5. Lamprospyris spenceri, n. sp.
Shell slender, ovate, very similar to the preceding species; differing from it in the larger cupola, which is as long as the cephalis and thorax together. The three feet are much shorter and weaker, more divergent. This differs from all four preceding species in the possession of a large double apical horn; the two horns are strong, pyramidal, straight, strongly divergent, and as long as the cupola.
Dimensions.—Length of the shell (without the appendages) 0.3, breadth 0.2, ring 0.05 long.
Habitat.—Central Pacific, Station 272, depth 2600 fathoms.
Subfamily 2. Perispyrida, Haeckel, 1881, Prodromus, p. 443.
Definition.—Androspyrida without free basal feet, with three distinct joints separated by two parallel transverse strictures.
Genus 481. Amphispyris,[[99]] Haeckel, 1881, Prodromus, p. 444.
Definition.—Androspyrida without free basal feet, with three distinct joints, separated by two transverse strictures; lattice-work of the shell only complete in the frontal ring, with large open holes on the ventral and dorsal face.
The genus Amphispyris and the two following genera arising from it, represent together the peculiar small subfamily of Perispyrida. This may have originated directly from Toxarium (family Tympanida, Pl. [88], fig. 1; Pl. [93], figs. 18-20), the large holes between its arches and rings becoming filled up by lattice-work; in Amphispyris this intercalated network remains incomplete on the ventral and dorsal faces, whilst in Tricolospyris it becomes complete, and in Perispyris spongy.