Shell subspherical, about as long as broad, smooth. Network with regular circular pores, twice as broad as the bars. Columella with two verticils of three ascending branches, prolonged into a stout conical horn of twice the length. Twelve to fifteen conical curved divergent feet, about as long as the shell. The three primary feet are directly connected with the base of the columella. _Dimensions._--Shell 0.08 diameter, horn 0.15 long, feet 0.07 to 0.09 long. _Habitat._--Central Pacific, Station 274, depth 2750 fathoms. Genus 524. _Calpophæna_,[141] Haeckel, 1881, Prodromus, p. 429. _Definition._--#Archiphænida# (vel Monocyrtida multiradiata clausa) with an apical horn and simple internal cavity of the shell without axial columella. The genus _Calpophæna_ and the following closely tied _Archiphæna_ differ from the two preceding genera of Archiphænida in the simple shell cavity, which encloses no columella. They may be derived either from the preceding _Phænocalpis_ by loss of the columella, or directly from the Zygospyrida by reduction of the sagittal constriction and loss of the primary ring. Different subgenera may be distinguished in _Calpophæna_ according either to the number of the feet or to their shape (being simple or branched). {1176}Subgenus 1. _Acrocorona_, Haeckel, 1881, Prodromus, p. 430. _Definition._--Feet simple, not branched nor forked. 1. _Calpophæna tetrarrhabda_, n. sp. Shell subspherical, tuberculate, with subregular circular pores. Apical horn conical, about as long as the shell. Basal plate with a regular cross of four equal cortinar pores, separated by four bars; these are crossed in the sagittal and frontal diameter, and prolonged into four equal conical divergent feet, about as long as the shell. _Dimensions._--Shell 0.1 diameter, horn and feet 0.1 to 0.12 long. _Habitat._--South Pacific, Station 297, depth 1775 fathoms. 2. _Calpophæna hexarrhabda_, n. sp. (Pl. 53, figs. 17, 18). Shell subspherical, rough, with irregular roundish pores. Apical horn conical, shorter than the shell. Basal plate (fig. 18) with three pairs of triangular pores, two larger (cardinal) pores in the middle, two smaller (cervical) at the dorsal, and two intermediate (jugular) at the ventral side. The bars between them are prolonged into six equal cylindrical divergent feet, nearly as long as the shell, provided with a spiny knob at the end. _Dimensions._--Shell 0.09 long, 0.08 broad; horn and feet 0.06 to 0.08 long. _Habitat._--Tropical Pacific, Station 224, depth 1850 fathoms. 3. _Calpophæna ennearrhabda_, n. sp. Shell subspherical, spiny, with irregular, roundish pores. Apical horn cylindrical, longer than the shell. Basal plate with nine collar pores, three larger central alternating with three pairs of smaller peripheral (like Pl. 87, fig. 2). Corona with nine slender cylindrical, slightly curved, divergent feet, somewhat longer than the shell.