drbill:A source? Actually it was fairly common knowledge some time ago. You can tell the difference by the way the muscle fibers run. True scallops have muscle fibers running end to end. Ray wings have muscle fibers running "across" the piece if you look at it from one end. This is the reason that food packagers had to re-label so-called "sea scallops" in the past.
Back in the late 60's and early 70's when I used to spearfish, we'd take bat rays and create "scallops" out of them ourselves. They were fairly tasty, although nowhere near as sweet as the rock scallops here are.
Interesting, I never knew that. Wish I can find the source on that so I can learn more about it. I am much younger than you, so that's new to me.