(which genus contains also a number of other Prunoidea), partly by me (1862) as Didymocyrtis. Both names are inadequate, as allusions to quite different families of Nassellaria, but may be retained as significations of subgeneric divisions. Cyphonium differs from Cyphanta by the double medullary shell, which is either spherical or lenticular.
Subgenus 1. Ommatospyris, Ehrenberg (partim).
Definition.—Surface of the cortical shell smooth, without thorns or spines.
1. Cyphonium coscinoides, n. sp.
Cortical shell thin walled, with smooth surface; pores regular, hexagonal, three to four times as broad as the bars; five to six on the half meridian, eight to nine on the half equator of each chamber. Medullary shells both spherical. (The cortical shell of this species is nearly the same as that of Cyphanta colpodes, and as the middle part of the cortical shell of Panartus diploconus, Pl. 40, fig. 1.)
Dimensions.—Main axis of the cortical shell 0.11, equatorial axis 0.06; greatest breadth of the chambers 0.08; pores 0.013, bars 0.003.
Habitat.—North Pacific, Station 244, surface.
2. Cyphonium virgineum, n. sp. (Pl. 39, figs. 12, 12a).
Cortical shell thick walled, with smooth surface (sometimes a little rough with very small thorns); pores subregular, circular, with hexagonal elevated frames, about as broad as the bars; ten to twelve on the half meridian, sixteen to eighteen on the half equator of each chamber. Medullary shells (fig. 12a) both spherical. (Sometimes, as in the figured specimen, the shell is somewhat irregular, an individual abnormality.)
Dimensions.—Main axis of the cortical shell 0.13 to 0.15; equatorial axis of the structure 0.08 to 0.09, of each chamber 0.1 to 0.12, pores and bars 0.005 to 0.007.
Habitat.—Pacific, western tropical part, Station 225, depth 4475 fathoms.
3. Cyphonium ethmarium, n. sp.
Cortical shell thin walled, with quite smooth surface; pores subregular, circular (without hexagonal frame), twice as broad as the bars; nine to ten on the half meridian of each chamber, sixteen to eighteen on its half equator. Medullary shells both spherical. (This species resembles the proximal internal chambers of Peripanartus atractus, Pl. 40, fig. 7.)
Dimensions.—Main axis 0.13, equatorial axis 0.07; greatest breadth 0.09; pores 0.006, bars 0.003.
Habitat.—Equatorial Atlantic, Station 347, surface.
