Shell slender, conical, nearly cylindrical, very long, spirally contorted; its axis is an ascending spiral line with two or three windings, widely distant. Pores irregular, square, small and numerous.
Dimensions.—Shell 0.2 to 0.25 long, 0.05 to 0.08 broad.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
Genus 527. Cornutanna,[[144]] Haeckel, 1881, Prodromus, p. 427.
Definition.—Archicorida with conical shell, gradually dilated towards the wide open mouth. Apex without horn.
The genus Cornutanna has the same simple conical shell as the preceding Cornutella, but differs from it in the total absence of an apical horn. It bears therefore to the latter the same relation that Cyrtocalpis does to Archicorys. It may be derived from Sethoconus by complete reduction of the cephalis and its horn.
1. Cornutanna orthoconus, n. sp.
Shell slender, conical, with straight axis and straight outlines. Pores subregular, circular, quincuncially disposed in nine to twelve alternating longitudinal series, gradually increasing in size towards the mouth.
Dimensions.—Shell 0.1 to 0.12 long, 0.03 to 0.04 broad.
Habitat.—Central Pacific, Stations 270 to 274, surface.