NAVICULA. 207 



var. Goeppertiana. (H.V.H. Atl., pi. 10, f. iS, Type No. 114), 

 plate 4, fig. 168. 



Valve regularly lanceolate. 



Laeken, near Brussels (Del.). 



var. undulata. (H.V.H. Atl, pi. 10, f 2 or., in Type No. 148), 

 plate 4, fig. 169. 



Margins feebly undulate. 



Not yet found in Belgium. 



var. quinquenodis (H.V.H. Atl., pi. 10, f. 21, in Type No. 

 146), plate 4, fig. 170. 



Valve showing three strong inflations on each side. 



Groenendael (Del.). 



var. ventricosa. (H.V.H.. pi. 4, f. i/>., Stauroneis venlricow 

 Kit/z.), plate 4, fig. 171. 



Valve with apices rostrate-capitate. 



Not yet found in Belgium. 

 a a. Hyaline space very broad, valve with striae perpendicular to the raphe. 



N. Pinnularia Cleve. (Sv. och Norsk D., 1868, p. 224, pi. 4, f. 1-2* ; 



N. quadratarea Ad. Schm.), plate 27, fig. 758. See under (I) Pinnularia;, 

 page 167. 



A A . Stanronciform appearance caused by the median stride being 



distant from one another. 



N. crucicula (W. Sm.). {Stauroneis W. Sm., S.B.D., i., p. 60, 

 pi. 19, f. 192 ; H.V.H., pi. 10, f. 15*; Type No. 112), plate 4, fig. 172. 



Valve broadly lanceolate or lanceolate-elliptic, with apices obtuse, some- 

 what constricted ; striae almost touching the raphe, slightly shortened near the 

 central nodule. Median striae straight, more robust and more distant, and 

 producing, under insufficient magnification, the appearance of a stauros ; the 

 others about 16 or 17 in 1 c.d.m., fine ; compact, delicately punctate, more and 

 more radiate as they are distant from the median. Length, about 4*5 c.d.m. 

 Breadth, 1*5 c.d.m. 



Brackish water. Antwerp (Scheldt), Blankenberghe. England, Ireland, Denmark. 



van protracta Grun. (Arct. D., p. 35, pi. 2, f. 38; H.V.H. Atl. 

 Supp., f. 27*; in Type No. 99), plate 4, fig. 173. 



Valve linear lanceolate, with apices broadly rostrate. Striae 18 to 21 

 in 1 c.d.m. Length, 2^25 to 3*5 c.d.m. 



Brackish water. Austruweel near Antwerp(H.V.H.). Ard. Liege. (DeWild.). Cheshire, 

 England, 



