The genus _Zygospyris_ and the following three genera represent together the peculiar subfamily of Therospyrida. These always possess four basal feet, like the Tetraspyrida; but whilst in the latter group two feet are sagittal, and two lateral, in the Therospyrida there are no sagittal feet at all, but the four feet are opposed in two lateral pairs; the anterior pair corresponds to the pectoral, the posterior to the tergal feet of the Hexaspyrida and Pentaspyrida; from these latter the Therospyrida have been derived by loss of the sagittal feet. 1. _Zygospyris quadrupes_, n. sp. Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores irregular roundish, on each side of the ring two pairs of larger pores. Apical horn conical, straight. Four feet equal, straight, divergent, conical, about as long as the shell and the horn. _Dimensions._--Shell 0.08 long, 0.11 broad; horn and feet 0.1 long. _Habitat._--South Atlantic, Station 335, depth 1425 fathoms. {1056}2. _Zygospyris equus_, n. sp. (Pl. 83, fig. 16). Shell subspherical, rough, with slight sagittal stricture. Pores small and numerous, subregular circular; no larger annular pores. Apical horn cylindrical, half as long as the shell. Two pectoral feet somewhat smaller than the two tergal feet, about as long as the shell, slightly divergent, cylindrical. The distal ends of the feet and of the horn form an ovate, dimpled and spinulate cone. _Dimensions._--Shell 0.06 long, 0.09 broad; horn 0.04 long, feet 0.06 long. _Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. Genus 460. _Elaphospyris_,[78] Haeckel, 1881, Prodromus, p. 442. _Definition._--#Zygospyrida# with two pairs of lateral feet and three coryphal horns. The genus _Elaphospyris_ differs from the preceding _Zygospyris_, its ancestral form, in the possession of three coryphal horns (one odd apical and two paired frontal horns), and therefore bears to it the same relation that _Triceraspyris_ does to _Tripospyris_ among the Tripospyrida. Subgenus 1. _Giraffospyris_, Haeckel, 1881, Prodromus, p. 442. _Definition._--Feet simple, not branched nor forked. 1. _Elaphospyris heptaceros_, Haeckel. _Ceratospyris heptaceros_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. xx. fig. 2. _Giraffospyris heptaceros_, Haeckel, 1881, Prodromus, p. 442. Shell nut-shaped, tuberculate, with slight sagittal stricture and subregular circular pores. Basal plate with four large pores. Apical horn small, conical, shorter than the two curved lateral horns, which are as long as the shell. Caudal and sternal feet small, conical, straight. Two pectoral feet slender, divergent, S-shaped, about as long as the shell. _Dimensions._--Shell 0.05 long, 0.07 broad; horns and feet 0.02 to 0.08 long. _Habitat._--Fossil in Barbados. 2. _Elaphospyris capricornis_, n. sp.