108 THE DIATOMACELE OF PHILADELPHIA AND VICINITY 



BREVISTRIAT^E 



PINNULARIA ACROSPK/ERIA (BREB.) CL. 



Valve linear, gibbous in the middle and at the ends; axial area about half the width of 

 the valve; median line with approximate central pores; median area punctate; striae nearly 

 parallel, radiate at the ends, 9 in 10 M- L- 32-180 n (Cl.). 

 Blue clay. Recent, fresh water. 

 PI. 30, Fig. 7. 



PINNULARIA ACROSPILERIA VAR. TURGIDULA GRUN. ? 



Valve strongly gibbous in the middle; ends rounded; striae, 12-13 in 10 M- L- 54 p. 

 Blue clay, Gloucester, N. J., artesian well. 

 PI. 30, Fig. 8. 



PINNULARIA BLANDITA N. SP. 



Valve linear, gibbous in the middle, and with rounded ends; striae radiate in the 

 middle, convergent at the ends, 13 in 10 n; axial area about one-fourth the width of the 

 valve, widened in the middle; median line with small semicircular terminal fissures. L. 65 M- 



Pavonia, N. J., artesian well. Rare. 



PI. 30, Fig. 25. 



PINNULARIA PARVA (EHR.) CL. VAR. ? 



Valve linear, tapering to the subcapitate ends; axial area broad, lanceolate; median 

 line with approximate central pores and semicircular terminal fissures ; striae slightly diver- 

 gent in the middle and convergent at the ends, 12 in 10 p. L. 58 p. 



Differs from the type in having finer striae. 



Atco, N. J. 



PI. 30, Fig. 14. 



PINNULARIA NODOSA FORMA CAPITATA CL. 



Valve triundulate, with capitate ends; axial area about one-fourth the width of valve; 

 striae parallel, convergent at the ends, 10 in 10 n, sometimes interrupted in the middle. 

 L. 47 M- 



Fresh water. Common. 



PI. 30, Figs. 15 and 19. 



PINNULARIA POLYONCA (BREB.) LEWIS 



Valve with triundulate margins, more inflated in the middle, with capitate ends ; axial 

 area very broad; striae marginal, short, 9 in 10 n, divergent in the middle, convergent at 

 the ends. L. 97 M- 



Kirkwood Pond, N. J. 



PI. 30, Fig. 21. 



The description of Kuetzing (Species Algarum, p. 85), where he states that the margins 

 are "triundulate, the median inflation larger, apices rounded-capitate," appears to suffi- 

 ciently distinguish this species, which I believe to be the same as Brun's Navicula peripunc- 

 tata, except that the form figured (Especes Nouvelles, PI. 16, Fig. 11) is interrupted in the 

 middle, a common variation in these forms. Cleve makes Navicula polyonca Breb. equal 

 Pinnularia mesolepta, but at the same time he considers Lewis' form and also Brun's as 

 equivalent to Navicula formica Ehr., and calls it Pinnularia nodosa var. formica Ehr. P. 

 mesolepta has a narrower area than nodosa. I adhere to Lewis' identification, as in any 

 case it is the form here figured and is nearly, if not quite, the same as Brun's species. 



