118 
PALEONTOLOGY OF NEW YORK. 
disposed dissepiments, there being eleven branches in the same space occupied 
by seven in that species ; there are twenty cell apertures in the same space occu¬ 
pied by fourteen in that species; from F. interrupta by the more regular appear¬ 
ance of the non-cell uliferous face and by the absence of prominent, expanding 
carinee ; from F. ( Reteporina ) coalescens by the more closely arranged branches and 
dissepiments and, as compared with the branches, much wider dissepiments; from 
F. ( Reteporina ) rhombifera by the much closer disposition of the branches and 
dissepiments, and the narrower dissepiments. It is very similar on its non- 
celluliferous face to F. labiata of the Hamilton group, and from that face alone 
it is very difficult to make a satisfactory distinction ; the celluliferous face is 
very different. 
Formation and locality. Upper Helderberg group, Ontario, Canada. 
Fenestella erectipora. 
PLATE L, FIGS. 15, 17. 
Fenestella erectipora, Hall. Trans. Albany Institute, vol. x, abstract, p. 32. 1S81. 
“ “ “ Report of State Geologist for 18S5, advance sheets. Expl. pi. 50, figs. 15, 17. 
1886. 
Bryozoum infundibuliform, sometimes narrowly, at other times rapidly expand¬ 
ing. Branches moderately slender, width above bifurcation .34 to .40 mm., 
increasing to .50 mm., very gradually enlarging, sinuous or zig-zag, usually 
connected by short dissepiments, but sometimes anastomosing, angular, with 
small conical nodes opposite the dissepiments or on the anastomosed portions, 
sometimes slightly carinated; bifurcations comparatively distant. Interstices 
wider than the branches. Dissepiments strong, width .60 mm., rounded or 
angular, on a plane with the branches, three in the space of 4 mm. Fene- 
strules oval, length about .70 mm., width .45 to .60 mm. 
On the celluliferous face the branches are slightly and regularly sinuous. 
Dissepiments rounded, much depressed. Fenestrules smaller than on the 
opposite face, the length sometimes appearing less than the width of the 
dissepiment. Cell apertures in two ranges, opening directly outward, fourteen 
in the space of 5 mm., separated by one and one-half times the diameter of 
an aperture: margins distinctly elevated. Surface between the ranges of 
apertures carinated, carinee sinuous, narrow, height about .25 mm. 
