Analysis of Seal Lullaby

Oh! hush thee, my baby, the night is behind us
And black are the waters that sparkled so green.
The moon, O'er the combers, looks downward to find us
At rest in the hollows that rustle between.
Where billow meets billow, there soft by the pillow.
Oh, weary wee flipperling, curl at thy ease!
The storm shall not wake thee, no shark shall overtake thee
Asleep in the storm of slow-swinging seas.