Fenestella (Unitkypa) transversa. 



Fm. 9. 



Fenestella (Unitrypa) transversa, Hall. Pal. N. Y., Vol. VI, page 132 (not 



figured). 



Fig. 9. An enlargement from the non-celluliferous face of a frond, show- 

 ing the prominently carinate dissepiments which extend over 

 the branches on the right hand portion of the figure, and becom- 

 ing depressed and merged on the left side, 



Fenestella varia, n. sp. 

 Figs. 10-12. 

 Fig. 10. An enlargement of two branches with the connecting dissepi- 

 ments, showing the arrangement of cell apertures with thin 

 margins. On the left side the central range of apertures is 

 interrupted, and a row of pustules continued in the same line. 

 Fig. 11. xi lateral view of a branch with transverse sections of the dissepi- 

 ments, and showing the projecting cell margins. 18 x. 

 Fig. 12. A transverse section of branches showing those with two and 

 those with three ranges of cells. 

 This species resembles F. arta, but is a smaller form. 

 Lower Helderberg group. Clarkesville, N. Y. 



