This animal is rarely seen alive, the shells are occasionally seen and resemble bird's wings, they are sometimes called Angel's Wings for that reason. The shell is rounded at one end and narrow at the other, the rounded end is heavily ribbed.

Found in soft rock, such as mudstone at mid/low tide.

A filter feeder on phytoplankton.

In the juvenile animal the rounded part of the shell is open so that the foot can extend, acting like an anchor, it contracts making the shell rub against the rock, It is the grinding of this part of the shell that makes the burrow the animal lives in. The burrow is wide and cave-like at the bottom and narrow at the entrance. Once in the burrow the rounded part of the shell seals and the animal remains in the burrow for life. If dislodged they cannot make a new burrow.

Photo Credit: Rod Morris. Photos available from www.rodmorris.co.nz