What message is sent by the nautilus in stanza 4?
In Oliver Wendell Holmes' poem "The Chambered Nautilus," the poet describes through the first three stanzas, the practice of sea creatures living in a shell for a time. And when a creature decides it is time, it leaves one shell to move on to another. It attaches itself to its new abode which becomes home, while the old "dwelling place" is forgotten.
In stanza four, the poet seems to be speaking to one of the shells that has been washed ashore and retrieved by him:
Child of the wandering sea,
Cast from her lap, forlorn!
The poet personifies the shell, describing it as forlorn, and continues the personification when describing that its lips create sound:
From thy dead lips a clearer note is born
Than even Triton blew from wreathed horn.
The poet writes that while it may no longer be a home, it rings in his ear (as when one places a shell to his ear to listen to the ocean), and when deep in thought, he hears a voice singing, like the sound of the ocean.