1 88 NAVICULA. 



We give the description and particulars as to the dispersion of N. 

 capitata according to the authors. We reproduce (fig. 719^) the figure which 

 Ehrenberg gives of his form in the ' : Mikrogeologie " and (fig. 7 19^) that of 

 Schumann, which authors refer to it, although it is absolutely different. 



We have not in any of our collections a form referred by any serious 

 diatomist to N. capitata Ehr. We therefore only insert the N. capitata 

 Ehr. to record our opinion that it ought to be erased from our Catalogues, 

 since it is impossible to know what form Ehrenberg had in view. 



N. dicephala W. Sm. ! (S.B.D. L, p. 53, pi. 17, f. 157 ; H.V.H. 



Atl., pi. 8, f. 33 and 34*, H.V.H. in Types No. 43, 343, 382, 481) 5 plate 3, 

 fig. 138. 



Valve narrow, linear, with apices rostrate-capitate ; striae much shortened 

 round the central nodule, radiate up to the apices of the valve, and about 9 

 to n in 1 c.d.m. Length 2*5 to 4 c.d.m. Breadth, 1 to 1*25 c.d.m. 



Only differs from N. Anglica Ralfs previously described by the linear form 

 of the valve. 



Fresh water. Ard. Lig. (De Wild. ). England, Scotland, Ireland. 



N. apiculata Breb. ! (Diat. Cherb., f. 5*, non W. Sm.); plate 25, 

 fig. 720. 



Valve narrowly linear-lanceolate with rostrate apices. Stria; radiate, very 

 robust 9 or 10 in i c.d.m., reaching to the raphe and almost touching the 

 central nodule, around which they are more radiate and more distant. Girdle 

 face narrow, constricted at the median portion and showing the striae radiate. 

 It is this which distinguishes the N. apiculata from N. cancellata, of which, 

 in other respects, it has all the appearance. Length, 5 to 7 c.d.m. Breadth, 

 1 c.d.m. 



Marine. England, France. Found probably on other shores washed by the North Sea. 



N. Kiitzingiana H.L. Sm. ! (Spec. Typ., No. 287, A.J.Q.M., 



1878. N. arenicola Grun. ! 1882 ; Foss. Diat, pi. 30, f. 76-77*) ; plate 25, 

 fig. 721. 



Valve linear-elliptic, narrow, very gently inflated at the median portion ; 

 striae radiate, about 20 in 1 c.d.m., but the median much more distant. 

 Length of valve, 1*5 to 2 c.d.m. Breadth, 0.5 c.d.m. 



Marine. France, England. 



