Fresh and brackish water. Not common. Pl. 40, Fig. 2. ANOMOEONEIS SERIANS (BRÉB.) CL. Valve lanceolate, acute; axial area lanceolate; striæ, 24 in 10 µ; puncta elongate. Not common in this locality, but abundant northwards; fossil in the peat deposits of New England. May's Landing, N. J. Pl. 17, Fig. 12. Forma minor--Valve rhombic-lanceolate, smaller than the type. May's Landing, N. J. Pl. 17, Fig. 13. ANOMOEONEIS FOLLIS (EHR.) CL. Valve rhomboid, tumid in the middle and obtuse at the produced ends. Central area lanceolate; striæ radiate in the middle, transverse at the ends. _Navicula follis_ Ehr. _Navicula trochus_ Kuetz. {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 striæ 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; striæ transverse in the middle, slightly divergent at the ends, 16 in 10 µ; terminal fissures slightly curved in the same direction; longitudinal line median. L. 82 µ. 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; striæ parallel or nearly so, 16 to 18 in 10 µ. _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; striæ radiate in the middle, elsewhere parallel, about 20 in 10 µ, finely punctate; longitudinal line marginal, scarcely visible; the striæ become fainter toward the axial area. Occasional in streams and in the blue clay. Abundant in a water-trough at Ashbourne, Pa. Pl. 21, Fig. 8.