Subgenus 2. Lamptidium, Haeckel.
Definition.—Abdomen with six radial ribs (three primary or perradial, and three alternate, secondary or interradial).
4. Cycladophora hexapleura, n. sp.
Lanterna chinensis, Bury, 1862, Polycystins of Barbados, pl. xiii. fig. 7.
Shell shaped like a lantern, with six sides and two sharp strictures. Length of the three joints = 1 : 2 : 8, breadth = 1 : 2 : 4. Cephalis hemispherical, with a conical spine of the same length. Thorax twice as large, hemispherical, with regular, circular pores. Abdomen nearly six-sided prismatic, with six descending, little curved ribs, and eighteen large holes between them; six superior holes interradial, ovate, six intermediate holes very large, perradial, ovate, six inferior holes triangular, interradial. Mouth six-lobed.
Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.16; breadth, a 0.03, b 0.06, c 0.1.
Habitat.—Fossil in Barbados.
5. Cycladophora pyramidalis, n. sp.
Podocyrtis sp., Bury, 1862, Polycystins of Barbados, pl. xii. fig. 2.
Shell slender, pyramidal, with six sides and two slight strictures. Length of the three joints = 1 : 4 : 12, breadth = 1 : 4 : 8. Cephalis subspherical, with a conical horn of twice the length. Thorax conical, with regular, circular pores. Abdomen truncate, pyramidal, with six strong, divergent, straight ribs, which are connected by five to six transverse, hexagonal rings; therefore six longitudinal rows of large, roundish, quadrangular meshes (four to five meshes in each row). Mouth hexagonal.