CORALS AND BRYOZOA. 227 



the superimposition of successive layers of growth, while in this species the 

 cell tubes continue from the base to the surface without interruption; the 

 apertures are usually oval or sub-trilobate, and the mesopores are larger and 

 more variable in shape. 



Formation and locality. Shales of the Hamilton group, York, Livingston 

 county, N. Y. 



FiSTULIPORA CONSTRICTA. 



»0T FIGDKED. 



LieheTUilia coTistricta, Hall. Trans. Albany Institute, vol. x, p. 183. 1881. 

 " " " Report of State Geologist for 1883, p. 36. 1884. 



ZoARiUM consisting of explanate fronds, encrusting other bodies, generally 

 Cyathophylloid corals and Crinoid columns, or of masses formed by the accre- 

 tion of successive layers of growth. Cells tubular cylindrical, rectangular 

 to the surface, non-septate ; walls thin. Interapertural space vesiculose, near 

 the base the vesicles are comparatively large and irregularly disposed, being 

 much smaller and more regularly superimposed above, frequently appear- 

 ing like septate tubuli, from sixty to one hundred septa in the space 

 of 5 mm., near the surfjice almost in contact ; the vesicles are more numer- 

 ous than in any other species observed. Cell apertures circular, diameter 

 about .25 mm., disposed in irregular intersecting lines, usually distant about 

 two- thirds the diameter of an aperture. Peristomes thin, slightly elevated, 

 sind having on one side two minute denticulations, which in the course of 

 growth form two parallel striations along the inner face of the cell walls. 

 Interapertural surface elevated above the peristomes, angular or rounded, 

 and occupied by minute, very shallow pits, which frequently appear oval or 

 circular, generally one or two series between adjacent apertures, sometimes 

 three, especially on or near the monticules. 



When the frond is a little worn or macerated the interapertural surface is 

 flattened and the pits have the usual angular form, diameter about .10 mm., 

 sometimes even less. Surface marked by obtusely conical monticules, the 

 centers of which are distant from each other about 5 mm., with a central 



