Also known as Frog Shells, these Bursa shells are distinguished by a gutterlide canal or a slit-sided tube, that cuts through the edge of the aperture at its rear end. Some frog shells are moderate in size, while a few are large. These finials average three inches tall. Bursas come in many shapes, some coarsely ornamented with thick ribs, knobs and warty lumps; which gives them the name frog shells. Most frog shells live on sand and coral rubble; commonly found across the Indo-Pacific region. As with all of our finials, the shell is mounted on an independent swivel, so it can be spun to any position.