Pteraster tesselatus is commonly called the cushion star because of its inflated appearance. The disc is high, averaging 35mm in height, and the rays, usually five, are short and thick, causing the cushion star to appear pentagonal in shape. The outer membrane is thick and spongy and has regular reticulation 5 to 8mm across. The surface of the membrane varies greatly in texture from smooth to slimy and rough. On the rays, combs are composed of 5 to 7 spines arranged in a fan-shaped manner. In between the rows of combs lie two rows of large tube feet ending in sucking devices. The last ten pairs of tube feet of each ray have no sucking devices and appear to be tactile. At the end of each ray, there is a red eye spot protected by short spines. A large oral opening at the center of the disc is surrounded by a sphincter-like membrane. The colors of the cushion star include cream, tan, yellow, orange, and a gray purple (Zintheo,1946).