Dimensions.—Diameter of the disk (with eight rings) 0.23, of the phacoid shell 0.09, of the medullary shell 0.035.
Habitat—Pacific, central area, Station 267, depth 2700 fathoms.
2. Staurocyclia serrata, n. sp.
? Haliomma sp., Bury, 1862, Polycystins of Barbados, pl. xxii. fig. 2.
Phacoid shell twice as broad as the medullary shell, surrounded by three to four spongy rings, which are divided by thirty to forty radial beams into irregular chambers. Pores in the phacoid shell regular, circular, five on its radius; in the chambered spongy girdle much smaller and irregular. Margin dentated, with four crossed, very large, quadrangular spines, as long as the radius of the disk, with wing-shaped, serrated edges.
Dimensions.—Diameter of the disk (with four rings) 0.2, of the phacoid shell 0.1, of the medullary shell 0.05.
Habitat.—Fossil in the rocks of Barbados.
3. Staurocyclia phacostaurus, n. sp. (Pl. [37], figs. 2, 3).
Phacostaurus pyramidalis, Haeckel, 1879, MS. (as a separate genus).
Phacoid shell two and a quarter times as broad as the medullary shell, connected with it by twelve radial beams (four equatorial and eight divergent) and surrounded by one single ring, which is divided by forty radial beams into regular chambers. Pores regular, honeycomb-like in the phacoid shell, seven on its radius; smaller on the equatorial ring, three on its breadth. Four marginal spines pyramidal four-sided, as long and as broad at the base as the ring.