Subgenus 4. Theocapsura, Haeckel.
Definition.—Thorax much smaller than the abdomen, pores of the two different in size or form.
13. Theocapsa lamarckii, n. sp. (Pl. 66, fig. 16).
Shell slenderly ovate, rough, with two distinct strictures. Length of the three joints = 1 : 2 : 7, breadth = 1 : 4 : 5. Cephalis subspherical, with a conical horn of twice the length. Thorax conical, with regular, circular pores. Abdomen three times longer, with subregular, hexagonal pores of twice the size. Basal pole hemispherical, with very large, irregular, roundish pores.
Dimensions.—Length of the three joints, a 0.02, b 0.05, c 0.14; breadth, a 0.03, b 0.08, c 0.1.
Habitat.—Indian Ocean, Madagascar (Rabbe), surface.
14. Theocapsa cuvieri, n. sp. (Pl. 66, fig. 10).
Shell slenderly spindle-shaped, thorny, with two slight strictures. Length of the three joints = 1 : 3 : 6, breadth = 1 : 3 : 3. Cephalis subspherical, with a conical horn of the same length. Thorax conical, spiny, with regular, circular, double-edged pores. Abdomen thinner-walled, inversely conical, with irregular, roundish pores. Basal pole acute, with a bunch of larger spines.
Dimensions.—Length of the three joints, a 0.02, b 0.05, c 0.12; breadth, a 0.02, b 0.05, c 0.06.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
15. Theocapsa baerii, n. sp.
Shell slenderly spindle-shaped, smooth with two indistinct strictures. Length of the three joints = 1 : 2 : 8, breadth = 2 : 3 : 4. Cephalis hemispherical, with a thick conical horn of the same length. Abdomen four times as long as the thorax. Pores in the thorax small and numerous, regular, circular, in the abdomen twice as large, and irregularly roundish. Basal pole inversely conical, acute. (Differs from Theocapsa wolffii, Pl. 66, fig. 14, mainly in the shape of the pores.)
Dimensions.—Length of the three joints, a 0.015, b 0.03, c 0.12; breadth, a 0.03, b 0.04, c 0.06.
Habitat.—North Pacific, Station 241, depth 2300 fathoms.
16. Theocapsa rathkei, n. sp.
Shell slenderly conical, with two slight strictures. Length of the three joints = 1 : 2 : 10, breadth = 2 : 4 : 15. Cephalis small, with a large, conical horn of three times the length. Thorax small, thorny, with small irregular, roundish pores. Abdomen very large, as long and as broad as the thorax, with irregular polygonal or roundish, very large pores, the margin of which is finely denticulate. Basal pole truncate, rounded.
Dimensions.—Length of the three joints, a 0.02, b 0.05, c 0.2; breadth, a 0.04, b 0.08, c 0.3.
Habitat.—Fossil in Barbados.
