Habitat.—Mediterranean, Messina (R. Hertwig), surface.
5. Plagiacantha verticillata, n. sp.
Spines curved, three-sided prismatic, with six to nine verticils of three divergent branches, decreasing in size towards the distal end; the branches of the first verticil about twice as long as those of the fourth verticil. All branches simple, slightly curved, bristle-shaped.
Dimensions.—Length of the spines 0.27, of the basal branches 0.12.
Habitat.—South Pacific, Station 296, surface.
6. Plagiacantha elatine, n. sp.
Spines straight, three-sided prismatic, with prominent wing-like edges and ten to twelve verticils of three divergent branches, decreasing in size towards the distal end; the branches of the three or four basal verticils are again ramified and much larger than the simple branches of the distal verticils.
Dimensions.—Length of the spines 0.36, of the basal branches 0.14.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.