Problem Modeling a turtle

So I’m currently working on getting better at modeling, but here’s a problem I keep running into. Here’s the file.
http://www.sendspace.com/file/jloaeq

I modeled this turtle starting from the center of the shell out, and then duplicated and mirrored the other side so it would be symmetrical but for some reason the duplicated side came out all messed up(the right side of the turtle is the messed up side. I’m wondering if anyone has any suggestions or insight to what I might be doing wrong.

Thanks!

really messy indeed, i recomend you to star over, there some problem with you mesh, need to be more clean, there two poligons in the same space, that generated artifact in the view, try the mirror modifier next time, that make easy all… read tutorials!! :yes:

I think you have too darn many interior faces, making all your edges non-manifold. Erase them all, then recalculating normals should work and it should un-crappify.
There seem to be a humungous amount, though… maybe you should go with plan A.