If you were looking, Ballistic is still selling, but unfortunately the cheaper soft cover has sold out. At least it isn't only the limited edition available.
http://www.ballisticpublishing.com/books/oddworld/
The Luskan has an exoskeleton of some description, and stands on three legs resembling elongate crab claws. It has two arms, each ending with three fingers that in it's resting position continue the arm's shape to a point. It's head is very loosely like that of the herbiverous meetle, but with six 'mandibles' attached to the sides, the top pair above the eyes and the other two below. The middle pair is about 3/4 again larger than the other two pairs.. The head pokes forward, so it's shoulders/back (since it's a round dome) pokes slightly above the top point of the head.
I'll throw in the written description alongside the picture for good measure:
"Nothing more than scavenging mercenaries. So ruthless, they will even turn on eachother. Even Meetles don't turn on eachother. As ruthless as Meetles are, they have a group mentality, they work for the good of the whole group...not Lusks. Lusks will work together well, until...if they see their self interest served the Lusk may just bail and leave the rest of the group hanging, not caring at all how it may effect the rest of the group.
Lusks are only interested in their own individual needs. There is one good thing: Every Lusk knows this. They have learned to work this constant state of open misstrust...it is a wonder how they managed to evolve as a race."
By Farzard, Munch concept.