Cortical shell nearly rhombic, smooth, one and a half times as long as broad, with four strong, conical, radial spines, two on the poles of the principal axis (as prolongations of the sagittal septa), two others on the poles of the transverse axis. Transverse girdle narrow, with two pores on the isthmus. Sagittal septa longer than the medullary shell. Eight gates triangular.
Dimensions.—Length of the medullary shell 0.04, breadth 0.03; length of the cortical shell 0.18, breadth 0.12.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
7. Octopyle tetrastyle, n. sp.
Cortical shell lentelliptical, with rough surface and four angular radial spines in the lateral plane, opposite in pairs in two crossed diagonals. Lateral girdle nearly rectangular (each angle with one spine), one and a third times as long as broad. Sagittal septum longer than the hexagonal medullary shell. Eight gates egg-shaped.
Dimensions.—Length of the medullary shell 0.05, breadth 0.03; length of the cortical shell 0.16, breadth 0.12.
Habitat.—North Atlantic, Station 354, surface.
8. Octopyle tetraptera, n. sp.
Cortical shell quadrangular, with thorny surface and four latticed wing-like prolongations on the corners of the quadrangle, opposite in pairs in two crossed diagonals, each wing supported by a strong radial spine. Lateral girdle quadrangular, one and a half times as long as broad. On the isthmus of the transverse girdle four pores. Sagittal septum longer than the hexagonal medullary shell. Eight gates triangular.
Dimensions.—Length of the medullary shell 0.07, breadth 0.04; length of the cortical shell 0.24, breadth 0.16.