Page:Scientific results HMS Challenger vol 18 part 1.djvu/336

128 one pore; the major spine somewhat longer than the diameter of the shell, the minor scarcely one-third or one-half as long.

Dimensions.—Diameter of the sphere 0.14, pores 0.006, bars 0.002; length of the major spine 0.16 to 0.18, of the minor 0.05 to 0.07, basal breadth 0.02.

Habitat.—Indian Ocean, Zanzibar, 2200 fathoms, Pullen.

4. Xiphostylus gallus, n. sp.

Pores regular, circular, five times as broad as the bars. Twelve to sixteen pores on the half equator. Surface smooth. Polar spines very unequal; the major conical spine one and a half to three times as long as the diameter of the sphere; the minor pommel-shaped, scarcely one-third as long (length of both spines very variable).

Dimensions.—Diameter of the sphere 0.13, pores 0.01, bars 0.002; length of the major spine 0.2 to 0.4, of the minor 0.05 to 0.08.

Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.

5. Xiphostylus alauda, n. sp. (Pl. 14, fig. 15).

Lithomespilus alauda, Haeckel, 1881, Prodrom. et Atlas, ''loc. cit.''

Pores subregular, circular, three to four times as broad as the bars; fifteen to eighteen on the half equator. Surface a little rough. Polar spines irregularly conical or pyramidal, scarcely as long as the radius of the sphere; one spine simple, the other composed of a bunch of four or five spines united at the base.

Dimensions.—Diameter of the sphere 0.11, pores 0.01, bars 0.003; length of the polar spines 0.03 to 0.05, basal breadth 0.02.

Habitat.—Pacific, central area, Station 272, depth 2600 fathoms.

6. Xiphostylus anhinga, Haeckel.

Rhabdolithis pipa, Bury, 1862, Polycystins of Barbados, pl. iii. fig. 4.

Pores subregular, circular, about the same breadth as the bars; eight to ten on the half equator. Surface smooth or a little rough. Polar spines cylindrical, very irregularly curved like S or contorted, the major three to six times as long as the diameter of the sphere, the minor scarcely one-fourth as long as the former, at the end truncated.

Dimensions.—Diameter of the sphere 0.07, pores and bars 0.005; length of the major polar spine 0.2 to 0.4, of the minor 0.06 to 0.09, basal breadth 0.01.

Habitat.—Fossil in the Barbados rocks.

Definition.—Pores of the spherical shell regular, of nearly equal size and form; surface thorny or spiny (other than the two large polar spines).