Page:Scientific results HMS Challenger vol 18 part 2.djvu/550

1426 13. Theocampe costata, n. sp. (Pl. 66, fig. 24).

Shell almost ovate, with two sharp strictures. Length of the three joints = 2 : 4 : 8, breadth = 3 : 5 : 7. Cephalis hemispherical. Thorax twice as large, also hemispherical, both with regular, circular, quincuncial pores. Abdomen broader, with numerous longitudinal ribs, alternating with longitudinal rows of larger pores. Mouth constricted, half as broad as the thorax.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.08; breadth, a 0.03, b 0.05, c 0.07.

Habitat.—Indian Ocean, Sunda Straits (Rabbe), surface.

14. Theocampe cryptocephala, Haeckel.

Eucyrtidium cryptocephalum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 70, Taf. xi. fig. 11.

Shell ovate, rough, with two distinct strictures. Length of the three joints = 1 : 2 : 4, breadth = 1 : 4 : 5. Cephalis subspherical, its lower half hidden in the campanulate thorax. Abdomen subspherical, twice as broad as the constricted mouth. Pores subregular, circular, quincuncial, twice as broad in the abdomen as in the thorax.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.07; breadth, a 0.025, b 0.07, c 0.09.

Habitat.—Fossil in Barbados.

Definition.— with the basal mouth of the shell fenestrated (vel Tricyrtida eradiata clausa).

Definition.— (vel Tricyrtida eradiata clausa), with an apical horn, and a terminal lattice-plate on the mouth.

The genus Theocapsa, and the two following genera, represent together the small subfamily of Theocapsida, or of those Tricyrtida in which the mouth is closed by a lattice-plate, and external radial appendages are wanting. Theocapsa may be derived from Theocorys by fenestration of the constricted mouth.

Definition.—Thorax of about the same size as the abdomen, or somewhat larger; pores of both nearly equal in size and similar in form.