Body higher than wide; mouth placed well forward, with slightly wrinkled, thickened lips; rhinophores large, folded; tentacles rather small; eyes not seen; foot elongated, extending to a point behind, its border crimped; swimming lobes wide and almost auricled in front, narrower and united behind, closely inclosing the very large shell; mantle having a large oval opening which exhibits the shell. Excurrent siphon lateral, opening at posterior sinus of shell. Color, a dirty greenish white; border of foot, pleuropodia, and mantle opening intense black, as are the tips of the rhinophores. Length of animal, 20; diameter of mantle opening, 6; length of opening, 6 mm. Shell very large, solid, concave, covered with a rather thick epidermis, which peels on exposure to air; posterior sinus moderate, overhung by the epidermis; apex much incurved, callous, but having no recurved process. Interior calcareous, slightly iridescent, pinkish white, externally straw colored. Length, 13 mm.; breadth, 9 mm.; height, 5 mm. Length of sinus, 5 mm.