Subgenus 1. Amphibrachella, Haeckel.
Definition.—Both arms equal, of the same form and size, blunt at the distal end, without a terminal spine.
1. Amphibrachium sponguroides, n. sp.
Both opposite arms of the same form and size, nearly cylindrical, three times as long as broad, with six to eight transverse septa or joints, at the distal end rounded, blunt, without a terminal spine.
Dimensions.—Radius of each arm 0.22, breadth 0.065.
Habitat.—Antarctic Ocean, Station 154, surface.
2. Amphibrachium lanceolatum, n. sp.
Both arms equal, lanceolate, in the middle part three times as broad as at the two ends, two and a half times as long as broad, with eight to nine transverse septa, at the distal end blunt, without a terminal spine.
Dimensions.—Radius of each arm 0.3, greatest breadth 0.09.
Habitat.—Pacific, central area, Station 267, depth 2700 fathoms.
3. Amphibrachium dilatatum, n. sp. (Pl. 44, fig. 6).
Both arms equal, trapezoidal, somewhat broader than long, on the convex distal end three times as broad as on the narrow base, with five to six transverse septa, without a terminal spine. Central disk large, somewhat irregular, with three to four rings, twice as broad as the base of the arms.
Dimensions.—Radius of each arm 0.32, basal breadth 0.15, terminal breadth 0.44.
Habitat.—South Atlantic, off Patagonia, Station 319, surface.
Subgenus 2. Amphibrachidium, Haeckel.
Definition.—Both arms equal, of the same size and form, with terminal spines.
4. Amphibrachium amphilonche, n. sp.
Both arms equal, lanceolate, in the middle part four times as broad as at the two ends, twice as long as broad; on the distal end of each arm is a long conical spine.
Dimensions.—Radius of each arm (without terminal spine) 0.2, breadth 0.08.
Habitat.—Pacific, central area, Station 271, depth 2425 fathoms.
