THE DIATOMACE.E OF PHILADELPHIA AND VICINITY 89 



STAURONEIS SALINA WM. SM. 



Valve lanceolate, obtuse; stauros narrow, with short, scattered striae at the margin, 

 18 in 10 n, punctate. L. 65 /*. 

 Along the coast. Common. 

 PI. 27, Fig. 6. 



STATJRONEIS LEGTJMEN EHR. 



Valve elliptical-lanceolate, inflated in the middle, with produced sub-capitate or ros- 

 trate ends separated by diaphragms. Stauros wide, striated at the margins; axial area 

 very narrow; striae radiate, about 26 (?) in 10 /*, punctate. L. 28 ju. 



Pavonia, N. J., artesian well. 



PI. 39, Fig. 15. 



In Cleve's description and Van Heurck's figure, the median inflation is "not larger 

 than the others." In the present form the median inflation is wider. 



STAURONEIS ACUTA WM. SM. 



Valve rhombic-lanceolate, obtuse; a diaphragm at each end; stauros widened outwards; 

 striae, 15 or 16 in 10 ^, punctate. L. 130 /u. 

 Blue clay. 

 PI. 27, Fig. 2. 



STAURONEIS AMERICANA A. S. 



Valve elliptical-lanceolate, obtuse; striae, 14 in 10 p. L. 119 /*. 



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



The only specimen found is asymmetrical with respect to the transverse axis. 



On Plate 40, Fig. 4, is illustrated an abnormal form of Stauroneis, apparently near S. 

 acuta, having an elongated central nodule and radiating, curved and coarsely punctate 

 striae. Blue clay. 



STAURONEIS SMITHII GRUN. 



Valve lanceolate, inflated in the middle and at the ends, which have diaphragms and 

 are produced into rostrate apices; stauros reaching the margin; striae parallel, about 25 in 

 10 n (28 to 30, Cleve), distinctly punctate. 



Not uncommon in meadow pools near Newtown Square. 



PI. 27, Fig. 11. 



STAURONEIS CRUCICULA (GRUN.) CL. 



Valve lanceolate, with obtuse, produced ends; stauros bifid; striae, 24 in 10 n, oblique, 

 parallel to the branches of the stauros, closer at the ends, punctate. L. 32 p. 

 Newtown Square. East Park Reservoir. Rare. 

 PI. 27, Fig. 10. 



NAVICULA BORY (1826) 

 (dim. of navis, a boat) 



Valve linear to elliptical; ends acute, rounded, rostrate, capitate or truncate; axial 

 area usually distinct; central area distinct, rounded or rarely extended into a transverse 

 fascia; striae transverse or radiate, punctate; central area not dilated into a transverse 

 stauros nor into horns. 



