STENONEIS. 



241 



GENUS 12. STENONEIS CLEVE, 1894. 



Fig. 40. 

 Stenoneis inconspicua. 



Valve narrow, with rounded apices. Central 

 and terminal nodules very small, rounded. Raphe 

 indistinct, bordered by two strong ribs or silicious 

 costae. Transverse striae fine. Axial area indistinct. 



Only one species known, 



S. inconspicua Greg, (sub Navicula (?) Diat. 



of Clyde, p. 6, pi. 1, f. 3 ; Cleve Synop., pi. 5, f. 28*), 

 plate 28, fig. 789. 



Valve linear, frequently gibbous in the median portion, with apices 

 rounded, obtuse ; nodules small, the terminal ones somewhat distant from the 

 apices. Raphe bordered by two strong silicious costae. Striae 26 to 1 c.d.m., 

 perpendicular to the raphe throughout, absent at the median portion where 

 there is a broad hyaline transverse band. Length. 5 c.d.m. Breadth, 75 

 c.d.m. 



Marine. North Sea (Scotland, Greg., Bahusie, Cleve.). 



y 



GENUS 13. CISTULA CLEVE, 1894. 



Valve rectangular, broad. Central nodule 

 very small. Raphe between two strong 

 silicious costae. Striae radiant, slightly inter- 

 rupted by several hyaline 

 bands. 



Only one species known. 



longitudinal 



Fig. 41. Cistula Lorenziana, 



C. Lorenziana Grun. (sub Navicula in Verh., i860, p. 547, pi. 3, 

 f. 3* ; Cleve Syn., pi. 1, f. 31), plate 28, fig. 790. 



Valve rectangular, sometimes somewhat gibbous in the middle and at the 

 apices. Striae gently radiant, about 17 in 1 c.d.m., composed of elongated 



R 



