Seal Gang

A "notorious" gang of modern-day pirates—headquartered in an "underground hideout" on the barren desert island of Vumania—who make a series of desperate attempts to prevent Jimmy Olsen from laying claim to the island and thereby uncovering their secret "base of operations." The Seal Gang is apprehended by Superman in August 1957 (Act No. 231: "Jimmy Olsen, Knight of Metropolis").