[1] The ventricose shell of adult Tonna galea is very large, with an average height of 6 inches (150 mm).

[3] The shell is almost diaphanous when young; at that time the transverse ribs of the surface are only indicated by lines of a slightly deeper tint.

[4] The conical spire is formed of six convex, very distinct whorls, loaded externally with wide, flat, slightly raised ribs, separated by narrow and superficial furrows.

The columella is smooth, polished, and forms at the left of the umbilicus a thick rib, marked by transverse striae, which terminates at the emargination of the base.

The external surface of this shell is of a uniform reddish fawn color ; nevertheless the ribs are varied with wide spots or irregular brown and white blotches which are very remarkable.

[5] The animal is of a clear brownish red, without spots, and its tentacles are encircled, towards the point, with a wide reddish-brown ring.

[8] Information on the biology and life history of Tonna galea is scarce, due to the fact that the species has only rarely been studied.