4. Lithoptera tetragona, n. sp.
Four equatorial spines compressed, four-edged, with large latticed apophyses, each crossed by four transverse beams, which are connected at regular distances by eight to twelve rods parallel to the spine. (Therefore each wing with three rows of square meshes.) Wings placed in the equatorial plane and grown together by their meeting lateral ends, forming a square equatorial girdle of lattice-work. Sixteen smaller spines simple, thin, prismatic, without apophyses.
Dimensions.—Diameter of the square body 0.4; length of the inner square 0.22.
Habitat.—North Pacific, Station 244, surface.
Subgenus 2. Lithopterella, Haeckel.
Definition.—Twelve spines (four equatorial and eight tropical) with transverse apophyses; the eight polar spines simple, without apophyses.
5. Lithoptera quadrata, n. sp. (Pl. 131, fig. 10).
Twelve spines with transverse apophyses; eight (polar) spines simple, small, without apophyses. Four equatorial spines very large and stout, compressed, each crossed by four transverse beams, which are connected by eight to ten rods parallel to the spine (therefore each wing with three rows of irregular rectangular meshes). Wings placed in the equatorial plane and grown together by their meeting lateral ends, forming a square equatorial girdle of lattice-work. Eight tropical spines thin, crossed by a long and thin transverse beam, which bears on its distal side eight to ten rods parallel to the spine.
Dimensions.—Diagonal of the square body 0.35; length of the inner square 0.18.
Habitat.—South Atlantic, Station 326, surface.
6. Lithoptera dodecaptera, n. sp.
Twelve spines with transverse apophyses; eight (polar) spines simple, small, without apophyses. Four equatorial spines very large, quadrangular; each crossed by three transverse beams, which are connected by ten to twelve rods parallel to the spine (therefore each wing with two rows of square meshes). Wings placed as in Lithoptera mülleri. Eight tropical spines much thinner, crossed each by two transverse beams, which are connected by six to eight rods parallel to the spine (therefore each wing with one row of rectangular meshes).
Dimensions.—Diagonal of the square body 0.4; length of the inner square 0.25.
Habitat.—Central Pacific, Station 271, surface.
Subgenus 3. Lithopteromma, Haeckel.
Definition.—All twenty spines with transverse apophyses.
