Shell nut-shaped, spiny, with slight sagittal stricture and numerous small circular pores. Basal plate with four large pores. Three horns slender, simple, about as long as the shell, the middle one straight, the two lateral curved. Four feet of nearly equal size, slender, curved, divergent, simple, twice as long as the shell and the horns. _Dimensions._--Shell 0.07 long, 0.09 broad; horns 0.08 long, feet 0.15 long. _Habitat._--Central Pacific, Station 274, depth 2750 fathoms. {1057}Subgenus 2. _Corythospyris_, Haeckel, 1881, Prodromus, p. 443. _Definition._--Feet branched or forked. 3. _Elaphospyris damaecornis_, n. sp. (Pl. 84, fig. 10). Shell flat and broad, nearly triangular, with slight sagittal stricture and irregular roundish pores; two very large pores on the frontal and on the occipital face, opposite on both edges of the broad sagittal ring. Basal plate with four large central and several smaller lateral pores. Three horns about half as long as the shell, with two to six irregular branches. Four feet of equal size, about as long as the shell, divergent, forked, with four to six irregular terminal branches. (The shell in fig. 10 is seen from the apical side.) _Dimensions._--Shell 0.09 long, 0.13 broad; horns 0.05 long, feet 0.1 long. _Habitat._--Indian Ocean, Cocos Islands, Rabbe, surface. 4. _Elaphospyris cervicornis_, n. sp. (Pl. 86, fig. 13). Shell polyhedral, spiny, with deep sagittal stricture and a small number of large roundish pores; two pairs of large pores on each side of the ring. Basal plate with four pores. Three large horns as long as the shell arise from the apex between smaller conical spines; the middle odd horn simple, the two lateral each with a pair of branches. Two pectoral feet very large, divergent, with broad and irregular distal ramification, twice as long as the shell and as the two tergal feet, which are less branched. (Fig. 13 exhibits the shell from the dorsal side.) _Dimensions._--Shell 0.09 long, 0.11 broad; horns and smaller feet 0.07 to 0.09 long; pectoral feet 0.16 long. _Habitat._--Central Pacific, Station 271, depth 2425 fathoms. 5. _Elaphospyris alcicornis_, n. sp. (Pl. 86, fig. 12). Shell nut-shaped, spiny, with sharp sagittal stricture and large roundish pentagonally framed pores; three pairs of larger pores on each side of the ring. Basal plate with four larger and four alternate smaller pores. There arise from the apex, between smaller spines, three large, divergent, pyramidal horns, which are nearly as long as the shell, and connected by an arched frontal bridge. Two pectoral feet very large, divergent, prismatic, longer than the shell, and at the distal end with a bunch of thick spines. Two tergal feet half as long and thick, simple (in the figure hidden behind the large pectoral feet). _Dimensions._--Shell 0.09 long, 0.11 broad; horns and smaller feet 0.06 long, pectoral feet 0.12 long. _Habitat._--Central Pacific, Station 266, depth 2750 fathoms.