Pharus legumen is up to 130mm long and has a characteristic bean-shaped shell. The shell colour ranges from white to light brown and it displays a light olive to yellow periostracum. The right valve has a single cardinal tooth and a short peg-like posterior lateral tooth, whereas the left valve has two elongated and closely spaced cardinal teeth and a single posterior lateral tooth.[4]
Pharus legumen is similar to other species of razor clam of the genus Ensis, Phaxas and Solen. The key feature to identify it is the presence of a ligament in the middle third of the shell.[4]