228 NAVICULA. 



N. Falaisensis Grun. ! (H.v.H. Atl., pi. 14, f. 5* ; in Type Nos. 

 127 and 348), plate 5, fig. 232. 



Valve narrowly lanceolate, apices subrostrate ; striae rather robust, about 

 20 in 1 c.d.m., not quite reaching to the raphe, and leaving around the central 

 nodule a small rounded hyaline area. Length, about 2*5 c.d.m. 



Fresh water, Bouillon (Del.). 



N. minuscula Grun. (in H.v.H. Syn., pi. 14, f. 3*), plate 27, 

 fig. 777. 



Valve lanceolate, with subrostrate apices ; striae reaching to the raphe, 

 scarcely radiant, about 36 in 1 c.d.m., the median ones somewhat distant, and 

 consequently more distinct. Length, about 1*25 to 175 c.d.m. Breadth, 

 about o - 5 c.d.m. 



Fresh water. Ditch at Kiel, near Antwerp (H.V.H.). 



N. Bahusiensis Grun. (in H.V.H. Syn., pi. 14, f. 2*), plate 27, 

 fig. 778. 



Differs from the preceding by its larger size (1*5 to 2 - o c.d.m. in length), 

 its more vigorous striation (24 to 30 striae in 1 c.d.m.), and its habitat (salt 

 water). 

 Sweden. (Lysekl, Grun.). 



N. cocconeiformis Greg. (Q.J.M.S., 1856, iv., p. 6, pi. :, f. 22 ; 



H.V.H. Atl., pi. 14, f. 1* ; Type No. 140), plate 27, fig. 779. 



Valve small, lanceolate, inflated at the median portion with obtuse apices. 

 Raphe bordered by a narrow hyaline area, somewhat dilated round the central 

 nodule. Striae very finely radiate, convergent, 28 to 30 in 1 c.d.m. at the 

 apices of the valve, 18 in 1 c.d.m. round the central nodule; the latter 

 alternately long and short. Length, about 3^5 c.d.m. Breadth, 1-25 c.d.m- 

 at the median inflation. 



Fresh water. Scotland, Ireland, etc. 



N. Bulnheimii Grun. ! (H.v.H. Atl., pi. 14, f. 6a*), plate 5, fig. 

 233- 



Valve very narrowly lanceolate, with subacute apices ; striae feeble, parallel, 

 about 30 in i c.d.m. The two median striae more vigorous than the others. 

 Length about 2 c.d.m. 



Marine ? Not yet found in Belgium. 



var. Belgica Grun. ! (in Type No. 113). 



Valves somewhat more obtuse, with girdle face broader and con- 

 necting zone finely striated lengthwise. 

 Marine. Ostend. 



