I managed to eat at the original M Wells in Queens in the year or so that it was open and the most memorable thing from that dinner was their marrow and escargot dish. It was a full on bone cracked in half so you could get at the marrow with little escargots dotting it, so delicious, though I don’t recall any particularly special utensils with it.
However, if you were a hostess in the 17th or 18th century and you didn’t want your guests sucking on bones at the dinner table, you would have special suuuuuuuper skinny spoons called marrow spoons to allow diners to get inside bones and scoop out all that delicious marrow.
They seem to have fallen out of fashion by the Victorian period or later, Emily Post doesn’t mention them at all.
Luckily for us, Martha Stewart, in all her glory, has a video tutorial of how to use them: http://www.marthastewart.com/916502/how-use-18th-century-marrow-spoons
So tell me, have you eaten marrow? Do you like it? Did you use a marrow spoon?