1. Larnacalpis lentellipsis, n. sp. (Pl. [50], figs. 2, 2a, 2b).
Cortical shell with thorny surface and irregular network; pores roundish, twice to four times as broad as the bars; about sixteen on the half meridian, twelve on the half equator. Proportion of the three dimensive axes = 2 : 3 : 4. Medullary shell one-third as large as the cortical, with four elliptical internal gates, connected with it by two opposite beams in the principal axis and by two latticed wings in the transverse axis; therefore between the two shells are four large kidney-shaped gates, halved by the polar beams (as in Octopyle).
Dimensions.—Length of the cortical shell (or principal axis) 0.14, breadth (or transverse axis) 0.11, height (or sagittal axis) 0.07; pores 0.01 to 0.02, bars 0.005; length of the medullary shell 0.05, breadth 0.04, height 0.03.
Habitat.—Pacific, central area, Station 273, depth 2600 fathoms.
2. Larnacalpis phacodiscus, n. sp.
Cortical shell with thorny surface and regular network; pores circular, twice as broad as the bars; about ten on the half meridian, eight on the half equator. Proportion of the three axes = 2 : 2.5 : 3. Medullary shell half as large as the cortical, with four kidney-shaped internal gates.
Dimensions.—Length of the cortical shell 0.13, breadth 0.11, height 0.09; pores 0.012, bars 0.006; length of the medullary shell 0.06, breadth 0.045, height 0.03.
Habitat.—North Pacific, Station 253, depth 3125 fathoms.
3. Larnacalpis macrococcus, n. sp.
Cortical shell with spiny surface and regular network; pores circular, small, of the same breadth as the bars; about twenty-two on the half meridian, nineteen on the half equator. Proportion of the three axes = 2 : 3 : 4. Medullary shell two-thirds as large as the cortical, with four wide internal semicircular gates.