Page:Scientific results HMS Challenger vol 18 part 2.djvu/199

Rh 7. Dictyospyris gigas, Bütschli.

Dictyospyris gigas, Bütschli, 1880, Zeitschr. f. wiss. Zool., vol. xxxvi., p. 539, Taf. xxxii. fig. 14a, 14b.

Shell subspherical, smooth, with a half (ventral) sagittal stricture, and a nearly complete internal ring. Pores very numerous and small, circular. No larger annular pores. Basal plate with three large collar pores (the sternal odd pore apparently divided into two jugular pores by the visible free procolumella.) (Compare Circospyris gigas, p. 1072 = Dictyospyris gigas, Ehrenberg).

Dimensions.—Shell 0.1 long, 0.14 broad.

Habitat.—Fossil in Barbados.

Definition.—Basal plate with four large collar pores (two larger posterior cardinal and two smaller anterior jugular pores).

8. Dictyospyris fenestra, Ehrenberg.

Dictyospyris fenestra, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. xix. fig. 11.

Shell nearly cubical, smooth, without external sagittal stricture. Internal sagittal ring complete. Pores small, roundish; on each side of the ring two crossed pairs of large, square, equal, annular pores. Basal plate also with four longer pores of nearly equal size.

Dimensions.—Shell 0.05 long, 0.07 broad.

Habitat.—Fossil in Barbados.

9. Dictyospyris tetrastoma, Ehrenberg.

Dictyospyris tetrastoma, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 70, Taf. xix. fig. 12.

Shell nut-shaped, tuberculate, with slight sagittal stricture. Pores numerous, irregular, roundish. No larger annular pores. Basal plate with four large ovate collar pores (the two cardinal twice as large as the two jugular pores).

Dimensions.—Shell 0.05 long, 0.07 broad.

Habitat.—Cosmopolitan; Atlantic, Indian, Pacific; also fossil in Barbados and Sicily.

10. Dictyospyris spinulosa, Ehrenberg.

Dictyospyris spinulosa, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 70, Taf. xix. fig. 13.

? Ceratospyris borealis, Bailey, 1856, Amer. Journ. of Science and Arts, vol. xxii. pl. i. fig. 3.

Shell nut-shaped, spinulate, without external stricture, with an internal free sagittal ring. Pores numerous, irregular, roundish; on each side of the ring two pairs of very large square pores. Basal plate with four large collar pores.