Originally Posted by Olympia
It's technically an improper term grammatically.. Platypodes would be the correct way to say it grammatically, but most people just say platypus as the plural or even platypuses. People do use platypi as well.. It's like how people say octopuses/octopi/octopodes.. Or even fish and fishes.. Even though some of them are technically grammatically incorrect when looking at Latin/Greek (whichever is the origin of the word), it's so commonly used that there isn't really a "correct" way to say it, all forms are accepted. Just whichever you prefer.
Actually its placostomus. Which its a greek word meaning wide mouth.
Platypodas means wide foot. Unless i am mistaken and we are talking about a different species. :)
As for the octopus its octapodi / octapodes which means 8 legs.