Pifias

When Dunning and the Doctor are examining the monster's flesh under their microscope, man on boat deck behind them suddenly appears and then disappears.

The microscope being used is a transmitted light type requiring the mirror under the stage to be angled to reflect light from a light source up and through the specimen so it can be seen. No one ever bothers to set the angle of the mirror.

When the two scientists are having a discussion aboard their boat, they refer to flying reptiles. The first says that they have been extinct since the end of the Stone Age (5,000 years ago). The second says that they have been gone for hundreds of centuries. In fact, they have been extinct for 65 million years.

When Julie first encounters Steve in his mini submarine they are both in the water. Julie gets out of the water and runs onto the beach. Steve runs up behind her. The mini sub is also on the beach. How'd the sub get out of the water?

As the film opens, and the camera pans to a landscape where "no white man has ever been," at the top right of the screen a car can be seen traveling down Pacific Coast Highway in Malibu, where this scene was filmed.

At 2:09 there is an error in the subtitles. The actress asks "Was he drowned?" The subtitle has "Was he drunk?"

The poster shows Julie attacked on the beach, hair flowing out. When she's attacked in the film, it's underwater, and she's wearing scuba gear and a bathing cap.