CLIMACOSPHENIA. 345 



Valves very narrow, abruptly attenuate near the inferior third. Pseudo- 

 raphe indefinite. Stride very fine, about 30 or 31 in 1 c.d.m. near the middle of 

 the valve. Girdle face very broad, abruptly truncate at the base, rounded at 

 the summit ; septa gently arcuate. 



Marine. North Sea ? 



L. communis (Heib. ?) Grun. (in h.v.h. Atl., pi. 48, f. 8, 

 9*), plate 31, fig. 857. 



Valves obovate, pyriform, short, with inferior apex subacute ; pseudo-raphe 

 indefinite, striae fine, 22 to 24 in 1 c.d.m. at the middle of the valve. Girdle 

 face very broad, with septa strongly and abruptly bent towards the superior 

 third. 



Marine. On all the coasts of Europe. 



L. nubecula (Kutz.) Grun. (Kaspisch. Meere, p. 123; H.V.H. 



Atl, pi. 48, f. 18*), plate 31, fig. 858. 



Valve very gently attenuate ; striae very fine, about 31 in 1 c.d.m. Girdle 

 face rather narrow, with septa slightly arcuate. 



Marine. North Sea? Coasts of France (Atlantic Ocean at Granville, De Breb. ). 



L. tenuis (Kutz.) Grun. (in Hedw, 1S67, p. 35 ; h.v.h. Atl., pi. 



48, f. 21*; Podosphenia gracilis W. Sm. !), plate 31, fig. 859. 



Valve long and narrow, very slightly attenuate, striae fine, about 16 in 1 

 c.d.m. Girdle face long, very narrowly cuneate, with septa rather strongly 

 bent near the superior apex of the frustule. 



Marine. North Sea. England (Jersey, W. Sm. !), Norway, etc. 



GENUS 62. CLIMACOSPHENIA EHR., 1843. 



Valve oboval, lanceolate or subclavate, linear, very finely striated 

 transversely, showing neither pseudo-raphe nor nodules, leaving the 

 scalariform openings of the underlying septa visible through the 

 valves. Frustules cuneate, showing the apices of the transverse costae 

 and a connecting membrane, with robust moniliform striae. 



