Schröder
Diagnosis: Shell ellipsoidal, with wall of thick outer and thin inner layer, outer layer with faint longitudinal striae and less distinct horizontal striae. Oral opening wide, with 3 small solid legs and one chambered leg, smaller legs with an accessory thorn, large leg about as long as shell, with distal thorn-like accessory branch. Stout spine, often short, at aboral pole, usually erect, sometimes tilted ventrally.
Length: 0.06-0.08 mm.