13. The Federal taxes, the net proceeds of which are to be shared with the provinces, fall into two groups:

(1) taxes, the sharing of the net proceeds of which has been made obligatory by the Constitution viz., income-tax and jute export duty;

(2) taxes, the sharing of the net proceeds of which has been left to be determined by the Federal Legislature viz, Central Excises including duty on salt, and export duties except on jute and jute products. The Central Legislature has levied certain taxes under these heads, but has not provided for giving any share to the provinces.