184 NAVICULA. 



cave sides, showing a smooth space at the apices. Connecting membrane 

 smooth. Breadth of girdle face, 3*5 c.d.m. 

 Marine North Sea (?), Baltic Sea, etc. 



N. inflexa (Greg.) Ralfs. (in Pritch. Inf., p. 905 ; A. Schmidt's 



Atl., pi. 46, f- 69-7*), plate 25, fig. 713. 



Very narrowly lanceolate, with apices sub-acute, inflexed. Striae, 10 in 



1 c.d.m., distinctly punctate, radiate, reaching almost to the raphe, much 



shortened near the central nodule. Length of valve, about 3 to 5 c.d.m- 



Breadth, about 75 c.d.m. 



Marine Scotland (Greg.), England (Donk.), Ireland (O'Meara). 



N. fortis Greg. (T.M.S., 1856, iv.,p. 46, pi. 5, f. 19, svb Pinnularia ; 



in Ad. Sch. Atl., pi. 46, f. 27*), plate 25, fig. 715. 



Valves oblong, with apices obtuse, rounded. Striae very robust, about 5 in 

 1 c.d.m., not reaching to the raphe, gently radiate in the median portion ; 

 almost perpendicular at raphe, near the apices, leaving a hyaline area round 

 the central nodule. Length, 8 c.d.m. Breadth, 2 c.d.m. 



Marine Scotland (Greg. ), England (Donkin, Kitton), Ireland (O'Meara). A species not very 

 well known. 



N. opima Grun. (Novara, p. 100, pi. ia, f. 13 ; Ad. Schm. Atl., 

 pi. 46, f. 25-26*), plate 25, fig. 714. 



Valve elliptic or elliptic sublanceolate, with apices broadly lanceolate, 

 terminal nodules considerably distant from the apices. Striae all radiant, 

 distant, about 6 in 1 c.d.m., rather distant from the raphe and leaving a 

 hyaline space, rounded, conspicuous, round the central nodule. Length, 5-5 

 to 9-5 c.d.m. 



Marine. North Sea ; Baltic. 



N. digito-radiata Greg. (Q.j.M.S. 1856, p. 9, pi. 1, f. 32 ; 

 H.V.H. Atl., pi. 7, f. 4* ; in Types 103, 260 and 261), plate 3, fig. 130. 



Valve narrowly lanceolate, with apices obtuse-rounded ; striae very 

 delicately punctate, shortened round the central nodule, longer striae alter- 

 nating with shorter, the median ones radiate, 8 in 1 c.d.m., the terminal 

 almost straight, somewhat more compact. 



Brackish water. Antwerp, Blankenberghe. England, and probably throughout all the coasts 

 of the North Sea. 



