110 THE DIATOMACE^ OF PHILADELPHIA AND VICINITY 



PINNULARIA STAUROPTERA (CHUN.) CL. 



Valve linear, with slightly triundulate margins tapering to the subcapitate ends; axial 

 area more than one-third the width of the valve, slightly widened in the middle; median 

 line with approximate central pores and semicircular terminal fissures; striae divergent in 

 the middle, convergent at the ends, 11 in 10 M- L- 82 /i. 



May's Landing, N. J. 



PL 30, Fig. 13. 



Some of the forms are more triundulate than the specimen figured. 



PINNULARIA STAUROPTERA VAR. INTERRUPTA CL. 



Valve linear, tapering to the subcapitate ends; axial area broad, widened in the middle 

 to a transverse fascia; striae divergent in the middle, convergent at the ends, 10 in 10 M; 

 median pores approximate. L. 118 ju. 



Schuylkill River. 



PL 30, Fig. 11. 



PINNULARIA TABELLARIA (EHR.) CL. 



Valve linear, gibbous in the middle and tapering to the subcapitate ends; axial area 

 about one-third the width of the valve, widened in the middle; median line with approxi- 

 mate central pores and bayonet-shaped terminal fissures; striae sometimes unilaterally 

 interrupted, divergent in the middle, strongly convergent at the ends, 9 in 10 p. L. 138 /n. 



Blue clay. Rare. 



PL 30, Fig. 9. 



The form here figured has coarser striae than in the type which is also usually more 

 capitate. 



P. legumen has triundulate margins, P. mesogongyla has an orbicular space, while P. 

 gibba has the space widened. According to Cleve, P. gibba has approximate central pores, 

 as has also P. mesogongyla. In what I have considered to be P. legumen, the central pores 

 are more approximate than in the other two species mentioned. In fact, all of the three 

 resemble each other closely, and are variously named by different authors. The form of 

 P. gibba here figured, which may be P. stauroptera, is not the typical form of Wm. Smith, 

 which has a narrow area and central space. There are, however, among the typical speci- 

 mens in H. L. Smith's Type Slide No. 275, smaller valves which show a resemblance. 



MARINE 



PINNULARIA RECTANGULATA (GREG.) CL. 



Valve linear, with abruptly rounded ends; axial area very narrow; central area large, 

 somewhat quadrate; striae, 7-8 in 10 p.. L. 78 M- 

 Navicula rectangulata Greg. 

 Shark River, N. J. 

 PL 29, Fig. 7. 



