1. Larcospira lentelliptica, n. sp.
Cortical shell with smooth surface, four times as long as the lentelliptical medullary shell. Perimeter of the lateral plane elliptical, one and a half times as long as broad, without constrictions. One lateral wing of the transverse girdle is more strongly developed and turns around the other in two to three simple spiral turns.
Dimensions.—Length of the cortical shell 0.2, breadth 0.16; length of the medullary shell 0.05, breadth 0.04.
Habitat.—Pacific, central area, Station 265, depth 2900 fathoms.
2. Larcospira quadrangula, n. sp. (Pl. [49], fig. 3).
Cortical shell with thorny surface, three times as long as the lentelliptical medullary shell. Perimeter of the lateral plane nearly quadrangular, with four rounded corners (on the poles of two crossed diagonal axes), one and a third times as long as broad, with one sagittal constriction at the poles of the principal axis. One lateral wing of the transverse girdle turns around the other in one and a half to two simple spiral turns.
Dimensions.—Length of the cortical shell 0.18, breadth 0.14; length of the medullary shell 0.06, breadth 0.04.
Habitat.—Pacific, central area, Station 274, depth 2750 fathoms.
3. Larcospira sexangula, n. sp.
Cortical shell with spiny surface, four times as long as the hexagonal medullary shell. Perimeter of the lateral plane nearly hexagonal, one and a half times as long as broad, with six rounded corners (two on the poles of the principal axis, four on the poles of two crossed diagonal axes), with three slight ring-like constrictions. One lateral wing of the transverse girdle turns around the other in two to two and a half simple spiral turns.