Scientific Name: Cypraecassis rufa Common Name: Bullmouth Helmet Shell Size: Typically ranges from 10 to 15 cm in length, but can sometimes be larger. Width and height can vary, with the shell having a substantial, solid feel. Shape: The shell has a thick, heavy structure with a distinctive, helmet-like appearance. The opening (aperture) is wide and extends the length of the shell, with the outer lip being thick and rolled. The spire is low, with a somewhat flattened top. Color: The outer surface is usually a reddish-brown or orange-brown color, often with streaks or spots of white or cream.