Detail work on the back
The back of the lion will be extruded and sealed in much the same way, but before it can be there is some extra geometry from the scan that needs to be identified and cleaned up first.
Zoom in on the posterior of the lion and locate the plate of points that are just dangling there, barely attached to anything shown in the following screenshot. Because more or less vertices may have been deleted when the part was trimmed what is left may differ, but the spurious geometry should be there.
Select these points using any desired method:
Border Select (B), Circle Select (C), or select (right-click) the points in the middle and expand the selection (Ctrl + Numpad +) until the desired points are selected.
Deselect (middle-click) the point at the very tip (indicated in the following screenshot) since that point is shared with the main body of the lion and should probably be left.
Then Delete (X) the selected points.
When those points are deleted, select the spur sticking out of...
