Clan is exogamous division of a tribe, and the members of which are held to be related to one another by some common ties, maybe common ancestors, totem, territory. Vidyarthi 1976.
Lineage is an extended unilateral kinship group descended from a common ancestor usually five or six generations back. The person is real not myth Lowie 1950.
Size, ancestor, lineage subset of clan.
They play role in deciding marriage, political functions, religious functions, economic. Tiv of Nigeria fight it on the side of the lineage. In India lineage and clan are exogamous units.