Borgert
Diagnosis: Shell with dissimilar curving surfaces, flattened on one side, in side view nearly circular or subcircular, smooth. On aboral pole 4 chambered, weakly divergent, oval legs, shorter than (often scarcely half as long as) shell diameter, distally straight or bent slightly inward, with longer or shorter lateral branch about in the middle or toward distal end. Terminal and lateral branches longer on one side off the shell. Sometimes 1 or 2 short thorns on rim of mouth.
Length: 0.065-0.085 mm.