Page:Scientific results HMS Challenger vol 18 part 2.djvu/204

1080 bearing an irregularly branched horn. Caudal foot short conical, simple. Two pectoral feet half as long as the shell, angular, subvertical, irregularly branched.

Dimensions.—Shell 0.15 diameter, ring 0.1 long, pectoral feet 0.07 long.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

5. Tholospyris cupola, n. sp. (Pl. 89, fig. 4).

Shell pear-shaped or cupola-shaped, smooth, with slight sagittal stricture. Cephalis not distinctly separated from the galea, as the ring in the uppermost part of the shell-wall becomes obliterated. Pores irregularly polygonal, small and numerous. Basal plate with four large pores. Apical horn and the three divergent feet, irregularly branched; feet nearly as long as the shell, about four times as long as the horn.

Dimensions.—Shell 0.14 diameter, ring 0.1 long, feet 0.12 long.

Habitat.—Central Pacific, Station 274, depth 2750 fathoms.

Definition.— with two lateral basal feet and an apical horn.

The genus Lophospyris differs from the preceding Tholospyris, its probable ancestral form, in the absence of the caudal foot, and therefore bears to it the same relation that Dipospyris does to Tripospyris. The two pectoral feet are alone developed and are placed opposite in the frontal plane. Lophospyris may also be derived from Dipospyris by the formation of a galea.

1. Lophospyris dipodiscus, n. sp. (Pl. 95, fig. 14).

Shell ovate, spinulate, with sharp transverse coronal constriction. Cupola hemispherical, half as large as the nut-shaped cephalis. Pores irregularly roundish, much larger on the sagittal constriction. Apical horn pyramidal, about half as long as the shell. Two lateral feet cylindrical, strongly curved, about as long as the shell, with some irregular branches; together forming a nearly complete circle.

Dimensions.—Shell 0.09 long, 0.08 broad; ring 0.04 long, feet 0.08 long.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

2. Lophospyris acuminata, Haeckel.

Ceratospyris acuminata, R. Hertwig, 1879, Organism. d. Radiol., p. 70, Taf. vii. fig. 2.

Shell campanulate, smooth, without external transverse stricture. Cupola conical, half as long and broad as the nut-shaped cephalis. Pores irregularly roundish, on each side of the sagittal