The genus Axellipsis differs from the simple Cenellipsis in a very peculiar character, namely, the presence of an inner siliceous bar marking the minor axis of the ellipsoidal shell. If in some forms of Druppula (e.g., Pl. [39], fig. 3) we remove the central medullary shell and prolong both beams (connecting it with the cortical shell) till they unite in the centre, we shall arrive at Axellipsis. Therefore Axellipsis may be derived in the same way from Druppula as Axoprunum is from Lithatractus, by phyletic loss of the medullary shell.
1. Axellipsis perforata, n. sp.
Proportion of the major axis of the ellipsoid to the minor = 3 : 2. Pores of the shell regular, circular, twice as broad as the bars; ten to twelve on the half equator. Surface smooth.
Dimensions.—Longer axis of the shell 0.12, shorter axis 0.08; pores 0.006, bars 0.003.
Habitat.—Central area of the Pacific, Station 266, depth 2750 fathoms.
2. Axellipsis lobata, n. sp.
Proportion of the major axis to the minor = 5 : 4. Meshes of the shell irregular, roundish, lobed, with three to six indentations (each mesh formed by the confluence of three to six, commonly four or five, smaller pores); eight to nine meshes on the half equator, these being twice to four times as broad as the bars.
Dimensions.—Longer axis of the shell 0.1, shorter axis 0.08; pores 0.007 to 0.01, bars 0.003.
Habitat.—Tropical zone of the Western Pacific, Station 225, surface.