The Panama Pacific Exposition Commemorative $50 piece was one of a group of 5 coins minted to mark the celebration of the opening of the Panama Canal in 1915. In addition to the massive $50 gold pieces there was a silver half dollar and Gold $1 and $2 1/2 pieces of standard size for the denomination.
The set of commemoratives was authorized by Congress through Public Law No. 63-233 on January 16, 1915. The $50 pieces were designed by Robert I. Aitken, a New York artist.
The design of the Octagonal piece is very similar to the design used on the round pieces with a few exceptions. The design is also slightly reduced in size to fit the slightly reduced diameter.
The Obverse design features the head of the goddess Minerva with a Corinthian style helmet including a Horsehair comb and an engraved wreath of laurel leaves resting back on her head. The date is found in Roman numerals (MCMXV) in an arch on the lower right. The inscription “IN GOD WE TRUST “is above Minerva’s brow in the upper right. The entire central portrait is enclosed in a ring of beads. Outside the ring is the inscription “UNITED STATES OF AMERICA” and “FIFTY DOLLARS” which completely encircle the coin. The words are separated by dots. On the Octagonal piece the design in completed by the inclusion of eight stylized dolphins in the angle formed by inscribing an outer circle within the octagon. These Dolphins “circling” the design are said to represent the continuous flow of water and commerce form the Atlantic to the Pacific represented the recently completed canal.
The reverse design has a similar format. The central design feature is an owl, perched on a pine bough complete with four pinecones and multiple sprigs of pine needles. The inscription “E PLURIBUS UNUM” is centered to the right of the owl with dots at the beginning and end (though none between the words). These central elements are surrounded by the same ring of beads used on the obverse. Outside this ring are the inscriptions “PANAMA-PACIFIC EXPOSITION” and “SAN FRANCISCO” in a single line of text circling the entire rim. Again the words are separated by dots. The dolphin motif in the angles is continued here as wall.