Sentence:  The actual delivery of the goods is then effected by any person bearing an order from the importer, called a merchant's order, and addressed to the warehouse-keeper, upon the presentment of which the warehouseman delivers the goods, having previously obtained the signature of the <WSD>locker</WSD> to it as a proof that the duties have been paid ... 
Meaning of the word marked with <WSD> tags:  A customs officer who guards a warehouse.