“Perhaps, she thought, people were more like ammonites than one would suppose. Perhaps they too built shells on a consistent, unchanging factor—some quality or circumstance established in their youth. Each chamber in the shell just an enlargement of the previous. Growing year after year, until they spiraled around and locked themselves in place.”

“Living like an empty shell is not really living, no matter how many years it may go on. The heart and flesh of an empty shell give birth to nothing more than the life of an empty shell.”

“It is perhaps a more fortunate destiny to have a taste for collecting shells than to be born a millionaire.”

“Many love stories are like the shells of hermit crabs, though others are more like chambered nautiluses, whose architecture grows with the inhabitant and whose abandoned smaller chambers are lighter than water and let them float in the sea.”

“She gazed out across the rooftops of Ankh-Morpork and reasoned like this: writing was only the words that people said, squeezed between layers of paper until they were fossilized (fossils were well known on the Discworld, great spiraled shells and badly constructed creatures that were left over from the time when the Creator hadn't really decided what He wanted to make and was, as it were, just idly messing around with the Pleistocene). And the words people said were just shadow of real things. But some things were too big to be really trapped in words, and even the words were too powerful to be completely tamed by writing.”

“The female crab has an impenetrable shell, she is so hard on the outside and yet so soft within. There is no possible point of access. The male crab must wait a whole year until the female decides to shed her shell to grow a new one. And it is only at that moment of vulnerability that the patient crab can triumph in his love.”