62 
PALAEONTOLOGY OF NEW YORK. 
This species is characterized by the form of the branches, which are rhom- 
boidal in transverse section for some distance above a bifurcation and square 
in the wider portions. It resembles F. paxillata, but has somewhat stronger 
branches, and is more lax in its manner of growth. 
Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 
Fenestella (Polypora) Lil^a. 
PLATE XVIII, FIGS. 19-22. 
Polypora Lilia, Hall. Twenty-sixth Rept. N. Y. State Mus. Nat. Hist.., p. 96. 1874. 
Fenestella (Polypora) Lmpa, Hall. Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 165. 1879. 
“ " “ “ Report of State Geologist for 1882. Expl. pi. 18, figs. 19, 20. 1883. 
Retepora, n sp., Hall. Report of State Geologist for 1882. Expl. pi. 18, figs. 21, 22. 1883. 
Bryozoum probably infundibuliform, growing from a very thin spreading 
radicle, which merges into a slender pedicel above having a diameter of 
1 mm. Branches moderately strong, rounded on the non-celluliferous face 
and marked by obscure striae. Bifurcations frequent. Dissepiments strong, 
expanding at their junction with the branches; four in the space of 5 mm. 
Fenestrules oval, width generally one-half the length. 
On the celluliferous face the branches are rounded or flattened, and the 
dissepiments rounded and depressed. Fenestrules of the same appearance 
as on the opposite face. Cell apertures in from two to four ranges, the 
marginal ranges opening laterally; twenty in the space of 5 mm. When 
the specimen is worn or macerated the cells are large, oval and in contact, 
and without a careful examination this feature might readily be mistaken 
for the normal condition of the fossil. 
Width of branches just above the bifurcation .20 mm., increasing to 
.70 mm. ; diameter of dissepiments .25 mm. 
Formation and localities. Lower Helderberg group, Schoharie, and near 
Clarksville, N. Y. 
