Habitat.—South Atlantic, off Buenos Ayres, Station 323, depth 1900 fathoms.
6. Trizonium amphibelonium, n. sp.
? Echinosphæra datura, R. Hertwig (partim), 1879, Organismus d. Radiol., p. 54, Taf. iv. figs. 8, 8a.
Central chamber lentelliptical. Lateral girdle lanceolate, nearly one and a half times as long as broad. Four gates subtriangular. Eight to nine pores on the half equator, ten to twelve on the half meridian. Two opposite thin and long spines on the poles of the principal axis, numerous shorter radial spines on the whole surface. Possibly this species is identical with one of the three different Larcoidea which R. Hertwig has described as Echinosphæra datura. His fig. 8, Taf. iv., would be the aspect from the sagittal girdle.
Dimensions.—Length of the central chamber 0.04, breadth 0.025; length of the lateral girdle 0.11, breadth 0.08; height of the gates 0.03, breadth 0.04.
Habitat.—Mediterranean (Genoa), Haeckel, (Messina), R. Hertwig, surface; Tropical Atlantic, Station 348, surface.
7. Trizonium staurobelonium, n. sp.
Central chamber spherical, with two opposite polar beams. Lateral girdle elliptical, one and a half times as long as broad. Four gates transverse-elliptical, half as high as broad. Ten to eleven pores on the half equator, fourteen to fifteen on the half meridian. Four conical radial spines, two on the poles of the lateral, two on the poles of the principal axis.
Dimensions.—Diameter of the central chamber 0.02; length of the lateral girdle 0.075, breadth 0.05; height of the gates 0.014, breadth 0.028.
Habitat.—North Pacific, Station 241, depth 2300 fathoms.