Habitat.—Fossil in Barbados.
2. Anthocyrtoma alterna, n. sp.
Shell pear-shaped, smooth, with distinct collar stricture. Length of the two joints = 1 : 5, breadth = 1 : 6. Cephalis hemispherical, with a slender conical horn of twice the length. Abdomen inflated, subglobular, with regular, circular, hexagonally framed pores, three times as broad as the narrow, constricted mouth. Six feet conical, smooth, somewhat divergent, alternating, of different sizes; the three larger (perradial) half as long as the shell, and twice as long as the three smaller (interradial). (Similar to Anthocyrtis ventricosa.)
Dimensions.—Cephalis 0.03 long, 0.04 broad; thorax 0.15 long, 0.18 broad.
Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.
Genus 566. Anthocyrtis,[[183]] Ehrenberg, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, 1847, p. 54.
Definition.—Sethophormida (vel Dicyrtida multiradiata aperta) without thoracic ribs, with nine terminal feet around the mouth. Cephalis free, with an apical horn.
The genus Anthocyrtis (in the original definition of Ehrenberg) contained all Dicyrtida without thoracic ribs, with terminal feet. We here restrict the definition to those Sethophormida in which the number of free terminal feet is constantly nine (three primary perradial and three alternate pairs of secondary interradial feet). Anthocyrtis may be derived either directly from Patagospyris by loss of the sagittal ring, or from Lychnocanium by interpolation of three secondary feet.
Subgenus 1. Anthocyrtella, Haeckel.
Definition.—Feet of the peristome-corona divergent, their basal distance less than their terminal distance.