Tonna masculosa

Tonna masculosa:

Partridge Shell. About 5 or 6 inches high, 4 or 5 whirls, sutures impressed. Shell thin and inflated, spire short and with pointed apex. Aperture large, outer lip thin and sharp, slightly crenulate at edge. Sculpture of widely spaced encircling grooves. Colour pale to rich brown, heavily mottled with darker shades and bearing crescent-shaped patches of white, so the surface does indeed remind one of the plumage of a partridge. Moderately deep water.