This adê, or crown, or headdress, would seem to represent the orisha Yemanja. Yemanja is a goddess in the candomble religion, which has roots in Yoruba culture, and was brought to South America by African slaves. Yemanja is considered to be the goddess of the seas, and the earth mother in candomble culture. The blue color of this adê provide the strongest indicator of it being representative of Yemanja; the blue can variously represent security, safety, intelligence, and unity. This adê would be worn by a participant in festivals honoring Yemanja, typically the last day of each year. The adê and other representational clothing would be worn for dancing and other festivities commemorating Yemanja to usher in a new year with her blessings.
Dr. Turner would likely have acquired this adê during his visit to Bahia in the early 1940s.