This sea snail has a type of shell called a fusiform shell. The size of it can vary, though. The length can vary between 23 mm and 28 mm, and the width can change depending on many things, as most shells are not perfectlysized in some way. The shell of the Borsonia epigona is usually a whitish color, but may vary depending on where you are in the region it is found. The shell is rounded upwards in a spiral, and rough rather that smooth.