Dimensions.—Cephalis 0.02 long, 0.03 broad; thorax 0.09 long, 0.07 broad.
Habitat.—Fossil in Barbados.
5. Sethamphora costata, n. sp. Pl. [62], fig. 3.
Shell urceolate, smooth, very similar to the preceding species; also with eighteen longitudinal ribs, but differing in the larger size of the cephalis and its pores, and in the more slender and ovate form of the thorax. Length of the two joints = 5 : 10, breadth = 5 : 8. Pores of the cephalis more numerous. Mouth half as broad as the thorax.
Dimensions.—Cephalis 0.05 long, 0.05 broad; thorax 0.1 long, 0.08 broad.
Habitat.—Central Pacific, Stations 265 to 274, depth 2350 to 2925 fathoms.
6. Sethamphora serrata, n. sp.
Shell ovate, spinulate, without external collar stricture. Length of the two joints = 1 : 6, breadth = 2 : 4. Cephalis flat, cap-shaped, with small circular pores. Thorax ovate, truncate, with eighteen serrate longitudinal ribs, alternating with eighteen longitudinal rows of short and broad rather oblong pores (twenty to thirty pores in each row). Mouth strongly constricted, only one-fourth as broad as the thorax.
Dimensions.—Cephalis 0.02 long, 0.04 broad; thorax 0.12 long, 0.08 broad.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.