FOSSILS OF THE CLINTON GROUP. 113 



divisions of the stipe are curved outward at the bifurcations, giving a 

 much greater angle than in the forms above described. 



Surface of the bryozoum cellulose, the cells arranged in vertical lines 

 parallel to the direction of the stipe, and also forming horizontal lines 

 across the stipe. Cell apertures oval, their distances from each other 

 equal to the diameter of the aperture in the vertioal lines, and still 

 greater in the horizontal lines. The substance of the stipe, between the 

 ranges of pores, is marked by two additional microscopic pores at the 

 base of each cell aperture, or midway betweeh the contiguous cells. 

 This feature is one not before observed in any species of the genus, and 

 will serve to distinguish this species from any heretofore described. 



Formation and locality : In the Clinton group, at the quarries at the Soldiers' Home, 

 near Dayton, Ohio. Collection of Prof. Edward Orton. 



Genus CLATHROrORA, Hall, 1852. 



(Pal. N. Y., Vol. I.) 



Clatheopoea Clintonensis (n. sp.). 



Plate 5, fig. 7. 



Bryozoum frondose, expanded, reticulate, with large oval openings 

 passing entirely through the frond, forming the branches or divisions of 

 the reticulations ; substance of the branches between the openings about 

 equal in breadth to that of the opening, or narrower — seldom wider. 

 Surface of the frond cellulose ; cells arranged in oblique lines, crossing 

 the branches diagonally ; from six to twelve of the cells can be counted' 

 in the width of the branch ; apertures rhomboid oval. 



All the examples examined have been separated through the center, 

 on the plane of the frond, showing that they have a central dividing 

 partition, the fronds being cellulose on both surfaces ; and over the entire 

 surfaces presented to view we see only the inner face, or base of the cells. 

 The form and character of the cell aperture is taken from small spots 

 where the entire substance of th« bryozoum has been removed, leaving 

 an imprint on the surface of the stone. The species differs from 0. fron- 

 dosa, Hall (Pal. N. Y., Vol. II., p. 160, pi. 40&, fig. 5), and also from 0. flabel- 

 lata, Hall (Fost. and Whit., Lake Sup., p. 207, pi. 24, fig. 2), in the nar- 

 rower branches and the smaller number of cells in their width. The 



