24 
PALEONTOLOGY OF NEW YORK. 
length from .33 to .50 mm., width from one-half to three-fourths the length; 
closely and irregularly disposed. Anterior margin thin, slightly elevated, 
gradually growing more prominent, and at the posterior end strongly 
elevated, oblique, denticulated, constricting that portion of the aperture. 
Mesopores variable in size, some having a diameter of only .15 mm., while 
others are nearly as large at the cell apertures; margins very thin; height 
equal to that of the anterior margin of the cell aperture. 
I had formerly considered this species a form of Fistulipora parasitica , but its 
apparent parasitic character is due to the flattening of the larger branches and 
their attachment to other bodies. 
Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 
Callotrypa, n. s. g. 
The species resemble Callopora in their general characters, but differ in 
having a solid intercellular space, or which is sometimes occupied by minute 
tubuli, destitute of septa; while in that genus the intercellular space is vesicular 
or occupied by septate tubuli. 
Callopora (Callotrypa) macropora. 
PLATE XI, FIGS. 25-29; AND PLATE XXIII, FIGS. 15-19. 
Callopora macropora, Hall. Twenty-sixth Rept. N. Y. State Mus. Nat. Hist., p. 101. 1874. 
“ “ “ Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 152. 1879. 
In part Callopora macropora, Hall. Report of State Geologist for 1882. Expl. pi. 11, fig-s. 23-29. 18S3. 
Zoarium ramose, solid, diameter of branches from 1 to 2 mm.; bifurcations fre¬ 
quent; branches diverging from forty-five to ninety degrees. Cells tubular, 
arising from the center of the branch and regularly curving to the surface, 
increasing by interstitial addition ; in contact for the greater portion of their 
length. Walls thin, becoming thicker near the surface and slightly constrict¬ 
ing the cell tube. Apertures oval or polygonal from mutual pressure, length 
on different specimens from .33 to .50 mm., width from one-half to two-thirds 
the length; irregularly disposed, generally some portion of each aperture in 
