Until observations proved him right in the nineteenth century, people thought Aristotle's claims about the octopus were off the wall when he said:

"The octopus uses its tentacles both as feet and as hands...The last of them, which is very sharp and is the only one which is whitish in color and bifurcated at the tip...this one it uses in the act of copulation."

'Some say that the male octopus has a sort of penis on one of his tentacles...and that the whole of it is attatched up as far as the middle of the tentacle, which it thus admits into the 'nostril' [elsewhere called the 'funnel'] of the female." (HA IV.1 524a2-9, V.6 541b8-12., in Allan Gotthelf's "Aristotle as Scientist: A Proper Verdict".)