Valve linear-elliptic; axial area a stauros widened outward and unilateral. Striæ of the median layer of radiating rows of oblong alveoli. Along the coast. Not common. Pl. 17, Fig. 15. The type form and its numerous varieties are quite ubiquitous. Very large specimens occur in the Antarctic regions, especially in material from Ross Island, S. Victoria Land (Shackleton Ant. Exp.). BRÉBISSONIA GRUN. (1860) (named after Alphonse de Brébisson, the distinguished French naturalist) Frustules stipitate; valve lanceolate; striæ transverse in the middle, radiate at the ends. Median area narrow, central nodule elongated, terminal fissures at a distance from the ends. Valve with an outer finely punctate stratum. At one end of one valve in each frustule is found a conspicuous punctum, the plasma pore of Otto Mueller, through which the frustule is connected with the gelatinous stipe, analogous to the pore in Diatoma connecting the zig-zag frustules. Chromatophore single, lying on one girdle and passing over to each valve. BRÉBISSONIA BOECKII (KUETZ.) GRUN. Valve lanceolate, with sub-acute apices; striæ, 3-4 in 10 µ, not reaching the median line. Blue clay. Very rare. Common in brackish water at Chestertown, Md. (T. C. Palmer) Pl. 17, Fig. 7. {80}BRÉBISSONIA PALMERII, N. SP. Valve rhombic-lanceolate, with cuneate ends and produced apices. Central nodule more elongate and terminal fissures further from the ends than in B. boeckii. Pavonia, N. J. (artesian well, depth of 40 ft.). Rare. Pl. 17, Fig. 8. I take pleasure in naming this species after Mr. T. Chalkley Palmer, of Media, Pa., the author of numerous papers on the Diatomaceæ. Lewis partly describes a similar form, which he does not name, as a species of Navicula found in the blue clay at Kaighn's Point, N. J. (Lewis, "New and Intermediate Forms," etc., p. 15, Pl. 1, Fig. 8.) ANOMOEONEIS PFITZER (1871) (anomoios, unlike, and neis (naus), a boat) Valve lanceolate, axial area narrow, central area widened; transverse striæ punctate, the puncta in longitudinal rows or interrupted by blank lines. A single chromatophore lies along one of the girdle sides and extends over the valves, each of the two parts being deeply notched or slit at the ends. According to Schmitz there are two pyrenoids, but Heinzerling thinks there is but one. Cleve considers this genus not well founded, as it is based upon the cell contents of but one species, the structure of the other species not being known. As the forms here described are easily recognized by the interrupted puncta, the genus is, at least, convenient. ANOMOEONEIS SPHÆROPHORA (KUETZ.) CL. Valve elliptic-lanceolate, ends rostrate-capitate. Axial area narrow, central area rounded, larger on one side of the median line than the other. Striæ very slightly radiate, 16 in 10 µ, punctate, the puncta interrupted by longitudinal blank lines. Pfitzer states that the central plasma mass is unequal on the two sides. _Navicula sphærophora_ Kuetz.