Habitat.—Mediterranean (Messina), surface.
4. Zygostephanus ramosus, n. sp.
Both rings elliptical, of nearly equal height, armed with numerous branched spines, which are arranged on each ring in two divergent rows; the branches of the spines are curved and partly protect the open gates. No sagittal constriction.
Dimensions.—Height of the rings 0.07, breadth 0.09.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
Subgenus 2. Zygostephaniscus, Haeckel, 1881, Prodromus, p. 446.
Definition.—The two vertical rings of different heights; the frontal ring higher than the sagittal ring, therefore with a sagittal constriction in the median plane.
5. Zygostephanus reniformis, n. sp.
Frontal ring kidney-shaped, in the upper half convex, in the lower concave, in the latter with a deep sagittal constriction, armed with numerous irregular short spines. Sagittal ring thicker and lower, only two-thirds as high, with four pairs of short divergent spines (two ventral and two dorsal pairs).
Dimensions.—Height of the frontal ring 0.13, breadth 0.2.