I could have sworn I posted about this recently, but since I can't find the post...
We recently spotted large (pound and a half) Jonah crabs at Clem and Ursie's fish market on Shankpainter Road in Provincetown. Most of you probably know that these are the crabs from which Maine crabmeat comes, and that the Jonah is more closely related to the Dungeness than the Maryland blue crab.
At $2.50 a crab, the price was right, so I steamed up 4 of them for our dinner. I let them cool a bit and served them with mayonnaise-cocktail sauce- mustard accompaniment. Picking crabs is work, but the meat is sweeter than lobster, and the effort is well worth it.
I have seen the crabs in other markets as well, for example in Nickerson's on the Chatham pier. For those of you visiting Cape Cod with a place to cook, I encourage you to try these.