Intelligent Design

[henk brouwer]

The crab design, or some simillar design (spiders with crab claws) would work on land too.

The gathering of the main sensors and processing core is a valid point though, some variation might be possible since aliens are unlikely to have evolved the same nervous system that we have.

[Captain Kwok]

Although I thought there is a size limitation on how big an exoskeleton can be before it couldn't support it's weight (at least in Earth's gravity. )?

[Phoenix-D]

There is. Its the same reason you don't find 6-foot wide cells.