NAVICULA. 167 



surrounded by a broad, cuneate pseudo-stauros ; striae flexuous 12 to 13 in 

 t c.d.m., very radiate near the central nodule ; very convergent at the apex of 

 the valve. Girdle view constricted at the median portion, with truncate apices. 

 Length 5 to 12 c.d.m. 



Marine. Blankenberghe, in the sand of the shore. England, Norway. 



N. quadratarea Ad. Schm. (Nordsee, p. 90, pi. 2, f. 26*; 



JV. pinnularia C/., Sv. o. Norsk. Diat., p. 224, pi. 1, f. 1-2), plate 25, 



fig. 74- 



Valve linear-oblong, with rounded apices; stria; parallel, 9 or 10 in 

 1 c.d.m,, reaching to the raphe, and leaving round the central nodule a 

 broad quadrangular stauroform hyaline space. Length, about 9 c.d.m. ; 

 breadth, 1*25 c.d.m. 



Marine. North Sea (coasts of Ireland and Scandinavia). 



