(Pallas, 1774)
Description
— Aggregate form with rather large, prismatic body. Test very tough. Posteriorly asymmetrical and with a deep groove both dorsal and ventral. At the posterior end is a single, acentric projection. Very clear and wide muscle bands; all are ventrally interrupted, only M1 is also dorsally interrupted. M4 and M5 are dorsally united.
— Solitary form with large body, that is conspicuously prismatic; tough and firm test. Muscle band s are extremely wide, almost touching each other laterally. All muscle bands are dorsally and ventrally interrupted. The posterior end of the body with a marked pointed projection. The stolon encircles the intestine.
Size
Length of aggregate form: up to 60 mm; length of solitary form: up to 50 mm.
Depth range
Remark
Soestia zonaria recently became the new name for Iasis zonaria (Kott, 1998)
Distribution in the North Sea
Possibly occurring in the northern North Sea.
World distribution
Cosmopolitan, eurythermic species from all oceans, except for Antarctic and Arctic.