34.

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Across
  1. 2. Octad parts
  2. 4. Between hexad and octad
  3. 7. Featured artist on Gotye's Somebody That I Used to Know the #8 song of the 2010s
  4. 8. Eight Songs for a Mad King composer, Master of the Queen's Music 2004-14 (6)
  5. 10. Octad plus one
Down
  1. 1. Octad in a gallon
  2. 3. Between hexad and octad
  3. 5. Eight's follower, CB Radio style
  4. 6. Nine-minus-eight's sum
  5. 9. Ashcan School artist