Borgert
Diagnosis: Shell ovoid, weakly laterally compressed, surface with a number (usually 14-16) more or less prominent, equally spaced, longitudinal, meridional ribs, usually restricted to the widest part of the shell, lacking on the aboral dome and the oral area. Four strong, divergent, distally pointed legs, connected in pairs by narrow threads into two lateral arches. Unbound pair of legs on one side closer together and longer than the opposite pair. Outer side of legs branched, with longest, thickest branches usually toward the mouth. Base of each leg with thin bristle directed obliquely outwards, and often 3-5 narrow, short spines on rim of the mouth within the arches.
Takahashi and Honjo (1981) distinguished an Atlantic form with ovoid shell and feet extending obliquely and bent abruptly at the branching joint.
Length: 0.065-0.075 mm.