3. Spirocampe polyspira, n. sp.
Shell cylindrical, rough, with twelve joints nearly equal in length, connected in the form of a regular, complete spiral. All windings are at the same distance. Pores regular, circular, three rows on each turning. Cephalis flat, cap-shaped, half as broad as the slightly constricted, not tubular mouth.
Dimensions.—Length of the shell (with twelve joints) 0.24, breadth 0.07; mouth 0.05 diameter.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
Subfamily 2. Stichocapsida, Haeckel, 1881, Prodromus, p. 439.
Definition.—Lithocampida with the terminal mouth of the shell fenestrated (vel Stichocyrtida eradiata clausa).
Genus 653. Cyrtocapsa,[[270]] Haeckel, 1881, Prodromus, p. 439.
Definition.—Stichocapsida (vel Stichocyrtida eradiata clausa) with an apical horn on the cephalis, without basal terminal spine.
The genus Cyrtocapsa and the two following genera represent together the small subfamily of Stichocapsida, or of those Cyrtoidea in which the many-jointed shell bears no radial appendages, and the terminal mouth is closed by a lattice-plate. They have been derived from the Stichocorida by development of such a closing plate. Cyrtocapsa bears an apical horn on the cephalis, and may be derived therefore directly from Eucyrtidium.