CORALS AND BRYOZOA. Ill 



dissepiments are opposite each other, the branch midway between them is 

 elevated ; bifurcations distant. Dissepiments, as compared with the branches, 

 strong, width from .30 to .35 mm., rounded, occasionally with one or more 

 nodes, on the same plane or elevated slightly above the branches, six in the 

 space of 5 mm. Fenestrules oval, length .45 or .50 mm., width .25 mm. 



On the celluliferous face the dissepiments are rounded, much depressed. 

 Fenestrules narrower than on the opposite face. Cell apertures in two ranges, 

 twenty-two in the space of 5 mm., separated by less than the diameter of an 

 aperture : margins thin, slightly elevated. Surface between rows of aper- 

 tures carinated ; carinae strong, slightly elevated, with small, closely disposed 

 nodes on the summit. 



The non-celluliferous face resembles F. stellata but the branches of the 

 celluliferous face are never channeled and do not have prominent nodes. 



This species may be distinguished from F. serrata by its generally coarser 

 appearance, the greater distance of the dissepiments, there being respectively 

 six and nine dissepiments in the same space. 



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



Fenestella depressa. 



PLATE XLV, FIGS. 16, 17. 



Fenestella depretsa. Hall. Trans. Albany Institute, vol. x. abstract, p. 30. 1881. 



" " " Report of State Geologist for 1883, advance sheets. Expl. pi. 45, figs. 16, 17. 



1886. 



Bryozoum infundibuliform. Branches slender, width above a bifurcation .30 

 mm., increasing to .45 mm., rounded, finely striated. Interstices narrower 

 than the branches. Dissepiments very slender, width .18 mm., rounded, 

 much depressed, nine in the space of 5 mm. Fenestrules oval or sub-quad- 

 rangular, length .40 ram., width about .20 mm. 



On the celluliferous face the dissepiments are rounded, much depressed. 

 Fenestrules having the same appearance as on the opposite face. Cell aper- 

 tures in two ranges, opening directly outward, twenty-six in the space of 5 

 mm., separated by less than the diameter of an aperture : margins elevated. 



