SeaShell News, 3-16-15, Atlantic Deer Cowry, Shelling, Sanibel.
This species is one of the largest cowries. It is quite similar in shape and colour to Macrocypraea cervinetta, but it is much larger. The maximum recorded shell length is 190 millimetres (7.5 in), while minimum length is about 40 millimetres (1.6 in).
The shell is elongated, its basic colour is light brown, with small whitish ocellated spots on the dorsum, like a young fawn (hence the Latin namecervus, meaning ‘deer’). Juveniles have no spots. The dorsum also shows a few transverse clearer bands, and a longitudinal line where the two edges of the mantle meet. The apertural teeth are dark brown. The mantle of the living cowry is dark greyish and completely covered in short fringes.”
Source: Atlantic Deer Cowry.