The genus Euphysetta agrees with the preceding Medusetta in the possession of four articulate feet; but whilst these in the latter are of equal size and similar shape, in the former a single odd foot only is developed, and very large, whilst the three others are rudimentary and very small. Euphysetta exhibits therefore the same relation to Medusetta that the Euphysidæ (Euphysa, Steenstrupia, &c.) bear to the Sarsiadæ (Codonium, Sarsia), among the Hydromedusæ (compare my System der Medusen, 1879, vol. i. p. 12).
1. Euphysetta staurocodon, n. sp. (Pl. [118], fig. 2).
Shell ovate, nearly as broad as long, smooth, with an oblique, slender, conical, apical horn of the same length. The larger odd foot cylindrical, curved, somewhat longer than the shell, with three diverging branches at the distal end. The three smaller feet very short, representing the form of a regular rectangular cross.
Dimensions.—Length of the shell 0.15, breadth 0.14.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
2. Euphysetta hybocodon, n. sp.
Shell ovate, one and one-third times as long as broad, smooth, with an oblique, stout, conical horn of half the length. The larger odd foot cylindrical, curved, twice as long as the shell, with a few pairs of short lateral branches and forked distal end. The three smaller feet half as long as the shell, thorny.
Dimensions.—Length of the shell 0.16, breadth 0.12.
Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.
3. Euphysetta amphicodon, n. sp. (Pl. [118], fig. 3).