Page:Scientific results HMS Challenger vol 18 part 2.djvu/375

Rh 4. Sethamphora mongolfieri, Haeckel.



Shell urceolate, smooth, with distinct collar stricture. Length of the two joints = 2 : 9, breadth = 3 : 7. Cephalis campanulate, with eighteen ribs and small pores. Thorax nearly ellipsoidal, with eighteen prominent ribs, and eighteen longitudinal rows of regular circular pores between them (eight pores in each row; therefore 144 pores altogether). Mouth constricted, only one-third as broad as the thorax.

Dimensions.—Cephalis 0.02 long, 0.03 broad; thorax 0.09 long, 0.07 broad.

Habitat.—Fossil in Barbados.

5. Sethamphora costata, n. sp. Pl. 62, fig. 3.

Shell urceolate, smooth, very similar to the preceding species; also with eighteen longitudinal ribs, but differing in the larger size of the cephalis and its pores, and in the more slender and ovate form of the thorax. Length of the two joints = 5 : 10, breadth = 5 : 8. Pores of the cephalis more numerous. Mouth half as broad as the thorax.

Dimensions.—Cephalis 0.05 long, 0.05 broad; thorax 0.1 long, 0.08 broad.

Habitat.—Central Pacific, Stations 265 to 274, depth 2350 to 2925 fathoms.

6. Sethamphora serrata, n. sp.

Shell ovate, spinulate, without external collar stricture. Length of the two joints = 1 : 6, breadth = 2 : 4. Cephalis flat, cap-shaped, with small circular pores. Thorax ovate, truncate, with eighteen serrate longitudinal ribs, alternating with eighteen longitudinal rows of short and broad rather oblong pores (twenty to thirty pores in each row). Mouth strongly constricted, only one-fourth as broad as the thorax.

Dimensions.—Cephalis 0.02 long, 0.04 broad; thorax 0.12 long, 0.08 broad.

Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.

7. Sethamphora ampulla, Haeckel.



Shell broad, urceolate, spiny, with sharp collar stricture. Length of the two joints = 1 : 4, breadth = 1 : 5. Cephalis subspherical, with few small pores (in figs. 12a and 12b of Ehrenberg, loc. cit., broken off, so that the four pores of the cortinar septum appear). Thorax inflated, bottle-shaped, with twenty prominent, sharply dentate ribs, alternating with twenty longitudinal rows of circular pores (about eight pores in each row). Mouth flat, constricted, one-third as broad as the thorax.

Dimensions.—Cephalis 0.025 long, 0.03 broad; thorax 0.1 long, 0.14 broad.

Habitat.—Fossil in Barbados.