The fact that man once again completely misinterpreted this relationship was entirely according to these creatures' plans, as Arthur Dent will shortly discover.
12 seconds sound clip from The Hitchhiker's Guide to the Galaxy (1981) - Episode 3 sitcom.
You can hear this line at 00:27:51.779 in the Blu-ray version of the TV Series.
Quote context
[...]
- So they eventually gave up and left the Earth by their own means, shortly before the Vogans arrived.
- In fact, there was only one species on the planet more intelligent than dolphins.
- Earthman, we are now deep in the heart of Magrathea.
- How do you know I'm an Earthman?
- These things will become clear to you. At least clearer than at the moment.
- It is simply the gateway to a vast tract of hyperspace.
[...]