Remember that poems do not need to have a regular set metre or rhyme scheme, and this poem is certainly an example of Whitman defying traditional forms of poetry to achieve his own effects. Whitman's poetry owes a huge debt to music, and this is something that can be seen in the first twenty-two lines. Although there is no regular metre or rhyme scheme, note the way that Whitman uses rhythm to enact the movement of the sea that he is describing. For example, there is an intensifying of pressure in lines 8 to 15:
From the memories of the bird that chanted to me,
From your memories, sad brother--from the fitful risings and fallings I heard,
From under that yellow half-moon, late-risen, and swollen as if with tears,
From those beginning notes of sickness and love, there in the transparent mist,
From the thousand responses of my heart, never to cease,
From the myriad thence-arous'd words,
From the word stronger and more delicious than any,
From such, as now they start, the scene revisiting...
Note the way that each line begins with the word "From." The effect is to convey a build up of pressure and intensity that mirrors the setting: a powerful wave gaining in momentum and power, only to crest and break before lapping gently into the shore with the half-line "A reminiscence sing." This is an excellent example of how form is used to enact the setting and the meaning of the poem, as the sea is an excellent metaphor for the turbulent emotions the speaker is experiencing.