26 
PALEONTOLOGY OF NEW YORK. 
resemble fine striations. The margins of the apertures and intermediate pits 
are frequently spinulose. 
Formation and locality. In the slialy limestone of the Lower Helderberg 
group, near Clarksville, Albany county, N. Y. 
Callopora (Callotrypa) unispina. 
PLATE XI, FIGS 35-37. 
Callopora unispina, Hall. Twenty-sixth Kept. N. Y. State Mas. Nat. Hist., p. 102. 1874. 
“ “ “ Thirty-second Rept. N. Y. State Mus. Nat. Hist., p- 153. 1879. 
In part Callopora unispina, Hall. Report of State Geologist for 1882. Expl. pi. 11, tigs. 35-41. 1SS3. 
Zoarium ramose, solid, diameter from 1.50 to 2 mm. Cells tubular, arising 
from the center of the branch and regularly curving to the surface. Aper¬ 
tures broadly oval, length .17 mm., width about three-fourths the length; 
occasionally circular, closely and irregularly disposed : margins moderately 
strong, equally elevated. At the base of each aperture is a, comparatively, 
very prominent spinule. Mesopores minute, elongate, angular, so disposed 
that the margins give to the surface a finely striated appearance. No vesi¬ 
cular intercellular space. 
This species, when well preserved, will be easily recognized by the prominent 
spinule at the base of each aperture; when worn or macerated it very closely 
resembles C. heteropora. 
Formation and localities. In the slialy limestone of the Lower Helderberg 
group, on Catskill creek, Greene county, and near Clarksville, Albany county, 
N. Y. 
Callopora (Callotrypa) striata, n. sp. 
PLATE XI, FIGS. 38-41 ; AND PLATE XXIII, FIGS. 13, 14. 
In part Callopora unispina. Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 153. 1S80. 
“ “ “ Report of State Geologist for 1882. Expl. pi. 11, tigs. 35-41. 18S3. 
Zoarium ramose, solid, diameter of branches 1 mm.; bifurcations infrequent. 
Cell apertures oval, length .33 mm., width about one-half the length; 
irregularly disposed, sometimes in contact; at other times distant .33 mm. 
or more: margins moderately strong, distinctly and equally elevated. At 
