Habitat.—Equatorial Atlantic, Station 347, surface.
2. Histiastrum excisum, n. sp.
Arms four times as long as broad at their base, and twice as broad at their rounded blunt distal end as at their base; their lateral edges rectilinear, divergent. Central disk with three to four rings, somewhat broader than their distal end. Patagium incomplete, connecting only the basal half of the arms, with three to four concave chamber-rows, on the margin concave. (May be regarded as Euchitonia mülleri, with four arms.)
Dimensions.—Radius of each arm 0.2, basal breadth 0.05, distal breadth 0.1.
Habitat.—Atlantic, surface, Canary Islands.
3. Histiastrum velatum, n. sp. (Pl. [46], fig. 4).
Dictyastrum velatum, Haeckel, 1879, Atlas (pl. xlvi. fig. 4).
Arms pear-shaped, rapidly increasing from their narrow base, nearly circular, little longer than broad; each with eight to nine transverse chamber-rows; their lateral edges at their base concave, at their end circular. Central disk with three to four rings, somewhat smaller than one arm. Patagium complete, with six to seven radial beams, filling out perfectly the intervals between the arms. A peculiar girdle of finer network and equal breadth surrounds the whole equatorial periphery of the disk, and gives it the appearance of a square with rounded corners.
Dimensions.—Radius of each arm 0.2, basal breadth 0.03, distal breadth 0.12.
Habitat.—South Atlantic, Station 330, surface.