Dimensions.—Length of the shell 0.2, height 0.17, breadth 0.1.
Habitat.—Tropical Atlantic, Stations 341 to 349, surface, and at various depths.
7. Conchidium magasella, n. sp.
Shell laterally compressed, with two equal valves, very similar to the preceding species, but differing in the following characters:—Proportion of the three axes = 6 : 4 : 3. Margins of the valves with smaller and more numerous teeth; on each side of one valve sixteen to eighteen short conical teeth. Pores smaller and more numerous, about as broad as the bars.
Dimensions.—Length of the shell 0.24, height 0.16, breadth 0.12.
Habitat.—Indian Ocean, Madagascar (Rabbe), surface.
8. Conchidium productum, n. sp.
Shell laterally compressed, prolonged, with two equal valves, similar to the two preceding species, differing in the following characters:—Proportion of the three axes = 3 : 2 : 1. Margins of the valves smooth in the anterior and posterior quarter, dentate in the middle lateral half; on each side of one valve ten to twelve strong conical teeth. Horns of the aboral hinge prolonged, conical, half as long as the shell, the ventral somewhat larger than the dorsal. Pores regular, circular, twice as broad as the bars.
Dimensions.—Length of the shell 0.25, height 0.15, breadth 0.08.
Habitat.—North Atlantic, Station 354, surface.