straight, much longer than the thorax, divergent, and at the broader base irregularly fenestrated, without three larger holes.
Dimensions.—Cephalis 0.05 long, 0.08 broad; thorax 0.07 long, 0.12 broad.
Habitat.—North Pacific, Station 241, depth 2300 fathoms.
3. Acrospyris pyramidalis, n. sp.
Shell three-sided pyramidal, with slight collar stricture. Cephalis campanulate, with deep sagittal stricture and stout ring, armed with a strong pyramidal horn of the same length. Thorax shorter and broader, truncate. Pores irregular, roundish, scarce. Three feet divergent, three-sided pyramidal, as long as the cephalis.
Dimensions.—Cephalis 0.05 long, 0.06 broad; thorax 0.02 long, 0.08 broad.
Habitat.—Fossil in Barbados.
4. Acrospyris macrocephala, n. sp.
Shell spinulate, with deep sagittal and very deep collar stricture. Cephalis very large, nut-shaped, twice as long and broad as the small, truncate, pyramidal thorax. Pores irregular, roundish. Horn spindle-shaped, nearly as long as the cephalis; the three divergent feet are of the same form and size as the horn, and arise as three ribs from the deep collar stricture.
Dimensions.—Cephalis 0.1 long, 0.15 broad; thorax 0.05 long, 0.09 broad.
Habitat.—Fossil in Barbados.
5. Acrospyris fragilis, n. sp.
Shell very thin-walled and fragile, with deep sagittal and collar strictures. Pores very small and numerous, circular. Cephalis nut-shaped, nearly spherical, with a slender bristle-shaped horn of the same length. Basal stricture with two large collar pores only (luminella). Thorax nearly three-sided prismatic, longer than the cephalis, with three parallel ribs, prolonged into three slender, long, bristle-shaped feet.
Dimensions.—Cephalis 0.05 long, 0.06 broad; thorax 0.08 long, 0.06 broad.
Habitat.—North Pacific, Station 244, surface.
Genus 475. Phormospyris,[1] Haeckel, 1881, Prodromus, p. 442 (sensu emendato).
Definition.—Phormospyrida with three basal feet, without apical horn.
The genus Phormospyris has been derived from Acrospyris, its ancestral form, by reduction and loss of the apical horn; it therefore bears to the latter the same relation that Tristylospyris has to the ancestral Tripospyris.
- ↑ Phormospyris = Wicker-basket; φορμός, σπυρίς.
