96 THE DIATOMACE.E OF PHILADELPHIA AND VICINITY 



NAVICULA ANGLICA RALFS 



Valve elliptical, with sub-capitate or rostrate ends; axial area narrow, central area 

 small; striae radiate, 12-13 in 10 /*, distinctly punctate. L. 26 /*. 

 Fresh water. 

 PL 26, Fig. 26. 



NAVICULA GASTRUM EHR. 



Valve elliptical, with rostrate ends ; axial area narrow, central area transverse or irreg- 

 ular; stria? radiate, 9 in 10 n in the middle. L. 26 M- 

 The form here figured approaches N. anglica. 

 Kirkwood Pond, N. J. 

 PL 26, Fig. 25. 



NAVICULA DICEPHALA WM. SM. 



Valve linear, with rostrate or rostrate-capitate ends; axial area narrow, central area 

 rectangular, transverse; strise radiate, 12 in 10 M- L. 32 p. 

 Fresh water. 

 PL 27, Fig. 16. 



NAVICULA HUMILIS DONK. 



Valve elliptical, with broad, rostrate ends; axial area narrow; central area small; 

 strise radiate and distant in the middle, convergent at the ends, coarse, appearing costate, 

 averaging 9 in 10 ju- L. 19 M- As Donkin states, the striae are "very conspicuous." 



Navicula hungarica var. capitata (Ehr.) Cl. 



Navicula globiceps Lagerstedt, according to Cleve. 



Willistown, Pa. 



PL 27, Fig. 24. 



NAVICULA PINNATA PANT. ? 



Valve lanceolate, obtuse; axial area narrow, widened in the middle; stria? coarse, .7 in 

 10 M in the middle, radiate, 10 in 10 n at the ends and transverse, indistinctly lineate. L. 



40 M. 



Near Navicula ardua Mann (Diat. Albatross Voy., Cont. U. S. Nat. Herbarium Vol. 

 10, Part 5, p. 336, PL 53, Fig. 2) which, however, is said to have "strictly unbeaded costse." 



Pavonia, N. J., artesian well. 



PL 27, Fig. 20. 



NAVICULA PENNATA A. S. 



Valve lanceolate, acute; axial area narrow; central area quadrate, transverse; striae 

 radiate, coarse, 5 in 10 n, lineate. L. 68-95 M (Cleve). 

 Pavonia, N. J., artesian well. 

 PL 27, Fig. 22. 



NAVICULA INFLEXA GREG. 



Valve slightly elliptical-lanceolate, sub-acute, smooth at the ends; axial area narrow, 

 widened in the middle; striae radiate, 11 in 10 n, lineate. Frustule in zone view constricted 

 in the middle. L. 28-45 /* 



Common along the coast. 



PL 27, Figs. 18 and 19. 



