There are legless lizards though. How do you know that this is not one? Are you familiar with the species?
edit: Just did a google search on the species name, Rhineura floridana, every hit said either worm lizard or florida worm lizard. I didn't actually check the sites, but unless it's a snake that's called a lizard then it is fact a legless lizard.
Enigma, Do what I just did and if you're patient enough, you'll probably find a link telling you why it is a lizard and not a snake. It can be difficult sometimes to come up with useful information. Maybe somebody that really knows will come across your thread.
