134 
PALEONTOLOGY OF NEW YORK. 
This species may be distinguished from F. ( U .) acauJis, by the more slender 
and closely disposed dissepiments, which are slightly depressed below the plane 
of the branches; from F. (77.) stipata, by the more slender and more rapidly 
enlarging branches, the narrower and more frequent dissepiments, there 
being eleven in the same space occupied by seven in that species, and by the 
much more numerous scalae; from F. (77) tegulata by the much more closely 
disposed scalae. 
Formation and locality. Upper Helderberg group, Walpole, Ontario, Canada. 
Fenestella (Unitrypa) stipata. 
PLATE LI, FIGS. 7-14. 
Fenestella (Hemitrypa) stipata. Hall. Trans. Albany Institute, vol. x, abstract, p. 34. 1881. 
“ ( Unitrypa ) “ “ Report of State Geologist for 1885, advance sheets. Expl. pi. 51, 
figs. 7-14. 1886. 
Bryozoum infundibuliform, compact. Branches slender, width above a bifurca¬ 
tion .25 mm., increasing to .50 mm., sometimes straight, but generally sinuous 
or zig-zag, connected by very short dissepiments, angular, carinated; carina 
slight, sometimes granulose or nodose; on some fronds the carinse of adjacent 
branches unite on the dissepiments, having a small, conical node at the junc¬ 
tion. Interstices usually a little narrower than the branches. Dissepiments 
strong, width generally from .35 to .40 mm., angular, carinated; carinse similar 
to those of the branches and connecting with them, six in the space of 5 mm., 
on the same plane or elevated above the branches, very frequently extending 
across them, coalescing with adjacent dissepiments, forming irregular, con¬ 
tinuous elevations, which are more conspicuous than the branches, and give 
to the frond an irregular appearance. Fenestrules oval, length generally 
from .45 to .50 mm., width .33 mm.; on one frond length .25 mm., width 
.20 to .25 mm. 
On the celluliferous face the dissepiments are rounded, much depressed. 
Fenestrules narrower than on the opposite face, length more than twice the 
width. Cell apertures in two ranges, opening nearly directly outward, eight¬ 
een in the space of 5 mm., closely disposed, nearly or quite in contact: mar¬ 
gins elevated, indenting the borders of the fenestrules. Surface between 
