Here is another one, again, trying to minimize text and make it more about the information than anything else.

Some of this is more opinion, like dorsal placement, but the rest is from studying how anatomy works for dolphins.

References:
Terryl Whitlatch's book Animals: Real and Imagined
redraptor16
Proko's art tutorials for anatomy
Various assortments of images and other books.

Art © Me,   Adleisio