Cyclostome

Cyclostome is a biological term (from the Greek for "round mouth") used in two different senses:
 * for the extant members of the Agnatha, i.e. the hagfish (Myxini) and the lampreys (Petromyzontidae). This is a paraphyletic group and this usage of the term is deprecated.
 * for the Order Cyclostomatida of bryozoans, tiny animals that live in colonies and form large calcitic skeletons.