Looks like either a dark normal or, based on the speckling around the markings on the side, a granite. Granites are a little-known morph in bps that basically look EXACTLY like normals to the untrained eyes.. I hadn't even heard of them until I saw hatchlings at an expo and bought one for my friend (the price difference was almost nonexistent, too; $25 for normals and $35 for granites). Some photos for your reference:

Normal: http://www.ballpythonworld.com/Ball%...e%20Normal.jpg
Granite: http://livingartreptiles.tripod.com/...g.w300h281.jpg