Frustules free or in mucous masses. Valve fusiform; forks about one-fourth the length of the valve; striæ transverse, punctate, 36-40 in 10 µ (J. J. Woodward). Occasional in the Delaware River. Pl. 17, Fig. 9. AMPHIPLEURA RUTILANS (TRENTEPOHL) CL. Frustules enclosed in gelatinous tubes. Valve linear-lanceolate, obtuse at the ends; forks about one-third the length of the valve; striæ, 28 in 10 µ. _Conferva rutilans_ Trentepohl. _Schizonema dillwynii_ Wm. Sm. Abundant at Belmar, N. J. Pl. 17, Fig. 10. Fig. 11 represents a portion of the gelatinous tube containing frustules. DICTYONEIS CLEVE (1890) (dictyon, a net) Frustules oblong. Valve lanceolate, constricted in the middle (in our species); an outer layer finely punctate and an inner layer of reticulations; the margin of the valve divided into large, quadrate cells. The genus Dictyoneis includes species at one time ascribed to Mastogloia and Navicula. The structure, however, is not like that of either, as the loculi are attached to the valve and are not separable as in Mastogloia, and the cell-wall is not like that of any Navicula. Cleve remarks that Dictyoneis is found in warm waters. Lewis found one specimen at Black Rock Harbor, L. I., and one in the Delaware River blue clay. The specimens here described I found living on the New Jersey coast. DICTYONEIS MARGINATA VAR. TYPICA CLEVE Valve panduriform, with cuneate lobes; axial area narrow, linear, scarcely, or not at all, widened in the middle; terminal fissures in contrary directions; outer stratum finely punctate, about 25 in 10 µ, in parallel striæ; inner stratum coarsely reticulated. Four and one-fourth times longer than broad; marginal cells, 5 in 10 µ, smaller or obsolescent in the middle of the valve; cells of the valve in irregular transverse rows, 10-12 in 10 µ. L. 93 µ. _Navicula marginata_ Lewis. Absecon, N. J. Pl. 20, Fig. 3. {79}DICTYONEIS MARGINATA VAR. COMMUTATA CLEVE Valve four and one-half times longer than broad; cells of the valve in irregular, transverse rows about 11 in 10 µ; marginal cells nearly equal, 6 in 10 µ. L. 125 µ. Absecon, N. J. Pl. 20, Fig. 2. DICTYONEIS MARGINATA VAR. MAXIMA N. VAR. Valve with cuneate segments; marginal cells, 4 in 10 µ; cells of the valve, 5 in 10 µ, obsolescent in the middle and smaller; transverse striæ, 25 in 10 µ. Atlantic Coast. Rare. Pl. 20, Fig. 1 (from a specimen found at Colon). TRACHYNEIS CLEVE (1894) (trachys, rough, and neis (naus), named from the chief species) Valve more or less linear or linear-lanceolate. It appears to be composed of three strata, one an interior, coarsely dotted, an exterior of fine puncta in longitudinal striæ, scarcely visible, and a median of transverse anastomosing costæ forming irregular alveoli. Chromatophores, two or four bands on the zone (Mereschkowsky). TRACHYNEIS ASPERA VAR. INTERMEDIA GRUN.