CORALS AND BRYOZOA. 37 



The specimen has a general resemblance to a Ptilodictya, but differs in 

 having intercellular vesicular tissue. 



Formation and locality. Lower Helderberg group, Clarksville, N. Y. 



STICTOPORA, Hall. 1847. 

 Stictopora papillosa. 



PLATE XUI, FIGS. \i, 13 ; a.nd PLATE XXIII A, FIG. 16. 



Stictopora papulosa. Hall. Thirty-second Rept. N. Y. State Mns. Nat. Hist., p. Kil. 1879. 



Report of State Geolosfist for 18S2. Expl. pi. 13, tigs. 12, 13. 1883. 



ZoARiUM ramose, flattened; bifurcations frequent; width of branch from 2 

 to 2.50 mm. Transverse section flattened oval ; greatest thickness 1 mm. 

 Cell apertures circular, diameter .25 mm., those nearest the margin somewhat 

 larger ; generally arranged in indistinct longitudinal rows, frequently in con- 

 tact: margins thick, strongly elevated, oblique, constricting the apertures. 



The papillose margins of the cells, and the elongate form of a transverse 

 section of a branch, are distinguishing features of this species. 



Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 



Stictopora obsoleta, n. sp. 



PLATE XXIII A, FIG. 2-3. 



ZoARiOM ramose, flattened ; bifurcations distant about 10 mm. ; width of branch 

 2 mm., increasing very slightly in width to the bifurcation. Width of the 

 non-celluliferous space at the margin .40 mm. Cell apertures ov.al, length 

 .25 mm., width .17 mm. ; disposed in longitudinal parallel rows. 



All the specimens of this species, so far observed, have been worn or macer- 

 ated, but it is easily distinguished from any other of this formation by its larger 

 size and the form and arrangement of the cell apertures. 



Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 



