Thought of something...
 

My two favorite characters are the sligs and the paramites. I was thinking...it's obvious that sligs and paramites are on the same evolutionary line (short or no legs, and fingerlike projections coming from the mouth.) Well, do you think sligs are able to move their tentacle/mouth-finger thingies the way paramites can? Apparently they can be moved a little, but maybe they have full flexability when they take off their masks. That'd be creepy.
(Paramites scared the hell out of me the first time I saw them. :P )

well i seriously doubt sligs are related to paramites. Two species are not necessarily related if they have simular features.
As for the tentacle flexiblily I believe they are quite flexible almost to the point of being a third 'hand'. At least...thats how my Drakkic's characters are...hehe

Paramites first scared me too. I went to gamespeak and paramite and *yuck!* But now I don't find them scary anymore. just look at my name and you know what i think of paramites! Howdy!

Let's me wonder, how do sligs talk? I don't see any mouth. Do they have mouths under their masks?

I don't think Sligs and Paramites are related as closely as it immediately seems. Paramites seem more mammal-like, while Sligs are defenately mollusc-originated. Even though the words 'mammal' and 'mollusc' mean nothing to Oddworld, the diference is noticable.

Sligs' 'tentacles', I think, enclose a mouth, or more correctly, a beak, just like Earth squids have. I don't think Sligs have much control over their tentacles, now that they have hands and tools for opening tinned beans. Maybe in the past they used them like a starfish uses its arms, for forcing apart shells and the like. There certainly doesn't seem to be bone inside them, and they don't look very strong any more.

flying sligs use their tenticles for pulling levers, so they must be controllable so a certain extent...

parallel evolution is one possiblity...

I doubt the belief that they are related. They do both have similar facial structure, but it stops there. Their bodies are completely different and also their intellectual abilities and behavior. As for a Slig's mouth, there is a movie on Oddworld.com of a BBS advertising for Blitz Packer (I'm sure most of you know the one I'm talking about), and if you look carefully at the scene where the Big Bro throws a can in the worker Slig's mouth, you notice a small jaw just behind the face mask. See if you can notice it. I also believe that a Slig's tentacles are very flexible and can be used in the manner of a hand.