88 PALEONTOLOGY OF NEW YORK. 



.25 mm., width two-thirds the length ; irregularly disposed, frequently in 

 contact. Peristomes strong, equally elevated, sometimes with one or two 

 comparatively strong nodes or spinules. Mesopores minute, usually only one 

 series between adjacent apertures ; margins the same height as those of the 

 peristomes. Intercellular space vesiculose. 



This species may be distinguished from F. digita, of the Hamilton group, by 

 its manner of growth, that species being always more or less digitate, the less 

 closely disposed apertures and the absence of numerous spinules ; from F. 

 striata, it diflfers in its much smaller mesopores, those of that species some- 

 times obscuring the apertures ; from F. multiaculeata, it differs in having the 

 apertures smaller, more broadly oval, and without the numerous spinules 

 characteristic of that species. 



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



COSCINIUM, Keyserling. 1846. 



COSCINIUM STRIATUROM. 



PLATE XXXni, FIGS. 20, 21. 



Clathropara striatura. Hall. Reiwrt of SUte Geologist for 18S2. Expl. pi. 26, figs. 20, 21. 1883. 



ZoARiDM consisting of lamellate expansions, celluliferous on each side; per- 

 forated at regular intervals by oval fenestrules. Cell apertures oblique, sub- 

 triangular, diameter .18 mm.; closely disposed, frequently alternating and 

 imbricating: anterior portion of the peristome not elevated; posterior portion 

 strongly elevated, projecting over and partially concealing the opening, and 

 having two slight denticulations. Fenestrules oval, length about 2 mm., 

 usually occurring at intervals of about 4 mm. ; disposed in diagonally inter- 

 secting rows. There is a space around each fenestrule destitute of aper- 

 tures, much wider at the lower part of the fenestrule than above, and with 

 low, broad ridges. The general direction of the cells is not interrupted by 

 the fenestrules. 

 This species is easily distinguished from Coscinotrypa carinata by the absence 



of lateral growths, and the general direction of the cells not being interrupted 



by the fenestrules. 



Formation and locality. Upper Helderberg group, Stafford, N. Y. 



