Habitat.—North Pacific, Stations 252 to 256, surface.
2. Castanella thomsoni, n. sp.
Pores regular, circular, of equal size, hexagonally framed, twice as broad as the bars. Radial bristles about as long as the diameter of one pore. Mouth with four strong, conical teeth, forming a regular cross, four times as long as a bristle.
Dimensions.—Diameter of the shell 0.7 to 0.8, of the pores 0.03.
Habitat.—South Pacific, Stations 295 to 298, surface.
3. Castanella campbelli, n. sp.
Pores regular, circular, hexagonally framed, three times as broad as the bars. Radial bristles half as long as the radius of the shell. Mouth with a coronet of eight conical, parallel teeth, of the same length as the bristles, but four to six times as thick.
Dimensions.—Diameter of the shell 0.4 to 0.45, of the pores 0.025.
Habitat.—Central Pacific, Stations 270 to 274, surface.
4. Castanella sloggetti, n. sp.