CORALS AND BRYOZOA. 93 



Stictopora ovatipora. 



PLATE XXVn, FIGS. 12-19 ; and PLATE XXVni, FIGS. -23, 23a. 



Stictopora ovatipora. Hall. Trans. Albany Institute, vol. x, abstract, p. 14. 1881. 



Report of State Geologist for 1882. Expl. lA. 25, figs. 23, 23 A. 1883. 



Report of State Geologist for 1885, advance sheets. Expl. pi. 27, figs. 12-19. 1886. 



ZoARiUM consisting of a dichotoinously branching, flattened stipe ; transverse 

 section broadly lenticular ; width of branches from 2 to 3 mm., margins 

 essentially parallel ; greatest thickness less than 1 mm. Cell apertures oval, 

 length about .25 mm , width from one-half to two-thirds the length ; mar- 

 ginal apertures larger than the others, and more nearly circular ; disposed in 

 longitudinal rows, increasing by interstitial addition. Rows separated by 

 prominent ridges. Peristomes strong, distinctly and equally elevated, having 

 two slight denticulations, which are invariably situated on the outer margin 

 of the aperture. Intercellular space irregularly vesicular. 



This species closely resembles S. Gilberti, but may be distinguished by its 

 n.'irrow branches with essentially parallel margins, which give to the frond a 

 somewhat rigid appearance. 



Formation and locality. Upper Helderberg group. Falls of the Ohio river. 



Stictopora vermicula. 



PLATE XXVII, FIGS. 2-4. 



Stictopora venaiciUa, Hall. Report of State Geologfist for 1885, advance sheets. Expl. pi. 27, figs. 2-4. 



1886. 



ZoARiDM consisting of a dichotoinously branching and flattened stipe, of irregular 

 appearance ; transverse section sub-lenticular, abruptly narrowing and very 

 thin near the margins ; width of branches from 2.50 to 3 mm., margins 

 slightly divergent ; non-celluliferous space comparatively wide, flat; greatest 

 thickness about .80 mm. ; bifurcations frequent. Cells tubular, length about 

 .80 mm., for a little more than one-half their length essentially parallel with 

 the mesotheca, then abruptly turning outward. Cell apertures broadly oval 

 or circular, frequently pustuliform, diameter from .25 to .30 mm., the mar- 

 ginal ones larger than the others; disposed in indistinct longitudinal and 



