length. Thorax and abdomen rounded, without prominent edges. Three basal feet pyramidal, solid, nearly vertical, as long as the thorax. Pores irregular, roundish, in the abdomen large, twice to three times as broad as in the thorax.
Dimensions.—Length of the three joints, a 0.03, b 0.03, c 0.08; breadth, a 0.04, b 0.06, c 0.09.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
3. Lithochytris tripodium, Ehrenberg.
Shell pyramidal, nearly pear-shaped, with two distinct strictures. Length of the three joints = 1 : 2 : 4, breadth = 1 : 2 : 5. Cephalis with a horn of the same length, conical. Thorax and abdomen rounded, without prominent edges. Three basal feet conical, solid, strongly divergent, shorter than the thorax. Pores subregular, circular, twice as broad in the abdomen as in the thorax.
Dimensions.—Length of the three joints, a 0.02, b 0.04, c 0.08; breadth, a 0.03, b 0.05, c 0.1.
Habitat.—Fossil in Barbados.
Subgenus 2. Lithochytridium, Haeckel.
Definition.—Three feet of the abdomen hollow and fenestrated, representing direct protuberances or corner prolongations of the triangular shell-base.
4. Lithochytris galeata, n. sp. (Pl. 67, fig. 16).
Shell pyramidal, with two sharp strictures. Length of the three joints = 1 : 1 : 4, breadth = 1 : 2 : 4. Cephalis subspherical, with an oblique pyramidal horn of the same length. Thorax somewhat larger. Abdomen inflated, with three sharp, prominent edges, which are prolonged over the shell-base into three pyramidal, hollow, and fenestrated feet, longer than the thorax. Pores subregular, circular, twice as broad in the abdomen as in the thorax.
Dimensions.—Length of the three joints, a 0.025, b 0.025, c 0.1; breadth, a 0.025, b 0.05, c 0.1.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
5. Lithochytris pileata, Ehrenberg.
Shell three-sided pyramidal, with deep collar, but indistinct lumbar stricture. Length of the three joints = 2 : 2 : 9, breadth = 3 : 5 : 10. Cephalis with a conical horn of the same length, pear-shaped. Thorax very short and broad. Abdomen inflated, with three sharp, prominent edges, which
