Bullmouth Helmet - The Cameo Shell Cypraecassis rufa. Also known as the Red Helmet, the thick shell is popular for use as a base for cameo carvings. It has large blunt tubercles and rows of spirally arranged tubercles. The aperture is narrow and the outer lip is broad. The exterior color is riddish brown with some paler areas. Common to Indo-Pacific with exception of India and Hawaii. Found near coral reefs.