Natarl

Among the aliens stuck on Denossus was a being with a distinctive helmet and webbed hands and feet. (COMIC: Land of the Blind)

Four of these beings were once at a beach in a valley. (The Dr Who Annual 1966 Contents)

Several of these beings were also seen on the Moon. (The Dr Who Annual 1969 frontispiece)

Behind the scenes
These aliens are Natarls from the film (1959).