nearly cylindrical; both with regular, hexagonal pores, three times as broad as the bars. Peristome constricted, half as broad as the abdomen, with a corona of nine conical, vertical feet as long as the cephalis.
Dimensions.—Length of the three joints, a 0.03, b 0.07, c 0.1; breadth, a 0.035, b 0.1, c 0.1.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
Subgenus 2. Calocyclissa, Haeckel.
Definition.—Thorax spiny or thorny; abdomen smooth.
7. Calocyclas turris, Ehrenberg.
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.
9. Calocyclas erinaceus, Haeckel.
Cycladophora erinaceus, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. xviii. fig. 2.
Shell with two sharp strictures. Length of the three joints = 2 : 9 : 5, breadth = 3 : 9 : 5. Cephalis subspherical, rough, with a short and broad conical horn of half the length. Thorax ovate, densely covered with conical spines as long as the horn, and with regular, circular, quincuncial pores. Abdomen cylindrical, smooth, with irregular roundish pores of different sizes. Peristome with twelve to fifteen vertical, broad, lamellar, truncate feet half as long as the abdomen (in Ehrenberg's figure these are broken off).
Dimensions.—Length of the three joints, a 0.04, b 0.18, c 0.1; breadth, a 0.06, b 0.18, c 0.1.
Habitat.—Fossil in Barbados.
