Definition.—Zygospyrida with two pairs of lateral feet, without apical horn.
The genus Therospyris has two pairs of lateral feet corresponding to those of the preceding three genera, but differs from them in the complete absence of horns on the coryphal face of the shell.
1. Therospyris canis, n. sp.
Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores irregular, roundish. Basal plate with four longer pores. Surface covered with roundish tubercles. Four feet equal, divergent, about as long as the shell, thickened at the distal end, club-shaped, not forked.
Dimensions.—Shell 0.07 long, 0.11 broad; feet 0.09 long.
Habitat.—Fossil in Barbados.
2. Therospyris felis, n. sp. (Pl. [89], fig. 6).
Shell nut-shaped, mammillate, with sharp sagittal stricture. Pores large, irregularly roundish or polygonal, of somewhat different size. Basal plate with four large pores. Surface covered with hemispherical pointed mammillæ. Four feet equal, divergent, half as long as the shell, at the distal end forked, with few small branches.
Dimensions.—Shell 0.1 long, 0.15 broad; feet 0.05 long.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.