Dimensions.—Length of the curved axis of the shell (with eight joints) 0.24, length of each joint 0.03; breadth of the second joint 0.04, of the sixth 0.08.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
8. Lithostrobus leptoceras, n. sp.
Shell horn-shaped, slenderly conical, with curved axis (like a quadrant of a circle), smooth, with twelve to fourteen slight strictures. All joints nearly of the same length, the tenth twice as broad as the second. In each joint only a single transverse row of small circular pores. Horn of the cephalis curved, bristle-shaped, half as long as the shell.
Dimensions.—Length of the curved axis of the shell (with twelve joints) 0.18, length of each joint 0.15; breadth of the second joint 0.02, of the tenth 0.04.
Habitat.—North Pacific, Station 253, depth 3125 fathoms.
9. Lithostrobus caloceras, n. sp. (Pl. 80, fig. 4).
Shell horn-shaped, conical, with curved axis, smooth, with six to eight deep strictures. All joints nearly of the same length, the sixth twice as broad as the third. On each joint a single circle of very large roundish pores, separated by two to four series of smaller pores. Horn of the cephalis conical, curved, of twice the length.
Dimensions.—Length of the curved axis of the shell (with six joints) 0.12, length of each joint 0.02; breadth of the third joint 0.04, of the sixth 0.08.
Habitat.—South Pacific, Station 297, depth 1775 fathoms.
10. Lithostrobus macroceras, n. sp.
Shell horn-shaped, slenderly conical, with curved, nearly semicircular axis, without external strictures, but with twelve to twenty internal septal rings. All joints nearly of the same length, the twelfth twice as broad as the third. On each joint three to four transverse rows of subregular, small, hexagonal pores. Horn of the cephalis conical, curved, of twice the length.
Dimensions.—Length of the curved axis of the shell (with sixteen joints) 0.32, length of each joint 0.02; breadth of the third joint 0.02, of the twelfth 0.04.
Habitat.—Central Pacific, Station 274, depth 2750 fathoms.
Subgenus 3. Cyrtostrobus, Haeckel.
Definition.—Shell conical (often more campanulate or irregular), with straight axis; joints of different lengths. Cephalis not lobate.
