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 HEMISPHERICA. 



PLATE LVII, FIGS. 8-n. 



Cnllopora hemispherica. Hall. Trans. Albany Institute, vol. x, p. 183. 1881. 

 " " '• Reiwrt of SUte Geologist for 1883, p. 17. 1884. 



ZoARiTJM 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. unilinea, but the mode of 

 growth is different. The massive forms of those species being composed of 



