Shell spiny, ovate, inflate in the apical half. Pores irregular polygonal, four to eight times as broad as the bars. Peristome constricted, half as broad as the shell, with nine slender divergent feet, which like the apical horn are curved, twice to three times as long as the shell and five to ten times as long as the numerous bristles of the surface. _Dimensions._--Shell 0.08 long, 0.06 broad; feet 0.15 to 0.25 long. _Habitat._--Central Pacific, Station 271, depth 2425 fathoms. 7. _Halicalyptra castanella_, n. sp. Shell spiny, nearly spherical. Pores irregular roundish. Peristome constricted, scarcely one-third as broad as the shell, with twelve to twenty slender, widely divergent feet, which like the horn are irregularly curved, and longer than the shell. (Very similar to certain forms of the Phæodarium _Castanella_, Pl. 113, fig. 2.) _Dimensions._--Shell 0.13 diameter, feet 0.15 to 0.18 long. _Habitat._--Central Pacific, Station 272, depth 2600 fathoms. Genus 520. _Carpocanistrum_,[137] n. gen. _Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) without radial ribs in the wall of the campanulate or ovate shell. Mouth with a corona of radial feet. Apex without horn. The genus _Carpocanistrum_ differs from the similar preceding _Halicalyptra_ in the loss of the apical horn. It is very nearly related to the Dicyrtid _Carpocanium_ and may be easily confounded with it. But in the latter the uppermost part of the shell-cavity includes a rudimentary cephalis with a cortinar septum, whilst in _Carpocanistrum_ {1171}the cephalis is entirely lost, and the inner cavity quite simple. The number of the feet of the peristome is from nine to twenty, sometimes more. The mouth is commonly more or less constricted. 1. _Carpocanistrum novenum_, n. sp. Shell ovate, smooth, one and a third times as long as broad. Pores regular circular, hexagonally framed, three times as broad as the bars, eight to ten on the greatest breadth of the shell. Peristome strongly constricted, one-third as broad as the shell, with nine large ovate lamellar, slightly convergent feet. _Dimensions._--Shell 0.08 long, 0.06 broad; mouth 0.02 broad. _Habitat._--South Atlantic, Station 325, surface. 2. _Carpocanistrum flosculum_, n. sp. (Pl. 52, fig. 9). Shell campanulate, rough, thick-walled, of equal breadth and length. Pores regular circular, of the same breadth as the bars, twelve to fifteen on the greatest breadth of the shell. Peristome slightly constricted, with twelve elegant lanceolate, nearly vertical, a little convergent feet. _Dimensions._--Shell 0.07 long, 0.07 broad; mouth 0.05 broad. _Habitat._--Equatorial Atlantic, Station 347, surface. 3. _Carpocanistrum giganteum_, n. sp.