1 65 NAVICULA. 



Valve linear-elliptic, sometimes feebly inflated at the median portion, apices 

 broadly rounded, sometimes somewhat inflated. Raphe surrounded by a 

 broad hyaline zone, dilated round the central nodule ; costae robust, absent in 

 the centre of the valve, where their absence forms a broad false stauros, gently 

 radiate near the central nodule, convergent at the apices of the valve, about 

 5 in i c.d.m. Length, 15 to 20 c.d.m. 



Fresh water. Botanical Gardens at Brussels (Delogne). England, Ireland, France, 

 Holland, Germany, Norway, Sweden, etc. 



N. Trevelyana Donk. (Q.j.m.s. 1861, n.s. i, p. 8, pi. i, f. 2 ; 



H.V.H. Atl. Supp., f. 5 and 6*; Type No. 72), plate 2, fig. 73. 



Valve linear, gently inflated at the median portion and at the apices all are 

 broadly rounded. Raphe curved with a brace, surrounded by a narrow 

 hyaline zone, broadly dilated round the central nodule ; costae well marked, 

 n in 1 c.d.m., very radiate at the central portion, very convergent at the 

 apex of the valve. Girdle face broad, very constricted at the median portion, 

 with truncate apices. Striae interrupted between the nodule and the apex of 

 the valve by a smooth space, parallel to the connecting membrane ; smooth 

 spaces very conspicuous in girdle view, slightly visible at the edges of the 

 valve in valve view. Length, 10 to 13 c.d.m. 



Marine. Blankenberghe : washing of sand from shore. England, France, Denmark, 

 Norway, etc. 



N. rectangulata Greg. (d. of Clyde, p. 7, pi. i, f. 7; H.V.H. 



Atl. Supp , f. 7* ; Type No. 74) ; plate 2, fig. 74. 



Valve linear, with apices broadly rounded, inflated at the median portion 

 and at the apices. Raphe bordered by a narrow hyaline zone, somewhat 

 dilated round the central nodule. Striae distant, 8 or 9 in 1 c.d.m., very 

 radiate at the median portion, very convergent towards the apex of the valve. 

 Girdle face oblong, constricted at the median portion, with truncate apices. 

 Length, about 6 to 7 c.d.m. 



Marine Blankenberghe, in the sand of the shore. England, Scotland, France, Denmark. 



Var. Stauntonei Grun. (Alloioneis Staunionei Gru?i., in CI. and 

 Moll. Diat. No. 304). 



Marine. England (Firth of Tay, Rattray). 



N. cruciformis Donk. (q.j.m.s. 1861, n. s. i, p. 10, pi. i, f. 7 ; 



H.V.H. Atl. Supp., f. 8* j in Type No. 74) plate 2, fig. 75. 



Valve linear, with apices rounded, not inflated, median portion sometimes 

 very slightly inflated. Raphe not bordered by a hyaline zone / central nodule 



