For extraordinary heroism in battle, engagements of Vera Cruz, 21 and 22 April 1914. Posted on the roof of the Terminal Hotel and landing, Ens. McDonnell established a signal station there day and night, maintaining communication between troops and ships. At this exposed post he was continually under fire. One man was killed and 3 wounded at his side during the 2 days' fighting. He showed extraordinary heroism and striking courage and maintained his station in the highest degree of efficiency. All signals got through, largely due to his heroic devotion to duty.