THE DIATOMACE^E OF PHILADELPHIA AND VICINITY 33 



BIDDXJLPHIA L^EVIS EHR. 



Valve suborbicular or triangular, with short, truncate processes. Surface with fine 

 puncta about 13 in 10 n radiating in straight or curved lines toward the circumference and 

 with fine spurs at intervals. Nearer one process than the other, and about half way between 

 centre and circumference, are two small spines, one on each side. Quite variable hi size. 



Blue clay. Common along the coast. 



PL 7, Fig. 9. 



Fig. 10 (magnification about 260 diameters only) illustrates sporangial frustules dis- 

 covered by Mr. T. Chalkley Palmer at Reedy Island, Delaware River. In frustules having 

 a cylindrical form, the endochrome lines the cell-walls in the form of granules which 

 become congregated toward the centre in the sporangia. 



BIDDULPHIA ALTERNANS (BAIL.) V. H. 



Valve triangular or, rarely, quadrangular, with sides straight or slightly concave, 

 usually unequal. Angles obtuse, separated from the centre by costate lines. Surface with 

 puncta of irregular shape, large at the centre, with smaller puncta interspersed. In many 

 valves several lines appearing like costae extend inward from the border in various direc- 

 tions. Angles with small puncta in transverse and longitudinal rows. 



Triceratium alternans Bail. 



Blue clay. Along the coast. 



PI. 6, Fig. 7 and probably Fig. 8. 



BIDDULPHIA RETICULUM (EHR.) 



Frustule quadrangular. Valve triangular with straight or concave sides and rounded 

 angles. Surface convex at the centre and angles. Markings of unequal size, mostly larger 

 at the centre, scattered; at the angles, small puncta in longitudinal rows. 



Triceratium sculptum Shad. 



Triceratium punctatum Br. 



Triceratium obtusum Br. 



For explanation of the synonymy see "Biddulphoid Forms of N. A. Diat.," Proc. 

 Acad. Nat. Sci., 1900, p. 724. 



Blue clay. Along the coast. 



PI. 6, Fig. 5. 



(c) ANAULE^E 

 EUNOTOGRAMMA WEISSE (1854) 



(eu, well, noton, a back, and gramma) 



Frustule quadrangular. Valve elliptical or lunate divided by septa which constrict 

 the margin. Surface flat with punctate markings. 



EUNOTOGRAMMA UEVE GRUN. 



Valve lunate with obtuse ends. Septa, from four to eleven or more. Surface with 

 puncta in transverse and longitudinal rows, sometimes indistinct and scattered. 

 Shark River. Rare. More common southward. Fossil at Buckshutem, N. J. 

 PI. 7, Fig. 11, and PI. 10, Fig. 15. 

 I am unable to distinguish between E. laeve and E. debile, as intermediate forms occur. 





