Species: G. muricinum
Scientific Name: Gutturnium muricinum (formerly known as Cymatium muricinum)
The Knobby Triton is a small sea snail that is generally found in shallower waters and not more than 27 meters deep. It ranges from the SE U.S., the West Indies to the Galapagos and Western Pacific Ocean. There are several variations though the one pictured is likely the most common.
Photo source: Conchylinet.com