NAV1CULA. 185 



var. Cyprinus. (AT. Cyprinus IV. Sm., H.V.H. Atl., pi. 7, f. 3* j 

 Type No. 78), plate 3, fig 131. 



Differs from the type form by the inflation in the median portion. 

 Length, 6 to 8 c.d.m. Breadth in the median portion, 1*5 to 275 c.d.m. 



Marine. Ostend (Deby) ; Blankenberghe (H.Y H.) ; England (frequent). 



N. Reinhardtii Grun. ! {Stauroneis Reinhardtii Grun., Nov., 

 p. 566, pi. 4, f. 19 ; H.V.H. Atl., pi. 1, f. 5 and 6* ; Type No. 79), plate 3, 

 fig. 132. 



Valve short, elliptic or lanceolate, with apices very obtuse-rounded, median 

 portion abruptly inflated. Raphe surrounded by a narrow hyaline zone, 

 dilated in form of stauros round the central nodule. Stria? surrounding the 

 nodule alternately long and short, the median radiate, the terminal almost 

 straight, all very strongly punctate, and about 9 in 1 c.d.m., except those in 

 the neighbourhood of the nodule which are more distant. Length, 3-5 to 6 

 c.d.m. Breadth, about 1*5 c.d.m. 



Fresh water. Rather common : Antwerp, Louvain, Brussels probably England and other 

 places. 



The preceding and the following forms are generally mixed together. 



var. gracilior Grun. (in H.V.H. Types du Syn. No. 71, A 7 ! digtto- 

 radiata var. striolata Grun. in Arc. D. ; Type No. 80.) 



Very similar to N. digito-radiata, from which it cannot be distinguished 

 under a low magnification, but from which it is differentiated by its 

 habitat and by the strongly punctate character of its stria?. 



Fresh water. Rouge-Goitre (Delogne). 



77/. Strice radiate up to the apices of the valves. 



N. distans (W. Sm.) H.V.H. {Pinnularia dislans IV. Sm., 

 S.B.D., pi. 1, f. 56, pi. 18, f. 169 ; H.V.H. Atl. Supp., f. 18*), plate 3, fig. 133. 



Valve lanceolate, with sub-acute apices. Raphe placed in a sulcus, 

 inflected on each side of the central nodule and forming round the raphe a 

 broad hyaline zone. Central nodule surrounded (outside the sulcus) by a 

 rounded hyaline zone. Stria? very robust and distant, about 4 in 1 c.d.m., 

 radiate up to the apices of the valve. Length, 9 to 13 c.d.m. 



Marine. Blankenberghe (very rare). England, and probably on all the coasts of the North 

 Sea. 



N. longa Greg. (T.M.S., 1856, iv., p. 47, pi. 5, f. 18, sub. Pinnu- 

 laria) ; Ad. Schm. Atl., pi. 47, fig. 6*), plate 25, fig. 716. 



Valve very narrowly lanceolate-subrhomboidal with subacute apices. 

 Raphe surrounded by a very narrow hyaline zone. Stria? robust, radiate up to 



