8. Acrocubus tetrapodius, n. sp.
Mitral and basal rings of the same size, square, with straight rods, sagittal ring also square. The four vertical columellæ are nearly parallel and straight, prolonged upwards into four short conical horns, downwards into four longer conical feet. (The shell has nearly the form of a geometrical cube, the eight corners of which are prolonged into eight vertical conical spines, four smaller ascending and four larger descending.)
Dimensions.—Diameter of the cube 0.09; length of the feet 0.06.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
9. Acrocubus amphithectus, n. sp. (Pl. [93], fig. 17).
Mitral ring smaller than the basal, both rings elliptical, with curved rods. Four columellæ thorny, also curved, divergent downwards, prolonged upwards into four thorny convergent horns, downwards into four larger branched divergent feet. The two sagittal horns and feet (anterior and posterior) are smaller than the two lateral (right and left); therefore the fundamental form of this species is distinctly amphithect (as in the Ctenophora).
Dimensions.—Breadth of the cube 0.12; total height 0.2.
Habitat.—South Pacific, Station 289, depth 2550 fathoms.
Genus 427. Toxarium,[[46]] n. gen.
Definition.—Tympanida with two bisected horizontal rings, connected by four vertical columellæ. In the frontal plane two galear bows project upwards, and two thoracal bows downwards.