Page:Scientific results HMS Challenger vol 18 part 2.djvu/609

Rh 5. Lithomitra eruca, n. sp. (Pl. 79, fig. 3).

Shell subcylindrical, diminishing slightly towards both ends, with ten to fifteen slight strictures. On each joint a single transverse row of circular pores, descending obliquely in the wall. The two or three first joints form together a roundish cephalis. Usually each joint is three times as broad as long.

Dimensions.—Length of the shell (with twelve joints) 0.2; length of each joint (on an average) 0.016, breadth 0.05.

Habitat.—Central Pacific, Station 265 to 268, depth 2700 to 2900 fathoms; fossil in Barbados.

6. Lithomitra chrysalis, n. sp. (Pl. 79, fig. 4).

Shell subcylindrical, diminishing slightly towards both ends, with elegant longitudinal ribs, and with five to eight slight strictures. Each of the upper joints with two (or sometimes three) transverse rows of small pores; each of the lower joints with only a single row.

Dimensions.—Length of the shell (with six joints) 0.11; length of each joint 0.01 to 0.015, breadth 0.04 to 0.05.

Habitat.—Central Pacific, Station 266, depth 2750 fathoms.

Definition.—All (or the majority) of the joints of the shell with several transverse rows of pores, in variable number.

7. Lithomitra cylindrica, n. sp.

Shell cylindrical, smooth, with twelve to sixteen internal septal rings (without external strictures). On each joint two transverse rows of small, regular, circular pores. The hemispherical cephalis also has two rows of pores. Each joint is twice as broad as long.

Dimensions.—Length of the shell (with sixteen joints) 0.3; length of each joint 0.02, breadth 0.04.

Habitat.—South Pacific, Station 297, depth 1775 fathoms.

8. Lithomitra costata, Haeckel.

Dictyomitra costata, Stöhr, 1880, Palæontogr., vol. xxvi. p. 101, Taf. iii. fig. 23.

Shell with longitudinal ribs, in the upper half conical, in the lower half cylindrical, with six to eight slight strictures. Small, circular pores in regular transverse rows; three rows in each upper joint, two rows in each lower joint (the last joints sometimes confluent).