Picture is an example; yours will be similar.
Additional information: These currencies were used throughout Nigeria and neighboring countries for more than 300 years. They are probably a middle period British Manilla called "Onoudu" . Many of these currencies were widely used from the sixteenth century, when the Portuguese cast huge quantities and used them to trade in West Africa.
Recommended Reading: See Schaedler's EARTH AND ORE--2500 YEARS OF AFRICAN ART IN TERRA-COTTA AND METAL.