THE DIATOMACE^E OF PHILADELPHIA AND VICINITY 95 



NAVICULA CYPRINUS (WM. SM.) 



Valve lanceolate, slightly gibbous in the middle, sub-cuneate at the ends; axial area 

 narrow; central area small; striae radiate in the middle, 10 in 10 /*, with shorter, transverse 

 striae intermediate; transverse at the extreme ends. L. 82 /*. 



Navicula digito-radiata var. cyprinus (Ehr. ?) Wm. Sm. Whether the form here figured 

 is Ehrenberg's or not, it is the species known as Pinnularia cyprinus Ehr. of Wm. Smith. 



Common in Shark River, N. J. 



PL 26, Fig. 21. 



NAVICULA REINHARDTII GRUN. 



Valve elliptical or elliptical-lanceolate, with broad, rounded ends; axial area narrow, 

 widened at the ends to the width of the valve; central area widened transversely to an irreg- 

 ular, quadrate space; striae coarse, 8 in 10 ju, distinctly lineate, alternately longer and 

 shorter in the middle, radiate, nearly transverse at the ends. L. 59 M- 



Blue clay. Rare. 



PL 26, Fig. 22. 



NAVICULA LANCEOLATA VAR. ARENARIA (DONK.) CL. 



Valve lanceolate; axial area very narrow or indistinct; central area small, rounded; 

 striae radiate, 11 in 10 ju in the middle, closer at the ends. L. 47-54 p. 

 Navicula arenaria Donk. 

 Shark River, N. J. 

 PL 26, Fig. 23. 



NAVICULA SALINARUM GRUN. 



Valve elliptical-lanceolate with produced sub-capitate or rostrate ends ; striae radiate 

 in the middle, longer and shorter; transverse at the ends, lineate. L. 32 ju 

 Atlantic City, N. J. 

 PL 26, Fig. 24. 



NAVICULA VIRIDULA VAR. ROSTELLATA KUETZ. 



Valve lanceolate with rostrate ends; axial area very narrow, central area orbicular; 

 striae radiate in the middle, about 12 in 10 /z, convergent at the ends and closer. L. 43 /*. 

 Common in fresh water. 

 PL 26, Fig. 16. 



NAVICULA GRACILIS VAR. SCHIZONEMOIDES (EHR.) V. H. 



Valve lanceolate, obtuse; axial area widened in the middle; striae radiate in the middle, 

 about 12 in 10 /z, transverse or slightly convergent at the ends. L. 45-60 p.. Occurs in 

 gelatinous tubes; usually found free. 



Colletonema neglectum Thwaites. 



Fresh water. 



PL 26, Fig. 19. 



NAVICULA RAMOSISSIMA (AG.) CL. 



Valve lanceolate, sub-acute; axial area very narrow; central area scarcely widened; 

 striae, 12 in 10 n, parallel throughout. L. 45 M- 

 Micromega ramosissimum Ag. 

 Schizonema smithii Kuetz. (not Ag.). 

 East River, N. Y. 

 PL 26, Fig. 14. 

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