CORALS AND BRYOZOA. 
77 
This species may be distinguishrd from C. ( C .) irregularis by its trilobate cell 
apertures and minute mesopores. 
The original specimen of this species was supposed to be derived from the 
Lower Helderberg group, near Clarksville, N. Y., but a more careful examina¬ 
tion has shown that it is from the shaly layers of the Upper Helderberg group 
in the central part of the State. 
Formation and locality. Upper Helderberg group, Central New York. 
LICHENALIA, Hall. 1852. 
Lichenalia lunata. 
PLATE XXXI, FIGS. 1-9. 
Fistulopora lunata, Rominger. Proc. Acad. Nat. Sci. Phila., abstract, p. 7. 1866. 
Lichenalia lunata, Hall. Trans. Albany Institute, vol. x, abstract, p. 10. 1881. 
Buscopora dentata, Ulrich. Cont. Am. Pal., vol. i, p. 22. PI. 2, figs. 5, 5a. 1886. 
Lichenalia lunata, Hall. Report of State Geologist for 1885. Expl. pi. 31, figs. 1-9. 1887. 
Zoarium consisting of lamellate expansions, free or encrusting other objects, 
thickness from 1 to 5 mm. Cells tubular, oblique to the surface; septate, 
septa frequent. Cell apertures lunate or sub-circular, width .36 mm., oblique; 
very closely and usually irregularly disposed, sometimes forming diagonally 
intersecting rows; without elevated margins. On the posterior portion of 
the aperture are two very narrow, prominent denticulations, which in the 
course of growth form two striations along the inner face of the cell wall. 
On the surface, at intervals of about 4 mm., occur maculae, which are slightly 
elevated or flat, and destitute of cell apertures. The apertures adjacent to 
these do not radiate from them and are not larger than the others. 
On some specimens where the surface has been abraded the mouths of the 
cells appear as sub-circular or circular apertures, with thin, equally elevated 
margins, distant from each other the diameter of an aperture or more. Inter¬ 
cellular structure composed of irregular vesicles or minute septate tubuli; 
both forms of structure sometimes occurring in the same frond. 
On account of the tooth-like processes and accessory cells, Mr. Ulrich has 
proposed for this species the generic designation of Buscopora. The denticula- 
