How do these lines from "Sailing to Byzantium" scan in terms of meter and rhyme scheme?Consume my heart away; sick with desire And fastened to a...

The rhyme scheme of "Sailing to Byzantium" is consistent
throughout and the meter is predominantly iambic pentameter. The fact that there may be
deviations from strict iambic pentameter is not unusual. Shakespeare did it frequently
in his sonnets. It is the dominant meter that counts. Keats' "Ode to a Nightingale" is
in iambic pentameter, but consider the line

Fast
fading violets covered up in leaves.

The line
not only does not scan as iambic pentameter, but it contains eleven syllables. It seems
to be intentionally syncopated. 

The rhyme scheme "Sailing
to Byzantium" is the same in all four stanzas. Take the first
stanza:

THAT is no country for old men. The
young
In one another's arms, birds in the
trees
- Those dying generations - at their
song,
The salmon-falls, the mackerel-crowded
seas,
Fish, flesh, or fowl, commend all summer
long
Whatever is begotten, born, and
dies.
Caught in that sensual music all
neglect
Monuments of unageing
intellect.

The first six lines are ABABAB, and there is a
rhyming couplet in the last two lines, making the whole stanza
ABABABCC.

young
trees
song
seas
long
dies
neglect
intellect

Half
rhyme or slant rhyme, sometimes
called near-rhyme or lazy rhyme, is a type of
rhyme formed by words with similar but not identical
sounds.
Wikipedia

Emily Dickinson was
noted for using such half rhymes, or slant rhymes, or near-rhymes, or lazy rhymes in her
poetry.

The second stanza of Yeats' poem would have to be
represented as DEDEDEFF, since there are no words in the second stanza that rhyme with
any of the last lines in the first.

Then the third stanza would be
GHGHGHII, and the fourth stanza would be JKJKJKLL.

Altogether the
rhyme scheme would
be:

ABABABCC
DEDEDEFF
GHGHGHII
JKJKJKLL

Consume
my heart away; sick with desire
And fastened to a dying
animal
It knows not what it is, and gather
me
Into the artifice of
eternity.

There are many cases in which the rhymes are only
approximate. In the above four lines "animal" is rhymed with "soul" which went before
it. Yeats is obviously not terribly concerned about exact rhyming and neither is he
concerned about strict adherence to the dominant iambic pentameter rhythm. The line
"Into the artifice of eternity," for example, has an extra syllable and deviates from
iambic meter. It would be hard to scan; it almost sounds like
prose.