Page:Scientific results HMS Challenger vol 18 part 2.djvu/590

1466 3. Stichophæna gœtheana, n. sp.

Shell ovate, one and a half times as long as broad, rough, with five internal annular septa. The six joints gradually increase in length and breadth. The last joint is the broadest, and half as long as the five others together. The hemispherical cephalis bears a pyramidal horn of twice the length. From the thorax arise nine radial ribs, which attain their greatest height in the fourth joint and reach the fifth joint, but are not developed in the last ovate joint. Pores subregular, circular.

Dimensions.—Length of the shell (with six joints) 0.22, breadth 0.14. Length of the single joints, a 0.02, b 0.025, c 0.03, d 0.035, e 0.04, f 0.7.

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

Definition.—Last joint of the shell pointed, armed with a polar, basal spine, or a bunch of spines.

4. Stichophæna nonaria, n. sp. (Pl. 76, fig. 6).

Shell nearly spindle-shaped, with five or six distinct strictures. The third joint is the broadest and longest, and twice as long as the second and the fifth joints. Along the second or third middle joint (beginning from the second or third) descend nine prominent longitudinal ribs. Cephalis hemispherical, with two short, conical, divergent horns. Last joint inversely conical, armed with several strong, conical, divergent spines.

Dimensions.—Length of the shell (with seven joints) 0.23, of the third joint 0.05, of the last 0.04; breadth 0.1.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

5. Stichophæna novena, n. sp. (Pl. 76, fig. 7).

Shell nearly spindle-shaped, with eight or nine deep strictures. The third joint is the broadest, campanulate, in its lower half with nine prominent ribs, which disappear beyond the third stricture. The following joints are alternately longer and shorter, and decrease gradually in breadth. Thorax hemispherical. Cephalis small, hemispherical, with a conical horn of the same length. Last joint also hemispherical, scarcely larger than the cephalis, with a bunch of conical, divergent spines.

Dimensions.—Length of the shell (with nine joints) 0.25, of the third joint 0.05, of the last 0.02; breadth 0.1.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.