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. 



PLATK XXXI, FIGS. 1-9. 



FUttdtrpora lunnta, Romihokb. Pi-oc. Acad. Nat. Sci. Phila., abstract, p. 7. 1866. 

 Lichenalia lunata. Hall. Trans. Albany Institute, vol. x, absti'act, p. 10. 1881. 

 Bwicopora daitata, Ulbich. Cont. Am. Pal., vol. i, p. 22. PI. 2, figs. 5, 5a. 1886. 

 Lichenalia lunata. Hall. Rfimrt 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 clo.sely 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- 



