Central capsule lenticular, strongly flattened, about four times as broad as high, with a thin, simple-edged membrane. Nucleus lenticular, one-fourth as broad as the capsule, with numerous (twenty or more) small nucleoli. Protoplasm filled with dark pigment-granules; on the inside of the membrane in the circular periphery of the lens thirty-two dark oil-globules. Calymma lenticular, three times as broad as the capsule.
Dimensions.—Major axis of the capsule 0.2, minor 0.05; breadth of the nucleus 0.05, height 0.015; breadth of the calymma 0.6.
Habitat.—Tropical Atlantic, Station 347, surface.
Subgenus 4. Actilarcus, Haeckel.
Definition.—Central capsule lentelliptical, with three different axes.
10. Actissa larcoides, n. sp.
Central capsule lentelliptical; with three different axes, bearing the proportion 4 : 3 : 2. Nucleus spherical; its diameter equal to the shortest radius of the capsule. No nucleoli visible. Protoplasm transparent, with small vacuoles; on the inside of the thin capsule-membrane numerous (fifty to sixty) small oil-globules, regularly disposed. Calymma lentelliptical, twice as large as the central capsule.
Dimensions.—Major axis or length of the capsule 0.2, middle axis or breadth 0.15, minor axis or height 0.1; diameter of the nucleus 0.05, of the calymma 0.3-0.4.
Habitat.—Central Pacific, Station 266, surface.