194 PALEONTOLOGY OF NEW YORK. 



very infrequent Cell apertures oval, length .25 mm., width two-thirds the 

 length, disposed in longitudinal, sometimes twisted rows, often alternating and 

 forming oblique transverse rows. The apertures near the basal portion of 

 the frond are distant from each other about the width of an aperture, above 

 this they are more closely disposed ; the inter-apertural surface is fiat, striated, 

 striae granulose. On some portions of the frond the apertures are nearly 

 in contact, the surface between them slightly elevated, angular and gran- 

 ulose, inclosing the apertures in polygonal areas. 



This species may be distinguished from Nemaiaxis simplex by its larger cell 

 apertures, their less distinct arrangement in longitudinal rows, and the more 

 prominent granulse : from Trematopora {Orthopora) orbipora by the more oval 

 apertures, more distinct arrangement in longitudinal rows and the granulose 

 striations. 



Formation and locality. Hamilton group, Darien Centre, Erie county, N. Y. 



Bactjiopoka curvata, n, sp. 



I'LATK UCVI, FIGS. U-16. 



The specimens observed consist of simple stipes, but it is probable that larger 

 specimens would show a ramose character: diameter .75 mm., base obtusely 

 pointed. Cell apertures oval, length .25 mm., width one-half the length, 

 disposed in longitudinal parallel rows, distant the width of an aperture. Six 

 or seven rows on a branch, separated by comparatively prominent nodose or 

 granulose ridges ; nodes small, one or two ranges on each ridge, the other 

 portions of the surface similarly ornamented. 



This species is peculiar and will be readily distinguished from any species at 

 present known in this geological formation. 



Formation and locality. Hamilton group, Can.andaigua lake, N. Y, 



