Hi, All.   I don't have a clue what these are, but I'm guessing a bivalve of some kind?  They came from the desert sand near Agadez, Niger, but that's all I know.  The street merchant I got them from thought they were dino toes, but I'm guessing not....  The thing that confuses me the most (other than the fact that I haven't been able to find any pictures of bivalves that look like this) is that it doesn't look like the "shell" would actually close like a clam or mussel.  Any and all h