irregularly branched or arborescent in the distal half, with ten to thirty blunt, thickened or papillate, terminal branches.
Dimensions.—Length of three joints, a 0.02, b 0.04, c 0.08; breadth, a 0.04, b 0.06, c 0.08.
Habitat.—Central Pacific, Station 268, depth, 2900 fathoms.
3. Thyrsocyrtis furcata, n. sp.
Shell ovate, thorny, with two slight strictures. Length of the three joints = 1 : 1 : 3, breadth = 1 : 2 : 3. Cephalis hemispherical, with a pyramidal smooth horn of twice the length. Pores of the thorax and abdomen nearly equal, regular, circular, quincuncial. Feet very broad, forked, about as long as the abdomen, much divergent; the outer fork-branch as long as the simple basal half of the foot, and twice as long as the inner or axial branch.
Dimensions.—Length of the three joints, a 0.03, b 0.03, c 0.09; breadth, a 0.04, b 0.06, c 0.09.
Habitat.—Tropical Atlantic, Station 338, depth 1990 fathoms.
4. Thyrsocyrtis rhizopus, Haeckel.
Shell pear-shaped, smooth, with two slight strictures. Length of the three joints = 1 : 2 : 4, breadth = 1 : 3 : 5. Cephalis ovate, with a stout, sword-shaped horn of the same length. Pores regular, circular, twice as broad in the inflated abdomen as in the truncate, conical thorax. Feet cylindrical, parallel, vertical, straight, divided at the distal end into two short fork-branches.
Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.08; breadth, a 0.02, b 0.06, c 0.1.
Habitat.—Fossil in Barbados.
5. Thyrsocyrtis rhizopodium, n. sp. (Pl. 68, fig. 8).
Shell campanulate-conical, with deep collar, but without lumbar stricture. Length of the three joints = 3 : 4 : 10, breadth = 4 : 10 : 15. Cephalis subspherical, with a small conical horn of the same length. Pores regular, circular, quincuncial, three to four times as large in the inflated abdomen as in the truncate, conical thorax. Feet cylindrical, slightly divergent, about as long as the abdomen, S-shaped, bent outwards, irregularly branched in the distal half, with tuberculate terminal branches.
Dimensions.—Length of the three joints, a 0.03, b 0.04, c 0.1; breadth, a 0.04, b 0.1, c 0.15.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
6. Thyrsocyrtis radicata, Haeckel.
Shell campanulate-conical, with two distinct strictures, length of the three joints = 1 : 2 : 4, breadth = 1 : 4 : 6. Cephalis subspherical, with a small conical horn of half the length. Pores regular,
