Page:Scientific results HMS Challenger vol 18 part 2.djvu/307

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Definition.—Axis of the conical shell curved. Pores circular or roundish.

11. Cornutella curvata, Haeckel.

Cornutella clathrata, var., Ehrenberg, 1854, Mikrogeol., Taf. xxii. figs. 39a, b, c.

Cornutosa clathrata, Haeckel, 1881, Prodromus, p. 427.

Shell slender, conical, with curved axis; the curve lies in one plane and is not spirally convoluted. Pores subregular, circular, of nearly equal size, quincuncially disposed. Horn short, conical.

Dimensions.—Shell 0.1 to 0.15 long, 0.04 to 0.06 broad.

Habitat.—Fossil in tertiary rocks of Sicily (Caltanisetta).

12. Cornutella spiralis, n. sp.

Cornutura spiralis, Haeckel, 1881, Prodromus, p. 427.

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.

Definition.— 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.