This stitch is visually similar to the opened fishbone stitch, but differs technically. This kind of stitch takes a more thread than the opened fishbone stitch. 

I will be working on a leaf design, to help illustrate this stitch better. I have divided the leaf into two; technically three. I have named the the stitch lines A, B, C and D. We shall be working between these lines. This stitch is worked from top to bottom.

open_fishbone_stitch_1      open_fishbone_stitch_2
Fig 1: We will begin by bringing out the thread from D and taking it in through B. Make sure it is angled diagonally as shown in the picture.   Fig 2: Now, bring the needle out through C. Take the needle through A.
open_fishbone_stitch_3 open_fishbone_stitch_4
Fig 3: You get a stitched ‘crossed’ at the bottom. Now, continue the process by bringing the needle out through D and taking it in through B. Then, bringing it through C and taking it in through A.    Fig 4: Half way through, the leaf looks like this. We keep working outside in for one half and inside out for the other half.
open_fishbone_stitch_5   Fig 5: Our finished leaf would look like this. The stitches seen here are not diagonal enough though.