two pairs of knobs; two other pairs in the apical rod. Basilar rod horizontal, straight. Basal ring with six pairs of similar knobs, three on each side. Basal gates ovate or nearly triangular.
Dimensions.—Height of the sagittal ring 0.09, breadth 0.07.
Habitat.—Central Pacific, Stations 265 to 268, depth 2700 to 2900 fathoms.
2. Semantis distoma, n. sp.
Sagittal and basal ring nearly of the same form as in the preceding species, but half as thick and armed with numerous branched spines which are about half as long as the diameter of the main gate, and with thin and curved pointed branches.
Dimensions.—Height of the sagittal ring 0.11, breadth 0.08.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
3. Semantis dipyla, n. sp.
Sagittal ring kidney-shaped, very thick, with six pairs of short, thorny, or irregularly tuberculated knobs (two dorsal, two apical, and two ventral pairs). Basal ring smooth, scarcely half as thick, horizontal, with two semicircular basal gates, about half as broad as the main gate. From the two opposite lateral corners of the basal ring two slender upwardly curved spines arise, resembling the basal part of a commencing frontal ring.
Dimensions.—Height of the sagittal ring 0.08, breadth 0.05.
Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.
4. Semantis sigillum, n. sp. (Pl. 92, fig. 1).
Sagittal ring elliptical, with four pairs of stout arborescent spines (two apical and two equatorial pairs), which are irregularly branched and forked, with numerous thin lateral branches. Apex with a short conical trifid vertical horn. Basal ring thorny, with obliquely descending slightly curved bars.
Dimensions.—Height of the sagittal ring 0.12, breadth 0.09.
Habitat.—South Pacific, Station 300, depth 1375 fathoms.
5. Semantis distephanus, n. sp. (Pl. 83, fig. 3).
Sagittal ring thin, semicircular, smaller than the thin basal ring, which exhibits two semicircular gates. Both rings are armed with numerous small spines of equal size, which on the former are arranged in two, on the latter in three regular rows. (The basal rod of the sagittal ring, separating the two basal gates, in fig. 3 is, by mistake, not distinctly enough drawn.)
Dimensions.—Height of the sagittal ring 0.06, breadth 0.08.
Habitat.—Tropical Atlantic, Station 348, surface.
