Definition.—Thorax spiny or thorny; abdomen smooth.
7. Calocyclas turris, Ehrenberg.
Calocyclas turris, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. xviii. fig. 7.
Shell with two sharp strictures. Length of the three joints = 1 : 4 : 4, breadth = 1 : 5 : 4. Cephalis hemispherical, with a stout conical horn of the same length. Thorax subspherical, thorny with small, regular, circular, quincuncial pores. Abdomen cylindrical, smooth, nearly hyaline, with very scarce, irregular, widely scattered pores. Peristome with a corona of fifteen to twenty broad, lamellar, vertical, truncate feet, about as long as the abdomen.
Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.08; breadth, a 0.03, b 0.1, c 0.08.
Habitat.—Fossil in Barbados.
8. Calocyclas hyalogaster, n. sp.
Shell with two sharp strictures. Length of the three joints = 1 : 4 : 6, breadth = 1 : 4 : 3. Cephalis subspherical, with a conical horn of twice the length. Thorax subspherical, thorny, with regular, circular pores. Abdomen cylindrical, smooth, quite hyaline, without any pores. Peristome with a corona of twelve broad, lamellar, vertical, truncate feet, half as long as the abdomen.
Dimensions.—Length of the three joints, a 0.02, b 0.08, c 0.12; breadth, a 0.02, b 0.08, c 0.06.
Habitat.—South Pacific, Station 300, depth 1375 fathoms.