Synopsis of the Genera of Tripocalpida.
I. Subfamily Archipilida.
Basal mouth of the shell a simple wide opening. |
Shell with three lateral ribs or wings, with or without terminal feet. | Three terminal feet. | Apex with a horn, | 496. Tripocalpis. | |||
No apical horn, | 497. Tripodonium. | ||||||
Six to nine or more terminal feet. | No apical horn, | 498. Tripterocalpis. | |||||
No terminal feet. | Apex with a horn, | 499. Trissopilium. | |||||
No apical horn, | 500. Archipilium. | ||||||
Shell without lateral ribs or wings but with three terminal feet. | Feet simple or branched, not latticed. | Apex with a horn, | 501. Tripilidium. | ||||
No apical horn, | 502. Tripodiscium. | ||||||
Feet latticed. | Apex with a horn, | 503. Tridictyopus. | |||||
II. Subfamily Archiperida.
Basal mouth of the shell closed by a lattice-plate. |
Shell in its axis with a free (simple or branched) internal columella, prolonged into an apical horn. | Shell with three free feet, without lateral lattice-wings. | Columella simple, | 504. Euscenium. | |||
Columella branched, | 505. Cladoscenium. | ||||||
Shell with three lateral lattice-wings, connecting the three feet with the horn. | Columella simple, | 506. Archiscenium. | |||||
Columella branched, | 507. Pteroscenium. | ||||||
Shell with simple cavity, without free columella. Three free basal feet. | One apical horn, | 508. Peridium. | |||||
Two or more horns, | 509. Archipera. | ||||||
No apical horn, | 510. Archibursa. |
Subfamily 1. Archipilida, Haeckel, 1881, Prodromus, p. 427.
Definition.—Tripocalpida with the basal mouth of the shell open (vel Monocyrtida triradiata aperta).
Genus 496. Tripocalpis,[1] Haeckel, 1881, Prodromus, p. 428.
Definition.—Archipilida (vel Monocyrtida triradiata aperta) with three lateral ribs prolonged into three terminal feet. Apex with a horn.
The genus Tripocalpis opens the series of Archipilida, or of those Monocyrtida in which the monothalamous shell exhibits a distinct triradial structure, and a simple open mouth, without cortinar lattice. Tripocalpis is probably the most primordial of the Archipilida, and has three lateral ribs, which are prolonged into three free terminal
- ↑ Tripocalpis = Urn with three feet; τρίπους, καλπίς.