4. Theocorys ovata, n. sp. (Pl. 69, fig. 16).
Shell quite ovate, thick-walled, smooth, without external strictures. Length of the three joints = 2 : 2 : 9. breadth = 3 : 5 : 7. Cephalis conical, with a thick conical horn of the same length. Thorax and abdomen gradually dilated towards the base, and then hemispherical, constricted. Mouth scarcely one-third as broad as the abdomen, prolonged into a short tube. Pores regular, circular, disposed in transverse rows, two to three in the cephalis, two to three in the thorax, eight to ten in the abdomen.
Dimensions.—Length of the three joints, a 0.02, b 0.02, c 0.09; breadth, a 0.03, b 0.05, c 0.07.
Habitat.—Central Pacific, Stations 263 to 268, depth 2650 to 3000 fathoms.
5. Theocorys plutonis, n. sp. (Pl. 69, fig. 1).
Shell ovate, thick-walled, smooth, with two slight strictures. Length of the three joints = 2 : 5 : 4, breadth = 4 : 7 : 6. Cephalis hemispherical, with a conical, oblique horn of the same length. Thorax and abdomen only slightly inflated, gradually decreasing towards the wide, little constricted mouth. Pores subregular, circular, much larger in the abdomen and the lower half of the thorax than in the upper half and the cephalis.
Dimensions.—Length of the three joints, a 0.02, b 0.05, c 0.04; breadth, a 0.04, b 0.07, c 0.06.
Habitat.—South Pacific, Station 295, depth 1500 fathoms.
6. Theocorys scolopax, Haeckel.
Shell slender, inversely ovate, smooth. Length of the three joints = 1 : 3 : 3, breadth = 1 : 4 : 4. Cephalis subspherical, with a long, slightly curved horn, half as long as the whole shell. Thorax campanulate. Abdomen inversely ovate, twice as broad as the constricted mouth (incomplete in Ehrenberg's figure).
Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.06; breadth, a 0.02, b 0.08, c 0.08.
Habitat.—Fossil in Barbados.
Subgenus 2. Theocorythium, Haeckel.
Definition.—Pores of the thorax and of the abdomen of different sizes or dissimilar forms.
7. Theocorys dianæ, n. sp. (Pl. 69, fig. 11).
Shell almost ovate, with two deep strictures. Length of the three joints = 3 : 6 : 8, breadth = 3 : 9 : 8. Cephalis subspherical, with a slender, pyramidal horn of three times the length. Thorax
