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.
Habitat.—Fossil in Barbados.
5. Lithomelissa pycnoptera, n. sp.
Shell rough, papillate, with slight collar stricture. Relative length of the two joints = 1 : 3, breadth = 1 : 3. Cephalis small, hemispherical, with very small pores and a slender, straight, conical horn of twice the length. Thorax subconical, with regular circular, hexagonally framed pores, as broad as the bars. From its lower half arise three divergent, very strong feet, pyramidal, as long as the thorax, and three times as long as broad.
Dimensions.—Cephalis 0.03 diameter, thorax 0.1 diameter.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
6. Lithomelissa microstoma, n. sp.
Shell papillate, with slight collar stricture. Relative length of the two joints = 1 : 5, breadth = 1 : 5. Cephalis small, hemispherical, with a conical horn of twice the length. Thorax subspherical, with subregular circular pores, three times as broad as the bars. From its middle part arise three divergent, stout, conical feet, of half the length, and twice as long as broad. Mouth small, strongly constricted, one-fourth to one-third as broad as the thorax.
Dimensions.—Cephalis 0.03 long, 0.04 broad; thorax 0.15 diameter.
Habitat.—Fossil in Barbados.
7. Lithomelissa amphora, Stöhr.
Shell smooth, with sharp collar stricture. Relative length of the two joints = 1 : 5, breadth = 2 : 4. Cephalis small, hemispherical, with a cervical horn of the same length. Thorax ovate, with small regular circular pores, twice as broad as the bars. From its upper half arise three divergent, slender, conical feet, only one-fourth as long. Mouth constricted, with a hyaline peristome, half as broad as the thorax.
Dimensions.—Cephalis 0.013 long, 0.026 broad; thorax 0.063 long, 0.053 broad.
Habitat.—Fossil in tertiary rocks of Sicily; Grotte (Stöhr).
Subgenus 2. Micromelissa, Haeckel, 1881, Prodromus, p. 433 (sensu emendato).
Definition.—Cephalis with two divergent horns, a superior occipital horn and an inferior frontal horn.
