Network of the shell regular, with circular pores of the same breadth as the thick bars; about eighteen pores on the half meridian, fourteen on the half equator. Surface smooth. Proportion of the three dimensive axes = 2 : 3 : 4.
Dimensions.—Principal axis 0.16, transverse axis 0.12, sagittal axis 0.08; pores and bars 0.004.
Habitat.—Western Tropical Pacific, Station 224, surface.
5. Cenolarcus minimus, n. sp.
Network of the shell subregular, with very small circular pores of the same breadth as the bars; only four pores on the half meridian, three on the half equator. Surface smooth. Proportion of the three dimensive axes = 3 : 4 : 5.
Dimensions.—Principal axis 0.05, transverse 0.04, sagittal axis 0.03; pores and bars 0.006.
Habitat.—Pacific, central area, Station 266, depth 2750 fathoms.
Genus 267. Larcarium,[[306]] n. gen.
Definition.—Larcarida with a simple, lentelliptical latticed shell, without a medullary shell; surface covered with radial spines.
The genus Larcarium differs from Cenolarcus only in the possession of radial spines on the surface of the simple fenestrated lentelliptical shell. These spines are commonly disposed symmetrically, opposite in pairs, either on the poles of the three dimensive axes, or on the poles of certain diagonal axes. Larcarium differs from the similar genera Larcidium, Larnacidium, and Larnacantha by the absence of any medullary shell.