Radial spines cylindrical, spinulate, more or less curved, longer than the diameter of the shell and about twice as broad as its bars. Meshes irregularly polygonal, of very variable form and unequal size, separated by smooth bars.
Dimensions.—Diameter of the shell 2.5, length of the spines 3.0 to 3.5, breadth 0.02.
Habitat.—Indian Ocean, Zanzibar (Pullen), depth 2200 fathoms.
Subgenus 2. Orodendrum, Haeckel.
Definition.—Radial spines branched or arborescent.
6. Oroscena huxleyi, n. sp. (Pl. [12], figs. 1, 1a).
Radial spines cylindrical, obliquely ascending and irregularly curved, about as long as the diameter of the shell and somewhat thicker than its thorny bars. A variable number of short, irregular, partly simple, partly forked, lateral branches arises from the spines. Meshes of the network very irregular, partly solid, partly hollow (fig. 1a*), the majority quadrangular. This species, the first observed form of Orosphærida (captured the 21st February 1873 at Station 5), was at the beginning of my observations, in 1876, and when I had no knowledge of the central capsule, erroneously regarded by me as a gigantic Sphæroid (of the Monosphærida) and therefore placed in Pl. [12]. The long branched spines, afterwards observed complete in another specimen, were broken off in the specimen first figured.
Dimensions.—Diameter of the shell 2.0 to 2.5, length of the spines 2 to 3 mm., breadth 0.03.
Habitat.—North Atlantic (west of Canary Islands), Station 5, depth 2740 fathoms.
7. Oroscena darwinii, n. sp.