Dimensions.—Cephalis 0.08 long, 0.06 broad; thorax 0.04 long, 0.08 broad.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms; fossil in Barbados.
3. Lithomelissa macroceras, n. sp.
Shell spiny, with sharp collar stricture. Relative length of the two joints = 5 : 7, breadth = 5 : 6. Cephalis spherical, with a large pyramidal horn of twice the length. Thorax little longer, ovate, truncate. Both joints with regular circular pores, three times as broad as the bars. Three divergent pyramidal feet, twice as long as the cephalis, arise from the middle part of the thorax. Mouth constricted, half as broad as the thorax.
Dimensions.—Cephalis 0.05 long, 0.05 broad; thorax 0.07 long, 0.06 broad.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
4. Lithomelissa mitra, Bütschli.
Lithomelissa mitra, Bütschli, 1881, Zeitschr. f. wiss. Zool., p. 518, Taf. xxxiii. fig. 24.
Shell smooth, with distinct collar stricture. Relative length of the two joints = 5 : 4, breadth = 4 : 5. Cephalis ovate, with a slender, straight, vertical, pyramidal horn of the same length. Thorax ovate, truncate, of about the same size. Both joints with very small and numerous pores, as broad as the bars. Three feet arising from the middle part of the thorax, very small, rudimentary, pyramidal, about as long as broad. Mouth truncate, little constricted.
Dimensions.—Cephalis 0.05 long, 0.04 broad; thorax 0.04 long, 0.05 broad.