Patch question

[alphacat]

A friend send me a picture of her dad who was in the Marines. It looks like a WWII picture, maybe Korea.
He has a patch on his left arm that is in a shield shape with what looks like III across the top with a flying dragon on it.

Any ideas what it is or maybe a place I can look it up?

thanks

I forgot to say, it's on his jacket I can't see his shirt.

[alphacat]

I found it, it's a marine 3rd amphibious corps patch.