Read "The Mime of Sleep" at The Eldritch Dark:
This sonnet from Clark Ashton Smith (CAS) follows the convention of that particular form, specifically the Italian sonnet, which traditionally divides the poem into an eight-line "proposition" (the octet) followed by a six-line "resolution" (the sestet).
CAS further adheres to the convention of creating the transition from proposition to resolution in the volta, the ninth line, which begins the fascinating conclusion to "The Mime of Sleep":
Your beauty's burning shade more slowly dims—
Where, dancing like Salome, you let fall,
In splendid sequence under a sad sky,
The seven veils of fantasy that I
Have wound about your young, delightful limbs.
The references to Salome and The Dance of the Seven Veils invoke the powerful eroticism of that Biblical episode, but also the associated decapitation of John the Baptist.
On the surface, the sestet quoted above paints a beautiful romantic image, but by incorporating allusions to the legend of the daughter of Herod II, CAS links the poem's outro to the nightmarish visions of the opening stanza, where the speaker's dreams are a "A masque, whose grey grotesques of mirth and pain / Move randomly through an occulted clime."