The genus _Gorgospyris_ agrees with the three preceding genera in the possession of numerous basal feet, but differs from them in the complete absence of any horns on the coryphal face. It represents therefore the "hornless polypedal Zygospyrida," and may {1070}be derived from _Petalospyris_ by loss of the original apical horn. The feet are commonly numerous, and often form a circle around the margin of the basal plate, similar to the circle of tentacles in many Medusæ (Gorgon). Subgenus 1. _Gorgospyrium_, Haeckel. _Definition._--Feet simple, not branched. 1. _Gorgospyris medusa_, n. sp. (Pl. 87, fig. 1). Shell hemispherical, papillate, with slight sagittal stricture and subregular circular pores. Basal plate with three large collar pores (by mistake not correctly represented in the figure). Ten to twelve slender feet, twice as long as the shell, strongly curved and divergent, of equal length. _Dimensions._--Shell 0.06 long, 0.08 broad; feet 0.1 long. _Habitat._--North Pacific, Station 241, depth 2300 fathoms. 2. _Gorgospyris medusetta_, n. sp. (Pl. 87, fig. 2). Shell misshaped, smooth, with deep sagittal stricture and irregular, roundish pores. Basal plate with three large collar pores, alternating with three pairs of smaller pores. Sixteen to twenty slender feet, about as long as the shell, slightly curved and divergent, of nearly equal length. _Dimensions._--Shell 0.05 long, 0.08 broad; feet 0.05 long. _Habitat._--Central Pacific, Station 274, depth 2750 fathoms. 3. _Gorgospyris ehrenbergii_, Haeckel. _Petalospyris pentas_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 80, Taf. xxii. fig. 11. Shell nut-shaped, smooth, with slight sagittal stricture and unequal circular pores. Basal plate with three large central pores, alternating with three pairs of smaller pores, and with a peripheral circle of smaller pores. Twenty-four to thirty short truncated feet, shorter than half the shell. _Dimensions._--Shell 0.05 long, 0.07 broad; feet 0.02 long. _Habitat._--Fossil in Barbados. 4. _Gorgospyris polypus_, n. sp. (Pl. 87, fig. 3). Shell hemispherical, papillate, with slight sagittal stricture and subregular circular pores. Basal plate with four larger and four alternating smaller pores. Feet sixteen to twenty, slender, carved, divergent; four primary feet larger, twice to three times as long as the shell and the other feet. _Dimensions._--Shell 0.08 long, 0.1 broad; feet 0.1 to 0.2 long. _Habitat._--South Atlantic, Station 332, depth 2200 fathoms. {1071}5. _Gorgospyris eurycolpos_, n. sp. (Pl. 87, fig. 5). Shell nut-shaped, rough, with deep sagittal stricture and irregular, roundish pores; two to three pairs of larger annular pores on each side of the stricture. Basal plate with four large collar pores. Feet eight, short, triangular, vertical, about one-fourth as long as the shell. _Dimensions._--Shell 0.08 long, 0.13 broad; feet 0.02 long. _Habits._--Central Pacific, Station 270, depth 2925 fathoms.