Could anyone tell me, why I can't create Lightning Component Tab on my full sandbox on 16 enterprise edition?

Thanks, Ruslan Kurchenko

Could anyone tell me, why I can't create Lightning Component Tab on my full sandbox on 16 enterprise edition? I just can't see Lightning Component Tab related list in the Setup | Tabs section... So, After creating component I can't use it neither in Lightning Component Tab and in Lightning App Builder too (in the custom components section).

Thanks, Ruslan Kurchenko