Shell rough, thin-walled, with distinct collar stricture. Length of the two joints = 6 : 8, breadth = 6 : 7. Cephalis subspherical, large, with circular, double-contoured pores. Thorax cylindrical, with irregular, roundish pores, the size of which, like the thickness of the wall, decreases gradually towards the truncate mouth, which has no ring-like peristome.
Dimensions.—Cephalis 0.06 long, 0.06 broad; thorax 0.08 long, 0.07 broad.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
14. Dictyocephalus cavea, n. sp.
Shell rough, thin-walled, with slight collar stricture. Length of the two joints = 3 : 10, breadth = 5 : 7. Cephalis hemispherical, thorny, with numerous regular, circular pores. Thorax subcylindrical, with very large, circular, hexagonally-framed pores (in nine longitudinal alternating rows), three to five times as broad as the cephalic pores. Mouth truncate, wide open, without ring-like peristome.
Dimensions.—Cephalis 0.06 long, 0.1 broad; thorax 0.2 long, 0.14 broad.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
15. Dictyocephalus capito, Ehrenberg.
Dictyocephalus capito, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 289, Taf. vii. fig. 24.
Shell smooth, thin-walled, with sharp collar stricture. Length of the two joints = 7 : 9, breadth = 6 : 8. Cephalis ovate, with numerous irregular, roundish, densely-crowded pores. Thorax ovate, with very few widely-scattered, irregular, roundish pores (broken off in Ehrenberg's figure). Mouth truncate, little constricted, without ring-like peristome.