Cortical shell without peculiar spines or hollow fenestrated tubes on both poles of the main axis.
Cortical twin-shell simple
Medullary shell simple,
155. Cyphanta.
Medullary shell double,
156. Cyphonium.
Cortical twin-shell double or triple; medullary shell double.
Cortical shell double,
157. Cypassis.
Cortical shell triple,
158. Cyphocolpus.
Cortical shell simple, with peculiar spines or hollow fenestrated tubes on both poles of the main axis.
Two opposite polar spines (or bunches of spines).
Medullary shell simple,
159. Cyphinus.
Medullary shell double,
160. Cyphinidium.
Two opposite hollow fenestrated polar tubes.
Medullary shell simple,
161. Cannartiscus.
Medullary shell double,
162. Cannartidium.
Genus 155. Cyphanta,[[194]] n. gen.

Definition.—Cyphinida with simple cortical shell and simple medullary shell, without polar spines or tubes.

The genus Cyphanta is the most simple of all Cyphinida, and can be regarded as the common ancestral form of this family. It may be derived phylogenetically from Druppula by a ring-like constriction in the equatorial plane of the ellipsoidal cortical shell, or from Artiscus by secondary formation of a central (spherical or ellipsoidal) medullary shell.

Subgenus 1. Cyphantella, Haeckel.

Definition.—Surface of the cortical shell smooth, without spines or thorns.

1. Cyphanta colpodes, n. sp.

Cortical shell thin walled, with smooth surface; its pores regular, hexagonal, three to four times as broad as the bars; ten to twelve on the half meridian, seven to eight on the half equator. Medullary shell spherical, its diameter one-third of the equatorial axis of the cortical shell. (The cortical shell of this species is nearly identical with the central half of the cortical shell of Panartus diploconus, Pl. [40], fig. 1.)

Dimensions.—Main axis of the cortical shell 0.12, equatorial axis 0.07; meshes 0.013; bars 0.003; diameter of the medullary shell 0.025.

Habitat.—South Pacific, Station 285, depth 2375 fathoms.