Ring ovate, smooth, or with a few short thorns. Apical horn oblique, curved, simple, smooth, about as long as the sagittal axis of the ring. Feet divergent, curved, simple, smooth, about as long as the horn; the caudal foot shorter than the two pectoral feet. Very variable in form and size.
Dimensions.—Height of the ring 0.06 to 0.09, breadth 0.04 to 0.06; length of the feet 0.05 to 0.1.
Habitat.—Cosmopolitan; Atlantic, Indian, Pacific, surface and in various depths.
2. Cortina typus, n. sp. (Pl. [97], fig. 1).
Ring kidney-shaped or nearly semicircular, with revolute vertical dorsal rod and strongly curved ventral rod; both rods with two pairs of spine-bunches. Apical horn nearly straight, thorny, longer than the ring, directed a little obliquely backwards. Feet slightly curved, of equal length, two to three times as long as the ring; each armed with few large bunches of curved spines, which are more developed in the caudal foot than in the two pectoral feet.
Dimensions.—Height of the ring 0.14, breadth 0.08; length of the feet 0.2 to 0.3.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
3. Cortina conifera, n. sp.
Ring subcircular, smooth. Apical horn and the three divergent feet of equal size and similar form, cylindrical, straight, about as long as the ring, at the distal end thickened, with a dimply cone (similar to Tripospyris conifera and Tripospyris eucolpa, Pl. [84], figs. 4, 7).
Dimensions.—Height of the ring 0.08, breadth 0.06; length of the feet 0.09.