The shell to the right with a hole through it was hinged to another shell of equal size with an animal living inside (in this case, a clam). Animals with two shells hinged together are known as bivalves. read more
There are many marine snails that have 'drilling' capabilities. For instance, the Atlantic Oyester Drill, Urosalpinx cinerea, has a radula (teeth) which they use to drill through the shell and then eat the inhabitant. read more