Re: why does crayfish have teeth in stomach?

Crayfish, like all crustaceans have a long set of mouthpart pairs that go 
down their digestive system.

Without going into long details about each pair of mouthparts; I'll just 
explain briefly what the idea is...

Food gets grabbed by the big claws on the front, then transferred to the 
mouth, where small "arms" tear off bite sized pieces of food. Then another 
pair of mouthparts start grinding it up - food gets transferred past here 
and is ground up into a paste before transferral to the stomach.

Had a look for websites and wasnt' very successful. If you want to know 
more - check out some specific crustacean biology books in your library.

cheers,

Alastair