226 
PALAEONTOLOGY OF NEW YORK. 
its manner of growth, the larger cell apertures, the much more prominent 
peristomes, and the absence of maculae destitute of cell apertures. 
Formation and locality. Hamilton group, York, Livingston county, N. Y. 
Fistulipora iiemispherica. 
PLATE LVII, FIGS. 8-11. 
Cnllopora Iiemispherica, Hall. Trans. Albany Institute, vol. x, p. 183. 1881. 
“ “ *• Report of State Geologist for 1883^ p. 17. 1884. 
Zoarium consisting of hemispherical masses, the base attached to foreign 
bodies, usually Cyathophylloid corals; under surface consisting of a 
thin concentrically wrinkled epitheca. The largest specimen observed 
has a diameter of 25 mm. and a thickness of 12 mm. Cells tubular 
cylindrical; at the center they are at right angles to the epitheca, 
becoming more and more oblique as they approach the margin; non- 
septate; walls very thin, smooth. Intercellular space vesiculose, vesicles 
large and irregularly disposed near the base, regularly superimposed 
above, often appearing as septate tubuli, or as septa dividing the space 
between the cell tubes, the latter condition closely resembling a septate cell 
tube. Cell apertures oval, circular or obscurely trilobate, sometimes polygo¬ 
nal from mutual pressure, diameter .50 mm., closely and irregularly disposed, 
frequently in contact. Peristomes moderately strong, slightly elevated when 
the frond is well preserved; when worn or macerated they are much 
more prominent; many have a spine-like projection from .20 to .25 mm. in 
height, others, apparently equally well preserved, are smooth. Interaper- 
tural space occupied by angular pits, varying greatly in size and shape 
according to the position of the cell apertures; when the frond is well pre¬ 
served they are often obsolete, or their margins appear as obscure ridges on 
the surface; when slightly worn or macerated they are very conspicuous. 
Surface marked by obscure monticules. 
In shape this species resembles F. spheroidea and F. milinea, but the mode of 
growth is different. The massive forms of those species being composed of 
