222 
PALAEONTOLOGY OF NEW YORK. 
apertures; from all other species, at present known in this formation, it is 
distinguished by its smaller cell apertures and extremely minute mesopores. 
Formation and, locality. Shales of the Hamilton group, two and a half miles 
east of Alden station, Erie county, N. Y. 
Fistulipora trifaria, n. sp. 
NOT FIGURED. 
Zoarium consisting of free or incrusting explanate fronds; greatest observed 
thickness about 1 mm. Cells tubular, cylindrical, rectangular to the surface; 
septa very thin and infrequent. Intercellular space vesiculose; near the base 
the vesicles are large and very irregularly disposed; they are somewhat 
more regularly superimposed above, but never having the appearance of 
septate tubuli in the specimens observed. Cell apertures trilobate, length 
about .30 mm., width slightly less, irregularly disposed, sometimes in con¬ 
tact, at other times distant the diameter of an aperture or even more. 
Peristomes thin, equally elevated, apparently not denticulated, sometimes 
having minute nodules or spinules. Mesopores variable in size, frequently 
nearly as large as the cell apertures. Surface marked by elongate, slightly 
depressed maculae, disposed at irregular intervals. 
The cell apertures of this species most nearly resemble those of Lichenalia 
vesiculata, but it is easily distinguished by the presence of mesopores. 
Formation and locality. Hamilton group, Fallbrook, four miles east of Canan¬ 
daigua lake, N. Y. 
Fistulipora triangularis. 
NOT FIGURED. 
Thallostigma triangularis, Hall. Trans. Albany Institute, vol. x, p. 187. 1881. 
“ “ “ Report of State Geologist for 1883, p. 32. 1884. 
Zoarium consisting of free or incrusting lamellate expansions, or of masses 
formed by the accretion of successive layers of growth; thickness of a 
single layer 1 mm.; under surface a thin epitheca, concentrically wrinkled 
and striated. Cells tubular, cylindrical, oblique. Intercellular tissue vesi¬ 
culose ; near the base the vesicles are very irregularly disposed, and 
