pyramidal, with three strongly divergent ribs, which are prolonged into three slender conical feet of about the same length. Pores irregular, roundish, of variable size.
Dimensions.—Cephalis 0.032 long, 0.028 broad; thorax 0.34 long, 0.064 broad.
Habitat.—Mediterranean (Messina), Atlantic (Canary Islands), surface.
3. Dictyophimus plectaniscus, n. sp. (Pl. 61, figs. 8, 9).
Shell flat, pyramidal, smooth, with distinct collar stricture. Cephalis hemispherical, with a conical horn of the same length and numerous small regular pores. Thorax flat, triangular, pyramidal, with three widely divergent ribs, which are prolonged into three cylindrical feet of the same length. Thoracic pores fifteen, very large, subregular, roundish, disposed in two transverse girdles, the inner with six, the outer with nine pores; five pores between every two ribs.
Dimensions.—Cephalis 0.04 long, 0.06 broad; thorax 0.08 long, 0.18 broad.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
4. Dictyophimus craticula, Ehrenberg.
Shell flat, pyramidal, very similar to the preceding species, but differing in the rudimentary horn, which is smaller than half the cephalis, and in the length of the three cylindrical feet, which are twice to three times as long as the shell. The nine inferior large pores of the thorax are twice to three times as large as the six superior pores. The basal peristome is commonly thorny.
Dimensions.—Cephalis 0.04 long, 0.05 broad; thorax 0.1 long, 0.2 broad.
Habitat.—Fossil in Barbados.
5. Dictyophimus pyramis, n. sp. (Pl. 61, fig. 16).
Shell regular, pyramidal, with flat collar stricture. Relative length of the two joints = 1 : 4, breadth = 2 : 6. Cephalis hemispherical, with a stout pyramidal horn of the same length. Thorax triangular pyramidal, with three prominent ribs, which are prolonged into three slender pyramidal feet, half as long. Pores small and very numerous, subregular, circular.
Dimensions.—Cephalis 0.03 long, 0.05 broad; thorax 0.1 long, 0.15 broad.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
6. Dictyophimus challengeri, Haeckel.
Shell campanulate, with sharp collar stricture. Relative length of the joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, with a stout pyramidal horn of twice the length, and numerous
