THE DIATOMACE.E OF PHILADELPHIA AND VICINITY 81 



Reported by Lewis as very rare in the blue clay of the Delaware River. I have not 

 seen it in this locality. The figure is drawn from a specimen in the W. Bridgewater, Mass., 

 deposit. 



PL 17, Fig. 14. 



CALONEIS CLEVE (1894) 



(calos, beautiful) 



Valve convex, linear or lanceolate in general outline, with transverse, smooth or finely 

 punctate striae crossed by one or more longitudinal lines. 



Endochrome of two chromatophores lying one on each valve, entire in some species 

 and deeply cleft in others. 



CALONEIS LIBER (WM. SM.) CL. 



Valve linear, with parallel margins and rounded ends; axial area narrow, central area 

 orbicular; striae transverse in the middle, slightly divergent at the ends, 16 in 10 ju; terminal 

 fissures slightly curved in the same direction; longitudinal line median. L. 82 p. 



Atlantic coast, chiefly southward. 



PL 40, Fig. 1. 



CALONEIS SILICULA (EHR.) CL. 



Valve linear, gibbous in the middle, with broad sub-cuneate ends; axial area narrow, 

 central area rounded; longitudinal line marginal; striae parallel or nearly so, 16 to 18 in 10 /x. 

 Navicula silicula Ehr. 

 Navicula limosa Donk. 

 Blue clay. 

 PL 21, Fig. 3 (var. genuina CL). 



CALONEIS SILICULA VAR. INFLATA (GRUN.) CL. 



Valve gibbous in the middle, with rounded ends; central area elliptical. 

 Schuylkill River. 

 PL 21, Fig. 4. 



C. silicula may be recognized by its yellow color when dry. Its varieties are extremely 

 numerous. 



CALONEIS TRINODIS (LEWIS) 



Valve divided into three segments of equal width; ends cuneate and usually produced; 

 axial area elliptical with a lunate marking on each side; striae radiate in the middle, else- 

 where parallel, about 20 in 10 n, finely punctate; longitudinal line marginal, scarcely 

 visible; the striae become fainter toward the axial area. 



Occasional in streams and in the blue clay. Abundant in a water-trough at Ash- 

 bourne, Pa. 



PL 21, Fig. 8. 



I have retained Lewis' name as specific. Lewis, wrongly, I think, ascribes his species 

 to Navicula trinodis Wm. Sm., which is not figured by Smith, but is illustrated by Van 

 Heurck (Syn. PL 14, Fig. 31a), and is named by Cleve Navicula contenta var. biceps Arnott. 



