Habitat.—Fossil in Barbados.
6. Clathrocyclas domina, Haeckel.
Podocyrtis domina sinensis, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 82, Taf. xiv. fig. 4.
Shell subconical, with two slight strictures. Length of the three joints = 1 : 2 : 4, breadth = 1 : 3 : 4. Cephalis ovate, with a conical horn of the same length (and sometimes with some little accessory thorns at its base). Pores subregular, circular, quincuncial, in the dilated abdomen (with six to eight transverse rows), twice to four times as large as in the hemispherical thorax (with four to six rows). Coronal of the wide peristome with nine to twelve short, triangular, divergent feet, half as long as the cephalis (in Ehrenberg's figure incomplete).
Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.08; breadth, a 0.02, b 0.06, c 0.08.
Habitat.—Central Pacific, Stations 263 to 268, depth 2650 to 3000 fathoms; also fossil in Barbados.
Subgenus 2. Clathrocycloma, Haeckel.
Definition.—Shell flatly conical, often widely campanulate, or nearly discoidal. Cephalis commonly with two or more horns.
7. Clathrocyclas alcmenæ, n. sp. (Pl. [59], fig. 6).
Shell conical, with two indistinct strictures. Length of the three joints = 2 : 10 : 1, breadth = 2 : 12 : 14. Cephalis hemispherical, with two divergent, pyramidal horns; frontal horn as long as the cephalis, occipital horn of twice the length. Thorax conical, with large hexagonal meshes, increasing gradually in size towards the short abdomen, which is represented only by a single circular girdle of small, square, abdominal pores. Coronal of the peristome with twenty to thirty triangular, divergent, nearly horizontal feet, as long as the cephalis.