Bowls like these were used to hold kola nuts as offerings of hospitality or as receptacles for the sixteen sacred palm nuts used in divination. This form, with a kneeling female figure with lidded bowl, is known as an Opon Igede Ifa.
This bowl, unusually large, shows no real indication of tribal use and was probably made for the art market.
Another form, with the bowl on top, is known as an Agere Ifa, can be seen on Offering Bowls Page 1.