A helical shell with distinct lines between the rounded whorls, up to 3 cm high by 3 cm wide. The last whorl of the shell occupies about 90% of the shell, ending in the large aperture. The last whorl bears one row of brown marks. The shell bears a distinct, usually rounded umbilicus. Shell buff or paler yellow in colour. The head bears a short snout and two flattened tentacles. The foot is enlarged and partially covers the shell and head in mobile animals. The foot acts as a plough-share as the animal moves through the soft substrata on which it lives. The flesh of the animal is cream or yellow in colour with red-brown marks.Euspira catena is very similar to Alder's necklace shell Polinices pulchellus but with some differences. Euspira catena is a much larger snail, the spire is more obvious in Euspira catena and the whorls are shouldered and have distinct joins (sutures). The shell of Euspira catena is much paler in colour than Polinices pulchellus and has only a single row of brown markings on the last whorl. However, Euspira catena and Polinices pulchellus have similar distributions and habitat preferences and are, therefore, likely to be found together.

 Egg capsules are laid in a characteristic open collar-shaped mass of jelly and sand grains (Graham, 1988, Hayward et al., 1996). The collar is ca 7.5 cm in diameter with eggs capsules arranged in regular lines within the collar but bulging slightly on its surface. Breeding occurs in spring and early summer (Graham, 1988).