THE DIATOMACE^E OF PHILADELPHIA AND VICINITY 105 



PINNULARIA jESTUARII CL. 



Valve linear, with rounded ends; axial area broad, less than one-third the width of 

 the valve; central area a transverse fascia; striae, 7 in 10 n, parallel except at the ends where 

 they are slightly convergent; median line flexuose, with short, terminal semicircular fis- 

 sures. L. 85 ju- 



Port Penn, Delaware River. Rare. 



PL 29, Fig. 6. 



GRACILLIM^E 



PINNULARIA MOLARIS (GRUN.) CL. 



Valve very convex, linear, with sub-cuneate ends; axial area narrow, expanded in the 

 middle to a transverse fascia reaching the margin; striae divergent in the middle, con- 

 vergent at the ends, 16 in 10 M- L- 60 /*. 

 Fresh water. 

 PL 29, Fig. 15. 



PINNULARIA LEPTOSOMA GRUN. 



Valve linear, rounded at the ends; axial area narrow; central area a broad transverse 

 fascia; striae slightly divergent in the middle and convergent at the ends, 17 in 10 p. in the 

 middle, closer at the ends. L. 56 n. 



Fresh water. Not common. 



PL 30, Fig. 10. 



CAPITATE 



PINNULARIA MESOLEPTA EHR. 



Valve linear, with triundulate margins and capitate ends; axial area narrow, widened 

 in the middle; striae divergent in the middle, convergent at the ends, about 12 in 10 n. L. 

 34 ft. 



Common in fresh water. 

 PL 29, Fig. 13. 



PINNULARIA MESOLEPTA VAR. STAURONEIFORMIS GRUN. 



Valve triundulate, capitate; axial area narrow, widened in the middle to a transverse 

 fascia, broader at the margin; striae strongly divergent hi the middle and convergent at 

 the ends, 9-10 in 10 ft. L. 70 ft. 



Pavonia, N. J., artesian well. Fresh water. 



PL 30, Fig. 20. 



PINNULARIA SUBCAPITATA GREG. 



Valve linear or linear-elliptical, with sub-capitate ends; axial area distinct, widened to 

 a transverse fascia in the middle; striae divergent in the middle, convergent at the ends, 

 13 in 10 p. L. 32 A*. 



Fresh water. 



PL 29, Fig. 20. 



