Dimensions.—Diameter of the phacoid shell 0.1, of the medullary shell 0.04; length of the arms 0.14, greatest breadth 0.08.
Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.
4. Stauractura quadrata, n. sp.
Phacoid shell twice as broad as the medullary shell, with seven pores on the radius. Arms nearly square, about as large as the phacoid shell, with a strong pyramidal terminal spine at the distal end. Patagium complete, between every two arms triangular, with rectilinear parallel rows of chambers; it connects the end points of the arm radius in such a manner that the whole shell becomes a regular square.
Dimensions.—Diameter of the phacoid shell 0.09, of the medullary shell 0.045; length of the arms 0.1, greatest breadth 0.08.
Habitat.—South Pacific, Station 295, depth 1500 fathoms.
Genus 210. Pentactura,[[249]] Haeckel, 1881, Prodromus, p. 459.
Definition.—Coccodiscida with five chambered arms on the margin of the circular or pentagonal disk, without a connecting patagium.
The genus Pentactura possesses five free radial arms, and resembles Pentalastrum among the Porodiscida. The distance of the five arms seems to be sometimes equal, at other times different in one and the same species.
1. Pentactura pentactis, Haeckel.