly indent¬ 
ing the borders of the fenestrule. Carina nearly 1 mm. in height; the 
lower half very thin, then slightly expanding, width at the summit .20 
mm. Scalse thin, extending downward nearly to the branch, for a short 
distance oblique toward the base, then abruptly bending and continuing in 
the opposite direction, width of the outer portion about .30 mm.; eleven 
or twelve in the space of 5 mm. Interstices oval, slightly narrower than 
the scalre. 
This species may be distinguished from any other of this geological formation 
by the large size of the branches, which are rounded or battened and some¬ 
times nodose; the carinated dissepiments and the thin scaloe which at the 
summit are directed obliquely toward the base. From F. ( U .) scalaris of the 
Hamilton group, it may be distinguished as follows: the branches are less fre¬ 
quent, they are without carinse and regular rows of nodes or granules: there 
are only six branches in the same space occupied by from eight to ten in that 
species. 
Formation and locality. Upper Helderberg group, Walpole, Ontario, Canada. 
Fenestella (Unitrypa) ficticius, n. sp. 
PLATE LH, FIGS. 11-15. 
Bryozoum infundibuliform, fronds large. Branches slender, width above a 
bifurcation .25 mm., increasing to .50 mm., rounded or slightly flattened, 
sometimes carinated. Interstices of about the same width as the branches. 
Dissepiments slender, width .30 mm., flattened or gently rounded, frequently 
with a slight elevation near the upper margin, which extends upon the branches 
bordering the lower portion of the fenestrule, four in the space of 5 mm. 
'Fenestrules oval, length .80 mm., width .33 mm. 
On the celluliferous face the dissepiments are rounded, carinated, very 
much depressed. Fenestrules narrower than on the opposite face. Cell 
apertures in two ranges, opening directly outward, oblique to the axis of the 
branch, sixteen in the space of 5 mm., separated by somewhat less than the 
