[1] The genus is characterised by a shell which is globose, convolute, and planispiral (symmetrically coiled).

The shell of Bellerophon superficially resembles that of a miniature cephalopod (e.g. Nautilus or an ammonite), except that septa are lacking.

Many specimens of Bellerophon show something resembling a "waterline" about halfway up the shell, suggesting that a large amount of the mantle and foot were exposed and covered the outside of the shell, as in the extant Cypraeidae and Naticidae.

These animals were probably quick moving (for gastropods), relying on speed to avoid predators and, when this was not possible, withdrawing deeply into the shell.

Another view is that some Bellerophontids, including Bellerophon, were torted gastropods, but that others were untorted forms.