Dick Foran as Steve Banning
Peggy Moran as Marta Solvani
Wallace Ford as “Babe” Jenson
George Zucco as Prof/ Andoheb
Cecil Kellaway as The Great Solvani
Charles Trowbridge as Dr. Petrie
Tom Tyler as Kharis

Ford, Zucco and Kellaway I’ve seen in a number of other things. Tyler later played Captain Marvel in the Adventures of Captain Marvel serial.