Page:Scientific results HMS Challenger vol 18 part 2.djvu/522

1398 Cephalis large, trilobed, with a short, oblique horn of half the length. Thorax campanulate, conical, separated from the abdomen by a circle of smaller pores and a deep stricture. Abdomen flat, discoidal, with three circles of larger pores.

Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.04; breadth, a 0.06, b 0.12, c 0.18.

Habitat.—Fossil in Barbados.

4. Theocalyptra cornuta, Haeckel.

Carpocanium cornutum, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 287, Taf. ii. fig. 9.

Halicalyptra cornuta, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. xxii. p. 5, pl. i. figs. 13, 14.

Lophophæna cornuta, Haeckel, 1862, Monogr. d. Radiol., p. 299.

Shell campanulate-conical, with two sharp strictures. Length of the three joints = 1 : 3 : 1, breadth = 1 : 4 : 5. Cephalis subspherical, with two stout, pyramidal, divergent horns of twice the length. Thorax campanulate, with eight to ten transverse rows of roundish or nearly square pores, increasing in size towards the abdomen, which is flatly expanded, nearly discoidal, separated by a circle of smaller pores; the last circle of pores (on the margin) is larger.

Dimensions.—Length of the three joints, a 0.025, b 0.09, c 0.03; breadth, a 0.03, b 0.12, c 0.16.

Habitat.—Arctic Ocean, Kamtschatka (Bailey), Greenland (Ehrenberg).

Definition.— (vel Tricyrtida eradiata aperta) with discoidal or flatly expanded abdomen. Cephalis without horn.

The genus Cecryphalium has the same flat, conical, or nearly discoidal shell as the preceding Theocalyptra, its ancestral genus, but differs from it in the complete absence of horns on the cephalis.

1. Cecryphalium lamprodiscus, n. sp. (Pl. 58, fig. 2).

Shell flatly conical, with two slight strictures. Length of the three joints = 1 : 3 : 2, breadth = 1 : 7 : 11. Cephalis roundish, very small. Thorax conical, with straight lateral outline; its pores irregular, polygonal, increasing in size towards the girdle. Abdomen little flatter than the thorax, forming its direct prolongation, with five to six circular, concentric rows of pores; the first row formed by sixty to eighty very large, oblongish, quadrangular pores, the second row by very small, the third again by larger pores; the outmost rows by very small and numerous pores.

Dimensions.—Length of the three joints, a 0.02, b 0.06, c 0.04; breadth, a 0.02, b 0.14, c 0.22.

Habitat.—Central Pacific, Station 272, surface.