Dimensions.—Diameter of the cortical shell 0.15, of the medullary shell 0.05; breadth of the gates 0.05, of the bridges 0.025.
Habitat.—North Pacific, Station 253, depth 3125 fathoms.
6. Hexapyle dodecantha, n. sp. (Pl. [48], fig. 16).
Cortical shell triangular, thorny, with rounded corners, three and a half times as broad as the medullary shell. Twelve stronger radial spines, six opposite in pairs on each side of the discoidal shell, as prolongations of the lateral edges of the triangular gates, which are about the same breadth as the half girdles between them.
Dimensions.—Diameter of the cortical shell 0.21, of the medullary shell 0.06; breadth of the gates and of the bridges 0.06.
Habitat.—Pacific, central area, Station 270, surface.
7. Hexapyle polyacantha, n. sp.
Cortical shell circular, thorny, with a circle of numerous conical radial spines in the periphery; its diameter nearly three times as great as that of the medullary shell. Three half-girdles half as broad as the three kidney-shaped gates on each side of the discoidal shell.
Dimensions.—Diameter of the cortical shell 0.11, of the medullary shell 0.04; breadth of the gates 0.04, of the bridges between them 0.02.
Habitat.—Pacific, central area, Station 271, depth 2425 fathoms.