Both arms equal, four times as long as broad, in the thickened distal part twice as broad as at the base, thorny, with twenty to thirty larger spines on the distal end, and a very large pyramidal spine in the longitudinal axis. (The form of the arms like that of the odd arm in Euchitonia carcinus, Pl. [43], fig. 10.)
Dimensions.—Radius of each arm 0.24, basal breadth 0.03, distal breadth 0.06.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
Subgenus 3. Amphibrachoma, Haeckel.
Definition.—Both arms of different size or form, without terminal spines.
7. Amphibrachium indicum, n. sp.
Both arms club-shaped, but very different in size and form; larger arm three times as long and twice as broad as the smaller arm; the larger with nine joints slowly increasing in size, the smaller with four joints, rapidly increasing; the terminal joint three times as broad as the basal. Distal end blunt, rounded, without spines.
Dimensions.—Radius of the larger arm 0.24, of the smaller 0.08; distal breadth of the former 0.06, of the latter 0.03; basal breadth 0.015.
Habitat.—Indian Ocean, Ceylon, Haeckel, surface.