CORALS AND BRYOZOA. 
25 
contact with adjacent apertures: margins distinctly and equally elevated, 
occasionally nodose. Mesopores minute: margins of the same height as 
those of the apertures. No internal vesicular structure visible. 
Formation and localities. In the shaly limestone of the Lower Helderberg 
group, at Catskill, Greene county; near Clarksville, and at Schoharie, N. Y. 
Callopora (Callotrypa) macropora, var. slgnata. 
PLATE XI, PIUS. 30, 31. 
Trematopora slgnata. Hall. Twenty-sixth Rept. N. Y. State Mas. Nat. Hist., p. 104. 1874. 
Callopora macropora, var. slgnata. Hall. Thirty-second Rept. N. Y'. State Mus. Nat. Hist., p. 153. 1879. 
“ “ “ “ Report of State Geologist for 1882. Expl. pi. II, figs. 30, 31. 
1883. 
This variety differs from the usual form of C. macropora in the more distinctly 
polygonal cell apertures, and in having but very few intercellular pits. 
Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 
Callopora (Callotrypa) heteropora. 
PLATE XI, PIGS. 32-31 ; PLATE XIII, PIGS. 5-8; AND PLATE XXIII, PIG. 3. 
Callopora heteropora, Hall. Twenty-sixth Rept. N. Y. State Mus. Nat. Hist., p. 102. 1874. 
“ “ “ Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 153. 1879. 
“ “ “ Report of State Geologist for 1882. Expl. pi. 11, figs. 32-34; pi. 13, figs. 5-8. 
1883. 
Zoarium ramose, solid, diameter of branches from 1 to 1.50 mm.; bifurcations 
distant; branches diverging at an angle of forty-five degrees. Cells tubular, 
arising from the center of the branch and very gradually diverging till within 
a short distance of the surface, when they turn abruptly outward; at this point 
the walls, previously very thin, become thicker, slightly constricting the cell. 
For the greater portion of their length the cells are in contact and sub- 
angular from mutual pressure. Apertures oval, length .20 mm., width about 
two-thirds the length; irregularly disposed: margins equally elevated. 
Mesopores minute, elongate, angular, so arranged that their margins often 
