The genus Stichopodium differs from the preceding genus Podocampe in the fenestration of the three free terminal feet. It agrees in this character with the genus Stichopterium, and may be derived either from this by loss of the lateral ribs, or from the three-jointed Pterocanium by addition of new shell-joints.
1. Stichopodium dictyopodium, n. sp. (Pl. [75], fig. 6).
Shell subcylindrical, in the upper third conical, with six or seven internal annular septa. All seven or eight joints are about equal in length, except the small hemispherical cephalis, which is scarcely half as long, and bears an oblique, conical horn of the same length. Pores small and numerous, regular, circular, quincuncial. The last joint with wide open mouth, and a peristome of three large, triangular, latticed, shovel-shaped, vertical feet.
Dimensions.—Length of the shell (with seven joints) 0.2, breadth 0.11. Length of each single joint about 0.03, of the feet 0.03.
Habitat.—Central Pacific, Station 272, depth 2600 fathoms.
Subfamily 2. Stichoperida, Haeckel, Prodromus, p. 439.
Definition.—Podocampida with the terminal mouth of the shell fenestrated (vel Stichocyrtida triradiata clausa).
Genus 633. Stichopera,[[250]] Haeckel, 1881, Prodromus, p. 439.
Definition.—Stichoperida (vel Stichocyrtida triradiata clausa) with three solid lateral ribs, or three longitudinal combs of spines. Cephalis with a horn.
The genus Stichopera, and the two following genera, represent the small subfamily of Stichoperida, or those triradiate Stichocyrtida in which the terminal mouth is closed by lattice-work. In Stichopera the three radial appendages are either solid lateral ribs or longitudinal combs of spines; the closed basal part of the shell is rounded, not pointed. It may be derived either from Stichopilium by closure of the mouth, or from Lithornithium by increase of the number of the joints.