Cavolinia inflexa (Lesueur, 1813) forma imitans (Pfeffer, 1880)
Shell transparent with flat dorsal side and slightly convex ventral side. Caudal portion of shell behind lateral spines shorter than in forma inflexa and more strongly curved dorsally; otherwise quite similar to the latter. Sculpture of faint growth lines. Lateral spines well-developed, projecting from middle of shell, not bending as far caudally as in forma labiata. Caudal spine long. Upper aperture lip rather large, separated from rest of ventral side by conspicuous incision. Shell length: 8 mm.