CORALS AND BRYOZOA. 
65 
twenty in the space of 5 mm. ; distant less than the diameter of an 
aperture: margins strong, elevated, those of the marginal ranges indenting 
the borders of the fenestrules and giving to them a crenulated appearance. 
Width of branches .40 mm., increasing to .75 mm. ; diameter of dissepi¬ 
ments .40 mm.; length of fenestrules about .40 mm. 
This species, in some respects, closely resembles F. (P.) Arta, to which it was 
formerly referred, but it has a more robust appearance, the cell apertures are 
more closely disposed, and the ranges are not separated by a carina. 
Formation and locality. In the shaly limestone of the lower Helderberg 
group, on Catskill creek, Greene county, N. Y. 
Fenestella (Polypora) paxillata. 
PLATE XVIII, FIGS. 10-12. 
Fenestella paxillata, Hall. Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 164. 1879. 
“ papillata (in error), Hall. Report of State Geologist for 1882. Exp), pi. 18, fig-s. 10-12. 1883. 
Bryozoum observed only in fragments, the form is, therefore, not definitely 
known. On the non-celluliferous face the branches are slender, at first 
rounded, becoming flattened and concave for a short distance before bifurcat¬ 
ing, and marked by fine strife. Bifurcations distant. Dissepiments moder¬ 
ately strong, rounded, slightly depressed below the plane of the branches. 
Fenestrules sub-quadrangular; width from one-half to one-third the length. 
On the celluliferous face the branches are rounded, the dissepiments 
sub-angular and very much depressed. The fenestrules appear of the same 
form as on the opposite face. Cell apertures minute, circular; fourteen in 
the space of 5 mm.; distant about the diameter of an aperture; disposed in 
from two to four ranges; two ranges occur only for a short distance above 
the bifurcation, while the greater portion of the branch is occupied by three 
ranges. The central range or ranges open directly outward, the outer 
ranges open laterally. 
Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 
