2. Pterocanium gravidum, n. sp., (Pl. [73], fig. 3).
Shell campanulate, nearly three-sided pyramidal, smooth. Length of the three joints = 1 : 4 : 3, breadth = 1 : 6 : 10. Cephalis subspherical, with a pyramidal straight horn of twice the length. Thorax hemispherical, without prominent swellings. Abdomen shorter, with three concave basal bays; its network prolonged to the ends of the feet. Pores in the thorax and abdomen of nearly equal size, irregular, roundish. Feet from the girdle strongly divergent, with convex back.
Dimensions.—Length of the three joints, a 0.015, b 0.075, c 0.06; breadth, a 0.02, b 0.12, c 0.2.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
3. Pterocanium orcinum, n. sp. (Pl. [73], fig. 2).
Shell campanulate, nearly three-sided pyramidal, covered with conical spines. Length of the three joints = 1 : 4 : 3, breadth = 1 : 5 : 6. Cephalis hemispherical, with a conical horn of the same length. Thorax without prominent swellings, with subregular, circular pores. Abdomen shorter, with three concave basal edges and irregular, polygonal pores. Feet from the girdle strongly divergent, nearly straight.
Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.06; breadth, a 0.03, b 0.1, c 0.12.
Habitat.—Central Pacific, Station 263 to 274, depth 2350 to 2925 fathoms.
4. Pterocanium contiguum, Ehrenberg.
Pterocanium contiguum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. xvii. fig. 7.