Habitat.—Arctic Ocean, Kamtschatka (Bailey), Greenland (Ehrenberg).
Genus 612. Cecryphalium,[[229]] Haeckel, 1881, Prodromus, p. 434.
Definition.—Theocorida (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.
2. Cecryphalium sestrodiscus, n. sp. (Pl. [58], fig. 1).
Shell very flat, subconical, nearly discoidal, with two distinct strictures. Length of the three joints = 1 : 2 : 1, breadth = 1 : 8 : 10. Cephalis kidney-shaped, very small. Thorax flat, campanulate, with curved lateral outline; its pores irregular, polygonal, increasing in size towards the girdle. Abdomen horizontally expanded, like the brim of a hat, with five to six concentric, circular rows of pores, the pores of the inner rows twice to three times as large as those of the outer rows. (The inner circle of large, oblongish, quadrangular pores, characteristic of the preceding species, is here divided into three concentric rings by two circular hoops.)