Page:Scientific results HMS Challenger vol 18 part 2.djvu/792

1668 small Medusæ (e.g., Codonium, Tiara, Sarsia, &c.). This similarity is the greater, as usually the four feet are elegantly curved and the entrance in the shell-cavity partly closed by a marginal diaphragm, comparable to the velum of the Craspedotæ or Hydromedusæ. In all the species observed the apex of the shell bears a slender vertical or curved spine, comparable to the apical horn of the. In most species the feet bear on their convex outside a series of teeth or branches, which are also alveolate.

1. Medusetta codonium, n. sp. (Pl. 120, fig. 1).

Shell ovate, smooth, twice as broad as the constricted mouth. Apical horn about as long as the shell, nearly straight, smooth. Feet cylindrical, smooth, irregularly curved, about as long as the shell.

Dimensions.—Length of the shell 0.08, breadth 0.05.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

2. Medusetta tiara, n. sp.

Shell campanulate, smooth, about as long as broad, and three times as broad as the constricted mouth, which is surrounded by a horizontal broad ring, like the velum of a Hydromedusa. Apical horn conical, straight, half as long as the shell. Feet divergent, irregularly curved, twice as long as the shell.

Dimensions.—Length of the shell 0.07, breadth 0.06.

Habitat.—North Atlantic (Færöe Channel), John Murray, surface.

3. Medusetta minima, n. sp.

Shell slenderly ovate, smooth, about twice as long as broad, twice as broad as the constricted mouth. Apical horn straight, vertical, of the same length. Feet somewhat longer, very thin, slightly curved at the base, in the distal half nearly parallel and descending vertically.

Dimensions.—Length of the shell 0.06, breadth 0.03.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

4. Medusetta quadrigata, n. sp. (Pl. 120, fig. 2).

Shell ovate, campanulate, smooth, little broader than the wide open mouth. Apical horn longer than the shell, more or less curved, smooth. Feet cylindrical, about as long as the shell, strongly curved and somewhat spirally revoluted, with a series of short curved teeth on the abaxial margin.

Dimensions.—Length of the shell 0.07 to 0.09, breadth 0.04 to 0.06.

Habitat.—North Pacific (off Japan), Stations 231 to 237, surface.