5. Larcidium dodecanthum, n. sp. (Pl. [50], figs. 8, 8a).
Cortical shell rough, with irregular network; pores roundish, twice to four times as broad as the bars; about twelve to fourteen on the half meridian, eight to ten on the half equator. Proportion of the three axes = 2 : 3 : 4. Medullary shell lentelliptical, one-third as large as the cortical, connected with it by twelve thin radial beams, which are prolonged outside into twelve strong conical radial spines, about half as long as the breadth of the shell.
Dimensions.—Length of the cortical shell 0.14, breadth 0.1, thickness 0.07; pores 0.008 to 0.015, bars 0.004; medullary shell 0.04 to 0.05.
Habitat.—South Pacific, Station 288, surface.
6. Larcidium polyacanthum, n. sp.
Cortical shell spiny, with irregular network; pores roundish, once to twice as broad as the bars; about ten to twelve on the half meridian, six to eight on the half equator. Proportion of the three axes = 1 : 2 : 3. Medullary shell lentelliptical, half as large as the cortical shell, connected with it by numerous (twenty to twenty-five) radial beams, which are prolonged outside into three-sided pyramidal spines, about as long as the breadth of the shell.
Dimensions.—Length of the cortical shell 0.18, breadth 0.12, thickness 0.06; pores 0.01 to 0.015, bars 0.008; medullary shell 0.03 to 0.09.
Habitat.—North Pacific, Station 244, depth 2900 fathoms.
Subfamily 3. Spongolarcida, Haeckel.
Definition.—Larcarida with spongy lentelliptical shell (with or without enclosed medullary shell).