Page:Scientific results HMS Challenger vol 18 part 2.djvu/222

1098 1. Tricolospyris kantiana, n. sp. (Pl. 88, fig. 10).

Shell smooth, one and a half times as long as broad, with two deep transverse strictures. Pores of the cephalis large, roundish, of nearly equal size. Cupola and thorax hemispherical, of about the same size and form, with numerous and small, double-contoured, roundish pores.

Dimensions.—Shell 0.12 long, 0.08 broad; ring 0.04 long.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

2. Tricolospyris leibnitziana, n. sp. (Pl. 88, fig. 9).

Shell spiny, twice as long as broad, with two deep transverse strictures. Pores of the cephalis large, roundish, polygonally framed, of very different size; two middle transverse rows of smaller pores enclosed between a superior and an inferior row of very large pores. Cupola and thorax hemispherical, about equal, with much smaller and very numerous roundish pores.

Dimensions.—Shell 0.15 long, 0.07 broad; ring 0.06 long.

Habitat.—Western Tropical Pacific, Station 224, depth 1850 fathoms.

3. Tricolospyris baconiana, n. sp. (Pl. 88, fig. 8).

Shell rough, twice as long as broad, with two sharp strictures. Pores of the cephalis large, very irregular, partly lobated. Cupola hemispherical, smaller than the campanulate thorax, both with smaller irregular pores.

Dimensions.—Shell 0.15 long, 0.08 broad; ring 0.06 long.

Habitat.—Western Tropical Pacific, Station 215, depth 2500 fathoms.

4. Tricolospyris newtoniana, n. sp. (Pl. 88, fig. 11).

Shell spiny, slender, three times as long as broad, with two distinct strictures. Pores of the cephalis very large, irregular. Cupola hemispherical, only one-third as long as the slender inversely conical abdomen, both with irregular, much smaller pores.

Dimensions.—Shell 0.22 long, 0.08 broad; ring 0.05 long.

Habitat.—Western Tropical Pacific, Station 206, depth 2100 fathoms.

Definition.— without free basal feet, with three distinct joints, separated by two transverse strictures; lattice-work of the shell double or spongy.

The genus Perispyris differs from the preceding Tricolospyris, its ancestral form, in the development of a secondary outer shell, which encloses the inner primary one either like an enveloping cortical shell or like a spongy veil. This is produced by the concrescence of meeting branches, which arise from spines of the inner shell.