Valves punctate and areolate sulcata The chromatophores consist of circular and compressed or irregular flat granules which lie along the wall of the cell. MELOSEIRA DISTANS (EHR.) KUETZ. Frustules cylindrical, slender, with two furrows, one on each side of the suture; valve in zone view with fine puncta in longitudinal rows; puncta in valve view scattered. L. 7-10 µ. _Meloseira nivalis_ Wm. Sm. _Coscinodiscus minor_ Wm. Sm. Fresh water. Fossil in New England deposits. Pl. 1, Figs. 8 and 9. NOTE.--In all species of Meloseira, as well as Gaillonella and Lysigonium, the frustules are so closely coherent that when the filaments are broken entire frustules are less frequently found than a union of two valves of contiguous frustules. {15}MELOSEIRA GRANULATA (EHR.) RALFS Frustules cylindrical, robust, 5-18 µ in diam., with large granules in longitudinal, sometimes spiral, lines, variable in size and arrangement in the same filament. Valve in valve view with scattered puncta. Variable in relative width and length, passing to M. crenulata. _Gaillonella granulata_ Ehr. _Orthosira punctata_ Wm. Sm. Fresh water. Fossil at Coldspring, L. I. Pl. 1, Fig. 10. MELOSEIRA CRENULATA (EHR.) KUETZ. Frustules cylindrical, with furrows on each side of the suture, 10-20 µ in diam.; puncta in longitudinal rows. Margins of valves denticulate at the junction of the frustules; valves with puncta scattered at the centre, radiate at the circumference. Common in fresh water; quite variable in size. _Gaillonella crenulata_ Ehr. _Orthosira orichalcea_ Wm. Sm. in part; not Conferva orichalcea. Mertens or Gaillonella aurichalcea Ehr. and Bailey. Pl. 1, Figs. 1 and 2. MELOSEIRA ROESEANA RAB. Frustules cylindrical, constricted toward each end, with coarse, longitudinal striæ; valve convex, striæ punctate, radiating, with several large granules at the centre. Connective zone with longitudinal rows of fine puncta. Diam. 12-45 µ. _Orthosira spinosa_ Grev. Fresh water. Media, Pa. (Palmer); not common. Pl. 1, Figs. 5 and 6. MELOSEIRA ROESEANA VAR. EPIDENDRON (EHR.) GRUN. Frustules denticulate at the margin; valve with coarse granules at the centre from which radiate lines of fine puncta. Wet rocks of the Wissahickon. Pl. 1, Figs. 3 and 4. MELOSEIRA UNDULATA (EHR.) KUETZ. Frustules single or in twos, usually broader than long, constricted near the margin. Valve with six to twelve internal projections forming with the outline of the constriction of the valve a polygonal figure within the circumference. Surface of the valve with radiating lines of puncta disappearing toward the centre, at which are numerous coarse puncta. _Meloseira gowenii_ A. Schmidt. Blue clay of Philadelphia, especially common at Twelfth and Market Sts. Pl. 1, Figs. 15, 16, 17. MELOSEIRA SULCATA KUETZ.