Definition.—Zygospyrida with six basal feet, without apical horn.
The genus Cantharospyris differs from the preceding two hexapodal genera in the absence of horns on the coryphal face, and has therefore the same relation to them that the hornless Tristylospyris bears to the one-horned Tripospyris and the three-horned Triceraspyris.
1. Cantharospyris carabus, n. sp.
Shell nut-shaped, with deep sagittal stricture and irregular roundish pores. Basal plate with six larger pores. Six feet of different sizes, cylindrical, curved; three primary feet (one caudal and two pectoral) about as long as the shell and twice as long as the three secondary feet.
Dimensions.—Shell 0.08 long, 0.12 broad; feet 0.05 to 0.09 long.
Habitat.—Tropical Atlantic, Station 338, depth 1990 fathoms; Central Pacific, Station 268, depth 2900 fathoms.
2. Cantharospyris ateuchus, Haeckel.
Ceratospyris ateuchus, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. xxi. fig. 4.
Shell nut-shaped, tuberculate, with slight sagittal stricture and unequal circular pores. Basal plate with six larger pores. The two pectoral feet very large and stout, four to six times as long as the shell, widely divergent, curved. The four other feet much smaller and thinner, about as long as the shell.
Dimensions.—Shell 0.06 long, 0.08 broad; length of the two larger feet 0.2 to 0.3, of the four smaller 0.05 to 0.07.