21 8 NAVICULA. 



N. formosa Greg. (T.M.S., 1856, p. 42; h.v.h. Atl., pi. n, 



f. 2* ; in Type No. 105 = Caloneis formosa mr. Holmiensis C/.), plate 5, 

 fig. 199. 



Valve linear, elliptic, with apices somewhat attenuate obtuse. Raphe sur- 

 rounded by a broad hyaline zone, elliptic lanceolate ; terminal nodules robust, 

 central nodule lateral. Marginal striae robust, finely divided transversely, 

 somewhat radiate, crossed by a narrow sulcus rather distant from the margins, 

 about 10 in 1 c.d.m. Length, about 14 c.d.m. Breadth, about 3 c.d.m. 



Marine and brackish water. Scheldt at Antwerp. England, Scotland, Ireland, Denmark, 

 Bahusie. 



N. Liburnica Grun. (Wien. Verh., i860, p. 547, pi. 1, f. 25; 



H.V.H. Atl., pi. 11, f. 3*; Type No. 133 = Cal formosa Cl.\ plate 5, 

 fig. 201. 



Differs from the preceding by its subacute apices, its smaller size, narrow 

 hyaline zone, and its more approximate stria? (12 in 1 c.d.m.). Length, 9 to 

 10 c.d.m. Breadth, 2 c.d.m. 



Marine. Blankenberghe (H.V.H. ). Ireland (O'M.). Yarmouth, England (Kitton). 



N. latiuscula Kiitz. (Bac, p. 93, pi. 5, f. 11 : N. patula IV. Sm.I 

 S.B.D. i., p. 49, pi. 16, f. 182 ; H.V.H. Atl., Supp. pi., pi. B., f. 29^*3 Type 

 906), plate 5, fig. 200. 



Valve broadly oblong or elliptic lanceolate with apices obtuse, rounded. 

 Stria? finely punctate, 14 in i c.d.m., not reaching to the raphe, scarcely 

 radiate ; raphe surrounded by a hyaline area inflated at the central nodule, 

 which is elongated, somewhat arcuate. Length, about 15 c.d.m. Breadth, 

 about 3 c.d.m. 



Fresh and brackish water. Antwerp, Tete de Flandre (H.V.H. ). Found throughout Europe. 



N. permagna Bailey. (Smithson. Contrib., 1850, Bail. Micros. 

 Observ. in Georgia, S. Carolina and Florida, p. 40, pi. 2, f. 28, 38 ; T.M.S., 

 1866, vi., n.s., p. 127, pi. 12, f. 18-21 ; H.V.H. Atl., pi. 11, f. i*j Type No. 

 134), plate 5, fig. 202. 



Valve broadly lanceolate, with subacute apices. Central nodule lateral, 

 terminal nodules robust. Raphe surrounded by a broad hyaline zone dilated 

 into a round area at the median portion. Stria? fine, about 12 in 1 c.d.m., 



