Page:Scientific results HMS Challenger vol 18 part 2.djvu/525

Rh dilated into a very wide mouth. Pores small, of nearly equal size and similar form, of the same breadth as the bars.

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.09; breadth, a 0.03, b 0.06, c 0.12.

Habitat.—Cosmopolitan; Atlantic, Pacific; many stations, at different depths.

Definition.—Pores of the thorax and of the abdomen of different sizes or dissimilar forms.

6. Theoconus jovis, n. sp. (Pl. 69, fig. 4).

Shell bell-shaped, nearly conical. Length of the three joints = 5 : 6 : 7, breadth = 4 : 10 : 14. Cephalis nearly cylindrical, large, little curved, with a very large, oblique, pyramidal horn, as long as the two first joints together. Thorax and the broader abdomen irregularly bell-shaped, dilated towards the wide mouth. Pores circular, somewhat irregularly disposed, gradually increasing in size towards the mouth.

Dimensions.—Length of the three joints, a 0.05, b 0.06, c 0.07; breadth, a 0.04, b 0.1, c 0.14.

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

7. Theoconus junonis, n. sp. (Pl. 69, fig. 7).

Shell nearly conical. Length of the three joints = 4 : 5 : 8, breadth = 3 : 8 : 11. Cephalis ovate, with a large apical opening at the base of the vertical compressed horn, which has about the same length. Thorax and the broader abdomen together conical, gradually dilated towards the wide mouth. Thorax with a bosom-like protuberance on one side. Pores circular, gradually increasing in size.

Dimensions.—Length of the three joints, a 0.04, b 0.05, c 0.08; breadth, a 0.03, b 0.08, c 0.11.

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

8. Theoconus longicornis, n. sp.

Shell conical, thorny. Length of the three joints = 1 : 2 : 4, breadth = 1 : 3 : 6. Cephalis nearly spherical, with a very large, cylindrical, perpendicular, straight horn, once and a half to twice as long as the whole shell. Thorax conical. Abdomen nearly hemispherical, with wide open mouth. Pores circular, four to six times as broad in the thick-walled spiny abdomen as in the thin-walled rough thorax.

Dimensions.—Length of the three joints, a 0.03, b 0.06, c 0.12; breadth, a 0.03, b 0.09, c 0.18.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms; also fossil in Barbados.